What's wrong with these heads ???

[Daniel]

Hello,

I just picked up a nice AKAI GX-270D open reel recorder for free and after
cleaning it and recording and playing back, the unit functions very well and
has great sound. Problem is that there's some discoloration on the heads.
I've enclosed some photos. Please let me know what you think.

http://members.shaw.ca/sivlee/DSC00059.JPG

http://members.shaw.ca/sivlee/DSC00060.JPG

THANKS!

Daniel

[Don Pearce]

On Fri, 17 Sep 2004 08:16:20 GMT, "Daniel" >
wrote:

>> There is NOTHING on that assembly that looks even remotely straight. I
>> think some major work is needed.
>
>Yeah, I think so too .... Thanks ....... Funny thing is that the machine
>still sounds better than my cd player ......
>
>Daniel
>

Time for a visit to the audiologist... ;-)

d
Pearce Consulting
http://www.pearce.uk.com

[Don Pearce]

On Fri, 17 Sep 2004 08:16:20 GMT, "Daniel" >
wrote:

>> There is NOTHING on that assembly that looks even remotely straight. I
>> think some major work is needed.
>
>Yeah, I think so too .... Thanks ....... Funny thing is that the machine
>still sounds better than my cd player ......
>
>Daniel
>

Time for a visit to the audiologist... ;-)

d
Pearce Consulting
http://www.pearce.uk.com

[Scott Dorsey]

Daniel > wrote:
>Yes, I have thoroughly cleaned the heads, the entire tape path and also the
>hard to reach areas where the heads are. The original picts are from the
>time when I just cleaned the heads. Now, it all looks clean BUT that
>yellowish/orangy color remains. To me it looks like it's below the recording
>strips, inside the heads. These are "glass heads" if this at all helps ...
>Someone said it might be "rust" ?

That's what the coating on the tape is; it's rust. Barn paint rust if you
want to get specific.

I wouldn't worry about it, but I _would_ scrub the heads very hard with
xylene. Then I would go through the alignment procedure because these are
so far out of proper alignment that the error is visible by eye. In the
process of doing the alignment you will also find out if there is a problem
with the head gap being clogged or damaged.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Daniel > wrote:
>Yes, I have thoroughly cleaned the heads, the entire tape path and also the
>hard to reach areas where the heads are. The original picts are from the
>time when I just cleaned the heads. Now, it all looks clean BUT that
>yellowish/orangy color remains. To me it looks like it's below the recording
>strips, inside the heads. These are "glass heads" if this at all helps ...
>Someone said it might be "rust" ?

That's what the coating on the tape is; it's rust. Barn paint rust if you
want to get specific.

I wouldn't worry about it, but I _would_ scrub the heads very hard with
xylene. Then I would go through the alignment procedure because these are
so far out of proper alignment that the error is visible by eye. In the
process of doing the alignment you will also find out if there is a problem
with the head gap being clogged or damaged.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Edi Zubovic]

On 17 Sep 2004 09:36:26 -0400, (Scott Dorsey) wrote:

>Daniel > wrote:
>>Yes, I have thoroughly cleaned the heads, the entire tape path and also the
>>hard to reach areas where the heads are. The original picts are from the
>>time when I just cleaned the heads. Now, it all looks clean BUT that
>>yellowish/orangy color remains. To me it looks like it's below the recording
>>strips, inside the heads. These are "glass heads" if this at all helps ...
>>Someone said it might be "rust" ?
>
>That's what the coating on the tape is; it's rust. Barn paint rust if you
>want to get specific.
>
>I wouldn't worry about it, but I _would_ scrub the heads very hard with
>xylene. Then I would go through the alignment procedure because these are
>so far out of proper alignment that the error is visible by eye. In the
>process of doing the alignment you will also find out if there is a problem
>with the head gap being clogged or damaged.
>--scott

--Pardon me, but are these Akai heads clad with a sort of Pyrex glass
(GX heads, "Glass" and "Xtal" I think while that "X" might be anything
hard, even diamond, I presume at the gap area), as I have read about
eons ago? They were really built to last and yes, Akai has been always
sounding superbly to me, even cassette recorders were built like tank.
This tape deck can sound better than a CD indeed <g>.

This coloration might well be an oxide residue. As Scott recommended,
scrub it away, demagnetize the heads and the tape path and align by
using a known good tape set to mono, listennig to highest tones.

Edi Zubovic, Crikvenica, Croatia

[Edi Zubovic]

On 17 Sep 2004 09:36:26 -0400, (Scott Dorsey) wrote:

>Daniel > wrote:
>>Yes, I have thoroughly cleaned the heads, the entire tape path and also the
>>hard to reach areas where the heads are. The original picts are from the
>>time when I just cleaned the heads. Now, it all looks clean BUT that
>>yellowish/orangy color remains. To me it looks like it's below the recording
>>strips, inside the heads. These are "glass heads" if this at all helps ...
>>Someone said it might be "rust" ?
>
>That's what the coating on the tape is; it's rust. Barn paint rust if you
>want to get specific.
>
>I wouldn't worry about it, but I _would_ scrub the heads very hard with
>xylene. Then I would go through the alignment procedure because these are
>so far out of proper alignment that the error is visible by eye. In the
>process of doing the alignment you will also find out if there is a problem
>with the head gap being clogged or damaged.
>--scott

--Pardon me, but are these Akai heads clad with a sort of Pyrex glass
(GX heads, "Glass" and "Xtal" I think while that "X" might be anything
hard, even diamond, I presume at the gap area), as I have read about
eons ago? They were really built to last and yes, Akai has been always
sounding superbly to me, even cassette recorders were built like tank.
This tape deck can sound better than a CD indeed <g>.

This coloration might well be an oxide residue. As Scott recommended,
scrub it away, demagnetize the heads and the tape path and align by
using a known good tape set to mono, listennig to highest tones.

Edi Zubovic, Crikvenica, Croatia

[Arny Krueger]

"Edi Zubovic" <edi.zubovic.[rem > wrote in message


> --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
> (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
> hard, even diamond, I presume at the gap area), as I have read about
> eons ago? They were really built to last and yes, Akai has been always
> sounding superbly to me, even cassette recorders were built like tank.

My recollection is that the glass was in the gap, and the X related to
crossfield biasing.

> This tape deck can sound better than a CD indeed <g>.

Better sounding perhaps, but unlike good digital not identical.

[Arny Krueger]

"Edi Zubovic" <edi.zubovic.[rem > wrote in message


> --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
> (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
> hard, even diamond, I presume at the gap area), as I have read about
> eons ago? They were really built to last and yes, Akai has been always
> sounding superbly to me, even cassette recorders were built like tank.

My recollection is that the glass was in the gap, and the X related to
crossfield biasing.

> This tape deck can sound better than a CD indeed <g>.

Better sounding perhaps, but unlike good digital not identical.

[Daniel]

"Edi Zubovic" <edi.zubovic.[rem > wrote in message
...
> On 17 Sep 2004 09:36:26 -0400, (Scott Dorsey) wrote:
>
> >Daniel > wrote:
> >>Yes, I have thoroughly cleaned the heads, the entire tape path and also
the
> >>hard to reach areas where the heads are. The original picts are from the
> >>time when I just cleaned the heads. Now, it all looks clean BUT that
> >>yellowish/orangy color remains. To me it looks like it's below the
recording
> >>strips, inside the heads. These are "glass heads" if this at all helps
....
> >>Someone said it might be "rust" ?
> >
> >That's what the coating on the tape is; it's rust. Barn paint rust if
you
> >want to get specific.
> >
> >I wouldn't worry about it, but I _would_ scrub the heads very hard with
> >xylene. Then I would go through the alignment procedure because these
are
> >so far out of proper alignment that the error is visible by eye. In the
> >process of doing the alignment you will also find out if there is a
problem
> >with the head gap being clogged or damaged.
> >--scott
>
> --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
> (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
> hard, even diamond, I presume at the gap area), as I have read about
> eons ago? They were really built to last and yes, Akai has been always
> sounding superbly to me, even cassette recorders were built like tank.
> This tape deck can sound better than a CD indeed <g>.
>
> This coloration might well be an oxide residue. As Scott recommended,
> scrub it away, demagnetize the heads and the tape path and align by
> using a known good tape set to mono, listennig to highest tones.
>
> Edi Zubovic, Crikvenica, Croatia

Yes, you are correct. These are "Glass" heads.

Thanks for the info.

Daniel

[Daniel]

"Edi Zubovic" <edi.zubovic.[rem > wrote in message
...
> On 17 Sep 2004 09:36:26 -0400, (Scott Dorsey) wrote:
>
> >Daniel > wrote:
> >>Yes, I have thoroughly cleaned the heads, the entire tape path and also
the
> >>hard to reach areas where the heads are. The original picts are from the
> >>time when I just cleaned the heads. Now, it all looks clean BUT that
> >>yellowish/orangy color remains. To me it looks like it's below the
recording
> >>strips, inside the heads. These are "glass heads" if this at all helps
....
> >>Someone said it might be "rust" ?
> >
> >That's what the coating on the tape is; it's rust. Barn paint rust if
you
> >want to get specific.
> >
> >I wouldn't worry about it, but I _would_ scrub the heads very hard with
> >xylene. Then I would go through the alignment procedure because these
are
> >so far out of proper alignment that the error is visible by eye. In the
> >process of doing the alignment you will also find out if there is a
problem
> >with the head gap being clogged or damaged.
> >--scott
>
> --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
> (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
> hard, even diamond, I presume at the gap area), as I have read about
> eons ago? They were really built to last and yes, Akai has been always
> sounding superbly to me, even cassette recorders were built like tank.
> This tape deck can sound better than a CD indeed <g>.
>
> This coloration might well be an oxide residue. As Scott recommended,
> scrub it away, demagnetize the heads and the tape path and align by
> using a known good tape set to mono, listennig to highest tones.
>
> Edi Zubovic, Crikvenica, Croatia

Yes, you are correct. These are "Glass" heads.

Thanks for the info.

Daniel

[Daniel]

"Don Pearce" > wrote in message
...
> On Fri, 17 Sep 2004 08:16:20 GMT, "Daniel" >
> wrote:
>
> >> There is NOTHING on that assembly that looks even remotely straight. I
> >> think some major work is needed.
> >
> >Yeah, I think so too .... Thanks ....... Funny thing is that the machine
> >still sounds better than my cd player ......
> >
> >Daniel
> >
>
> Time for a visit to the audiologist... ;-)

Well, I recorded a cd to the AKAI and it captured all of the detail of CD
plus made it "BIGGER" and "THICKER" sounding for some reason, bringing the
CD material to life. (I used 7 1/2 ips and Quantegy 456). I may need an
"audiologist" but I still like what I hear ;-)))

Daniel

>
> d
> Pearce Consulting
> http://www.pearce.uk.com

[Daniel]

"Don Pearce" > wrote in message
...
> On Fri, 17 Sep 2004 08:16:20 GMT, "Daniel" >
> wrote:
>
> >> There is NOTHING on that assembly that looks even remotely straight. I
> >> think some major work is needed.
> >
> >Yeah, I think so too .... Thanks ....... Funny thing is that the machine
> >still sounds better than my cd player ......
> >
> >Daniel
> >
>
> Time for a visit to the audiologist... ;-)

Well, I recorded a cd to the AKAI and it captured all of the detail of CD
plus made it "BIGGER" and "THICKER" sounding for some reason, bringing the
CD material to life. (I used 7 1/2 ips and Quantegy 456). I may need an
"audiologist" but I still like what I hear ;-)))

Daniel

>
> d
> Pearce Consulting
> http://www.pearce.uk.com

[Daniel]

"Scott Dorsey" > wrote in message
...
> Daniel > wrote:
> >Yes, I have thoroughly cleaned the heads, the entire tape path and also
the
> >hard to reach areas where the heads are. The original picts are from the
> >time when I just cleaned the heads. Now, it all looks clean BUT that
> >yellowish/orangy color remains. To me it looks like it's below the
recording
> >strips, inside the heads. These are "glass heads" if this at all helps
....
> >Someone said it might be "rust" ?
>
> That's what the coating on the tape is; it's rust. Barn paint rust if you
> want to get specific.
>
> I wouldn't worry about it, but I _would_ scrub the heads very hard with
> xylene. Then I would go through the alignment procedure because these are
> so far out of proper alignment that the error is visible by eye. In the
> process of doing the alignment you will also find out if there is a
problem
> with the head gap being clogged or damaged.
> --scott

Would you by any chance know of a website (info) that takes you step by step
to do the alignment yourself ?

Btw, I'm nicely restoring this beautiful deck and it's looking better and
better. That "residue" however, looks to me as if it's under the heads,
under the glass. The surface of the heads is looking flawless however.

I will post some more picts soon!

Thanks Scott!

Daniel


>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

[Daniel]

"Scott Dorsey" > wrote in message
...
> Daniel > wrote:
> >Yes, I have thoroughly cleaned the heads, the entire tape path and also
the
> >hard to reach areas where the heads are. The original picts are from the
> >time when I just cleaned the heads. Now, it all looks clean BUT that
> >yellowish/orangy color remains. To me it looks like it's below the
recording
> >strips, inside the heads. These are "glass heads" if this at all helps
....
> >Someone said it might be "rust" ?
>
> That's what the coating on the tape is; it's rust. Barn paint rust if you
> want to get specific.
>
> I wouldn't worry about it, but I _would_ scrub the heads very hard with
> xylene. Then I would go through the alignment procedure because these are
> so far out of proper alignment that the error is visible by eye. In the
> process of doing the alignment you will also find out if there is a
problem
> with the head gap being clogged or damaged.
> --scott

Would you by any chance know of a website (info) that takes you step by step
to do the alignment yourself ?

Btw, I'm nicely restoring this beautiful deck and it's looking better and
better. That "residue" however, looks to me as if it's under the heads,
under the glass. The surface of the heads is looking flawless however.

I will post some more picts soon!

Thanks Scott!

Daniel


>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

[Daniel]

"Arny Krueger" > wrote in message
...
> "Edi Zubovic" <edi.zubovic.[rem > wrote in message
>
>
> > --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
> > (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
> > hard, even diamond, I presume at the gap area), as I have read about
> > eons ago? They were really built to last and yes, Akai has been always
> > sounding superbly to me, even cassette recorders were built like tank.
>
> My recollection is that the glass was in the gap, and the X related to
> crossfield biasing.

What is "crossfield biasing" ? On the cover it says "Focused Field" ??? What
is that ?

>
> > This tape deck can sound better than a CD indeed <g>.
>
> Better sounding perhaps, but unlike good digital not identical.

Yeah, the Akai has nicer sound characteristics but digital is "accurate" so
we're talking about two different sounds. Both have their uses.

Daniel


>
>
>
>

[Daniel]

"Arny Krueger" > wrote in message
...
> "Edi Zubovic" <edi.zubovic.[rem > wrote in message
>
>
> > --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
> > (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
> > hard, even diamond, I presume at the gap area), as I have read about
> > eons ago? They were really built to last and yes, Akai has been always
> > sounding superbly to me, even cassette recorders were built like tank.
>
> My recollection is that the glass was in the gap, and the X related to
> crossfield biasing.

What is "crossfield biasing" ? On the cover it says "Focused Field" ??? What
is that ?

>
> > This tape deck can sound better than a CD indeed <g>.
>
> Better sounding perhaps, but unlike good digital not identical.

Yeah, the Akai has nicer sound characteristics but digital is "accurate" so
we're talking about two different sounds. Both have their uses.

Daniel


>
>
>
>

[Edi Zubovic]

On Sat, 18 Sep 2004 20:26:12 GMT, "Daniel" >
wrote:

--------8<snippetysnip----------------------
>>
>> --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
>> (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
>> hard, even diamond, I presume at the gap area), as I have read about
>> eons ago? They were really built to last and yes, Akai has been always
>> sounding superbly to me, even cassette recorders were built like tank.
>> This tape deck can sound better than a CD indeed <g>.
>>
>> This coloration might well be an oxide residue. As Scott recommended,
>> scrub it away, demagnetize the heads and the tape path and align by
>> using a known good tape set to mono, listennig to highest tones.
>>
>> Edi Zubovic, Crikvenica, Croatia
>
>Yes, you are correct. These are "Glass" heads.
>
>Thanks for the info.
>
>Daniel
>
You're welcome -- actually I had, way back in 1978, an Akai, I think
570 D or thereabouts, big reels, in a nearby discoteque for several
months. I even did a not-so-bad probe recording with it of a local
dancing band. I remember those GX heads which looked mighty and were
triangular shaped (I think that might be a part of that "Focused
Field" system). This deck wasn't mine but I wished it was. It had
double capstan drive too and relay controlled logics fucnction. Oh the
logics has been at the Akai all-discrete type, the logic PCB has been
all black from transistors and even the signal bulbs (illuminating the
pushbuttons) have been an active part of the system. If one of these
lamps failed the whole function would fail too. Replacement should be
made by a bulb having a resistance closely matching the original
otherwise the function wouldn't work too. An old oscilloscope has been
a bless when one of these lamps and a transistor failed at such Akai
cassette deck.

Owing to these heads, the Akais should sound good even today,
mechanics (rubber and plastics) and electronics (capacitors etc.)
permitting.

Edi Zubovic, Crikvenica, Croatia

PS. Hmmm, I would address the "Crossfield" technology rather to
Tandberg -- still another excellent tape recorder builders of the era
-- which had in addition to normal heads, also had a head or two at
the opposite side of the tape path; at the same positions only looking
at the back of the tape.
Man, the more I think about these machines, the more is squeezed out
of the memory :))

[Edi Zubovic]

On Sat, 18 Sep 2004 20:26:12 GMT, "Daniel" >
wrote:

--------8<snippetysnip----------------------
>>
>> --Pardon me, but are these Akai heads clad with a sort of Pyrex glass
>> (GX heads, "Glass" and "Xtal" I think while that "X" might be anything
>> hard, even diamond, I presume at the gap area), as I have read about
>> eons ago? They were really built to last and yes, Akai has been always
>> sounding superbly to me, even cassette recorders were built like tank.
>> This tape deck can sound better than a CD indeed <g>.
>>
>> This coloration might well be an oxide residue. As Scott recommended,
>> scrub it away, demagnetize the heads and the tape path and align by
>> using a known good tape set to mono, listennig to highest tones.
>>
>> Edi Zubovic, Crikvenica, Croatia
>
>Yes, you are correct. These are "Glass" heads.
>
>Thanks for the info.
>
>Daniel
>
You're welcome -- actually I had, way back in 1978, an Akai, I think
570 D or thereabouts, big reels, in a nearby discoteque for several
months. I even did a not-so-bad probe recording with it of a local
dancing band. I remember those GX heads which looked mighty and were
triangular shaped (I think that might be a part of that "Focused
Field" system). This deck wasn't mine but I wished it was. It had
double capstan drive too and relay controlled logics fucnction. Oh the
logics has been at the Akai all-discrete type, the logic PCB has been
all black from transistors and even the signal bulbs (illuminating the
pushbuttons) have been an active part of the system. If one of these
lamps failed the whole function would fail too. Replacement should be
made by a bulb having a resistance closely matching the original
otherwise the function wouldn't work too. An old oscilloscope has been
a bless when one of these lamps and a transistor failed at such Akai
cassette deck.

Owing to these heads, the Akais should sound good even today,
mechanics (rubber and plastics) and electronics (capacitors etc.)
permitting.

Edi Zubovic, Crikvenica, Croatia

PS. Hmmm, I would address the "Crossfield" technology rather to
Tandberg -- still another excellent tape recorder builders of the era
-- which had in addition to normal heads, also had a head or two at
the opposite side of the tape path; at the same positions only looking
at the back of the tape.
Man, the more I think about these machines, the more is squeezed out
of the memory :))

[Arny Krueger]

"Daniel" > wrote in message
news:M%03d.463609$gE.34046@pd7tw3no
> "Arny Krueger" > wrote in message
> ...
>> "Edi Zubovic" <edi.zubovic.[rem > wrote in message
>>
>>
>>> --Pardon me, but are these Akai heads clad with a sort of Pyrex
>>> glass (GX heads, "Glass" and "Xtal" I think while that "X" might be
>>> anything hard, even diamond, I presume at the gap area), as I have
>>> read about eons ago? They were really built to last and yes, Akai
>>> has been always sounding superbly to me, even cassette recorders
>>> were built like tank.
>>
>> My recollection is that the glass was in the gap, and the X related
>> to crossfield biasing.
>
> What is "crossfield biasing" ? On the cover it says "Focused Field"
> ??? What is that ?

The recording bias was applied by a separate head that rode on the back side
of the tape, its gap lined up with the gap of the recording head. Therefore
there was very little bias current flowing through the recording head.

[Arny Krueger]

"Daniel" > wrote in message
news:M%03d.463609$gE.34046@pd7tw3no
> "Arny Krueger" > wrote in message
> ...
>> "Edi Zubovic" <edi.zubovic.[rem > wrote in message
>>
>>
>>> --Pardon me, but are these Akai heads clad with a sort of Pyrex
>>> glass (GX heads, "Glass" and "Xtal" I think while that "X" might be
>>> anything hard, even diamond, I presume at the gap area), as I have
>>> read about eons ago? They were really built to last and yes, Akai
>>> has been always sounding superbly to me, even cassette recorders
>>> were built like tank.
>>
>> My recollection is that the glass was in the gap, and the X related
>> to crossfield biasing.
>
> What is "crossfield biasing" ? On the cover it says "Focused Field"
> ??? What is that ?

The recording bias was applied by a separate head that rode on the back side
of the tape, its gap lined up with the gap of the recording head. Therefore
there was very little bias current flowing through the recording head.

[Paul Stamler]

"Edi Zubovic" <edi.zubovic.[rem > wrote in message

> PS. Hmmm, I would address the "Crossfield" technology rather to
> Tandberg -- still another excellent tape recorder builders of the era
> -- which had in addition to normal heads, also had a head or two at
> the opposite side of the tape path; at the same positions only looking
> at the back of the tape.

Both Akai (Roberts in the USA) and Tandberg used the "Crossfield" design; I
don't recall it with great detail, since I never had a tape recorder that
used it, but I seem to remember that its primary strength was wider
frequency response at 3-3/4, 1-7/8 and 15/16 ips speeds.

Peace,
Paul

[Paul Stamler]

"Edi Zubovic" <edi.zubovic.[rem > wrote in message

> PS. Hmmm, I would address the "Crossfield" technology rather to
> Tandberg -- still another excellent tape recorder builders of the era
> -- which had in addition to normal heads, also had a head or two at
> the opposite side of the tape path; at the same positions only looking
> at the back of the tape.

Both Akai (Roberts in the USA) and Tandberg used the "Crossfield" design; I
don't recall it with great detail, since I never had a tape recorder that
used it, but I seem to remember that its primary strength was wider
frequency response at 3-3/4, 1-7/8 and 15/16 ips speeds.

Peace,
Paul

[Scott Dorsey]

Daniel > wrote:
>
>
>Well, I recorded a cd to the AKAI and it captured all of the detail of CD
>plus made it "BIGGER" and "THICKER" sounding for some reason, bringing the
>CD material to life. (I used 7 1/2 ips and Quantegy 456). I may need an
>"audiologist" but I still like what I hear ;-)))

That bigness and thickness is the result of low end distortion because your
bias is incorrect for that tape. The azimuth error isn't helping.
--scott
>
>Daniel
>
>>
>> d
>> Pearce Consulting
>> http://www.pearce.uk.com
>
>


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Daniel > wrote:
>
>
>Well, I recorded a cd to the AKAI and it captured all of the detail of CD
>plus made it "BIGGER" and "THICKER" sounding for some reason, bringing the
>CD material to life. (I used 7 1/2 ips and Quantegy 456). I may need an
>"audiologist" but I still like what I hear ;-)))

That bigness and thickness is the result of low end distortion because your
bias is incorrect for that tape. The azimuth error isn't helping.
--scott
>
>Daniel
>
>>
>> d
>> Pearce Consulting
>> http://www.pearce.uk.com
>
>


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Daniel > wrote:
>
>Would you by any chance know of a website (info) that takes you step by step
>to do the alignment yourself ?

You really will need the service manual. The FAQ for this group discusses
how to do recorder alignment, but many of the consumer machines have some
oddities (for example, many of them don't have playback EQ adjustments at
all and some don't have a record treble adjustment). The group FAQ also
talks mostly about biasing with the overbias method, which may not work on
some consumer machines that are limited to lower bias tape types.

The Akai machine is designed for use with JIS-standard tape; the Japanese
had the notion that the tape for consumer machines would all have standardized
bias so that they could be interchanged without realignment. Unfortunately
the last JIS tape made was Maxell UD, which was discontinued about a year
ago. Many of these machines do not have much adjustment range in the bias
control, because they were never intended to be used with anything else other
than that one tape type.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Daniel > wrote:
>
>Would you by any chance know of a website (info) that takes you step by step
>to do the alignment yourself ?

You really will need the service manual. The FAQ for this group discusses
how to do recorder alignment, but many of the consumer machines have some
oddities (for example, many of them don't have playback EQ adjustments at
all and some don't have a record treble adjustment). The group FAQ also
talks mostly about biasing with the overbias method, which may not work on
some consumer machines that are limited to lower bias tape types.

The Akai machine is designed for use with JIS-standard tape; the Japanese
had the notion that the tape for consumer machines would all have standardized
bias so that they could be interchanged without realignment. Unfortunately
the last JIS tape made was Maxell UD, which was discontinued about a year
ago. Many of these machines do not have much adjustment range in the bias
control, because they were never intended to be used with anything else other
than that one tape type.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[TheCatsPjamas]

<< Owing to these heads, the Akais should sound good even today,
mechanics (rubber and plastics) and electronics (capacitors etc.)
permitting.

Edi Zubovic, Crikvenica, Croatia >><BR><BR>

I agree. I have an Akai M10 that is much older than I am which still
sounds good. I keep telling myself that I will take it out some day on
a recording just for fun.




Peter


How has that Bora been lately?

[TheCatsPjamas]

<< Owing to these heads, the Akais should sound good even today,
mechanics (rubber and plastics) and electronics (capacitors etc.)
permitting.

Edi Zubovic, Crikvenica, Croatia >><BR><BR>

I agree. I have an Akai M10 that is much older than I am which still
sounds good. I keep telling myself that I will take it out some day on
a recording just for fun.




Peter


How has that Bora been lately?

[Edi Zubovic]

On 20 Sep 2004 00:55:17 GMT, (TheCatsPjamas)
wrote:

><< Owing to these heads, the Akais should sound good even today,
>mechanics (rubber and plastics) and electronics (capacitors etc.)
>permitting.
>
>Edi Zubovic, Crikvenica, Croatia >><BR><BR>
>
>I agree. I have an Akai M10 that is much older than I am which still
>sounds good. I keep telling myself that I will take it out some day on
>a recording just for fun.

Well, why not? -- Just pay a little attention if you are going to
conncect the unbalanced Akai to the balanced mixing console: this
should be made via insulating transformers (if no unbalanced
connections are provided of course).

>
>Peter
>
>
>How has that Bora been lately?

Oh the Bora wind :)) -- It has been blowing for some days recently,
sweeping the summer heat and dirt away. Nowadays after it, it's a
very fine weather. I like it. Now you can peacefully sit atop a quay
with a fishing rod in a calm sunset and take a bit of rest.

Edi Zubovic, Crikvenica, Croatia

[Edi Zubovic]

On 20 Sep 2004 00:55:17 GMT, (TheCatsPjamas)
wrote:

><< Owing to these heads, the Akais should sound good even today,
>mechanics (rubber and plastics) and electronics (capacitors etc.)
>permitting.
>
>Edi Zubovic, Crikvenica, Croatia >><BR><BR>
>
>I agree. I have an Akai M10 that is much older than I am which still
>sounds good. I keep telling myself that I will take it out some day on
>a recording just for fun.

Well, why not? -- Just pay a little attention if you are going to
conncect the unbalanced Akai to the balanced mixing console: this
should be made via insulating transformers (if no unbalanced
connections are provided of course).

>
>Peter
>
>
>How has that Bora been lately?

Oh the Bora wind :)) -- It has been blowing for some days recently,
sweeping the summer heat and dirt away. Nowadays after it, it's a
very fine weather. I like it. Now you can peacefully sit atop a quay
with a fishing rod in a calm sunset and take a bit of rest.

Edi Zubovic, Crikvenica, Croatia

[Peter Larsen]

Arny Krueger wrote:

> Of course, erase heads don't matter that much unless you are
> re-recording a previously-used tape.

They matter as much as any other part of the transport because the tape
travels across them just prior to record and playback heads. The price
for the machine was however right, and the GX heads are very long lived,
so it should be possible to get it in working order.

The danish ReVox importer made worse damage to my A77 in 1974 when
fitting a 15 ips capstan shaft than what you see on these pictures,
unfortunately it was 1999 before I understood just what it was that was
wrong with the transport and why its 15 kHz stability was poor ....
capstan not at 90 degrees to the tape transport plane .... :-(


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Arny Krueger wrote:

> Of course, erase heads don't matter that much unless you are
> re-recording a previously-used tape.

They matter as much as any other part of the transport because the tape
travels across them just prior to record and playback heads. The price
for the machine was however right, and the GX heads are very long lived,
so it should be possible to get it in working order.

The danish ReVox importer made worse damage to my A77 in 1974 when
fitting a 15 ips capstan shaft than what you see on these pictures,
unfortunately it was 1999 before I understood just what it was that was
wrong with the transport and why its 15 kHz stability was poor ....
capstan not at 90 degrees to the tape transport plane .... :-(


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Daniel wrote:

> Yeah, I think so too .... Thanks ....... Funny thing is that
> the machine still sounds better than my cd player ......

Aha ... well, you see this is in all likelyhood primarity because single
suply transistor circuitry, as is probable in the tape deck in question,
tends to sound better than split supply IC circuitry with poor opamps
and unbiased coupling caps.

> Daniel


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Daniel wrote:

> Yeah, I think so too .... Thanks ....... Funny thing is that
> the machine still sounds better than my cd player ......

Aha ... well, you see this is in all likelyhood primarity because single
suply transistor circuitry, as is probable in the tape deck in question,
tends to sound better than split supply IC circuitry with poor opamps
and unbiased coupling caps.

> Daniel


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Don Pearce wrote:

>> Yeah, I think so too .... Thanks ....... Funny thing is that
>> the machine still sounds better than my cd player ......

> Time for a visit to the audiologist... ;-)

Fixing what is wrong with the CD player or replacing it comes to mind
..... btw. it might not even be the player that is faulty. Not all CD's
sound as pleasant as "new technology" might seem to warrant.

> d


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Don Pearce wrote:

>> Yeah, I think so too .... Thanks ....... Funny thing is that
>> the machine still sounds better than my cd player ......

> Time for a visit to the audiologist... ;-)

Fixing what is wrong with the CD player or replacing it comes to mind
..... btw. it might not even be the player that is faulty. Not all CD's
sound as pleasant as "new technology" might seem to warrant.

> d


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Arny Krueger wrote:

>> This tape deck can sound better than a CD indeed <g>.

> Better sounding perhaps, but unlike good digital not identical.

"identical" ceases to apply on the way through the DA converter.


Kind regards

Peter Larsen
--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Arny Krueger wrote:

>> This tape deck can sound better than a CD indeed <g>.

> Better sounding perhaps, but unlike good digital not identical.

"identical" ceases to apply on the way through the DA converter.


Kind regards

Peter Larsen
--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Scott Dorsey]

Peter Larsen > wrote:
>The danish ReVox importer made worse damage to my A77 in 1974 when
>fitting a 15 ips capstan shaft than what you see on these pictures,
>unfortunately it was 1999 before I understood just what it was that was
>wrong with the transport and why its 15 kHz stability was poor ....
>capstan not at 90 degrees to the tape transport plane .... :-(

I hope you sent them a letter of complaint 15 years after the fact. The
motor kit comes with a bag of shim washers and you're supposed to shim
the motor straight specifically to prevent this. Sounds like somebody was
not reading the manual.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Peter Larsen > wrote:
>The danish ReVox importer made worse damage to my A77 in 1974 when
>fitting a 15 ips capstan shaft than what you see on these pictures,
>unfortunately it was 1999 before I understood just what it was that was
>wrong with the transport and why its 15 kHz stability was poor ....
>capstan not at 90 degrees to the tape transport plane .... :-(

I hope you sent them a letter of complaint 15 years after the fact. The
motor kit comes with a bag of shim washers and you're supposed to shim
the motor straight specifically to prevent this. Sounds like somebody was
not reading the manual.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Edi Zubovic]

On Sun, 03 Oct 2004 13:01:33 +0200, Peter Larsen
> wrote:

--------8<---------------
>The danish ReVox importer made worse damage to my A77 in 1974 when
>fitting a 15 ips capstan shaft than what you see on these pictures,
>unfortunately it was 1999 before I understood just what it was that was
>wrong with the transport and why its 15 kHz stability was poor ....
>capstan not at 90 degrees to the tape transport plane .... :-(
>
>
> Kind regards
>
> Peter Larsen

-- For a (very) so-la-la reproduction of a 15 ips tape, I have a
coressponding capstan which I can change on my Revox B77 Dolby. But,
the tape transport is quite disturbed, the pressure at the capstan
seems increased, yes the capstan is not at 90 deg., and the tape is
not touching that righthand tape guide (that one with synthetic ruby
washers). The HighSpeed Revox A and B77 models, PR99 etc. had their
entire capstan motors mounted tilted in comparison to the 3 1/4 -- 7
1/2 models. The bolt holes at the mounting plate are offest a little.
If this isn't bothering, the playback electronics still made for the
tape speed of 7 1/2 is... And I'd never record with such a capstan
mounted to this machine The result would be quite poor for an Revox :)

Edi Zubovic, Crikvenica, Croatia

[Edi Zubovic]

On Sun, 03 Oct 2004 13:01:33 +0200, Peter Larsen
> wrote:

--------8<---------------
>The danish ReVox importer made worse damage to my A77 in 1974 when
>fitting a 15 ips capstan shaft than what you see on these pictures,
>unfortunately it was 1999 before I understood just what it was that was
>wrong with the transport and why its 15 kHz stability was poor ....
>capstan not at 90 degrees to the tape transport plane .... :-(
>
>
> Kind regards
>
> Peter Larsen

-- For a (very) so-la-la reproduction of a 15 ips tape, I have a
coressponding capstan which I can change on my Revox B77 Dolby. But,
the tape transport is quite disturbed, the pressure at the capstan
seems increased, yes the capstan is not at 90 deg., and the tape is
not touching that righthand tape guide (that one with synthetic ruby
washers). The HighSpeed Revox A and B77 models, PR99 etc. had their
entire capstan motors mounted tilted in comparison to the 3 1/4 -- 7
1/2 models. The bolt holes at the mounting plate are offest a little.
If this isn't bothering, the playback electronics still made for the
tape speed of 7 1/2 is... And I'd never record with such a capstan
mounted to this machine The result would be quite poor for an Revox :)

Edi Zubovic, Crikvenica, Croatia

[Peter Larsen]

Edi Zubovic wrote:

> washers). The HighSpeed Revox A and B77 models, PR99 etc. had their
> entire capstan motors mounted tilted in comparison to the 3 1/4 -- 7
> 1/2 models.

The tilt is sideways, i.e. in the longitudinal direction of the tape. I
discovered it because a tape that had gotten a wee bit too much silicone
oil in cleaning traveled sideways.

The guy who drilled the new hole for the larger capstan must have done
it freehand. And he knew ... I wondered then why the rubber roller arm
had been obviously bent and replaced it with a new one, thinking no more
of it. I discussed it with some people back then, and nobody came up
with the idea that the rubber roller arm might have been bent so as to
get the roller parallel with the tilted capstan.

> The bolt holes at the mounting plate are offest a little.
> If this isn't bothering, the playback electronics still made for the
> tape speed of 7 1/2 is...

Not anymore, not since 1977, the so called Radio & Television
modifications (x) have all been implemented and playback electronics
have been properly matched to the actual heads.

(x) swedish magazine that had a series of articles about how to fix all
that ails a ReVox A77 ex works.

> And I'd never record with such a capstan
> mounted to this machine

Nor would I. But the machine was - and is - not a bad machine, but it is
a baaad machine to play marginal backcoated tapes on.

> The result would be quite poor for an Revox :)

Hmm ... yes, I had abandoned any thought of making another analog tape
recording by the time I found the problem, the ampex problem hit me real
hard - if only I had used more Fuji tapes ..... they sounded better, but
I was worried they would not last. Eventually they do run in to
problems, just like the 368 the appear to be a clone of, but way less
than ampex, and in fact also less than Agfa ... at least guesstimated on
the tapes I own.

I got me a G36 as a supplementary machine a couple of years ago, but the
mains power safety relay cut out when I connected it to grounded preamp
..... I wonder if all it needs is to be left powered up for the caps to
reform ... but I don't feel well about leaving a known imperfect mains
powered contraption powered up.

> Edi Zubovic, Crikvenica, Croatia


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Edi Zubovic wrote:

> washers). The HighSpeed Revox A and B77 models, PR99 etc. had their
> entire capstan motors mounted tilted in comparison to the 3 1/4 -- 7
> 1/2 models.

The tilt is sideways, i.e. in the longitudinal direction of the tape. I
discovered it because a tape that had gotten a wee bit too much silicone
oil in cleaning traveled sideways.

The guy who drilled the new hole for the larger capstan must have done
it freehand. And he knew ... I wondered then why the rubber roller arm
had been obviously bent and replaced it with a new one, thinking no more
of it. I discussed it with some people back then, and nobody came up
with the idea that the rubber roller arm might have been bent so as to
get the roller parallel with the tilted capstan.

> The bolt holes at the mounting plate are offest a little.
> If this isn't bothering, the playback electronics still made for the
> tape speed of 7 1/2 is...

Not anymore, not since 1977, the so called Radio & Television
modifications (x) have all been implemented and playback electronics
have been properly matched to the actual heads.

(x) swedish magazine that had a series of articles about how to fix all
that ails a ReVox A77 ex works.

> And I'd never record with such a capstan
> mounted to this machine

Nor would I. But the machine was - and is - not a bad machine, but it is
a baaad machine to play marginal backcoated tapes on.

> The result would be quite poor for an Revox :)

Hmm ... yes, I had abandoned any thought of making another analog tape
recording by the time I found the problem, the ampex problem hit me real
hard - if only I had used more Fuji tapes ..... they sounded better, but
I was worried they would not last. Eventually they do run in to
problems, just like the 368 the appear to be a clone of, but way less
than ampex, and in fact also less than Agfa ... at least guesstimated on
the tapes I own.

I got me a G36 as a supplementary machine a couple of years ago, but the
mains power safety relay cut out when I connected it to grounded preamp
..... I wonder if all it needs is to be left powered up for the caps to
reform ... but I don't feel well about leaving a known imperfect mains
powered contraption powered up.

> Edi Zubovic, Crikvenica, Croatia


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Scott Dorsey wrote:

> Peter Larsen > wrote:

> >The danish ReVox importer made worse damage to my A77 in 1974 when
> >fitting a 15 ips capstan shaft than what you see on these pictures,
> >unfortunately it was 1999 before I understood just what it was that was
> >wrong with the transport and why its 15 kHz stability was poor ....
> >capstan not at 90 degrees to the tape transport plane .... :-(

> I hope you sent them a letter of complaint 15 years after the fact. The
> motor kit comes with a bag of shim washers and you're supposed to shim
> the motor straight specifically to prevent this. Sounds like somebody was
> not reading the manual.

Somebody was indeed very incompetent. I tried looking the importer up,
they appear to be out of business. Reminds me ... there are still tapes
that need digitizing.

> --scott


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Scott Dorsey wrote:

> Peter Larsen > wrote:

> >The danish ReVox importer made worse damage to my A77 in 1974 when
> >fitting a 15 ips capstan shaft than what you see on these pictures,
> >unfortunately it was 1999 before I understood just what it was that was
> >wrong with the transport and why its 15 kHz stability was poor ....
> >capstan not at 90 degrees to the tape transport plane .... :-(

> I hope you sent them a letter of complaint 15 years after the fact. The
> motor kit comes with a bag of shim washers and you're supposed to shim
> the motor straight specifically to prevent this. Sounds like somebody was
> not reading the manual.

Somebody was indeed very incompetent. I tried looking the importer up,
they appear to be out of business. Reminds me ... there are still tapes
that need digitizing.

> --scott


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Edi Zubovic]

On Mon, 04 Oct 2004 07:32:25 +0200, Peter Larsen
> wrote:

--------------8<----------------------
>Not anymore, not since 1977, the so called Radio & Television
>modifications (x) have all been implemented and playback electronics
>have been properly matched to the actual heads.
>
>(x) swedish magazine that had a series of articles about how to fix all
>that ails a ReVox A77 ex works.
Oh, so then :)
>> And I'd never record with such a capstan
>> mounted to this machine
>
>Nor would I. But the machine was - and is - not a bad machine, but it is
>a baaad machine to play marginal backcoated tapes on.
>
>> The result would be quite poor for an Revox :)
>
>Hmm ... yes, I had abandoned any thought of making another analog tape
>recording by the time I found the problem, the ampex problem hit me real
>hard - if only I had used more Fuji tapes ..... they sounded better, but
>I was worried they would not last. Eventually they do run in to
>problems, just like the 368 the appear to be a clone of, but way less
>than ampex, and in fact also less than Agfa ... at least guesstimated on
>the tapes I own.-
- I'll try to find some more of BASF remnants -- namely LGR 50 MK1
pancakes. I still have some 5 of them fresh in nylon bags. They're 30
cm but go fine with Revox and this broadcast tape has indeed been a
cake literally; excellent and very forgiving about levels, it soft
saturates prior to clipping. -- It goes fine with a Revox and it
doesn't feed itself with heads like broadcast Agfas used to do... but
Ampex (no Quantegy yet; old stock) 407, which are still obtainable to
me here, are also quite fair with Revox.
>I got me a G36 as a supplementary machine a couple of years ago, but the
>mains power safety relay cut out when I connected it to grounded preamp
>.... I wonder if all it needs is to be left powered up for the caps to
>reform ... but I don't feel well about leaving a known imperfect mains
>powered contraption powered up.
If such a machine is to be powered up after decades, it is best done
with an autotransformer I think. I had a bit of luck when I tried to
start the Revox after a really long time. Its transformer has been
shortcircuited for a while until the power capacitors formed... not a
pretty picture (and smell). Everything went fine at the end though...
but in your case, when the safety relay responded, I think there must
have been a difference in earth potential and this is something asking
for 1:1 transformers or similar isolation to be 100% sure... Revox are
I think nulled; they have only two-prong power plugs and no other
ground.
>
>
>
> Kind regards
>
> Peter Larsen

Edi Zubovic, Crikvenica, Croatia

[Edi Zubovic]

On Mon, 04 Oct 2004 07:32:25 +0200, Peter Larsen
> wrote:

--------------8<----------------------
>Not anymore, not since 1977, the so called Radio & Television
>modifications (x) have all been implemented and playback electronics
>have been properly matched to the actual heads.
>
>(x) swedish magazine that had a series of articles about how to fix all
>that ails a ReVox A77 ex works.
Oh, so then :)
>> And I'd never record with such a capstan
>> mounted to this machine
>
>Nor would I. But the machine was - and is - not a bad machine, but it is
>a baaad machine to play marginal backcoated tapes on.
>
>> The result would be quite poor for an Revox :)
>
>Hmm ... yes, I had abandoned any thought of making another analog tape
>recording by the time I found the problem, the ampex problem hit me real
>hard - if only I had used more Fuji tapes ..... they sounded better, but
>I was worried they would not last. Eventually they do run in to
>problems, just like the 368 the appear to be a clone of, but way less
>than ampex, and in fact also less than Agfa ... at least guesstimated on
>the tapes I own.-
- I'll try to find some more of BASF remnants -- namely LGR 50 MK1
pancakes. I still have some 5 of them fresh in nylon bags. They're 30
cm but go fine with Revox and this broadcast tape has indeed been a
cake literally; excellent and very forgiving about levels, it soft
saturates prior to clipping. -- It goes fine with a Revox and it
doesn't feed itself with heads like broadcast Agfas used to do... but
Ampex (no Quantegy yet; old stock) 407, which are still obtainable to
me here, are also quite fair with Revox.
>I got me a G36 as a supplementary machine a couple of years ago, but the
>mains power safety relay cut out when I connected it to grounded preamp
>.... I wonder if all it needs is to be left powered up for the caps to
>reform ... but I don't feel well about leaving a known imperfect mains
>powered contraption powered up.
If such a machine is to be powered up after decades, it is best done
with an autotransformer I think. I had a bit of luck when I tried to
start the Revox after a really long time. Its transformer has been
shortcircuited for a while until the power capacitors formed... not a
pretty picture (and smell). Everything went fine at the end though...
but in your case, when the safety relay responded, I think there must
have been a difference in earth potential and this is something asking
for 1:1 transformers or similar isolation to be 100% sure... Revox are
I think nulled; they have only two-prong power plugs and no other
ground.
>
>
>
> Kind regards
>
> Peter Larsen

Edi Zubovic, Crikvenica, Croatia

[Peter Larsen]

Edi Zubovic wrote:

[ lotsa great stuff omitted]

>> I got me a G36 as a supplementary machine a couple of years ago,
>> but the mains power safety relay cut out when I connected it
>> to grounded preamp ... I wonder if all it needs is to be left
>> powered up for the caps to reform ... but I don't feel well
>> about leaving a known imperfect mains powered contraption
>> powered up.

> If such a machine is to be powered up after decades,
> it is best done with an autotransformer I think.

Such a contraption is inching its way into my wishlist.

> I had a bit of luck when I tried to start the Revox
> after a really long time.

Unused items should occasionally be left powered up for an extented
period of time, i.e. multiple days.

> Its transformer has been shortcircuited for a while until
> the power capacitors formed... not a pretty picture (and smell).
> Everything went fine at the end though... but in your case, when
> the safety relay responded,

Leak to ground relay .... checks the diff between outgoing amperage and
return.

> I think there must have been a difference in earth potential
> and this is something asking for 1:1 transformers

I have a pair of those, but they are sitting in a plastic box with one
side's winding in series between left and right, with a source
resistance in the 1 to 2 kOhm range they form an excellent VLF mono
combiner and they have occasionally done wonders to problematic
recordings back in the analog age.

> or similar isolation to be 100% sure... Revox are I think nulled;
> they have only two-prong power plugs and no other ground.

Arne E. Jensens hypothesis was that what ails it is leak current in a
coupling cap in the signal path .... in which case perhaps it really is
only about leaving it powered up for a week instead of only a day. It is
a hybrid btw. - it has been a langue lab machine and has since had the
valve playback electronics replaced, probably with a board that I know
was designed by someone who replaced all signal electronics in their
A700's, 553x is socketed ....

As for the grounding ... we run two pronged here in Denmark, but
grounding is an unavoidable property of an antenna system that is common
to all apartments in a building.

> Edi Zubovic, Crikvenica, Croatia


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Peter Larsen]

Edi Zubovic wrote:

[ lotsa great stuff omitted]

>> I got me a G36 as a supplementary machine a couple of years ago,
>> but the mains power safety relay cut out when I connected it
>> to grounded preamp ... I wonder if all it needs is to be left
>> powered up for the caps to reform ... but I don't feel well
>> about leaving a known imperfect mains powered contraption
>> powered up.

> If such a machine is to be powered up after decades,
> it is best done with an autotransformer I think.

Such a contraption is inching its way into my wishlist.

> I had a bit of luck when I tried to start the Revox
> after a really long time.

Unused items should occasionally be left powered up for an extented
period of time, i.e. multiple days.

> Its transformer has been shortcircuited for a while until
> the power capacitors formed... not a pretty picture (and smell).
> Everything went fine at the end though... but in your case, when
> the safety relay responded,

Leak to ground relay .... checks the diff between outgoing amperage and
return.

> I think there must have been a difference in earth potential
> and this is something asking for 1:1 transformers

I have a pair of those, but they are sitting in a plastic box with one
side's winding in series between left and right, with a source
resistance in the 1 to 2 kOhm range they form an excellent VLF mono
combiner and they have occasionally done wonders to problematic
recordings back in the analog age.

> or similar isolation to be 100% sure... Revox are I think nulled;
> they have only two-prong power plugs and no other ground.

Arne E. Jensens hypothesis was that what ails it is leak current in a
coupling cap in the signal path .... in which case perhaps it really is
only about leaving it powered up for a week instead of only a day. It is
a hybrid btw. - it has been a langue lab machine and has since had the
valve playback electronics replaced, probably with a board that I know
was designed by someone who replaced all signal electronics in their
A700's, 553x is socketed ....

As for the grounding ... we run two pronged here in Denmark, but
grounding is an unavoidable property of an antenna system that is common
to all apartments in a building.

> Edi Zubovic, Crikvenica, Croatia


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************

[Scott Dorsey]

Peter Larsen > wrote:
>Edi Zubovic wrote:
>
>[ lotsa great stuff omitted]
>
>>> I got me a G36 as a supplementary machine a couple of years ago,
>>> but the mains power safety relay cut out when I connected it
>>> to grounded preamp ... I wonder if all it needs is to be left
>>> powered up for the caps to reform ... but I don't feel well
>>> about leaving a known imperfect mains powered contraption
>>> powered up.
>
>> If such a machine is to be powered up after decades,
>> it is best done with an autotransformer I think.
>
>Such a contraption is inching its way into my wishlist.

It is worth having. In the meantime, a lamp board with a number of 60W
bulbs in parallel with switches will allow you to provide a voltage drop
to an appliance and allow you to bring up up slowly over the course of a
few hourse.

My personal feeling about cap reforming is that if capacitors have deformed
in storage, they should really be replaced anyway and bringing the gear up
slowly just helps you avoid replacing something that should be replaced. But
I realize this is a religious issue.

All of the A77 machines I have used had some amount of ground leakage, and
I don't honestly know why. But I would look at the primary of the power
transformer and look for filtering there that might be leaking, or for
leakage through the transformer.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Peter Larsen > wrote:
>Edi Zubovic wrote:
>
>[ lotsa great stuff omitted]
>
>>> I got me a G36 as a supplementary machine a couple of years ago,
>>> but the mains power safety relay cut out when I connected it
>>> to grounded preamp ... I wonder if all it needs is to be left
>>> powered up for the caps to reform ... but I don't feel well
>>> about leaving a known imperfect mains powered contraption
>>> powered up.
>
>> If such a machine is to be powered up after decades,
>> it is best done with an autotransformer I think.
>
>Such a contraption is inching its way into my wishlist.

It is worth having. In the meantime, a lamp board with a number of 60W
bulbs in parallel with switches will allow you to provide a voltage drop
to an appliance and allow you to bring up up slowly over the course of a
few hourse.

My personal feeling about cap reforming is that if capacitors have deformed
in storage, they should really be replaced anyway and bringing the gear up
slowly just helps you avoid replacing something that should be replaced. But
I realize this is a religious issue.

All of the A77 machines I have used had some amount of ground leakage, and
I don't honestly know why. But I would look at the primary of the power
transformer and look for filtering there that might be leaking, or for
leakage through the transformer.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Peter Larsen]

Scott Dorsey wrote:

>>> If such a machine is to be powered up after decades,
>>> it is best done with an autotransformer I think.

> >Such a contraption is inching its way into my wishlist.

> It is worth having. In the meantime, a lamp board with a
> number of 60W bulbs in parallel with switches ....

Hmmm .... we run 230 volts over here, I think I'll look into getting the
trafo - it is simpler, thanks.



Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************