[Robert Stevens]

I want to interface my Revox A77 into my Neotek. There is an unbalanced master out but it still runs quite hot for the little ole' A77.

I saw someone had posted a simple resistive circuit to do this in the past but cannot for the life of me find that post.

I have a ebtech line level shifter to go the other way, but don't want to spend $80 bucks if a couple of resistors will do the trick on the way into the A77.

Thanks,

Rob

[Mike Rivers[_2_]]

On 10/11/2016 2:57 PM, Robert Stevens wrote:
I want to interface my Revox A77 into my Neotek. There is an
unbalanced master out but it still runs quite hot for the little ole'
A77.

I saw someone had posted a simple resistive circuit to do this in the
past but cannot for the life of me find that post.

Try Rick Chinn's very useful web site:

http://www.uneeda-audio.com/pads/

If you have to go out and buy all the parts, it'll probably cost you
about $25. You can build a pad into a 1/4" phone plug or an XLR, but an
RCA plug is a little tight, so put the attenuator on the console end.
And don't forget to mark the cable so you know that it's not just an
ordinary unbalanced 1/4"-to-RCA cable.

--

For a good time, call http://mikeriversaudio.wordpress.com

[Robert Stevens]

Perfect! Thanks! The console end is a 120 pin Elco so not much room there either. But do-able probably.

[geoff]

On 12/10/2016 9:13 a.m., Mike Rivers wrote:
And don't forget to mark the cable so you know that it's not just an
ordinary unbalanced 1/4"-to-RCA cable.

Another way is to build whatever pad/adaptor., etc, into a little
die-cast box with the required connectors on each side to enable
utilisation of standard cables. Can even install a variety of in and out
connectors.

Or even into a XLRM-XLRF in-line adapter if the device is for
XLR-both-sides use.

Bonus is that no special cables needed that co uld get confusing at a
later date. Not a problem if a 'permanent' connection of course ...

geoff

[Mike Rivers[_2_]]

On 10/11/2016 4:52 PM, Robert Stevens wrote:
Perfect! Thanks! The console end is a 120 pin Elco so not much room
there either. But do-able probably.

In that case what I'd do is make a short lead coming out of the
multi-pin connector from the output you want to use, terminate it in an
in-line 1/4" jack, and use that as the console output. Or consider using
the headphone jack to feed your recorder. That has a level control that
you can use to get the the signal to the right level and you won't need
an attenuator. You can probably buy a TRS-to-2xRCA cable off the shelf.

--

For a good time, call http://mikeriversaudio.wordpress.com

[Scott Dorsey]

In article ,
Robert Stevens wrote:
Perfect! Thanks! The console end is a 120 pin Elco so not much room there either. But do-able probably.

Best to make an RCA-to-XLR cable with the pad inside the XLR. Mark it
appropriately. Then put a mating XLR on the other end of the cable to
the Elco. Or run the machine into the patchbay in a similar way.

When you do an alignment on an A77 these days, be sure to do a full sweep
test tape and make sure the meters stay steady for the whole sweep. You
can get issues from bad electrolytic coupling caps on those machines which
an alignment seems to compensate for, but it doesn't really. You'll know
it as soon as you see the sweep tone playback.
--scott

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

[JackA]

On Tuesday, October 11, 2016 at 5:44:49 PM UTC-4, Mike Rivers wrote:
On 10/11/2016 4:52 PM, Robert Stevens wrote:
Perfect! Thanks! The console end is a 120 pin Elco so not much room
there either. But do-able probably.

In that case what I'd do is make a short lead coming out of the
multi-pin connector from the output you want to use, terminate it in an
in-line 1/4" jack, and use that as the console output. Or consider using
the headphone jack to feed your recorder. That has a level control that
you can use to get the the signal to the right level and you won't need
an attenuator. You can probably buy a TRS-to-2xRCA cable off the shelf.

--

For a good time, call http://mikeriversaudio.wordpress.com

Where did the word "jack" (connector) come from? I GUESS (initially) from phone switchboards. But why "jack"?

Jack

[Mike Rivers[_2_]]

On 10/11/2016 6:12 PM, JackA wrote:
Where did the word "jack" (connector) come from?

Because if they called it a "jill" people would think that was sexist,
assuming they had sexism in the 1880s.

--

For a good time, call http://mikeriversaudio.wordpress.com

[JackA]

On Tuesday, October 11, 2016 at 7:42:08 PM UTC-4, Mike Rivers wrote:
On 10/11/2016 6:12 PM, JackA wrote:
Where did the word "jack" (connector) come from?

Because if they called it a "jill" people would think that was sexist,
assuming they had sexism in the 1880s.

Ha!

The good ol' days, when women tended to their men!!

I still think "jack" has to do with the penis. Like, the phrase, "jack-off".
Requires more investigation!

Jack

--

For a good time, call http://mikeriversaudio.wordpress.com

[Ron C[_2_]]

On 10/11/2016 7:42 PM, Mike Rivers wrote:
On 10/11/2016 6:12 PM, JackA wrote:
Where did the word "jack" (connector) come from?

Because if they called it a "jill" people would think that was sexist,
assuming they had sexism in the 1880s.

I kind of liked this one [ from Online Etymology Dictionary ] :
jack (n.) The proper name was used in Middle English for
"any common fellow," and thereafter extended to various
appliances which do the work of common servants (1570s).

==
Later...
Ron Capik
--

[Trevor]

On 12/10/2016 7:13 AM, Mike Rivers wrote:
On 10/11/2016 2:57 PM, Robert Stevens wrote:
I want to interface my Revox A77 into my Neotek. There is an
unbalanced master out but it still runs quite hot for the little ole'
A77.

I saw someone had posted a simple resistive circuit to do this in the
past but cannot for the life of me find that post.

Try Rick Chinn's very useful web site:

http://www.uneeda-audio.com/pads/

If you have to go out and buy all the parts, it'll probably cost you
about $25. You can build a pad into a 1/4" phone plug or an XLR, but an
RCA plug is a little tight,

Have made a few RCA to RCA attenuator leads. 1/8W resistors fit easily.
I far prefer to use a metal box with sockets and standard leads though.
Add a switch and you have multiple attenuation levels, or a quality pot
and have variable attenuation.

Trevor.

[Peter Irwin]

Ron C wrote:

I kind of liked this one [ from Online Etymology Dictionary ] :
jack (n.) The proper name was used in Middle English for
"any common fellow," and thereafter extended to various
appliances which do the work of common servants (1570s).

That's good for about 80% of things known as jack-something
or something-jack, but I think this case is different.
The switchboard phone jack seems to be named after its
incorporated switch which stands in the place of the
jack-knife switches in the very early switchboards.
Jack-knife seems to come from an earlier term - jack-a-leg knife
(spelling varies a lot) which in turn may come from
a pocket knife maker Jacques de Liege.

Peter
--

[PStamler]

Leaving aside all the etymology, I put 14dB pads inside my A77, back in the day, two resistors mounted to the input RCAs, with the input cable re-connected to the junction between them. I left it permanently in place, because the A77 had enough sensitivity on its line input that I could always turn up the input level control if I was recording from a consumer-level source.

Peace,
Paul

[Scott Dorsey]

PStamler wrote:
Leaving aside all the etymology, I put 14dB pads inside my A77, back in the=
day, two resistors mounted to the input RCAs, with the input cable re-conn=
ected to the junction between them. I left it permanently in place, because=
the A77 had enough sensitivity on its line input that I could always turn =
up the input level control if I was recording from a consumer-level source.

Well, if you're talking about level into the A77, you should do Steve
Graham's modification to bypass the input preamplifier stage and go into
the volume control. It is _much_ cleaner sounding for record.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Rick Ruskin]

On Tue, 11 Oct 2016 16:13:18 -0400, Mike Rivers
wrote:

On 10/11/2016 2:57 PM, Robert Stevens wrote:
I want to interface my Revox A77 into my Neotek. There is an
unbalanced master out but it still runs quite hot for the little ole'
A77.

I saw someone had posted a simple resistive circuit to do this in the
past but cannot for the life of me find that post.

Try Rick Chinn's very useful web site:

http://www.uneeda-audio.com/pads/

If you have to go out and buy all the parts, it'll probably cost you
about $25. You can build a pad into a 1/4" phone plug or an XLR, but an
RCA plug is a little tight, so put the attenuator on the console end.
And don't forget to mark the cable so you know that it's not just an
ordinary unbalanced 1/4"-to-RCA cable.

Or buy my Henry engineering Matchbox 2 that does that in either
direction. $50 + shipping from Seattle WA.


Rick Ruskin
Lion Dog Music- Seattle WA
http://liondogmusic.com

[Peter Larsen[_3_]]

On 11-10-2016 19:57, Robert Stevens wrote:

I want to interface my Revox A77 into my Neotek.
There is an unbalanced master out but it still runs
quite hot for the little ole' A77.

Get a service manual.

Since you do not need the input pcb in the ReVox as mic pre and have a
low impedance professional source that will drive 5 kOhm happily do
consider removing it and wiring the inputs directly to the record level
potentiometers.

Some recorder functionality will be lost, but you probably do not need
it and it is easy to re-insert the pcb, in case you can find it, I do
not think I would be able to.

Kind regards

Peter Larsen

[[email protected]]

On Thursday, October 13, 2016 at 12:13:11 PM UTC-4, Peter Larsen wrote:
On 11-10-2016 19:57, Robert Stevens wrote:

I want to interface my Revox A77 into my Neotek.
There is an unbalanced master out but it still runs
quite hot for the little ole' A77.

Get a service manual.

Since you do not need the input pcb in the ReVox as mic pre and have a
low impedance professional source that will drive 5 kOhm happily do
consider removing it and wiring the inputs directly to the record level
potentiometers.

Some recorder functionality will be lost, but you probably do not need
it and it is easy to re-insert the pcb, in case you can find it, I do
not think I would be able to.

Kind regards

Peter Larsen

Isn't one side of the pot essentially ground..

How do you connect the "professional source" which is likely balanced, to the the unbalanced load.

I'm not saying you can't, just asking how you did it.

Mark

[Mike Rivers[_2_]]

On 10/13/2016 3:53 PM, wrote:
How do you connect the "professional source" which is likely balanced, to the the unbalanced load.

You make an unbalanced connection. It's not a terrible thing to do
unless you have long cables and can't keep EMI out of them.

--

For a good time, call http://mikeriversaudio.wordpress.com

[Scott Dorsey]

wrote:
On Thursday, October 13, 2016 at 12:13:11 PM UTC-4, Peter Larsen wrote:
On 11-10-2016 19:57, Robert Stevens wrote:

I want to interface my Revox A77 into my Neotek.
There is an unbalanced master out but it still runs
quite hot for the little ole' A77.

Get a service manual.

Since you do not need the input pcb in the ReVox as mic pre and have a
low impedance professional source that will drive 5 kOhm happily do
consider removing it and wiring the inputs directly to the record level
potentiometers.

Some recorder functionality will be lost, but you probably do not need
it and it is easy to re-insert the pcb, in case you can find it, I do
not think I would be able to.

The late and lamented Steve Graham from WUOM posted directions on doing
that to this newsgroup. His notion was to break the loop at the pot and
put in an insert connector. Signal is taken from the mike preamp until
a 1/4 TS plug is put into the insert, then the mike preamp is disconnected
and signal is taken from the external source.

Isn't one side of the pot essentially ground..

How do you connect the "professional source" which is likely balanced, to the the unbalanced load.

By tying one leg of the source to ground and unbalancing it. If this is
an issue, use a transformer.
--scott

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

[JackA]

On Thursday, October 13, 2016 at 5:18:30 PM UTC-4, Mike Rivers wrote:
On 10/13/2016 3:53 PM, wrote:
How do you connect the "professional source" which is likely balanced, to the the unbalanced load.

You make an unbalanced connection. It's not a terrible thing to do
unless you have long cables and can't keep EMI out of them.

--

For a good time, call http://mikeriversaudio.wordpress.com

Okay, electronics joke...

I was married, you see, and this cute one with a really HOT body, I wasn't sure I could Resistor!!

Jack

[Trevor]

On 14/10/2016 6:53 AM, wrote:
On Thursday, October 13, 2016 at 12:13:11 PM UTC-4, Peter Larsen wrote:
On 11-10-2016 19:57, Robert Stevens wrote:

I want to interface my Revox A77 into my Neotek.
There is an unbalanced master out but it still runs
quite hot for the little ole' A77.

Get a service manual.

Since you do not need the input pcb in the ReVox as mic pre and have a
low impedance professional source that will drive 5 kOhm happily do
consider removing it and wiring the inputs directly to the record level
potentiometers.

Some recorder functionality will be lost, but you probably do not need
it and it is easy to re-insert the pcb, in case you can find it, I do
not think I would be able to.


Isn't one side of the pot essentially ground..

How do you connect the "professional source" which is likely balanced, to the the unbalanced load.

It was already stated above that it is unbalanced.


I'm not saying you can't, just asking how you did it.

Simply connect the cold side to earth via a resistor if necessary. Or
better yet use a transformer.

Trevor.

[Peter Larsen[_3_]]

On 13-10-2016 20:53, wrote:

On Thursday, October 13, 2016 at 12:13:11 PM UTC-4, Peter Larsen wrote:
On 11-10-2016 19:57, Robert Stevens wrote:

I want to interface my Revox A77 into my Neotek.

There is an unbalanced master out but it still runs
quite hot for the little ole' A77.

Get a service manual.

Since you do not need the input pcb in the ReVox as mic pre and have a
low impedance professional source that will drive 5 kOhm happily do
consider removing it and wiring the inputs directly to the record level
potentiometers.

Isn't one side of the pot essentially ground..

Exactly.

How do you connect the "professional source" which is likely balanced, to the
the unbalanced load.

First of all he has an unbalanced master out. Next there is standard
bal-unbal wiring.

I'm not saying you can't, just asking how you did it.

Finally - what I did - add Sennheiser TM003's in reverse. They are mic
trannys, but that is ok, because the signal levels inside the A77 are
silly low.

But for optimum fidelity: unbalance at the receiving end. Using an
unbalanced output will often also mean that two opamps stages are
bypassed, but your mileage may vary on that one.

Mark

Kind regards

Peter Larsen

[Bob Olhsson[_2_]]

On Tuesday, October 11, 2016 at 1:57:32 PM UTC-5, Robert Stevens wrote:
I want to interface my Revox A77 into my Neotek. There is an unbalanced master out but it still runs quite hot for the little ole' A77.

A-77s run everything through a really bad sounding mike preamp. Just rewire the inputs to the record level pots and you'll have arguably one of the best sounding tape recorders ever! I'm forever indebted to the Abbey Road engineers who told me about during on my visit to EMI's London studio in 1969. My A-77 still beats most!

[Mike Rivers[_2_]]

On 11/5/2016 12:09 PM, Bob Olhsson wrote:
A-77s run everything through a really bad sounding mike preamp. Just
rewire the inputs to the record level pots and you'll have arguably
one of the best sounding tape recorders ever!

Good advice, but the request was for a SIMPLE way to drop the level.
Rewiring the input stage isn't likely to be considered simple by someone
who needed to ask this question. He needs, and I hope he got, a pair of
in-line attenuators and the appropriate adapters for the connectors.



--

For a good time, call http://mikeriversaudio.wordpress.com

[Scott Dorsey]

Bob Olhsson wrote:

A-77s run everything through a really bad sounding mike preamp. Just rewire=
the inputs to the record level pots and you'll have arguably one of the be=
st sounding tape recorders ever! I'm forever indebted to the Abbey Road eng=
ineers who told me about during on my visit to EMI's London studio in 1969.=
My A-77 still beats most!

It is good to see you back, Bob! As mentioned earlier in this thread,
the late Steve Graham from WUOM who was a regular poster in this group
once posted a detailed set of modifications for doing it back in the
early 1990s. I did the modifications at the time and I can attest that
the improvement in record quality was significant.
--scott

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

[Peter Larsen[_3_]]

On 05-11-2016 23:39, Scott Dorsey wrote:
Bob Olhsson wrote:

A-77s run everything through a really bad sounding mike preamp. Just rewire=
the inputs to the record level pots and you'll have arguably one of the be=
st sounding tape recorders ever! I'm forever indebted to the Abbey Road eng=
ineers who told me about during on my visit to EMI's London studio in 1969.=
My A-77 still beats most!

It is good to see you back, Bob! As mentioned earlier in this thread,
the late Steve Graham from WUOM who was a regular poster in this group
once posted a detailed set of modifications for doing it back in the
early 1990s. I did the modifications at the time and I can attest that
the improvement in record quality was significant.

Afformative, fixing playback eq is also a good idea. It then gets
possible to align the machine to a standard rather than to just be
linear on its own.

--scott

Kind regards

Peter Larsen