I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

If -6 or -9, how did you get there? I am experimenting with changing
some resistor values to get where I want, but I'm curious what other
people have done.

Thank You,
Dennis

In article writes:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

What "MRL" are you using? And how are you converting to 8-track?

I have a feeling that you aren't starting your alignment from the
beginning, and don't really understand what you're doing, but I can't
tell for sure from your brief message.

Spill the beans. Exactly what are you doing and how are you doing it?


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

What "MRL" are you using? And how are you converting to 8-track?

I have a feeling that you aren't starting your alignment from the
beginning, and don't really understand what you're doing, but I can't
tell for sure from your brief message.

Spill the beans. Exactly what are you doing and how are you doing it?


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Mike,

If you are not already familiar with this set-up I don't think you'll
be able to help.

I am using a custom head set that has 8 'giant' tracks, along with a
'regular' size track for TC (therefore, even though it is technically
9 tracks, it is really just used as an 8 track).

Specifically, the levels off of the MRL are extremely hot now because
of the large head cores. It is fairly typical to run a +6 alignment,
but I know some guys using a +9 for this head type. I am having
trouble getting the levels down that low. In fact, there is no way to
get down to +9 at all.

Even more troublesome is that I don't have enough range on the bias
adjustments of the individual cards.

Unfortunately, I haven't found someone using the heads on an A800, so
the problems I'm having do not necessarily come into play with
something else, like an 827 as an example.

If anyone out there is doing this on an 800 and has had similar
results please let me know.

Dennis

(Mike Rivers) wrote in message news:znr1094644253k@trad...
In article writes:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

What "MRL" are you using? And how are you converting to 8-track?

I have a feeling that you aren't starting your alignment from the
beginning, and don't really understand what you're doing, but I can't
tell for sure from your brief message.

Spill the beans. Exactly what are you doing and how are you doing it?

DennisD wrote:

Unfortunately, I haven't found someone using the heads on an A800, so
the problems I'm having do not necessarily come into play with
something else, like an 827 as an example.

If anyone out there is doing this on an 800 and has had similar
results please let me know.

Contact Fletcher at Mercenary Audio in Boston, who was a point man for
the 2" 8 track on an A800 concept when he put one together for Ozzie or
somebody else famous. There was RAP discussion of this years ago, so
Google might also help.

--
ha

DennisD wrote:

If you are not already familiar with this set-up I don't think you'll
be able to help.

I am using a custom head set that has 8 'giant' tracks, along with a
'regular' size track for TC (therefore, even though it is technically
9 tracks, it is really just used as an 8 track).

This is a headstack from JRF, right?

Specifically, the levels off of the MRL are extremely hot now because
of the large head cores. It is fairly typical to run a +6 alignment,
but I know some guys using a +9 for this head type. I am having
trouble getting the levels down that low. In fact, there is no way to
get down to +9 at all.

This is a playback issue. You probably want heads with lower impedance.
The alternative is to modify the playback amps to have lower gain, which
should be a matter of a feedback resistor change or two on the front end.
I would suggest doing this rather than padding down the input to the playback
amp.

It's not hot because of the large cores, it's because of the number of
turns of wire on the cores.

Even more troublesome is that I don't have enough range on the bias
adjustments of the individual cards.

This is bad. Will it not go up enough, or will it not go down enough?
Can you get the bias trap to null out? If the bias trap will not null
out, you definitely have the wrong record head inductance.

Unfortunately, I haven't found someone using the heads on an A800, so
the problems I'm having do not necessarily come into play with
something else, like an 827 as an example.

If anyone out there is doing this on an 800 and has had similar
results please let me know.

Have you contacted JRF?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article writes:

If you are not already familiar with this set-up I don't think you'll
be able to help.

I've never worked with one, but I'm familiar with the concept.

I am using a custom head set that has 8 'giant' tracks, along with a
'regular' size track for TC (therefore, even though it is technically
9 tracks, it is really just used as an 8 track).

Specifically, the levels off of the MRL are extremely hot now because
of the large head cores. It is fairly typical to run a +6 alignment,
but I know some guys using a +9 for this head type. I am having
trouble getting the levels down that low. In fact, there is no way to
get down to +9 at all.

I'd talk to Jay McKnight at MRL and ask his advice. By the way, for
those of us struggling to remember the URL, Jay has finally sprung for
one of his own http://www.mrltapes.com

You may need a calibration tape recorded at a lower fluxivity level
than the one you have. But reference fluxivity is reference fluxivity,
and if you want to record at a given level, the electronics needs to
have the range to accommodate the level coming from the heads. The
electronics may need modification to reduce the gain.

Even more troublesome is that I don't have enough range on the bias
adjustments of the individual cards.

I hate to be one of those people who asks "Who did this modification?"
but who did this modification? Heads like that don't grow on trees
(and I don't expect they show up on eBay) so even if you mounted them
yourself, you must have purchased them from someone who has done this
conversion before. I know that when Mike Spitz or John French does a
2" 8-track conversion they don't just send you a new set of heads,
they work the machine over pretty well. Mike (ATR Service) even has
new electronics available for his Ampex conversions.

While I don't know that you'll find someone who has made the same
conversion you have, you'll find people who know the Studer
electronics well on the Studer mailing list. If you're already there
and haven't found the help you need, I don't where to turn next other
than to Studer, MRL, or whoever built the heads for you. You'll find a
link to the Studer list at http://www.recordist.com/



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Are you using a full band MRL which may be giving you too much level due to
crosstalk. See if you can find an 8 track 2" MRL.

Rail
--
Recording Engineer/Software Developer
Rail Jon Rogut Software
http://www.railjonrogut.com


"DennisD" wrote in message
om...
Mike,

If you are not already familiar with this set-up I don't think you'll
be able to help.

I am using a custom head set that has 8 'giant' tracks, along with a
'regular' size track for TC (therefore, even though it is technically
9 tracks, it is really just used as an 8 track).

Specifically, the levels off of the MRL are extremely hot now because
of the large head cores. It is fairly typical to run a +6 alignment,
but I know some guys using a +9 for this head type. I am having
trouble getting the levels down that low. In fact, there is no way to
get down to +9 at all.

Even more troublesome is that I don't have enough range on the bias
adjustments of the individual cards.

Unfortunately, I haven't found someone using the heads on an A800, so
the problems I'm having do not necessarily come into play with
something else, like an 827 as an example.

If anyone out there is doing this on an 800 and has had similar
results please let me know.

Dennis

(Mike Rivers) wrote in message
news:znr1094644253k@trad...
In article
writes:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

What "MRL" are you using? And how are you converting to 8-track?

I have a feeling that you aren't starting your alignment from the
beginning, and don't really understand what you're doing, but I can't
tell for sure from your brief message.

Spill the beans. Exactly what are you doing and how are you doing it?

Are you using a full band MRL which may be giving you too much level due to
crosstalk. See if you can find an 8 track 2" MRL.

Rail
--
Recording Engineer/Software Developer
Rail Jon Rogut Software
http://www.railjonrogut.com


"DennisD" wrote in message
om...
Mike,

If you are not already familiar with this set-up I don't think you'll
be able to help.

I am using a custom head set that has 8 'giant' tracks, along with a
'regular' size track for TC (therefore, even though it is technically
9 tracks, it is really just used as an 8 track).

Specifically, the levels off of the MRL are extremely hot now because
of the large head cores. It is fairly typical to run a +6 alignment,
but I know some guys using a +9 for this head type. I am having
trouble getting the levels down that low. In fact, there is no way to
get down to +9 at all.

Even more troublesome is that I don't have enough range on the bias
adjustments of the individual cards.

Unfortunately, I haven't found someone using the heads on an A800, so
the problems I'm having do not necessarily come into play with
something else, like an 827 as an example.

If anyone out there is doing this on an 800 and has had similar
results please let me know.

Dennis

(Mike Rivers) wrote in message
news:znr1094644253k@trad...
In article
writes:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

What "MRL" are you using? And how are you converting to 8-track?

I have a feeling that you aren't starting your alignment from the
beginning, and don't really understand what you're doing, but I can't
tell for sure from your brief message.

Spill the beans. Exactly what are you doing and how are you doing it?

Are you using a full band MRL which may be giving you too much level due to
crosstalk.

Fringing, actually, & particularly problematic at low frequencies.


Scott Fraser

Are you using a full band MRL which may be giving you too much level due to
crosstalk.

Fringing, actually, & particularly problematic at low frequencies.


Scott Fraser

Okay, here is some more info:

First, I will check with MRL, Inc. for advice on accuracy of the
alignment but I don't use the tapes for under 1K. As Scot mentions,
fringing is mainly a problem at the low end. The heads are supposed to
be 'hotter', so that isn't an issue. In fact, I can live with the
levels. I am able to get a good +6 on repro. Sync only gets down to a
+5 on a couple of tracks and is weak on bass, but I don't mind.

These heads did come from John French. He is putting together another
A800 8trk right now and will be able to do some tests for me and
compare results.

As of now my 2 issues a

1. I'm not too sure how significant the individual channel bias
adjustments are. If you are familiar with the Studer procedure the
channel gets set to 3dB over peak, then the master is set based on
tape...in our case 1.75 over peak. I can only get 1dB over on the
channels (the pot max clockwise), but then the master has plenty of
room to get the 1.75. I don't know if the channel adjustment is a
problem or not.

2. Erase depth isn't very good. To get the very minimum erase I have
the master set to over 6V p-p. Tuning the channels will give me about
66dB erase and tons of 'rocks' noise. After a second erase pass the
signal is then completely gone. I think this indicates the erase head
is the correct width and height, but that is for John to tell me (I
just sent him an email tonight, so I won't hear from him till
tomorrow). Does anyone have any ideas on erase issues like this?

Thank all of you for input.

Dennis

Okay, here is some more info:

First, I will check with MRL, Inc. for advice on accuracy of the
alignment but I don't use the tapes for under 1K. As Scot mentions,
fringing is mainly a problem at the low end. The heads are supposed to
be 'hotter', so that isn't an issue. In fact, I can live with the
levels. I am able to get a good +6 on repro. Sync only gets down to a
+5 on a couple of tracks and is weak on bass, but I don't mind.

These heads did come from John French. He is putting together another
A800 8trk right now and will be able to do some tests for me and
compare results.

As of now my 2 issues a

1. I'm not too sure how significant the individual channel bias
adjustments are. If you are familiar with the Studer procedure the
channel gets set to 3dB over peak, then the master is set based on
tape...in our case 1.75 over peak. I can only get 1dB over on the
channels (the pot max clockwise), but then the master has plenty of
room to get the 1.75. I don't know if the channel adjustment is a
problem or not.

2. Erase depth isn't very good. To get the very minimum erase I have
the master set to over 6V p-p. Tuning the channels will give me about
66dB erase and tons of 'rocks' noise. After a second erase pass the
signal is then completely gone. I think this indicates the erase head
is the correct width and height, but that is for John to tell me (I
just sent him an email tonight, so I won't hear from him till
tomorrow). Does anyone have any ideas on erase issues like this?

Thank all of you for input.

Dennis

DennisD wrote:
As of now my 2 issues a

1. I'm not too sure how significant the individual channel bias
adjustments are. If you are familiar with the Studer procedure the
channel gets set to 3dB over peak, then the master is set based on
tape...in our case 1.75 over peak. I can only get 1dB over on the
channels (the pot max clockwise), but then the master has plenty of
room to get the 1.75. I don't know if the channel adjustment is a
problem or not.

The amount of overbias you want depends on the kind of tape you are using.
It sounds to me like you don't have enough bias voltage to get the thing up
to proper level. You might be able to fudge it by maxing out the master
control and then doing all the bias with the channel controls, but it will
be more time consuming.

This does sound like it could be an incorrect head impedance issue, just
like the playback issues. But I would worry first about the playback
problems since until you get proper playback calibration, you cannot believe
your record calibration.

Does the bias trap control null out completely, or are you at the end of the
travel and still see some leakage? If so, you absolutely know the head
inductance is wrong (which implies the impedance is wrong).

2. Erase depth isn't very good. To get the very minimum erase I have
the master set to over 6V p-p. Tuning the channels will give me about
66dB erase and tons of 'rocks' noise. After a second erase pass the
signal is then completely gone. I think this indicates the erase head
is the correct width and height, but that is for John to tell me (I
just sent him an email tonight, so I won't hear from him till
tomorrow). Does anyone have any ideas on erase issues like this?

Your erase bias voltage is not high enough. What erase bias voltage are
these heads supposed to have? If they are high-Z, 6V is not going to be
anywhere near enough. What are the impedances and inductances of the
original heads and what are the impedances and inductances of the heads you
have fit on?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

DennisD wrote:
As of now my 2 issues a

1. I'm not too sure how significant the individual channel bias
adjustments are. If you are familiar with the Studer procedure the
channel gets set to 3dB over peak, then the master is set based on
tape...in our case 1.75 over peak. I can only get 1dB over on the
channels (the pot max clockwise), but then the master has plenty of
room to get the 1.75. I don't know if the channel adjustment is a
problem or not.

The amount of overbias you want depends on the kind of tape you are using.
It sounds to me like you don't have enough bias voltage to get the thing up
to proper level. You might be able to fudge it by maxing out the master
control and then doing all the bias with the channel controls, but it will
be more time consuming.

This does sound like it could be an incorrect head impedance issue, just
like the playback issues. But I would worry first about the playback
problems since until you get proper playback calibration, you cannot believe
your record calibration.

Does the bias trap control null out completely, or are you at the end of the
travel and still see some leakage? If so, you absolutely know the head
inductance is wrong (which implies the impedance is wrong).

2. Erase depth isn't very good. To get the very minimum erase I have
the master set to over 6V p-p. Tuning the channels will give me about
66dB erase and tons of 'rocks' noise. After a second erase pass the
signal is then completely gone. I think this indicates the erase head
is the correct width and height, but that is for John to tell me (I
just sent him an email tonight, so I won't hear from him till
tomorrow). Does anyone have any ideas on erase issues like this?

Your erase bias voltage is not high enough. What erase bias voltage are
these heads supposed to have? If they are high-Z, 6V is not going to be
anywhere near enough. What are the impedances and inductances of the
original heads and what are the impedances and inductances of the heads you
have fit on?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

DennisD wrote:

First, I will check with MRL, Inc. for advice on accuracy of the
alignment but I don't use the tapes for under 1K. As Scot mentions,
fringing is mainly a problem at the low end. The heads are supposed to
be 'hotter', so that isn't an issue. In fact, I can live with the
levels. I am able to get a good +6 on repro. Sync only gets down to a
+5 on a couple of tracks and is weak on bass, but I don't mind.

Oh yes, and what tape are you using? Have you considered trying a lower
bias tape?
--scott

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

DennisD wrote:

First, I will check with MRL, Inc. for advice on accuracy of the
alignment but I don't use the tapes for under 1K. As Scot mentions,
fringing is mainly a problem at the low end. The heads are supposed to
be 'hotter', so that isn't an issue. In fact, I can live with the
levels. I am able to get a good +6 on repro. Sync only gets down to a
+5 on a couple of tracks and is weak on bass, but I don't mind.

Oh yes, and what tape are you using? Have you considered trying a lower
bias tape?
--scott

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

(DennisD) wrote:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

If -6 or -9, how did you get there? I am experimenting with changing
some resistor values to get where I want, but I'm curious what other
people have done.

I have what sounds like the identical heads from JRF on my Studer
A800. No hardware modifications or special tapes were necessary to
calibrate; it came right up.

You do have to go through the full cal procedure with the master osc
and erase current, but I assume you did that. I'll drop John a note
and touch base with him and help get this sorted for you.

--Erik

(DennisD) wrote:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

If -6 or -9, how did you get there? I am experimenting with changing
some resistor values to get where I want, but I'm curious what other
people have done.

I have what sounds like the identical heads from JRF on my Studer
A800. No hardware modifications or special tapes were necessary to
calibrate; it came right up.

You do have to go through the full cal procedure with the master osc
and erase current, but I assume you did that. I'll drop John a note
and touch base with him and help get this sorted for you.

--Erik

Erik Gavriluk wrote:
(DennisD) wrote:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

If -6 or -9, how did you get there? I am experimenting with changing
some resistor values to get where I want, but I'm curious what other
people have done.

I have what sounds like the identical heads from JRF on my Studer
A800. No hardware modifications or special tapes were necessary to
calibrate; it came right up.

You do have to go through the full cal procedure with the master osc
and erase current, but I assume you did that. I'll drop John a note
and touch base with him and help get this sorted for you.

The fact that he cannot get the playback level calibration down far enough
makes me strongly suspect that he does not have the correct heads for an A800.

You can't do the full record cal procedure accurately without first doing
the playback cal.
--scott

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

Erik Gavriluk wrote:
(DennisD) wrote:

I am in the process of changing over a 24track to an 8track and wanted
to see if anyone has done this. On the A800 the levels off the MRL are
huge. I can't get the level down to a -6 alignment.

What levels do you align to?

If -6 or -9, how did you get there? I am experimenting with changing
some resistor values to get where I want, but I'm curious what other
people have done.

I have what sounds like the identical heads from JRF on my Studer
A800. No hardware modifications or special tapes were necessary to
calibrate; it came right up.

You do have to go through the full cal procedure with the master osc
and erase current, but I assume you did that. I'll drop John a note
and touch base with him and help get this sorted for you.

The fact that he cannot get the playback level calibration down far enough
makes me strongly suspect that he does not have the correct heads for an A800.

You can't do the full record cal procedure accurately without first doing
the playback cal.
--scott

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

Erik,

I tried to email you with no luck using the address you supplied.
Could you email me your number and I'll give you a call.
.

I had to send the heads back to John so he could tweak the erase head.
I will have it back and test it over the weekend. With any luck I'll
be okay with everything. I will post with my final results, but the
erase problem may have to do with a slight difference in 800 and 827
transports.

Someone mentioned the different MRL tapes. I'd have to look at the
charts to see if 1K is much different. I use that and 10K, so I don't
know if fringing will effect me too much. Other than some compensation
issues, there is nothing unique between tapes. The MRL is recorded as
if it were one giant track (hmmm...what would that sound like), so
there is no issue with cross-talk as someone had asked.

Again, thank you all for your comments.

Dennis DeCamillo

Erik,

I tried to email you with no luck using the address you supplied.
Could you email me your number and I'll give you a call.
.

I had to send the heads back to John so he could tweak the erase head.
I will have it back and test it over the weekend. With any luck I'll
be okay with everything. I will post with my final results, but the
erase problem may have to do with a slight difference in 800 and 827
transports.

Someone mentioned the different MRL tapes. I'd have to look at the
charts to see if 1K is much different. I use that and 10K, so I don't
know if fringing will effect me too much. Other than some compensation
issues, there is nothing unique between tapes. The MRL is recorded as
if it were one giant track (hmmm...what would that sound like), so
there is no issue with cross-talk as someone had asked.

Again, thank you all for your comments.

Dennis DeCamillo

DennisD wrote:

The MRL is recorded as if it were one giant track (hmmm...what would
that sound like), so
there is no issue with cross-talk as someone had asked.

Errrr..... doesn't that result in 'fringing' issues ? Guard band etc.... (
or absence of in this case ) . Calibration won't be accurate when
individual tracks are recorded / reproduced.

Possibly academic since you're unlikley to be sending tapes to another
studio.


Graham

DennisD wrote:

The MRL is recorded as if it were one giant track (hmmm...what would
that sound like), so
there is no issue with cross-talk as someone had asked.

Errrr..... doesn't that result in 'fringing' issues ? Guard band etc.... (
or absence of in this case ) . Calibration won't be accurate when
individual tracks are recorded / reproduced.

Possibly academic since you're unlikley to be sending tapes to another
studio.


Graham

Pooh Bear wrote:
DennisD wrote:

The MRL is recorded as if it were one giant track (hmmm...what would
that sound like), so
there is no issue with cross-talk as someone had asked.

Errrr..... doesn't that result in 'fringing' issues ? Guard band etc.... (
or absence of in this case ) . Calibration won't be accurate when
individual tracks are recorded / reproduced.

Right. This is why you cannot use the 50 Hz band for low-frequency playback
EQ. For 1 KHz and up, the ladder is fine, though.

All of the MRL tapes are done this way, and as a result you do have to handle
the low frequency EQ differently than you did with the old Ampex alignment
tapes. But this guy is still fighting with the 1 KHz level, let alone the
EQ settings.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Pooh Bear wrote:
DennisD wrote:

The MRL is recorded as if it were one giant track (hmmm...what would
that sound like), so
there is no issue with cross-talk as someone had asked.

Errrr..... doesn't that result in 'fringing' issues ? Guard band etc.... (
or absence of in this case ) . Calibration won't be accurate when
individual tracks are recorded / reproduced.

Right. This is why you cannot use the 50 Hz band for low-frequency playback
EQ. For 1 KHz and up, the ladder is fine, though.

All of the MRL tapes are done this way, and as a result you do have to handle
the low frequency EQ differently than you did with the old Ampex alignment
tapes. But this guy is still fighting with the 1 KHz level, let alone the
EQ settings.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."