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Emiliano Grilli Emiliano Grilli is offline
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Default Revox PR99 Mk III question

Hi all

I'm just trying to set up my revox pr 99 myself: I bought an alignment
tape and I've tried to follow the procedure. It seems that all is
going well... (forgive me but these are my first alignments..), I've
got a recorded signal that's pretty similar to what's on the SOURCE
signal.

The problem is that on the SOURCE I have a signal that's a lot weaker
in the low end that what is coming in.

I've not taken it apart the machine yet, but in the manual I don't see
anything referring to the eq of the input signal...

Any pointers?

thank you in advance.
--
Emiliano Grilli
Linux user #209089
http://www.emillo.net

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Paul Stamler Paul Stamler is offline
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Default Revox PR99 Mk III question

"Emiliano Grilli" wrote in message
...
Hi all

I'm just trying to set up my revox pr 99 myself: I bought an alignment
tape and I've tried to follow the procedure. It seems that all is
going well... (forgive me but these are my first alignments..), I've
got a recorded signal that's pretty similar to what's on the SOURCE
signal.

The problem is that on the SOURCE I have a signal that's a lot weaker
in the low end that what is coming in.

I've not taken it apart the machine yet, but in the manual I don't see
anything referring to the eq of the input signal...


There should not be any EQ on the input signal. How are you listening to
what's coming in, and how are you listening to what's coming out of the
Revox?

Peace,
Paul


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Ty Ford Ty Ford is offline
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Default Revox PR99 Mk III question

On Mon, 21 Jan 2008 11:19:16 -0500, Emiliano Grilli wrote
(in article
):

Hi all

I'm just trying to set up my revox pr 99 myself: I bought an alignment
tape and I've tried to follow the procedure. It seems that all is
going well... (forgive me but these are my first alignments..), I've
got a recorded signal that's pretty similar to what's on the SOURCE
signal.

The problem is that on the SOURCE I have a signal that's a lot weaker
in the low end that what is coming in.

I've not taken it apart the machine yet, but in the manual I don't see
anything referring to the eq of the input signal...

Any pointers?

thank you in advance.
--
Emiliano Grilli
Linux user #209089
http://www.emillo.net


I'm confused. Source is what's coming in.

Regards,

Ty Ford


--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=4RZJ9MptZmU

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Emiliano Grilli Emiliano Grilli is offline
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Default Revox PR99 Mk III question

On 21 Gen, 17:45, "Paul Stamler" wrote:
"Emiliano Grilli" wrote in message

...

Hi all


I'm just trying to set up my revox pr 99 myself: I bought an alignment
tape and I've tried to follow the procedure. It seems that all is
going well... (forgive me but these are my first alignments..), I've
got a recorded signal that's pretty similar to what's on the SOURCE
signal.


The problem is that on the SOURCE I have a signal that's a lot weaker
in the low end that what is coming in.


I've not taken it apart the machine yet, but in the manual I don't see
anything referring to the eq of the input signal...


There should not be any EQ on the input signal. How are you listening to
what's coming in, and how are you listening to what's coming out of the
Revox?


I have the line out of the revox connected to a stereo channel on my
soundcraft folio mixer, and the line in is taking the output of the
soundcard, which also goes to the mixer, so I can A/B the revox (both
SOURCE and REPRODUCE) and the soundcard.

Peace,
Paul


thanks

--
Emiliano Grilli
Linux user #209089
http://www.emillo.net
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Emiliano Grilli Emiliano Grilli is offline
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Default Revox PR99 Mk III question

On 21 Gen, 17:56, Ty Ford wrote:

I'm confused. Source is what's coming in.


Yes, but I have the same signal on the console, and there I hear a lot
of bass that isn't there on the deck, monitoring SOURCE.



Regards,

Ty Ford


thanks
--
Emiliano Grilli
Linux user #209089
http://www.emillo.net


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Mike Rivers Mike Rivers is offline
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Default Revox PR99 Mk III question

On Jan 21, 12:00 pm, Emiliano Grilli
wrote:

Yes, but I have the same signal on the console, and there I hear a lot
of bass that isn't there on the deck, monitoring SOURCE.


Listening tests are good, but if you're trying to solve a problem, or
determine if there's a problem and where it is, measurements are
better.

If I'm interpreting your setup correctly, you have the console output
connected to the input of your recorder and the output of the recorder
connected back into the console. You're switching (at the console)
between listening to the direct console output (as fed to the
recorder) and what's coming out of the recorder?

And you're losing bass, even with the recorder set to Input Monitor?

There's something very wrong here, either with the recorder, the
console input that you're usinjg to monitor the recorder, or the
hookup.

Proper alignment requires some references - a known, or at least fixed
(sine wave) input source and, for playback alignment, a standard test
tape. If the recorder is operating properly and it's properly
connected to your monitoring system, you can make some adjustments so
that it sounds best, but you won't know where you are in reference to
the rest of the world, and you may be making problems for yourself.

Alignment is simple, but you can't do it without test equipment. And
there's no sense in doing an alignment until you fix all the real
problems, which it appears that you have.
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Paul Stamler Paul Stamler is offline
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Default Revox PR99 Mk III question

"Emiliano Grilli" wrote in message
...
On 21 Gen, 17:45, "Paul Stamler" wrote:
The problem is that on the SOURCE I have a signal that's a lot weaker
in the low end that what is coming in.


I've not taken it apart the machine yet, but in the manual I don't see
anything referring to the eq of the input signal...


There should not be any EQ on the input signal. How are you listening to
what's coming in, and how are you listening to what's coming out of the
Revox?


I have the line out of the revox connected to a stereo channel on my
soundcraft folio mixer, and the line in is taking the output of the
soundcard, which also goes to the mixer, so I can A/B the revox (both
SOURCE and REPRODUCE) and the soundcard.


Three things. First off, how carefully are you matching the levels in the
Folio channels devoted to the soundcard and the Revox? A small difference in
level will sound like a change in bass response.

Second: Are you absolutely certain the two channels of the Folio have flat
frequency response? I don't know the board, so don't know if the EQ can be
swtiched out, but if not, have you measured to make sure the response is
really flat when the controls are set to flat?

Third: The Revox has XLR outputs; the Folio has 1/4" inputs. Exactly how are
you converting? XLR to TRS? Again, I don't know the board, so I don't know
if the stereo inputs come in on a single 1/4" "stereo" jack (tip for L, ring
for R) or a pair of them. Please tell me.

Peace,
Paul


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Emiliano Grilli Emiliano Grilli is offline
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Default Revox PR99 Mk III question

On 21 Gen, 19:08, Mike Rivers wrote:
On Jan 21, 12:00 pm, Emiliano Grilli
wrote:

Yes, but I have the same signal on the console, and there I hear a lot
of bass that isn't there on the deck, monitoring SOURCE.


Listening tests are good, but if you're trying to solve a problem, or
determine if there's a problem and where it is, measurements are
better.

If I'm interpreting your setup correctly, you have the console output
connected to the input of your recorder and the output of the recorder
connected back into the console. You're switching (at the console)
between listening to the direct console output (as fed to the
recorder) and what's coming out of the recorder?


No, the input of the recorder is connected to the output of my
soundcard thru a (cheap, sorry) patchbay that routes the soundcard
output also to the console.

And you're losing bass, even with the recorder set to Input Monitor?


Yes, it's not a loss as if you would listening to a vinyl without RIAA
eq, but there's surely a loss in the bass area.

There's something very wrong here, either with the recorder, the
console input that you're usinjg to monitor the recorder, or the
hookup.

Proper alignment requires some references - a known, or at least fixed
(sine wave) input source and, for playback alignment, a standard test
tape.


I have the test tape, and for feeding the tones I'm using sine waves
generated by csound.


If the recorder is operating properly and it's properly
connected to your monitoring system, you can make some adjustments so
that it sounds best, but you won't know where you are in reference to
the rest of the world, and you may be making problems for yourself.

Alignment is simple, but you can't do it without test equipment. And
there's no sense in doing an alignment until you fix all the real
problems, which it appears that you have.


As far as I can tell the recorder works, in the sense that it records
well what's on the SOURCE, but that signal is already degraded in bass
response...

thank you
--
Emiliano Grilli
Linux user #209089
http://www.emillo.net
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Scott Dorsey Scott Dorsey is offline
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Posts: 16,853
Default Revox PR99 Mk III question

Emiliano Grilli wrote:

I'm just trying to set up my revox pr 99 myself: I bought an alignment
tape and I've tried to follow the procedure. It seems that all is
going well... (forgive me but these are my first alignments..), I've
got a recorded signal that's pretty similar to what's on the SOURCE
signal.

The problem is that on the SOURCE I have a signal that's a lot weaker
in the low end that what is coming in.


You have bad coupling caps. If you have the monitor switch set to source,
you are listening just through the line amplifiers and not through the
tape itself or the record or play EQ. So if this is affecting your low
end, you have bad coupling caps in the line amplifier stages.

I would have a tendency just to shotgun out all of the Philips electrolytics
personally. Just because if some are bad, others will soon follow.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Emiliano Grilli Emiliano Grilli is offline
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Posts: 61
Default Revox PR99 Mk III question

On 21 Gen, 19:13, "Paul Stamler" wrote:

Third: The Revox has XLR outputs; the Folio has 1/4" inputs. Exactly how are
you converting? XLR to TRS? Again, I don't know the board, so I don't know
if the stereo inputs come in on a single 1/4" "stereo" jack (tip for L, ring
for R) or a pair of them. Please tell me.


That hint led me to the solution... I'm feeling very lame for not
being able to spot the problem by hear, but double checking the
connections I've found that the two cables connecting the revox outs
to the console were reversed in polarity

Now it's so much better. Thank you very much for helping me.

I have another question

The manual instruct me to feed the recorder with a 1 khz tone at the
"desired operating level" when calibrating the inputs.

I'm using csound for generating the tone, and the opcode ampdb (http://
mitpress.mit.edu/e-books/csound/fpage/pub/csbook/Manual4.0/valcnv/
dbamp.htm) for setting its level.

If I understand correctly this level is going to represent 0 VU on the
machine's meters, is that right?

What is considered a good value for this operating level compared with
0db digital?

Peace,
Paul


thanks
--
Emiliano Grilli
Linux user #209089
http://www.emillo.net


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Paul Stamler Paul Stamler is offline
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Posts: 1,614
Default Revox PR99 Mk III question

"Emiliano Grilli" wrote in message
...

I have another question

The manual instruct me to feed the recorder with a 1 khz tone at the
"desired operating level" when calibrating the inputs.

I'm using csound for generating the tone, and the opcode ampdb (http://
mitpress.mit.edu/e-books/csound/fpage/pub/csbook/Manual4.0/valcnv/
dbamp.htm) for setting its level.

If I understand correctly this level is going to represent 0 VU on the
machine's meters, is that right?

What is considered a good value for this operating level compared with
0db digital?


That's going to depend on your sound card and how many volts it puts out for
0dB digital, and what you're going to use the Revox for. The following
assumes that the sound card will be the source of whatever you record on the
Revox -- in other words, you're dubbing from the computer into the Revox.

Really, the issue is what kind of "nominal" level you record at. If your
*average* level is, say, -14dBFS when recording digitally (this would be the
level a VU meter would read), then that should correspond to 0 VU on the
Revox. The Revox is measuring average level, while the digital system works
only with peak levels.

If it were me, since I use -14dBFS as a nominal level in digital, I'd
generate a 1kHz tone at -14dBFS and set the Revox's nominal 0VU level to
that signal. How many actual volts that might be will, as I said, depend on
your sound card.

If, on the other hand, you'll be recording from your mixer into the Revox,
then it's probably a good idea to set the VUs for +4dBu (about 1.23V) input
level 0 VU. That's a good world standard. Do your level monitoring on the
Revox, not the mixer's LEDs.

Peace,
Paul


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Ty Ford Ty Ford is offline
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Posts: 2,287
Default Revox PR99 Mk III question

On Tue, 22 Jan 2008 13:25:14 -0500, Paul Stamler wrote
(in article ):

"Emiliano Grilli" wrote in message
...

I have another question

The manual instruct me to feed the recorder with a 1 khz tone at the
"desired operating level" when calibrating the inputs.

I'm using csound for generating the tone, and the opcode ampdb (http://
mitpress.mit.edu/e-books/csound/fpage/pub/csbook/Manual4.0/valcnv/
dbamp.htm) for setting its level.

If I understand correctly this level is going to represent 0 VU on the
machine's meters, is that right?

What is considered a good value for this operating level compared with
0db digital?


That's going to depend on your sound card and how many volts it puts out for
0dB digital, and what you're going to use the Revox for. The following
assumes that the sound card will be the source of whatever you record on the
Revox -- in other words, you're dubbing from the computer into the Revox.

Really, the issue is what kind of "nominal" level you record at. If your
*average* level is, say, -14dBFS when recording digitally (this would be the
level a VU meter would read), then that should correspond to 0 VU on the
Revox. The Revox is measuring average level, while the digital system works
only with peak levels.

If it were me, since I use -14dBFS as a nominal level in digital, I'd
generate a 1kHz tone at -14dBFS and set the Revox's nominal 0VU level to
that signal. How many actual volts that might be will, as I said, depend on
your sound card.

If, on the other hand, you'll be recording from your mixer into the Revox,
then it's probably a good idea to set the VUs for +4dBu (about 1.23V) input
level 0 VU. That's a good world standard. Do your level monitoring on the
Revox, not the mixer's LEDs.

Peace,
Paul


Just an observation. As we get farther and farther away from analog tape
recording, it becomes increasingly important to remember that there was a lot
of craft involved in setting a machine up and maintaining it.

At this point in the analog tape machine life cycle, there are fewer and
fewer people who have the experience to know how to work on the machines.

Be careful of anyone pushing analog tape technology as a great way to record.
They may not have the skills to keep their machine in spec. Then too, the
circuits in analog tape machines are getting pretty old. Unless they have
been carefully maintained down to components on the boards, they can sound
pretty nasty.

Regards,

Ty Ford




--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=4RZJ9MptZmU

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