analog tape deck directly to audio interface... what type of cables?

[ucaudio]

I want to hook up a 2 track Sony (MCI) JH110-C analog tape deck
directly to an M-Audio 1814 audio interface. 2 channels running out of
the M-Audio and into the Sony, then 2 channels running out of the Sony
and back into the M-Audio. I'm trying to make sure I get the right
cables for this. I'd also like to be able to run the 2 master xlr outs
of a studio master 16-8-2 mixer out into the Sony deck then run the
sony deck out into the M-Audio. Any info is really appreciated. I've
written out the specs for both machines below.

Here are the specs:
M-Audio Inputs:
- 8 unbalanced inputs on 1/4" TS jacks
- 2 inputs that will accept a low-impedance mic level signal on a
standard three pin balanced XLR or TRS plug or a high impedance
instrument level signal on an unbalanced 1/4" TS plug uses XLR/1/4"
hybrid jacks

M-Audio Outputs:
- 4 balanced/unbalanced outputs on 1/4" TRS jacks with signal up to
2.0dbv unbal and 8.0dbv bal

Sony deck:
"This machine conforms to the IEC 256 standards for XLR 3-type
connectors"
Sheild, Signal high, and Signal low

Sony inputs:
- 2 XLR inputs line in 12k ohms bal (printed directly on unit)
- 2 XLR outpus line out 600 ohms bal (printed directly on unit)
(as a sidenote a manual that I bought seperately states line input
impedance 10k ohms balanced, line output source impedance 100 ohms
balanced)

[Mike Rivers]

ucaudio wrote:
> I want to hook up a 2 track Sony (MCI) JH110-C analog tape deck
> directly to an M-Audio 1814 audio interface. 2 channels running out of
> the M-Audio and into the Sony, then 2 channels running out of the Sony
> and back into the M-Audio. I'm trying to make sure I get the right
> cables for this.

That's going to be a little tough unless you're prepared to make the
cable yourself, of modify a store-bought one. The problem is the
unbalanced TS input jacks on the M-Audio gadget. I'm pretty sure the
JH-110 has output transformers, so you can use a cable that has the
tip wired to Pin 2 and the sleeve wired to pins 1 and 3. Some are
built like this, some aren't, and the real problem is that chances are
your friendly local dealer won't have a clue as to what he's selling
you. Anyway, that's the hookup you need for that cable.

For the M-Audio output to the MCI input, you'll need a TRS-XLR cable
wired with the tip to pin 2, the ring to pin 3 and the sleeve to pin
1. You'll probably get lucky and be able to buy one like that off the
shelf.

> I'd also like to be able to run the 2 master xlr outs
> of a studio master 16-8-2 mixer out into the Sony deck then run the
> sony deck out into the M-Audio. Any info is really appreciated.

Standard XLR mic cables will work to connect the mixer outputs to the
MCI inputs.

[Paul Stamler]

"ucaudio" > wrote in message
oups.com...
> I want to hook up a 2 track Sony (MCI) JH110-C analog tape deck
> directly to an M-Audio 1814 audio interface. 2 channels running out of
> the M-Audio and into the Sony, then 2 channels running out of the Sony
> and back into the M-Audio. I'm trying to make sure I get the right
> cables for this. I'd also like to be able to run the 2 master xlr outs
> of a studio master 16-8-2 mixer out into the Sony deck then run the
> sony deck out into the M-Audio. Any info is really appreciated. I've
> written out the specs for both machines below.

Going from the M-Audio's out to the Sony/MCI's in is simple; you want a TRS
Male > XLR Male cable, with T > pin 2, R > pin 3, S > pin 1. Most audio
stores will have that.

Going from the Sony/MCI's out to the M-Audio's in is tougher, becauise you
need to know whether the Sony's output is electronically balanced
(transformerless) or balanced-and-floating (transformer-coupled). If it's
transformerless, you'll want to take an XLR Female > TRS Male cable, also
available at audio stores, open up the XLR connector, and snip the wire
connected to pin 3. This will put pin 2 > T and pin 1 > S, which essentially
takes one side of the electronically-balanced output, leaving the other side
unconnected.

If the Sony is transformer-balanced, though, you want to use the same cable,
but this time open up the XLR connector and solder in a jumper between pins
1 and 3. This grounds one end of the transformer's output winding, while the
other end connects to T.

Note that the first hookup (electronically balanced) will have a nominal
level of -2dBu when the Sony's meter reads 0 VU, kind of hot for the
M-Audio, which presumably expects to see -10dBV, or about -8dBu. The second
hookup (transformer-balanced) will have a nominal level of +4dBu when the
meter reads 0 VU, which is way hotter than the M-Audio wants to see. (Expect
to see peaks of up to 12dB over nominal level on recordings, maybe more.)
You may need to adjust the repro level controls on the Sony way below normal
levels to avoid clipping the dickens out of the M-Audio. Similarly, you may
need to crank the Sony's input level controls to get a decent level out of
the M-Audio's signal.

Or you could go buy a Matchbox and ignore all of the above.

Peace,
Paul
> Here are the specs:
> M-Audio Inputs:
> - 8 unbalanced inputs on 1/4" TS jacks
> - 2 inputs that will accept a low-impedance mic level signal on a
> standard three pin balanced XLR or TRS plug or a high impedance
> instrument level signal on an unbalanced 1/4" TS plug uses XLR/1/4"
> hybrid jacks
>
> M-Audio Outputs:
> - 4 balanced/unbalanced outputs on 1/4" TRS jacks with signal up to
> 2.0dbv unbal and 8.0dbv bal
>
> Sony deck:
> "This machine conforms to the IEC 256 standards for XLR 3-type
> connectors"
> Sheild, Signal high, and Signal low
>
> Sony inputs:
> - 2 XLR inputs line in 12k ohms bal (printed directly on unit)
> - 2 XLR outpus line out 600 ohms bal (printed directly on unit)
> (as a sidenote a manual that I bought seperately states line input
> impedance 10k ohms balanced, line output source impedance 100 ohms
> balanced)
>

[ucaudio]

Thanks for the info. Wow, the guy I bought this from told me I should
be able to just get 4 standard XLR to 1/4" TS cables and shouldn't
have any problems. Would you run the output of the Sony into the rear
1/4" unbal jacks on the M-Audio, or the XLR/1/4" hybrid jacks on the
front of the unit? I wonder if I will be able to find these cables
online.

[Scott Dorsey]

ucaudio > wrote:
>I want to hook up a 2 track Sony (MCI) JH110-C analog tape deck
>directly to an M-Audio 1814 audio interface. 2 channels running out of
>the M-Audio and into the Sony, then 2 channels running out of the Sony
>and back into the M-Audio. I'm trying to make sure I get the right
>cables for this. I'd also like to be able to run the 2 master xlr outs
>of a studio master 16-8-2 mixer out into the Sony deck then run the
>sony deck out into the M-Audio. Any info is really appreciated. I've
>written out the specs for both machines below.

A straight through cable is just fine. The MCI has transformer-isolated
inputs and outputs like everything of that era, so you can plug damn near
anything into it and it will be happy.

I do not recall if the MCI has a termination switch on the back like Scully
and Ampex machines do. If it does not, you will want to add a 620 ohm
shunt resistor between pins 2 and 3 of the XLR outputs so that the transformer
sees a 600 ohm load when it's going into the modern high-Z input of the
M-Audio box. A lot of equipment of that era had a switchable termination
resistor on the outputs because electronic inputs were starting to become
fashionable.
--scott

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

[Paul Stamler]

"ucaudio" > wrote in message
ups.com...
> Thanks for the info. Wow, the guy I bought this from told me I should
> be able to just get 4 standard XLR to 1/4" TS cables and shouldn't
> have any problems. Would you run the output of the Sony into the rear
> 1/4" unbal jacks on the M-Audio, or the XLR/1/4" hybrid jacks on the
> front of the unit? I wonder if I will be able to find these cables
> online.

Definitely go into the 1/4" jacks; the XLR/1/4" are for microphones and
instruments, and are too sensitive for the high line voltages of the Sony.

If you can find out whether the Sony has transformers on the outputs (the
manual should say), you can have Markertek make up the cables any way you
like (www.markertek.com). See my previous message for how to wire them.

Peace,
Paul

[ucaudio]

Mike, Paul, and Scott,, thank you all for your input on this. I want
to recap real quick and make sure I've got this right before I start
ordering cables.

M-Audio --> Sony
The general consensus seems to be that I can use standard balanced TRS
to XLR cables for this (even though the M-Audio can output balances or
unbalanced levels etc)

Sony --> M-Audio
I don't see a termination switch on the machine. Mike said "you can
use a cable that has the tip wired to Pin 2 and the sleeve wired to
pins 1 and 3." If I found a cable like this, would that effectively be
the same as if I were to use a standard XLR to TRS and place a 620 ohm
shunt resistor between pins 2 and 3 of the XLR outputs of the Sony?
Also I think Mike and Paul were suggesting using the unbalanced line
level TS input jacks on the back of the units, but Scott you mentioned
Hi-Z, the 2 front inputs of the unit accomodate Hi-Z (either XLR or
1/4" TRS). Just trying to get a clear understanding here. Thanks again
for the knowledge.

Here is a pic of the M-Audio unit:
http://digitalmedia.oreilly.com/images/oreilly/digitalmedia/2005/06/portable1_fw_1814.jpg

[Paul Stamler]

"ucaudio" > wrote in message
ps.com...
> Mike, Paul, and Scott,, thank you all for your input on this. I want
> to recap real quick and make sure I've got this right before I start
> ordering cables.
>
> M-Audio --> Sony
> The general consensus seems to be that I can use standard balanced TRS
> to XLR cables for this (even though the M-Audio can output balances or
> unbalanced levels etc)

Yep.

> Sony --> M-Audio
> I don't see a termination switch on the machine. Mike said "you can
> use a cable that has the tip wired to Pin 2 and the sleeve wired to
> pins 1 and 3." If I found a cable like this, would that effectively be
> the same as if I were to use a standard XLR to TRS and place a 620 ohm
> shunt resistor between pins 2 and 3 of the XLR outputs of the Sony?

No. If it's a transformerless output, you don't need the 620 ohm resistor
(and you'll slightly increase the distortion by using it). If it's
transformer-coupled, then the 620 ohm resistor will be useful, assuming
there's no termination switch, but you also need to wire pin 3 to pin 1
(ground). Otherwise the two ends of the transformer connect to the tip and
ring of the TRS plug, but the M-Audio box doesn't connect anything to the
ring, because it's a TS jack, so one end of the transformer secondary
remains unconnected and there is no complete circuit for the signal to flow
through.

> Also I think Mike and Paul were suggesting using the unbalanced line
> level TS input jacks on the back of the units, but Scott you mentioned
> Hi-Z, the 2 front inputs of the unit accomodate Hi-Z (either XLR or
> 1/4" TRS). Just trying to get a clear understanding here. Thanks again
> for the knowledge.

The TS jacks are also, comparatively, hi-Z. Low-Z, in this context, would be
600 ohms or so. These guys have an input Z of 10k, which is high for a
transformer-coupled output. Again, read the manual. It should tell you about
things like whether it's transformer-coupled, and whether the transformer
needs to be terminated by 600 ohms.

Peace,
Paul

[Scott Dorsey]

ucaudio > wrote:
>Sony --> M-Audio
>I don't see a termination switch on the machine. Mike said "you can
>use a cable that has the tip wired to Pin 2 and the sleeve wired to
>pins 1 and 3." If I found a cable like this, would that effectively be
>the same as if I were to use a standard XLR to TRS and place a 620 ohm
>shunt resistor between pins 2 and 3 of the XLR outputs of the Sony?
>Also I think Mike and Paul were suggesting using the unbalanced line
>level TS input jacks on the back of the units, but Scott you mentioned
>Hi-Z, the 2 front inputs of the unit accomodate Hi-Z (either XLR or
>1/4" TRS). Just trying to get a clear understanding here. Thanks again
>for the knowledge.

All inputs on everything made today pretty much are high impedance.
You do NOT want to use the mike-level inputs, you want to use the line
level inputs.

The easiest way to add the shunt resistor is to solder it into the cable
inside the XLR connector.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[ucaudio]

Alright sounds good. I'm surprised no standard cables are sold that
let you run Bal XLR into 1/4" TS in a situation like this. Looks like
I will have to hire someone to make me some cables since I don't have
a soldering iron. Might try a website like www.markertek.com.

[Scott Dorsey]

ucaudio > wrote:
>Alright sounds good. I'm surprised no standard cables are sold that
>let you run Bal XLR into 1/4" TS in a situation like this. Looks like
>I will have to hire someone to make me some cables since I don't have
>a soldering iron. Might try a website like www.markertek.com.

Markertek will make you whatever you want, and they'll even add shunt
resistors if you ask and pay for it. So will Gepco, or any of those
other custom cable guys.

But it's worth having a soldering iron and learning to use it, because
making custom cables is an ordinary fact of life, and things are getting
worse rather than better as more weird connectors and new interfaces
appear.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Geoff]

Mike Rivers wrote:
>
> That's going to be a little tough unless you're prepared to make the
> cable yourself, of modify a store-bought one. The problem is the
> unbalanced TS input jacks on the M-Audio gadget. I'm pretty sure the
> JH-110 has output transformers, so you can use a cable that has the
> tip wired to Pin 2 and the sleeve wired to pins 1 and 3. Some are
> built like this, some aren't, and the real problem is that chances are
> your friendly local dealer won't have a clue as to what he's selling
> you. Anyway, that's the hookup you need for that cable.

An XLR to mono jack lead usually (always ?) implements that. Often available
from MI shops, sometime moreso than 'real' mic leads.

>geoff

[Geoff]

ucaudio wrote:
> Thanks for the info. Wow, the guy I bought this from told me I should
> be able to just get 4 standard XLR to 1/4" TS cables and shouldn't
> have any problems.

He was right for the Sony>M-Audio bit....

geoff

[Laurence Payne]

On 1 Feb 2007 09:40:59 -0800, "ucaudio" > wrote:

>Thanks for the info. Wow, the guy I bought this from told me I should
>be able to just get 4 standard XLR to 1/4" TS cables and shouldn't
>have any problems. Would you run the output of the Sony into the rear
>1/4" unbal jacks on the M-Audio, or the XLR/1/4" hybrid jacks on the
>front of the unit? I wonder if I will be able to find these cables
>online.

Don't bother. This is where you buy a soldering iron and learn a
very necessary skill. You've just described perfectly why it IS
necessary for you :-)

[ucaudio]

Geoff, so you're saying that I should be fine with the setup below?

M-Audio --> Sony
- standard 1/4" TRS to XLR

Sony --> M-Audio
- standard XLR to 1/4" TS

as far as if there are transformers in this JH10-C deck I'm not
finding any mention of them in the manual. The manual does say the I/O
Amplifier Board containes balanced amplifiers for the line inoput and
line output signals. Also, on the record and repro mode block diagrams
I'm not seeing anything that looks like a transformer symbol.

[Geoff]

ucaudio wrote:
> Geoff, so you're saying that I should be fine with the setup below?
>
> M-Audio --> Sony
> - standard 1/4" TRS to XLR

Maybe, depending on the nature of the Sony XLR input.

> Sony --> M-Audio
> - standard XLR to 1/4" TS

Yes, assuming the info that the Sony has transformer-coupled outputs is
correct. And 'probably' even if not, depending on the nature of the M-Audio
outputs.

Sorry, I can't be more concise than that. Other posters may be.

However try it and see - there is little chance of damaging anything.

geoff

[Mike Rivers]

Geoff wrote:

> An XLR to mono jack lead usually (always ?) implements that. Often available
> from MI shops, sometime moreso than 'real' mic leads.

Almost always . . . except for the one someone buys that you can't see
and he can't either.

[Mike Rivers]

ucaudio wrote:
> Would you run the output of the Sony into the rear
> 1/4" unbal jacks on the M-Audio, or the XLR/1/4" hybrid jacks on the
> front of the unit?

The XLR/1/4" jacks are probalby for mic level on the XLR and
instrument level high impedance on the 1/4" part. Neither would be
appropriate.

Paul gave you the long story about different output configurations. I
just gave you the warning that you may have to figure this out when
you start hooking things up.

Can you solder, or do you have a friend who can? If so, get "standard"
XLR-TRS cables (remember that you'll need a pair of boys and a pair of
girls for the recorder end) and be prepared to install some jumpers or
move wires in the connectors. The only person who can tell you exactly
what to do is someone who has exactly what you have. He isn't here. <g>

[Mike Rivers]

Laurence Payne wrote:

> This is where you buy a soldering iron and learn a
> very necessary skill. You've just described perfectly why it IS
> necessary for you :-)

Best answer so far.

[Mike Rivers]

ucaudio wrote:
> M-Audio --> Sony
> The general consensus seems to be that I can use standard balanced TRS
> to XLR cables for this (even though the M-Audio can output balances or
> unbalanced levels etc)

Yes. Given that explanation, the output jacks on the M-Audio are wired
so that whether you plug in a TRS plug and go to a balanced input or a
TS plug and go to an unbalanced input, it will work.

> Sony --> M-Audio
> I don't see a termination switch on the machine. Mike said "you can
> use a cable that has the tip wired to Pin 2 and the sleeve wired to
> pins 1 and 3." If I found a cable like this, would that effectively be
> the same as if I were to use a standard XLR to TRS and place a 620 ohm
> shunt resistor between pins 2 and 3 of the XLR outputs of the Sony?

No. The signal coming from the MCI is between pins 2 and 3. Pin 2 will
be wired to the tip and Pin 3 will be wired to the sleeve of just
about any XLR-TRS cable you buy, but the problem is that there's no
sleeve contact on the M-Audio unbalanced input jack. So you need to
connect Pin 3 to the M-Audio ground (sleeve) in order to have signal
from the MCI appear between tip and sleeve (the M-Audio input).

A 620 ohm resistor between pins 2 and 3 would just load down the
output of the recorder. That's the "ternination" that Scott was
talking about, but you probably don't need it.

> the 2 front inputs of the unit accomodate Hi-Z (either XLR or
> 1/4" TRS).

If the 1/4" jacks on the front are really TRS and will accommodate a
line level, then you can use them. But I suspect that they're really
intended for a guitar pickup since you said they're high impedance.

> Here is a pic of the M-Audio unit:

A picture doesn't help. They all look like that. Got a schematic? Or
at least a block diagram?

[Paul Stamler]

"ucaudio" > wrote in message
oups.com...
> Alright sounds good. I'm surprised no standard cables are sold that
> let you run Bal XLR into 1/4" TS in a situation like this. Looks like
> I will have to hire someone to make me some cables since I don't have
> a soldering iron. Might try a website like www.markertek.com.

Actually there are; Radio Shack sells one. But it's pin 3 hot, and you don't
know yet how you want to wire up your cable anyway.

Peace,
Paul

[ucaudio]

Went ahead and ordered these tip to pin 2 Hosa cables.

http://www.hosatech.com/hosa/products/PXF-100.html

Hopefully these will work fine and won't require any modification,
soldering, or the addition of a shunt resistor.

[Scott Dorsey]

ucaudio > wrote:
>Went ahead and ordered these tip to pin 2 Hosa cables.
>
>http://www.hosatech.com/hosa/products/PXF-100.html

Hosa cables do not have a good reputation.

>Hopefully these will work fine and won't require any modification,
>soldering, or the addition of a shunt resistor.

You will still need a shunt resistor in order to match an old-style
transformer output to a new-style high-Z input. You'll get signal
through without the termination resistor, but the transformer will
ring and the top end won't sound right.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[ucaudio]

Yes unfortunately Hosa was the only company I found that specifically
advertised their cable was tip to pin 2. I believe this sony, revision
C, was manufactured in the early 80's. Is there a way to know for sure
if I will need the addition of a shunt resistor? Note, 600 ohms
balanced is printed under the rear xlr output jack allthough the
manual (purchased seperately) mentions 100 ohms balanced output.

[Scott Dorsey]

ucaudio > wrote:
>
>Yes unfortunately Hosa was the only company I found that specifically
>advertised their cable was tip to pin 2.

Everything made today is wired pin 2 hot. But, since it's transformer-
coupled, it doesn't really matter. You can wire the unbalanced line to
pin 3 too and ground pin 2 and it won't matter a bit as long as you don't
care about preserving absolute phase.

>C, was manufactured in the early 80's. Is there a way to know for sure
>if I will need the addition of a shunt resistor? Note, 600 ohms
>balanced is printed under the rear xlr output jack allthough the
>manual (purchased seperately) mentions 100 ohms balanced output.

It has an output transformer. It's possible that it has a good enough
output transformer that you can get away with leaving it unterminated,
but I wouldn't, especially since it will take two minutes with a soldering
iron to do the job.
--scott

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

[Paul Stamler]

"ucaudio" > wrote in message
ups.com...
>
> Yes unfortunately Hosa was the only company I found that specifically
> advertised their cable was tip to pin 2. I believe this sony, revision
> C, was manufactured in the early 80's. Is there a way to know for sure
> if I will need the addition of a shunt resistor? Note, 600 ohms
> balanced is printed under the rear xlr output jack allthough the
> manual (purchased seperately) mentions 100 ohms balanced output.

You still haven't determined the single most important thing: is the output
section transformer-coupled, or not? The early 1980s were a time of
transition, and some companies were beginning to use electronically-balanced
output sections rather than transformer-coupled.

The manual should say. If it doesn't, open up the console and look for
transformers connected to the output jacks. They won't be small.

Really, you need to find out.

Peace,
Paul

[ucaudio]

The manual makes no reference of transformers and there are no
transformer symbols on the block diagrams. I also have looked in the
electronics droor and there are no transformers in the unit. Just
wires going from a plastic plug on the amp card for example, to the
xlr jack.

[Paul Stamler]

"Scott Dorsey" > wrote in message
...
> ucaudio > wrote:
> >
> >Yes unfortunately Hosa was the only company I found that specifically
> >advertised their cable was tip to pin 2.
>
> Everything made today is wired pin 2 hot.

Except XLR > TS cables from Radio Shack. Last time I looked they were pin 3
hot.

Peace,
Paul

[chestek]

ucaudio wrote:

> The manual does say the I/O
> Amplifier Board containes balanced amplifiers for the line inoput and
> line output signals.

Sure sounds like electronicly balanced from this (O/Ps) description...

JChestek

[Scott Dorsey]

chestek > wrote:
>ucaudio wrote:
>
>> The manual does say the I/O
>> Amplifier Board containes balanced amplifiers for the line inoput and
>> line output signals.
>
>Sure sounds like electronicly balanced from this (O/Ps) description...

It does. You sure it's a regular MCI JH-110? Those things had the usual
transformer ins and outs, and the transformers were huge and hard to miss.
They weren't on the boards, though, but inside the housing like on the 440s.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[ucaudio]

It is a Sony JH-110C. I think this is possibly the last revision they
made. Here are some pics of the unit:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200052002113&sspagename=ADME:L:RTQ:US:1


> It does. You sure it's a regular MCI JH-110? Those things had the usual
> transformer ins and outs, and the transformers were huge and hard to miss.
> They weren't on the boards, though, but inside the housing like on the 440s.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

[ucaudio]

Well, I finally got all of my cables and hooked the tape deck up to
the m-audio interface. Got everything working except the interface
1/4" TS input is -10db only and has no attenuation control or
anything, all volume control has to be done at the audio source. So,
when I'm monitoring an incoming signal and trying to hit the tape
hard, I'm clipping the hell out of my interface. I'm trying to figure
out the best way to take care of this without losing audio quality.

You guys think a -20db inline passive pad would work? maybe a -30db
inline pad even... I tried running the tape deck into the 1/4" hi-z
instrument jacks (applying the -20db pad buttons on the front of the
deck) and it pads it down, but when I'm running a hot signal into the
deck and monitoring through the interface it's clipping then too.

[Mike Rivers]

On Feb 10, 10:00 pm, "ucaudio" > wrote:

> Got everything working except the interface
> 1/4" TS input is -10db only and has no attenuation control or
> anything, all volume control has to be done at the audio source. So,
> when I'm monitoring an incoming signal and trying to hit the tape
> hard, I'm clipping the hell out of my interface.

> You guys think a -20db inline passive pad would work?

That would probably work. There's an output level adjustment on the
reorder (a trimpot) and you could bring it down with that. Got the
manual?

[ucaudio]

Ok cool thanks. Yeah I have a photocopied version of the manual off of
Ebay. So if I locate the output trimpot and turn that down is that
basically an attenuator? ... in that it won't really change the tone
or quality of the signal, just lower the decibals? maybe inline pads
are the way to go.


> That would probably work. There's an output level adjustment on the
> reorder (a trimpot) and you could bring it down with that. Got the
> manual?

[Paul Stamler]

"ucaudio" > wrote in message
ups.com...
> Well, I finally got all of my cables and hooked the tape deck up to
> the m-audio interface. Got everything working except the interface
> 1/4" TS input is -10db only and has no attenuation control or
> anything, all volume control has to be done at the audio source. So,
> when I'm monitoring an incoming signal and trying to hit the tape
> hard, I'm clipping the hell out of my interface. I'm trying to figure
> out the best way to take care of this without losing audio quality.
>
> You guys think a -20db inline passive pad would work? maybe a -30db
> inline pad even...

20dB ought to do it. Your tape machine's +4dBu out; let's assume 20dB of
headroom when you happen to be switched to Source on the analog deck, so
that's +24dBu max.

The M-Audio interface that I tested (Delta 66) put a digital signal
of -14dBFS into the computer when the input level was the nominal -10dBV
(-7.8dBu). That means you have 14dB of headroom over -7.8dBu, so the thing
will clip at +6.2dBu. That means your maximum analog tape machine output is
17.8dB too hot. A 20dB pad should do ya; since you're recording 24 bits, a
little extra headroom won't hurt anything, so a 26dB pad will probide a bit
of insurance. Rseries = 10k, Rshunt = 562 ohms. Assuming your interface's
input impedance is 10k, you'll get close enough to 26dB attenuation as makes
no never mind.

Peace,
Paul

[Mike Rivers]

On Feb 11, 12:26 am, "ucaudio" > wrote:
> Ok cool thanks. Yeah I have a photocopied version of the manual off of
> Ebay. So if I locate the output trimpot and turn that down is that
> basically an attenuator? ...

Yes, if you find the right control it only affects the output level.
There are lots of them though, so be sure you're tweaking the right
one. Understand, however, that there's a standard output level for
tape decks - so many volts out for a given fluxivity of tape moving
across the heads. This is one of the adjustments that you make when
you do an electronic alignment on a tape deck. You use a standard
calibration tape (with tones at a known level) to set this. Chances
are the recorder is already set (pretty close anyway) to one of the
standard reference fluxivity levels.

If this is all your own stuff and you're doing it for convenience
there's no reason not to change this adjustment, but if you want to
get the tape deck back to a standard playback level, you'll need a
calibration tape, or at least a secondary standard tape (one you make
on the recorder when it's set up correctly) to reset it.

[Scott Dorsey]

ucaudio > wrote:
>Well, I finally got all of my cables and hooked the tape deck up to
>the m-audio interface. Got everything working except the interface
>1/4" TS input is -10db only and has no attenuation control or
>anything, all volume control has to be done at the audio source. So,
>when I'm monitoring an incoming signal and trying to hit the tape
>hard, I'm clipping the hell out of my interface. I'm trying to figure
>out the best way to take care of this without losing audio quality.

You can recalibrate the machine for a higher tape operating level,
and use the DAW meters instead of the tape machine meters. Or pad
it.

>You guys think a -20db inline passive pad would work? maybe a -30db
>inline pad even... I tried running the tape deck into the 1/4" hi-z
>instrument jacks (applying the -20db pad buttons on the front of the
>deck) and it pads it down, but when I'm running a hot signal into the
>deck and monitoring through the interface it's clipping then too.

Sure. Again, it takes ten minutes to make a pad on the bench. Note
also that you are running the output unterminated and that is probably
increasing your levels a lot too.

Add a 600 ohm shunt resistor, see what the levels are like. If they
aren't in the ballpark, add some series resistance (say, two 4.7k
resistors) on each leg. Make your own pad. It's cheaper than tying
up an adjustable pad.

You ought to have a bag of those Shure adjustable pads in the studio,
but for a permanent install it's more elegant to just add some fixed
resistors in the cable.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[ucaudio]

Thanks for all the input. Just bought some switchable attenuators and
got everything working right... now time to align and calibrate the
machine. First time I've ever done this. Got the manual, a new MRL
test tape, and a lot of info from the net. What I don't have is an
oscilloscope. Going to try to use Cubase and the waves PAZ stuff.
Might try to find a free oscilloscope plugin (I know it's not going to
be as good as the real thing). Anyway thanks again, can't wait to put
this tape deck to use.

[Mike Rivers]

On Feb 11, 3:36 pm, "ucaudio" > wrote:

> What I don't have is an
> oscilloscope. Going to try to use Cubase and the waves PAZ stuff.

Doesn't Cubase have a "phase scope" display? If so, that should work
to indicate proper head alignment. To get in the ballpark, just
monitor one channel and adjust the alignment for maximum output. You
might find several peaks. Make sure you center it on the biggest one.
Then look at both channels and fine tune the head alignment so that
they're in phase when playing the 10 or 15 kHz alignment tone on the
test tape.

[Paul Stamler]

"ucaudio" > wrote in message
oups.com...
> Thanks for all the input. Just bought some switchable attenuators and
> got everything working right... now time to align and calibrate the
> machine. First time I've ever done this. Got the manual, a new MRL
> test tape, and a lot of info from the net. What I don't have is an
> oscilloscope. Going to try to use Cubase and the waves PAZ stuff.
> Might try to find a free oscilloscope plugin (I know it's not going to
> be as good as the real thing). Anyway thanks again, can't wait to put
> this tape deck to use.

An oscilloscope plugin will drive you nuts. An alternative, since your deck
has balanced, transformer-coupled outputs, IIRC: Hook up the attenuators,
then a summing network, so you're looking at the combined outputs. Tweak the
azimuth for peak output on the coarse azimuth signal, then further tweak on
the fine azimuth signal. Note that there are a coupls of false mazima on
either side of the real one, so tune back and forth until you find the
absolute highest level with the two signals summed.

Now get a polarity reversing cable (XLR Female pin 2 goes to Male pin 3 and
vice versa) and insert it into one of the channels. The summed signal will
now cancel. Fine-tweak the azimuth for maximum cancellation.

It's important to know that after you adjust azimuth and then playback EQ
with your alignment tape, you should go back and recheck azimuth. The
playback EQ tweaking changes the phase of the high-frequency signal, and
your azimuth may no longer be exactly right. If necessary, re-tweak the
azimuth, then re-tweak the playback EQ. That should get you right.

When, later, you adjust record head azimuth and then bias & record EQ, the
same applies: you should go back and recheck the azimuth and, if necessary,
re-tweak the record EQ.

Peace,
Paul