Hi,
I have a Soundcraft 600 analog console (+4dBu operation level) and a TASCAM 22-2 tape deck (-10dBV operation level) that I've been bussing stereo drums to while tracking, as well as mastering whole stereo mixes to as final product (because why not see what all the analog fuss is about?).
The signal from the Soundcraft is of course seen as very hot coming into the TASCAM and some attenuation has to be done to avoid drastic distortion of the signal to tape (a bit too much analog fuss eh?).
The question is, if one wanted to track or master to tape and maintain as much fidelity of the original signal as possible (maintain the most transient information, lose the least amount of frequencies, least distortion, etc), where is it best to attenuate the signal: at the console output VCA faders? Or patch in an attenuator of some description? Or use as transparent a limiter as possible? Are there solutions I'm missing?
As I write this I realize this might not be such a straightforward answer...
Thanks for any help!
Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
I'm going to attempt a straightforward answer since I wouldn't overthink it. I'd use a passive attenuator at the input of the tape deck and a simple amp at the output, perhaps something like a Samson S-Convert box (there may be others).
It is also possible that the input level controls on the Tascam are entirely sufficient instead of a pad, but that depends on the design of the input circuitry.
If you are really worried about retaining fidelity (it's an old tape machine we're talking about here!) then higher quality pre-amps for the return signal are available.
It is also possible that the input level controls on the Tascam are entirely sufficient instead of a pad, but that depends on the design of the input circuitry.
If you are really worried about retaining fidelity (it's an old tape machine we're talking about here!) then higher quality pre-amps for the return signal are available.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
I use an ART Clean Box, it has level controls, and the quality is excellent.
"I will not say: do not weep; for not all tears are an evil" Gandalf - J.R.R. Tolkien.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Hugh has mentioned the Art boxes as being very good but they do contain transformers and are an added cost.
I would also suggest passive attenuators at the tape machine end, with no more than 2mtrs of exit cable to preserve HF. You could use a simple fixed resistor network but you also have the opportunity to better 'calibrate' the setup by using a pair of 10k log potentiometers.
The desk has LED meters and the recorder has VUs so you could use the pots to get the two meter systems to tally, e.g. "+4dBu out of desk = 0VU" on tape machine. The exact relationship will depend on other factors such as the optimum level for a particular tape type and what sort of 'attitude' you want to push it for. The pots will also allow for the trimming of any channel sensitivity offset.
Of course, you will need to have the basic soldering skills to build such a box but, if you are going to be messing with old analogue kit you better develop some PDQ if you don't already have them. Such a box is really 'beer into water' to build!
Dave.
I would also suggest passive attenuators at the tape machine end, with no more than 2mtrs of exit cable to preserve HF. You could use a simple fixed resistor network but you also have the opportunity to better 'calibrate' the setup by using a pair of 10k log potentiometers.
The desk has LED meters and the recorder has VUs so you could use the pots to get the two meter systems to tally, e.g. "+4dBu out of desk = 0VU" on tape machine. The exact relationship will depend on other factors such as the optimum level for a particular tape type and what sort of 'attitude' you want to push it for. The pots will also allow for the trimming of any channel sensitivity offset.
Of course, you will need to have the basic soldering skills to build such a box but, if you are going to be messing with old analogue kit you better develop some PDQ if you don't already have them. Such a box is really 'beer into water' to build!
Dave.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Skimming through the 600 manual, it states the operating levels for the tape interface can be switched between +4dBu and -10dBV (Tascam level), though it may depend on what modules are fitted to you particular mixer.
It's a scanned manual, so non searchable, but look at section 3.02 (part 1-4 from the Soundcraft site's manual) where it talks about setting the interface module levels.
https://www.soundcraft.com/en/products/series-600
It's a scanned manual, so non searchable, but look at section 3.02 (part 1-4 from the Soundcraft site's manual) where it talks about setting the interface module levels.
https://www.soundcraft.com/en/products/series-600
Reliably fallible.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Wonks, I have only found a part service manual so far but the signal block diagram shows the line input as going directly to the 50K line pot. Therefore the recorder has 'infinite' line input headroom and there is no need for any attenuation AFAICS?
So the chap should be able to back off the controls to get the mixer running at an optimum level but keep the recorder happy. The only possible downside is that the line pots might be at a 'sensitive' point in their rotation making it difficult to set and keep a specific level.
Dave.
So the chap should be able to back off the controls to get the mixer running at an optimum level but keep the recorder happy. The only possible downside is that the line pots might be at a 'sensitive' point in their rotation making it difficult to set and keep a specific level.
Dave.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
The user manual has all the circuit schematics in the last two parts as well as the block diagrams. The trouble is there are so many different slot-in module options available for those mixers that we don't know exactly what modules the the OP has, where he's feeding the tape and where the tape returns are going.
Also the OP may not feel confident enough to remove modules and mess about with switches and jumpers, but it could all be done within the mixer if they want to.
Also the OP may not feel confident enough to remove modules and mess about with switches and jumpers, but it could all be done within the mixer if they want to.
Reliably fallible.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
I think Dave is talking about the Tascam recorder's schematics rather than the console.
I agree that it should be possible to turn down the recorder input level which is itself an attenuator. The only issue there is whether the required setting is sufficiently controllable.
Wonks is right in that some 600 consoles have switchable +4/-10 settings on group outs and tape returns (and some of the master section I/O) which might help.
If not, by far the easiest solution would be to invest in an ART Cleanbox Pro:
https://artproaudio.com/product/cleanbo ... converter/
This is an active (powered via a wall-wart) two-channel bidirectional converter that takes a stereo +4dBu balanced input and converts it to a stereo-10dBV unbalanced output, and vice versa.
It has no transformers. Dave is probably confused with the similar sounding ART Cleanbox II which is a passive line isolator.
Other +4/-10 converters are available, but the ART stuff is good quality and good value for money.
The Cleanbox Pro is about £85.
I agree that it should be possible to turn down the recorder input level which is itself an attenuator. The only issue there is whether the required setting is sufficiently controllable.
Wonks is right in that some 600 consoles have switchable +4/-10 settings on group outs and tape returns (and some of the master section I/O) which might help.
If not, by far the easiest solution would be to invest in an ART Cleanbox Pro:
https://artproaudio.com/product/cleanbo ... converter/
This is an active (powered via a wall-wart) two-channel bidirectional converter that takes a stereo +4dBu balanced input and converts it to a stereo-10dBV unbalanced output, and vice versa.
It has no transformers. Dave is probably confused with the similar sounding ART Cleanbox II which is a passive line isolator.
Other +4/-10 converters are available, but the ART stuff is good quality and good value for money.
The Cleanbox Pro is about £85.
-
- Hugh Robjohns
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In my world, things get less strange when I read the manual...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Not confused Hugh, Arpy didn't specify so I had to guess.
Yes, I was talking about the line pots on the recorder but it would be better practice to leave them set at some reference mark and use that Art box for 'fine tuning'. (the input controls on my Teac have '0' at 1 o'clock which, IIRC gives 0VU for neg 10dBV line in)
Dave.
Yes, I was talking about the line pots on the recorder but it would be better practice to leave them set at some reference mark and use that Art box for 'fine tuning'. (the input controls on my Teac have '0' at 1 o'clock which, IIRC gives 0VU for neg 10dBV line in)
Dave.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Thank you all so much for the valuable information, Sonics, Wonks, Dave, Arpangel, and Hugh.
I have previously gone through all the console modules and made sure that all jumpers are set for +4dBu baseline in/out operation, as I use mainly all analog outboard EQs, compressors, reverbs and other devices that are also calibrated for +4dBu, so I don't want to adjust the console down to -10dBV for that reason I suppose.
The TASCAM 22-2 does indeed have adjustable input potentiometers, though the manual states essentially to keep them at "seven on the dial" when calibrating, so I reckon that's the optimum performance zone for the pot.
All that said, I like the idea of building a passive attenuator box, or purchasing the active Art Cleanbox Pro, and having that in front of the tape machine input or on the patch bay.
Thank you for all your input!
I have previously gone through all the console modules and made sure that all jumpers are set for +4dBu baseline in/out operation, as I use mainly all analog outboard EQs, compressors, reverbs and other devices that are also calibrated for +4dBu, so I don't want to adjust the console down to -10dBV for that reason I suppose.
The TASCAM 22-2 does indeed have adjustable input potentiometers, though the manual states essentially to keep them at "seven on the dial" when calibrating, so I reckon that's the optimum performance zone for the pot.
All that said, I like the idea of building a passive attenuator box, or purchasing the active Art Cleanbox Pro, and having that in front of the tape machine input or on the patch bay.
Thank you for all your input!
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
cashhewn wrote: ↑Tue Feb 28, 2023 3:52 am Thank you all so much for the valuable information, Sonics, Wonks, Dave, Arpangel, and Hugh.
I have previously gone through all the console modules and made sure that all jumpers are set for +4dBu baseline in/out operation, as I use mainly all analog outboard EQs, compressors, reverbs and other devices that are also calibrated for +4dBu, so I don't want to adjust the console down to -10dBV for that reason I suppose.
The TASCAM 22-2 does indeed have adjustable input potentiometers, though the manual states essentially to keep them at "seven on the dial" when calibrating, so I reckon that's the optimum performance zone for the pot.
All that said, I like the idea of building a passive attenuator box, or purchasing the active Art Cleanbox Pro, and having that in front of the tape machine input or on the patch bay.
Thank you for all your input!
Aha! So Tascam on this machine cite "seven" as the input reference setting?
This is a prime example of the crazy mixed up world of audio level standards. No doubt some bod in the design dept' fixed upon 7 as some sort of nod to the dBu reference of 0.775 V when in fact most 'semi-pro' tape machine conform to the 0dB= 1V regime*. The 7 mark on that recorder is at about 2 o'clock. My Teac, as I said is 1 o'clock for '0'.
Yes, makes sense to keep to the mnfctr's suggested setting and you could save yourself a bit of hassle and build a simple fixed attenuator since it would be simple to set any offset needed with the dual concentric knobs.
I would put such an attenuator close to the machine's inputs and 'forget' about it. As you seem to be running +4dBu everywhere else, incorporating it in a patch bay could lead to problems.
*Also used almost universally in the guitar electronics world. Rational people you see!
Dave.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Or you could simply turn the mixer’s output level down.
If it was me, I’d be setting the jumpers on the interface modules to and from the tape deck to -10dBV unless they were also feeding/being fed more important +4dBu signals. The rest of the mixer can stay at +4dBu.
If it was me, I’d be setting the jumpers on the interface modules to and from the tape deck to -10dBV unless they were also feeding/being fed more important +4dBu signals. The rest of the mixer can stay at +4dBu.
Reliably fallible.
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
If it was me, I'd use the Cleanbox Pro (or similar) to convert the consumer tape recorder to professional connectivity standards. It's the neatest, simplest, and most practically convenient solution.
The '7 on the dial' thing has nothing at all to do with 0.775V rms.
The machine's standard operating level is -10dBV (0.316Vrms). 0.775V doesn't come into it.
The standard input control level setting is 7 (out of 10), providing room to turn the level up for quiet sources, and down for loud ones. At a setting of 7, a -10dBV signal will register 0VU on the meters...
The historic and technical reasons for the standard long-established operating levels we have (-10dBV, 0dBu, +4dBu, -18dBFS, -20dBFS) are all well known and understood, and don't cause anyone properly trained in audio any trouble at all..... There is no 1V standard signal level in domestic or pro audio.
The '7 on the dial' thing has nothing at all to do with 0.775V rms.
The machine's standard operating level is -10dBV (0.316Vrms). 0.775V doesn't come into it.
The standard input control level setting is 7 (out of 10), providing room to turn the level up for quiet sources, and down for loud ones. At a setting of 7, a -10dBV signal will register 0VU on the meters...
The historic and technical reasons for the standard long-established operating levels we have (-10dBV, 0dBu, +4dBu, -18dBFS, -20dBFS) are all well known and understood, and don't cause anyone properly trained in audio any trouble at all..... There is no 1V standard signal level in domestic or pro audio.
-
- Hugh Robjohns
Moderator -
Posts: 43685 Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Contact:
Technical Editor, Sound On Sound...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
Re: Where to attenuate +4dBu console signal to -10dBv tape deck to maintain fidelity?
Hugh Robjohns wrote: ↑Tue Feb 28, 2023 10:35 am If it was me, I'd use the Cleanbox Pro (or similar) to convert the consumer tape recorder to professional connectivity standards. It's the neatest, simplest, and most practically convenient solution.
The '7 on the dial' thing has nothing at all to do with 0.775V rms.
The machine's standard operating level is -10dBV (0.316Vrms). 0.775V doesn't come into it.
The standard input control level setting is 7 (out of 10), providing room to turn the level up for quiet sources, and down for loud ones. At a setting of 7, a -10dBV signal will register 0VU on the meters...
Hmm, I wonder why then they didn't go for '0' as on my machine?
Dave.