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Post by Jason on Mar 9, 2015 21:54:05 GMT -6
I have two mono preamps I use to record stereo guitar. The preamps aren't a matched pair, and there's a noticeable difference in input gain between units. In addition to just using my ears, is there a more exact procedure to match gain between these preamps (i.e., using a signal generator perhaps)?
Sorry if it's a noob question, but I appreciate any guidance you all may lend.
Thanks,
Jason
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Deleted
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Post by Deleted on Mar 9, 2015 22:27:51 GMT -6
You could level in one of both to the signal you wish to record, then feed a test signal from a signal generator thru both preamps and match the level of the second according to your DAW's level meter readout of the first one. This would ensure same gain on both pre's.
Everything beyond that depends on the architecture of the pres. If they use rotary switches for gain settings, you should be able to exact level match them in hardware with addition of resistors, there is also a chance that you can calibrate gain elements inside the units....
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Post by Jason on Mar 9, 2015 23:36:48 GMT -6
Can I use any frequency signal, say 400 Hz? I'm referring to my pair of tonebeasts, if this helps...the input gain set on the rotary doesn't quite match up with the same setting on the other one...I've been matching by ear, and it's close enough for government work...was just curious if I could approach it in a more systematic fashion. Thanks, Jason You could level in one of both to the signal you wish to record, then feed a test signal from a signal generator thru both preamps and match the level of the second according to your DAW's level meter readout of the first one. This would ensure same gain on both pre's. Everything beyond that depends on the architecture of the pres. If they use rotary switches for gain settings, you should be able to exact level match them in hardware with addition of resistors, there is also a chance that you can calibrate gain elements inside the units.... |
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Deleted
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Post by Deleted on Mar 9, 2015 23:56:20 GMT -6
Yes, use whatever you might have at hand, as long as both units are not sonically off of each other, means having different frequency response, it's ok and alot more precise than setting by ear.
Well, i don't know the Tone Beasts inside, maybe one of the other owners around here knows, if there is a calibration option inside.
Otherwise - i would simply inquire at Warm Audio, send them a mail asking how you could calibrate/level match the TB12 (this is, what we are talking about, right?).
Could be there is a precision pot inside for such tasks. At least this would come handy for stereo matching. AFAIK it's a kind of 312 style amp with switchable exchangable discrete opamps, probably it is just possible to calibrate with a small screwdriver.
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Post by svart on Mar 10, 2015 10:00:11 GMT -6
As @smallbutfine says, just use any old signal with a steady output. Use a Y cable and just match the outputs on your DAW meters.
I would probably go a step further and see if they match at all gain settings. if not, you might have a bum/out of tolerance gain pot.
If they do match, they at least you know how to offset them from that point on.
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Post by Jason on Mar 10, 2015 10:12:51 GMT -6
Thanks, guys! They're only off a few clicks from one another, quantifying the offset for future reference is all I'm shooting for, although I will certainly experiment to determine whether the offset is true at all gain settings.
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ericn
Temp
Balance Engineer
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Post by ericn on Mar 10, 2015 10:53:38 GMT -6
This is one of the situations where I love my IPhone
Audio tools gives me all kinds of generators and metering! Best investment ever!
If I'm trying to get a good match of unmatched sources I have been known to use pink noise and the FFT to get an idea of the freq response to get an idea of more than just the level !
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Post by category5 on Mar 10, 2015 12:08:56 GMT -6
Feed a common signal to both, invert phase on one, and adjust for maximum cancellation.
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