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what noise / matching performance would you typically expect from a tube stereo comp
Old 13th November 2009
  #1
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what noise / matching performance would you typically expect from a tube stereo comp

Hallo,

I am currently testing a stereo vari tube compressor (brand doesn't matter, its well above cheap stuff). Wanted to use it on sources and the mix buss. Maybe I am spoiled by plugins, but

- one channel has 10 dB higher noise floor, in a typical situation -76 dBFS (when digitized afterwards with high quality converter) compared to -86 dBFS.

- the same channel has no perfect hum islation

- when the compression in link mode reads 7 dB, there is already a difference of 0.8 dB between channels (440 Hz tone applied), gains calibrated for no compression case (low level input). Of course this is an extreme situation, which should not appear so often on the mix buss in practice, but the device could be used for effect compression.


I don't know what I have to expect from such a device. Do you usually measure your gear or you just don't care? heh So in total I am already able to hear the noise on one channel at a level, which is loud for pop music, but would be not so loud for classic music.

Would be good to know, whether my expectations are simply too high or not.

regards
Old 13th November 2009
  #2
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MASSIVE Master's Avatar
 

Verified Member
I'd submit that "perfect" almost never happens... That said - It's rarely a real issue with quality gear. THAT said, I do whatever I can to avoid tubes most of the time and only have a limited amount of tube gear in 'regular' use here.**

THAT said, yes - Something doesn't sound right with the unit you have.

The 7dB of GR thing is sort of out the window - I'd be much more interested with the link at 1 or 2dB - Maybe 3dB. And of course, making sure the tubes are good (swapping them to see if the problem swaps also) and warmed up well before taking any such measurements, etc., etc., blah, blah...


** I'd hope it's not necessary, but somehow I feel compelled to note that I'm in no way "against" tube gear... I've had plenty, I still have my (Manley) Variable Mu, I hope to go riding with Eve Anna some time if I ever get out that way, I think well-designed tube gear (such as the Manley, Tube Tech, etc. stuff) is wonderful to have - I just prefer to use solid-state gear when I can. Less heat, less goofy maintenance issues (like the one above), etc., etc.
Old 16th November 2009
  #3
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Quote:
Originally Posted by MASSIVE Master View Post
The 7dB of GR thing is sort of out the window - I'd be much more interested with the link at 1 or 2dB - Maybe 3dB.
I measured something like 0.3-0.4 dB.
Old 16th November 2009
  #4
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William Bowden's Avatar
 

Verified Member
2 Reviews written
I'd try swapping tubes one at a time between channels to see if the fault transposes. It's almost always a noisy tube in one channel with results like that...

If there are separate input and output gain controls for each channel it may complicate things further if the unit is also out of cal. If swapping the tubes doesn't work I'd see if you can find a cal procedure for the unit.

My Tubetech cl1a's are around -89 I think, or lower - I forget. I do look at the noise floor of the chain each time I name the files in Sequoia's record dialogue box, but primarily I'm interested in symmetry between channel noise, a tube going bad (low level bumps or pops) or the quality of erasure on my ampex (if I use it).

I like tube gear myself, but would very rarely have three tube units in (and around) the chain, usually two or one, my Massive Passive has the worst noise specs (-68ish)- it's symmetrical but I think over Xmas I'll re-tube the old dear.

The King
Old 16th November 2009
  #5
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thanks for sharing your experience with tubes in general. I could actually contact the company, since this is a new unit (and I have 30 days money-back). Their specs say 90 dB SNR. The case is a bit complicated since various operating points give different SNRs and also different matching accuracy.
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