Swapping tubes in ART gear

Brian · Post by **Brian** » Sat Feb 28, 2009 11:34 am

JWL wrote:Not sure I'd bother trying to raise plate voltage in the ART TubeMP circuit, since it's a starved plate design.

What would it do?

themagicmanmdt · Post by **themagicmanmdt** » Sat Feb 28, 2009 4:33 pm

i was told by a circuit guru that your 12A_7 tube varieties can work on both full and lowered plate voltages. if anything, it's when the voltage it pushed next to the saturation point that things get unlinear.

so, the tube MP is mostly still an IC based preamp, with one stage being treated 'gently' with a linear, non-'hot- tube.

you don't push the tube when you drive the preamp - the output clip sounds and is clearly an IC distortion.

so, with this experience, the tube rolling will affect sonic character - not the distortion or drive of the MP - and other parts of the unit are definitely more to blame for the colored sound (which totally has it's unique place in my studio). the voltage on the plate is not the culprit - it's all the other chips you go through, the quality of the caps in the signal path, etc etc -

Brian · Post by **Brian** » Sat Feb 28, 2009 5:46 pm

themagicmanmdt wrote:i was told by a circuit guru that your 12A_7 tube varieties can work on both full and lowered plate voltages. if anything, it's when the voltage it pushed next to the saturation point that things get unlinear.

so, the tube MP is mostly still an IC based preamp, with one stage being treated 'gently' with a linear, non-'hot- tube.

you don't push the tube when you drive the preamp - the output clip sounds and is clearly an IC distortion.

so, with this experience, the tube rolling will affect sonic character - not the distortion or drive of the MP - and other parts of the unit are definitely more to blame for the colored sound (which totally has it's unique place in my studio). the voltage on the plate is not the culprit - it's all the other chips you go through, the quality of the caps in the signal path, etc etc -

That's good to know, but, how do they accomplish "treating" the sound, by mixing in a little?
How does one of those units sound, color-wise?
Maybe I'll get one and tinker with the ting meself.

junkyardtodd · Post by **junkyardtodd** » Mon Mar 02, 2009 1:07 pm

I've got a Tube Pac that sounds pretty okay for general recording stuff, but works really great if I want to add some fuzzy weirdness, like to re-amp a vocal or guitar or drum track.

psinglet · Post by **psinglet** » Tue Mar 03, 2009 10:27 am

Someone gave me a pair of Telefunken 12AX7 tubes, and on a whim I put them into a pair of Tube MPs I had lying around to see what it would do. I tried them on a live stereo recording for a choir using AT 4033s in an XY pattern. I have to say, it's a very natural sound. It's my go-to "straight to a CD recorder" setup now. The tubes, however, are probably worth more than the preamps.

kinger · Post by **kinger** » Wed Mar 04, 2009 3:53 am

I just discovered an old T.V. repair shop in town here with a bunch of N.O.S. tubes in stock so I'm going to pick up some G.E. 12AT6s tomorrow and give them a whirl. If I were evil, I'd buy everything he has and re-sell them on evilBay as he's letting them go cheap. Oh wait, I am sort of evil...

inverseroom · Post by **inverseroom** » Wed Mar 04, 2009 4:52 am

I put NOS JAN Phillips tubes in my Pro VLA and there was no difference whatsoever.

mixedupsteve · Post by **mixedupsteve** » Wed Mar 04, 2009 7:00 am

inverseroom wrote:I put NOS JAN Phillips tubes in my Pro VLA and there was no difference whatsoever.

I think it's just a tube buffer in the circuit. How do you like the VLA?

mixedupsteve · Post by **mixedupsteve** » Wed Mar 04, 2009 7:04 am

kinger wrote:I just discovered an old T.V. repair shop in town here with a bunch of N.O.S. tubes in stock so I'm going to pick up some G.E. 12AT6s tomorrow and give them a whirl. If I were evil, I'd buy everything he has and re-sell them on evilBay as he's letting them go cheap. Oh wait, I am sort of evil...

Only take the audio tubes. Most of the TV type tubes are dime a dozen. I literally picked up a box of tubes off the street. Most were worthless. I've got a bunch of Metal 6v6s though!

inverseroom · Post by **inverseroom** » Wed Mar 04, 2009 8:48 am

mixedupsteve wrote:
inverseroom wrote:I put NOS JAN Phillips tubes in my Pro VLA and there was no difference whatsoever.
I think it's just a tube buffer in the circuit. How do you like the VLA?

It's solid! It's now the only hardware comp I use. vox and acoustic always go through it...good, clean sound.

trodden · Post by **trodden** » Wed Mar 04, 2009 1:53 pm

inverseroom wrote:I put NOS JAN Phillips tubes in my Pro VLA and there was no difference whatsoever.

there are a difference between the JAN and the mullards I have.. both are good sounding, but different.

BENDYmusic · Post by **BENDYmusic** » Wed Mar 04, 2009 6:21 pm

Currently I have an ElectroHarmonix and an Ei Elite tube in my ProMPA. Sound is much improved but I still never use this preamp as I have much more interesting options these days.

CDSoundMaster · Post by **CDSoundMaster** » Wed Mar 04, 2009 10:33 pm

The MPA Gold has a high voltage setting for normal operation.

ysyrtypy wrote:I did that with an MPA Gold and I'm not sure I could tell the difference. I only did it cos I had extra tubes laying around. The circuit, being starved plate, isn't really putting much heavy lifting onto the tube anyhow.

Brian · Post by **Brian** » Thu Mar 05, 2009 5:40 am

CDSoundMaster wrote:The MPA Gold has a high voltage setting for normal operation.

ysyrtypy wrote:I did that with an MPA Gold and I'm not sure I could tell the difference. I only did it cos I had extra tubes laying around. The circuit, being starved plate, isn't really putting much heavy lifting onto the tube anyhow.

WHAT??
IS THIS TRUE??
Ifso, I want one of THOSE.

kinger · Post by **kinger** » Thu Mar 05, 2009 12:38 pm

This is true; you can switch between starved plate and 300V.

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Swapping tubes in ART gear

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