Tube Rolling in ART pres

T

Twinnesota

New member
Yeah, I know...lots of people think the ART MP STUDIO and ART TPS II are junk. But alas, I have them. I got 2 each of the MP's for $30 apiece, though...so they are channels that may prove useful for drums at least.

I know they are starved plate pres, and that the tube cannot do everything it is supposed to do because of the voltage. In my endless searching for an upgrade mic pre that would not break my small bank, I ran across a review that said rolling the tubes in the TPS II would make a difference. So I decided to order out some 12AX7's and try it in all of the pres. They are not here yet, but I ordered a a couple of Tung-Sol, Penta Labs, and Sovtek LPS 12AX7's from Doug's Tubes.

I may just wind up thowing the tubes in a drawer and letting the "roll around", LOL, but if it improves the pres a bit I will be happy.

Has anyone else tried this, particularly with the TPS II? I mean REALLY tried it. Please don't tell me that the pres are junk, because I have already heard that ad nauseum. I just have a small home studio...

Any comments or experience you care to share?

Thanks and take care,

T
 
sure, it will make a difference. particularly by subbing tubes with different gain factors, like 12AU7 for example.

ive never subbed tubes in (or even owned) any art tube pres, though i have used the vanilla tube mp a few times, as lots of people seem to own them.

i have subbed tubes in starved-plate distortion boxes, though. i have a tube works 301 rock and a blue tube. using a lower gain tube is especially useful in the 301 pedal, which is pretty over the top for my tastes with the 12AX7 (chinese). the last sub i made was a ge 12AY7, which seems to increase the usable range of the gain control, whereas the stock tube gets either fizzy or brittle at extreme settings. almost amazingly, a "real" mullard ECC83 had the same fizzy sound as the chinese one, and while the voicing was a little different, it wasnt astounding, and i really didnt like it any better. in the blue tube though, different story. the mullard tube is fat and warm in there, but really, the groove tubes (sovtek) that was in there when i bought it is fat and warm as well, at least in the blue tube.

i guess what i am trying to say is that IME the gain factor of the tube seems to make a much more dramatic change in a starved-plate guitar pedal, with tubes of similar gains sounding a lot alike one another. apparently, the circuitry colors the sound more than the actual tube characteristics. i cannot say how this will translate to art preamps, or for that matter, any other starved-plate designs.

but there is one way to find out!

a
 
I thought I already said that...about junk
By golly it was the first sentence in my initial post!!
I guess you are one of those people...
Thanks for the links anyway, but who besides me would change out the op amps for a nominal fee?
T
 
generalchaos316 said:
+1 to pipe's question. Haven't heard of that before and it isn't on Wikipedia so I have to wonder if it is a real term. :D
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First result from Google for "Tube Rolling":

http://64.233.167.104/search?q=cache:bVcPigVP5boJ:www.positive-feedback.com/Issue15/845.htm+%22tube+rolling%22&hl=en&ct=clnk&cd=2&gl=us&client=firefox-a

Heh...I'd never heard of it, either, until now. Apparently it's a fancy way of saying "Tube Swapping". That's what I got from the 4 and 1/2 seconds I spent reading that article, anyway...
 
Maybe "turd polishing" would be a more appropriate phrase. I've never seen anyone swapping the tube in say a UA 610 use the phrase.

Seriously twinnesota, you might try swapping the opamp and signal path caps for a bigger upgrade in sound. A few folks on the Prodigy Pro forum have done this with good results. Even if you're on a budget, these upgrades will cost less than $10-15. If the stock tube is noisy, it will hurt your signal too, even with almost none of the signal routed through it.
 
craigmorris74 said:
Maybe "turd polishing" would be a more appropriate phrase. I've never seen anyone swapping the tube in say a UA 610 use the phrase.
Click to expand...

tell that to your guitarist, heh heh. that he is polishing his turd of an amp by swapping preamp tubes. if youve never experienced it, the difference that another tube of a similar type but different manufacture can make in a hi-fi circuit is not only noticeable, but quite obvious. ditto guitar and bass equipment. why *shouldnt* it make a difference in a high quality preamp? but, as was alluded earlier, starved-plate designs do not use the tube the same way as a traditional circuit. hence the OPs question.

a

btw, no offense implied or intended to anyone.
 
Well, I am a guitarist, and my tube amps use preamp tubes for amplification, so changing them can be very useful. I wasn't denying the changing the preamp tubes in a Groove Tubes Brick to Telefunkens wouldn't be a significant upgrade. But people who upgrade their hi-fi tube amps don't use the corny "tube rolling" phrase. They just swap tubes.

The tubes in this DO NOT amplify the signal and are there to add distortion/noise to the signal. Starved plate tubes could be used to amplify the signal, just not in this design. IMO, replacing the signal path ceramic caps would be a bigger upgrade the tube swap.
 
I never knew I was tube rolling -- guess I do now :D:

I've got two "toob" preamps -- an ART MP Studio one like you're talking about (not to be confused with the full voltage, if input-transformerless ART Digital MPA, which I also have and like a lot) and a Presonus tube-pre. I got an improvement by switching out the 12ax7 in both the Presonus and the MP Studio, because it resulted in less noise. It didn't really change the sound other than that, as far as I could tell. I use the Presonus one for bass DI. My MP Studio still has too much noise, even with the quieter tube. Maybe I should consider that opamp/cap upgrade.

The good part is that the tubes I used in the preamps aren't ones I wanted to use in other places (like guitar amps or the Digital MPA), because I thought they sounded bad -- in the toob preamps, they made no difference other than reducing noise. So... tubes I thought were useless found a use.

Another related adventure you can skip is trying out other 12A*7 tubes in toob units, like the 12AT7 or 12AU7 - makes no difference, as far as I can tell. I have a couple of VOX modeling things (an amp and a dedicated modeler) that have 12AX7s, and I was able to improve their sound with these other models (12AT7 in the amp, and 12AU7 in the modeler), so I was pumped about trying them in the preamps -- no dice, other than a noise reduction in some cases, but that was no better than what I was getting with the 12AX7s.
 
Shoot Twinnesota, didn't want to make you give up. Changing the tube will change the tone of the distortion effect, if that's what you're going for. Just wanted to steer you toward some changes that some pretty smart folks did to make the simple solid state amplification circuit more hi-fi. Don't let a party pooper like me spoil your curiosity.
 
craigmorris74 said:
Well, I am a guitarist, and my tube amps use preamp tubes for amplification, so changing them can be very useful. I wasn't denying the changing the preamp tubes in a Groove Tubes Brick to Telefunkens wouldn't be a significant upgrade. But people who upgrade their hi-fi tube amps don't use the corny "tube rolling" phrase. They just swap tubes.

The tubes in this DO NOT amplify the signal and are there to add distortion/noise to the signal. Starved plate tubes could be used to amplify the signal, just not in this design. IMO, replacing the signal path ceramic caps would be a bigger upgrade the tube swap.
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ok, i dig what you are saying. i did mention in my first reply that i am not familiar with the art circuit. in fact, my total experience with art tube mp was either between my acoustic and a board, or as a go-faster-sound-better mic preamp and DI in the fabulous porta studio daze. none of them were mine, and that isnt likely to change. ahhh porta potties... um... studios... stepping up to vs-880 then 1680 (in "when it was new" dollars :eek:) was simultaneously a home recording epiphany and a lesson in the fundamentals of credit.

a
 
craigmorris74 said:
The tubes in this DO NOT amplify the signal and are there to add distortion/noise to the signal. Starved plate tubes could be used to amplify the signal, just not in this design. IMO, replacing the signal path ceramic caps would be a bigger upgrade the tube swap.
Click to expand...

Are you sure about that? Have you traced the circuit? It's true that some starved-plate tube preamps have a blend control, but the ARTs I've had do not. When you pull the tube, they stop transmitting signal, period.

Now ART has made a lot of flavors of the Tube MP, I have only owned the old Dual MP (two tube MPs in a rack), and now the Digital MPA. The DMPA has a switch to go from full plate to low plate voltage. When you turn it to low (which I would never do), the gain drops, as you would expect. These are not the symptoms of a parallel signal path.

You might look in an old MP mod thread and see comments I made several years ago. I modded the crap out of my old Dual MP. Changing the tubes clearly does change the tone. Swapping the opamps and caps helps too. Although the signal path electro caps are a much bigger factor than the ceramics, which are mostly operating way up in the RF range.

Fortunately, the DMPA comes with good opamps (and the early versions like mine have killer conversion). So a quick tube swap for some vintage Philips JAN and I was off. No, the Tube MP isn't as good as the DMPA. With some good mods (primarily a new power supply), it could get close.

After years of daily use, my gain pots are noisy, and cleaning hasn't helped. I am probably going to swap them out for rotary switches, and just in case replace the caps around them. Other than that . . . no problems, no complaints.
 
In the one I had, I pulled the tube and it still functioned. Put it back in, and it just seemed to make the signal louder like a fuzztone makes a signal hotter, not like a good tube pre functions at all. After that, I got disgusted, as I assumed the signal could be routed through as an effect. I, of course could be completely full of crap with that assumption.
 
craigmorris74 said:
In the one I had, I pulled the tube and it still functioned. Put it back in, and it just seemed to make the signal louder like a fuzztone makes a signal hotter, not like a good tube pre functions at all. After that, I got disgusted, as I assumed the signal could be routed through as an effect. I, of course could be completely full of crap with that assumption.
Click to expand...

Well, as I said ART has made a lot of different models. You can design a tube as a parallel gain path if you so desired. I think the VTB takes that approach. I don't have a philosophical problem with it though. Let's say there was a full-plate, transformer-coupled pre with a parallel solid-state path. I don't know of such a beast, but somebody might think it was a clever feature set. After all, people debate whether to use a solid state or tube pre. Why not both? So it's really just a matter of execution.

For example, if you used your high-plate voltage guitar amp as a mic amp, you might find the distortion not too pleasant for that use. It might still be better than the ART hit hard, because I'm pretty sure that distortion is a result of the second solid-state stage getting clipped. But you wouldn't consider the guitar amp design a hi-fi pre, even though it sounds really good.

One place on ART's site, they claim that the tube adds +40dB of gain. It doesn't seem likely that is the case for all their models, maybe their current models though.

Anyway. You really can't assume anything about the different models and brands without trying them. Bottom line is, it doesn't particularly matter the architecture, if the result sounds good. Now, the Tube MPs don't sound good if you hit them hard. Especially unmodded. But that's true even if you remove the tube, and if required, jump it (with a cap!).
 
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