Tubefex Tube Question (Mike Brown or anyone?)

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Bobby Lee
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Tubefex Tube Question (Mike Brown or anyone?)

Post by Bobby Lee »

The Peavey Tubefex uses 2 12AX7 tubes. It has 4 tube modes: Clean, Crunch and two awful sounding ones.

My question: how are the tubes used to get these sounds? It almost seems like the output of each of the 4 stages is fed into the next one. If so, which tube is handling the Clean & Crunch modes?

I notice that I don't get any sound at all if I remove one of the tubes. Image Second question: Is there any way to disable the two awful sounding modes? Sometimes I switch them in by accident on the front panel and they make really loud, ugly noises.

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Post by Bobby Lee »

I realize that "awful sounding" is a subjective term. I'm sure there are people out there who love those sounds. They just don't work well with the steel guitar, in my opinion.
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Jack Stoner
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Post by Jack Stoner »

b0b, I don't use them on my TT Fex, except for one distortion program. By having a program with "crunch" mode programmed in it, I avoid switching between the different preamp modes with the separate switch. All my other programs only use the clean mode.

I've tried the other modes with my Telecaster and it even sounds "bad" with it.
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Post by Bobby Lee »

Right. I've actually found "Crunch" to be pretty useful for rock. The problem is that sometimes I hit the tube mode switch by accident. Also, to get from Crunch to Clean you have to go through the other two, which can squeal depending on your other settings.

But my real question is: Which tube does what? I want to put my quietest tube in the Clean part. Otherwise I'd be wasting it.
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Jack Stoner
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Post by Jack Stoner »

b0b, what might be easier than going through the modes is to just hit the program up or down and then go back to your original program. That will reset the mode without going through the series of modes to get back to the clean.

I can't help you with the tubes since I have the transtube model.
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Tim Harr
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Post by Tim Harr »

Hello Tubefex users,


I have two questions.....

Question 1.
When I scroll through my patches that include the "TB" tube preamp, I hear an AWFUL "cycling" sound of the electronic pots resetting.

It is almost like a "chuuh, chuuh, chuuh,....etc " type sound.


Does anyone else hear that?


Question 2.
When using a patch that includes the "TB" preamp, do you ever find that when you go to it - it seems like that the gain is not as strong...THEN you go one up then back and it returns to the expected volume....


I may need to send it to Mike and the folks at PV in Miss. If that is the case, fine at leat I will get it serviced correctly.
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Jack Stoner
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Post by Jack Stoner »

Tim, I have a Transtube Fex, but other than it's solid state rather than Tube everything else is the same.

I don't hear any noises, other than possibly one small click, going from a program without the TB to one with, it's instantaneous. However, I rarely use anything but programs with the TB (analog) preamp. And except for one distortion program everything I use is with the Clean mode (which is where the click comes in).

I don't have any problem with the gain changing on the programs either.

The front panel gain/EQ controls are MIDI controls and I'm not sure exactly how they work but it sounds like there is some kind of problem with them - possibly causing both problems that you describe.

One thing you can try, if you have a cache card with all your programs backed up, is to do a "factory reset" and see what that does for it. The "factory reset" seems to cure a lot of flakey problems in these units. This is a lot easier and cheaper than sending it in for service and if it works great, if not then you haven't really lost anything as the next step is to send it in for repair.

However, before you send it in (if it gets to that point) call Mike Brown and discuss it with him as he may have something else for you to try. Mike is in and out of his office and sometimes hard to catch but keep trying. His number is 1-877-732-8391.


Bill Crook
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Post by Bill Crook »

b0b....

The way the unit is designed, you canot remove a tube and get past the stuff you don't like. The way the tubes are designed, It is really two (2) triode tubes in one (1) glass envelope. I thing the signal is cascaded thru the tubes to get the "crunch" sound,so really , it's just a very over driven signal. To remove a tube only kills the signal path.

Mike Brown really would be the person to ask about this, as he is "Mr. Peavey" (A most deserved compliment is indicated here.)

I know that the "crunch" effect can be done by using stacked diodes, but it's very much different from the sound of an over-driven tube unit.

Mr. Jack Stoner has the right (and best) idea. just program around it.

My Profex II has the same problem when I rotate thru the high "B" numbers. I guess, sometimes I forget that 6 string guitar players use the Profex II also and they WANT that distorted sound.
<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Bill Crook on 27 June 2000 at 06:38 AM.]</p></FONT>
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Bobby Lee
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Post by Bobby Lee »

What annoys me most about those two super distorted modes isn't the distortion - it's the gain increase. The preamp is much louder on "Ultra" than it is on "Clean" or "Crunch".

And yes, I understand that each tube is two triode amplifiers. My question is, which triode serves what purpose? I suspect that two of the four triodes are irrelevant if you only use "Clean" and "Crunch". Which two?

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Post by Bobby Lee »

The distortion from stacked diodes isn't very musical, in my opinion. I get better tones from my lawnmower. Image I like controlled tube distortion.
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Post by Jerry Wright »

If I am not mistaken bOb you can edit the mode you want in your pre-set.
For instance-take the Crunch out and add Clean in.You can Edit everything in a Pre-set to your likings.
My TF has a bad problem right now and being sent to Mike Brown for repairs.

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Mike Brown
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Post by Mike Brown »

Hello everyone,
The signal is passed through the two 12AX7 tubes in the Tubefex for all of the channel modes. In other words, this gives all channels tube voicing characteristics. Then, the channels are reconfigured in the DSP. Depending on the gain structures and other effects programmed into the chain, there "could be" some presets that have higher gain that could be accidently selected. To solve this accidental selection, I recommend that you remap them in the order of use, then perhaps program two clean presets(1 prior and 1 after) to avoid selecting a preset that doesn't work well for steel. At least a clean preset won't be as obnoxius if accidently selected. Jack Stoner seems to know our products well and provides good suggestion frequently.

As far as the programmable pot noise, our service department can take care of the "resetting" noise and at the same time we will update the unit to the latest software. For the difference in gain when selecting a "TB" preset from a non "TB" in preset, I suggest that you check the internal battery for leakage and replace if necessary.

Jerry Wright is correct in saying that you can edit a preset to your liking and save it in the "A" bank. None of the "distortion" modes have to be in the chain, they can all be programmed in the clean mode. This might help also. Hope that this helps.

I can be reached toll free at 1-877-732-8391.
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Post by Bobby Lee »

Mike, in what order does the signal pass through the tubes? Does it go through 1a then 1b then 2a then 2b? I have two different tubes, and it's hard to know which to put in which socket.
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Post by Mike Brown »

The signal goes through V1A, then V2A, then V1B and then V2B. Hope this helps.
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Post by Bobby Lee »

Thank you very much, Mike. Is "V1" the tube on the left (when viewed from the front)?