How to make the Tube Driver sound... good?

[Phorhas]

Hi
I there a way to make the TubeWorks Tube driver sound, well, good? it's horrible... I thought it's supposed to be this legendary tube pedal... to me it's just weak, gritty, fizzy and characterless...

Has anyone tried (and succedded) making it better?

[Ansil]

personally i would take c six and turn it into at least a .1uf personally i like .22uf

try the marshal guvnor tone stack it has more bottom to me i use it always..

[Phorhas]

How about a mesa tone stack... like the Blue Angle's or Subway Blues'?

witll it alone improve sound? maybe a real tube (not that crapy looking Ruby) is in order.

Are the red-brown film caps better than reenies' tonaly?

well, I did replace the LT072 OA with an NE5532 (thay have a socket... how nice of them) and it did improve sound.

oh well, I guess I just have alot of experiments to do

[cd]

Actually that Ruby is probably pretty good.  They made (or rebranded) some of the best modern production tubes ever (1990+).  If I could ifnd some of their silver specials for a good price (they're around $30 a pop these days) I'd snap them up.

Anyway, when I had a Tube Driver I found it hopeless.  The tubes are  just run at too low a voltage to get any kind of "real" tube sound out of them.  The best mod (to my ears) was to put some clipping diodes to ground (like a Rat) just before the tube stages, and to change the tube stages into a cathode follower (ala Marshall) to drive the tone stack.  Kind of defeats the purpose of the tube but it sounded way better.

[Johan]

my own little pet-theory on starved tubes is that they are usualy driven much harder and too much into cutoff, clipping hard instead of smooth overdrive compared to what they would be with high voltages, and thats why it doesnt sound right. Simply trying to get more gain out of fewer stages ( see R.G's tube-f.a.q.)...try a tube with less gain, like 12AT7 or maby even 12AU7 and see if things gets better...


Johan

[Ben N]

I tried substituting a 12au7, and it sounded even worse.  BTW, my TD is the 3-knob one, which I'm told is the worst-of-breed.
Ben

[Doug H]

All starved-plate tube drivers are not created equal.

The BKButler circuit sounds pretty nice. You may get some tips from this:

http://amps.zugster.net/articles/tube-pedals/index.html

I developed a variation of this using pentodes a few yrs ago and I love it. It is definiitely a "holy grail" tone for me. I will try to get my schem back up ASAP and do a sound clip.

Doug

[Phorhas]

That sounds interesting

How about pumping up the voltage? having the OA run at around +18V and the Tubes at around +36V ?

[Doug H]

That sounds interesting

How about pumping up the voltage? having the OA run at around +18V and the Tubes at around +36V ?

You can certainly do that. I don't think it will make that much difference. IMO, the idea that "tubes have to be run at high voltage to sound good" is a lot of mythology. From what I've seen of the myriad "starved-plate" circuits, I suspect that some of them are just poorly designed. Some don't appear to really be designed to run at low voltages at all.

IMO, one of the things the BK Butler circuit does really right is set up the tube stages to run low gain and let the op amp do the driving. When I had this on the breadboard I experimented with high-gain tube stages and it sounded horrible. With such a low voltage you end up with no headroom, no dynamics, and a real thin and buzzy clipping sound. Not good...  When I see schems with large grid-shunt resistors, low voltage (down to 9v) and hear people complain about this sound, I suspect the problem is poor design more than anything else.

With the low-gain tube stages driven by the op amp, you get a smooth clipping tone with a lot of dynamics and decent headroom. I think the 12ax7 circuit sounds alright, but I like it with the pentodes a lot better. You get tighter and punchier bass, clearer highs, and due to the screen circuit, a lot of compression that gives the pedal this incredible "feel factor" that just makes it a lot of fun to play with.

BTW- I put my pentode driver schematic back up here:

http://home.cfl.rr.com/dbhammond/pdriver_sch.gif

Doug