I've got an Ampeg Jet amp that I really like, but I have to crank it to get preamp and power tube distortion (it has no master volume).  It also only has one tone knob, which limits my options as well.  I've thought about modding it and adding a master volume and a Vox tone stack so that I can get some tube distortion at lower volumes, but I'm not crazy about  the idea of hacking it (the amp) up.

I'd like to try and build a preamp that will give me some nice tube distortion - doesn't have to be super high gain.  Are there any designs that are "fairly easy" out there?  Doug Hammond's Pentode Driver looked pretty interesting, but I'm not sure how hard it would be to build something like that.  As far as making it sound more like the Vox, I can probably just substitute (or add) the Vox tone stack to any design.  I'd love to just build the preamp of into a pedal, but I'm not sure if that's possible or "what blanks would need to be filled in" to make it work.  So I'm assuming that something along the lines of the Pentode Driver would be better, as the details are all laid out.

Any ideas/suggestions?

Have you tried goosing the amp with let's say the AMZ Booster?.
Do you know how to work with high voltages?.
If you do let me know and I'll get you some links.

Aharon

Aharon,

Thanks for the reply.  As far as working with high voltages, I'm not sure if I know everything I need to know.  I've just started experimenting with working on tube amps and I know how to discharge the caps, but that is the extent of my knowledge.  If there's more that I need to or should know, please let me know - I want to learn as much as I can about these types of things.  Any resources I should look into?

I had a booster, but it was stolen - I'm pretty sure that I tried it before hand and it didn't work too well, since I still couldn't get a good amount of distortion at bedroom volumes.  Plus, I really want to learn more about working with tubes.

also - is the PentodeDriver a high voltage pedal?

The Pentode Driver is a 15V pedal(low voltage)but you need a transformer that's connected to the mains which is 115V.
If you want to learn more go here and ask/ read all you can.
http://ax84.com/bbs/

Take care
Aharon

Aron released a design a while back called Shaka Tube. The schematic looked relatively simple and the sound clip sounded fantastic. It was definitely within the low- to medium-gain range with what sounded like a lot of sustain for the amount of drive.
It used a 12V supply if I remember right, so it could be ideal for someone looking to (safely) get started with tube overdrives.

Here's the schem:
http://www.diystompboxes.com/pedals/schems/shakatube.gif

Here's a pictoral of the project: http://home.att.net/~u2p0j0m3/Bulldog.htm

that sounds perfect for what I'm looking for - I'll see if I can dig up the sound clips.

what about the TubeDriver?  Anyone tried this?  It runs on only 9V.

I'm not horribly impressed with the Pentode Driver anymore, but that's me, I'm a fickle SOB... :wink:

(I get that way about my older stuff sometimes- there's this learning curve I'm on and all...)

It has a punchy compressed response and thumping bass, but the distortion needs smoothing out. Another problem with it is that with AC tube heaters it is kind of noisy. It hums more than I like. If I remember, Aron worked out a DC heater scheme for his Shaka Tube and I bet it's pretty quiet. The Pentode Driver and Shaka Tube were both derived from the BK Butler Tube Driver (30v version- well... +-15v).

I may go back and try to "fix" the Pentode Driver someday but not now.

Anyway, the BK sounded great to me on the breadboard (except for that AC heater thing) so I would check out Aron's Shaka Tube for a good starved-plate tube pedal. His sound clip is really nice!

Doug

Thanks, Doug!  I'll go with the Shaka Tube.  Anyone know where the sound clip is?

I knew how to get to it (a soundclip) at the old forum...  

That pictoral link above is a link to my page about my Bulldog pedal. I have to rework it sometime. Putting the transformer inside the enclosure causes some problems with hum. I am going to use a AC wall wart transformer instead. Got it a thrift store for $1.00

The Shaka Tube is a nice sounding little tube distortion circuit.

anyone have opinions on the "Real McTube"?  

http://www.dogstar.dantimax.dk/tubestuf/mctube.htm

Here's the demo song:

http://www.diystompboxes.com/pedals/sounds/shakaTubeDemo.mp3

that soungs GREAT.  I can't wait to build one now!

Yeah, that clip sounded even better than I remembered.

SFR, I love my like Real McTubes - built two of them (one with 12ax7 and one with 12at7).  Fred Nachbaur is a really nice guy with a great website.   He helped me with several debugs.  This was the first effect I made. I think it would be a really easy and inexpensive project if you already have alittle experience building effects, and can get your hands on some spare parts.    Sounds great with my Rangemaster clone and a Vibrochamp!  I made mine from schems using point-to-point wiring but there is now a pcb layout available at Tonepad I think.  It won't get metal distortion but does go from alittle warm, to really crunchy.   Its also a great boost.  When I tried my mctube next to a tubescreamer with the jrc4558 mod, I REALLY preferred the mctube.  That tube sound we crave is DANG hard to imitate with a direct comparison, IMHO.

MartyB,

for your mctube , what was your B+ 140 or 200+ ??

can I use the mctube alone as a tube distortion?? does it really go HEAVY distortion?? or just Grunge??  



-Ralph

Im looking for a high-gain tube effect..any opinions or ideas?