Univalve schematic

[changes]

boy i would kill for a schem of this amp... :twisted:
does anybody have one???

[Regan]

Why bother, they are pretty cheap
also they use custom transformers if I recall.
Besides, THD is a small comany trying to pay the bills,,, better to support these guys so they keep bringing out Stuff  
Regan

[PB Wilson]

I've been looking for a Univalve-type project for a while. Basically a simple-ish amp that allows tube changes without rebiasing. I did find one that came in a kit form from Allen Amplifiers. It's the Class Act II which is a chassis kit that is based on a Marshall amp but allows switching of the input and output tubes. Here's that link. Look for the 5FCA Class Act II Chassis Kit.

http://www.allenamps.com/5f2.html

[Regan]

You could build a high octane from ax84, or a p2 from the same site
both will help get you in the ballpark.
Regan

[PharaohAmps]

I liked the UniValve so much I bought one!  I've built many tube amps for myself and customers, and I thought that the quality and design of the amp were so good that THD deserved my money rather than me copying the amp.  

If you're really serious about building one, they're fairly complicated for a small amp.  Single-ended power section with the cathode resistor chosen as a compromise between several different power tubes, four preamp stages, Baxandall-style tone stack, and a built-in attenuator.  Add to that the ability to switch the plate voltage from the front panel and the light bulb noise reduction, and it's a pretty major undertaking to build one.  If you were really serious you could do it, but I'd rather buy one (mostly cos it looks so cool with the engraved faceplate and that powder-coated tube cage!)

Here's a pic of mine:



The cab is a 1x12" loaded with an Eminence Cannabis Rex Patriot Series speaker.  I'm normally not a huge fan of small closed-back boxes like this one, but it suits the speaker and amp really well.  The Uni can get some pretty major top end, and the C-Rex rolls it off nicely.  I also have a 2x10 with a Ramrod and a Ragin Cajun installed, and it's a lot "barkier"-sounding.  The Uni has a very fast attack at full power and high voltage, and those 10"s really jump

Matt Farrow

[aron]

The univalve is cool and so is the BiValve.

Get a Champ kit and that will get you close. It's cathode bias that allows you to try different tubes. You can also use a variable power resistor (with clamp) to adjust/tweak your cathode bias.

[grs149]

Check out http://www.storm.ca/~rheslip/richsamp.htm for a project amp "inspired" by the UniValve.

You might have to email the guy for his schematic, since the link appeared to be broken when I checked.

gs.