trinityamps.com

Looking to DIY build a Triwatt and have a few starting questions. First, I won't have a need to run 16 ohm speakers (or multiple speakers), so can I eliminate: R36. Second, what are the voltage ratings of C18 & C19. And third, what is the approximate size of the standard Triwatt enclosure/case (aluminum)? Thanks.

You can't eliminate R36, as that's the feedback loop resistor. It's only about worth around 20 cents anyway. C18 and C19 are 450V rated or higher. IIRC the aluminium chassis is IIRRC 20" X 6.5" X 2.5". If you want to get the real deal Hiwatt tone, it's also recommended to buy Trinity's Triwatt transformer set. HTH

_________________
Great tones come in small glass jars!

Would a 820k resistor work fine for R44 (the alt. says 910k, that's a big jump)?

No, that resistor sets power tube bias voltage and you will very likely have biasing issues. Basically, you have to stick to what's shown in the drawings.

What is your experience in amp building BTW? The Triwatt is a fairly advanced build....

_________________
Great tones come in small glass jars!

I've built a number of electronics devices (headphone amps, speaker amps, DACs, microphones, etc...), but my understanding of circuitry is still very moderate. I'll admit a lot of projects I've built are a lot more documented, including circuit design, component selection, and BOMs.

I'm slowly learning circuity and understanding of schematics (other than just reading them and building a circuit).

It seems to me that in one position (tube selection switch, KT66 vs. 6V6) the two resistors (R43 & R44) are in parallel, and in another only one (R43) is connected.

So the schematic says 910k is an alternative, the difference seems small to be (180k & 620k = 140k, vs. 180k & 910k = 150k, vs. 180k & 820k = 148k ). If I understood what was going on (dropping voltage from PT ~ 350VAC?), I could make an educated guess...

Educated guess' in high voltage work can get you dead really fast. I work and teach high voltage and there are two main rules:
1.When powered up work with one hand, DO NOT GROUND SECOND HAND!!!!(put it in your pocket and hang on to the little guy)
2.When in doubt ask, don't guess

These voltage and current levels are great for inducing fibrillation
or to cause burns that will not heal correctly
It gets hard to play stringed instruments when you burn/blow the fingers off your hand because you guessed wrong! The internet is a great resource use it. There is a thread on this site that lists some really good resources for learning use them.

_________________
Fantasy Noise is what my shop of dreams is called and was the only way to beat my addiction, like many here I suffer from G.A.S.


Tele's make the best noise

Correct.

Yes, your logic is along the right lines. Also look at the little network of resistors and bias pot that come after. The tricky part is getting a usable bias range out of the 10k pot for the given type of tube. Personally, I would have preferred a 20k pot (with suitable alternative resistor values), but 20k pots without a shaft proved difficult to find. You're welcome to experiment with the values if you want, but you will need to keep a real close eye on the power tubes, so they don't melt down in the process.

_________________
Great tones come in small glass jars!