VVR question

[Michael Allen]

daz, you might have a jacked up MOSFET. They are sensitive to electrostatic shock and heat. I'm sure you're aware of this...

No need to buy NTE parts. That may be what Dana used, but NTE are not as good quality and much much more expensive. Look at the data sheet and compare to other Mosfets. Like Bruce said, you can use anything with adequate power/voltage/current handling. I just bought a few STW18NK80Z from Mouser. They're 800V drain-source voltage, 19A continuous current, 350W. Anything above 600V and 200W should be fine... and better than NTE.

HTH, check out the ampgarage forums. Dana is regular there and has posted the cathode bias schem in one of the threads.

[bnwitt]

To be 100% honest, I can see where this circuit could be attractive to some but I'm not knocked out but the whole thing anyhow.
I prefer a more natural approach with smaller amps and smaller power levels, over driven to get that sound... I guess what I'm saying is that a true craftsman has quite a few tools in the tool box... not just one or two that ultimately, do everything equally mundane.

Boy, you hit the nail right on the head for all attenuation and power scaling devices with that comment, as well as for swiss army knife frankenamps that supposedly do it all.

[Michael Allen]

also, to answer your question in the first post:

you can simply T-off the last can, one branch going to the VVR to the power amp, and the other branch going to the preamp/PI. So the B+ going to the preamp and pi is still running through the can caps and choke and is full voltage, and the B+ going to the PA is VVR'd.

[daz]

also, to answer your question in the first post:

you can simply T-off the last can, one branch going to the VVR to the power amp, and the other branch going to the preamp/PI. So the B+ going to the preamp and pi is still running through the can caps and choke and is full voltage, and the B+ going to the PA is VVR'd.

Well, thats what i did except i used the diodes and a seperate cab. But either way i don't see why it shouldn't work.

daz, you might have a jacked up MOSFET. They are sensitive to electrostatic shock and heat. I'm sure you're aware of this...

I know, but it's not fried because i put it back to scaling the whole amp and it works fine.