Which vvr for trainwreck rocket

[JoshBernstein]

Im looking to install a vvr in my trainwreck rocket, but im not sure which one to go for. The only source i know of is london power, but they have a couple different ones for cathode biased amps. Id only want to use thr vvr for the power tubes. Any suggestions would be appreciated, or a diagram or something on how to install one would be great. Thanks!

[xtian]

The Rocket is cathode biased, which makes the VVR circuit the easy one. I built my own, based on Hall's VVR:

https://tubeamparchive.com/viewtopic.php?t=28653

Very easy, very good.

[JoshBernstein]

Thank you, thats very helpful. I only would like to control the power tubes' voltage, would i have to build 2 of these? One for the screens and one for the plates?

[xtian]

No, you don't have to build two. Hall's PDF has instructions for scaling only the power section, I think...

[sliberty]

I've used the Hall VVR in a Rocket, and it worked very well. I scaled the whole amp however. I found it to be very transparent for small to medium reductions in volume (voltage). Of course once you take it way down, things change...

Lots of good info in Hall's manual about how to install, and any pitfalls and workarounds.

[JoshBernstein]

I ended up ordering a pcb from dana hall, and im currently looking at mosfets. The nte2377 is pretty expensive. Is there anything that would cost a little less and still be sufficient for the rocket?

[xtian]

Post #4 in my thread.

http://www.farnell.com/datasheets/1690310.pdf

Less than $3 at Mouser.

[JoshBernstein]

I did see that, just wanted to make sure it would be sufficient for 4 el84s

[xtian]

Yes, that MOSFET is over spec'd. Just make sure to mount it against the chassis, using a mica insulator and some heat sink grease.