Dropping B+ in express for 6k6s

[studiodunn]

I'm wanting to run a set of 6k6s in my 6v6 only express and was looking for advise on the best way to do this. The amp currently is running 392v on the plates and I see that a 6k6 needs 315v.

I'm not sure I want to start replacing all the dropping resistors throughout to keep the voltage where it's at downstream.

The amp is pretty true to the Kelly schematic.

[xtian]

You won't get to 315 plates by changing dropping resistors, unfortunately. Look at "MOSFET B+ reducer" -- I've documented this here on TAG.

[wpaulvogel]

What power transformer are you using? If yours has the 260 volt windings it would probably be safe. I had pacific wind me some 200 mA rated 260-0-260 power transformers for EL84 stuff and they make 320 volts with 2 EL84s.

[Mark]

The Zener diode attached to the centre tap of the secondary does work well and might be easier than a mosfet rail reducer.

[studiodunn]

I forgot to report back that the PT did have a 260-0-260 secondary that I wired into a switch so the voltages can be changed for 6k6 or 6v6/el34s.

I love this amp with 6k6s in it. They most definitely knock some dBs off and have a fantastic grind to them. I don't see myself changing them out anytime soon. And they are cheap! I bought a matched sleeve of 5 NOS RCAs for $30
This is just a fun amp that sounds great with any guitar I plug in.