power scaling box?

[arfy]

Anyone installed a London Power power scaling kit in their Express clone? I'd sure like to use mine with a little less volume but a master volume and Weber Mass I've tried so far just didn't do it for me.
London makes a power scaling box for retrofitting into amps that has most of the circuit in the box that mounts outside the actual amp chassis. I think you might not need the drive compensation since if the B+ is reduced somewhere before the standby since power goes to both the OT primary and the 1K/25W screen resistor from the standby.

[Darkbluemurder]

I would be interested in that, too. One of the things that so far kept me from approaching a TW build is that I am afraid I cannot use it because it is too loud.

[UR12]

Anyone installed a London Power power scaling kit in their Express clone? I'd sure like to use mine with a little less volume but a master volume and Weber Mass I've tried so far just didn't do it for me.
London makes a power scaling box for retrofitting into amps that has most of the circuit in the box that mounts outside the actual amp chassis. I think you might not need the drive compensation since if the B+ is reduced somewhere before the standby since power goes to both the OT primary and the 1K/25W screen resistor from the standby.

I have installed a power scaling circuit of my own design in a cathode biased 18 watt amp. The Express will need the KOCs extra bias tracking kit because it uses fixed bias and you will need to vary the bias voltage along with the B+. You can scale just the power amp and not the preamp or you can scale the whole amp. If you do the whole amp a Drive compensation control won’t be needed. Personally I like the way my amp sounds with the whole amp scaled. It would be interesting to see how much of the gain remains in an Express that is scaled. Keep us posted if you try this. I hope to scale my Liverpool soon. It uses cathode bias and doesn’t need the extra Bias tracking circuitry.