hi there, I have a Hiwatt DR103 and I’ve pulled the two outer power tubes to run the amp at 50 watts, which I am then running through a PS100 and into my 2x12 cab wired for 16ohms. The forums I’ve checked say that if you pull the two outer power tubes in a 100 watt amp you should change the ohms on the amp to 8ohms and run it into the 16 ohm cabinet. I’m semi amp illiterate and I want to be cautious, should the ohm selection switches on the PS100 be set for AMPLIFIER: 8 ohms SPEAKER: 16 ohms? Thanks!
You can optimize the impedance match with only two of the four tubes installed by setting the amp to 8 ohms and running it into a 16 ohm speaker cab.
The same goes when you incorporate the PS-100 into the equation. In this case, you would set the Amp In impedance to 16 ohms and the Speaker Out impedance to 16 ohms. In other words you’re treating the PS-100 Amp In (the built in speaker load) as a speaker cab.
Now for the curve ball…
The DR103 derives its signature sound by pushing it up to intolerable volume levels. One way to manage that is to remove two power tubes. That mitigates the kill power, but at the same time kneecaps the ability of the output stage to do the big punchy Hiwatt thing.
The Power Station is designed to allow you to take advantage of the full blown Hiwatt experience without sacrificing the DR103s power tube and output stage behavior. So, I recommend running all four power tubes and let both the DR103 and the PS-100 do what they do best.
Cheers,
Dave
Fair enough! I have some vintage Tung-sols in there that came with the amp (when I got it second hand) so the plan was to pull two of them and save them so that when the first two died I’d still have some juicy vintage tubes ready to go thereby stretching out their life. But I should A/B them with 4 powers tubes/2 power tubes and check out the difference. Thanks for the response!