6v6 Plexi
Moderators: pompeiisneaks, Colossal
Re: 6v6 Plexi
You should be able to install a set of JJ 6V6 tubes and just rebias and be good to go I believe. I suggest JJ because they handle high voltages very well... That voltage isnt very excessive like some of the older JTM100 Marshalls... It's possible you might need a different value resistor and or trimpot in the bias circuit to get enough range to cover all the tube types.
Re: 6v6 Plexi
You can install some JJ 6V6's and rebias - keep in the mind the quality and reliability as of late with JJ's has not been good.
Naturally your OT is not designed around 6V6's so there will be a tonal compromise there but aside from that, the amp will over drive a easier and will go into power tube distortion sooner, which may be very desireable depending on what you are going for sonically.
Hope it helps
Trace
Naturally your OT is not designed around 6V6's so there will be a tonal compromise there but aside from that, the amp will over drive a easier and will go into power tube distortion sooner, which may be very desireable depending on what you are going for sonically.
Hope it helps
Trace
Re: 6v6 Plexi
+1, the JJs will take the voltage. I also have used NOS 6V6s in mine (~430 plate volts), but had to bias them really cold to keep the screens from lighting up. 
--mark
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Re: 6v6 Plexi
I converted a JTM50 to 6V6s and used a 5U4 to knock down the B+ a little bit more and it freakin rocks.
You may have to switch the resistor and pot values in the bias circuit (bigger pot, smaller resistor) to get it to bias low enough for 6V6s. I had to do that on the one I did. It sounds great.
Since the plate Z of a 6V6 is nearly 2x that of an EL34 you probably will want to run the amp with the impedance selector switch set for half of the real load. So if you have a 16 ohm speaker, put the amp on the 8 ohm setting when running 6V6s.
Since you're talking plexi, and SS rect, I point out that the PS is going to be loaded less in terms of B+ current and this may have a ripple effect of increasing B+ all the way through the circuit. Easy way around this is to put in some series R in the B+. Maybe 100-150 ohms or so to get the amp to feel and respond like a plexi with EL34s, including sag and dynamic feel. Otherwise it may feel kind of "stiff" with the 6V6s. You can put this series R in there and put a switch across it to short it out when you put EL34s or 6L6s back in.
My 6V6 JTM50 is a real animal when it's dimed. It's also for sale, BTW. Currently on loan to a potential customer.
You may have to switch the resistor and pot values in the bias circuit (bigger pot, smaller resistor) to get it to bias low enough for 6V6s. I had to do that on the one I did. It sounds great.
Since the plate Z of a 6V6 is nearly 2x that of an EL34 you probably will want to run the amp with the impedance selector switch set for half of the real load. So if you have a 16 ohm speaker, put the amp on the 8 ohm setting when running 6V6s.
Since you're talking plexi, and SS rect, I point out that the PS is going to be loaded less in terms of B+ current and this may have a ripple effect of increasing B+ all the way through the circuit. Easy way around this is to put in some series R in the B+. Maybe 100-150 ohms or so to get the amp to feel and respond like a plexi with EL34s, including sag and dynamic feel. Otherwise it may feel kind of "stiff" with the 6V6s. You can put this series R in there and put a switch across it to short it out when you put EL34s or 6L6s back in.
My 6V6 JTM50 is a real animal when it's dimed. It's also for sale, BTW. Currently on loan to a potential customer.
6v6 plexi
Looks like I,m going in the right direction. I put a 150 watt 10 ohm resistor in series with the b+ and added a change from split to shared cathode on V2 on the same switch. Should give me a jtm45/plexi option which will also make the 6v6's run a little smoother. Glad that it will sound great in advance of getting it all together, which should be this weekend.