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I have been digging around in the forums looking for info on running 6v6s in PP or PPP and found that Kondo for a time made a PPP amplifier with 6v6s:
Does anyone have a schematic for that? Or any other PPP schematics for 6v6?
Also, on a separate note, has anyone built a push pull transformer coupled amp with 6v6s?
Thank you and have a wonderful rest of your day!
I did push-pull-parallel ULTRALINEAR with similar tubes. In ultralinear, all you have to remember to get it to work right is do NOT neglect the screen resistor, use about 1K or 1200 ohms on each screen. This forces the tubes to power share appropriately and you will not need anode resistors. if you are doing it ultralinear, I can help you out. I have never built one any other way.
I only use Edcor and I would use 5K. for audiophile, it is okay to go a bit higher in impedance, it makes for better sound. for guitar amps, the opposite holds true. I made a 6V6 amp with the Conn organ schematic and hammond ultralinear 10K 10 watt transformers and it sounds good. I modded the schematic to use 6SN7 and can supply you all the proper values. it is a very simple build and works very well.
I built a pair of PPP transformer coupled KT-120 mono-blocks. 37W of forced class A triode power. Do a nice job of heating my listening room in the winter, not so great in the summer.
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
Hammond Organ developed a PPP amp with 6V6 in late 1930 as replacement for PPP amp with 2A3 tubes, which were then falling out of fashion. You can find schematic on pp.3-41 to 3-43 of the Hammond service manual (link provided). It has differential driver and cathode feedback from OPT secondary winding, as well as impressive choke input power supply with PIO filter capacitors. I have one of those, it sounds really good.
I have been using a PP 6P14P-EV amp for a while with this external power supply and a similar front end topology to this one. I was lucky enough to purchase on epay 13 NIB National Union 6V6s for $265 recently so will go ahead with plans to build a PP 6V6 amp. This PP 6V6 amp clearly derives its inspiration from "El Cheapo."
Output transformers will be UTC LS-63 and the CCS is from K&K Audio. The top plate will be machined by Front Panel Express and the chassis from Landfall Systems. The 6.3V transformers will be on the amplifier chassis not the PS chassis. Since I have not built the 6V6 version yet, the expected voltages and currents are derived mathematically, not empirically, so may change slightly.
It would be difficult to build a feedback amplifier with transformer coupling.
The Bonavolta audio site has a number of schematics using 6V6 outputs.
Buy Chinese. Bury freedom.
Do you guys have recommendations for a ppp output transformer? Based on a pp 6v6 output impedance of 8-10k I think the ppp transformer needs to be 4-5k. Also, are there recommendations for operating points?
Have built PP 6V6, and used the 6V6 as a signal tube( pentode rigged, long tail pair circuit, and liked them a lot. The 6V6 amp eventually became directly heated to run 2E24's and the 6V6 is a little light on gm( and therefore gain ) so the amps now run 6CL6's for the input/phase splitter.
For PPP, find the RCA SP20 schematic. Very nice sounding amp, along with its single pair little brother the SP10.
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Thanks guys for chiming in! Have any of you run a 6v6 as a triode line level preamp tube?
I'm having difficulty finding the schematic for the SP20 and will continue looking.
Have a wonderful rest of your day!
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