Yep (attached) With RL= 500R, the power would be reduced somewhat, but the distortion performance would likewise improve. The nice things about these types as audio finals is that you can get bigwatts without having to resort to excessive voltages and deep Class AB operation. The only downside is expense and availability, but the latter concerns are answered by the wide variety of non-standard heater voltages.6LW6s are rarer than seal feathers these days, and $PRICEY if you can find them. 36LW6s, OTOH, are readily available, and none too expensive -- much less than a lot of audiophool expensive tubes. There are other odd heater voltage varieties as well.
That'd be fine, though my preference would be the cascoded 6BQ7 LTP front end that I did for the Le Renard. It's one stage that gives enough open loop gain for sensitivity even with gNFB. It's also an excellent performer, very low distortion and with excellent AC balance. I would also include grid drivers even though it's not a difficult load for protection against blocking.
As for lNFB and HD finals, it's not a prob since it's not necessary. These types make good sounding audio finals even before you apply any NFB, and all that's really necessary is enough gNFB for damping and taking the "edge" off.
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i am having issues with the 6CL6 btw, it goes into current hogging
mode after a while and plate voltage drops low.....
a look at the datasheet revealed that you need to use lowish
grid leak resistors....so i did...but till have the same issues
although not as prevalent as before...
any body else noticed this? any suggestions?
i am inclined to replace it with another type....
RE: Mona Ketje
"Why not consider a circlotron ? It gives a combined action of UL and CFB.
And it's not always the same over and over ..."
Floating B+ supplies = pain
Try Elliptical Twin instead, only 28% CFB too, using off the shelf UL OTs.
(a variant of Norman Crowhurst Twin Coupled Amp. )
More 6/26LW6 data_curves.
Some local Fdbk amp ideas. Too keep the output impedance low (a high damping factor for hard to drive speakers)
http://www.dissident-audio.com/Yves/1960crowhurst.pdf
Another tube for list: http://frank.pocnet.net/sheets/049/6/6MC6.pdf (36MC6)
"Why not consider a circlotron ? It gives a combined action of UL and CFB.
And it's not always the same over and over ..."
Floating B+ supplies = pain
Try Elliptical Twin instead, only 28% CFB too, using off the shelf UL OTs.
(a variant of Norman Crowhurst Twin Coupled Amp. )
More 6/26LW6 data_curves.
Some local Fdbk amp ideas. Too keep the output impedance low (a high damping factor for hard to drive speakers)
http://www.dissident-audio.com/Yves/1960crowhurst.pdf
Another tube for list: http://frank.pocnet.net/sheets/049/6/6MC6.pdf (36MC6)
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If you have the regulated volts needed, try the 6922 cascode I've uploaded. A possible improvement is a small ferrite bead around the socket tab of the "upper" triode's grid. FWIW, I dislike the idea of a the "upper" grid not being at AC ground.
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Since it is a grounded grid config
Probably like this no adjustement is needed nor a stabilised supply.
Mona
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If you mean minimal hum equals regulated, then yes, but I think it's only an easy way to get therePSRR in cascodes is non-existent.
.The same hapens with penthodes.
By deriving the grid voltage from the anode voltage the devision of the voltages among the triodes is fixed (give or take a little Vg change), does not depend on the supply.
Mona
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