I know, risky business getting me thinking about things but...
This thread on the 6V6 preamp
6V6 line preamp
got me to thinking about other power tube preamp options. It occurs to me that the vertical sweep tubes like 6EM7/6GF7 could be used for some interesting variations on the theme.
You could use the power triode section much like the trioded 6V6 above and then use the extra small signal triode as a cathode follower to drive a subwoofer amp. So you get the nice no FB low mu preamp for the main amp and a "free" subwoofer output in one bottle.
Alternately you could make a remote preamp capable of driving very long cables where you want the control amp located a fair distance from the power amp. In this scenario you use the small signal triode with local feedback for the voltage gain and the power triode as a heavy duty cathode follower. This section used as a CF can provide a lot of drive into highish capacitance due to the low Zout, high driving current, and relatively small cathode resistor.
P.S. The 6080 looks like it might be fairly linear at preamp level voltage swings.
This thread on the 6V6 preamp
6V6 line preamp
got me to thinking about other power tube preamp options. It occurs to me that the vertical sweep tubes like 6EM7/6GF7 could be used for some interesting variations on the theme.
You could use the power triode section much like the trioded 6V6 above and then use the extra small signal triode as a cathode follower to drive a subwoofer amp. So you get the nice no FB low mu preamp for the main amp and a "free" subwoofer output in one bottle.
Alternately you could make a remote preamp capable of driving very long cables where you want the control amp located a fair distance from the power amp. In this scenario you use the small signal triode with local feedback for the voltage gain and the power triode as a heavy duty cathode follower. This section used as a CF can provide a lot of drive into highish capacitance due to the low Zout, high driving current, and relatively small cathode resistor.
P.S. The 6080 looks like it might be fairly linear at preamp level voltage swings.
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Consider the 6C4C as a preamp tube. I've tried it and liked it. Maybe not as much as 46 or 10Y but this is a $40 tube and quite plentiful. It's a good sounding 6B4G variant with an octal socket. I'd certainly use it instead of a 6V6.
Needs DC filaments, preferably with Rod Coleman regs. But otherwise quite easy to implement, easier than a 2a3 unless you use AC with that. I'd use a plate choke and DC Link bypass caps. You should get very nice sound and it would drive anything.
Needs DC filaments, preferably with Rod Coleman regs. But otherwise quite easy to implement, easier than a 2a3 unless you use AC with that. I'd use a plate choke and DC Link bypass caps. You should get very nice sound and it would drive anything.
6AH4 is also a good candidate, a smaller sibling of 6CK4 vertical triode.
6DN7 is kind of half 6SN7 and half 6BL7, used in MFA Luminescence preamp's line stage. It's the lower gain version of 6EM7.
6DN7 is kind of half 6SN7 and half 6BL7, used in MFA Luminescence preamp's line stage. It's the lower gain version of 6EM7.
Here is my list of dissimilar dual triode tubes, I'm sure I missed a few. I was on a spud breadboarding binge a while back.
View attachment DissimilarDualTriodesForSpudAmps.txt
View attachment DissimilarDualTriodesForSpudAmps.txt
You might add the 12DW7, which is still in production. It is half 12AX7 and half 12AU7.
