I'm just finishing off a 300b build with EL33 as a driver tube. Mu is about 20 in triode. Since I now have the octal bases available I'm wondering what else I could use with a gain of at least 20 or preferably higher. Could be a a triode like 6J5 or 2C22 or a pentode/tetrode in triode. I'm not interested in a pentode stage - just triode connected.
Some obvious examples would be 6V6 or 6W6 or 6Y6 in triode, but there must be loads of others that could sound good. I'd prefer a low bias voltage to avoid a cathode bypass cap if possible, and this is where the EL33 is good. Russian 6P9 also has a low bias voltage - same tube as 6AG7, 6AK7. I may not find a better octal driver, but open to ideas.
Suggestions?
Some obvious examples would be 6V6 or 6W6 or 6Y6 in triode, but there must be loads of others that could sound good. I'd prefer a low bias voltage to avoid a cathode bypass cap if possible, and this is where the EL33 is good. Russian 6P9 also has a low bias voltage - same tube as 6AG7, 6AK7. I may not find a better octal driver, but open to ideas.
Suggestions?
Not one.
Get away from it, especially from 6SN7.
Search for a driver with a Loctal socket. Especially Germany or Philips post tube.
Just IMHO.
Get away from it, especially from 6SN7.
Search for a driver with a Loctal socket. Especially Germany or Philips post tube.
Just IMHO.
I agree about avoiding any kind of 6SN7 - in this position we need large output-voltage swings, and these weedy triodes are easily surpassed for doing that.
If you really want octal, try JJ 6V6: you can run high current and get a better grip on the 300B grid.
Or turn up the gain of your op-amp stage, and use a 2A3 as driver. I believe you would enjoy that!
If you really want octal, try JJ 6V6: you can run high current and get a better grip on the 300B grid.
Or turn up the gain of your op-amp stage, and use a 2A3 as driver. I believe you would enjoy that!
Hello Rod. I have a 46 driver in my 300b system right now - very nice. It sounds much better than a 6C4C which I tried (not far from a 2a3) and even better than a 10Y which surprised me.
What I'm trying to do for a second 300b amp is a more simple driver stage with more gain. So indirectly heated this time. Plenty of 9 pin choices - that's not an issue. I'm trying to see what are my choices in an octal socket. Loctal is another possibility but for now I'm just looking at octals.
I hope to get the EL33 (actually PL33) working soon to establish a baseline. After that I could look at 6P9=6AG7=6AK7 or possibly 6J4=6zh4=6AC7=6AJ7. This is just an exercise in curiosity. Not much to do in lockdown.
What I'm trying to do for a second 300b amp is a more simple driver stage with more gain. So indirectly heated this time. Plenty of 9 pin choices - that's not an issue. I'm trying to see what are my choices in an octal socket. Loctal is another possibility but for now I'm just looking at octals.
I hope to get the EL33 (actually PL33) working soon to establish a baseline. After that I could look at 6P9=6AG7=6AK7 or possibly 6J4=6zh4=6AC7=6AJ7. This is just an exercise in curiosity. Not much to do in lockdown.
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You might want to take a look at the 6N7(GT or metal,Western or Russian equivalent 6N7P).Don't confuse it with 6SN7,it's a different tube.
I once had some 6N7 and didn't like it at all - sounded quite dull to me. Others seem to like it better, though. At that time I was using 7193/2C22 which sounded excellent, and better than all the 6SN7s I had including round plate ones, but as stated a bit wimpy for a 300b driver. I might still try it just to see what it gives.
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A 6SG7 with a few mH choke with some iron from the shield to ground would work very well. Don't overpower the grid on a coke bottle tube, it will sound almost as bad as underpowered.
The 6SG7 with mesh shield properly utilized can withstand significant voltage and input grid anode decoupling when properly utilized. Trust me a C3M would be a total waste on a nice 300b or 2A3.
6SN7 will give a lot of good use from a 300B, don't kill our grids!
7N7 or the other industrial tubes mentioned will sound industrial, aka significant 2nd + 3rd order odd harmonics.
The 6SG7 with mesh shield properly utilized can withstand significant voltage and input grid anode decoupling when properly utilized. Trust me a C3M would be a total waste on a nice 300b or 2A3.
6SN7 will give a lot of good use from a 300B, don't kill our grids!
7N7 or the other industrial tubes mentioned will sound industrial, aka significant 2nd + 3rd order odd harmonics.
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I don't really know. 6BL7 mu is lower than what you are asking for, but I got pretty low distortion with CCS load at pretty big swings with it.
I've always wanted to try ECC99, but that's not octal.
I'm not much help.
I've always wanted to try ECC99, but that's not octal.
I'm not much help.