Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: AmberB on March 22, 2024, 06:28:28 pm
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Does anyone use the 6K6 tube for anything anymore?
I've got at least 8 of them...
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It goes in the 6G15 reverb circuit.
All I got.
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You can build any single-ended or push-pull circuit you like. Use in place of the 6V6, but keep the voltage reasonable/low, and if you want to optimize power output then raise the load impedance a little compared to 6V6.
Or you could send them to me, as I've got an old 6G15.
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using them in in a guitar amp, turned audio amp currently (the 6W6 in the pic is a "pin stretcher" for soldering)
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I have used them on occasion. Typically with a 275-0-275 or 300-0-300 PT and a 5Y3 rectifier.
https://soundclick.com/share.cfm?id=11527276
With respect, Tubenit
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Nice playing Tubenit
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I have used them on occasion. Typically with a 275-0-275 or 300-0-300 PT and a 5Y3 rectifier.
https://soundclick.com/share.cfm?id=11527276 (https://soundclick.com/share.cfm?id=11527276)
With respect, Tubenit
That sounds very nice.
Planted the seed for a 6K6 P-P "Champ"...
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From what I can find about the specs of the 6K6, it seems to have more or less the same heater current as the 6V6 and 6AQ5, a bit higher mas plate voltage than the 6AQ5, and about the same power as the 6AQ5 and the 6V6 when it's run at the same plate voltage. It does seem to need a higher resistance cathode bias resistor than the 6V6 or 6AQ5, but that's a simple thing. It seems like a 300 volt plate voltage would be just about right for the 6K6.
I guess I need to test these tubes to see if they're good. I actually found 2 more in my tube caddy that are still in their boxes.
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The 6K6 does have a higher plate load than most tubes. It's a little trickier to find a matching OT.
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FWIW;
here's the link to my tinker'n amp
https://el34world.com/Forum/index.php?topic=25104.0
I did both a 6K6 and 6V6, switched bias, speaker load to "compensate" for differences.
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The 6K6 does have a higher plate load than most tubes. It's a little trickier to find a matching OT.
It actually is "simple": Just use whatever you would use for 6V6. You simply won't maximize power output.
The 6K6 data sheet (https://frank.pocnet.net/sheets/093/6/6K6GT.pdf) shows a max plate & screen voltages much like 6V6 of the era, but only 8.5w plate dissipation. Assume the 6K6 likewise passes 8.5/12 = ~71% of the plate current that the 6V6 passes.
Ohm's Law: Resistance = Volts / Current
Plate Load ---> Volts / ↓ Current = ↑ Resistance
So we could figure "6V6 plate load" / 71% = 8kΩ / 0.071 = 11.3kΩ ----> plenty close to the 10-12kΩ seen on the data sheet.
But we also don't need to have a perfect plate load, and our "penalty" would be slightly less clean power output. This is shown in the Blue line (8kΩ OT for 6V6) vs the Red line (12.5kΩ ideal 6K6 load) delivering about 25% less-power. That's probably very desirable for this true-pentode 6K6...
(https://i.imgur.com/DK061oJ.png)
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6K6 is a type 41 on an Octal base. '41 was the first "good" power pentode. 6V6 is "clearly" an improved 6K6. EL1 and EL2 also seem to be reading the '41 spec sheet.
Tubes is tubes. Within ratings, and intelligently designed, there won't be a heap of difference. Designed by rumor and guess/gosh, you may hit on a case that "adds tone".