Can I use 6v6's in a 69 Super Reverb ?

[hebaton]

Wondering if I could run 6v6's in a 69 Drip edge super reverb that was reverted form AB568 to AB763
ANd if, so, would there be a significant difference in volume/ headroom. I am assuming I would be getting breakup at lower volume ???

[martin manning]

The AB568 schematic shows 465V with a very lossy 5U4GB, so the voltage is a bit too high for 6V6, and it will be even higher with the reduced current draw.

[Stevem]

The only time I used 6V6 outputs at that high a voltage was in a Highwatt 50, and they where JJ brand since they are stated to be good up to 500 volts, and after having them in the high watt I do not question that.

[martin manning]

JJ 6V6S could probably take the voltage. Need to disconnect two of the four speakers to increase the load to 8k.

[R.G.]

"Can I use them?" is not the question. Of course you can.

The question is how long they'll last.

[johnnyreece]

Maybe swap in a 5Y3 or 5R4 with the JJ 6V6?

[hebaton]

Maybe swap in a 5Y3 or 5R4 with the JJ 6V6?

I was thinking about that also. Anyone else want to comment on that idea ?

[hebaton]

JJ 6V6S could probably take the voltage. Need to disconnect two of the four speakers to increase the load to 8k.

Would that not result in a 4ohms load ? Or am I refering to something different here ?

[Stevem]

If you start reducing the power supply voltage enough then what you like about the amps preamp section will be lost and at that point your truly better off to keep the amp as it is and open up your wallet to get a attenuator box on the output of the amp.

[martin manning]

JJ 6V6S could probably take the voltage. Need to disconnect two of the four speakers to increase the load to 8k.

Would that not result in a 4ohms load ? Or am I refering to something different here ?

Yes 4 ohms load and 8k impedance on the OT primary for the 6V6S.

Maybe swap in a 5Y3 or 5R4 with the JJ 6V6?

I was thinking about that also. Anyone else want to comment on that idea ?

5Y3 would probably lower the voltage, maybe 25V. 5R4 is a ruggedized 5U4, so no difference there.

If the goal is to reduce output power, I'd leave the power section as-is, and add a master volume, which could be located in the extension speaker jack position.

[lonote]

If the goal is to reduce output power, I'd leave the power section as-is, and add a master volume, which could be located in the extension speaker jack position.

I did just that in a Bassman recently.

Added a LarMar with the control on the back, in the EXT Speaker position. Works great, completely reversible.

[johnnyreece]

Maybe swap in a 5Y3 or 5R4 with the JJ 6V6?

I was thinking about that also. Anyone else want to comment on that idea ?

5Y3 would probably lower the voltage, maybe 25V. 5R4 is a ruggedized 5U4, so no difference there.

Respectfully, I believe the 5R4 has a higher voltage drop than the 5U4.

[martin manning]

You are correct! ~12V higher at 200 mA.

[JD0x0]

Don't forget you need 10x power to double volume, which also means you need 1/10th power to half the volume. I don't think the power reduction will make much difference in volume. Both setups would be loud when pushed.

[hebaton]

Don't forget you need 10x power to double volume, which also means you need 1/10th power to half the volume. I don't think the power reduction will make much difference in volume. Both setups would be loud when pushed.

BUt with more sag ( different rectifier ) and two speakers disconected, would I not get both earlier breakup and lower volume ?
Another question is will I need to mod the bias supply and, if so can I still get enough range to be able to return to 6L6 when wanted ?
Also what If I connected a 8ohms load ?