4 output tubes for D-Lite

[secretriches]

Does anyone have an opinion as to whether installing 4 output tubes for the D-Lite build would improve tone in any way? The d-lite works well with JJ 6v6's and I was wondering if 4 of the same would be a benefit. Plates are running about 425v. Since the biggest draw on the heater current is the power transformer, would the d-lite spec'd transformer work well with 4 output tubes?

D-Lite Power transformer specs: 120v primary, 325 V secondary taps @200mA, center tapped (325v-0-325v), 6.3 CT@4A (3.15v-0-3.15v), 5V & 6.3 V @ 3A (5v-6.3v-0).

[Normster]

I've been thinking about doing the same thing. Heater current should be fine since a 6V6 only draws about 0.45A. Figure just under 3.0A total for 3-12AX7s and 4-6V6s. The sticky part is plate current. Max current for 2-6V6s is 92mA on the plates plus 13.5mA on the screens. Add in another 1.2mA for each 12AX7 and you're really pushing the limits of the transformer. (214mA) Of course, you wouldn't be "peaking" the plate current all the time so it still may be OK. On the other hand, a pair of 6L6s is pushing 210mA max plate current plus 22mA on the screens and I've never had a problem running a pair of them in my D'Lite.

On the OPT side, the transformer is going to react much the same as with a pair of 6L6s. Reflected impedance will be 4K instead of 8K so the output selector should be set to "half" the labeled setting. (i.e., 8 Ohm will actually be 4 Ohm.)

BTW tranny gurus, feel free to correct me if I've gotten any of this wrong.

[Normster]

Finally got around to building this circuit. I decided to go with the HRM preamp, 4k OPT, and 4 x 6V6. Very punchy sounding amp with nice thick mids. I've still got some minor tweaking to do, but overall I'm really pleased with the build.

[Bob-I]

Finally got around to building this circuit. I decided to go with the HRM preamp, 4k OPT, and 4 x 6V6. Very punchy sounding amp with nice thick mids. I've still got some minor tweaking to do, but overall I'm really pleased with the build.

I'm thinking of the same thing, but my calculations didn't match yours. I calculated 80ma for a pair of 6V6's, so 160 for 4. Am I that far off? If I am then my design for a 5-12AX7 amp with 4 6V6's won't work with a 200ma PT.

[BobW]

Norm, Great layout and build, as usual.

What's your take on the 4 6V6 vs. the 2? I am happier w/ 2 6L6's (gig volumes, etc) but a 4 6V6 may be the ticket. thanks

[Normster]

Bob-I, I think you'll be fine. I don't know if my calcs are correct either, but the PT barely gets warm after playing for 2 hours. (Of course, when I load it into the head cab, those 4 6V6's radiate a bit of heat. )

BobW, it's hard to compare the 2 vs 4 6V6 config since I used a different preamp design in this one. (Although I guess I could just pull a couple of tubes to find out.) The amp does have a lot more thump than any of the D'Lites I've built...and it's definately louder!

Moss has a build underway using a Bassman-style OPT with 6L6's. When it's done I'll do a compare and report back.

[klingo]

Hi!
I have a question

my next amp will burn a quartet of 6v6
with SS rectifier
is a 300v/0/300v CT 200mA secondary winding feeding the two diodes the same as a 300v/0 400mA feeding a Graetz bridge.

I assume that 600V200mA or 300V400MA are both 120VA, but who knows???

cheers

Olivier