Help/advice voicing DLite 22?

[dogears]

You can safely have over 300v on the PI plates. I have about 315/308 on one of my amps.

Definately try changing the 18K dropping resistor to a 22K. This will restore the operating voltages to a potentially sweeter range. I wonder where 18K came from. Having 180v-185v on V1 is OK.

One issue is the 6V6 tubes. I am a broken record, but I don't liek them. They always have a harshness to my ears. Maybe try using a set of 6L6 to get a comparison baseline. Remember to change which tap you plug into.

Lastly, some documented 220k plateload amps had 330pf snubbers. You could up them to 330pf. This will make a noticeable difference.

[markmalin]

You can safely have over 300v on the PI plates. I have about 315/308 on one of my amps.

Definately try changing the 18K dropping resistor to a 22K. This will restore the operating voltages to a potentially sweeter range. I wonder where 18K came from. Having 180v-185v on V1 is OK.

One issue is the 6V6 tubes. I am a broken record, but I don't liek them. They always have a harshness to my ears. Maybe try using a set of 6L6 to get a comparison baseline. Remember to change which tap you plug into.

Lastly, some documented 220k plateload amps had 330pf snubbers. You could up them to 330pf. This will make a noticeable difference.

Thanks for the input Dogears.

I switched the 18K to 22K. I also removed the 100 Ohm decade box I had in series with the standby switch, which was lowering the overall voltage -- assuming you were suggesting I get rid of that, too. So in this setup I now have:

V1 p1: 200
V1 k1: 1.6
V1 p2: 205
V1 k2: 1.7

V2 p1: 209
V2 k1: 1.6
V2 p2: 213
V2 k2: 1.7

PI plate 1: 304
PI plate 2: 308
PI cathodes: 55V

My 6V6 plates are now at 446 V

I haven't measured the voltages with my 100 Ohm dropping resistor (temporary decade box) in circuit. Should I do that to see how the overall voltages lower, or is that moot.

I've got to order some 330 p caps to try for the snubbers on V2 - thanks for the tip. I look forward to seeing what that does.

I think I'll order another transformer and try out a set of 6L6's. My current OT can run them, but with a 4 Ohm load and I only have an 8 and 16 ohm speaker right now. I'm real curious to see how 6L6's sound...

Mark.

[heisthl]

I bet the amp sounds better with those voltages, but you might go 1 step further and see if you can get V1 a little lower by reducing the FET simulation resistor (the 150k to ground from B+5 - you do have one don't you?) from 150k to 120k or even down to 100k(don't go below 100K) to shave off another 10 volts or so, this will also lower V2 slightly.

[phsyconoodler]

Sorry Mark!I don't know what I was thinking about the pi voltages.
Mine is currently 310/305.
However,my curent build sounds amazing with 6v6's or 6L6's.Here's an internal shot.If you'll take notice,no orange drops and no vishay dale resistors.

[markmalin]

I bet the amp sounds better with those voltages, but you might go 1 step further and see if you can get V1 a little lower by reducing the FET simulation resistor (the 150k to ground from B+5 - you do have one don't you?) from 150k to 120k or even down to 100k(don't go below 100K) to shave off another 10 volts or so, this will also lower V2 slightly.

I do have the 150K resistor (that's the last one in the string, correct?). I'll ahve to see if I have a 120K on hand.

[markmalin]

Sorry Mark!I don't know what I was thinking about the pi voltages.
Mine is currently 310/305.
However,my curent build sounds amazing with 6v6's or 6L6's.Here's an internal shot.If you'll take notice,no orange drops and no vishay dale resistors.

No sweat -- you had me going there for a minute

Nice work on the board layout - very clean!

[dogears]

Raise the first dropping resistor up a little. I have seen Dumble use as high as 8.2K there. Try a 4.7K

[markmalin]

Raise the first dropping resistor up a little. I have seen Dumble use as high as 8.2K there. Try a 4.7K

I'm placing an order with Mouser today for some 3W resistors and I'll give this a try. Thanks.

Just so I'm clear on this, should I leave the 100 Ohm resistor in series after the standby switch (keeping all B+ voltages lower across the board) or are you saying to raise the first dropping resistor and ditch the 100 Ohm?

Mark.