D'Lite 44 Voltages

[Structo]

I had my chassis out yesterday and did some quick voltage measurements.
I rewired the presence control to correct Dumble spec.
I should have recorded all the voltages for reference but I didn't......

V1 and V2 seemed to be within the range I heard was good (around 200v).
But on V3 (PI) it seemed to be in the 340v range on the plates.
That's a bit high isn't it?
I think I have read that the PI should be around 280v range.

So, is the resistor to look at for this, the 1K on the filter board?
And what would be the correct value to use on that?
Thanks.

[dogears]

I have jumped up and down in the past regarding the 1K value.... The correct value on most Dumbles is in the 3K to 3.5K range. Never 1K.

Try something larger to bring the PI down to 300V or so.

[Structo]

Thanks Scott, that's what I was thinking too.
Now I have to figure out what value of resistor to use there.

Is there a formula to figure out the correct value or is it a guessing game for the value to get the desired voltage?

[tele_player]

Ohm's Law gets you in the ballpark.

[Structo]

Or would it be better to change the plate resistors on the PI?
I have 100K/ 82K there now and I see on the tweaked schematic it calls for 110K/ 100K.
Along with a 3K dropper on filter board.

In looking at the schematic again, wouldn't changing the 1K resistor to 3K in the dropping string drop all the succeeding voltages for V1 and V2?

[dogears]

Definately change the PI plates. 110K/120K if no trimmer. Dumble never used 82K and 100K as far as I know. Changing the 1K would indeed lower the other voltages. But, that is the accurate thing to do. 1K is wrong. If you want more juice on the preamp, change the 22K to an 18K or something along those lines.

Or would it be better to change the plate resistors on the PI?
I have 100K/ 82K there now and I see on the tweaked schematic it calls for 110K/ 100K.
Along with a 3K dropper on filter board.

In looking at the schematic again, wouldn't changing the 1K resistor to 3K in the dropping string drop all the succeeding voltages for V1 and V2?

[Structo]

I also picked up a new choke resistor the other day, a 330 ohm 10 w.
So should I change that, then see what the voltages are before changing the dropping string further?

I had the chassis out yesterday but didn't feel like pulling the boards as I will have to probably remove a lot of wires to properly change components.

[heisthl]

Make 1 change - listen to the difference. Repeat as needed. Seriously change the 1k to a 3k (or 3k3) ignore the lowered V1 and V2 voltages until you play it. They sound good lower and may change your Strat OD tone to your liking.

[greiswig]

I got a little freaked out the other day...when trying to track down the source of the fizz on my OD channel, I put in a new JJ tube in V1, and my voltages dropped to the upper 140's. I thought I'd screwed something up, but I put back the tube that was in there before (a different JJ) and the voltages went back up to the 190's.

[odourboy]

+1 one that... only it was Sovteks for me.

I did a test of all the preamp tubes i had kicking around. I got a variation of about 20 volts on the plates depending on which tube.

tip: it's sometimes easier to swap a 12AX7 than mess with the dropping string to adjust your V1 and V2 plate voltages!

[Structo]

That's good to know in case a person tries to chase his tail.
I know that preamp tubes can make or break an amps tone.
But I don't think I had heard that the voltages can change with different ones, thanks for that.
Right now I have the tubes that Moss sent with the kit.
Two Russian EH 121ax7's and a JJ ECC83 S for the PI.
TAD 6L6GC-STR for the outputs.

When I was younger I had a couple different Fender tube amps but didn't mess around with them internally.
Then I got married.......
So didn't really get back into my guitar stuff until about 10 years ago.
I bought a Carvin Belair a couple years ago and while the clean on that amp is great the OD channels sucks and sounds like mud.
There is that Hasserl guy that has some mods for them that is supposed to clean up the soak channel. I just haven't got around to it....

But building an amp from the ground up has interested me for several years so I bought the D'Lite 44 to get my feet wet.

[burnt fingers]

When I first fired up my dlite I had the JJ in V1 and there was no sound at all. I just swapped with the Sovtek to the PI and it worked. I tried several tubes and did not have that problem, but the JJ refused to play in v1. I think I just quit trying to figure it out.

Lately I've been making the changes recommended by dogears and likeing every one of them more than the last. I do suspect the non-coax on the MV/fx loop is picking up noise but only when the MV is cranked - and I don't crank it.

I did not like the skyliner eq before lowering the choke resistor and modifying the PS string. But after changing the string the amp just bloomed.

I'm taking a hard look at the stock PI plates and considering the trimmer.
I've got a 4 volt difference on the plates and want to play with it.

What is the PI plate voltage supposed to be for the dumble clone? I'm just over 300 volts now down from around 320 stock.

[Structo]

I've heard to keep it between 280 and 300 on the PI. Around 190-200 on V1 & V2.

Don't quote me but I don't think you want both plate voltages to be identical on the PI. If it was desirable the plate resistors would be the same wouldn't they?

Sounds like you are having luck with your D'Lite.
I changed the bass pot from the stock D'Lite, I took off the bass mod.
Went to fire it up and one of the power tubes red plated!
Just some weird oscillation came out of the spkr.