#102 Started. Checking in

[Deric]

Thanks guys! The amp fired right up when I changed the relay wiring. It is working perfectly. It already sounds pretty good. I'll bias it and fiddle around with some of the trim pots.

thanks to everyone for their help!!

oh, and this has to be the quietest amp i have!! and also the loudest

Congrats! Thanks for sharing the build.

[Structo]

Yeah, I believe that is my drawing for the relay.
I made those after getting the JBorders relay boards because they differ from the Dumble layout.

Here is the complete drawing showing the comparison of the two styles.

Martin's drawing just swaps sides of the relay so it is essentially the same.

[talbany]

Taylor

Glad you got it working Enjoy!!

T

[amplifiednation]

Taylor

Glad you got it working Enjoy!!

T

Tony thanks for the awesome layout. Next I'm going second gen after your good reviews. I already have some killer old iron for it!

[amplifiednation]

Got about 20hrs of burn on the amp. The bias drifted a bit. Have it biased at 13w/tube. Did 4hrs on then 4hrs off for about 40hrs with some cheapo Chinese tubes. Even the hiss seemed to mellow out. Used a 4ohm car speaker as a load. I think it was a good move.

Voltages
V1a/b-206/213
V2a/b-200/206
Pi-289/287 still playing with the trimmer. I have a nice amperex that seems matched

6l6- plates 445

Should I try to get v1 down a bit?or leave it as is for awhile?

[ChrisM]

Bring V1 down

Also your bias is way low, 13W a tube. That's around 45% dissipation. You want more 60-70%.

[amplifiednation]

Bring V1 down

Also your bias is way low, 13W a tube. That's around 45% dissipation. You want more 60-70%.

I must have read some incorrect info about the 6L6. Rebiased to 19.5 at 65% . The amp is still singing

I need to adjust b5 dropping resistor?

[ChrisM]

Bring V1 down

Also your bias is way low, 13W a tube. That's around 45% dissipation. You want more 60-70%.

I must have read some incorrect info about the 6L6. Rebiased to 19.5 at 65% . The amp is still singing

I need to adjust b5 dropping resistor?

6L6GC are rated at 30W max plate dissipation, so that sounds better.

Sounds like the right resistor to tweak. Also try swapping some tubes in there.

[amplifiednation]

Cool. I will try to figure out the right value to put in there. What are the effects of having V1 below V2? -10V is the goal??

[ToneMerc]

I must have read some incorrect info about the 6L6. Rebiased to 19.5 at 65% . The amp is still singing

I need to adjust b5 dropping resistor?

What are the preamp voltages now?

[amplifiednation]

I must have read some incorrect info about the 6L6. Rebiased to 19.5 at 65% . The amp is still singing

I need to adjust b5 dropping resistor?

What are the preamp voltages now?

Voltages V1a/b-206/213
V2a/b-200/206
pi-289/287 still playing with the trimmer. I have a nice amperex that seems matched

6l6- plates 445

[ToneMerc]

I must have read some incorrect info about the 6L6. Rebiased to 19.5 at 65% . The amp is still singing

I need to adjust b5 dropping resistor?

What are the preamp voltages now?

Voltages V1a/b-206/213
V2a/b-200/206
pi-289/287 still playing with the trimmer. I have a nice amperex that seems matched

6l6- plates 445

Taylor, these appear to be the same voltages that you posted when the amp was at 45%. The voltages shouldn't be exactly the same after rebiasing from 45 to 65%.

TM

[amplifiednation]

What are the preamp voltages now?

Voltages V1a/b-206/213
V2a/b-200/206
pi-289/287 still playing with the trimmer. I have a nice amperex that seems matched

6l6- plates 445

Taylor, these appear to be the same voltages that you posted when the amp was at 45%. The voltages shouldn't be exactly the same after rebiasing from 45 to 65%.

TM

TM sorry here are current:

V1a/b- 208.4/215.7
V2a/b-203/208.2
PI 292.9/291.2

Thoughts?

[ToneMerc]

Voltages V1a/b-206/213
V2a/b-200/206
pi-289/287 still playing with the trimmer. I have a nice amperex that seems matched

6l6- plates 445

Taylor, these appear to be the same voltages that you posted when the amp was at 45%. The voltages shouldn't be exactly the same after rebiasing from 45 to 65%.

TM

TM sorry here are current:

V1a/b- 208.4/215.7
V2a/b-203/208.2
PI 292.9/291.2

Thoughts?

The FET circuit is definitely connected to B5 right? Have you tried a different tube in V1? You could sub in a 4.7K in place of the 2.2K.

TM

[amplifiednation]

Yes I have tried a couple different tubes. The FET is connected to B5. I wasn't thinking there would be current draw from there. I don't have the board wired right, I may have mixed up two resistors, which might explain the voltages at the tube. The FET input is not working right, it makes sound but sounds like its starving for dc. I will take a better look at the source resistor. I'm gonna get that working right before messing with the dropping string