Encore style build needs trouble shooting

[angelodp]

I have built this Encore style amp from donor parts. I went through the PT and OT carefully and derived their windings and voltage. They both fit the bill. I scored a typical choke and reverb transformer for the build. I went through the build in stages and all was checking out. Voltage on the B+ side were right in line and the OT specced out nicely. I get good voltage reading throughout but no sound. The amp does not pass any signal to the output. I don't have a scope so I am looking for any help to trouble shoot this build. I suspect its something quite simple as i checked and rechecked all my component values and layout connections. Plate and cathode voltage are as expected.

I used the layout graphic below. I have yet to include the bias jacks and I moved the bias pot to the back wall.

[IMG446]http://i260.photobucket.com/albums/ii9/angelodp1/Encore-buildpic-2_zpsd76b75dd.jpg[/img]


[IMG425]http://i260.photobucket.com/albums/ii9/angelodp1/7551183f-5ed0-4290-b5e5-d046cc7b5910_zps6ad6105f.jpg[/img]

[M Fowler]

Angelo is the input jack grounded?

[angelodp]

No its ground via contact with the chassis as in the original Encore layout.

[M Fowler]

I would make sure the speaker jacks are wired right.

You could do the pop test starting from output working your way through input.

[angelodp]

I used the speaker setup that Martin drew up. It has the 7ohm 5w r across the two switches on the 12A jacks. Its the no-load shorting protection setup. I get nothing at the output, how would the pop test work.

[M Fowler]

Is pin 8 on both power tube sockets going to ground?

The amp must be on, connected to a speaker or dummy load, then ether use pop test by touching a test prob to these points or using an oscilloscope with a test tone in the input, usually about 1000 hz. Always start from the back and work your way to the front.

[angelodp]

No they are open. I did not have the bias jacks… do I need to ground those pins.

[M Fowler]

No they are open. I did not have the bias jacks… do I need to ground those pins.

Yes ground pin 8 for 6L6 or 6V6.

Ground both pins 1-8 for EL34 use.

[angelodp]

I went without the selector and direct to the jacks with 4ohm 8ohm. I believe its according to drawing from MM.

[IMG768]http://i260.photobucket.com/albums/ii9/angelodp1/Encorejacks_zpsd345d429.jpg[/img]

[angelodp]

Ok so both power tube sockets get grounded… shall I leave out the 1ohm resistors for now until I get the bias jacks?

[M Fowler]

Ok so both power tube sockets get grounded… shall I leave out the 1ohm resistors for now until I get the bias jacks?

Yes leave them out until your ready for the test jacks.

[angelodp]

Ok that got sound but its squealed pretty bad, shut it down… I suppose I have the OT wires screwed up ?

[M Fowler]

Not sure I have that drawing from MM.

[M Fowler]

Ok that got sound but its squealed pretty bad, shut it down… I suppose I have the OT wires screwed up ?

I would say that is correct swap them around and fire that bitch up and watch bias.

[angelodp]

Ok, I did get sound, but I could no crank it as it started to chirp when I raised the master. One of the Power tubes looked like it was gonna go cherry as well so i shut it down. I don't think I have sufficient bias voltage. I am only reading -26v as I have it set up. Perhaps I need to bring that 100k further down to bring up the bias voltage…