Multiple issues with new build.

[g1]

The reference for the bias circuit is here:
What is Back-Biasing?. Think of it like... all the current from the B+ has to flow back to the centertap of PT. If you fix the ground upstream from that then the centertap is negative with respect to ground.

Thanks. Sorry for the confusion. I've seen the zeners used for lowering B+ and it makes sense it can also provide bias voltage.

Regarding the quote feature I like to use the "Reply with quote" button at the bottom right corner of the post I wish to quote.
One click and the whole post is presented to you in a reply window. Then you can edit the quote to the relevant section of the post that you are discussing (as I did above) and add your comment outside the quote begin & end codes which are shown in square brackets. This method is very fast. It also shows the source of the quote.
Cheers,
Tom

I use the button next to that one, in the lower right corner. If you hover over with mouse, it will say "multi-quote this message". You can select various posts and multiple users this way. Then you hit the reply button and the quotes will show up. Now you can delete the parts you want to omit (I highlight, then right click and select delete). You must leave the codes in the square brackets intact at the begin and end of each quote.
Like Tom mentioned, I think it is good to show the source of the quotes.

[Shadrock2]

If you do that watch out for extra ripple on the bias supply caused by the filter cap charging current pulses through the zeners and 220R. You may have to increase the value of the 100u cap between -40v and ground.

It will probably produce a horrible hum. I got a whole real of those caps.

Regarding the quote feature I like to use the "Reply with quote" button at the bottom right corner of the post I wish to quote.
One click and the whole post is presented to you in a reply window.

It is good to identify the source poster; and I guess its not to much trouble to just delete the sections you don't want to use

I use the button next to that one, in the lower right corner. If you hover over with mouse, it will say "multi-quote this message". You can select various posts and multiple users this way. Then you hit the reply button and the quotes will show up. Now you can delete the parts you want to omit (I highlight, then right click and select delete). You must leave the codes in the square brackets intact at the begin and end of each quote.

Well G1 you have hit upon the most powerful feature yet. Thanx. I did have to turn off my "NoScript" program to get these features. This is not a problem on this forum.


I got some things to try... I'm gonna try reversing the plate leads (which will require splicing extra wire on the shorter lead.

Then I'll try moving the neg. wire on the reservoir cap and report back.
Might take me a day or two to accomplish.
I'll also think about some method of shielding the OPT leads.

[Shadrock2]

So I swapped the plate leads at that fixed 95% of the issues. No motor boating, no whistles. It plays now. Oh yeah!!! does it ever play. Real gain monster. It is plenty loud enough now playing through a 50W Weber Ferromax Vintage series. Never played an amp like this before.

The sound is maybe a little spiky and has lots of overtones; to much maybe. Because it does do a few minor things that are not useful. Like when you play lower notes or especially power chords you can hear tones that are right on the edge of ultrasonic that if you were not listening closely you might call it metal crunch. But if you move the volume (guitar or amp) or tone controls you can hear the ring change frequency. The amp also exhibits a small but noticeable volume reduction when you hit lower notes... especially power chords. I think it is because of supersonic oscillations.

I think if I can just tame it down a little without losing to much harmonic content I will really have something special.