Master volume and Presence

[Nikk]

Hey guys thanks for the advise I will now go away and try to digest all of that .Seriously thanks for your time when you say the preamp groundbus is grounded at 2 points are you looking at the connection by the PT end as this is not grounded or is it somewhere else i am not seeing .

[talbany]

The layouts I did are just as Dumble did it including lead dress, ( where to put tag strips) ground points. It's all here I would go over the amp and double check all your grounds throughout each section of the amp (power supply,bias,PI, preamp,relays) lead dress and make sure everything that needs to be shielded and separated is and cross it using the layout and you should be fine.
BTW. If you (or anyone) deviates even slightly from what is on the layout you increase your chances of oscillations or simply have a crappy sounding amp..ESPECIALLY! those first time builders.

This was the main reason why I did a layout.
https://ampgarage.com/forum/download/fi ... &mode=view
Tony

[xtian]

Hey guys thanks for the advise I will now go away and try to digest all of that .Seriously thanks for your time when you say the preamp groundbus is grounded at 2 points are you looking at the connection by the PT end as this is not grounded or is it somewhere else i am not seeing .

Thanks for the new photo--now I can see that your buss is isolated from the chassis at the master volume end--that's cool. What's the black wire connected to the buss near that end?

[talbany]

Hey guys thanks for the advise I will now go away and try to digest all of that .Seriously thanks for your time when you say the preamp groundbus is grounded at 2 points are you looking at the connection by the PT end as this is not grounded or is it somewhere else i am not seeing .

In the picture it looks like you have 2 wires tied to the isolated tag strip that holds that end of the buss bar. I assume the black wire is for V1/V2 filters? There also looks to be a yellow wire that goes to the power transformer. Preamp input bus should mainly carry V1 V2 cathodes,filters,input jack and volume/tone pots,otherwise you may get some noise.

https://www.aikenamps.com/index.php/grounding

Tony

[Nikk]

Black wire at end of bus bar near Transformer is the common ground for the power supply B+ etc I think been a while now . I have had a change about and put all the PT grounds to the lug where it looked like it was a ground this is not connected to the bus bar .As far as hum it is fairly good now not silent but not in any way more or less than a lot of amps the oscillation is still there but better and different now the master goes up and suddenly the volume jumps at specific points of the dial . I will get there I am grateful to all of you for your advise sorry if I dont get back I struggle with the forums I can never workout how to do stuff bit like the amps . It takes me weeks to do what most of you do in minutes as everything is a learning curve . I will get there i have done it before and will again just a matter of time or until i blow it up .

Nikk