Bias circuit electrolytics?

New here? Need help? Don't know where to post? Post here.

Moderator: VelvetGeorge

Post Reply
revolver1
Senior Member
Posts: 511
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

Bias circuit electrolytics?

Post by revolver1 » Wed Jun 28, 2017 6:41 am

I 've been staking out some boards and last night I layed out the components to have a look. I noticed the body of the electrolytic caps are quite close to the turrets either side and the cans will practically be touching one another.
Is this cause for concern?

danman
Senior Member
Posts: 1099
Joined: Tue Sep 10, 2013 9:09 pm
Just the numbers in order: 13492

Re: Bias circuit electrolytics?

Post by danman » Wed Jun 28, 2017 8:15 pm

No problem with that. There is no heat issue to worry about with those two caps so letting them touch will be fine. If you have a little space on either side, you can bend the leads slightly to push one of the caps to the left or the right just a bit.

revolver1
Senior Member
Posts: 511
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

Re: Bias circuit electrolytics?

Post by revolver1 » Thu Jun 29, 2017 1:49 am

Cheers danman.

I've been trying to get a link from my posts to photo bucket. I'd like to post pics as these builds really start to progress but I'm not all that computer savy. Do you know how it's done?

Roe
Senior Member
Posts: 5054
Joined: Thu Apr 13, 2006 1:36 pm
Just the numbers in order: 7
Location: Drontheim. Norwegen
Contact:

Re: Bias circuit electrolytics?

Post by Roe » Thu Jun 29, 2017 7:10 am

these caps affect the sound. Try BC 10uf 160v, at least for the cap closest to the grids
http://www.myspace.com/20bonesband" onclick="window.open(this.href);return false;
http://www.myspace.com/prostitutes" onclick="window.open(this.href);return false;
Super 100 amps: 1202-119 & 1202-84
JTM45 RS OT JTM50 JMP50 1959/2203/34/39

danman
Senior Member
Posts: 1099
Joined: Tue Sep 10, 2013 9:09 pm
Just the numbers in order: 13492

Re: Bias circuit electrolytics?

Post by danman » Thu Jun 29, 2017 8:27 pm

I'm not very computer savvy either so I've never figured out how to do it...lol!

revolver1
Senior Member
Posts: 511
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

Re: Bias circuit electrolytics?

Post by revolver1 » Fri Jun 30, 2017 2:01 am

:lol: :lol: :lol:

Hey Roe, I had no idea these caps had an impact on the sound. So is it a heat thing coming off the grids???

I'm going to have a go at staking another bord this weekend since I made a few minor errors ie a turret where it shouldn't be.... I was a bit unsure but I have the option of slipping a bit more space between the grids and the diodes on the either side of the bias circuit if that's a good idea?

I used the BC 10uf 160v on my last build a while ago and that amp sounded great, this time I've got some NOS Tesla 10uf 160v. They look the part but I'm still undecided wether I should leave them out because of there age and just go with some BC?
Of course I would post pics but the technologies ilude me....

I have an esr metre but I'm not sure how much use it is on small caps?

Roe
Senior Member
Posts: 5054
Joined: Thu Apr 13, 2006 1:36 pm
Just the numbers in order: 7
Location: Drontheim. Norwegen
Contact:

Re: Bias circuit electrolytics?

Post by Roe » Fri Jun 30, 2017 2:58 am

the grids and screens grids of the power tubes are very sensitive and small changes can matter. Screens filtering matter as do the bias filtering
http://www.myspace.com/20bonesband" onclick="window.open(this.href);return false;
http://www.myspace.com/prostitutes" onclick="window.open(this.href);return false;
Super 100 amps: 1202-119 & 1202-84
JTM45 RS OT JTM50 JMP50 1959/2203/34/39

Post Reply