Amp project

[Rockn]

Continuing on from the 5v winding in a previous post I am now looking at the electrolytic caps in the power supply filter section. I am building a Kalamazoo M1 and it calls for a 20-10-10 400v cap in the schematic. The chassis and PT are from an old Roberts tape player and all of the old electrolytics were rated at 300v. I have a 40-20-20 350v cap that I am wondering if it would work. The B+ is around 260v so would 350v be enough to allow for surge on the circuit?

Would be easy enough to go get three seperate cans, but I have this one and was hoping it would be OK. Is there a spec for the rectifier tube that limits what the capacitance for the first cap should be? IN this case the rectifier is a 6X4 tube.

Thanks

[Gtr_tech]

I wouldn't push it any further than the 20u. Datasheet doesn't give a max value for a cap input filter but in the typical operation chart they show a 10u. 40 would be too much I'm guessing....a cap looks like a short to the rectifier before it charges. Draw too much current and the rectifier will zorch.

[Rockn]

Any idea where I could source a 20-10-10 450v cap? I have looked at quite a few sources and the closest I have found was one with an additional 10uf at the end. Not a big deal if I have to get separate caps, but the chassis is rather cramped.

Thanks

[hasserl]

Originally Posted by Rockn

Any idea where I could source a 20-10-10 450v cap? I have looked at quite a few sources and the closest I have found was one with an additional 10uf at the end. Not a big deal if I have to get separate caps, but the chassis is rather cramped.

Thanks

Use the 20-10-10-10 cap and just leave one of the 10's unused.

Or open up the old can and remove the old caps and stuff new caps inside of it.