Sjöström Audio DIY forum

Projects => Power supplies => Topic started by: Khron on June 24, 2007, 07:36:53 PM

Title: Alternate parts for JSR-03/05?
Post by: Khron on June 24, 2007, 07:36:53 PM
How crucial is it for the pass transistor to be a D44H11? Couldn't an MJE15033/34 be used instead? (8A, 250V, 50W)

This far i've almost completed building two JSR-05's, with DIY pcb's, following Mr. Sjostrom's layout, but without a groundplane on the component side. I'm going to use some OPA134's.

Concerning capacitors, i didn't have that many 100u/25-35V at hand, so i used caps that i had (all general-purpose):
- C1 - 47u/63V, Panasonic SU
- C3 - 47u/25V, ROE
- C4 - 47u/50V, Panasonic SU
- C6 - 47u/16V, Elna RE2
- C7 - same
- C11 - same
- C12 - 100u/16V, Nichicon VX

The regulators will put out around 13-14V (to power some active crossovers), and will be powered from something around 35V. Will there be any problems using the parts described?
Title: Re: Alternate parts for JSR-03/05?
Post by: peranders on June 24, 2007, 07:42:24 PM
Choice of pass transistor is dependent of the speed of the opamp you'll use. The transistor you'll suggest is rather fast but will probably not work with AD825, maybe with OPA134.

When it comes to caps, you can use from "general purpose" and up but the output cap should not be "too good", risk for oscillations.
Title: Re: Alternate parts for JSR-03/05?
Post by: Khron on June 24, 2007, 07:44:09 PM
They're all "scavenged" capacitors, and those series are discontinued.

So are the caps' voltage ratings ok? I hope they won't blow up in my face  :-D
Title: Re: Alternate parts for JSR-03/05?
Post by: peranders on June 24, 2007, 07:50:01 PM
The ratings are bit low but not if you'll build for home use.