Elimination of electrolytics from amp circuit?

[withnail_jet]

I was wondering what the result would be if one were to replace all electrolytics in a particular circuit with plastic types...? I was thinking about a scratch build using Solen Fast Caps for the high capacitance values where the e-lytics would normally go.

thanks!

[MarkB]

It's been done. Someone posted a pic of his build with Solens in the power supply. They looked like beer cans in the chassis.

Kevin O'Connor uses Solens - go to Londonpower.com and look at his preamp and reverb pics.

[withnail_jet]

It's been done. Someone posted a pic of his build with Solens in the power supply. They looked like beer cans in the chassis.

Kevin O'Connor uses Solens - go to Londonpower.com and look at his preamp and reverb pics.

Yeah, that was where I got the idea. I was curious though, if Solens are used in other places than just filters (i.e., in the tone path), is there a certain characteristic that they will impart on the final sound, as compared to e-lytics?

[MarkB]

From what I've read, I'd expect to hear a difference. The only reason electrolytics are used in the larger values is cost. Whether the improvement would be worth the cost is another matter. In any case, great sounding amps have been built with e-lytics, so I personally wouldn't spend the money.

Try them out, and report back to us.

[mlp-mx6]

Carr amps use all-Solen power supplies also.

[2thick4uni]

Another alternative would be the Polypropelene / oil caps from http://www.angela.com/ they big but not too expensive, 50uf 600v are $18 each

Allan

[MarkB]

Carr amps use all-Solen power supplies also.

There's gut shots of a Carr amp at the Amp Chassis Pic site.

[Bastard Circuits]

Angela SCR (Solen) Non-Polar power supply. The response of the power supply is very fast, but you lose some of the forcefullness in the bass frequencies. Overall, i like the sound. If you want to hear the effect without changing your power supply, change one of your cathode bypass caps with one of the smaller Solens.

[MarkB]

Nice build. It's a really clean look.

[David Root]

It certainly is. Unless I'm much mistaken, you are using electrolytics in the DC filament supply (1) and bias supply (2), the smaller black caps. Also, could you explain why you use double twisted wires from each of the Solen positives, or is that I just can't see the other contact?

[Bastard Circuits]

Thanks. I am using electrolytics in the bias supply, and for the cathode bypass caps (just because I don't have room on the board). The DC heater system isn't actually hooked up, because it was actually quieter with AC. The power supply is standard arrangement. 47uF - Choke - 32uF - 10k - 22uF - 10k - 8 uF. The twisted wires are each connected to their own filter cap, the connections are on the underside of the boards/strips, so they're hidden in that pic.

[andrew]

I have some old PHILCO oil caps at 400v and some at 200v. Is that voltage too low to use in the preamp sections of a SE amp?

[David Root]

400V is fine, I assume you're asking about the 200V caps. If you go back far enough in time, you'll find preamp designs that put 100-130V on the plates e.g. older pre-narrow panel tweeds and Gibsons, so it is possible.
Alternatively just series them and you'll get a 400V composite cap at half whatever the nameplate uF is. Don't forget to parallel them with two series resistors, 220K @ 1W should be OK.

How old are these things? "Philco" makes me think of 50s/60s era. They could leak in service if they're that old, do they look OK?