PBBPaul Posted November 27, 2004 Share Posted November 27, 2004 Any tech folk here have favorite capacitors? I need to do a cap job on my new/old amp project. I've used Sprague Atoms before and the tone was pretty good. Some of the original caps in this amp look like foil and polypropoline type. Can I use electrolytics instead or should I try to replace them exactly? TIA Paul Our new and improved website Today's sample tune: Lonesome One Link to comment Share on other sites More sharing options...
Guitarzan Posted November 28, 2004 Share Posted November 28, 2004 bump http://www.soundclick.com/bands/pagemusic.cfm?bandID=193274 rock it, i will Link to comment Share on other sites More sharing options...
Gabriel E. Posted November 28, 2004 Share Posted November 28, 2004 What's the application? I like Sequa foil-in-oil caps for signal caps. They make the amp sound "smoother" than orange drops. I think with electrolytics, it's more a question of reliability. Atoms don't make the amp sound any better than Illinois caps, they're just sturdier and less noisy. I'm going to use Solen fast caps in the power supply of my amp project. They're pricier than Atoms but because they're not electrolytic, they'll never need to be replaced. "You never can vouch for your own consciousness." - Norman Mailer Link to comment Share on other sites More sharing options...
Blue Strat Posted November 30, 2004 Share Posted November 30, 2004 I've used Vishay 715 and 225 caps. The 715's were .022uF / 600V and the 225's were .047uF / 400V. I couldn't tell a difference. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
PBBPaul Posted November 30, 2004 Author Share Posted November 30, 2004 Thank you for the bump & responses. The application is me turning an old Bogen PA amp into a screamin' Blues machine. The Solens interest me and I like what I've read about the Sequa's as well. I used Orange Drops in my last project and I agree that they sound a bit harsh. Thank you again. Our new and improved website Today's sample tune: Lonesome One Link to comment Share on other sites More sharing options...
Blue Strat Posted November 30, 2004 Share Posted November 30, 2004 Different materials give different tonal variations, or at least that's what I've been told. I've tried both ceramic and poly caps and they both sound great to me. I guess it all depends on the circuit they're used in. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
PBBPaul Posted November 30, 2004 Author Share Posted November 30, 2004 Is it possible for capacitors that aren't completely dried out to be revived at least somewhat? Our new and improved website Today's sample tune: Lonesome One Link to comment Share on other sites More sharing options...
Blue Strat Posted November 30, 2004 Share Posted November 30, 2004 Originally posted by PBBPaul: Is it possible for capacitors that aren't completely dried out to be revived at least somewhat?I've heard that you can bake capacitors in the oven for a while and re-form them, but I've also heard that bit is a myth. The power supply caps in amplifiers are made from a coil of aluminum foil with rubber on one side. I think the idea of baking the caps is to re-melt the rubber so that any voids in the cap fill in. The rubber in the caps gets brittle and cracks over time, which causes a power supply short to ground. POOF!! Not a good situation. BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
PBBPaul Posted November 30, 2004 Author Share Posted November 30, 2004 Originally posted by bluestrat: Originally posted by PBBPaul: Is it possible for capacitors that aren't completely dried out to be revived at least somewhat?I've heard that you can bake capacitors in the oven for a while and re-form them, but I've also heard that bit is a myth. The power supply caps in amplifiers are made from a coil of aluminum foil with rubber on one side. I think the idea of baking the caps is to re-melt the rubber so that any voids in the cap fill in. The rubber in the caps gets brittle and cracks over time, which causes a power supply short to ground. POOF!! Not a good situation.Thanks, The reason I asked is that the amp seems to be getting quieter as I goof around with it. I will still do a cap job but was just curious. I also have an external spring reverb unit that I'd like to incorporate into this project and since it's been sitting in my closet for several years, it has some nasty hum going on. This unit has the caps mounted to a circuit board and they will be difficult to get at. I was hoping that those might reform themselves. I guess I'll just have to solder carefully. Our new and improved website Today's sample tune: Lonesome One Link to comment Share on other sites More sharing options...
Ricochet Posted November 30, 2004 Share Posted November 30, 2004 You can't reform electrolytic caps by baking them (which would be an explosion hazard), but you can often reform them by hooking a resistor of sufficient value to limit the leakage current to a safe value and gradually bringing the voltage up to the rated level. Google for "reforming capacitors" and you'll find a bunch. "A cheerful heart is good medicine." Link to comment Share on other sites More sharing options...
phaeton Posted December 1, 2004 Share Posted December 1, 2004 What a cool thread Dr. Seuss: The Original White Rapper . WWND? Link to comment Share on other sites More sharing options...
Philip OKeefe Posted December 1, 2004 Share Posted December 1, 2004 Once they're dried out or burst / leaking, they're toast - replace them. Bad caps can take out a transformer, and that's not cheap to replace, and in the case of your old Bogen, the replacement tranny may be difficult to find - so don't mess around with "cheap fixes". Electrolytic caps are usually okay... any good brand should be fine - Sprague, Illinois Capacitor, etc. I like (and used) the Sprague Orange Drop polypropylene capacitors in some of my guitar amps that I've rebuilt, with excellent results. When in doubt, find a good tech and have them do the work - filter caps can store a charge for hours - even after the amp is unplugged... so if you don't know what you're doing in there, be safe and get someone else who does to do the work. Link to comment Share on other sites More sharing options...
Ricochet Posted December 2, 2004 Share Posted December 2, 2004 In fact, I made a loud "POP!" and blue flash by shorting out an amp's filter cap more than a week after it had last been powered on. Most amps have resistors to bleed the caps to ground, but that one didn't. "A cheerful heart is good medicine." Link to comment Share on other sites More sharing options...
PBBPaul Posted December 2, 2004 Author Share Posted December 2, 2004 I've worked with caps and a soldering iron quite often and am quite familiar with what they do. I'm just not real familiar with all the differences between types and why one might be better than another. I recapped one of my Fenders with Orange Drops and there was a huge difference in the tone. Not a bad difference, mind you, but a big difference. That's why I was soliciting opinions on peoples' favorites and hoping to get some input as to the tonal differences between different types or even brands of capacitors. I also found it interesting that the amp has become quieter as I've used it more. It's almost silent now with everything at 10 (master, both pres, bass, treble) except for a slight hiss. My reverb unit on the other hand still hums nicely so I'll be ordering caps no matter what. And if I'm doing the reverb, I'm doing the amp too. So that leads me to the next obvious question; I've bought my last couple sets of caps from Antique Electronic Supply and Parts Express. Anybody got a better source? Our new and improved website Today's sample tune: Lonesome One Link to comment Share on other sites More sharing options...
jlh Posted December 30, 2004 Share Posted December 30, 2004 I'm gonna revive this old thread rather than start a new one because it's on the same topic. How do you repair guys deal with the old "can" style capacitors? That is the large metal ones that often stick up along with the tubes on old amps. They generally have two or more caps in the single housing, are riveted to the chassis and have terminals on the bottom. They don't seem to be readily available. Do you just disconnect the terminals and wire in modern caps leaving the can in place for cosmetic reasons? Or do you remove the old cap and just leave a hole? Or something more exotic like actually stuff the new caps into the can and try to make it look like a true restoration? Maybe using radial lead caps instead of axial. Jamie But never fear, you're safe with me... Well maybe. - Les Link to comment Share on other sites More sharing options...
Blue Strat Posted December 31, 2004 Share Posted December 31, 2004 Order your Sprague Atoms (for P.S. filter caps) or orange drops from http://mouser.com or http://digikey.com BlueStrat a.k.a. "El Guapo" ...Better fuzz through science... http://geocities.com/teleman28056/index.html Link to comment Share on other sites More sharing options...
Ricochet Posted December 31, 2004 Share Posted December 31, 2004 Originally posted by jlh: Or something more exotic like actually stuff the new caps into the can and try to make it look like a true restoration? Maybe using radial lead caps instead of axial. JamieThat's what radio restorers do, and what I'd do with a cool old amp that needed recapping (if I couldn't find a suitable "can" cap, which sometimes still can be done.) Google around on radio restoration sites. "A cheerful heart is good medicine." Link to comment Share on other sites More sharing options...
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