Power supply, Filter Caps
- Thread starter BillyO
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Re: Power supply, Filter Caps
I did find one that will fit in my Fender Prosonic, A Solen "fast" cap 4.7uF 630 volt. I just don't want to do something that will blow up my amp. The only Electrolytic I can find is cheep Chinese junk in 4.7uF.
I did find one that will fit in my Fender Prosonic, A Solen "fast" cap 4.7uF 630 volt. I just don't want to do something that will blow up my amp. The only Electrolytic I can find is cheep Chinese junk in 4.7uF.
Re: Power supply, Filter Caps
Electrolytics are probably all made in Asia, if not China. Unless you find a NOS Black Gate or some other discontinued "audiophile approved", overpriced electrolytic, just about all of the 4.7uf caps are going to be cheap (as in, inexpensive). That doesn't make them all junk. Panasonic surely has some in the value you need. Or, go with one of these Elna caps ... it's probably audiophile approved ... http://www.partsconnexion.com/capacitor_ele_elna_roa.html
Electrolytics are probably all made in Asia, if not China. Unless you find a NOS Black Gate or some other discontinued "audiophile approved", overpriced electrolytic, just about all of the 4.7uf caps are going to be cheap (as in, inexpensive). That doesn't make them all junk. Panasonic surely has some in the value you need. Or, go with one of these Elna caps ... it's probably audiophile approved ... http://www.partsconnexion.com/capacitor_ele_elna_roa.html
crusty philtrum
Vintageologist
Re: Power supply, Filter Caps
Are you certain 4.7 uF is the correct value ? I have just had a look at a couple of Prosonic schematics, but they dont enlarge well. To the best of my scrutiny, three of the main filter caps appear to be 47uF/ 500V electrolytics, and I can't see any 4.7uF caps anywhere. (47uF is a normal sort of value for these positions, 4.7uF would normally be considered too small).
If you have mistaken the 47uFs for 4.7uFs, forget about using non-electro replacements ... IF you can get 47uFs at 500+ DC Volts, they will be ridiculously large and ridiculously expensive.
Are you certain 4.7 uF is the correct value ? I have just had a look at a couple of Prosonic schematics, but they dont enlarge well. To the best of my scrutiny, three of the main filter caps appear to be 47uF/ 500V electrolytics, and I can't see any 4.7uF caps anywhere. (47uF is a normal sort of value for these positions, 4.7uF would normally be considered too small).
If you have mistaken the 47uFs for 4.7uFs, forget about using non-electro replacements ... IF you can get 47uFs at 500+ DC Volts, they will be ridiculously large and ridiculously expensive.
Re: Power supply, Filter Caps
I have replaced all of the electrolytic caps in this amp with Sprague Atom caps (not cheep) The 4.7uF cap in question is the only one I can't find in a good quality electrolytic. Also this cap needs to be at least a 500 volt axial type. Hence my original question is do they have to be electrolytic?
I have replaced all of the electrolytic caps in this amp with Sprague Atom caps (not cheep) The 4.7uF cap in question is the only one I can't find in a good quality electrolytic. Also this cap needs to be at least a 500 volt axial type. Hence my original question is do they have to be electrolytic?
Re: Power supply, Filter Caps
There are two 100uF 350v caps in series, one 4.7uF 500v and two 47uF 500v. I have a clear schematic and the amp that I'm looking at and that's what's in it. I almost put a 47uF cap in there until I removed the 4.7 and looked up close, I thought it odd too but that's what's there.
There are two 100uF 350v caps in series, one 4.7uF 500v and two 47uF 500v. I have a clear schematic and the amp that I'm looking at and that's what's in it. I almost put a 47uF cap in there until I removed the 4.7 and looked up close, I thought it odd too but that's what's there.
crusty philtrum
Vintageologist
Re: Power supply, Filter Caps
Nope, they don't have to be electrolytic. If we could be certain exactly whereabouts in the circuit this cap is located, it could be possible to suggest using a different (perhaps more easily available) capacitance value. Do you have a good quality schematic you can post ? The only ones i can find are illegible in terms of component values.
Then of course there's things you could do by using more than one cap in series or parallel to attain the required value and voltage ratings.
Nope, they don't have to be electrolytic. If we could be certain exactly whereabouts in the circuit this cap is located, it could be possible to suggest using a different (perhaps more easily available) capacitance value. Do you have a good quality schematic you can post ? The only ones i can find are illegible in terms of component values.
Then of course there's things you could do by using more than one cap in series or parallel to attain the required value and voltage ratings.
crusty philtrum
Vintageologist
Re: Power supply, Filter Caps
Is the 4.7uF cap closest to, or furthest from, the series pair of 100u/350V electros on the schematic ?
Can you post the schematic you have ? (or a link to where it can be found)
Is the 4.7uF cap closest to, or furthest from, the series pair of 100u/350V electros on the schematic ?
Can you post the schematic you have ? (or a link to where it can be found)
Re: Power supply, Filter Caps
All I have is a PDF file, Don't see how to upload it here. The cap is closest to the series caps and is right after the choke and goes into the center of the power tubes through a 1 watt 470 ohm resistor. I don't know witch is the grid, plate etc. in the tubes
All I have is a PDF file, Don't see how to upload it here. The cap is closest to the series caps and is right after the choke and goes into the center of the power tubes through a 1 watt 470 ohm resistor. I don't know witch is the grid, plate etc. in the tubes
crusty philtrum
Vintageologist
Re: Power supply, Filter Caps
In that position, my thoughts would be that a misprint or a speck on the schematic has made what should be 47uF appear to be 4.7, and that someone has replaced the original 47uF with a 4.7 after looking at the schematic.
It seems you have removed a 4.7 from that position .... does it look original, or like a replacement ?
Either way, for a cap in that position, i'd bet money that it's supposed to be 47uF, and I would replace it with one.
In that position, my thoughts would be that a misprint or a speck on the schematic has made what should be 47uF appear to be 4.7, and that someone has replaced the original 47uF with a 4.7 after looking at the schematic.
It seems you have removed a 4.7 from that position .... does it look original, or like a replacement ?
Either way, for a cap in that position, i'd bet money that it's supposed to be 47uF, and I would replace it with one.
Re: Power supply, Filter Caps
http://www.studiosoundelectronics.com/schematics/prosonic.pdf That cap does look original, Also I have two separate schematics, One for the head version and one for the combo prosonic, Both show a 4.7 there
http://www.studiosoundelectronics.com/schematics/prosonic.pdf That cap does look original, Also I have two separate schematics, One for the head version and one for the combo prosonic, Both show a 4.7 there
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Re: Power supply, Filter Caps
I'm guessing C203 is the cap in question (GZ34 rectifier on the schematic).
http://ampwares.com/schematics/prosonic.pdf
I'm guessing C203 is the cap in question (GZ34 rectifier on the schematic).
http://ampwares.com/schematics/prosonic.pdf
crusty philtrum
Vintageologist
Re: Power supply, Filter Caps
See what i wrote in post #12. Indeed i think it is a mistake on the available schematics, and that it should be 47uF. I would have no hesitation in installing a 47uF/500V cap in that position. Never have i seen a filter cap for the screen stage as low as 4.7uF.
See what i wrote in post #12. Indeed i think it is a mistake on the available schematics, and that it should be 47uF. I would have no hesitation in installing a 47uF/500V cap in that position. Never have i seen a filter cap for the screen stage as low as 4.7uF.
Re: Power supply, Filter Caps
Looks like you may be right, What's weird is it is a 4.7 that I removed from there. The reason I started looking for issues is the amp will get ungodly loud but has almost no bass response, tone controls don't do hardly anything. Could too low of value cap there be that problem?
crusty philtrum
Vintageologist
Re: Power supply, Filter Caps
Yes.
If this was my amp, and now with the information we have, I'd definitely install a 47uF cap in that position.
It is not totally unknown for schematics to have errors in component values, but it is strange that it actually had the 4.7uF value installed. Maybe a previous owner detected the 'mismatch' between schematic and actual component, and decided to 'correct' it.
Yup, just install a 47 and report back with your findings.
Yes.
If this was my amp, and now with the information we have, I'd definitely install a 47uF cap in that position.
It is not totally unknown for schematics to have errors in component values, but it is strange that it actually had the 4.7uF value installed. Maybe a previous owner detected the 'mismatch' between schematic and actual component, and decided to 'correct' it.
Yup, just install a 47 and report back with your findings.
Re: Power supply, Filter Caps
Ordering it today, in the last hour I have looked at at least 50 fender schematics none of them had filter caps below 16uF, and that was a 6 watt amp. I will report back when I install the new proper value cap. Thanks very much guys!
Ordering it today, in the last hour I have looked at at least 50 fender schematics none of them had filter caps below 16uF, and that was a 6 watt amp. I will report back when I install the new proper value cap. Thanks very much guys!
