View Full Version : High-quality capacitors needed for valve amp PSU
Hi guys,
I'm due to re-cap my Copper amp soon, and am looking for recommendations for the BEST caps available. I normally prefer to use polypropylenes, but since there are 1970s Plessey electrolytics in there at the moment (which the amp has been voiced with), I'm tempted to replace like with (as near as) like, if you see what I mean... :)
The values I need are 32uF 500v (or higher) x 4. I was looking at BHC Aerovox, but can't seem to find the right values. Price is irrelevant - the sky's the limit, if it's worth it!
Any help or advice would be appreciated. When making suggestions, however, please include a link to sites where whatever caps you're recommending are in stock and available to buy now.
Many thanks! :cool:
Marco.
What does the designer of the Copper amp recommend?
In general, I'm suspicious of 'designer' audiophile components and prefer those of military and aerospace quality.
Regards
Ali Tait
28-05-2011, 14:57
You may prefer the sound of polys Marco. Won't know till you try though.
StanleyB
28-05-2011, 15:01
In general, I'm suspicious of 'designer' audiophile components and prefer those of military and aerospace quality.
I'll 2nd that. The Russian made ones are of particular outstanding sonic quality.
Mind you, 32uF/500V would be extremely hard to find...
Rare Bird
28-05-2011, 17:10
Are they single or double caps Marco as in 32+32uF?
I believe that they're doubles, dude - any suggestions? :)
Barry, Anthony would like to use those from BHC Aerovox (which are military and aerospace quality), but it's finding the right values!
Stan,
Mind you, 32uF/500V would be extremely hard to find...
That appears to be the case. If you don't mind me asking - why? I didn't think the Copper amp had particularly 'special' requirements...
If we can't find any suitable electrolytics, then we're thinking of using these Mundorf 'Tubecaps', from Hi-Fi Collective:
http://www.hificollective.co.uk/components/mcap_tubecap.html
...which Nick has just fitted in my Croft preamp, as smoothing caps (and were excellent!) 8 x 20uF would do the job (as they're singles). They certainly didn't harm the Croft. So, Ali, you might be right. I'd be tempted though to use some military grade electrolytics, such as the Russian ones Stan mentioned, if I could find some that were suitable.
Incidentally, what's the view on using NOS? I suppose it would be dodgy, as electrolytic capacitors deteriorate with age, used or not?
All advice appreciated, but links to actual caps available to buy, would be best! :cool:
Marco.
Rare Bird
28-05-2011, 17:49
Elna Cerefines were available in double if you manage to get an NOS somewhere. They did 32uF+ 32uF as I built a single ednded 2A3 years ago with em, superb...you'll have to measure the diameter of you originals. Are you sure the H.T requires 500V?
Yep, 100% on that one, as Anthony was very specific about that! Is 500V particularly high, then?
I presume that the Elna Cerefines are now discontinued?
Marco.
Rare Bird
28-05-2011, 17:59
Suppose not i was expecting about 350V! Anyway yes they are NOS , i think Mundorf do a MLytic HV at 32+32/500..check diameter again
What's your thoughts about using NOS caps, though - wouldn't it be risky expecting very old caps still to be performing optimally? :)
I know of the Mundorf MLytics, but TBH, if it came to that I'd probably just go for the Tubecaps I mentioned earlier, as I suspect they'd be better.
Marco.
Rare Bird
28-05-2011, 18:09
Cerafines wernt like standard Electrolytics they used ceramic particles, i doubt they will break down with age..I pesonally would buy the Mundorf nowadays..
Ah, I see what you're saying about the Elnas...
Dunno why BHC don't seem to do the right values, though. Farnell has 100s of them (some rated at 500V), but none of the right capacitance :doh:
Perhaps if I emailed them, they'd make some up as a special order? ICW (Clarity cap) may also do that....
Marco.
I would avoid NOS electrolytics (unless I am selling my small stash of BG WKZ's :-)). Does the value have to be that exact Marco? I think your amp is SS rectifier, so larger valves should do no harm, and could be a benefit. 500v electrolytics are far less common, 450v is the normal voltage limit, but 500v do exist. Though I use lower voltage ones in series for higher voltage use. You could also look at Motor run film caps.
anthonyTD
28-05-2011, 21:00
hi Nick,
marco's amp uses a pair of GZ34 rectifiers so the first resevoir cap is limited to 50uf, the caps i used were original plessey 16 +16 and i doubled up the first in line to give 32uf, the voltage rating of 500v is to make sure they are absolutely safe with the surge voltage from standby mode.
obviously the caps used elsewhere in the circuit could be 450v working.
Anthony,TD...
Ahh, sorry, I stand corrected. So, yes, you have the limit on the first cap after the rectifier,
Cheers, chaps. Anthony, you have email! :)
After some digging, and much help from Andre (and Nick), the front runners are now custom options from Ansar, such as mentioned here:
http://www.suppression-devices.com/ansar/spx-audio-capacitors.html
I like the idea of being able to specify solid silver lead-out wires, etc... And judging by the description, they seem like superb quality:
http://www.suppression-devices.com/ansar/audio-capacitorstechnical.html#Choice
Also, there is the option of going for custom ones from ICW in Wrexham. They of course make the superb Clarity Caps. Their PCS range, looks ideal for Copper amp duties:
http://www.icwltd.co.uk/power4/image.htm
Now, I use the MRs in the crossovers for my Tannoys, which are superb, so if the PCS range is as good, then it would be a VERY valid option indeed...
Decisions, decisions! :doh: :eyebrows:
I'll have a chat with Anthony about this, but what do you think would be the best move, Nick? Bear in mind that I would like the absolute best caps possible (sonically speaking), as this job will be a case of 'do it once and do it right with no compromise', if you see what I mean.
Marco.
Any of those would be good. I would chose what fits the case best.
Good point, and very relevant! However, presuming that both types will fit, if it were you doing the job, which ones would you be inclined to go for? :)
Perhaps based on the spec/descriptions of the caps mentioned on the respective websites and/or the reputation for quality of both companies.... (or anything else you consider important).
At the moment I'm leaning towards ICW, simply because of their level of expertise in the professional industry and amount of resources available for R&D....
Marco.
StanleyB
28-05-2011, 22:16
Capacitors are made out of a range of materials for a reason. Manufacturer reputation counts for nothing if the end user uses the wrong type of capacitor material for a critical job.
Also keep in mind the tolerances of the cap. A 32uF would have to have a tolerance of less than 5% before it is guaranteed to be any different to a 33uF cap.
I've heard various flavours of WAD 300b amps, one was full of polypropylene caps in the psu, it sounded very different to the others containing lytics, brighter with lighter bass, the brightness was a little much for me with busy music in the system I heard it in . Of course it all comes down to system and taste. They may also work great in the copper amp , just thought its worth mentioning though :)
I've known high capacitance lower voltage NOS caps to work ok after being properly formed, not sure about the higher voltage types though, probably best to avoid if unsure.
Never tried these http://www.jj-electronic.com/pdf/TC_TE.pdf
Hi guys,
Good points, and noted. The Copper amp is essentially voiced to be a wide-open window. It is extremely revealing and detailed, truthful, yet unfailingly musical sounding.
Therefore, I'm after capacitors simply which impede the signal the least and allow the amp to show exactly what is there, in terms of what the circuit is doing, and also what is actually on recordings.
It's also how my system is voiced to present music, and so its constituent components ably facilitate the intended effect. Therefore, I'm not looking for caps which add euphony, and thus act as tone controls. Ultimate resolution (least sonic signature), and thus highest accuracy possible, is the goal.
Leo, where are the JJs available to buy? They're an interesting possibility, although I think that I'm fairly set on using either the Ansars or ICWs :)
Marco.
Well, my only thought would be the ICW range you linked to are designed for DC filtering in power supplies. The Ansar, are aimed I guess at signal coupling use. So the ICW seem to be made for the use you want to put them to.
I'm inclined to agree... Now all I need to do is get the ball rolling! :)
Marco.
I'm sure the polypropylenes in the WAD amp I heard was Ansars, maybe the ICW's would be better? dunno tbh. The only way to know these things for sure is try them, I'd keep the old caps just incase you want to revert back ;)
I've never tried the JJ's so can't comment on them, was one of the few choices at 500v I could find http://www.partsconnexion.com/capacitor_ele_jjcap.html
The usual places for components below ,maybe Mark at Audiocom could recommend something?
Mundorf http://www.partsconnexion.com/capacitor_ele_mundorf_hv.html
http://www.partsconnexion.com/index.html
http://www.percyaudio.com/
http://www.hificollective.co.uk/
Hi Leo,
Thanks for the info. I hadn't heard of Percy Audio before, so I've bookmarked them for future reference. The more places you know where to get parts from, the better.
The existing caps are over 35 years old, mate, so they won't be going back in! ;)
I think that I've pretty much made my mind up now on getting the ICWs, so it's just a case of organising it :)
Marco.
anthonyTD
29-05-2011, 09:55
hi all,
thanks for all your input, we all have our individual experiences and prefrences with diffrent components, especialy caps, of course the ultimate prefrence is "no cap" but unfortunetly we dont live in a perfect world!
anyway, as Marco has already explained, the caps i used originaly in all the first copper amps were plessey, they were new old stock, but before using them i carefully re-formed every one, checking their current draw and leakage throughout the process.
The issues i am worried about is total sonic character change when using a diffrent dielectric type, ie polyprops, etc.
That's why i agreed it was a good idea to get some feedback from you guys on what marco should eventualy settle on and not just go on my recomendation.
its up to him now!:)
Anthony,TD...
Indeed, but I also require your erudite input, oh great one. You have email! :)
Marco.
One option in this position to get a feel for polyprop would be a 1uF bypass cap across the last caps in the power supply.
Good suggestion, Nick... Might try that :)
My view though is kind of that if high-quality polyproplene caps are essentially more accurate (i.e impede the signal the least), then when used in an amp like the Copper amp, which has no overt sonic signature, it shouldn't be a bad thing - in fact it's more likely to be beneficial.
This exercise isn't about tailoring the sound to suit a certain sonic signature, such as adding sparkle and vitality to a warm sounding amp, or vice versa. It's about allowing the circuit to reveal more of its true potential.
Marco.
Good suggestion, Nick... Might try that :)
My view though is kind of that if high-quality polyproplene caps are essentially more accurate (i.e impede the signal the least), then when used in an amp like the Copper amp, which has no overt sonic signature, it shouldn't be a bad thing.
Marco.
No, I agree, logic would indicate that, but that synergy thing is still there. if the Amp has been carefully voiced by Anthony with the signature of the power supply caps in mind the final result might be less than optimum.
Yup, I know what you mean, but its a calculated risk I'm willing to take.
Also, replacing heavily used electrolytic caps that are over 35 years old, some of which are starting to bulge, with pretty much anything that's newer, shouldn't do too much harm! ;)
Marco.
anthonyTD
29-05-2011, 11:09
One option in this position to get a feel for polyprop would be a 1uF bypass cap across the last caps in the power supply.
hi Nick,
we are on the same wavelength there!
All power supply caps are already bipassed with polyprops.:)
one of the main issues apart from the obvious sonics is the physical size of most types of polyprops sugested so far.
Anthony,TD...
Oh right, yep, I'd forgotten about that! Well, in that case, the 'transition' from electros to polys shouldn't be too painful... ;)
Marco.
My tiny take on this is that if Clarity Cap are in Wrexham, I'd regard it as a no-brainer to be honest. Same for me and Sowter transformers, who are up the road in Ipswich...
all my amps use maplins motor run caps or icw caps in the power supply
i can not tell the difference, they need and hour or two to break in before they start to sound ok
but there's lots of things i stuggle to hear !!! and my amps run at slightly less volts
there are lots of other things that contribute to getting the power supply smooth... with the least interference to the flow
which i'm sure anthony has taken into account
anthonyTD
29-05-2011, 15:24
all my amps use maplins motor run caps or icw caps in the power supply
i can not tell the difference, they need and hour or two to break in before they start to sound ok
but there's lots of things i stuggle to hear !!! and my amps run at slightly less volts
there are lots of other things that contribute to getting the power supply smooth... with the least interference to the flow
which i'm sure anthony has taken into account
hi Steve,
thanks for your input, the main power supply in marco's amp is pretty clean and stable being of the cap, choke, cap type, i agree about the motor run caps they are very good.
Anthony,TD...
Hi Steve,
Thanks for your input. Interesting that you (sometimes) use ICW caps in your power supplies. That's good enough for me! :)
And like Dave says, they're in Wrexham, 10 mins from my house. It'll all depend though if valleee-boy can handle his precious amp design having some North Walian DNA!! :lol:
;)
Marco.
Rare Bird
29-05-2011, 16:06
hi Steve,
thanks for your input, the main power supply in marco's amp is pretty clean and stable being of the cap, choke, cap type, i agree about the motor run caps they are very good.
Anthony,TD...
Right so you basically have 32uF each side of the choke (of with you are utilising 16uF+16uF caps to create the required capacitance or 32uF )...
Personally if Ansar can supply an 'SPX' at 500V + that would be a superb cap,i have massive regard for Ansar.. i doubt any other polyprop cap would be better in this situation tbh.. If you can accomadate a 2.5'' x 4.5'' cap inside your cooking. Martin T has one fitted to his Leak 'Stereo 20'.
Just to update this thread, folks... Anthony has just finished re-capping the PSU in my Copper amp. High-quality F&T (German made) electrolytics were used, bypassed with Clarity Cap MR polys:
http://img263.imageshack.us/img263/2350/s4010115.jpg (http://imageshack.us/photo/my-images/263/s4010115.jpg/)
Can't wait to hear it!! :carrot: :carrot:
Marco.
P.S Note the distinct lack of (sonically degrading) PCBs... Hard-wiring rules! :eyebrows:
Ali Tait
23-07-2011, 21:12
Looks good Marco.
Churz, dude! I've only been without it for 3 days, and I'm already having withdrawal symptoms.... :eek:
Marco.
Ali Tait
23-07-2011, 21:35
When do you get it back?
Rare Bird
23-07-2011, 21:39
Very nice wire-in'
Just to update this thread, folks... Anthony has just finished re-capping the PSU in my Copper amp. High-quality F&T (German made) electrolytics were used, bypassed with Clarity Cap MR polys:
http://img263.imageshack.us/img263/2350/s4010115.jpg (http://imageshack.us/photo/my-images/263/s4010115.jpg/)
Can't wait to hear it!! :carrot: :carrot:
Marco.
P.S Note the distinct lack of (sonically degrading) PCBs... Hard-wiring rules! :eyebrows:
Speaking as an old spark i have to say, beautiful wiring looms.
Cheers, Colin... And if it meets Andre's approval, that's saying something - woop, woop! :eek:
Ali,
I should get it back sometime next week :cool:
The Lockwoods have been missing it......
Marco.
Ali Tait
23-07-2011, 21:53
Let us know how it sounds mate.
Will do, matey! :)
Marco.
Was down at Anthony's place today, with Beryl, collecting my amp, so took a snap of Beryl (unusually in 'her' male attire :eyebrows:), surrounded by a trio of Copper amps:
http://img191.imageshack.us/img191/5599/bezas.jpg (http://imageshack.us/photo/my-images/191/bezas.jpg/)
Back row, left to right: Ian's (Beryl's) amp, then my amp. At the front, Anthony's amp, which uses double the amount of output valves, and is 60W Class A! :eek:
Marco.
Ali Tait
27-07-2011, 20:40
Very nice mate, how's the amp sounding?
I haven't plugged it in yet, matey! :eyebrows:
However, I heard it at Anthony's place and it sounded absolutely STUNNING :eek:
When we got back to mine, we went straight out for a curry, and now I'm too tired to have a proper listen (been on the go since 5.30am this morning), so gonna catch some zeds now, and will report back tomorrow :cool:
Marco.
All that copper porn is too much for my ticker.. :lol:
I know you'll have some fun running it back in Marco.
Cheers, matey - it'll be going in later :)
Never mind the copper porn, what about the Soul Monoblock porn behind! :eek:
Marco.
Mark Grant
28-07-2011, 08:39
Just to update this thread, folks... Anthony has just finished re-capping the PSU in my Copper amp. High-quality F&T (German made) electrolytics were used, bypassed with Clarity Cap MR polys:
http://img263.imageshack.us/img263/2350/s4010115.jpg (http://imageshack.us/photo/my-images/263/s4010115.jpg/)
The wiring looks fantastic, all nice and straight and neat and tidy and routed for techical reasons.
Its nice to see inside things :)
Cheers, Mark!
Guys, just an update on how the amp sounds since the power supply caps were changed..... After a period of burn-in, where initially the change had introduced an element of 'hardness' in the sound, the amp now sounds simply stunning!! The Clarity Cap MRs are definitely not for those seeking to create a 'sweet' or euphonic sound, but rather for people who value achieving a high level of accuracy and a genuine 'open window' onto all recordings.
The 30+ year-old Plessey electrolytic caps that were in the amp before were obviously well past their sell by date, and had introduced a slight 'mushy' quality in the sonic presentation of the Copper amp. Consequently, after having fitted the new F&T electrolytic and Clarity Cap MR polys, the copper amp has become a real 'animal', with seemingly endless reserves of headroom and power (through my Tannoy Lockwoods). And the bass, whilst not exactly lacking before (!) has gained more weight and extension, but with it, more control, grip and drive, resulting in foundation-threatening low frequencies, delivered with unflappable and consummate ease! :eek:
Honestly, with the right material, this amp sounds utterly frightening now... It may 'only' be 50W Class A, but it sounds as powerful and 'massive' as ANY 'powerhouse' solid-state amp I've heard, and in conjunction with my 95db efficient Tannoys, creates a palpable facsimile of 'live' music in my smallish (but perfectly formed) room.
However, not only have the cap upgrades massively improved the 'physical' presentation of the amp's musical delivery, but when delicacy and subtlety are called for, such as when teasing out inflections and wringing every ounce of emotion from the most sensual and angst-ridden of female vocals, the Copper amp presents them as shockingly vivid, for critical inspection, and with such a wide-open and crystalline clarity that the listening experience transcends that of a mere recording, and enters the domain of an almost live, 'living and breathing' musical event.
Consequently, I would recommend the combination of F&T electrolytic and Clarity Cap MR polypropylene capacitors to all DIY audio enthusiasts seeking to achieve superb results in power supply applications with all quality valve equipment! :cool:
Marco.
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