[jeffreybehr]

I'm getting very frustrated looking for these caps larger than 5µF and no higher than 4".* I have a pair of much-taller Capacitor Industries 50/660VACs, the lower one in this pic...



...to go in a separate box, outside my 845-based SET amp, and I bought a pair of 5/660VAC GEs from Allied to mount inside my amps, but I want something around 10 or 15µFs to add to it.

Capacitor Industries lists them... http://www.capacitorindustries.com/cbb65r.htm ...

...as does Commonwealth Sprague... http://www.comsprague.com/catalog.pdf , p. 14 ...

...but no one HAS any. C-S's minimum order is 250 units, so they're out. HOWEVER, Cap. Ind.'s minimum order is only 100 pieces, and the prices are LOW--the 10/660VAC, the largest value in the 'short/smalls', is only $2.83 each, while the equally short 25/660 is only $5.00 each.

Anyone interested in participating? I'm willing to manage the buy and will distribute at actual total cost. I expect I'd require a, say, 50% deposit in advance, as many of us can get VERY flaky/forgetful, etc.

BTW I considered using 440VAC caps, but my PS has about 980VDC on the 1st pole's cap and c. 970VDC in the 2nd, and I just didn't want to risk it.

* These are going inside ASL AQ1006(845)s, and that's all the height available. But even if I layed them down, I still couldn't find anything other than 50s.

[Folsom]

Have you gone onto diyaudio? What do you use them for? At that price I could buy one or two to try for something, but not 250.

[amplifierguru]

Jeffrey,

Have I discussed with you the myriad advantages of solid state?

Greg

[JoshK]

Why not try a good old MKP (metal'd polyprop) cap?  Stuff like Solen, Jantzen, TRT, etc have high enough voltage ratings and MKP is self healing (won't die after a number of surges, important in PSUs). 

Not saying the motor run caps aren't more efficacious, they may or may not be, but have you compared?  Paul and I tried comparing them in the Felicia and in that application, we felt they were clearly inferior sounding.   It could be that the applications are different, but I might be inclined to think they might be similar. 

Guys like Thorsten and a few other pillars of tube info have long advocated using such caps in PSUs for tube audio.  Granted a 10-25uf/600V+ MKP cap is big, but it shouldn't be as tall as a motor run cap.

If you are using these caps in the PSU as opposed to coupling, you are probably going to need a higher voltage rating then even the 600V rating. B+ for your 845 amp is around 1000V yeah, or is this cap a coupling cap?  Anyway, you can stack two caps in series with a voltage dividing series of resistors in parrallel and connected at the node (easier to draw, but it looks like an H) to lower the voltage seen by each cap. 

Let's say you have a WV of 800V B+ and you only have access to 600V MKP caps.  You create a voltage division with two resistors to create 400V and 400V and connect two of the 600V MKP caps from the division to the corresponding legs so that each cap sees a WV of 400V.  Voila!

Here is an example I quickly found from a tubecad.com article.  The left most pair of caps and resistors is the portion I am talking about, the rest of the circuit is about voltage doubling (useful when desiring high B+). 

[jeffreybehr]

"Have you gone onto diyaudio? What do you use them for?"  I've been a DIY hobbyist for about 25 years.  I use them for the purpose stated in my note--very-HV powersupplies.

"Have I discussed with you the myriad advantages of solid state?"  I've had them--thx, but no thx.

"Why not try a good old MKP (metal'd polyprop) cap?  Stuff like Solen, Jantzen, TRT, etc have high enough voltage ratings and MKP is self healing (won't die after a number of surges, important in PSUs)."  "High enough [sic] voltage ratings"?  600 does NOT equal 1000.  I do NOT want to use caps in series.  If I did, I'd use 400- or 600V-rated Solens and 370VAC-rated motor-runs.  The CLC-type PS will have a pair of 390/500 Panasonic TS-UPs in series in the 1st pole and something over 100µF of 'propylenes in the 2nd pole.  Since the Voltage from the powersupply becomes the very signal driven to the speakers, I want the very best-sounding caps I can afford in the 2nd pole.  These MRs are rated at 660 Volts AC, so the simple 1.41 multiplier gets them to 931VDC, and many MR-cap manufacturers rate them for DC at about double the AC rating. 

And, pray tell, Josh, bought 100 uFs of 1000V-rated TRT caps lately?  Let's see...a 4/425 is $30, so that's $60 for 2 uFs at 825VDC.  100 divided by 2 is 50; 50 times $60 is only $3000 per amp.  What a GREAT idea...NOT.

I've listened to this combination of Solen 51/1500 and Cap. Ind. 50/660VAC on the 2nd pole; it sounds significantly cleaner, quicker, smoother than the original 'lytics, so that's what I'll be using.

[JoshK]

Why all the sarcasm and vinegar?  I took time to try to be helpful and I get that?  have fun.   

[jonwb]

Why all the sarcasm and vinegar?  I took time to try to be helpful and I get that?  have fun.   

Don't sweat it Josh... you learnt me something!  I always figured there was a way of configuring multiple caps to accomidate high voltages.  Now I see how.  Thanks! 

[ctviggen]

800V?  Dang, don't stick your tongue on that!  You're getting into the area where you have to be careful. 

[Scott F.]

Jeffry,

Angela Instruments carries ASC run/start oil caps in 20uF @ 600v. Heres a quote from their site.

2. Angela/ASC Oil Capacitor, 20uF/600VDC, 1.75" diameter, 3.75" tall.  Rolled lip at the bottom of the cap requires an approx. .1875" larger hole in the chassis than 1.75". SALE! EACH $15, TEN FOR JUST $130!!!

Heres the link.
http://www.angela.com/catalog/capacitors/Ang_Poly_Oil.html

You'll still have the voltage issue though. If you really want to use the oilers, Josh's voltage divider should work just fine.

[jeffreybehr]

Scott, thx for the tip, but these are 600VDC, not AC.  I'd guess they're the 370VAC ASCs, but that's just a guess.

Josh, I'm sorry if I was sarcastic, but obviously you didn't think a whole lot or perhaps read my requirements.  I don't need a new PS; I already have two that work quite well.  I just want to put better-sounding caps in it.  BTW this PS feeds only the output stage; the frontend and bias supplies are completely separate after the power transformer, and the frontend supply is tube-regulated.

I believe (but don't know) that 2 caps in series sound twice as bad as a single one, so my goal is NOT to use caps in series in the 2nd pole of this PS.   For instance, I haven't yet chosen what high-quality film cap, if any, I'll use to bypass these 'propylene-in-oil caps.  I'm considering--
1. A 0.47/1500 auricap @ $17.50;
2. A '0.24/1200'* MultiCap RTX for $42;
3. A '0.24/1200' Rel. RT for $33 (Percy has them);
4. A '0.11/1200' SoniCap Platinum for $80;
5. A '0.24/1200' Cardas Golden Ratio for $60;
6. A '0.5/1200' Cardas GR for $90; and
7. A '0.024/1200' Hovland MusiCap @ $26.
Maybe the single, perhaps-slightly-lower-quality auricap will sound better than 2 perhaps-higher-quality caps in series.  If the Mundorf Supreme Silver/Oil were more reliable under Voltages approaching its 1200VDC rating, that's what I'd use, as they sound quite good...but they're not.  I guess I'd try the auricap or the Rel. RT first, but that'll happen only after the new PSs have at least a few-dozen hours on them.

Again, I've compared the sounds of these 2 mono amps (in mono, of course) with the different 2nd-pole caps; the amp with the 'propylenes sounds cleaner, quicker, AND smoother, a combination that's not always achieved.
.

* These caps in quote marks are actually 2 caps in series of double the value and half the Voltage.

[JoshK]

Josh, I'm sorry if I was sarcastic, but obviously you didn't think a whole lot or perhaps read my requirements.  I don't need a new PS; I already have two that work quite well.  I just want to put better-sounding caps in it.  BTW this PS feeds only the output stage; the frontend and bias supplies are completely separate after the power transformer, and the frontend supply is tube-regulated.

Who said anything about rebuilding your PSU?  I sure didn't.  I was talking about using MKP caps and how you could use ones of a bit less voltage rating.  This is directly applicable to your question and requirements per your first post.  Never did I ever imply anything close to rebuilding your PSU.

I read your post, I did think about it and frankly think you are the one who didn't think about what you wrote, but that is all I will say on this.

I believe (but don't know) that 2 caps in series sound twice as bad as a single one, so my goal is NOT to use caps in series in the 2nd pole of this PS.   

Based on what?  I've never heard of such, nor does it make any logical sense why that would be. 

Maybe the single, perhaps-slightly-lower-quality auricap will sound better than 2 perhaps-higher-quality caps in series.  If the Mundorf Supreme Silver/Oil were more reliable under Voltages approaching its 1200VDC rating, that's what I'd use, as they sound quite good...but they're not.  I guess I'd try the auricap or the Rel. RT first, but that'll happen only after the new PSs have at least a few-dozen hours on them.

Again, I've compared the sounds of these 2 mono amps (in mono, of course) with the different 2nd-pole caps; the amp with the 'propylenes sounds cleaner, quicker, AND smoother, a combination that's not always achieved.
.

* These caps in quote marks are actually 2 caps in series of double the value and half the Voltage.

But you got your mind made up so have at it.

[jeffreybehr]

My, my, you really do go off half cocked, don't you?

Why would you recommend caps of lower Voltages such as the TRTs if you didn't think they were useful?  I think my comment about not wanting to follow your lead on the TRTs to build a $3000 PS was a reasonable response to your not-thoughtful suggestion.

And no, I don't have my mind made up about bypass caps that you quoted, as anyone who READs my comments can see.   What do you suppose the italisized 'maybe' means?  Do you not understand English?

Jeez!  I start a note about helping anyone who might want some great-sounding caps useful for 1000VDC supplies, and you suggest PSs based on $3000 of capacitors.  I guess it's true--no good deed goes unpunished.

G'bye Josh.  If anyone is interested in participating in this possible purchase, pls e-mail me and DO NOT post here; I'm finished with this.