[markmaloof]

I am getting around to putting together a Cornet after having the darn board for a year or two (yeah, I know, what took me so long?)  I have been turned on to Jantzen caps, new to Parts Express, and very inexpensive (at least for now.)  I bought four .47  uf for C1 + C3, and two 1 uf caps for C6.  The caps, however, are rated for 400 V, not the 630 of the poly caps from Mouser.   Think I'll be ok with these?

Also going nuts with the whole power supply cap thing, at this point may just stick with Jim's recomended Xicons, except for some Nichicon 10,000 Uf 10V caps from Welborne (have to order jacks and some male rcas from Ron anyways), and maybe go for the Panasonic 47uf  electorlytics also from Welborne.  Probably better to stick closer to stock to start out with, though some folks have suggested large Polys (Solens, etc) instead of electrolytics for the power supply.  I do have concerns about fitting them to the board, and also since I'm still only semi-skilled with kit building, should not stray too far from the path.  But I want the darn thing to sound very good off the bat, have revealing Innersound electrostats and a nice Redpoint/Galibier turntable.

[avahifi]

Do you have any information about what the actual voltage across those capacitors is in circuit, both at initial turn on and steady state?

Using a capacitor with a voltage rating lower than the actual circuit requirements risks quick expensive failure.

On the other hand, if a capacitor is used in an application with a voltage significantly lower than the parts rating, that can be bad too.  Why?  Because many types of capacitors do not make their actual capacitance rating when significantly undervoltaged.  This could change timing and pole point values and change the circuit performance in unpredictable ways.

Many major parts manufacturers have application manuals available as free downloads.  Its a great place to start learning a bit of electrical engineering basics.  Not as much fun as audio voodoo, but actually more rewarding long term.

Frank Van Alstine

[hagtech]

Oh my, Wes finally convinced you to dump the ESL57s?  Are you driving the Innersound with the Citations?

The 400V caps will be fine.  Electrolytics in supply not the last word, but the films that bypass them are.  Good films everywhere in the circuit really helps.  But I don't like to mix two films in parallel (one big, one small).  The electrolytic has enough ESR to prevent any odd ultrasonic issues.  Too much of a good thing can be possible; a dead short leads to infinite current, etc.  

The other good upgrade is to switch to the 370BX tranny.

jh

[markmaloof]

First off, I had 63 USA Monitors, not 57s (though a refurbed pair of 57s had perhaps the most transparent midrange I have ever listened to.  Amazing.)  After having to repair one panel, and seeing more panel repairs in the future, I picked up a used pair of Innersounds, have upgraded to the latest crossover amp and ESl amp, and will soon upgrade to the lastest arc-proof panels (a benifit of the Innersound over the 63s.)  And now I have real bass...it has spoiled me, making me realize what I was missing with the 63 USA Monitors (still a great speaker.) Also, the panels extend to 27K, instead of starting to roll off at 16K like the 63s.  No, the Harmon K. Citation V would not drive the Innersound panels properly.  Yes, it worked, but rolled off (the Innersounds dip to below 2 ohms in the highs.)  Monarchy SM70 Pro monoblocks (class A SS amps) worked much, much better, but once I popped in Innersound's amp, game over for sure (duh, it's made to drive difficult loads.)  I have a Music Reference RM9 that is being worked on, and I'll bet it will have nice mids, but I also bet that even though it's a tube amp meant to drive difficult loads, it will still sound a bit dark compared to Innersound's amp (which does not make me miss tube amps that much.  But tubes before it are nice!)

So, I guess I will stick with the Jantzens in C1, C3 and C6. Maybe later try a pair of Sonicaps in C6, though the Jantzens are good for the value (and I just remembed that I wanted to get a Jantzen for C5, but they were out of stock, so I just grabbed a pair of Dayton film and foil .1 uf for that.  Figured it could be no worse than the Mouser caps, and they are rated for 400V, more than the 250V caps in the original design.)  But I guess I should return the Hammond Trannie to Parts Express (nice that they take returns.)  Then get the 370BX.  Parts Express, I believe, does not carry it.  Anyways,  what changes do I have to make in the Classic Cornet circuit to make that transformer work? Also, there is a current sink mod (or something to that effect, right?)

[hagtech]

Details in this thread...

http://www.audiocircle.com/index.php?topic=4328

jh