Caps for Peach

[Fjd]

The Hovland is a very nice film and aluminum foil, and these will always sound cleaner and more transparent than all but the very best of the metallized types. The Auricap, though a metallized capacitor, is a great part, and there really isn't any reason to move away from it. I was looking for some polystyrene film caps, and I found some, but they only went to 3uF. Jupiter Flat Stack Films would be awesome, but they are too big and they're challenging to mount. Parts that can't be easily inserted/integrated onto the existing board should be ruled out. There are no film and foils that I'm aware of that will work here, so we only have metallized caps to choose from. That's okay though, because there are few that sound a little more open than the Auricap.

Mundorf Supreme, 800Vdc

Jantzen Superior Z, 800Vdc

I run the the Jantzen Superiors in my personal crossovers, they sound cleaner to me than the Auricap (which I tried first).

So far I have not felt the need to swap capacitors in my Bluberry Extreme or Peach (both have the Auricaps), but may see what the budget can withstand at some point. However, there sure are some interesting choices if there was enough space.

With one of my single-ended point-to-point amplifer builds, I've swapped in the Mundorf Supreme Silver/gold/oil (previous cap was a Cardas with a Mundorf Silver/oil bypass) and liked what I heard better (although subtle like spicing a very good pot of chili and turning it into a very memorable pot of chili); however, Silver/gold/oil are just over Mark's dimensions (~ 1.77" W x 4.17" L) and would be extremely expensive over the two .22 uF capacitors used in my amplifier.

The difference between the $55 capacitor that is now in your Peach, and a $300 one that you might buy to replace it, is um, very, very subtle. It would only be heard by very careful, attentive, dedicated, listening under ideal conditions.

Note to self: Do not schedule a couple cap listening competition while mucking about in the basement with pneumatic nailer, circular saws & right angle drills and wearing 30 db over ear hearing protection at the same time.

If you did upgrade the capacitors in the Peach, it would seem that the Dx 38 would need to have upgraded caps, resistors and maybe inductors too.

[erik2A3]

I have a need to keep this brief, but my thinking and experience with AC coupled circuits like this is very much in line with Mark's. I had the Peach here years ago when it stopped by our house during its introductory road tour, and didn't have even a mild inclination to dive in to start yanking out its interstage coupling capacitors in the name of hoped-for improvement in performance. I have built my own preamplifiers and amplifiers using the same capacitors that had been originally installed in the a Peach. They are very well-made, and in my experience, very good-sounding and reliable capacitors.

I also agree with Mark the the effects of brand changes of capacitors in this application can be extremely subtle. As someone who has been described in the past as a sort of naysayer on this subject -- that capacitors do NOT make a difference -- I would say that assessment reflects a lack of understanding of what my premise has always been: that capacitors CAN and often DO sound different. In my experience, however, it has not always been the case where the capacitor (or resistor or any other passive part for that matter) that required the greatest financial investment was the one that ultimately sounded the best in a given application. In fact, I know of extremely competent and knowledgable designers who made the very conscious choice of coupling two stages with a high-quality and sonically transparent electrolytic capacitor.

The design of a given circuit is by far the most crucial element; a better (or more expensive) part is not going to improve a design that is already flawed or compromised.

There are also those who automatically bypass what had been judged to be a poorer quality capacitor with a small value film type capacitor, and in some cases there may be an advantage to doing that -- but not always. Where a circuit calls for a certain value of capacitance that may be a higher value than what is available in a particular preferred brand, it is perfectly suitable to parallel different values in order to achieve the desired value, keeping voltage ratings in mind -- which is important, particularly in the presence of high voltages: if one parallels a 25V capacitor with one of 800V, the resulting capacitor may equal the desired value of capacitance, but will only be as good as the 25V cap in terms of working voltages.

Paralleling capacitors can in fact have benefits beyond creating a desired value of capacitance.

The thing about the Peach is that it already had perfectly good coupling capacitors as designed! Where circuit boards are used, one has to be careful, as Dean mentioned, in removal and installation of PCB parts. Solder pads on PCBs can be fragile, and can lift up with too much abuse or yanking in and out of parts.

....erik

[Deang]

"I have a need to keep this brief..."

You're such a kidder. : )

[DoubleJ]

Second... what would the enhanced power supply do for the common fruit?

There are three parts being changed in that mod. The 12X4 rectifier, the 6.3V bridge rectifier and the 3A regulator. All these are being changed to improve long term reliability. The 12X4 will be replaced with SS diodes, the bridge is being changed from 10A to 30A and the low voltage regulator is being changed from 3A to 5A.

Mark:

I may be interested in this upgrade/mod so I'm going to contact you via email to get the particulars.

Thanks

JJ

[erik2A3]

Dean: I thought it was going to be short and to the point.....sadly never the case with me, as you well know!

Mark: I think it's great you're set up to make these changes. I few years ago I rebuilt a 22 tube OTL amplifier for someone who all but destroyed the PCBs in his amp from attempts at coupling cap modification -- in one case while it was energized, and blowing the power supply board in the process (not the smartest thing to do for more than one reason -- which he admitted). The repair included ordering a multitude of diodes, Zener diodes, piles of resistors, voltage regulators, an army of large and small electrolytic caps, film caps, a new board, re stuffing the board, and reconnecting filament and plate supplies -- crazy. I did it for free, minus cost of parts, which was probably even more crazy. Time and time again people go for the coupling capacitors, and often spend hundreds of dollars in the process. And that is without a doubt someone's right to do if he or she so chooses. I have experimented myself, with both PCBs and point to point. So, I'm as guilty as anyone....

Absolutely. I know you would never encourage a former customer or owner of one of your products to do that kind of work themselves. Good of you to take those projects on!