Switching out capacitors...?

[Guest]

Hi folks,

From looking at the pictures that have been posted to the site and from reading some of the other threads that have been posted (boutique parts, etc) it's obvious that lots of you guys (maybe almost all of you) are using different parts than the parts sheet calls for.

First off, I think that's great....I didn't want anyone to think I was saying otherwise. That's why we all get into this DIY thing in the first place, to do it ourselves and our own way, right?

With all of that aside, I ordered most of the parts I needed from Mouser the other day. They arrived a few days later, but the 450V 22uf capacitor was back ordered.

They also shorted me one of my pots. So, this morning I gave them a call to ask about those two items. First off, they were happy to send me the MIA pot, no questions asked. That's costomer service. They also told me that the capacitor (140-XRL450V22) was back ordered until the 18th of this month. SO, if any of you are planning to start a build shortly, you might want to take this into consideration.

I then asked him if he could cross refference that part to something with the same values and the same approximate size/shape. He did, and we ended up with a Nichicon part (Mouser P/N:647-UVZ2W220MHH). It has the same lead spacing and roughly the same case dimensions. Saddly, it does cost $2.25/cap, but since there is only one or two in the whole amp i was willing to make the "huge finacial investment."

So now for the all important question: Was this an OK move on my part? Is there some terribly wrong with Nichicon parts? Will this single part make my entire amplifier sound like junk, catch on fire, and ultimately destroy my life?

Since this capacitor is in the power section I though "hey, even if there is something sub-par about this device, at least it's on the DC side of things and not on the audio-portion of the circuit." Right? So I think my substitution was ok.

The other thing that the Mouser guy mentioned to me was that the 105degree temp rating (on the Nichicon) would be better on the power supply....do the caps run fairly warm in this thing? Is there any prudance in upgrading all of the caps to high-temp (105degree) units? Or does it run cool enough that 85degrees, and much less 105degrees is superflous?

Thanks for your time everyone!
drew*

[Guest]

So now for the all important question: Was this an OK move on my part? Is there some terribly wrong with Nichicon parts? Will this single part make my entire amplifier sound like junk, catch on fire, and ultimately destroy my life?

Since this capacitor is in the power section I though "hey, even if there is something sub-par about this device, at least it's on the DC side of things and not on the audio-portion of the circuit." Right? So I think my substitution was ok.

The Nichicon is an upgrade, IMHO. That swap was fine.

The other thing that the Mouser guy mentioned to me was that the 105degree temp rating (on the Nichicon) would be better on the power supply....do the caps run fairly warm in this thing? Is there any prudance in upgrading all of the caps to high-temp (105degree) units? Or does it run cool enough that 85degrees, and much less 105degrees is superflous?

Thanks for your time everyone!
drew*

105C caps are another upgrade. Needless to say, tube amps generate a lot of heat and this will definately add life to the amp. Everything is relative, though. A DIY amp should outlive every other single audio component you have. Nor would I worry about any 85C caps in there. MTBF goes <way> up even at 70C and I guarantee your amp won't be anywhere close. Unless you sit them on the power transformer.

BTW, nice support from Mouser. Very helpful gent, indeed.

Shannon

[JG]

Hi,

I've got some auricaps, but the leads on them are thicker than the holes on the pc board.

What can anyone suggest? Should I drill them out a bit thicker?

Thanks,
JG

[Shannon Parks]

What can anyone suggest? Should I drill them out a bit thicker?

What is their physical size? I personally like to scrape some the solder mask off the trace then tin it for jobs like this. Then you bend the wire like an 'L' and solder surface mount-style. You would have to drill through one of C2's holes - but then you would just do the same solder-to-the-tinned-trace procedure. I've done this when replacing R43 with a choke.

Shannon

[EWBrown]

I have some of the same Auricaps. The cap body is much smaller than the "orange drops", but the leads are fairly thick multistranded wire.(same as used in the larger Hovland Musicaps). it isn't absolutely necessary to run the leads through the holes, indeed, drilling them out will remove the plated-through hole amd may break other connections made through it. Two approaches here: After stripping off the red and green teflon insulation, just start removing a few strands at a time, until it fits through, or just top-solder the leads, without pushing them through. You want to leave some slack in the leads in eiaher case, and strip the insulation off carefully, it can be pulled out of the cap body. this won't "kill" the cap, but it does ruin the visual aesthetics.

I've used both the original "orange drops" and the Solen .22 uF /
630V "fast caps" (smaller than the ODs, and only a little more $ for them).
I wanted to try .22 uF to see if there was any discernable difference in bass responce, I didn't readly notice it, but only a side-by side test will prove that out.

I have used both the Hovlands and Auricaps, but those were in point-to-point wired SE amps, and on one Dynaco ST-70 PC3 board replacement.
Maybe on the next Rev C in the future..


/ed brown in NH

[Shannon Parks]

...After stripping off the red and green teflon insulation, just start removing a few strands at a time, until it fits through...

Slick idea! I seem to do this naturally as I'm dangerous with a wire stripper.

Shannon

[EWBrown]

As long as the replacement caps have the same or higher voltage rating, and are physically compatible (ie the fit) then it's good to go with. The Nichicon caps are very good quality, the 105C rated ones are best, and I think these also have a lower ESR, which doesn't mean much at 60Hz but gets important for higher frequency switcher power supplies. THe capacitancew should be at least the same, more uF won't hurt, the CL90 inrush current limiter takes care of any issues here. The tolerance ratings on electrolytics are fairly broad anyway, so the absolute vaslue isn't a major issue.

Hmmm, I just made an order to Mouser last week, including some 22 uF 450 V caps - -maybe I got the last ones... I had to wait a bit for the CL-90s from an earlier, but they arrived in a couple weeks.
One more order soon, to AES or ANgela, for chassis, isolated input jacks, output binding posts and some ceramic tube sockets for yet another future project.

/ecd B

[merlin2049er]

Ok, Thanks.

I think I'll bend my leads and solder them to the top of the board.

Thanks,
JG