• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Recapping my Pioneer SA-6500II amp -- need advice

soundweasel

soundweasel

Super Member
I can't stand the "pop" when powering up the amp so I'm going to recap the unit myself.

I've put together a list of caps in the unit and compared it against those available at Parts Express, and, in the cases I can't locate replacement caps of the exact value. For example, I need to replace two 220uF 6.3V caps. The closest match I can find are 200uF 16V. Will these work or must the voltage be exactly the same as the original cap?

Also, the available replacement caps on PE seem to physically much smaller than the ones currently in the unit.

Will these work OK in the amp?

http://www.parts-express.com/wizard...=1&srchPrice=&srchCat=157&srchMfg=&srchPromo=

Any other suggestions on where to get replacement caps.

Also, before I go and replace 18 caps, is there something else that could be causing this "pop" when the unit is turned on? :scratch2:

Thanks,

Doug
 
Register to hide this ad
Going up in voltage alittle would be ok IMHO . Newer caps are smaller due to miniaturization in the electronic field over the years .They will still be better then the 30 year old caps in there now .
A good place to start would be the caps in the power supply .





Barney
 
If you're going to this much trouble, buy better caps. I would honestly not want an amp full of Xicon caps.
 
www.mouser.com. They've got just about any value cap you might need, at good prices. I bought Nichicon's "audio" grade caps for a couple of receivers I'm working on...going to order more for some other projects.
 
I think those use caps in a timing circuit that cut off the bias to mute the output. I would suspect caps in that area.
 
lumpy said:
I think those use caps in a timing circuit that cut off the bias to mute the output. I would suspect caps in that area.
Click to expand...

Lumpy:

Could you do me a huge (I mean HUGE) favor? If you have a 6500II could you (please) pop the top on it and snap a photo of the exact area you describe? I'd rather replace the caps in that area first to see if it cures the problem, rather than re-do all the caps.

My diagnostic abilities are non-existent so I need someone to physically show me the location. I'm such a spaz sometimes. :sigh:

Please let me know if this is possible.

Many thanks. :thmbsp:
 
The parts in question are near tp-3 I have a board layout but not a schematic. Send a photo.
 
Page 8 of the service manual does a nice job of explaining the muting circuitry. Page 9 shows a simplified schematic of same.
 
Caps. For polarized electrolytics, I look for what I need in the Panasonic FM. If not available, I check the Nichicon HE. If not there, I check the Panasonic FC or Nichicon PW. For signal path electrolytics, I've been using Elna Silmic II caps lately with very good results. For small value electrolytics (1µf - 100V and under), I try to replace with a Panasonic stacked film cap. For non-polar electro's, usually a Panasonic SU will do fine (if it is a non-polar axial, I find a way to neatly incorporate a radial lead cap rather than resort to a cheap speaker crossover-type electro). For axial lead polarized electrolytics, Vishay/BC Components AML 138. If I can't find a proper axial lead cap, again, I try to find a way to neatly shoehorn in a radial lead cap.

When buying a radial lead cap, you are often given a choice between a short & fat cap, or a tall & skinny one of the same value & voltage. The short & fat one will have a longer life and better specs, and probably fit better in vintage gear considering the reduction in size of electro's over the years.

All the above are available at Digikey.

Replacing large-can power supply caps is a whole 'nother subject that I'm not going to get into here.

/Forrest Gump voice: 'And that's all I got to say about that'.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom