View Full Version : Caps for a Sherwood S5000


CDFixer
08-04-2004, 09:08 PM
I am looking for some capacitors for a Sherwood S5000 amp. I have the diagram and the values of the Caps are .068uf the diagram does not give a voltage.

The part number on the cap is A680 A4, attached is a picuture of the 5 lead unit, the others are 6 lead but are also labled A680, with various suffixes, A1, B2, J1 They are all Sprague Caps.

Any help, This is my first tube amp to work on since the early 60's.

wsjoe
08-05-2004, 10:28 AM
Jim,

You forgot to put the schematic. The one I sent you earlier was a regular S-5000, but tube amp in question is an S-5000 II.

CDFixer
08-05-2004, 11:49 AM
Thanks WS, here is the picture that I was going to post.

Tom Bavis
08-05-2004, 03:20 PM
These centipedes are called PECs (Printed Electronic Circuits). If they say CRL (Centralab) I may have data on them on my page - if they're Sprague... dunno. But they're ceramic caps inside so they're probably NOT leaky.

My Tech Page (http://www.audiophool.cjb.net/Techno.htm)

CDFixer
08-05-2004, 03:28 PM
If you look real close, I have an advantage, I can see the real thing this one has a bulge on the side and is discolored. Yes they are Sprague. I have found them in the schematic and they are 680 UUF and 400v. I may have to replace with indivdual caps, but my electronics store is going to let me go diving in there old warehouse where there is an old Sprague display center with drawers of old style NOS caps.

I am looking forward to it. Never know what you will find. You should see the second floor of the store all kinds of vintage stuff up there.

dshoaf
08-05-2004, 05:26 PM
<< pardon the pun>>

Lots of older tube gear used these, including Mac stuff. These were generally used for tone control circuits or other places where frequency shaping was required.

These will have used standard components - carbon comp resistors and ceramic caps for the most part. They reduced the time needed to install and lowered manufacturing costs in point-2-point wiring in those days.

I doubt you'll need to mess with them and would recommend you confirm that the tone controls are working prior to any updates you're planning.

If you do decide to replace them, its almost as good just to plan on building your own PECs with individual components and mount them to a small piece of circuit board material. I'm actually thinking about doing that with one of my Mac MX-110s just to see if it would make any difference. So far, though, I'm happy with the original Sprague PECs that still reside there.

Hope that helps.

Cheers,

David

CDFixer
08-05-2004, 07:50 PM
This particular one is used between the Plate and cathodes of the drivers to the grids of the 4 output tubes. It is used as a DC Blocking cap if I am not mistaken. I haven checked this one out but belive because of the discoloration and bulging that it is probably defective.

More later.

NOSValves
08-05-2004, 09:26 PM
Is your amp a S5000 or a S5000 II they are very different animals

Craig

wsjoe
08-05-2004, 09:41 PM
The amp that Jim and I are working on is the S-5000 II.

wsjoe
08-05-2004, 09:43 PM
Here is a picture of the back...

wsjoe
08-05-2004, 09:44 PM
Here is a picture of the back...

More can be found at...

http://photos.yahoo.com/wsjoe

NOSValves
08-05-2004, 09:53 PM
Well if you decide to replace the PEC's you will have to devise a way to wire the components that your replacing if were talking about the PEC (named P10 and P9) off pins 2/6 of the phase splitter in the S5000 II it incorparates a 12k 270K and 200pf cap I would be seriously surprised if its bad. There looks to be a boat load of PECS in this amp.

Craig

CDFixer
08-05-2004, 11:41 PM
There are a boat load, the one I am really concerned about is the one in the above picture, it is discolored and bulging. based on the schematic it is connected to the junction of the 1k resistor and a .068uf cap. What is confusing is none of the PECS are shown on the schematic it that position. The diagram has a 150K resistor at that junction. I have only been reseaching this with photos and schmetics, I haven't seen the real thing as of yet. Maybe next week.

Cheers Jim

NOSValves
08-06-2004, 12:41 AM
It's almost impossible to trace these things out from a photo heck its confusing enough at times to do it with the amp on hand ;) The way the schematic shows the PEC is in front of the .068 coupling cap and has a 47K resistor between the PEC and the .068 cap. I'm referring to P10 and P9 is this the PEC your talking about ?

Craig

Chad Hauris
08-06-2004, 07:31 AM
I think the bulging is normal...there are capacitors inside this device covered by a coating...it is most likely ceramic caps and there is nothing that can swell up like in an electrolytic cap, you are just seeing the outline of the components inside under the coating.

NOSValves
08-06-2004, 12:04 PM
Chad is correct the bulge is the Cap inside the PEC. I only replace them if they house the main coupling caps. I did this not long ago to a EICO ST40 and the improvement was excellant. But the position of this PEC is not crucial to the sound. I bet its fine.

Craig

CDFixer
08-07-2004, 02:01 PM
It wasn't so much the bulging but the discoloration that bothered me. I will be getting the amp today and will be able to check it out better.

Thanks for all the help