Music Man Capacitors

[WholeToneMusic]

Does any one know where I could get some replacement caps for a Music Man RD100. I usually use Sprague Atom's, However some of the uF values are not common on this amp. I would rather not use any Taiwanese capacitors. Any suggestions for a good source?

Thanks

[Enzo]

Come on, help us out here. WHAT caps are you looking for?

I am assuming electrolytics, but is that all?

In many cases, especially with electrolytics, you can run into one guy calling it 50uf and another calls it 47uf. SO you look for 50 all over and all you can find is 47. CLose enough. Or maybe you want 75v and all you see are 63v and 80v, or something. Or 20/22/25uf. These are not critical values.

In some older amps, values like 8uf and 16uf were fairly common, but no one makes those values anymore. 10 and 20 are close enough.

[WholeToneMusic]

That's understandable, I was looking to replace the Electrolytics, Coupling caps and bias supply caps. Some of the one's I am looking for are not standard by any means, 150uF @ 3 volt
20uF @ 50 volt
.1uF @ 100 volt
.047 uF@ 250volt
400uF@ 25 volt
150uF @ 50 volt\100uF @ 450 volt
There are some caps labeled Plessey in the amp that have the #'s 150 &1/10/100 on them with no voltage rating. The caps measure 1uF when tested.
Anyone familiar with these?

Best Regards,
Brian

[Enzo]

I don't have the RD100, I have the 50. is there a chassis number on the back of the amp?


I am assuming you want all axial leads?

150/3v? Use a 10/16/25/35 volt instead. You can always use higher voltage caps than you need.
Mouser 75-TVA1207.5 $2.28 Sprague (25v)


20uF @ 50 volt?
Mouser 75-TVA1305.5 $2.07 Sprague

.1uF @ 100 volt?
Mouser 75-225P100V0.1 $1.25 Sprague
But it doesn't have to be 100v, looking at 400v:
Mouser 539-150104K400EC $0.55 Mallory


.047 uF@ 250volt? Don't you have some 400 or 600v ones in the drawer?
These are 400v.
Mouser 539-150400V.047K $0.52 Mallory 150
Mouser 75-715P400V0.047 $1.39 Sprague orange drop

And so on.

Is the 150/100 cap a can? REplace it with two discrete caps.

I don't know what the Plesseys are at the moment, I'd look them up on the schematic with a chassis number

[WholeToneMusic]

Thanks Enzo, I could not find the schematic for the RD100, The closest found was the RD50, the amp you have. the 150/100 is the physical #'s on the Plessey caps. The chassis # is 2100-RD-CAL

[acorkos]

2100 RD schematic:

http://www.ernieball.com/mmonline/te..._&_2100-rd.pdf

[Enzo]

Yep, 2100-RD was what we needed.

FInd the mystery caps in the schematic, and we can determine what they are.

[WholeToneMusic]

Thanks all, I will look up the values and get back.

[oc disorder]

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(just thought you may have missed this ...O.C.D.)

[WholeToneMusic]

The plessey caps are interesting, 1 of them goes to the wiper of the gain pot and another goes to the other lug, The schematic looks as if they are 20uF with no voltage rating, The meter reads 1uF on all of them tested, my gut is telling me to go with the 1uF. (whats the chances of all the plesssey caps drifting to the same value?) Thanks for the link OC.

The plessey reads

PLESSEY
150
1/10/100

[Enzo]

Are they bad? Leave them in place.

[Amp Kat]

I wouldn't trust the meter testing capacitors as it's not very accurate. You really need the schematic to tell for sure or find someone who might have one. Sometimes you can find pictures on the net or pictures on ebay. Do yourself a favor and cut one of those Sprague caps open and see what you find inside and it may sway your opinion on how superior they are to International caps. Also agree if the existing are good let them stay.

[mac1amps]

It's really very rare for coupling caps to fail in an amp that is that "new' (i.e. since the later 50's, virtually all signal capacitors are epoxy coated, which makes ALL the difference). In SPITE of this, the newbies always get obsessed with wanting to change them anyway ('go orange drop dude! they're awesome!!...........'sorry, just kidding).

[WholeToneMusic]

I replaced all the electrolytic caps. There was no DC leakage on the other caps so I left them in place. Thanks for your support.