Vintage electronics questions

[_DK]

Hi,
I've got a capacitor in my amp which I believe needs to be changed (re-caped), it reads:
"RIKEN
10 MFD Red
10 MFD Red
2 MFD Yellow
350 WVDC
CAN-NEGATIVE"

I haven't found anything like it on the web stores. What should do? The amp is from late 50s.
Sorry if this is a wrong forum section.

 

[crazydoc]

You may be hard pressed to find an exact or close match for this. However, you can buy two 10uF and one 2uF caps and wire them into the approprite circuit lugs: positive leads go where the colored wires go, and negative leads all go to the can's ground connection.

Here's a site that sells them cheap (unfortunately $15 minimum order) - any rated at 350V or above will do - less than $3 for all. You could even take the guts out of the old can and cover the new caps with it if they fit, and it will keep that vintage look.
http://www.justradios.com/orderform.html

or Digikey, even cheaper:
http://www.digikey.com/scripts/us/dksus.dll?Detail?name=493-1215-ND
http://www.digikey.com/scripts/us/dksus.dll?Detail?name=493-1218-ND

I imagine these are power supply smoothing/filter caps in your amp.

 

[_DK]

Thanks! I think that's what I'm gonna do.
I'm just assuming that 350 VDC = 350 WVDC? I've never seen one with a "W".


Hmm...what happened to my rep power?

 

[Track Rat]

Doc is correct in that it's 3 caps in 1 can. You'll have a REAL hard time finding a direct replacement. Just buy 3 seperate caps of the closest value you can find. Make sure you get at least the same or higher voltage rating.

 

[crazydoc]

Thanks! I think that's what I'm gonna do.
I'm just assuming that 350 VDC = 350 WVDC? I've never seen one with a "W".


Hmm...what happened to my rep power?

"One very important rating of capacitors is "working voltage" (WVDC). This is the maximum voltage at which the capacitor operates without leaking excessively or arcing through." I don't know why they use it with caps, but it just means the highest voltage the cap should see in the circuit.

I guess you pissed of a high-powered repper - I'll give you some pos rep.

 

[_DK]

Thanks again

 

[Light]

According to people who know a lot more about them than I, a lot of vintage amps used caps which were under-rated for the voltage levels in the amp, which is a bad thing. It would not be a bad idea to get caps with a rating of 400V.


Oh, and avoid Sprague Atoms. Whatever the vintage wienies say, they are poorly made caps. The big gray Illinois Capacitor ones are the way to go.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[Lectric_Lab]

hope you all don't mind if I ask a question...I don't know much about amps internals and need guidance. Where can I find a transformer for a 70's silver face Fender bandmaster head, think its 50 watts. Mine smoked. Hope its okay if I butt in here. Thanks

 

[Track Rat]

Heyboer and Hammond will have transformers.
http://www.heyboertransformers.com/index.shtml
http://www.hammondmfg.com/

 

[crazydoc]

hope you all don't mind if I ask a question...I don't know much about amps internals and need guidance. Where can I find a transformer for a 70's silver face Fender bandmaster head, think its 50 watts. Mine smoked. Hope its okay if I butt in here. Thanks

Is it the power supply transformer, or the output transformer? Additionally, you need to find out why it smoked. If you just replace it, and the original problem still exists, you'll burn the new one too.

 

[dementedchord]

yeah i'ld increase the voltage to 400 or so and maybe even double the capacitence... unles your going for a real creamy output compression...