Vintage Webcor Reel to Reel Cap Value Replacement

[tomcurrie]

I picked up an old Webcor 2130 Reel to Reel on Craigslist last night and want to recap it.

The Multi section caps are:
35uF/300V
35uF/300V
15uF/250V

Seems like the closest replacement caps for the 35's are 47's. Just want some thoughts on replacing those 35/300's with 47/450's. And also the 15uF/250 with a 22uF/450

Thanks

 

[Mickeystan]

The proposed replacement caps will likely be fine. It would help to see a schematic of the unit. If one of these is first filter cap following a tube rectifier, be careful to not exceed the tube's maximum input cap size limit in uf's. If it is solid state rectifiers, it will not be that critical. I truly suspect you are totally Ok if the it is not tube rectified as mentioned above.

Micketstan

 

[tomcurrie]

rectifier

It has a 6X5 rectifier tube with the 35/300 going to cathode.

 

[Mickeystan]

The 6X5 rectifier tube is listed for 4uf input cap on all the data sheets I can see. Obviously, the Webcor designers thought it would be OK with a 35uf cap as the input cap which is surprising to say the least. I sure would not recommend that you replace it with anything higher than what they had in that position. In fact, you are probably better off if you replace it with a smaller value which is closer to what the data sheets recommend. I would try this and see if you have any substantial hum problems.

Mickeystan

 

[Eli Duttman]

Tom,

I guessing the B+ filter is CRC. I'd go with 15 μF. in the 1st position and increase the capacitance in the reservoir position.

Per the TungSol 6X5 data sheet, to use a 47 μF. cap. in the 1st position, replace the wire between the 6X5's socket and the cap. with a CL-90 inrush current limiting thermistor.

 

[barrymagrec]

The Mullard data for the 6X5 gives 32uf as the maximum C with R min of 150 ohms per anode - this is the total of the transformer secondary resistance and the reflected primary resistance. This figure appears to be with the maximum 325-0-325 input, it would probably tolerate a slightly larger C with lower input voltage.
I`d be inclined to go with the above suggestion to use a lower primary cap and a larger smoothing cap further on.

 

[tomcurrie]

There's also a .5uF/50V wax cap in there...it's all gooey....can I just replace it with a .47uF/630V Mallory Cap. The voltage rate doesn't really matter on these caps does it?

 

[Mickeystan]

There's also a .5uF/50V wax cap in there...it's all gooey

I would recommend you replace it too while you at it. The cap value of .47uf is close enough and the voltage rating needs only to be equal to or higher than the part your replacing. Getting rid of old wax caps is a good idea in vintage gear. Your on the right track!🙂

Mickeystan

 

[tomcurrie]

I replaced all the e-caps and finishing up these wax caps today. Cleaning the tape heads also.