EL 84 Capacitor Equivalent

[WessieNC]

Hi there. I've salvaged an amp from a Bell and Howell projector and want to re-build the amp for general audio use.It uses 4 EL84 Tubes on the main output stage and 1 ECC83 in the pre-amp stage.
My question is:
I am unable to find new capacitors with a value of 6pF and 350V. (The existing one works, but it gets a bit hot and it sort of looks like it is swollen on the top and could potentially explode!) How can I find a suitable capacitor that will not damage the tube? The data sheet specs a value of 6pF and I can find other values (example 68uF 400V)?
I am a newbie in valve amps and can do with all the help I can get. My aim is to learn this way with an already working amp before I take on a project from scratch.
Many Thanks!
PS, I will post pictures if you need to look at it.
Jaco

[Alastair E]

Hmm.....

6pF cap would be tiny....

Is your cap tiny>

I suspect its a 6uF not pF

[WessieNC]

Hi Alastair, on the data sheet it says 6pF, and no, the cap is about 3 inches in length. Could it be a typo on the datasheet? The actual cap values is a bit faded out, so I can't really see what they are, so my only reliable source is the data sheet.(Which I downloaded from UL84 pdf, UL84 description, UL84 datasheets, UL84 view ::: ALLDATASHEET ::: )
Not sure if this is the best place to look for it?
Thank You

[quikie22]

a picture would go a long way in clarifying things up...

[DF96]

The only value on the datasheet which might look like 6pF and 350V would be an internal capacitance which is part of the valve, not an external component. Component values, perhaps given in an example circuit, would be much bigger: 6nF or 6uF for example.

[Golana]

the symbol for microfarad, can look like a "p".
The u has a tail on the left side. Then looking at an old document... easy to make that assumption of a "u".

[WessieNC]

Wow, I've learn't a lot from you guys so far! I will post pictures later today. (My camera is still charging...)
Looks like I am reading the datasheet all wrong - Thanks for pointing that out DF96 :-). So how do I determine the correct value for the capacitance? I don't want to damage the valves with the wrong values. (I am very cautious and don't like bang sounds!!)
The amp switch on and works, but with capacitors about 40 to 50 years old, I dont want to keep it on for to long.

[costis_n]

Considering the value and the (assumed) Push-Pull topology and the voltage, they are 6 μF (Note the use of Greek font).
Also considering that electrolytic caps were bulky and expensi9ve back then, It woud be very possible to swap them with something like 22μF/ 350V and get smoother Voltage.

[WessieNC]

Ok, now I am getting excited. I assume it is safe (don't worry, I wont blame anyone if it goes up in flames!) to replace the existing capacitors with something more modern, like a 22uF/350V cap, which brings me to my next question:
The current capacitor has 4 terminals.(Negative, 350,350,350). The new capacitors I can find with the 22uF/350V values only has Negative and Positive (2 terminals). Will it makes any difference if I just join the positives to the one terminal point on the new cap? (Pics will come up later still...)
Thanks guys (and girls?)

[boywonder]

Sounds like you have several caps in one can (a few pictures will go a long way). If so, there should be several uf values on the side of the can. 4 terminals usually indicate 3 caps and one common terminal.

Here are some modern versions:

Can Capacitors