• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Help me to make tube amply

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hienphs

Member
2010-10-25 9:25 am
Dear everybody,

I have a pair of capacitor:

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.

So I want to DIY amply with :
Input Power : 110v
Power : 65 watts x 2 in ultra-linear mode 30watts x 2 for triode mode
Output Tube : Power Tube adopts Shuguang KT88x 4
Input/Driver Tube : 12AT7 x 2, 12AU7 x 2
Ohms : 4 ohms and 8 ohms
I wanted to know this capacitor suit for this amply or not
Thank for your advise
 

kevinkr

Administrator
Paid Member
I'm not sure there is any reason you couldn't use them if you wanted to - mounting would be the biggest concern. They could be very interesting, but would seem better suited to an SE amp with 0 fdbk where they would be audible.

100nF is big enough to be quite useful and there is no better dielectric IMHO than a vacuum. Could be very good.

I'm actually intrigued - where did you get these, and if you don't mind my asking - were they expensive?
 

kevinkr

Administrator
Paid Member
Definitely not. What you have there are capacitors for an RF amp. The capacitances are going to be way too small for any audio frequency application. If you're not going to do an RF project, you can e-bay them to help fund an audio project.

I guess these might actually be 100pF capacitors and not 100nF caps as some have supposed - in which case they are not suitable as Miles has indicated.
 
This is a vacuum capacitor and its value is 100pF (cyrillic ПФ = PF) but beware, the tolerance is pretty large at 10%.

There is no reason it cannot be used in an amplifier if 100pF is needed somewhere. After all, a vacuum capacitor has the most perfect dielectric known to man :) But the problem is, 100pF is not a common value for audio applications.

Thus I agree it could be put to better use if it would pass to somebody who is into transmitters, like a radio amateur. With the money you can make, you could buy better output transformers. That would make more of a difference sound-wise.

Kenneth
 
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