[WireNut]

Hi, I am trying to upgrade the 2.0uf / 250volt caps in my preamp.
I have looked at many cap manufacturers and I am only finding values of 1.5uf, 1.8uf or 2.2 uf rated at 600volts.
Since I can't find the exact value of 2.0uf, what is my best option of the above values.

Thanks,
Steve

 

[avahifi]

I suggest you simply go ahead and use 2.2uF caps of the proper voltage and construction.  Note that typically film capacitors have a 10 percent tolerance, so that 2.2 uF cap will actually be somewhere between 1.98 and 2.42 uF in value.  The real secret is to match the capacitors channel to channel so that both channels will have the same characteristics as closely as possible.  This will require a reasonable stockpile of the needed capacitors, and a capacitor meter to find matching values.

The small difference in value between the stock 2 uF caps and 2.2uF caps will be negligible in sonic performance (unless they are being used in some critical timing circuit) as long as they are matched channel to channel.
Regards,

Frank Van Alstine

[medium jim]

I suggest you simply go ahead and use 2.2uF caps of the proper voltage and construction.  Note that typically film capacitors have a 10 percent tolerance, so that 2.2 uF cap will actually be somewhere between 1.98 and 2.42 uF in value.  The real secret is to match the capacitors channel to channel so that both channels will have the same characteristics as closely as possible.  This will require a reasonable stockpile of the needed capacitors, and a capacitor meter to find matching values.

The small difference in value between the stock 2 uF caps and 2.2uF caps will be negligible in sonic performance (unless they are being used in some critical timing circuit) as long as they are matched channel to channel.
Regards,

Frank Van Alstine

That is so true....added thought, the higher the capacitance, the warmer or darker the tone and visa versa.  So if you want a brighter tone, go with lower values, i.e., 1.8uf and for darker/warmer, go with a 2.4uf.   

Jim

[richidoo]

If they are output coupling caps, then the larger value the better to minimize low frequency rolloff. The rolloff frequency depends on the cap value and the input impedance of the connected amplifier.

http://www.v-cap.com/coupling-capacitor-calculator.php

Of course, larger caps are expensive, so the larger is not always better.