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I was told that I could remove the input caps from my amp since my preamp already has output caps.
If I remove the amp input caps, what should I put in place, one resistor in place of each cap? or should I just short the unconnected terminals?
Thanks!
Follow Ups:
As others have said, you need to check the design of the amp and preamp to know how to proceed.
In most solid state power amps that I have worked on the input is at ground potential and the input cap is not necessary. The prevalence of the input cap is to minimize damage to the power amp and/or loudspeakers due to a preamp fault.
The output cap in the preamp is more likely to be required due to DC voltage at the output of the preamp. This depends on design.
You can easily replace the caps with a higher quality part. Use film types if space permits. If you are forced to stay with electrolytic caps due to space constraints try tantalum types, they sound better that typical aluminum types.
Hi.
If there is a volume control in the power amp & the I/P coupling cap hooked up directly to the volume pot. Chances are you can bypass it.
But if there is no volume control in your amp & the I/P cap is (usually) hooked up direct to the I/P terminal of the SS device where DC bias exists, don't be a smart ass to bypass it. This will upset the DC bias of the I/P SS device, say a bi-polar transistor, & cause distortion.
The I/P coupling cap also serves as DC blocker against any DC offset flowing into the power amp from the preceeding component.
For most transistor power amps, the I/P coupling cap also serves as a subsonic low frequency filter & helps to stabilize the entire direct coupling operation of the power amp. Removing it can cause transient
instability of the power amp, resulting possble blowing the power amp.
Why you want to bypass the I/P cap anyway?
c-J
There is no volume control in the amp.
I was told that the input caps in the amp could be redundant since my preamp already had output caps. And since the best cap is supposed to be "no cap" I thought it could be a good approach removing a pair of them.
But it seems that it might not be a good idea based on the input here.
Thank you all for your comments.
IMO it is much safer to leave the amp caps there and remove the preamp caps, if you must. A wire link to replace them.
With no input caps, any mixup with cables etc can cause catastrophic overload to amp and speakers. This very much depends on lots of other things, of course, but it is an accident waiting to happen unless you are VERY careful.
Removing the preamps's coupling caps is a really bad idea. If the preamp is a tube preamp you will be placing several hundred volts at the amps input cap which is typically only a 16v rated cap. Also if the preamp has a shorting output mute you will then place that high voltage on the mute contacts. The minimum that will happen is a loud pop through the speakers, the worst case is blown amp, speakers.
Even if the preamp is solid state, there could be dc in excess of 50V before it's coupling cap. Damage will occur.
Leave both caps in place.
If you are looking for a better compromise solution, replace the amps input cap with a Bi-Polar cap. Amps usually have an electrolytic at the input. E-caps are not too linear unless there is good dc voltage on them. Bi-polars get around this and work very well as amp input coupling caps.
Black Gate, Panasonic and others make very good ones.
DTS
Many SS amps are DC coupled and this would leave you wide open to pumping a huge DC signal into your speakers. :( I have done this once, the speakers do not survive. Hook that preamp up to a subwoofer amp that is DC coupled and kiss the driver goodbye. I would leave the input and output caps on the amp and preamp respectively.
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