C2 Input Coupling Cap

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07-Nov-2017 11:00 AM

CBK

CBK

Posts: 27

In regards to replacing the C2 input cap, someone mentioned it's not a good idea to use a cap that is physically LARGER than the original (due to HF instability and oscillation ect). 

Is problem of using a larger cap because of "physical size", or is the problem using "higher values" (or both?). 

I would like to keep the original stock value of 330nF, but the polypropylene I found is physically a bit larger (7mm taller in height).

Thoughts anyone?

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07-Nov-2017 06:00 PM

Joost Plugge

Joost Plugge

Posts: 938

I assume you are talking about a 606MKII, 707 or 909. I never had those problems, I use normal polyester caps or Panasonic polypropylene, the brown candy like ones. In theory it is possible to pick up signals on any metal object that act as a antenna, but inside a closed cabinet? There is a lot of fake news around! Did you or anybody else for that matter think that Quad selected their capacitors for size? My guess; prize was the most important criteria.

Joost Plugge

DaDa Engineering

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09-Nov-2017 08:50 AM

CBK

CBK

Posts: 27

Yes for the 606/909.

Which Panasonic polypropylene do you use? Is it available in your webshop?

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13-Nov-2017 11:40 AM

Joost Plugge

Joost Plugge

Posts: 938

No, not at this moment.

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13-Nov-2017 12:17 PM

CBK

CBK

Posts: 27

If i raise the value of C2 to 470nF, can this cause some high frequency information to be lost or cut off?

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14-Nov-2017 12:01 AM

EJP

EJP

Posts: 1405

No, how could it do that? It has less impedance at higher frequencies, not more.
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