c0g/np0 tdk 6pf 0603 TDK
http://il.farnell.com/tdk/cga3e2c0g1h060d080aa/cap-mlcc-c0g-np0-6pf-50v-0603/dp/2435458
http://il.farnell.com/tdk/cga3e2c0g1h060d080aa/cap-mlcc-c0g-np0-6pf-50v-0603/dp/2435458
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What is the purpose of the caps? Ceramic may be the best for the intended purpose. NP0 or COG ceramic if you want something very stable. The main downside with COG is that they are bigger than X7R but I doubt that is going to be an issue with 6pf!
The only polyprop I knew of that might come close was the wima FKP's but the smallest is 33pF.
edit: dazz beat me to it
Tony.
The only polyprop I knew of that might come close was the wima FKP's but the smallest is 33pF.
edit: dazz beat me to it
Tony.
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Why would you want to replace a 6pF ceramic (almost certainly a C0G/NP0) with polyester or polypro? First this could be a minor step down in dielectric quality. Second they probably don't make such small values with plastic dielectrics. Why do a 're-cap' at all?
What ever you do, don't change any caps in the RF or IF sections. 'Re-capping' the audio probably won't do much harm (but not much good either); 're-capping' the RF can almost certainly guarantee that it will no longer work properly, and I stronly suspect that you don't have the knowledge and equipment to repair and re-align it afterwards.
A 6pF cap is almost certainly in the VHF front-end so I hope you have not already ruined it.
What ever you do, don't change any caps in the RF or IF sections. 'Re-capping' the audio probably won't do much harm (but not much good either); 're-capping' the RF can almost certainly guarantee that it will no longer work properly, and I stronly suspect that you don't have the knowledge and equipment to repair and re-align it afterwards.
A 6pF cap is almost certainly in the VHF front-end so I hope you have not already ruined it.
Thanks for the responses.
The CR-800 is a circa 1973 receiver that has many ceramics in the power amp stage. Many are standard 104,151 with a scattering of 22,6.
I'm not replacing ceramics in the RF stage, just leaving that for the time being, but I'll look at replacing the 40 year old electrolytic.
The CR-800 is a circa 1973 receiver that has many ceramics in the power amp stage. Many are standard 104,151 with a scattering of 22,6.
I'm not replacing ceramics in the RF stage, just leaving that for the time being, but I'll look at replacing the 40 year old electrolytic.
I see where you are coming from, the 6pf is in the signal path (quite early on).
I don't usually change ceramics but I guess I'm a 'victim' of forum advice ie. the ceramics adding to the fizzy treble nature of this receiver. I'm prepared to give it a go but would value the thoughts of others before giving it a go.
DigiKey carries leaded NP0/C0G 6pF from Murata and TDK. Swapping them with polyester is a downgrade. Polypropylene don't come with these values in 50V rating. NP0 and C0G are the only choice and they are very stable parts.
RS UK carries Vishay radial 1kV C0G/NP0 5p6 and 6p8.
Best to leave the current 6pF in place. If you have an LCR meter which displays dissipation factor (DF), you can check if the current parts are NP0/C0G. This type has lower DF than X7R or Y5V. Does the current part have a solid paint color on the top? If yes then those are NP0s, common practice back in the days to indicate NP0s.
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Quite early on in the power amp? Sounds like an RF decoupling and/or stability compensation.
Most probably not literally in the signal path - it's impedance is way too high to pass audio.
Is this a tube or solid state amp (don't remember if you said that already).
Jan
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