| argo |
I am sorry if this has been already covered somewhere in the forum just couldnt find it during the quick search.
Is it OK to use one section of the power supply multi-section capacitor for cathode bypass or would it cause a problems?
If it's a bad idea, what type of separate capacitor would you recommend instead (except Black Gate) - some film cap like Solen metalized polyprop or just a decent electrolytic.
Thanks in ahead,
Argo |
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| Sch3mat1c |
It's been done in the past. Unfortunately, they also sucked on the value, using for instance 20uF across a 250 ohm cathode bias resistor - what the heck good is that!
As long as the capacitance is sufficient and voltage rating in range, it's fine. (Caps like to be ran near rated voltage, otherwise they degrade and capacitance changes. This can be temporarily (i.e., <5 years) recovered by reforming. Using a 450V rated cap at 20V is not using your brain or resources.)
Tim |
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| argo |
Thanks for the input.
I was thinking to use the free section of 220+220uF/500V Elna Cerafine PS cap. I didn’t thought about too high voltage rating though. Hmm, interesting point.
I was more worried about the common negative terminal of the multisection caps. As if one section will be used for PS smoothing and other section used for signal, probably both, very high and dirty currents and signal will flow through the same negative terminal tied to ground and will be mixed which could degrade the sound? |
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| SY |
| The ground currents could be an issue for an SE amp- a push-pull amp will have decent common mode rejection at the cathode. But if the lead to ground is short and thick, you're unlikely to have a problem. |
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| Sch3mat1c |
If you star ground to the ground terminal of the capacitor, the only place that can develop a voltage is the terminal between the star and the capacitor itself. Not a problem.
Tim |
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| resident |
| quote: | | Using a 450V rated cap at 20V is not using your brain or resources |
Oooou. I have done that in a cathode bypass cap!I have bypassed an electrolytic cap,range at 50V, with a MKP range at 400V.Is this wrong?How can I bypass an electrolytic cap at 470uF if I can't find a MKP at 4.7uF/50V? |
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| fdegrove |
Hi,
| quote: | | with a MKP range at 400V.Is this wrong?How can I bypass an electrolytic cap at 470uF if I can't find a MKP at 4.7uF/50V? |
With filmcpas this isn't a problem.....
You can find 63VDC filmcaps though.
Cheers,;) |
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| resident |
Where can I find 4.7uF/63V MKP?
Until now I was using Audyn MKP at 400V to bypass the electrolytics at small voltages. |
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| fdegrove |
Hi,
| quote: | | Where can I find 4.7uF/63V MKP? |
Not sure about MKP but any dealer carrying WIMA or Roederstein
filmcaps should have them in MKS or MKC @ 63VDC.
The lowest voltage MKP cap I have in my parts bin is 100VDC one.
The values should go up to about 10µF in these voltages and films.
Cheers, ;) |
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| resident |
Hmmm....yes I know those Wima and Roederstein.I haven't use them because they're not MKP.And I believe that they're not so good as Audyn MKP are.
Are they? :confused:
Do you know the differences btw MKP,MKS and MKC? |
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| fdegrove |
Hi,
| quote: | | Do you know the differences btw MKP,MKS and MKC? |
Basically, in order of lower dielectric absorption:
1/ MKP 2/MKC 3/MKS
1/ Metallized polypropylene film
2/ polycarbonate (no longer manufatured, I think)
3/ polyester
You can find all the technical information here:
WIMA TECH PAPERS
Neither may be as good as the Audyn caps but for bypassing an electrolytic cap used as a cathode bypass the smaller size of the lower voltage caps is certainly more practical.
Cheers, ;) |
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| resident |
| quote: | | but for bypassing an electrolytic cap used as a cathode bypass the smaller size of the lower voltage caps is certainly more practical. |
Yup I agree with that.
I don't now how to put them right now in my new preamp. :D
Thanks for the link and information. |
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| skyraider |
| other than those stupid BG for cathodes, is there any other better makes that is cheaper? |
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| resident |
Elna Cerafine are very good or Panasonic FC series.
I'm using Nippon Chemicon :smash: bypassed with Audyn MKP or Mundorf MKP. |
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| DigitalJunkie |
| I've heard that the Sanyo Os-Con's are a decent sounding cap,anyone here ever try them? |
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| skyraider |
| I am using os-con on the cathodes for my 12B4a linestage. However, I cannot confirm the sound yet because I have not been testing it with other caps. |
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