Comparing modern electrolytic caps

[HiFiNutNut]

I have subjectively compared different values / voltages / ESR / ESL of capacitors in my line level, correctly implemented (no resonance, etc) circuits in my very revealing system and found the following:


Panasonic FC:

They have clear and clean sound with a bit of "hands cupping the mouth" type of sound. The low frequency is awesome. The very high frequency is exaggerated a bit.


Rubycon ZL:

Bass is not as strong as the Panasonic but very clean. They are the clearest, cleanest, fastest, most musical caps by far within a large range of the audio bandwidth, however, with a terrible problem causing me to basically abandon the use of these caps - they have a very picky treble that appears to be caused by resonances that can not be completely corrected using filters. Rolling off the treble does not help.


Elna Silmic (and many other Elna audiophile caps):

They do not sound "bad" but with very strong colorations. They seem to add rich harmonics to the sound. Solid state sound was made "tube" like. It is not my cup of tea.


Xicon (General Purpose):

They are higher ESR / ESL type but with an overall tonal balance. However, they do not have the ultimate refinement in sound.



Now I am in despair! I am thinking about using Panasonic FC throughout then alter my passive XO to adjust!

Have you guys found any other caps (low ESR / ESL or not) that sound balanced without major colorations / distortions?


Regards,
Bill

[AndrewT]

Hi,
where are these electrolytics fitted?
Decoupling/bypass or audio pass through/coupling or NFB loop or PSU/smoothing?

[HiFiNutNut]

Signal path is one but I had a great surprise - the cap that bypasses the adjustment pin of the LM317/337, although what the regulator powers up are OPA627s that are claimed to have 120dB rejection. According to the datasheet, a 10uF will do but put on a 470uF and be ready for the dramatical improvement on sound quality.

I can't explain in theory but go and try it one will find the difference bigger than changing a power amp.

This is easily a good tip for the tweakers.

I guess it has got to do with DF, etc, but perhaps more importantly with the internal variations in the ESR at low frequencies and ESL at high frequencies, as well as internal resonances, etc.

I have tested many caps in the past 2 weeks and continuously for 3 days in the past long weekend.

I have not found the ideal cap.

[Conrad Hoffman]

I think you'll find the OPA627 doesn't have anywhere near that rejection at high frequencies, nor does any other opamp. If you put a large cap on the reg adjustment pin, you should use protection diodes per the app notes. Most people use about 240 ohms for the top resistor because that's what the app note shows, and because under many conditions it gives the reg enough idle current to function within nothing attached. There's no law that says you can't scale the resistors up a bit, making the adjustment bypass cap that much more effective. It's also desirable to use a large output cap with significant ESR, or even a series resistor, thus preventing a high frequency noise peak. A small output cap with low ESR, like a film, can result in a rather remarkable noise spectra from those regs, and the peak can be right in the upper audio range.

[Curmudgeon]

The Nichicon Muse electrolytics (4 lines I think?) have gotten good sonic reviews. Blackgate are also worth trying.

I trust you're breaking them in before trying to evaluate... I use 40 hours as a rule of thumb, but it's only that. More or less time may be needed... Were the Rubycons fully run in?

[analog_sa]

Originally posted by HiFiNutNut

Rubycon ZL:

Bass is not as strong as the Panasonic but very clean. They are the clearest, cleanest, fastest, most musical caps by far within a large range of the audio bandwidth, however, with a terrible problem causing me to basically abandon the use of these caps - they have a very picky treble that appears to be caused by resonances that can not be completely corrected using filters. Rolling off the treble does not help.

This description fits BG standard prior to break-in very well. Curmudgeon has a very good point.

[Geek]

Hi,

Thank you very much for this information. Stuff like this is a LOT more useful, IMO, than charts and graphs from the mfr.

Originally posted by HiFiNutNut

Rubycon ZL:

..... they have a very picky treble that appears to be caused by resonances that can not be completely corrected using filters. Rolling off the treble does not help.

These are nasty in the treble because they are inaccurate.

I personally have found that bridging these with a 1uF or 2.2uF poly-anything (zillion dollar cap not needed here) cleans the treble up.

Keep up the awesome work!

[samoloko]

did anyone used panasonic FM

[danny_66]

Here's a recent test made by dorkus, he tested the pana FC, FM, Silmic II, BG-N and Wima MKP10:
http://diyhifi.org/forums/viewtopic....t=985&start=62
Strange is his observation about the Silmic II, quite the opposite of yours.
Probably it's all about where the caps are you used (coupling-decoupling) and how the rest of your audio gear sounds.

[Calvin]

Hi,

nothing against subjective evaluation but may I kindly ask what is meant by

correctly implemented (no resonance, etc)

and how You prooved it? Were there any paralleled caps or just the electrolytics? How about the inductance of PS-traces, etc. etc.
Without knowing where a C is located in a circuit, changing to a different cap the evaluation can only be subjective and hence general statements about the sonic character are rather meaningless. Slightest changes in the setup could lead to totally different impressions. In bad cases it leads even to a malfunction of the circuit by ringing, or becoming noisy. Especially ´fast´ OP-amps tend to be critical with the quality of the power suply. Its not for nothing that Op-amp manufacturers suggest that the PS-lines should be clean over the complete bandwidth of the OP. A point which You can´t fulfill with just a single blocking electrolytic somewhere.
Conrad already made some remarks about the whys and hows.
My experience with the ZLs are only very positive when implemented correctly and in the right position.

jauu
Calvin