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Old 23rd October 2010, 02:05 PM   #11
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C43: 470uF/6V3:
100uF is enough for sufficient low cutoff frequency; I use 100uF/63V about
Evox-Rifa | Passives | Capacitors | Aluminium | Axial 105C |PEG124MD310VQ
and 1uF/63V for bypass about
WIMA | Passives | Capacitors | Plastic Film | Metallised 100C |MKS4/1.0/250/10
If you have small loudspeakers (bookshelf) use only 1x, 2x or 3x10 uF unipolar foil cap, e.g. EPCOS about
Epcos | Passives | Capacitors | Plastic Film | Metallised 125C |B32523Q0106J
1uF for bypass now no longer necessary.

C31: 2,2uF: replace this unipolar elcap through foil type
Vishay | Passives | Capacitors | Plastic Film | Axial 110C |MKP1839522634HQ

Independend of the condition replace additional all elcaps arround the voltage regulators 7815 and 7915 through new versions, at best also through 63V types

Quote:
Originally Posted by lohk View Post
These are the infamous red roederstein caps - good sound but not for eternity.
This caps are very good known for its can decomposition, even by audio devices from Krell. If you are find this caps anywhere, you must still replace it through high quality versions and metal can enclosure, also in cases, where the outside condition seems to be good like the attached photos

Visit this website from Mr. Jens Both, if you want more information about the reasons of "bad caps"
http://www.elcap.de/index2.html
Attached Images
File Type: jpg roe22-40.jpg (19.1 KB, 227 views)
File Type: jpg roe 2009-0109-Roederstein 교체 002-1.jpg (174.9 KB, 224 views)

Last edited by tiefbassuebertr; 23rd October 2010 at 02:25 PM.
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Old 26th October 2010, 11:40 PM   #12
liquias is offline liquias  Israel
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@jamal,
I have several versions of cyrus two amps, in all of them this cap exists. I know I pulled the defective ones out of my amp, so I did have them originally. I would like to see (if its possible), the additional version of the schematic for the amp.

@tiefbassuebertr,
I changed the caps to the non-polar nichicon muse 470uF 16V.
I can't seem to find 470uF 6V non polar caps, from a good brand.
I tested polar elna cerafine 470uF 6.3V sounded very good but they get hot for some reason I can't understand right now. I measure no DC across them, and I don't know why they heat up.

I'll try and post more results and questions tomorrow.
Thanks guys!
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Old 26th October 2010, 11:56 PM   #13
jamal is offline jamal  Singapore
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hi Liqulias, the cyrus 2 schematic I refering to, is issue 2006. the whole service manual is copyright 1999. here are no 470uf 6v non polar capacitor on the feedback path. I intend to put 2 1000uf connected back to back to get a value of 500uf non -polar cap on my Cyrus 1.

Quote:
Originally Posted by liquias View Post
@jamal,
I have several versions of cyrus two amps, in all of them this cap exists. I know I pulled the defective ones out of my amp, so I did have them originally. I would like to see (if its possible), the additional version of the schematic for the amp.

@tiefbassuebertr,
I changed the caps to the non-polar nichicon muse 470uF 16V.
I can't seem to find 470uF 6V non polar caps, from a good brand.
I tested polar elna cerafine 470uF 6.3V sounded very good but they get hot for some reason I can't understand right now. I measure no DC across them, and I don't know why they heat up.

I'll try and post more results and questions tomorrow.
Thanks guys!

Last edited by jamal; 27th October 2010 at 12:24 AM.
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Old 27th October 2010, 07:12 AM   #14
liquias is offline liquias  Israel
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Mine are definitely older, can you please post the schematic ?
Do you need my versions ?
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Old 27th October 2010, 10:19 AM   #15
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Quote:
Originally Posted by liquias View Post
I changed the caps to the non-polar nichicon muse 470uF 16V.
I can't seem to find 470uF 6V non polar caps, from a good brand.
I tested polar elna cerafine 470uF 6.3V sounded very good but they get hot for some reason I can't understand right now. I measure no DC across them, and I don't know why they heat up.
avoid non polar caps with low voltage. Use 63V type. in reverse direction the voltage is still 1V by electrolytics independend of the nominal reading voltage on the device. Check other sources for hot spots on your PCB near the capacitor and check high frequency oscillation with your oscilloscope accross the cap.
Avoid caps "special made for audio" and use only high quality parts for professional applications.

Last edited by tiefbassuebertr; 27th October 2010 at 10:24 AM.
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Old 27th October 2010, 03:07 PM   #16
MRupp is offline MRupp  Germany
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Quote:
in reverse direction the voltage is still 1V by electrolytics independend of the nominal reading voltage on the device.
This is correct for polar electrolytics but non-polar electrolytics have the specified voltage in both directions (hence non-polar). I presume you wanted to say this but it did not come out clearly in your post.

Quote:
Use 63V type.
Why? Other than higher voltage electrolytics generally having better specs than lower voltage types there is still the issue of size (and often increased inductance). Any supporting points for exactly 63 Volts?
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Old 27th October 2010, 04:25 PM   #17
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Quote:
Originally Posted by MRupp View Post
This is correct for polar electrolytics but non-polar electrolytics have the specified voltage in both directions (hence non-polar). I presume you wanted to say this but it did not come out clearly in your post.

Why? Other than higher voltage electrolytics generally having better specs than lower voltage types there is still the issue of size (and often increased inductance). Any supporting points for exactly 63 Volts?
This is right. However - non polar caps I cannot recommend, because it needs to large space in case of high quality versions (e. g. Intertechnik "Elko glatt") or its ESR value is too bad. ELNA BP CERAFINE series e. g. is a bad choice. Actually internal two polar electrolytic caps are connected anti-serial by N.P. electrolytics (outside connectors neg. poles - as I know).
The reason for 63V types is the fact, that most brands only by this voltages reaches their lowest value for ESR both at dc and 10/100KHz. This I have heard from a developer. You can see also this in the data sheets by the ESR values by the various VDC values.
By few certainly models lowest ESR is to find at 50VDC or 100VDC, but mostly it is by 63VDC except various brandnew types for PC Motherboards e. g. from Sanyo; go for PDF download to
http://www.endrich.com/de/site.php/110
I don't know why it is just 63VDC Ask Mr. Jens Both - http://www.elcap.de/4437/index.html
read also this threads:
myths and facts on electrolytic capacitors in audio circuits
Best electrolytic capacitors
Better Audio by Solid State Amps after Coaching of certainly Electrolytic Caps ??

Last edited by tiefbassuebertr; 27th October 2010 at 04:45 PM.
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Old 27th October 2010, 05:22 PM   #18
MRupp is offline MRupp  Germany
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Well both polar and non polar electrolytics are internally two caps that are in series ("connected via the electrolytic"). The only difference is that in polar caps one aluminium foil is formatted so that the oxide layer grows thicker and withstands the rated voltage. The other is left unformatted and has only the natural thin oxide layer that forms on aluminium under atmospheric conditions and can withstand some 1.4 Volt or thereabouts (reverse voltage before breakdown). For non-polar caps the second foil is also formatted so that is has also a oxide layer thick thick enough for the rated voltage. This might actually explain why they are a bit bigger (or s I assume).

Non-polar caps still show much lower distortions as coupling caps, especially at lower frequencies, so that you will get away with much less capacitance compared to polar caps. So if you have to use a DC blocking cap in such a position the non-polar one may still be the better choice. The non-etched "glatte" caps are again much bigger so I doubt they would fit everywhere.

I do agree though that higher voltage caps have better ESR but I wonder if less voltage would still be "good enough" under most circumstances.

P.S. I just happen to have some old non-polar red roedersteins caps and are wondering if and how you can reformat non-polar caps (reformatting one foil might weaken the other, and vic versa). I will try your contact at Elko-Consulting to see if they have any info.
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Last edited by MRupp; 27th October 2010 at 05:26 PM.
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Old 28th October 2010, 08:07 AM   #19
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Quote:
Originally Posted by MRupp View Post
Well both polar and non polar electrolytics are internally two caps that are in series ("connected via the electrolytic"). The only difference is that in polar caps one aluminium foil is formatted so that the oxide layer grows thicker and withstands the rated voltage. The other is left unformatted and has only the natural thin oxide layer that forms on aluminium under atmospheric conditions and can withstand some 1.4 Volt or thereabouts (reverse voltage before breakdown). For non-polar caps the second foil is also formatted so that is has also a oxide layer thick thick enough for the rated voltage. This might actually explain why they are a bit bigger (or s I assume).

Non-polar caps still show much lower distortions as coupling caps, especially at lower frequencies, so that you will get away with much less capacitance compared to polar caps. So if you have to use a DC blocking cap in such a position the non-polar one may still be the better choice. The non-etched "glatte" caps are again much bigger so I doubt they would fit everywhere.

I do agree though that higher voltage caps have better ESR but I wonder if less voltage would still be "good enough" under most circumstances.

P.S. I just happen to have some old non-polar red roedersteins caps and are wondering if and how you can reformat non-polar caps (reformatting one foil might weaken the other, and vic versa). I will try your contact at Elko-Consulting to see if they have any info.
Interesting facts. I have also often heard, that non-polar caps should still have much lower distortions than polarized caps at lower frequencies.
Denon uses even polar caps in their baxandall-equalizer section of the "PMA-1560" (down to 100nF) - go to schemas by post #4 about
Denon's MOS "Super optical Class A" from PMA1560 - how works this circuit

Some other developers claim, that tantal caps as coupling caps in the signal pad are the best choice (in case of non symmetric power supplies). Naim Audio is an example. For me the question is, whether this views are really true. Never I have observed a confirmation for that by various listening tests. My experience is, that foil caps in signal pad is always better choice than electrolytics, even in such cases, where the occured unwanted high pass function (and the associated - for perfect stereo panorama unwanted phase shift/group delay time) arises to higher frequencies. An alternative is the use of high quality polarized caps (in case of non symmetric power supplies).
Completly dc coupled stages actually should be the royal way, but this is difficult to realize and any few developers claim, resistors (especially that one for NFB and gain determine) without voltage biased works sometimes like diodes with additional unwanted high-order THD.
So for me the royal way is unsymmetric power supply for audio circuits and either foil or polarized electrolytic caps arround 63V in the in this case naturally no dc coupled signal pad.

Last edited by tiefbassuebertr; 28th October 2010 at 08:15 AM.
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Old 12th October 2011, 05:22 PM   #20
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hi! liquias,

i had the same problem for my ver.7 cyrus 2 too! so how is the going after one year...
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