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Any Recommendation for 100uF Capacitors in Quad 34 pre amp welcome

HeinzR

pfm Member
I replaced the 33 year old electrolytic capacitors in my new to me 34 for all positions for precautionary reasons after I listened to it for several weeks with joy. In various forums as a replacement for the 100uF caps Elna Silmic2 were praised. So I bought them and except for the work of soldering it is not a big risk to invest a total of 7€. To be honest I find the sound a bit undynamic and clogged. Even all the blah blah with break-in time etc. does not change this basic impression at least until now after a week of playing. Even the ancient original caps sounded somehow more "natural". Perhaps I really have to „wait“ a little longer time to let them run in? Now I've read that the Nichicon elkos should sound very natural and open. But there are different types and not every type might be the best fit for the Quad 34. Also there are "bipolar" Nichicons among them but if I understand it correctly the Quad 34 needs unipolar caps in the position of the 100uF? BTW I know that some people recommend to bypass these caps at certain positions but I will stay „original“.

I'm not crazy about Nichicon, even if I can easily order them from Mouser but I also appreciate any other brand/type recommendations. I would be happy if experience and satisfaction can be shared here. To be honest I am not a fetishist who wants to hear the pin drop, It is easy to make me happy sonically but the Silmic2 are somehow not my taste, at least until this point of use.
 
Silmics have always sounded as you describe to me. I’d go for Nichicon Fine Gold types, KZ if you want a slightly more coloured sound (I prefer the cheaper FG types). Panasonic FC is a good alternative in all positions.
 
Silmics have always sounded as you describe to me. I’d go for Nichicon Fine Gold types, KZ if you want a slightly more coloured sound (I prefer the cheaper FG types). Panasonic FC is a good alternative in all positions.

Thanks for reply, do you really mean coloured which would not be my taste or do you mean colourful?
 
Silmics have always sounded as you describe to me. I’d go for Nichicon Fine Gold types, KZ if you want a slightly more coloured sound (I prefer the cheaper FG types). Panasonic FC is a good alternative in all positions.
John echoes my findings with Silmics, I just didn't like them in the signal or feedback path. I don't know much about the 34 I'm afraid.
 
Thanks for reply, do you really mean coloured which would not be my taste or do you mean colourful?

Well, without wading too far out into subjective waters again (I’ve lately been finding the objective shoreline more attractive recently!), I recall the KZ types were rather ‘Naim’ like, if you will. No surprise many use KZs to often recap the earlier classic models (bolt down, chrome bumper, olive). They have a fullsome bass, but just sounded a tad ‘hifi’ to me. The FGs just ‘sound’ more even-handed to me in terms of tonal colour. Gosh, I hope the ASR lot don’t see this post
 
Gosh, I hope the ASR lot don’t see this post

I had an academic paper somewhere with the measured distortion characteristics of different capacitors, showing their harmonic profiles. I think it covered about 40 different capacitors from cheap ceramics through to daft money PIO stuff. Much was different electrolytic though. Was all a bit mental, the guy had to make a crazy clean signal source first with a SNR of about 140-150dB!

If ASR catch up with you I will try and find it!
 
Normally I'm happy if I can just listen to my music for many years and not have to worry about parts replacement. In other words, the time of trying around with all kinds of parts like tubes, capacitors, cables etc. is long gone with me. But now the reason of swapping was prevention from possible later damage with such old e-caps.
When I read forums, it often does not get better because everyone has a different level of knowledge, taste and opinion. So I come to the following conclusion: Because it is a lucrative market, almost all capacitor manufacturers design so-called audio premium series and they also offer normal goods. The probability that I am somehow disappointed with these premium e-caps may be greater, because the manufacturer may want to put a special stamp on "his sound". There are ancient desires awakened ... "now sounds like a tube amplifier" etc. TBH I've been listening to C22CE along with MC275Mk4 for the last 20 years on one piece, which I like a lot.... I was just curious how today the combination Quad 34 with 306 sounds to my ears because I had these units 35 years ago. To my amazement I am more than impressed how good it sounds on both my SB LS3/6 and my 1977 LaScala. That was before I swapped the e-caps for Silmic2. And what did Quad use back then? Completely normal e-caps. At that time there was no market for "audiophile" capacitors. A short time later it started with the "Blackgate" e-caps, in the 90s?

So I will look for more or less ordinary e-caps. John_73, your tip for the FG is going in the right direction for me...solid decent e-caps, even if the even the FG are already called audio high grade, at least I will avoid exotics. The Silmic2 have been enough for me as a trip there. I want to hear music and instruments, but not an "improved sound" that gets on my nerves after a short time.
 
My two favorite for their natural and transparent sound are now the Nichicon KA and UPW.
I used a lot of Elna Silmic II in the past and still do but they make the bass a tad heavier and the treble a bit on the soft side, kind of tube-like IMO.
When the KA is not available, I use the Panasonic FC with similar results.
 
Hi Guys.

To be frank just go for any name branded electrolytic with a rating of 35V or more. Look for a LOW ESR type, with a 105 deg. C rating from a known manufacturer and save your money. The QUAD uses offset power rails of +8.6V / -9.4V to power the OpAmps so the CAPS will always have a DC voltage across them and there is no source of temperature stress inside the 34 preamp. If you get a 35V Rated caps (and 50V for the PSU Caps) they will be operating well inside their limits and they will last well past their rated life by a good many decades.

Call me cloth eared but I am yet to hear any difference between known branded capacitors that have been appropriately selected according to the application and are operating within their limits. Modern Electrolytic technology has come a long way since the 70’s and early 80’s. Modern capacitors, with the exception of the cheap Chinese copies, are capable of respectable performance. Look inside allot of modern upmarket Hifi gear and you will see many parts with names from component manufacturers based in the far east.

You can quite often do damage to an aging PCB by reheating solder pads just to experiment with different caps that can easily outweigh any real tangible benefit that might be gained.

Happy Listening

LPSpinner.
 
You can quite often do damage to an aging PCB by reheating solder pads just to experiment with different caps that can easily outweigh any real tangible benefit that might be gained.

LPSpinner.

If the cap is sufficiently raised from the pcb, clip the legs off and remove the legs one at a time with soldering iron and tweezers. After working on 80's Neve mixing desks I found repeated cycling of heat was often most likely to lead to lifted solder pads and tracks. If you can heat the pad and remove the leg in one hit rather than repeated heating and 'walking' the cap legs out, you are likely to do less board damage this way IMHO. A proper desoldering gun is even better and you can hoover the cut leg and excess solder out in one hit!

FWIW I have found Panasonic FC cap VERY reliable and long lasting, no complaints on sound to boot either.
 
Hi Guys.

To be frank just go for any name branded electrolytic with a rating of 35V or more. Look for a LOW ESR type, with a 105 deg. C rating from a known manufacturer and save your money. The QUAD uses offset power rails of +8.6V / -9.4V to power the OpAmps so the CAPS will always have a DC voltage across them and there is no source of temperature stress inside the 34 preamp. If you get a 35V Rated caps (and 50V for the PSU Caps) they will be operating well inside their limits and they will last well past their rated life by a good many decades.

Call me cloth eared but I am yet to hear any difference between known branded capacitors that have been appropriately selected according to the application and are operating within their limits. Modern Electrolytic technology has come a long way since the 70’s and early 80’s. Modern capacitors, with the exception of the cheap Chinese copies, are capable of respectable performance. Look inside allot of modern upmarket Hifi gear and you will see many parts with names from component manufacturers based in the far east.

You can quite often do damage to an aging PCB by reheating solder pads just to experiment with different caps that can easily outweigh any real tangible benefit that might be gained.

Happy Listening

LPSpinner.

Thank you very much, LPSpinner and also to all the others with your very valuable contributions. Do you know that now I feel much better with my decision, because I will order Panasonic e-caps. In addition, an observation about these caps in all kinds of forums posts around the world. Pretty much everyone shows their satisfaction and...voila, that's mostly all there is to say. In contrast, there is so much blather about Silmic2 or Muse or whatever other "audiophile" caps as if it were a red wine forum, talking about vintages, wineries, soil, grapes, tannin content, etc. I am so glad to have found a reliable and credible place here. Well...I started the thread by saying that I am dissatisfied with Simic2 in my specific application. It is perhaps like the fairy tale "the emperor's new clothes". If I had started a thread praising Silmic2 then most likely the "wine connoisseurs" would have spoken up.

One question, in the link is a Panasonic FR with 35V. All FC types and other FR with 50V are indefinitely out of stock at Mouser (where I always order, because from 50€ without shipping costs).
The Panasonic FR look quite decent according to the data sheet, low ESR, long life, 105C etc. I think the FR series is just newer? Is there anything against it?

https://www.mouser.de/c/passive-components/capacitors/aluminum-electrolytic-capacitors/aluminum-electrolytic-capacitors-radial-leaded/?capacitance=100 uF&m=Panasonic&product=Low ESR Electrolytic Capacitors&series=FR&termination style=Radial&voltage rating dc=35 VDC

You can even find comments on the net where a low ESR on e_caps is equated with a shrill sound. How do people get that idea? I personally know only one case where a higher ESR is beneficial, and that is in the xover of my very old 1977 Klipsch Lascala (softer "Q", intended over all impedance of the network, confirmed by Roy Delgado, chief developer).
Meanwhile I have seen in the net that Silmic2 in particular have a poor ESR that may contribute to the congested sound. This data I have found in a German article:

  • Elna Silmic II: (D)=0,0532 / (Phasenwinkel)=-86,9° / (ESR)=1,917 Ohm / Q=18,77
  • Nichicon UKZ: (D)=0,0287 / (Phasenwinkel)=-88,3° / (ESR)=0,971 Ohm /Q=34,83
  • Nichicon FG: (D)=0,0574 / (Phasenwinkel)=-86,7° / (ESR)=2,214 Ohm / Q=17,41
  • Panasonic FM: (D)=0,0395 / (Phasenwinkel)=-87,9° / (ESR)=1,409 Ohm / Q=25,23

Since there are people with "reasonable approach" in this thread, another question beyond the Quad 34. I had ordered for my two Quad 306 the PSU caps below in the link. I have not been "audiophile" oriented but I went by lifetime and temperature. Did I do something wrong or is everything ok? Sonically, everything is really good.

Thanks a lot for reading.

https://www.mouser.de/ProductDetail/KEMET/ALC80A562CC063?qs=T94vaHKWudSbqp8mWLAllw==&countrycode=DE&currencycode=EUR
 
Silmics sound spongy and soft to me. The most neutral capacitors I've tried are Nichicon UKW Standard for Audio. I found the Nichicon KZ to be a bit bright.
 
On my reel to reel recaps I have started using the NIchicon ES (Bipolar caps) in the signal path, they actually have a little more ESR than an FG but the sound is transparent and natural IMHO

Alan
 
make sure to short out the 100uf caps that are not needed, the dada revision manual specifies which ones,
i just rebuilt a 34 which i bought as 'working fine' which really didn't, (2 of the LED driving transistors partial short dragging down the psu rails! and tons of track corrosion!
so i didn't have a chance to listen pre-upgrade,
coincidentally i used as Alan did Nichicon Muse ES BP, bright green! they sound great to me and should last well.
i went bipolar, as there is a lot of debate about which direction the polar ones should be, general consensus being Quad got it wrong for a couple of positions C16/17. also the polarity can change if you change the opamps types. and often is just a few mv.
I also upgraded the 4066 IC's to the MAX4066 which are technically better, again no A/B comparison possible for me.. well as i fitted sockets I could switch back but i'm likely too lazy to do that anytime soon.
 
Silmics sound spongy and soft to me. The most neutral capacitors I've tried are Nichicon UKW Standard for Audio. I found the Nichicon KZ to be a bit bright.
Certainly as feedback caps in Naim ccts the Silimics never sounded anything but muffled to me. For power supply caps on Naim boards Sanyo SPs have not been beaten in my listening.
 
make sure to short out the 100uf caps that are not needed, the dada revision manual specifies which ones,
i just rebuilt a 34 which i bought as 'working fine' which really didn't, (2 of the LED driving transistors partial short dragging down the psu rails! and tons of track corrosion!
so i didn't have a chance to listen pre-upgrade,
coincidentally i used as Alan did Nichicon Muse ES BP, bright green! they sound great to me and should last well.
i went bipolar, as there is a lot of debate about which direction the polar ones should be, general consensus being Quad got it wrong for a couple of positions C16/17. also the polarity can change if you change the opamps types. and often is just a few mv.
I also upgraded the 4066 IC's to the MAX4066 which are technically better, again no A/B comparison possible for me.. well as i fitted sockets I could switch back but i'm likely too lazy to do that anytime soon.

Grog, thank you very much for your eloquent input. I know the Dada site and that of Keith Snook. BTW Keith was so kind and calculated R1, R2 and C1 for my Quad 306 in case I would change it to 1,25V input sensitivity.
My 34 has the latest board, I think, No 7 with the orange Quad logo. TBH I wanted to leave everything original so far, also because I am experienced with normal parts soldering but not with op-amp soldering.
I also wanted to keep all e-caps in place. When I put in this boring Silmic2 two weeks ago I had changed polarity of C16 and C17 as Keith Snook has detected, described on his site (and Dada took over his knowledge).
So, for a later round I could follow your recommendation to short the caps in question but for now I will keep them in. I also was wondering if bipolar caps would work in place of the original polarized ones, obviously i goes very well in your 34. So far many people have their personal choices and recommendations regarding caps, I really have to think about it. Anyway, most if not all alternatives seem to be good if higher voltage and 105 C, at least all may be less boring than Silmic2 to my ears. I was thinking about Panasonic FM,FC or FR. FM are often recommended in the web but the newer FR are lasting four times as long, up to 8000 h. I don‘t know…at least all of your recommendations regarding standard caps are better than 1985 e-caps. Thanks for reading.
 
Cap choices is a bit of a slippery slope, as there's "always" something "better", and on forums - as here - everyone has their opinion towards what works best. A good way to side-step it all is sometimes to just send it off to Quad and get an 'official' service done, then leave well alone and just enjoy the music, and forget about caps :)
 
I would like to come back to the topic of Silmic2. It will take a while until my order of new capacitors arrive here and are finally installed. This has caused me to listen to these Silmic2 longer than desirable. One thing I can say right now, I do not get used to their performance. This is different from many other changes that someone can easily adapt over a few weeks. I am a proponent of measurement and I am convinced that the acoustic effects I find irritating on the Silmic2 could be measurable. It's not just the fuzzy floppy sound in terms of a static effect. I have a suspicion that the Silmic2s change their properties depending on the volume (voltage). The quieter the parts of acoustic information are in a piece of music, the more they are swallowed up, also in terms of treble reproduction. The quieter parts have less treble, only the louder parts reach the higher frequencies. I am convinced that this can be measured. Likewise, it should be measurable how much information is lost in the mids in the quieter passages. In summary, I think it is a dynamically changing and therefore very disturbing fogging of the sound.
 


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