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The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


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Roy Mottram
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    Capacitor and sound quality

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    Sprags


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    Capacitor and sound quality Empty Capacitor and sound quality

    Post by Sprags Thu May 23, 2013 4:53 pm

    Excuse my lack of knowledge but can someone please tell me how different capacitors in amps and preamps affect or change the quality of sound.
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    Post by corndog71 Thu May 23, 2013 6:11 pm

    Well, here's Clarity Cap's response.

    http://www.partsconnexion.com/t/claritycap/Reseach_Summary.pdf

    Basically, it's caused by the materials used in the construction as well as geometry of the cap. Different materials affect the signal differently. And not every cap is made with the same materials.
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    Sprags


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    Post by Sprags Thu May 23, 2013 8:03 pm

    Ok...I read the article..can someone tell me why using the Russian K40-PIO and power supply capacitor upgrade helps improve the sound quality?
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    stewdan


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    Post by stewdan Thu May 23, 2013 9:04 pm

    Hi --- The science of capacitor design has advanced greatly in the last 50 to 60 years.

    If you are upgrading a 50 year old amplifier with modern power supply capacitors (say the quad cap) the amp is now able to store more electrical energy which provides smoother transient power when needed. The smoother power translates to our ears as "sounds better". (I guess there is less stress in the sound)

    Russian K40Y Paper in Oil Caps are not a new design but when used as coupling caps in an dynaco amplifier or equivalent provide a clean neutral sound which our ears again pick up as "sounds better". Perhaps the greatest reason for using the K40Yers is that they are usually less than $10 apiece as opposed to the "better sounding $100 caps".

    I am sure there are other explanations that are just as valid. If you do a Search on the Forum for "capacitors", I am sure something will pop out, since there has been lots of capacitor discussion.

    Have fun!

    Bob Latino
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    Post by Bob Latino Thu May 23, 2013 9:53 pm

    Sprags wrote:Ok...I read the article..can someone tell me why using the Russian K40-PIO and power supply capacitor upgrade helps improve the sound quality?


    Hi Blake,

    1. The power supply upgrade caps ... The upgrade caps are larger and have a lower ESR (equivalent series resistance) than the stock caps. With a lower ESR, these Nichicon (Made in Japan) capacitors discharge and recharge at a quicker rate making the amp more able to keep up with the changing musical signal. The larger values also give more "headroom" to the driver circuit when playing at higher volume levels.

    2. The Russian PIO main coupling capacitors. These capacitors are very important because all 4 caps are directly in the signal path. It is the job or each Russian PIO cap to pass the audio signal from the driver circuit to each of the 4 output tubes. You want to pass this audio signal with as little "alteration" of the signal as possible. These military grade caps do the job very well and don't really "intrude" or add their own sonic signature to the music. I am not saying that the Russian PIO caps are the BEST coupling caps ever made but their performance to cost ratio is very high. You would have to spend probably 5 times their cost to give even a perceptable increase in sound quality. I had a customer one time who built a pair of VTA M-125 monoblocks ask for 4 EXTRA Russian PIO caps to "try" in his very expensive Audio Reaserch tube amp. Once he put them in his Audio Research amp he liked the improvement in the sound of his AR amp and kept them in that amp.

    Bob

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    Sprags


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    Post by Sprags Thu May 23, 2013 10:06 pm

    Thanks for all the input. It's helping me understand.as I said I'm new to learning about electronics.

    I bought the book 'Valve Amplifiers' by Morgan Jones and everything in it was foreign to me. I ended up needing some tubes and interconnects and found out Parts Express is about 15 minutes north of where I live and when I was there I found the book 'Beginner's Guide to Tube Audio Design'. That's helped a little more but I think I need something even more basic.

    But since reading I've come to understand what basic components do...I just didn't understand how the differents help make audio equipment sound better.

    Thanks again...Blake



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    stsk


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    Capacitor and sound quality Empty Jung and Marsh

    Post by stsk Thu May 23, 2013 10:11 pm

    A classic pair of articles from Jung and Marsh:
    http://www.scribd.com/doc/24913258/Picking-Capacitors
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    Post by DarthBubba Fri May 24, 2013 3:20 pm

    stsk wrote:A classic pair of articles from Jung and Marsh:
    http://www.scribd.com/doc/24913258/Picking-Capacitors

    Yup, that was the article that pretty much started it all. A few audiophiles sort of knew about cap differences, but there was no real seminal article before that one that was readily available at the time.

    Anyway; has anyone compared the K40Y-9 (silver metal case) caps to the K42Y-2 (green outer case) caps soundwise - both types in the same location of the amp or preamp, same capacitance value, etc?
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    Post by harpy Sat May 25, 2013 3:41 pm

    Don't want to jack the thread, but what about Russian Teflon FT-3 as coupling caps? I shrink tubed one, but notice it had vent holes. Can you block the vents?

    Capacitor and sound quality DSC_1650_zpsdfe34c1c

    Running the K40's on a Mk III's with a stock circuit at present.
    Bob Latino
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    Post by Bob Latino Sat May 25, 2013 3:47 pm

    harpy wrote: Don't want to jack the thread, but what about Russian Teflon FT-3 as coupling caps? I shrink tubed one, but notice it had vent holes. Can you block the vents?

    Capacitor and sound quality DSC_1650_zpsdfe34c1c

    Running the K40's on a Mk III's with a stock circuit at present.

    The Russian FT-3 caps are nice but a little too large for many places like coupling caps on the VTA driver board. In applications where you have a lot of space they would be good choices ...

    Bob
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    Post by arledgsc Sun Jun 09, 2013 1:31 pm

    Excuse my lack of knowledge but can someone please tell me how different capacitors in amps and preamps affect or change the quality of sound.
    In a minimal circuit designs like in the Dynaco amps component selection can have a large, direct influence upon the sound of the amp. For instance in the ST-120 the 0.1uF preamp coupling capacitor and the two 0.15uF phase inverter couplers directly carry the audio signal from one stage to the next. If these capacitors distort or add undesirable coloration to the signal you will notice it readily. Along those same lines capacitor characteristics can be used to tune the sound as well. These two signal cap locations though influence the sound in the same way different tubes sound in the amp. There is no one holy grail cap that satisfies everyone or every system. Your ears and taste will help settle what you prefer.

    The power supply capacitors don't directly carry the audio signal but have an indirect influence upon sound quality. If the power supply is noisy or under-filtered you will notice that as well. Low ESR electrolytics provide an easier path to ground for things you want to filter like noise and AC ripple. Plus the additional capacitance in the electrolytic upgrades help hold up the B+ voltage on high transient current demands resulting in lower distortion audio. Both of Bob's capacitor upgrades are highly recommended. They are great affordable changes that benefit the sound quality over stock components.
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    Post by 45scratches Sun Apr 16, 2023 10:45 pm

    Bob Latino wrote:
    Sprags wrote:Ok...I read the article..can someone tell me why using the Russian K40-PIO and power supply capacitor upgrade helps improve the sound quality?


    Hi Blake,

    1. The power supply upgrade caps ... The upgrade caps are larger and have a lower ESR (equivalent series resistance) than the stock caps. With a lower ESR, these Nichicon (Made in Japan) capacitors discharge and recharge at a quicker rate making the amp more able to keep up with the changing musical signal. The larger values also give more "headroom" to the driver circuit when playing at higher volume levels.

    2. The Russian PIO main coupling capacitors. These capacitors are very important because all 4 caps are directly in the signal path. It is the job or each Russian PIO cap to pass the audio signal from the driver circuit to each of the 4 output tubes. You want to pass this audio signal with as little "alteration" of the signal as possible. These military grade caps do the job very well and don't really "intrude" or add their own sonic signature to the music. I am not saying that the Russian PIO caps are the BEST coupling caps ever made but their performance to cost ratio is very high. You would have to spend probably 5 times their cost to give even a perceptable increase in sound quality. I had a customer one time who built a pair of VTA M-125 monoblocks ask for 4 EXTRA Russian PIO caps to "try" in his very expensive Audio Reaserch tube amp. Once he put them in his Audio Research amp he liked the improvement in the sound of his AR amp and kept them in that amp.

    Bob

    You told me the secret sauce on the caps to replace in my Dynaco PAS-4 from the nineties, which I did do and found it to be a GREAT improvement. The replacement capacitors were Mundorf Silver Gold of some sort (dont recall) and the board position for them was C9 and C109 as found here in the manual https://www.thetubestore.com/lib/thetubestore/schematics/Dynaco/Dynaco-PAS-4-Schematic-Owners-Manual.pdf

    I was wondering if this capacitor choice was a good one for this application in your opinion. Are there other capacitors that would be in the direct signal path worth looking at? I was also curious if the PIO capacitors that I got in my st120 kit would work in the C9 and C109 location. Do you think it would be smart to grab an extra set of the PIO for the future. I know from other posts on your opinion that these are military grade and built to last a very long time... but with how fast audio parts seem to go up over the years I did think to inquire. Thanks for your time.
    Roy Mottram
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    Post by Roy Mottram Thu Apr 20, 2023 2:52 pm

    to 45 . . .
    the Mundorf silver/gold/oil caps are around $100 each and are FANTASTIC capacitors, I'd say way above the K40 PIOs, but the K40 PIOs do compare favorably with some other caps in the $20-30 range.
    I've been meaning to write an article on capacitors and post it on my web site but haven't gotten around to it, but here's a copy of some info I sent someone the other day contemplating what caps to use
    in one of my $2000 preamps . . . . K40s are generally very hard to find anymore as they were sourced from Russia, and can't be shipped to USA anymore,
    as well as so popular they were probably getting low on inventory of them anyway. Prices below are for commonly used 0.22uF values. PP is polypropylene, best for most capacitor types.

    the Mundorf EVO are aluminum/PP/oil (about $20 each) and the Mundorf Supreme are silver/PP/oil (about $75 each).
    Another option is AudioCap Theta, which is PP and tin foil, a mid-range option for about $30 each.

    For $3000 speaker pairs, I'd go with the AudioCap Theta, for $5000 speaker pairs, I'd go with the Miflex KPAL (about $30 each)
    for $8000 speaker pairs, I'd go with the Mundorf Supreme, and for $10K+ speakers pairs, the Miflex KPCU-3 (about $30 each)
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    Post by New2Tubez Thu Apr 20, 2023 6:44 pm

    Bob Latino
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    Post by Bob Latino Thu Apr 20, 2023 8:06 pm

    New2Tubez wrote:FWIW, the Miflex KPAL are on closeout at $12 and change each. I hope they'll fit some day:

    https://www.soniccraft.com/product_info.php/miflex-kpal-0022uf-600vdc-aluminum-foil-polypaper-in-oil-p-5267?osCsid=cdsk9p6d7pn89gq2n73bllkpa7

    That cap is a .022 uF at the link that you provided .. What you need is a .22 uF cap to use as coupling caps on the VTA driver board. A .022 is too small and, if used, would hinder the low frequency output of the amp.

    Bob

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    Post by New2Tubez Thu Apr 20, 2023 10:05 pm

    Thanks for catching this Bob. I just emailed to see if I can cancel the order. The next sound will be me kicking myself. :[

    ***Thanks again Bob
         I was able to stop the order in time. Apologies to any of you whom I may have misguided.


    Last edited by New2Tubez on Thu Apr 20, 2023 11:31 pm; edited 1 time in total (Reason for editing : update)
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    Post by vtshopdog Sat Apr 22, 2023 6:47 pm

    I went down the coupling cap rabbit hole for my M125's about 18 months ago and got some excellent suggestions on this thread:
    https://dynacotubeaudio.forumotion.com/t4721-coupling-cap-substitutions

    Ended up using RelCap AudioCap RT series and am happy with the results.
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    Post by WLT Mon Apr 24, 2023 12:02 pm

    I really enjoy my RelCap AudioCap RT in my MK IIIs. Will not be changing them any time soon. Good to see Vtshopdog agrees with my thoughts on them. I am restoring a pair of MK IVs for a friend of mine. Using the Russian K42Y-2 caps for those. I think he will like them and costs are very reasonable.
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    Post by pedrocols Fri Aug 11, 2023 12:48 am

    Here is a pic of Miflex caps on my amps so you can have an idea how big they are.
    Capacitor and sound quality 05F8AAEFC7BB42A08CB1FBD3C1A561C6

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