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need help with upgrading capacitors in a tube amp

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charlies_mpls

Member
Joined 2024
#1
The audio bugs are getting back to me. I want to upgrade the caps in a tube amp: 0.10uF 600V film capacitors.

I did a bit of homework and found this: https://forum.bottlehead.com/index.php?topic=11668.0
quote, "I bought a pair of Audiocap PPT Theta 0.10uF 600V Film/Foil Capacitors for about $15 USD", by Natural Sound. that was a post from 2019.

but when I look it up. it is more than $70 now for a pair on part express. ouch
https://www.parts-express.com/Audio...lVpu8zb7CyDHJJ21JhQv_excdUjrmcT0aAiEPEALw_wcB


any suggestions? any other caps that will work as well as Audiocap?

I found this one: Jantzen Audio 0.10uF 1200V Z-Superior Capacitor.
https://www.parts-express.com/Jantz...ztNmDwHO8qpDNragLEBeapt2Q95TWts8aAvPxEALw_wcB


or this one,
https://www.digikey.com/en/products/detail/nichicon/PHC1604200KN/13662904?utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax Shopping_Product_Zombie SKUs&utm_term=&utm_content=General&utm_id=go_cmp-17815035045_adg-_ad-__dev-c_ext-_prd-13662904_sig-Cj0KCQjwhtWvBhD9ARIsAOP0GojGhwOGG7w3brDbw14rqoqIV5aPXe6X-mP1Sps8MkFSS6YhQgA-xfkaAgTFEALw_wcB&gad_source=1&gclid=Cj0KCQjwhtWvBhD9ARIsAOP0GojGhwOGG7w3brDbw14rqoqIV5aPXe6X-mP1Sps8MkFSS6YhQgA-xfkaAgTFEALw_wcB



mundorf for $15:
https://www.madisoundspeakerstore.c...yZXZwMOTTZ8ODXOf1UC0mdWJKpacBnzoaAiDBEALw_wcB


Thank you in advance. Have a great weekend!
 
#4
charlies_mpls said:
any other caps that will work as well as Audiocap?
Click to expand...
If you look at that other post, some are saying caps make zero appreciable difference. Is _Audio_cap just riding on a myth, compared to the film caps you already have? This film, that film type cap begins to go over the disbelief line for me; sure oil or Al-Els could have a different sonic sig, but film to film, really? Maybe one kind has steel wires, as it was made to start a motor or something...
 
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#14
As long as it’s a film cap you are using you should be good. There are diminishing returns on those high end caps, are $70 cap is not 7x as good as a $7 cap. It might be 2% better, if that much. I use Clarity caps because it walks the line between average and stupid expensive. Don’t go crazy chasing an insignificant improvement, it will never end!
 
#15
dotneck335 said:
Wima MKP4J031004D00KSSD Film Capacitor 630V .10uF 10% 77¢
Click to expand...
When I was a kid, my parents took me to NJ to visit my mother's relatives. We shopped at some very large dept store and I distinctly recall the Grundig radios on display sounding better, somehow, than other sets. FF 20 years later and I picked up some Grundig radio speaker set at a flea market. I had to go into it for some reason and noticed it was full of WIMA caps. An ah-ha moment.

At DEC, they used them in the power supplys they were designing, which I was doing design verification test on. After the design was finished, they'd pitch the stock of those big square red ones at 0.47, 630V into the trash, which I was happy to scrounge. I recall having 2 of those in each of a pair of Dyna MKIIIs I had at the time, before moving out west to work for Intel.

Another 25 years has passed and I'd still recommend them for audio signal coupling. I'm sure there's something "better"...perhaps with less harsh highs someone thought they heard sometime, for 100X.
 
#18
pblix said:
I've seen comparative tests of caps and Wima usually score near the bottom on linearity. Go figure.
Click to expand...
I swapped in what should have been (from specs, the data sheet and from later measuring the impedance curves), an identical Wima 30uf film cap in place of a Solen film "fast cap" as the first cap in a tube rectifier power supply. The Wima cap ruined the bass response in the amp. I was honestly expecting no change or possibly a minor improvement given how hyped Wima caps are. The effect was not subtle at all and installing a Solen cap back into the amp brought back the bass response.

I can honestly say this was not expectation bias, as I said, I wasn't expecting there to be any change and previously held the belief these Wima caps were "top shelf for audio use" devices. What caused this? I have no idea, but I plan to stick with using those solen fast caps in my power supplies.

I get people believe these $0.75 devices are the equal of anything out there, I just wonder if those folks have actually back to back listened to the various caps to come to this conclusion, or if they are just looking at data sheets and specs like I did, thinking there can't be any difference? Again, I was shocked when I powered up this amp and the bass response was gone after this power supply cap change.
 
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