# Amp Cap Shootout - Generic Poly vs Mallory vs SoZo



## jbealsmusic (Feb 12, 2014)

Robbie ordered a custom amp from Calvin (McCormick Analog). It's a champ-like amp with an added boost section and custom tone control. When it was completed, Calvin was kind enough to drop by and swap the signal caps a few times so we could do a demo/shootout between a few different cap types (Generic Poly, Mallory 150, and SoZo). The caps were selected and measured, ensuring their capacitance matched to eliminate variation due to manufacturing tolerances. The settings and mic placement were identical each time (we had stoppers to get the amp back in the same spot every time).






I am super skeptical of this kind of stuff, so I expected minimal difference. Robbie, also skeptical, but more open minded than me was open to the possibility of a difference. Calvin knew there would be a difference, but wasn't expecting it to be quite as obvious as it was. In the end, we were all a little surprised that the results were as audible as they were. Though, still pretty minute in the grand scheme of things.

To put an arbitrary number on it, let's say 99% of the tone is the circuit design, that last 1% is in the specific component selection.

Thought it was a cool experiment that some might enjoy, so I figured I'd share it here. Looking forward to doing more!


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## greco (Jul 15, 2007)

Cool thread! Thanks to everyone for going to all of the work to put it together.

Personally, I preferred #1 (SOZO)

@jbealsmusic I suspect the poll will prove to be very interesting!


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## jbealsmusic (Feb 12, 2014)

greco said:


> Cool thread! Thanks to everyone for going to all of the work to put it together.
> 
> Personally, I preferred #1 (SOZO)
> 
> @jbealsmusic Would you consider adding a poll to this thread?


We all preferred #1 on first impression after the blind test, so you're not alone there!

Poll added.


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## DavidP (Mar 7, 2006)

Question: So each of these sets were tested 'fresh' immediately after installing??? 
FWIW, in my experience, caps need some 'burn-in' time to settle in and really show what they're like.


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## jbealsmusic (Feb 12, 2014)

DavidP said:


> Question: So each of these sets were tested 'fresh' immediately after installing???


Sort of? We actually went through the entire process twice because of a technical error, so they weren't totally fresh. The caps he originally had in were the generic ones, so they probably had 30-60min of play time prior to this test. The others had maybe a couple of minutes each before the final test that you hear in the video.


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## jb welder (Sep 14, 2010)

The tubes are ageing, the wall voltage may be fluctuating... 
Just kidding. I didn't really find the difference all that drastic (compared to a speaker swap, for example).

I thought it was nicely done. Was concerned about the signal source so very pleased to see the looper in use.
If I can nitpick about one technicality, I'd rather them be referred to by material they are made of, rather than brand. (as far as the Sozo and the 150's, I believe they are different material, not sure about #3)

As far as making conclusions, that can be tricky. In this particular application, it seemed the #2 was judged to be more harsh. The assumption then becomes that they add harshness. But what if they are the truly transparent, and the amp is harsh? Then the #1 are actually colouring the sound and taking away an inherent characteristic.
Maybe in a pristine clean setting, the #1 would actually dull some 'sparkle'? Lots of different scenarios to consider.

I will say that I am somewhat dissappointed in the marketing angle of the Sozo's. Similar to the groove tube and mercury mag. type stuff that leans heavily toward imparting 'sound' qualities that are pretty judgemental and not very science based. But this is the whole boutique thing I guess.

Dying to see the part 2 shootout with the Sozo 'yellow' vs 'blue'.


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## Paul Running (Apr 12, 2020)

jb welder said:


> As far as making conclusions, that can be tricky. In this particular application, it seemed the #2 was judged to be more harsh. The assumption then becomes that they add harshness. But what if they are the truly transparent, and the amp is harsh? Then the #1 are actually colouring the sound and taking away an inherent characteristic.
> Maybe in a pristine clean setting, the #1 would actually dull some 'sparkle'? Lots of different scenarios to consider.


I agree with this statement, there are variables here that should be eliminated. You may wish to test the capacitor by itself, including the critical parameters that are key to the tone...mix some science in with the art. A capacitor can be shown as an equivalent cct.; each of the components that represent the cap could be tested and then related to sonic quality.









* Equivalent cct. of a cap.*


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## jbealsmusic (Feb 12, 2014)

Paul Running said:


> I agree with this statement, there are variables here that should be eliminated. You may wish to test the capacitor by itself, including the critical parameters that are key to the tone...mix some science in with the art. A capacitor can be shown as an equivalent cct.; each of the components that represent the cap could be tested and then related to sonic quality.
> 
> View attachment 349394
> 
> * Equivalent cct. of a cap.*


We didn't want to get too deep because we wanted this to be accessible to everyone. But indeed. It shouldn't be forgotten that ESR and numerous other factors can vary in the manufacturing process, not just the capacitance.

Probably the only impression that can be drawn here is that there can be a difference in sound, even if the capacitance matches. Some combination of the other factors may impact the tone.

So the question becomes, would we get similar results with numerous versions of the same type/brand of cap with matching capacitance, possibly because of the variability of those other factors?


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## jbealsmusic (Feb 12, 2014)

jb welder said:


> The tubes are ageing, the wall voltage may be fluctuating...
> Just kidding. I didn't really find the difference all that drastic (compared to a speaker swap, for example).


Agreed. The difference is minimal, but it is there. Which is what was surprising to me.



> If I can nitpick about one technicality, I'd rather them be referred to by material they are made of, rather than brand. (as far as the Sozo and the 150's, I believe they are different material, not sure about #3)


As far as I recall, all 3 are polyester film.



> As far as making conclusions, that can be tricky. In this particular application, it seemed the #2 was judged to be more harsh. The assumption then becomes that they add harshness.


This is where language fails me. I was merely observing that one was perceptibly brighter than the others when the amp was breaking up. Whether that's because it is adding brightness or the other caps take it away wasn't really my point. Like my comment in the video, I'm not sure how to word it better, but I wasn't assuming either way. Just trying to put my observation into words.



> But what if they are the truly transparent, and the amp is harsh? Then the #1 are actually colouring the sound and taking away an inherent characteristic.
> Maybe in a pristine clean setting, the #1 would actually dull some 'sparkle'? Lots of different scenarios to consider.


Agreed!



> I will say that I am somewhat dissappointed in the marketing angle of the Sozo's. Similar to the groove tube and mercury mag. type stuff that leans heavily toward imparting 'sound' qualities that are pretty judgemental and not very science based. But this is the whole boutique thing I guess.


Couldn't agree more. I absolutely hate marketing speak with a furiously passionate anger that will likely eventually lead to my downfall. It's incredibly difficult to market music products without it, and it is a source of much frustration for me.



> Dying to see the part 2 shootout with the Sozo 'yellow' vs 'blue'.


Oh yeah. I forgot they had blue ones. Are they actually different, or do they just put a blue jacket on them? Kind of like another company marketing vintage bumblebee caps.


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