Fizz Cap

psychodave

Well-known member
Just curious if anyone can hear the difference between close values? For example, can you hear the difference between 47pf and 68pf? I've been tinkering around with values in my Jet City Jose mod, I went with 47pf at first, but was tinkering around with different values. I doubled my original value and went with 100pf. I could clearly hear the amp change. I tried a 68pf cap afterwards, but in the time it takes to swap, I cant be certain I hear the difference between 47 and 68. :LOL: :LOL:
 
I can hear the difference between 47pF and 100pF. If you want to be certain it's not just a mind trick, either build or buy a decade box. Just alligator clip it in and turn the switch while you play. Weber sells one with small pF silver micas. Or build your own.

https://www.tedweber.com/csub-smc

It's a lot easier and faster and you can be more certain when tuning an amp if you use a decade box/switch for the exact reason you said. In the time it takes to swap a part out, you lose your frame of reference. But with a decade box or pot, you can change values instantly as you play and go back and forth to your heart's content. I do this for pretty much every part of the amp. Slope resistor, plate loads, dull caps, cathodes, etc.
 
47p to 68p with the same brand, and capacitor composition, I don't hear much difference. However 47p to 100p yes.

Another thing to note, different capacitor brands, and or composition sound different here. CDE silver mica's sounds different than the cheap no-name silver mica. Also the cheap 1kv ceramics, sounds different compared to those fancy 6kv epoxy dipped ceramic jobs. I actually like the cheap 1kv ceramics the best here.
 
I use the same silver mica caps. I like the idea of a decade box. I might build one and load it with a few different values. I’m thinking it’s splitting hairs...but it’s still interesting to try it and learn for myself.
 
CrazyNutz":2smjp6xl said:
47p to 68p with the same brand, and capacitor composition, I don't hear much difference. However 47p to 100p yes.

Another thing to note, different capacitor brands, and or composition sound different here. CDE silver mica's sounds different than the cheap no-name silver mica. Also the cheap 1kv ceramics, sounds different compared to those fancy 6kv epoxy dipped ceramic jobs. I actually like the cheap 1kv ceramics the best here.

It's hard to get an idea for what parts people talk about because there are like 500 different manufacturer/model/dielectric type of caps whether we're talking silver mica or ceramic disk. So when you say "1kv ceramic" you could be talking about any number of specific parts. Without a manufacturer part number it's kinda vague lol

Can you hear a difference between different dielectric type of class 2 ceramic disks of the same brand? Like 1kv Y7P vs 1 kv X5F
 
FourT6and2":n97vklx5 said:
CrazyNutz":n97vklx5 said:
47p to 68p with the same brand, and capacitor composition, I don't hear much difference. However 47p to 100p yes.

Another thing to note, different capacitor brands, and or composition sound different here. CDE silver mica's sounds different than the cheap no-name silver mica. Also the cheap 1kv ceramics, sounds different compared to those fancy 6kv epoxy dipped ceramic jobs. I actually like the cheap 1kv ceramics the best here.

It's hard to get an idea for what parts people talk about because there are like 500 different manufacturer/model/dielectric type of caps whether we're talking silver mica or ceramic disk. So when you say "1kv ceramic" you could be talking about any number of specific parts. Without a manufacturer part number it's kinda vague lol

Can you hear a difference between different dielectric type of class 2 ceramic disks of the same brand? Like 1kv Y7P vs 1 kv X5F


For ceramic, I usually get something in the class 2 range
X ,or Y
5, 6, or 7
D, E, F, or, P

As for the sound between the different types, I dunno. That would take a hell of a lot of time.

I've got some multi-layer ceramics that are super tiny for their capacitance, haven't tried them on anything yet.

Everything sounds/feels different. You could have the same cap value, and composition but different manufacture, and they will sound different.
I find this rings especially true on med to high gain stuff. When you get into cleaner territory it's not as apparent.
 
FourT6and2":ynm7pps0 said:
So why Class 2 then?

I suppose Class 1 specs seem like overkill, and class 3 specs seem like crap?

In all reality some of the cheap unmarked ceramics I find are probably class 3 or worse, and sometimes these are the ones that sound the best for a particular spot.
 
My take yes there is a difference, but I do not dwell on it. Andy difference can be compensated by a microturn of the treble of presence control. It's a position that I dont dwell on
 
psychodave":tmq45igv said:
Just curious if anyone can hear the difference between close values? For example, can you hear the difference between 47pf and 68pf? I've been tinkering around with values in my Jet City Jose mod, I went with 47pf at first, but was tinkering around with different values. I doubled my original value and went with 100pf. I could clearly hear the amp change. I tried a 68pf cap afterwards, but in the time it takes to swap, I cant be certain I hear the difference between 47 and 68. :LOL: :LOL:
I don't know the amp you are working with, but I believe I am correct in saying there is a resistance involved with the capacitor, and that is material in determining the corner frequency of the low pass filter, either through a single signal path, or through a phase invertor type cancellation.

So that being said, it depends. You will be able to hear the difference more on some amps and less on others, and also more at high gain. I've put in several fizz caps on my phase invertor tubes just after the plate resistors with very good results, but even though the relatively easy calculation indicated the corner frequency (-3db), I still used my ear in the end to pick a proper cap. I suggest you carefully - (watch our for the high voltage !) clip in several different caps as an auditory and functional test, and see what one works the best in your amp, and at the gain level you generally play. If you play just at the point of distortion mostly, your requirements will be different than someone who uses very high gain levels and wants to trim back the buzz.

Good luck with it !
 
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