Now for some bright/treble cap snakeoil trials

[pjd3]

Hey there,

OK, I allow myself one or two "snake-oil" components in my builds just because I can. This time it is $11.00 Sozo caps and some polystyrene caps from JustRadios.

When I built this stereo amp I put all Vishay MKT1813 polyester films into the Bright and the Treble positions just for the fudge of it, start there, move into the micas or others later up the road. I do find that to get the EQ balance I go for, the presence and treble knobs are much higher up than my other amp of the same preamp type (plexi) but, I realize there can be a myrid of other factors driving that. Now that I have a decent ideal with the basic sound of this amp is over a handful of gigs, I'm ready to do some experimenting. (I will become the "snake oil King" of capacitors).

So, lets have some fun. If you were going to try a Sozo 1000v 500pF cap and a 630V polystyrene (styrex I guess it somethings called,), What positions would you be inclined to land them on given the bright cap and the Treble cap? Would you put the mica in the bright or the treble? They polystyrene in the bright or treble?

Of course I will try both over time but my first inclination was to put the Sozo in the treble position, and the polystyrene in the bright cap position. I figured let the polystyrene pass the highs through with out much bias, and then let the "forward" presentation of the mica do its thing in the treble position. AI however was all for the other way around and gave quite an explicit description as to why its preference would be superior. Of course, I dont know if AI has golden ears but, I take it with a grain of salt even though I respect its diligence.

I realize that this post is going to be for either great snake-oilists or for those who have done diligent A/B testing but, it would be really fun and interesting to hear your projection on what you might expect sonically, if you expect anything at all.

All snake oil type bullshit is welcome. Let me have it!
Thanks,
Phil D

[Colossal]

I'm not trying to be dissmissive here, but find what works for you. These threads seem to stir up controversy and division where there is none. Some people can hear a difference in the change in sound a certain capacitor/dielectric makes, some can't. It's not snake oil, just a capacitor. The audible effect depends greatly on the amp topology, guitar and pickups, speakers, even how much cable you have out front and its capacitance...and of course if you have the bandwidth to even hear it.

The fun is trying different parts and dialing in your amp and sound. There was a gentleman here that posted that he hands-down preferred polystyrene throughout the amp, not just bright and treble cap positions, and that the difference was very obvious and very much for the better. I voice an amp to get as much apparent depth out of the sound (think 3D shimmer and clarity without sounding flat and right at the surface of the speaker, if that makes any sense).

[pjd3]

I should have left a disclaimer,

I'm not looking to be fixed, or proselytized, or even educated.

The post is simply asking, "what would you do"? I'll find what I find. Its just interesting to hear from others. When I say "snake oil", its just a play on the words that insinuate some kind of "special component" which we know is just BS but, hey, it might be apparent to some folks.

As a matter of fact, I do have plans for a stereo amp that uses all polystyrenes and polypropylenes and ultra-linear output transformers, just because I want to hear how that sounds with one- or two-amp modeling pedals I have. I figure the worst that can happen is I spend money and time on something I don't like! If so, I'll just go grab a pizza or something.

Thanks,
PHil D.

[martin manning]

Just do it. You may struggle to hear a difference, but those are two likely spots, particularly the treble. You might want to change only the treble cap and listen to both dielectrics there. Record the present circuit for a baseline before changing anything. Not too long, but get a few chords and some single notes over a range of frequencies. Keep it short to avoid ear fatigue. Swap to another type, play, listen, and record that. Change to the other dielectric in and repeat. This is much less effort than changing all the caps, so very manageable. Play the recordings back to back to see if your live impression is confirmed.

[jbrrrrr]

I would recommend recording your trials, keeping as much consistent between takes as you can besides the caps: guitar, pickup selector, tone and volume knobs, amp setting, position of pick from bridge and where the stroke happens in relation to the pickups, etc. The mind is a curious thing and will absolutely "lie" to you when you try to retroactively assess subjective things like which capacitor had a more pleasing response. Even if it's not to get anyone else to agree with you, I personally wouldn't find much value in doing a test like that without at least some objective standard to examine it against.

Maybe take a baseline recording at least with the current caps, and then for how you assess new caps against it, record a successive take with the new cap(s), and compare the recordings. Get granular and look at an FFT plot too if you feel like really trying to understand what your ear finds pleasing - it might surprise you by being contrary to what you think it is, and would give you some useful information on caps as well as your particular preferences, which would help inform what choices to make later when faced with looking at a frequency plot and having to make a call on that alone.

[pjd3]

Thanks jbrrrr,

I trust my own perceptions with what I will find. I was more curious what others have done and what their perceptions were of what they did and found.

I might not hear anything no matter what I do, or, get hyper focused and hear things that aren't even there. And either of those is OK I guess.

Thanks,
Best,
Phil D.

[nuke]

The "taste test" threads sometimes get boisterous.

I'm not a believer in magical parts. I do use some of the boutique things, when someone specifically asks for them, like a restoration of a vintage amp. Sometimes it preserves the value when originals are simply not going to work or be available.

But I am a believer in picking the right part for the job, and choosing the dielectric and construction method and the vendor's quality reputation is part of that. Different dielectric materials have different properties. Most audio work is really not all that demanding. But it is good to know some choices may not be suitable, such as some ceramics introduce microphonics (or they "sing" in things like switch mode power supplies).

When I buy caps to stock, I'll generally pick polypropylene radials and axials in common values, because as coupling caps go, they'll work about as well as a capacitor can possibly work. I'll also keep some mylar caps on hand, because sometimes I need the smaller size.

In small value (pf) usually I wind up with silver mica since they're readily available in high voltages and relatively small, and the name brand ones are generally reliable and stable. Polystyrene has the best dielectric properties, but they're not as readily available and are a bit delicate for soldering. Ceramic NP0 and C0G capacitors are generally fine in audio stages, where some of the other dielectrics exhibit undesirable microphonics.

Taste test away, it is really a matter of personal opinion. I'd add in there's some value in including cost, package type, availability as well as subjective opinions of audio. If you have a suitable LCR meter, a detailed set of measurements such as ESR, inductance, dielectric absorption, theta and so on are really helpful to the discussion.

[flemingmras]

I'm not trying to be dissmissive here, but find what works for you. These threads seem to stir up controversy and division where there is none. Some people can hear a difference in the change in sound a certain capacitor/dielectric makes, some can't. It's not snake oil, just a capacitor. The audible effect depends greatly on the amp topology, guitar and pickups, speakers, even how much cable you have out front and its capacitance...and of course if you have the bandwidth to even hear it.

The fun is trying different parts and dialing in your amp and sound. There was a gentleman here that posted that he hands-down preferred polystyrene throughout the amp, not just bright and treble cap positions, and that the difference was very obvious and very much for the better. I voice an amp to get as much apparent depth out of the sound (think 3D shimmer and clarity without sounding flat and right at the surface of the speaker, if that makes any sense).

Yes but in this thread, the OP presents it as snake-oil and not "empirical proven gospel because my favorite "amp guru" wrote an article about it" unlike some of the know-it-alls around here.

[Fischerman]

I'll fully admit that the only reason I put foo foo parts in an amp build is because I'm only building it once. It's a hobby.

[pjd3]

Haaaa, I have a very, very embarrassing admission to make here - but I deserve whatever heckling I get, (because I know that none of you "ever" did anything like this.

So started my stereo amp build with the full intention of going against the grain and use regular old MKT1813 polyesters for both the bright cap and the treble cap. The worst that could happen is I didn't like the treble end of things as much as all my other builds, and I would gradually move the bright and treble caps back towards the usual types, silver mica, and maybe do one of those with my favorite "snake oil" (theres that freegan word, again), the Sozo 11 dollar super/mega mica cap that "eliminates out of band resonances" and keeps your highs all nice n stuff.

So tonight I bench my chassis and get ready to do the deed - (Sozo super duper cap in bright pos, and a parallel of a CDE mica with a polystyrene to equal the 470pF for the treble cap. 10 minutes had gone by, and I still couldn't find the "original bright cap" that of course is hiding in there somewhere. After dismissing my self as blind and/or crazy I came to the realization that I forgot to install the damn bright cap. When this amp was completed, biased up and getting the initial woodshedding, I was struck at how thick and darker these amps were compared my last build which was the same circuit but with tube rectifier. At gigs I was very surprised how much further I had to turn up the treble and the presence to reach my desired top end of things. This stereo amp was simple two diode rectification so, I simply blamed the "relative darkness" or lack of treble on the polyester brt/trb caps and maybe some difference in the power node applications to the rest of the amp. So, that's alright and all but, I was really curious to hear what a poly bright cap sounded like and if or how much difference there would be to a Siver mica cap in the bright position.

I'm just really surprised I did that, left out a bright cap. I really haven't ever left a component out like that before, being the worry warting over vigilant belligerent ruminator that my wife tells me I am.

OK, so, can't wait to hear this thing now. I have no idea what to expect but thats OK. I'm going to definitely learn something here.

Thanks for hanging with me on this.
Best,
Phil D - I'll report back on the findings on the next trial which will likely be tomorrow night after work.

[pjd3]

I hear ya fisherman,

If I was Leo Fender I'm certain we wouldn't be seeing any $11.00 caps in any position.

Of course, his amps all look more professional than mine. But we still have time!

Best,
Phil D.

[Roe]

There were some earlier posts here about these sozo caps, suggesting they sounded relatively dark.

Anyway, plexis did not use silver micas.

[pjd3]

My last build was a single channel 20 watt plexi that did have silver mica in both the bright and treble positions.

It was bright alright but nothing a little Presence and Treble controls couldn't reign in.

Now, lets see what the new caps do for the tone in this stereo 20 watt plexi.

While its on the bench, I'll do a good Preamp tube plate voltage check to make sure we are in a good place. I believe I did that during the finishing of the amp but, cant remember. This one is a SS rectified amp so, I would naturally expect the preamp tubes to be seeing 15-20 higher voltages. That could be a good thing since this amp is a pedal platform and not something I would ever be purposely overdriving. I have the right kind of tubes in V2 to handle "heater-to-cathode" breakdown voltage differential.

Best,
Phil D.

[nuke]

By the mid 60's, the "black face panel" era, the Fender amps were designed and built generally as commercial audio equipment. Those blue Ajax caps were pretty standard for commercial/industrial electronics at the time, and generally a step above most consumer equipment. That's why even 60 years later, they're still working. As things progressed through the end of the silver panel era, they changed suppliers, but mostly stuck with commercial grade components. Not extravagant, just decent parts common in the industry.

There really wasn't any cork-sniffing going on, they tuned things up to please the buyers and build sturdy equipment that would hold up on the road.

In the pF range, you'll see a variety of caps, ceramics and so on, just depends on the supply chain at the build time. But you'll see appropriate choices, just not exotic choices.

All of these elemental circuit components are measurable. Put them on a suitable analyzer that measures their parameters in depth and you'll find there are differences, even between polyester and polypropylene or mica vs. styrene vs. ceramic. You can model those in circuits to determine what, if any, deltas they create in the circuit performance.

[pjd3]

Hey nuke.

I've never had a doubt about caps having varying characteristics. The place I work designs and manufacturers lifesaving equipment that is chock full of all kinds of electrical systems, and the engineers are very aware of the electrical characteristics of the various cap types and where in the circuits they should go or not go to perform in a certain manner.

And although I haven't experienced firsthand what different caps will sound like in various positions of a guitar tube amp, I have no reason to doubt that there are people who hear differences, some a little difference some a lot. So, I thought this thread would be an opportunity to hear from others what "they" had experienced with this. I think that got terribly lost in translation somewhere and pretty much everyone tried to "straighten me out" or "enlighten me" and thats OK, there is sure alot of room in me for education and enlightenment. But since I am making this my first opportunity to finally A/B some differences myself, I thought I'd hear out others experience with this, particularly, the bright and treble positions with the cap types I mentioned, because that's what I had.

Tomorrow I'll get the chassis back in the cabinet and hear what these caps with do compare to what was in there. You can probably tell, I am very curious to see if I hear differences and what they are.

Thanks nuke,
Best,
Phil D.