Ceramic Cap Discussion from Jazz Mode Video Demo With Stratocaster and 102

[norburybrook]

this one Martin

The ones that have the most impact are Clean tone stack then HRM.. then master vol (if you have one) and bright cap.. then V1B 220k bypass last. is what I hear.

BTW. Yes SM caps can make an amp sound sterile/anemic/strident/HiFi/to bright/harsh and at it's worse ice pick, are generally the cork-sniffer terms used to describe them.

Tony


@Tony , I don't use pedals and have been running wet/Dry for a while so the main amp is always just gtr/cable/ amp-FX are on a separate amp and spealer. Regarding the NOS dales,no you didn't miss anything. I shall start a new thread.


M

[Charlie Wilson]

If I made add, another not so great spot for mica is OD snubbers.
CW

[talbany]

I'm trying to understand why the type of cap used in this location would not matter...

Martin just so we are clear. I didn't say it would "not matter" I said it wouldn't have as much of an impact (difference) as a treble cap in a tone stack with 200+Vdc on it.
Starting a discussion on which type cap used in a bypass spot sounds or if someone can hear a "difference" is IMO a different topic and an argument waiting to break out. So I am not going there too subjective!..My original post to Chris was about the SM in the tone stack.

@Marcus. Lookin forward to your new post on the Dales.

If I made add, another not so great spot for mica is OD snubbers.
CW

@CW. I have not tried them there yet but good to know.THANKS!
Tony

[martin manning]

I'm trying to understand why the type of cap used in this location would not matter...

Martin just so we are clear. I didn't say it would "not matter" I said it wouldn't have as much of an impact (difference) as a treble cap in a tone stack with 200+Vdc on it.

I'm with you... "matters less" would have been better.

I'm concluding that the voltage effects are likely the key here, as mentioned above. According to the curves in the Op-Amp tech paper Erwin posted, if one were to compare different ceramic cap types of the same marked value in the treble cap location, the in-circuit capacitance could differ by as much as -50% due to the applied DC, making the Z5U sound more trebly or thinner. Then, the AC effect would tend to make some dielectrics sound less trebly with the capacitance shift at high volume. It's again basically nothing for NP0, noticeable with X7R, and quite significant for Z5U. This effect could be reduced significantly with high voltage (1kV) caps. The distortion effect (~1% THD for X7R) may be noticeable too, but mostly at lower frequencies, say below 1kHz.

I had not seen any such data before, so thanks again Erwin for posting that!

PS, perhaps this ceramic capacitor discussion could be snipped from Chris' demo thread, and made into a new one with an appropriate title?

[erwin_ve]

I had not seen any such data before, so thanks again Erwin for posting that!

Yes you're welcome. it is always good to know what makes the clock tick.
On a sidenote; a engineers nightmare might be gold for the one who plays it! Remember one of the Dumble stories where Eric Johnson wasnt satified with his sound, Dumble changed parts, EJ was happy, Dumble responded ; he likes cheap parts

[martin manning]

Well-behaved is always easier to deal with, but if there are tonal benefits, the messy characteristics may be worth the trip. That increases the need to understand them, IMO. Otherwise, it’s going to be very difficult to find the sweet spot.

[talbany]

The in-circuit capacitance could differ by as much as -50% due to the applied DC,
Then, the AC effect would tend to make some dielectrics sound less trebly with the capacitance shift at high volume.
The distortion effect (~1% THD for X7R) may be noticeable too, but mostly at lower frequencies, say below 1kHz.

BINGO!

find the sweet spot

Martin IYO?
So out of the 2 classes of ceramic caps (Class 1 and class 2) would best be suited for "electric guitar" and better yet which ceramic type would you then pick given the voltages we normally run. (THD below 1K being a good thing) X7R ??

PS, perhaps this ceramic capacitor discussion could be snipped from Chris' demo thread, and made into a new one with an appropriate title?

Yeah This discussion should be preserved in a separate thread for easy search

Tony

[martin manning]

So out of the 2 classes of ceramic caps (Class 1 and class 2) would best be suited for "electric guitar" and better yet which ceramic type would you then pick given the voltages we normally run. (THD below 1K being a good thing) X7R ??

"Class 2" covers a lot of ground, so let's say we have a choice of X7R or Z5U. Repeating what was said above, a higher voltage rating reduces the capacitance change at a given voltage level, and in any case the fact that the capacitance value will be selected appropriately makes the DC voltage effect a non issue. The AC voltage effect of reducing highs at higher signal levels does seems like it would be in the right direction, but I see poorer temperature stability and drift over time as being clearly undesirable, so X7R wins. I see 1kV X7R's in original D amps (124 photos). As for the distortion effect, IDK if that's a good thing or a bad thing. The paper linked above only gives THD. Aiken says ceramic caps produce "very high odd-order harmonic distortion (the "bad, or harsh-sounding" kind), typically mostly 3rd and 5th and 7th harmonics." It would be interesting to try an NP0/C0G in that location, but its value would need to be adjusted. I think it's safe to say that if HAD didn't like the sound of a ceramic cap in that position, he wouldn't have used it, provided there was some better option available. Notice that in "Mid Boost" he goes to a film cap.

[talbany]

So out of the 2 classes of ceramic caps (Class 1 and class 2) would best be suited for "electric guitar" and better yet which ceramic type would you then pick given the voltages we normally run. (THD below 1K being a good thing) X7R ??

"Class 2" covers a lot of ground, so let's say we have a choice of X7R or Z5U. Repeating what was said above, a higher voltage rating reduces the capacitance change at a given voltage level, and in any case the fact that the capacitance value will be selected appropriately makes the DC voltage effect a non issue. The AC voltage effect of reducing highs at higher signal levels does seems like it would be in the right direction, but I see poorer temperature stability and drift over time as being clearly undesirable, so X7R wins. I see 1kV X7R's in original D amps (124 photos). As for the distortion effect, IDK if that's a good thing or a bad thing. The paper linked above only gives THD. but I see poorer temperature stability and drift over time as being clearly undesirable, so X7R wins.

So given how widely used ceramic caps are in guitar amps (vintage and new) and the rather large role they play in the overall sound of a guitar amp and given the poor stability and inconsistency's they tend to have (based on the specs) that this could be a rather large factor in how the amp performs. We all know how inconsistent guitar amps are. If we find a treble cap that generates the perfect amount of 3rd and 5th harmonics is microphonic just enough to ring at the right frequency's and cuts the right amount of high end when the AC is increased could be the difference in an OK sounding amp or one that sounds/performs spectacularly. Did we just make a breakthrough

The AC voltage effect of reducing highs at higher signal levels does seems like it would be in the right direction

So in the ODS case where you have both clean and overdrive signals working in the amp the cap will actually "reduce highs" when you go to the OD side IMO would definitely be in the right direction. Especially in an HRM

but I see poorer temperature stability and drift over time as being clearly undesirable, so X7R wins.

Or could be you like the sound better after it has drifted?..(I wonder if this could be part of the reason why Dumble gooped that spot to help with stability and microphonics?)

Aiken says ceramic caps produce "very high odd-order harmonic distortion (the "bad, or harsh-sounding" kind), typically mostly 3rd and 5th and 7th harmonics.

This is what we refer to as the hair around the note!.3rd and 5th harmonics are not always a bad thing (especially in an amp with overdrive) IMO it just depends on how dominant they are in relation to the fundamental. This will probably vary wildly cap to cap and is more than likely the reason why most here say you have to roll through several until you find one that has as you say "sweet spot" harmonically.

BTW.Thanks Erwin for posting that PDF!!
Tony

[Charlie Wilson]

The "cheap" ceramics seen in many of the bluesmaster photos are NTE. They aren't actually that cheap(cost wise). They are Y5P and 1000v(for values 270pf and 330pf). I am frankly not as concerned with the first letter of the code as I measure them usually at room temperature and find a 10% change over an increase of 85 degrees (C) acceptable. I am pretty sure my amp doesn't heat up to 185 degrees (F) on the input side at least. Oh yeah, they sound great. Not "hairy" on the top end but actually a bit mellow. Dumble used them because they sound good.
CW

[talbany]

The "cheap" ceramics seen in many of the bluesmaster photos are NTE. They aren't actually that cheap(cost wise).

Nothing from NTE is "cheap" I wonder who makes them? Do you know CW?

Tony

[Charlie Wilson]

Tony, I am pretty sure they are Asian made. I called NTE not too long ago and spoke to someone and the conversation started out OK but soon words like "proprietary" and "weekend electronic hobbyist" started being used. They are in New Jersey, so I let them know what I thought of Bon Jovi and click they hung up. Unfortunately the current production ceramics are being switched over to these blue epoxy covered caps and they don't sound so great. I find that the any of the shinny epoxy ones I have tried including the yellow Panasonics are kind of stiff sounding.
CW

[M Fowler]

I like Bon Jovi or I did when he first arrived on the scene.

Not sure about NTE but every electronic sales shop around the USA had them.

Like you said probably repackaged China electronics.

Mark

[martin manning]

So given how widely used ceramic caps are in guitar amps (vintage and new) and the rather large role they play in the overall sound of a guitar amp and given the poor stability and inconsistency's they tend to have (based on the specs) that this could be a rather large factor in how the amp performs. We all know how inconsistent guitar amps are. If we find a treble cap that generates the perfect amount of 3rd and 5th harmonics is microphonic just enough to ring at the right frequency's and cuts the right amount of high end when the AC is increased could be the difference in an OK sounding amp or one that sounds/performs spectacularly. Did we just make a breakthrough

That’s a lot of speculation beyond the measured data :^) Traditional locations for ceramic caps, from the early Fender era, are bright caps, treble caps, and shunts across the PI anodes. Dumble added plate to cathode shunts on the OD stages. First and foremost I think the type selection was made because of the small values, with mica and ceramic being most common below say 1000pF. Mica was used in very early Fenders, but later they were dropped. That may have been cost driven. I think a lot of understanding has been gained here due to some new data coming to light, so yes a “breakthrough” of sorts.

So in the ODS case where you have both clean and overdrive signals working in the amp the cap will actually "reduce highs" when you go to the OD side IMO would definitely be in the right direction. Especially in an HRM

I’d like to see that hypotheses proved by substituting in NP0/C0G caps.

This is what we refer to as the hair around the note!.3rd and 5th harmonics are not always a bad thing (especially in an amp with overdrive) IMO it just depends on how dominant they are in relation to the fundamental. This will probably vary wildly cap to cap and is more than likely the reason why most here say you have to roll through several until you find one that has as you say "sweet spot" harmonically

This would also need proof, IMO. Is it the cap doing it or the tube in OD mode?

[talbany]

Tony, I am pretty sure they are Asian made. I called NTE not too long ago and spoke to someone and the conversation started out OK but soon words like "proprietary" and "weekend electronic hobbyist" started being used. They are in New Jersey, so I let them know what I thought of Bon Jovi and click they hung up. Unfortunately the current production ceramics are being switched over to these blue epoxy covered caps and they don't sound so great. I find that the any of the shinny epoxy ones I have tried including the yellow Panasonics are kind of stiff sounding.
CW

CW
Figures! When pics of this BM you posted surfaced around 2006/07 I hunted around for this cap. The only way to identify them at the time was the printing on the cap. The only ones I could find with the exact labeling/printing (on e-bay) just said Made in China so I ordered a bag like 100 for 3 bucks from some electronics store named I cant remember. When I got them I tried a few and they were all over the place sound-wise. Maybe had I gone through the bag I would have been able to find some useable ones. I ended up using most as snubbers. I don't know if these were the same ones NTE gets but they looked like them?. In my early tweaking days we went through a ton of different type ceramics (class 1 &2) and remember passing on most of the Panasonic's as they seemed a bit lifeless sounding.This was a while ago. probably worked great in a CD player

BTW.You should have said Springsteen.
Thanks for the info!!

Tony