Microphonic 6PS caps

[CoffeeTones]

Hello, I have about 10 of each common value, 600V, 6PS caps from .0012 to .22uF. These were bought from AES. I was locating the outer foil on each cap through an amp and test box. I notice that some are microphonic way more than the others, in the same values. Some have a thud with pinging / ringing sound and some just have a thud sound, when tapped between two fingers. Some barely make any noise, just a light bump sound.

They have all tested okay in capacitance and DC leakage at 350VDC. I tested some other, various brand caps and none had the ping / ringing noise many of the 6PS had.

Is there an explanation for the noise they make, so I can feel comfortable building an entire amp with them? I'd like some opinions and facts on this if possible, please.

Thanks

[JazzGuitarGimp]

I have no facts to espouse. Opinions, I've got.... My thinking is, a guitar is a hostile environment in terms of vibration, and this is especially true for combo amps. Any component that is microphonic, and is exposed to vibration, is going to add some sound of its own to the signal path. I would avoid the microphonic ones at all costs.

[bluesfendermanblues]

......
Is there an explanation for the noise they make, so I can feel comfortable building an entire amp with them? I'd like some opinions and facts on this if possible, please.

Thanks

I don't have an explanation either, but it must stem from tiny movements in internal parts. I use them (6PS/600) in three Dumble clones and even though I
notice the same sound artifacts, when "Chopstick'en" the amps on the bench, I was never bothered when playing the amp ...might even be beneficial in providing the 'special sound'.

The cure/usual procedure for prohibiting movement is 'fixing' them to the board with a little silicone.

[Stevem]

This is why in a combo amp I land every cap that has signal running thru it down with silicone sealer!

On some big pancake type Ciramic caps you can talk right into them like a Mic!

[TUBEDUDE]

The ringing indicates internal movement, even with elephant snot holding the cap to the board, there might still be oscillation of the internal foil bundle. if it persists, call it a feature. Specially selected caps that are chosen to create ambience and air.

[CoffeeTones]

The amp is a Dumble ODS type.

I think I may use the quietest 6PS caps out of the bunch, however that eliminates 90% of the 6PS caps I bought. I certainly do not want to fight parasitics, and microphonics in the circuit. I really see no way to avoid problems with the way these caps are behaving.

Maybe the stock of 6PS caps is breaking down. Which would be some good suggestions for alternatives to 6PS throughout the amp?

Caps I have....

1. Mallory 150, white and yellow caps which I never care for.(white ones seem sterile, buzzy and light on bass freq)
2. Sozo yellows - good all around but maybe not for an ODS
3. Mojo brand, which are close to Sozo to me
4. Xicon MPP - great in Blackface Fender, strong bass
5. 716P - never tried these throughout any amp
6. A mix of new and old 225p - These seem okay in Fender Brownface amps.

[CoffeeTones]

......
Is there an explanation for the noise they make, so I can feel comfortable building an entire amp with them? I'd like some opinions and facts on this if possible, please.

Thanks

I don't have an explanation either, but it must stem from tiny movements in internal parts. I use them (6PS/600) in three Dumble clones and even though I
notice the same sound artifacts, when "Chopstick'en" the amps on the bench, I was never bothered when playing the amp ...might even be beneficial in providing the 'special sound'.

The cure/usual procedure for prohibiting movement is 'fixing' them to the board with a little silicone.

Not delving too far into myths, but do you recon that this is the reason Dumble gooped his amps rather than the usual belief that he was concealing the circuit?

[norburybrook]

......
Is there an explanation for the noise they make, so I can feel comfortable building an entire amp with them? I'd like some opinions and facts on this if possible, please.

Thanks

I don't have an explanation either, but it must stem from tiny movements in internal parts. I use them (6PS/600) in three Dumble clones and even though I
notice the same sound artifacts, when "Chopstick'en" the amps on the bench, I was never bothered when playing the amp ...might even be beneficial in providing the 'special sound'.

The cure/usual procedure for prohibiting movement is 'fixing' them to the board with a little silicone.

Not delving too far into myths, but do you recon that this is the reason Dumble gooped his amps rather than the usual belief that he was concealing the circuit?

I'd had that thought as well before now.

marcus

[ToneMerc]

Not delving too far into myths, but do you recon that this is the reason Dumble gooped his amps rather than the usual belief that he was concealing the circuit?

No, my third and final conversation with HAD which was decades ago and must have been one of his special days, he was adamant about hiding his circuitry. I wish I could have recorded that 9 minute phone call, it would be a YouTube classic!

TM

[ToneMerc]

Hello, I have about 10 of each common value, 600V, 6PS caps from .0012 to .22uF. These were bought from AES. I was locating the outer foil on each cap through an amp and test box. I notice that some are microphonic way more than the others, in the same values. Some have a thud with pinging / ringing sound and some just have a thud sound, when tapped between two fingers. Some barely make any noise, just a light bump sound.

They have all tested okay in capacitance and DC leakage at 350VDC. I tested some other, various brand caps and none had the ping / ringing noise many of the 6PS had.

Is there an explanation for the noise they make, so I can feel comfortable building an entire amp with them? I'd like some opinions and facts on this if possible, please.

Thanks

I have run across a few that were, in fact IIRC I mentioned it here in one of my early builds that I replaced one because I felt causing an issue I could hear.

TM

[bluesfendermanblues]

......
Is there an explanation for the noise they make, so I can feel comfortable building an entire amp with them? I'd like some opinions and facts on this if possible, please.

Thanks

I don't have an explanation either, but it must stem from tiny movements in internal parts. I use them (6PS/600) in three Dumble clones and even though I
notice the same sound artifacts, when "Chopstick'en" the amps on the bench, I was never bothered when playing the amp ...might even be beneficial in providing the 'special sound'.

The cure/usual procedure for prohibiting movement is 'fixing' them to the board with a little silicone.

Not delving too far into myths, but do you recon that this is the reason Dumble gooped his amps rather than the usual belief that he was concealing the circuit?

No I believe he wanted to protect his designs.

Myth or not - having build dumble clones for 8 years and reading the post at the dumble forum more than once, I've arrived at the conclusion the dumble amps are the result of a man who can listen to a top and actually build an amp around that particular players technique and style using a combination of tech skills and golden ears.

So with dumble there's no simple answers. The man has golden ears and the ability to tweak on and on until he reaches perfection - like with Robbins amp.

[CoffeeTones]

Not delving too far into myths, but do you recon that this is the reason Dumble gooped his amps rather than the usual belief that he was concealing the circuit?

No, my third and final conversation with HAD which was decades ago and must have been one of his special days, he was adamant about hiding his circuitry. I wish I could have recorded that 9 minute phone call, it would be a YouTube classic!

TM

May be the reason DF is so patient when I ask him questions, even though sometimes he avoids me!

Which caps do you think would deliver the goods in an ODS, closest to the 6PS?

[CoffeeTones]

No I believe he wanted to protect his designs.

Myth or not - having build dumble clones for 8 years and reading the post at the dumble forum more than once, I've arrived at the conclusion the dumble amps are the result of a man who can listen to a top and actually build an amp around that particular players technique and style using a combination of tech skills and golden ears.

So with dumble there's no simple answers. The man has golden ears and the ability to tweak on and on until he reaches perfection - like with Robbins amp.

I'm very confident he and Ken Fisher discovered some things about lead dress. Believe it or not, you CAN drastically change the tone and personality of any amp with lead dress. They can be made thin and lifeless as well as thick, juicy and blooming, just by lead dress. I can do it and it is repeatable, on the fly.

[dorrisant]

I'm very confident he and Ken Fisher discovered some things about lead dress. Believe it or not, you CAN drastically change the tone and personality of any amp with lead dress. They can be made thin and lifeless as well as thick, juicy and blooming, just by lead dress. I can do it and it is repeatable, on the fly.

I have done this with an Express and others in the past... Higher gain circuits tend to do this the most. I remember reading someone's post here and thinking that I had to see how much it could change... very big improvement.

[ToneMerc]

No I believe he wanted to protect his designs.

Myth or not - having build dumble clones for 8 years and reading the post at the dumble forum more than once, I've arrived at the conclusion the dumble amps are the result of a man who can listen to a top and actually build an amp around that particular players technique and style using a combination of tech skills and golden ears.

So with dumble there's no simple answers. The man has golden ears and the ability to tweak on and on until he reaches perfection - like with Robbins amp.

I'm very confident he and Ken Fisher discovered some things about lead dress. Believe it or not, you CAN drastically change the tone and personality of any amp with lead dress. They can be made thin and lifeless as well as thick, juicy and blooming, just by lead dress. I can do it and it is repeatable, on the fly.

I said many times before that IHMO I think ODS amp are the sum of several small things, not necessarily one key ingredient. When you work those several small things, the magic happens, these small things are things that one might otherwise overlook. More than once I have had an ah ha moment and realized that despite HAD's quirks and flaws, he is really a genius.

TM