heres an odd one

[Tage]

So would it simply be a better idea to use film caps for bypass? I use them almost exclusively, nice small low voltage ones, most with very low esr, and way tighter tolerances than most electrolytics.

[exclamationmark]

I'd say it was probably the tolerances that were affecting things. 20% is a lot - but the difference can still be bigger in extreme cases! If one capacitor was -20% out of spec and the other was 20% over spec, you have a 40% difference in value! If you have a capacitance meter (most multimeters nowadays have this built in), you could try and measure them and see if there are any differences. Of course being electrolytic capacitors, they're not exactly the 'ideal' capacitor. I generally use film capacitors for anything under 4.7u - they're quite easy to get a hold of in <63v ranges.

[Steve Conner]

That's why you need a very large and expensive meter that goes: "boing"

Timeless words of wisdom

I'd just like to point out that an 0.68uF electrolytic probably has lousy ESR compared to a 22uF electrolytic, let alone an 0.68uF film cap. Also, when a 0.68uF is used as a cathode bypass cap, there'll be lots of signal voltage across it, and electrolytics are known to generate distortion under these conditions.

So yeah, there is more to it than "0.68uF". Hopefully you just got some bad ones with extremely high ESR, and replacing them with 0.68uF film caps would give the same good tone.

[pdf64]

I don't know about more recent Marshalls, but JMPs used monster big mustards for the 0.68uF cathode bypass.
Pete

[daz]

Timeless words of wisdom

I'd just like to point out that an 0.68uF electrolytic probably has lousy ESR compared to a 22uF electrolytic, let alone an 0.68uF film cap. Also, when a 0.68uF is used as a cathode bypass cap, there'll be lots of signal voltage across it, and electrolytics are known to generate distortion under these conditions.

So yeah, there is more to it than "0.68uF". Hopefully you just got some bad ones with extremely high ESR, and replacing them with 0.68uF film caps would give the same good tone.

I do have some .68 film caps, but i have used them in the past and not noticed any difference. Maybe they just aren't that different from the original electros i have, tho it seems weird the 2 electros sound much different than the films vs the original electros. I suppose it could be at the time i used the films the amp wasn't as sensitive to cathode caps. I HAVE notice with some circuit configurations the cathode components seem to make a lot more difference than others. But i will try those films again now and see how it sounds.

[soundguruman]

I do have some .68 film caps, but i have used them in the past and not noticed any difference. Maybe they just aren't that different from the original electros i have, tho it seems weird the 2 electros sound much different than the films vs the original electros. I suppose it could be at the time i used the films the amp wasn't as sensitive to cathode caps. I HAVE notice with some circuit configurations the cathode components seem to make a lot more difference than others. But i will try those films again now and see how it sounds.

Unfortunately, there are many perimeters of sound quality, that we have no method of measuring.
There is no meter, that equals the quality of the human ear.
We have many speakers and amplifiers, that are highly regarded as sounding "the best."
YET we have no real conclusive measurement that explains "WHY" we think it sounds the best.

You can measure all day long, with your large and expensive meter, that goes: "boing."
But none of your meters equals the quality of the human ear.
And for those tone-deaf, non musical techs who can't hear the differences, you are utterly clueless that the REST of us CAN hear a difference.
Can I tune a piano by ear? Yes
Can YOU tune a piano by ear? No, of course not, because you can't hear the differences between one note and the next!

So stop your pummeling, of those who can hear the difference. I can see that you are tone deaf. But that does not grant you the license.

[wyatt]

Unfortunately, there are many perimeters of sound quality, that we have no method of measuring.
There is no meter, that equals the quality of the human ear.
We have many speakers and amplifiers, that are highly regarded as sounding "the best."
YET we have no real conclusive measurement that explains "WHY" we think it sounds the best.

You can measure all day long, with your large and expensive meter, that goes: "boing."
But none of your meters equals the quality of the human ear.
And for those tone-deaf, non musical techs who can't hear the differences, you are utterly clueless that the REST of us CAN hear a difference.
Can I tune a piano by ear? Yes
Can YOU tune a piano by ear? No, of course not, because you can't hear the differences between one note and the next!

So stop your pummeling, of those who can hear the difference. I can see that you are tone deaf. But that does not grant you the license.

Stop.

You are being rude, a bit arrogant, and making assumptions about others you can't prove and it's not the way people should behave.

Tuning pianos is about pitch, not tone. Even those with perfect pitch ... or those with autism ... or even those with sound-color synesthesia ... are subject to the limits of perception that R.G referred to earlier in the thread when to comes to tone. Hearing tone and seeing color are not absolutes, that's why there are industry-established neutral references that all sound and film professional rely on.

Yes, best is subjective. And that means I can't rely on your ears, or R.G.'s ears, or Daz's ears or the ears of anyone else to tell me what I find best. That is the root of the phrase "in matters of taste, there can be no argument." It means arguing over subjective taste is moot, everyone likes what they like, there is no better or worse.

The basic rule of thumb is, if you are the only one in the room who can notices a difference...chances are the difference is only in your head.

As for the OP, Daz, you can't just look at the caps, the tolerances of all the components on both turret-boards can mean a difference in sound between the amps. But if you feel something is working, pull it out, measure it, measure a replacement and install it and check out the final effect.

[nickb]

You can measure all day long, with your large and expensive meter, that goes: "boing."

Arrgh - you just had to make me get out my $5000 meter! Would you believe it? It doesn't even go boing! But, it does give me this:


The two green lines show the change in frequency response using a +/-20% tolerance capacitor.
The two blue lines (yes, there are two) show a perfect 0.68uf and a 0.68uF cap with a really bad ESR of 15 ohms.
I think this demonstrates that the differences are
(1) Easily measured
(2) Primarily due to tolerance
(3) Not due to ESR

Edit: BTW, I measured the ESR of a 1uf in my parts bin as 2.9 ohms

[soundguruman]

Stop.

You are being rude, a bit arrogant, and making assumptions about others you can't prove and it's not the way people should behave.

Tuning pianos is about pitch, not tone. Even those with perfect pitch ... or those with autism ... or even those with sound-color synesthesia ... are subject to the limits of perception that R.G referred to earlier in the thread when to comes to tone. Hearing tone and seeing color are not absolutes, that's why there are industry-established neutral references that all sound and film professional rely on.

Yes, best is subjective. And that means I can't rely on your ears, or R.G.'s ears, or Daz's ears or the ears of anyone else to tell me what I find best. That is the root of the phrase "in matters of taste, there can be no argument." It means arguing over subjective taste is moot, everyone likes what they like, there is no better or worse.

The basic rule of thumb is, if you are the only one in the room who can notices a difference...chances are the difference is only in your head.

We merge music with electronics.
The tone deaf might understand the "electronics" part...
but the other 50% of the problem---knowing if the sound is right or not?
That's where you fail, so miserably. You don't know the difference, because you can't hear the difference.
And you try to compensate for your lack of understanding, by attacking those who CAN hear the difference.

Do certain capacitors, tubes, components sound better?
Of course they do. But only to those who are not tone-deaf.
That leaves about 50% of you "techs" out of the equation...

[Jazz P Bass]

Sounds like 'Voodoo' to me!

[wyatt]

We merge music with electronics.
The tone deaf might understand the "electronics" part...
but the other 50% of the problem---knowing if the sound is right or not?
That's where you fail, so miserably. You don't know the difference, because you can't hear the difference.
And you try to compensate for your lack of understanding, by attacking those who CAN hear the difference.

Do certain capacitors, tubes, components sound better?
Of course they do. But only to those who are not tone-deaf.
That leaves about 50% of you "techs" out of the equation...

Horse-pocky.

You don't know me at all, the best you can offer is a straw man in my place. I know better than to follow you down into the muck. I have more than a dozen textbooks on mental perception within 10 feet of me, backed by roughly 30 doctorates, I think the others get a general feel from your objectivity and expertise at this point, they can believe what they want to.

[Steve Conner]

I believe that for every audible difference between two sounds, there is a measurable difference. If you recorded the two sounds using our present-day audio technology, the waveforms would be different in a way that some sort of mathematical analysis could uncover.

In many cases, the difference isn't obvious using our usual test instruments (oscilloscope and spectrum analyser) and it's simply not worth the time to figure out an analysis that would uncover it. Nevertheless I believe that it is there.

I then turn this argument backwards: If some proposed change to a circuit wouldn't change the electrical characteristics of it, then it must make no difference to the electrical output, and therefore it can't make an audible difference to the sound of an audio circuit.

It follows that if one .68uF capacitor sounds different to another, there must be an electrical difference between them. Most likely one of them was not .68uF.

It also follows that some "audible differences" don't exist at all and are best explained by pure imagination.

This applies on every level, so for instance some feature of the design of an output transformer or tube could not affect the sound unless it also affected the electrical performance. Do paper bobbins sound different to plastic ones? Yes, if they have different thicknesses and geometries that force different winding patterns, which they do.

[pdf64]

'The tone deaf might understand the "electronics" part...
but the other 50% of the problem---knowing if the sound is right or not?'
My understanding is that someone who's tone deaf would be able to appreciate and distinguish timbre, eg I recall reading that Leo Fender was tone deaf.
Pete

[Steve Conner]

Don't know about that, but we do know Leo didn't play guitar, which explains why all his amps sounded so bad.

[R.G.]

That's where you fail, so miserably. You don't know the difference, because you can't hear the difference. And you try to compensate for your lack of understanding, by attacking those who CAN hear the difference.

Do certain capacitors, tubes, components sound better?
Of course they do. But only to those who are not tone-deaf.
That leaves about 50% of you "techs" out of the equation...

Wow. That post says more about the poster than the target.

@SGM: I suggest you look up "DARVO". I've had an unwanted introduction to these terms in my extended family, but they explain a lot. DARVO is an acronym for Deny, Attack, and then Reverse Victim and Offender. It's a great way to move a discussion from any technical content into a discussion of personalities and personal abilities.

I translate that post as "I'm right. If you disagree with me, YOU'RE wrong; moreover, your wrongness leads you to attack your betters, and your wrongness is a kind that cannot be helped, because it comes from an innate lack of ability in you."

The hifi tweako school of audio criticism has long held that micro-differences in sound quality exist that can only be heard by special individuals with superhuman abilities of hearing discrimination. Even more, that if instruments can't find a difference heard by these special "Golden Ears", then it follows that the *instruments* are wrong.

That explanation has a lot of snob appeal. I'd suggest re-reading "The Emperor's New Clothes", but you've doubtless already thought of that, right?

The problem with the hifi tweako Golden Ears manifesto is that it fails simple testing where a Golden Ear is pitted against itself by double blind testing of whether a Golden Ear can reliably pick out whether there is a better, worse, or no difference in repeated samples of audio. Golden Ears usually wind up doing worse than random chance in such tests. Golden Ears got so burned in things like this that they refuse to take the test for a variety of reasons that sound suspiciously like rationalization.

Can you hear what you're saying? Probably not. The personality quirk that uses DARVO is marked by an inability to see what they are doing objectively, no matter what, or how it's pointed out to them. The ultimate problem with this world view is that it is self reinforcing and eventually diverges from the real, objective external world. The tragedy is that when this happens, the internal inability to see it leaves the person unable to correct back to the real world.

I suppose another way of saying this is that just like "tone deafness", there is a real disorder that we might call "selective real world deafness", an inability to perceive facts that don't line up with a person's internal ideas. It's as real a personal lack as any tone deafness.

IMHO, 'guru' is a title that properly should be bestowed by others, not self-adopted.