Are carbon films worth the trouble?

[FUCHSAUDIO]

I just serviced a Carr with a noise complaint. They recommended changing some resistors to metal film, from the carbon film they shipped it with. the funniest part is they sent the customer an actual Fender Deluxe reverb schematic, and said "your amp is very similar to this one" and marked up the schematic with a highlighter to show suggested resistors to change...I found that hilarious....

Anyway: The reverb mix stage was particularly problematic and yes, metal films cleared up the issue to the tune of a few db. Honestly, the noise wasn't what I considered "substantial", but the dude is a jazz player and plays at near acoustic volumes with an upright bass player, and the hiss bugged them both.

[WhopperPlate]

I think of it all this way : if I could build an amplifier and make it sound exactly the way I want utilizing nothing but the most reliable bulletproof and industry approved components I would without batting an eye .

If that was solid state footprint amp I would be in heaven . Before I built my own amps I tried everything I could to avoid tube amplifiers . I wanted reliability and consistency, something I could not get with the tube amps that I had available. Tone was the trade off .

you can try to do one nice experiment...cheap.. build your favorite preamp (JCM800? ) and send the output after master volume to the 100W CLASS D output power module,
you can find them cheaply from ebay (LJM LJM)
You will be surprised about the tone, which is between Valve and Solid state (has warmth + light compression+dynamic from the valves, and speaker control from the solid state!) also there is no ugly clipping like solid state amp!

I have tried all sorts of line out preamp out slave arrangements , but I will admit I have never attempted ti build my own standalone preamp to utilize with solid state , let alone the newest equipment available .

The class D stuff is definitely getting better. Listen to those live clips of Eric Gayles and Joe bonamassa dueling guitars and you can hear that the Eric’s raw dawg class D amp is competing nicely with the dumble …tube pre solid state back end …but you can definitely hear the difference in character.

That being said, solid state sounds and feels very very quick . Too quick ime. Focused like a laser . I can hear where it ends and begins .

[WhopperPlate]

Anyway: The reverb mix stage was particularly problematic and yes, metal films cleared up the issue to the tune of a few db. Honestly, the noise wasn't what I considered "substantial", but the dude is a jazz player and plays at near acoustic volumes with an upright bass player, and the hiss bugged them both.

One man’s negligible is another man’s substantial .

[Reeltarded]

Class D works great. I am running whole amps into it, but it works even best as far as amplifying program. It should be fast. I don't want 5% slew rate after the fact. If you buy Class D, over do it by >10x. If you want 100w stereo you need 2000w-4000w rating. That will keep you thermally far in bounds and it will find structural issues in most any venue. It's fairly clinical. WYHIWYG

[Reeltarded]

and said "your amp is very similar to this one" and marked up the schematic with a highlighter to show suggested resistors to change...I found that hilarious....

Second easiest modern amp I ever worked on and I should otherwise keep my opinion to myself!

[R.G.]

Setting up a non-biased test of whether a component matters is a demanding process. Remember - it's first and foremost a test of the person's ability to sense a difference. Only after verifying that the person can hear a difference can you begin testing components. In testing the person, you're in essence calibrating a test instrument - that being the person themselves. After all, if hearing a difference in components is as easy as some people claim, this should be very easy. Right?

People are extremely resourceful at sensing things, and especially at using every possible clue to sense whether (for instance) there is a tiger making that branch move or if it was a bird or the wind. We automatically and unconsciously combine all the factoids we can sense and then our minds make up a supposed picture of what's happening. We are completely unaware of all the things that go into a first impression/picture/memory. Our brains also edit and change memories in real time, changing the initial impression-memory to fit what the mind finds out seconds or day later plus any pre-existing memories or biases.
Designing a test of human perception is notoriously difficult. A great deal of effort is needed to keep the person from getting any external information about the test. The Clever Hans thing is one example. The owner had to be not visible to Hans to get a fair test of just Hans, not Hans plus the owner. Humans are much, much more capable at putting together subtle clues than Hans.

Appropriate test design is two stages. First, test the humans. Humans are known to vary widely in their auditory discrimination abilities; otherwise, everyone would be a Golden Ear, right? It is impolite and incorrect these days to say that someone is better than someone else in any way, but that is the result of lots of psychoacoustic experiementation. The somewhat predictable result of any test showing that anyone can detect (in this case...) subtle differences in the sound of components will be met with outrage and denial. Everyone can hear as well as everyone else ... maybe.

[bepone]

My friend , who is deaf like a doorpost , but when he was tweaking his amp and changed MF dale to cheap MOX 2W in cathode on PP amp 18W with EF86 on V1, all happy, reported a change, that "upgrade" was definitely better (for him ).
So we are not speaking about 0.00001% change , i can say maybe... 5%?

[WhopperPlate]

Setting up a non-biased test of whether a component matters is a demanding process. Remember - it's first and foremost a test of the person's ability to sense a difference. Only after verifying that the person can hear a difference can you begin testing components. In testing the person, you're in essence calibrating a test instrument - that being the person themselves. After all, if hearing a difference in components is as easy as some people claim, this should be very easy. Right?

People are extremely resourceful at sensing things, and especially at using every possible clue to sense whether (for instance) there is a tiger making that branch move or if it was a bird or the wind. We automatically and unconsciously combine all the factoids we can sense and then our minds make up a supposed picture of what's happening. We are completely unaware of all the things that go into a first impression/picture/memory. Our brains also edit and change memories in real time, changing the initial impression-memory to fit what the mind finds out seconds or day later plus any pre-existing memories or biases.
Designing a test of human perception is notoriously difficult. A great deal of effort is needed to keep the person from getting any external information about the test. The Clever Hans thing is one example. The owner had to be not visible to Hans to get a fair test of just Hans, not Hans plus the owner. Humans are much, much more capable at putting together subtle clues than Hans.

Appropriate test design is two stages. First, test the humans. Humans are known to vary widely in their auditory discrimination abilities; otherwise, everyone would be a Golden Ear, right? It is impolite and incorrect these days to say that someone is better than someone else in any way, but that is the result of lots of psychoacoustic experiementation. The somewhat predictable result of any test showing that anyone can detect (in this case...) subtle differences in the sound of components will be met with outrage and denial. Everyone can hear as well as everyone else ... maybe.

This is not nearly as insurmountable of an obstacle as the long winded essay of low expectations would suggest…

Let’s pretend that’s not the issue…now go

[WhopperPlate]

My friend , who is deaf like a doorpost , but when he was tweaking his amp and changed MF dale to cheap MOX 2W in cathode on PP amp 18W with EF86 on V1, all happy, reported a change, that "upgrade" was definitely better (for him ).
So we are not speaking about 0.00001% change , i can say maybe... 5%?

I regularly interview people who don’t even care about guitar , namely my wife and her friends, non musician friends , and plenty of musicians . You know what they all have ? Very strong opinions about the differences they hear between A and B . The more times I test them the more they notice and then easily determine a choice. It’s crazy how many random golden ears I have amongst my friends and associates …

[WhopperPlate]

Class D works great. I am running whole amps into it, but it works even best as far as amplifying program. It should be fast. I don't want 5% slew rate after the fact. If you buy Class D, over do it by >10x. If you want 100w stereo you need 2000w-4000w rating. That will keep you thermally far in bounds and it will find structural issues in most any venue. It's fairly clinical. WYHIWYG

If you are slaving whole amps that’s one thing , fast can be ideal , and I would be curious to hear class D in that application . I personally always felt slaving was just a bit too distant between me and the speaker . The less I have between that and myself the better, hence my proclivity toward amps with old school amps with only a few gain stages .

I hear ya on power , more headroom the better essentially with slaving in general

[Guy77]

My friend , who is deaf like a doorpost , but when he was tweaking his amp and changed MF dale to cheap MOX 2W in cathode on PP amp 18W with EF86 on V1, all happy, reported a change, that "upgrade" was definitely better (for him ).
So we are not speaking about 0.00001% change , i can say maybe... 5%?

Hi I was curious which cathode position was this in the amp.

Thanks
G.

[R.G.]

My friend , who is deaf like a doorpost , but when he was tweaking his amp and changed MF dale to cheap MOX 2W in cathode on PP amp 18W with EF86 on V1, all happy, reported a change, that "upgrade" was definitely better (for him ).
So we are not speaking about 0.00001% change , i can say maybe... 5%?

Great! I'm glad he was happy with his work.
Unfortunately for the question at hand, his attestation that it was a great improvement is what's called "anecdotal evidence". An anecdote is of substantially no value in proving that something is or is not. This is because people can see and hear things that they just make up inside their heads, and hear them different ways.
This is not to say that he does not hear it as better. He almost certainly does. But does that mean everyone would think it was great? Almost certainly no. So one anecdote is worth about zero at proving things like this. Actually, a thousand anecdotes are worth the same as one anecdote.

Did he make any other changes in his amp while "improving" it?

There is a human bias to think our own work is amazingly good. It's subtle, and all we can do is be aware that we think anything we do while "improving" something is a step in the right direction. And if we believe our bias, it is completely true - inside our own head, but not necessarily outside in the real world.

[Reeltarded]

Another example of the more simple circuits likely being most revealing. The 86 is strong.. the tubes in that amp are all very strong and reveal their sonic nature (I would say) a bit more obviously than other common types . Anything other components do would be most obvious in this sort of situation.

There is this thing that goes unnamed that is evident in mic amp comparisons. Some Neves almost build a virtual space. It's weird and other-worldly. Just patching the device makes even the line noise dimensional. Some are transformerless signal paths.

Reality is complicated!

[R.G.]

This is not nearly as insurmountable of an obstacle as the long winded essay of low expectations would suggest…

That would be really great!

I'm always eager to learn. Sketch out for me in some detail how it's not nearly as insurmountable.

Let’s pretend that’s not the issue…now go

We can do that - pretend that's not the issue. How does that give us an honest, fair and impartial test?

[bepone]

Hi I was curious which cathode position was this in the amp.

hi it was on first V1 valve close to input jack, EF86, cathode resistor 2k7,