How to improve tube amplifier tone by changing one part

Tube or solid-state, this section goes to eleven!
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FiveseveN
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Post by FiveseveN »

Since "some people" can't be arsed to download a fucking archive, I'll just leave these here. If you want the uncompressed and/or uncut samples you know where to find them.
cap-001.mp3
(3.91 MiB) Downloaded 11 times
cap-002.mp3
(3.91 MiB) Downloaded 12 times
cap-003.mp3
(3.91 MiB) Downloaded 11 times
cap-004.mp3
(3.91 MiB) Downloaded 10 times
cap-005.mp3
(3.91 MiB) Downloaded 11 times
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Post by andy-h-h »

soulsonic wrote:
11 May 2020, 23:28
I just listened to the video. I could hear differences between the different caps, though they were subtle. The first Vishay cap was the least good to my ears. I'll see about downloading the reaper files, because I'm always curious.
I have found on many occasions, that simply replacing this first coupling capacitor has a HUGE impact on the perceived tone of the amplifier -clearer defined high end response and warmer rounded midrange tone. In some cases I have noticed an almost natural reverb and increased sustain of plucked notes by simply changing this ONE capacitor.

Keep in mind the comments we are judging this against. It's a pretty bold statement to make, hence the flame trail.
That's not a blind test, so it's going to be prone to unintentional or subconscious bias to some extent - you'll never even know that you are doing it...

- you knew what you were listening to
- the results were not verified after repeated testing (this involves mixing up the order they are presented)

Unless the results stick out like the proverbial dogs balls (which is kind of the claim by the way), it's best to test assumptions. According to Bajaman the results are HUGE, so it should stick out like dogs balls. I'm an old sound guy, and I could not tell you the amount of times that someone asked me to change something in the monitors, only to say "yeah that's it, that's better now" before I even touched the desk. They heard what they wanted to hear. So this is in part why I'm sceptical without proof. I don't really feel like pulling my amp apart to try it, and even if I did, would the results be unbiased?

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Post by phatt »

andy-h-h wrote:
12 May 2020, 08:04
soulsonic wrote:
11 May 2020, 23:28
I just listened to the video. I could hear differences between the different caps, though they were subtle. The first Vishay cap was the least good to my ears. I'll see about downloading the reaper files, because I'm always curious.
I have found on many occasions, that simply replacing this first coupling capacitor has a HUGE impact on the perceived tone of the amplifier -clearer defined high end response and warmer rounded midrange tone. In some cases I have noticed an almost natural reverb and increased sustain of plucked notes by simply changing this ONE capacitor.

Keep in mind the comments we are judging this against. It's a pretty bold statement to make, hence the flame trail.
That's not a blind test, so it's going to be prone to unintentional or subconscious bias to some extent - you'll never even know that you are doing it...

- you knew what you were listening to
- the results were not verified after repeated testing (this involves mixing up the order they are presented)

Unless the results stick out like the proverbial dogs balls (which is kind of the claim by the way), it's best to test assumptions. According to Bajaman the results are HUGE, so it should stick out like dogs balls. I'm an old sound guy, and I could not tell you the amount of times that someone asked me to change something in the monitors, only to say "yeah that's it, that's better now" before I even touched the desk. They heard what they wanted to hear. So this is in part why I'm sceptical without proof. I don't really feel like pulling my amp apart to try it, and even if I did, would the results be unbiased?
Great comments, well said. :thumbsup

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Post by FiveseveN »

andy-h-h wrote:
12 May 2020, 08:04
I could not tell you the amount of times that someone asked me to change something in the monitors, only to say "yeah that's it, that's better now" before I even touched the desk.
Hehe, live mixing was my day job before The Plague and I've also had this happen countless times. There's also a running joke in the industry about dealing with (usually drunk) patrons who insist on giving advice while you're working: just fiddle with an unassigned knob/muted channel until they inevitably become satisfied.
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

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Post by Optical »

Also, if you can hear it, then you can definitely measure it. So swapping caps and doing some frequency spectrum analysis should clearly show up differences.

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Post by bajaman »

Also, if you can hear it, then you can definitely measure it. So swapping caps and doing some frequency spectrum analysis should clearly show up differences.
Please feel free to do so with the suggested 22n TAD mustard capacitor versus a generic reddish brown chinese 22n 630v polyfilm capacitor with a clean tone - I await the results eagerly :wink:
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Post by bmxguitarsbmx »

Frequency response analysis uses an averaging process. So, if the capacitors are effecting the transient response, then that will be integrated in as only a small percentage of the entire samples that are averaged. As an example, the transient may last0.5ms (Maybe less than a full cycle of wave before it stabilizes) and you may be averaging for 500ms or even a second to generate the response. Transient energy gets buried! Do frequency response graphs show the difference between new strings and old? Some people claim new strings sound different (Cork sniffers). Plus, Your Audio interface has several stages of integration (Coupling caps) and. likely a High pass filter and probably some "NO_DENORMALS" code, so your transient energy will look quite different than it would look on a DC coupled scope (The waveform gets wrapped around zero so that resolution can be split equally between + and - numbers).

For a different example: I have a API preamp that measures flat past 22kHz, but it has phase shift starting at 12kHz. How? I see no Allpass filter. As it turns out, frequency response is actually dropping as harmonics are being are being added. So, it is actually distortion that makes my Spectrum look flat. My Focusrite is equally flat but, for some reason I like to plug into the API (Like a dirty cork sniffer!) In that case, my ears were telling me something was there and the equipment was saying there wasn't. Bias is a real thing, of course. Approaching everything as a skeptic is a good example of a common bias we can all succumb to.

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Post by gght »

FiveseveN wrote:
12 May 2020, 07:01
Since "some people" can't be arsed to download a fucking archive, I'll just leave these here. If you want the uncompressed and/or uncut samples you know where to find them.

cap-001.mp3
cap-002.mp3
cap-003.mp3
cap-004.mp3
cap-005.mp3

Most would be listening on laptop or phone speakers. I doubt that’s a fair assessment.

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Post by andy-h-h »

gght wrote:
13 May 2020, 01:33
FiveseveN wrote:
12 May 2020, 07:01
Since "some people" can't be arsed to download a fucking archive, I'll just leave these here. If you want the uncompressed and/or uncut samples you know where to find them.

cap-001.mp3
cap-002.mp3
cap-003.mp3
cap-004.mp3
cap-005.mp3

Most would be listening on laptop or phone speakers. I doubt that’s a fair assessment.

No, that would not be fair. I'm sure people here are smart enough to use decent headphones or monitors :wink:

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Post by FiveseveN »

bmxguitarsbmx wrote:
13 May 2020, 00:43
As it turns out, frequency response is actually dropping as harmonics are being are being added.
How did you determine this? Was it by properly employing the analytical tools afforded by current technology? Frequency response analysis can't show 'the whole picture', you're right, but it's not the only tool available to us.
Do frequency response graphs show the difference between new strings and old?
Do you have a method for consistently plucking strings, so we may have a chance to determine that? Or are you relying on human muscles controlled by human brains? You might also want to remember that
1. We have a clear theoretical framework about why older strings sound different (grime has mass)
2. There is a unanimous consensus that older strings sound different.
Approaching everything as a skeptic is a good example of a common bias we can all succumb to.
That makes no sense: how can one be biased against being biased? Or is this some straw man skeptic you're describing, akin to the Straw Vulcan?
bajaman wrote:
12 May 2020, 23:27
I await the results eagerly :wink:
I'm sure everyone's at the edge of their seat waiting for someone else to do the work for you.
In the meantime, what we have is one person's opinion versus some evidence, flawed as it admittedly is.
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

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Post by rockola »

bmxguitarsbmx wrote:
13 May 2020, 00:43
Approaching everything as a skeptic is a good example of a common bias we can all succumb to.
Nothing to do with bias. Lack of bias is not a bias, just as atheism is not a religion. Approaching everything as a skeptic, as you put it, is what science is at its very heart. If a physical phenomenon can't be measured, nor identified with confidence in a blind test, it does not exist. To claim otherwise is to open the door for all the spoon bending psychics of the world.

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Post by deltafred »

I listened on Beyerdynamic DT990 headphones and didn't hear any difference.

Disclaimer - after 50+ years of gigging in noisy ass rock bands I'm surprised I can still hear at all!
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Post by bmxguitarsbmx »

rockola wrote:
13 May 2020, 07:54
bmxguitarsbmx wrote:
13 May 2020, 00:43
Approaching everything as a skeptic is a good example of a common bias we can all succumb to.
Nothing to do with bias. Lack of bias is not a bias, just as atheism is not a religion. Approaching everything as a skeptic, as you put it, is what science is at its very heart. If a physical phenomenon can't be measured, nor identified with confidence in a blind test, it does not exist. To claim otherwise is to open the door for all the spoon bending psychics of the world.
Atheism is religion. Atheists are bought into a set of ideas and they use those ideas to self-righteously judge the world around them- all while ironically accusing religious people of being self righteous and judgemental.

But to the point: Acting "scientifically" and being a "Skeptic" are two different things. I will clarify that I am not talking about Double blind testing. I'm talking about trusting your ears and keeping an open mind to other possibilities. That is why I told that story about the preamp. In the beginning, my ears were telling me one thing and the measurement equipment was telling me I was wrong. There is a possibility that there is another explanation. All I am saying. I am not at all saying this is not worth experimenting with, essentially that is why we are all here. If it was easier to do double blind tests, I would do more. Double blind tests might be the slow road to discovery however. So, again, MAYBE you can trust your ears. If you don't want to, I won't force you too.

My apologies to FiveSeven. I made a mess of my quoting up of my reply to you.

I thought you might find the observation about Spectrum analysis averaging the transient energy into the entire sample to be more interesting. It is just an example of the limitation of that one particular measurement. Other measurements will have their own unique limitations. I don't know, we may have to use our creativity to understand some of the less obvious limitations.

As far as the "being a skeptic is a bias in itself": Let's say that a scientist has done a serious of tests to determine if various things are true or not and the end result is everything that has been tested is false. Now the scientist might become a little bit skeptical of things that are supposedly true. The scientist is becoming biased/skeptical. The bias that I identify in a skeptic is "That everything is bullshit". Hey! Maybe it is! Maybe there is more to it. If I can only make one point, it would be that you skeptics come in hot with your "Myth buster" stamps. There might be other explanations. It's like you are way too eager to get all the parameters of the experiment so you can quickly post up some evidence to prove it is BS. Sorry man, seems like you are biased.

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Post by andy-h-h »

I think there's some confusion as to what the word sceptical actually means. It's not short hand for being argumentative about everything. Being sceptical about certain claims just mains that you are awaiting proof. i.e. I'm not sure about this (based on past experience perhaps), let's see the proof. It doesn't mean one is sceptical about everything.

skeptical (about/of something) having doubts that a claim or statement is true or that something will happen
- I am skeptical about his chances of winning.
- The public remain skeptical of these claims.
- She looked highly skeptical.

PS Atheism is not religion, although I agree some act the way you described.

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Post by FiveseveN »

bmxguitarsbmx wrote:
13 May 2020, 22:15
Atheism is religion.
Aaaand you've disqualified yourself from grown-up discussion. So I was right, the issue was you're just fighting a straw man, born from an incorrect definition/vision of skepticism.
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

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Post by okgb »

I don't mind a little mojo voodoo, as long as I'm not getting ripped off for it, but where there is money/value there will be judgment
Is this worth it ? is it 20.00 better ? am I smarter than the average guy [ my mom said I was special ]
and there is always the "Emperor's new clothes " factor where everyone wants to be thought of as smart & able but afraid to admit being wrong or unable to hear it.

nothing wrong with questioning things or considering , Do I hear anything different ? cultivating your listening skills can only help you.
On the video they seemed to get a little brighter and or louder as they went on, to me, It's helpful to be able to drop in the middle of them and mix up the order to shake up any perceived differences. when I did that with the clean examples posted here, nothing jumped out as sounding much different

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Post by plush »

okgb wrote:
14 May 2020, 17:02
I don't mind a little mojo voodoo, as long as I'm not getting ripped off for it, but where there is money/value there will be judgment
Is this worth it ?
This whole thing makes no sense provided every mojo voodoo being a rip-off a priori. :D

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Post by okgb »

Right , if it's free, it's for me ! as in I'm not going out of my way to over pay for expensive caps and my opinion [ perceptions ] is the only thing it costs me
so if it makes one feel better because it looks more orange let em have their place & peace it's not hurting you.
and some things are reasonably priced, carbon vs metal film resisters ? to each their own! Is this the gear page ?

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Post by soulsonic »

When my photo students would ask me which camera to buy - Nikon, Canon, Sony, etc... - I decided the best thing to tell them was just go with whichever one has the features you need and makes you feel good. And since nearly all of them have almost same features, at least in regards to what was required for the course, it pretty much just came down to whichever one makes you feel the best.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran

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Post by Manfred »

A friend of mine and I talked a long time ago about the cause of the differences some people heard about after replacing the capacitor types.
We could not investigate the differences further because my friend died too early and unexpectedly, that was very sad.
He was a graduate engineer for high frequency technology by profession.

The influence of the capacitance by DC voltage (bias DC voltage) on the capacitor is well known in HF technology, because the change of capacitance caused by this can cause problems.

Another cause can be the non-linear characteristic of the capacitance as a function of the applied DC voltage.
This non-linearity depends on the material of the dielectric and varies from non-existent to very strong.

This means that the non-linear characteristic generates harmonics which make the sound spectrum either more pleasant or less pleasant.

The closer the DC bias voltage is to the maximum permissible DC voltage of the capacitor, the stronger the effect of the capacitance change. The capacitance change would then have to be caused by the AC signal voltage added to the bias DC voltage, and the filter characteristic frequency would change with the signal amplitude and signal frequency, for example.

But this is only a brief attempt of a physical explanation and a speculation which has to be checked by measurements.

Here is another article with explanations, measurements and field reports about the topic capacitor types in audio technology.
The language can be chosen on this page:
https://www.gitarrenelektronik.de/facha ... ?showall=1
The author Mr. Lemme, graduate physicist, is known for his contributions in Music Electronics over decades.

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