Resistor Types

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colossal
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Re: Resistor Types

Post by colossal »

JMPGuitars wrote:
Fri 08/16/19 1:12 pm
You're missing an important detail/part of the argument here. HiFi amps want to be clean and distortion free. Even a guitar amp's clean sound has some level of distortion, if it doesn't, it sounds terrible. If every component used in an amp is designed to reduce distortion, then you're potentially negatively affecting desired tone.
The bulk of what we enjoy as distortion is from the design, not the components. The operating point of the tube determined by the load line creates distortion due to uneven distance between grid lines. The contribution to distortion by the parts is small. The contribution to NOISE can be significant. The sterility argument as a function of parts is flawed. I will bet you, in the most gentlemanly fashion, a six pack of your favorite beer right now that your all metal film build will be just as glorious and warm as an all carbon comp build, and very probably even better because of the low Shot and Johnson noise of a good metal film resistor. Metal films get a bad rap likely because the guy shooting off his mouth on the internet came to the conclusion that all metal films result in cold and lifeless amps, because he used some garbage part with steel leads and not-insignificant inductance as well as other undesirable characteristics. All parts are not created equal nor are the builders using them. As you say, lead dress and transformers make a massive difference in how an amp sounds.
Regarding your MF amp build, the only way to determine that being the best build (for that reason), is to double-blind A/B test the same amp with both MF and other resistors. The difference in all the other components, and your skill level at the time of each build, all come in to play. You know all this though. ;)

This is an old (not-very-scientific) demo I did comparing capacitors: https://www.youtube.com/watch?v=kUDhBnMSuG0

I built all 3 amps at the same time, with all the same components, except for the tone/coupling caps. For that demo to be closer to scientific, I should have used the same amp build, and swapped the caps. I should have also used a prerecorded track on my looper pedal to make sure that the playing and levels were the same for each test. Obviously there are other factors too. But still, there's distinct characteristics that are more likely the caps, than the variance between transformer sets. To me, and most of the comments I received, the polyester caps were preferred. That doesn't mean that PP caps don't also sound great. A couple people did like the OD PP caps, but they were the least popular. Still sounded good, but not the best.
Your study was still very good and I thought perfectly valid. You can split hairs ad infinitum with the setup. Guys will talk you to death about the minutiae. The point is, what difference do you hear, if any? I watched that video as well, long time ago. To my ear, in some amps, with Polypropylene you don't get so much of the midrange smear you do with polyester. But the construction of the capacitor will also make a difference in its performance and sound.

Also, just to pour gasoline on the fire...I hear quite a bit of difference between say a Vishay Dale RN65 (metal film) and other metal films.

There is some internet lore that says a guy goes into a music store and asks to try out a Custom Shop guitar. He plays it and then plays the Not Custom Shop version. He then says to the proprietor, "huh, I don't hear a difference so how come that guitar is so much more than the other one?" The shop keep says, "well, if you don't hear a difference, then there must not be one". :lol:
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Re: Resistor Types

Post by JMPGuitars »

colossal wrote:
Fri 08/16/19 2:13 pm
The bulk of what we enjoy as distortion is from the design, not the components. The operating point of the tube determined by the load line creates distortion due to uneven distance between grid lines. The contribution to distortion by the parts is small.
Agreed, the design is always more important. However, a small contribution can go a long way. ;)

Also, just to pour gasoline on the fire...I hear quite a bit of difference between say a Vishay Dale RN65 (metal film) and other metal films.
I'll buy into your hype. :lol: You think I should build with the RN65 series resistors? My laziness doesn't allow me to compare MF vs. MF, only MF vs. CF.

Thanks,
Josh
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Re: Resistor Types

Post by colossal »

JMPGuitars wrote:
Fri 08/16/19 2:49 pm
colossal wrote:
Fri 08/16/19 2:13 pm
Also, just to pour gasoline on the fire...I hear quite a bit of difference between say a Vishay Dale RN65 (metal film) and other metal films.
I'll buy into your hype. :lol: You think I should build with the RN65 series resistors? My laziness doesn't allow me to compare MF vs. MF, only MF vs. CF.

Thanks,
Josh
No hype! Just a statement. I don't even use RN65s and I'm not suggesting you do either, for good or bad. I'm just stating in some work I was doing, I could discern the difference between an RN65 and others. They all had a characteristic. I think it's utterly ridiculous to state unequivocally that one part is better than another. It all depends on the application. For performance such as voltage handling, or slew rate, or ESR, then yeah, there are definite differences even within the same class of part, and some are certainly better than others. But a dull sounding carbon film of a certain manufacture might be the right part to take the edge off a clipping stage, for instance. I think it's like cooking: you follow the recipe to master it, then you take liberties when you understand what each part does.
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Re: Resistor Types

Post by crgfrench »

My personal belief is that the distortion people like in guitar amps is the intrinsic distortion from the tube(s) clipping. All that other stuff is silliness IMHO.
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Re: Resistor Types

Post by Daviedawg »

That is a big can you have just opened and the worms can be vicious.

Harmonics enter the audio equation as well as distortion, clipping and noise. But I am not going there so early on a Saturday morning. Or ever.

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Re: Resistor Types

Post by JMPGuitars »

crgfrench wrote:
Fri 08/16/19 9:39 pm
My personal belief is that the distortion people like in guitar amps is the intrinsic distortion from the tube(s) clipping. All that other stuff is silliness IMHO.
Even if worrying about resistor and cap types is silly (and I won't continue farther into that right now), the tubes are only 1/3 of the amp's distortion (and that's excluding circuit components). You're forgetting about the OT and speaker distortion. And then you can get into another discussion on preamp vs power amp distortion. In a different thread. ;)
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Re: Resistor Types

Post by crgfrench »

JMPGuitars wrote:
Wed 08/14/19 7:11 am
...GVF is the worst thing to happen to rock and roll in at least 20 years. Their sound is TERRIBLE. If GVF played one of my amps, I'd be embarrassed. In case I'm being too vague here, I can't stand them.
Uh oh, now Marshall is promoting the worst thing...
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Re: Resistor Types

Post by JMPGuitars »

As a company, I'm no fan of Marshall at all. Having terrible musical taste doesn't surprise me.
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Re: Resistor Types

Post by crgfrench »

I feel like I need to check out Demob Happy and You Me At Six, never heard of them before...
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