Resistor Types

[crgfrench]

Without AC running through the resistor along with DC, there is no "resistor distortion". The whole idea of resistor distortion adding a second order harmonic requires that the resistor is in the audio signal path. And plate resistors are not in the audio signal path.

[crgfrench]

I just noticed that Danny Russell uses CCs in one spot only: the PI grid leaks. Hmm... Greta Van Fleet plays these.

Alice in Chains plays Meteopoulos, I feel like George isn't slinging "BS hype". He is a professional builder and amp tech. That said, I wouldn't use them in the input section where he indicates.

Who plays Keen's amps? I can't seem to find his builds anywhere.

[Daviedawg]

Gawsh. I missed all this while I was asleep.

A long long time ago I was told by a radio engineer who worked to keep all the BBC transmitters in Scotland on line and up to scratch (when they were valve receivers and transmitters) that every single thing in the circuit has an effect on the quality of the signal. He would know spending his working life fixing big hifi stuff with what was in the van as it were.

There are a lot of CCs in my 18 watt. I have no detectable noise from them. Whether they have a beneficial effect is totally subjective. But I like the look and I am happy with the tone I have. No science involved just lore.

They came by the bag load and I selected the closest values. But then I did have to swap out a couple when I had hiss soon after the build. So there is basis in the noise issue but it is not hard to resolve. And not all CCs cause problems. Except that in itself is a problem which commercial ampmakers have to consider. Whether you need or wish to bother is doubtful.

As a hobbyist I have time to take an empirical suck it and see what happens approach.

Dd

[JMPGuitars]

I just noticed that Danny Russell uses CCs in one spot only: the PI grid leaks. Hmm... Greta Van Fleet plays these.

Alice in Chains plays Meteopoulos, I feel like George isn't slinging "BS hype". He is a professional builder and amp tech. That said, I wouldn't use them in the input section where he indicates.

Who plays Keen's amps? I can't seem to find his builds anywhere.

This is a terrible argument. 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.

Jerry Cantrell plays Friedman, Marshall, Fender, and Mesa. And even if he does happen to own one of those Metro amps (which I'd be a little surprised) it doesn't prove anything regarding the position of CC resistors.

I'm a pro builder and an amp tech. That doesn't mean I haven't bought into any hype. It doesn't mean he hasn't either. Maybe he believes the hype, that doesn't make it real. A good build quality of a good circuit with good components will sound good regardless of the resistor type...though metal film might sound too sterile. Or is that hype too? I don't know, a lot of people use MF. Now I want to build an amp with mostly MF and see if I can tell the difference or not.

Here's Aiken's perspective, and certainly more on topic for this thread:
http://www.aikenamps.com/index.php/resi ... -it-matter
http://www.aikenamps.com/index.php/technical-q-a

Thanks,
Josh

[crgfrench]

Well, there you go. It's all subjective. That's why its art after all. Peace!

[JMPGuitars]

This is a good post on the topic:

https://music-electronics-forum.com/sho ... post304555

So much mojo in this subject matter, eh?

[crgfrench]

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.

I just couldnt help myself...
https://www.youtube.com/watch?v=w3XYb_SBWFo

[JMPGuitars]

I just couldnt help myself...
https://www.youtube.com/watch?v=w3XYb_SBWFo

Poor LedZep. Combining the lameness of GVF with Plant twirling his hair is...special?

[AussieTim]

Wow this has taken a turn for the weird which is OK with me, as the saying goes "when the going gets weird the weird turn pro!" and I can get as weird as anyone. Just ask my fishnet stockings
I think I have learnt what I have suspected and that is using carbon comp resistors is overrated and just like my analogy with tyres there are better modern types available. Lets face it we all love 57 Chevy,s but do you really want to lose your air-conditioning and sound systems with bluetooth, good fuel economy and comfy seats on your daily commute.
There seems to me to be a fine line between getting a good sound and hyperbole
I value all the inputs with this discussion and thank you all, i hope it will keep going and some more meaningful insights into resistors and their place in the soundscape of amps.
Long live Greta van Zeppelin, ill just keep listening to the old rock and roll and blues and drink whiskey {with pink lemonade told you I am weird}
Cheers
Tim

[crgfrench]

Jerry Cantrell plays Friedman, Marshall, Fender, and Mesa

Its William not Jerry. William's signature head.

[crgfrench]

Here's Aiken's perspective...

Highlight of Randall's conclusions:

"...it is better to use metal film for plate resistors."

[JMPGuitars]

Highlight of Randall's conclusions:

"...it is better to use metal film for plate resistors."

Specifically he's talking about noise. The thing that's easiest to gather from his perspective there is that he leans towards HiFi with his component choices. I am going to build an amp with all metal film to see how it sounds because I'm curious whether or not it will sound sterile compared to carbon resistors. I'm also curious if it really will sound cleaner than the modern carbon films I normally use.

[AussieTim]

HI Josh I look forward to seeing your results

[colossal]

I built a 100W three channel Plexi for a client once. This amp had metal film resistors and polypropylene signal capacitors throughout. The usual "formula" for a Marshall is carbon film resistors and polyester film foil signal caps. A mutual friend who I had built three Plexis for, swore this was one the finest "Marshalls" he had ever heard. He has no dog in the vintage part voodoo fight and wouldn't know carbon from metal film to look at or listen to. So he wasn't listening with his eyes or biased by preconceived, internet driven hearsay and so-called amp guru camp follower opinions. In my opinion, the amount of ignorance is superseded only by the sheer stupidity of some of the statements I read.

People often judge parts based on some divisive pedigree...either guitar amp or hi-fi, rather than looking at, understanding, and comparing the intrinsic properties such as dielectric, voltage handling, ESR/ESL, dissipation, etc. Hi Fi parts are often regarded by guitar amp people as some kind of cork sniffer exclusivity mostly because people cant justify the pricing. That's all well and good and there is certainly a marketing aspect to it which irks a lot of people, but that is beside the point.

A hi-fi part may be built to a higher degree of precision, and in small lots, which affects cost and supply. This doesn't make them inherently better or worse. Some people simply can't hear a difference in parts and therefore can't justify spending more than $0.03 for a Xicon carbon film.

Just some thoughts...not intended to inflame. These discussions often turn ugly and I don't know why. Use what you want. This is the art of building.

[JMPGuitars]

A hi-fi part may be built to a higher degree of precision, and in small lots, which affects cost and supply. This doesn't make them inherently better or worse. Some people simply can't hear a difference in parts and therefore can't justify spending more than $0.03 for a Xicon carbon film.

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.

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.

[colossal]

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".

[JMPGuitars]

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. 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

[colossal]

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. 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.

[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.

[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.

Dd