A potential resistor snake oil consideration for 2204 build

pjd3

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We hear a number of different opinions on components that differ and conflict wildly even among well known and respected builders and designers.
So, here is one of my trouble making never ending source of pissing contest generating ponderments:

I have a moderate supply of old Carbon composite resistors of various ratings and sizes (1/2W up to 5W and in between plus, a selection of old Mallory film caps in intermediate values, maybe .001uF up to .1uF and a few larger maybe.

My question is, for a 2204 build (with a few switchable mods for gain and eq) do you think there is any benefit to either using these NOS components or as well, Not using these NOS components? Sure, over time I am free to continue experimenting with all typs of components to see or, hear for myself but, I'm really just interested in your personal experience with this and what you have taken away from your trials with this. This 2204 build will really be focused on just copping a range of classic rock and hard rock pop guitar tones from the 70's and 80's for local small venue classic rock gigs. Thats all. Although many of the brilliant engineers and Zoll medical (I'm an R&D senior electronic tech there) have much to say about the different types of resistors and caps holding varying electronic advantages and disadvantages for different applications in circuits, they are not really able to comment on how this variety of component characteristics would manifest in a Marshall tube amp distortion/compression machine! We hear things such as carbon comp resistors having resistance coefficients with high voltage surges that many claim offer certain distortions that are desirable in guitar tube amps but, since I've not had personal A/B experience with this, I'd simply be very interested in what your experience has taught you, and perhaps that may inspire my to either proceed with, or omit certain types of components at least on the first iteration of this JCM800 2204 I"m right on the cusp of making.

Thanks everyone!
Best,
Phil Donovan
 

Pete Farrington

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I generally use recent production CC anode load resistors in the preamps of my builds, mods, repairs. Including last year’s build, based on a 2204 / Dirty Shirley preamp, into a JTM50 based power amp.
Unlike the Geofex article’s conclusion, I include their use on input stage anodes, as a reasonably high signal level there is likely even at low volume / gain settings. Whereas at a 2nd stage anode with a low volume setting, the signal level is likely to be lower than that of the input stage.

Whatever, I think they sound fine and there’s no noise problem. Though I’ve not done comparison tests to MF or CF.

My USB scope has a spectrum analyser, so I’ve been meaning to see if it can detect any difference between the types.
 

South Park

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The older carbon resisters have bigger leads easy to work with . As far as caps go use what you want I don’t think it makes much difference . The old stuff sounds good and the new stuff sounds good . It is all about the values of the parts that make the difference not what the parts are made of. What matters is the amp sounds good
 

Matthews Guitars

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Yes there are performance differences between carbon comp, carbon film, metal film, and metal oxide resistors. Those differences include not less than THREE different types of noise (Thermal, shot, and Johnson) which vary in level from type to type. And resistance values change with frequency. Any resistor can be modelled to include series inductance and parallel capacitance.

There are plenty of perfectly good, valid, and technical reasons why not all resistors of the same value and wattage rating are created equal. That applies to capacitors as well. Or really most any component.

We're not really talking about an "amplifier" in the formal sense, we're talking about a means of creating a desirable sound, combined with a good amount of volume amplification as well. What makes that sound so good is in part the specific idiosyncrasies of those components that do not have "ideal" real world behavior.

If you're seriously interested in finding out about these differences, I suggest you get or build a simple little amplifier built with point to point construction and use it as a test bed. See for yourself how the amp's noise floor and tone change when swapping from a carbon comp resistor to a metal oxide film resistor. Or replace a silver mica capacitor with a polystyrene type. And so forth.
 

SG-Rocker

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I converted an old 5010 SS combo into a 4010 (2204 combo). I used the tightest tolerance components I could find to keep the circuit as true to design as I could. I used metal film resistors everywhere. No regrets!

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Chris-in-LA

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I’ve built a few 2204’s, one uses carbon comp, the others use carbon film resistors. They all sound about the same. I’m my experience, your choice of output transformer might make more of a difference in tone than the type of resistor you use.
 

danfrank

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All Marshall amps, except for the very earliest ones, use carbon film resistors., Well except for the screen grid resistors...
CC resistors are noisiest compared to other types. The closer they are used in the circuit to where the input signal goes, the more this noise is heard. Current through the resistor also determines how much noise.
 


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