Metal Film

[HobbswheresCalvin]

i would like to open up pandoras box and ask why no one uses these in their designs.

[diagrammatiks]

apparently ken didn't like them so the trainwreck amps don't use them.

lots of metal film over in dumble land.

[HobbswheresCalvin]

have to ask the almighty question....WHY?

[Cliff Schecht]

He said they were harsh to his ears. Many people have used them successfully in their TW builds, especially Dale RN65's. I used Xicon MF's in the past and did find them harsh but their cheapo carbon film resistors go in most every build I've done.

[Colossal]

I prefer and use metal films almost exclusively (unless an amp just has to have the very cool look of old Allen Bradleys, for nostalgia's sake). For practical reasons, I like the precision of metal films, the low noise floor, and the availability of high voltage and power ratings. I think the trick is to pick the right metal film resistor; one that sounds natural or does not color the sound. In a blind test of a modded Marshall I built for a client, the player said it was one of the warmest and best-sounding examples he has played. He knows nothing about resistor construction but he has played and owned dozens of vintage Marshalls. The amp was 100% metal film. Metal oxides were used in the power supply.

[mlp-mx6]

Colossal,

Which metal film resistors do you like in which positions?

Thanks,
Michael

[HobbswheresCalvin]

Thays good to know, i am thinking for my next build, using metal film at least for the plate resistors, especislly because of the low noise floor and precision.
Thanks colossal

[fishy]

Check this link out if you have not already....

https://tubeamparchive.com/viewtopic.ph ... ht=express

[Colossal]

Colossal,

Which metal film resistors do you like...l

I like Vishay Dale, Beyschlag, IRC-TT, PRP, etc.

in which positions?

Plate loads, grid stoppers, grid leaks (especially at the input), cathodes, and tone stacks too. Pretty much everywhere

[dorrisant]

I get nothing but good comments when I use Dale MFs in Rocket builds... trying them out in an Express build that should be done soon.

[leadfootdriver]

I read the interview where Ken said he didn't like them, so I used 1-watt CF's.

I did buy a bunch of 1% 2-watt 100K's that I'm curious about.

[HobbswheresCalvin]

thanks guys, i went with dales for this one, mostly. 1%s looking for a lower noise floor, also thinking of using sozo caps on this one too with f and t filters. i liked the f and ts last time.

[Colossal]

i went with dales for this one, mostly. 1%s looking for a lower noise floor, also thinking of using sozo caps on this one too with f and t filters. i liked the f and ts last time.

Don't expect that the Trainwreck hiss to go away or that the amp will be tomb-quiet. I think the sum of parts are important and everything makes a contribution albeit some small, and others larger. Metal films are excellent in the plate load position and input grid leak and I would say most especially on a Trainwreck amp where any noise at the input (or any amp really, but especially a Trainwreck) is there to stay so great care should be taken on V1 to reduce noise for the best result.

[billyz]

Where are you guys finding the Dale rn65 series resistors ? It seems most of my sources are drying up. Digi key and mouser are showing many values on backorder.
I did just score some nice IRC's though.

My experiments show that the good sounding ones are non-magnetic. test the cheap ones and you will find they are magnetic, ie steel leads and end caps.

[surfsup]

billyz, how do you test for magnetism with the resistor having metal leads?