Replacement resistors in vintage equipment

I replace all carbon comp resistors I find with carbon films. Takman is a brand I like to use. I replaced all the carbon films in one Marantz 1060 amp with 1% metal films and left the carbon films in the second one. There really wasnt much of a diffefence Iin sound. There wasnt any hiss or sterile sound from the metal film amp at all, just a tad clearer sounding.
I did that, i dont know if you heard with vinyl, but for me, the sound of the two sides are very different. The resistors marantz side have more noise, but a open sound and smooth mids and highs. The takman film side has less noise, lack of dynamics and a harsh midrange. Marantz is known for his smooth sound, and i think the resistors have part of that.
 
I tend towards Vishay RN60, 65 or 70.

RN is my replacement-during-restoration series for standard wattage resistors, too.

Vishay's RN and RL series are the "military grade" versions of Vishay's CMF series, the precision, industrial, low noise, and flame retardant metal film resistors in their line up. Their SFR is their lowest "standard" resistor, their PRO1/PRO2/PRO3 series are their next-up high-power series, the CMF is the industrial low-power step-up to that, and the RN and RL versions are the better-standards versions of the CMF series. Well, as far as their datasheets say.

I did a simple, low-rigor comparison of the series available from Vishay to help myself choose which resistors to buy for which kinds of work (I'm just a hobbyist, but an OCD one) and here is the final section of the comparison doc I built for myself:

Price comparison
1K resistor lowest wattage & price at or above 250mW in each series

  • Vishay CCF 250mW $0.10 or $0.04/100
  • Vishay SFR 250mW $0.10 or $0.04/100 (low end standard)
  • Vishay RN 250mW $0.13 or $0.11/100 (mil-grade low noise, precision industrial)
  • Vishay CMF 500mW $0.14 or $0.11/100 (standard-grade, low noise, precision industrial)
  • Xicon MF-RC 250mW $0.17
  • Vishay PRO 2W $0.34 or $0.19/100 (higher power but standard grade)
  • Vishay CPF 1W $0.49 or $0.28/100 (high power flameproof)
  • Vishay PPF 1W $0.49 or $0.40/100 (higher power precision)
  • Vishay PTF 250mW $1.83 or $1.41/100 (high precision)
 
Suppose you were going to go through not only the power supply, but the amp driver boards in a 30 year old receiver or amp. You already have decided to replace the electrolytics and some other parts, check solder joints, etc. You want the thing to work reliably and sound its best for many more years, and so have decided to replace the resistors. All of them! Now, what type would you use? I have read many opinions, and some differ as to the type of circuit (i.e. amplifier versus R.F.). Anyone who has done this care to offer guidance? I should add that I am looking for that sweet spot of cost/performance, the most bang for the buck. Obviously, the largest cost of this is your own time. Many thanks for your thoughts!

A subject highly debated, and full of mis information from way to many who cling on to old crumbly carbon resistors as the standard, and think you have to cling to carbon resistors for that vintage sound.
Horse hockey (bs).

Here's a great statement:
"Standard policy is to use Metal-film resistors, and my preferred type is Vishay-Dale
CMF55 or CMF60 for 1/4W and 1/2W applications.
For higher wattage applications, I use Vishay-BC PR
01, PR02, and PR03 Metal-film types."

I have stuck to that for a long time and use ONLY the aforementioned in every vintage repair or restoration or anything else
with 100% satisfaction.
Ive got a audiophile ear and temperament and completely staying away from carbon, especially modern Chinese carbon
(used to be Japanese or Taiwan) is something that works.

If youre going to consider or debate cost, you can thank the Chinese for cornering the precious electronic metals and substances
market two decades ago. Vishay metal film cost what they cost.
 
I've opened up a lot of audio gear and noticed the majority (probably 100%) of the Japanese
units are carbon-filmed. I'd leave them alone and replace only those that are out-of-spec.
IMHO they are selected/designated for their contribution to the house sound. In those
brands where some of the great AKers do recaps (and leave the resistors alone), they
retain that sound signature. I think it's not mere coincidence.

My personal experience is recapping DH-101s (several) and the metal films lower the
noise floor and do change the sound for the better (wife says so).

I'd also spend whatever funds on better/refreshed caps. Another way the sound returns
to the design table.
 
I've opened up a lot of audio gear and noticed the majority (probably 100%) of the Japanese
units are carbon-filmed. I'd leave them alone and replace only those that are out-of-spec.
IMHO they are selected/designated for their contribution to the house sound. In those
brands where some of the great AKers do recaps (and leave the resistors alone), they
retain that sound signature. I think it's not mere coincidence.

My personal experience is recapping DH-101s (several) and the metal films lower the
noise floor and do change the sound for the better (wife says so).

I'd also spend whatever funds on better/refreshed caps. Another way the sound returns
to the design table.

Thats just the point about old vintage carbon- frying in heat for decades usually puts them all out of spec,
and hardly NO ONE checks every single old carbon resistor during a restore, recap, repair, or anything else.

Your wife is spot on- replacing the resistors with the metal films mentioned previously makes everything sound better, and I would argue from experience that
all vintage needs all the resistors replaced. The "vintage or house" sound only gets improved and everything runs cooler
and more efficient too.
 
Carbon films are/were used because they're cheap and ubiquitous, no other reason. I've almost never seen one drift or have any other problem, at least that was caused by the resistor itself. They're low noise and AFAIK, low distortion. I'd never change them out unless it was my own gear and I felt some need to go with all metal films, say in an RIAA section. Carbon composition is a whole 'nuther story. They're noisy and old ones go out of spec all the time.
 
I've had great luck with Xircon 1% metal films from Mouser. Sound is clean and it gets rid of the sometimes way out of spec carbons. Depending on the unit, sometimes those old carbon resistors are more then two times out of spec. I learned the hard way on a very difficult to work on preamp board. I had recapped the board and fired up the unit only to hear sounds that weren't on the record..... some of those resistors in the transistor biasing of the tone controls were so far out of spec I thought they were the wrong resistance. After restuffing the entire board it sounded fantastic. So now its a rule of thumb, the harder a board is to access the more components get replaced by default. In fact, now its just become a habit to replace all carbons and then I don't have to worry about loosing an entire stage when one of the old carbons flakes out.
 
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