What's the general consensus on Xicon Carbon Film resistors?

[Helmholtz]

Given the superior properties of MF resistors, does it really make sense to stock CF types for repair work?

[Enzo]

Some customers demand them. They might not even know what they are, but they have learned it is true to vintage...

[nevetslab]

Given the superior properties of MF resistors, does it really make sense to stock CF types for repair work?

Good question. In the case of Hiwatt, they have their fan base and devotion to how they've always built their products to guide what they do these days. That's kind of what shocked me seeing them changing to Xicon. Hopefully there won't be any difference. Selecting RN70 or equivalent, those do at least have a 500VDC working voltage rating, typical of 1W and 2W Carbon Film parts. 1/2W parts of any format are typically 350V rated parts.

[Helmholtz]

Some customers demand them. They might not even know what they are, but they have learned it is true to vintage...

Oh, I thought the hype was only for CC resistors which generate a little distortion at large signal voltages and technically are worst.

[Enzo]

That too of course.

[tedmich]

I highly applaud Nevetslab effort at quantitative measurement. There are many ways to be dogmatic... for a couple years the HiFi nuts thought metal foils should be everywhere, then the Japanese ~$30 each tantalum resistors were in vogue... although caps made from the same material have always been radioactive (except for certain vintage Mesas... ) maybe its thin films now?

[nevetslab]

Yesterday the Xicon RC Carbon Film 1W Resistors arrived to compare with the TE Connectivity CFR100 Series 1W parts like Hiwatt has been using in production. I also received fresh 500uF/50V Axial Electrolytic caps from Just Radios up in Canada to replace the aged 1978 Sprague Atom parts installed in the Quan Tech 2500's LV Power Supply PCB. Swapped those out first so I had fresh parts in that unit. I set up the Quan Tech for screening 100k resistors, following their Test Voltage = sqrt Resistor value x 0.25. 158V dialed in for the RUT value. Checked the System Noise, then checked the range I had dialed in for the average readings before for the CFR100's, 100k Carbon Comp along with 100k Metal Film. Substantially greater than the System Noise, but it did give me consistent readings. I went thru around 15 parts (out of a bag of 100 pcs) to see what the spread was. Those that read quieter I set aside for my low noise parts, those that read higher were set aside for the noisy ones. Found similar results with the CFR parts.

No big difference found on these typical plate resistor values for the Hiwatt amps. I wasn't able to purchase 220k's (no stock).. As I continued screening the lower values, I begin finding the nominal window was typically 7dB above the System Noise, so I begin setting the 5dB window based on 7dB on the noisier side, and 5dB less for the quieter side. That seemed to hold consistent with the parts I was measuring. Not sure why the 100k parts were beyond that.

I didn't find any large fallout on the noisy side of these Xicon resistors, no more so than that of the TE Connectivity CFR100 series parts. So, I guess just my years of unfounded bias about the Xicon parts can be put to rest.

Now....what happens with Production of Tube Amps with the present state of affairs on that dilemma.

[Enzo]

Many times I see folks who experience something and decide that therefor it is systematic with that thing. A one strike, you're out sort of thing. They got a noisy resistor and it couldn't be just a bad part, it must be that brand or model has issues.