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pjpoes 6th September 2005 02:17 PM

Alpha Ultra precision metal foil resistors
Hey I was wondering if anyone knew anything about these, had tried them, or even know where to get them. I dont even know what they cost. Of all things, I saw the add in stereophile and decided to check the site out and see. They seem in line with other similar resistors, like cadocks, wasnt sure if they were any cheaper or easier to get. Or possibly even of higher quality and better sounding. ???? Thanks.

jan.didden 6th September 2005 02:40 PM

There is a website but the pdf's seem to be dead:

Anyway, the fact that a resistor is very high precision has in itself no value in audio. Reliability may be a plus but that's difficult to hear ;) . Low noise would be good but I can't open any of the spec sheets.

Jan Didden

pjpoes 6th September 2005 02:44 PM

unless something just happened it was working for me. Thankyou, I had already found the sight. To be honost, my knowledge of how to read the noise level of a resistor in the specs is very limited. I have no background in electrical engineering or anything of the sort. In a psychologist with an intrest and a nack for soldering and breaking stuff. Thanks though.

jcarr 6th September 2005 04:26 PM

Alpha specializes in metal foil resistors, more along the lines of Vishay than Caddock. The resistance range is similar to Vishay (although they have more choices in low-resistance values), so for high-impedance designs, Caddock is a better bet.

Precision, noise tempo, and reliability are all quite good. Wide range of packages, too. Pricing similar to Vishay, perhaps a little cheaper AFAIR. All in all, not a bad resistor, not bad-sounding either, but not recommended if you are on a tight budget.

hth, jonathan carr

pjpoes 6th September 2005 09:16 PM

Thanks, I am not on a tight budget, but always like to find cheaper alternatives to a good product. I have never actually used Vishay's metal foil resistors. I had heard good things, but have mostly used the Vishay, Holco, etc. standard 1/4 and 1/2 watt resistors. I am just now starting to use some Cadocks in a few projects, and was considering the Vishays when I saw those. I was also looking at IRC metal film resistors from Handmade's store, they seemed to like them.

I know this is now changing the topic a little, but how do the IRC metal films hold up against these pricier choices? How about Carbon film and carbon composite resistors, like Stackpoles?

jcarr 7th September 2005 12:47 AM

I haven't used the IRC metal films, so I can't comment.

Carbon composition resistors are noisy, have a poor tempco (temperature coefficient), poor voltage coefficient, and some are hygroscopic, but they are non-inductive. Sometimes the non-inductive behavior is useful, but more often than not the drawbacks outweigh the advantages by far. OTOH, some people seem to like what a carbon comp does to the sound, and it is not my role to dictate subjective preferences.

Carbon films are quite variable, IME. Many have a poor tempco, , poor voltage coefficient, are noisy, have worse precision than a good metal-film, and more drift. OTOH, some (like the Rikens) are OK from an objective standpoint, and many builders who have used them seem to like the subjective results.

Personally, I haven't always had good results from el-cheapo carbon films. I've discussed some of my findings in the following posts.

hth, jonathan carr

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