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Best sounding resistors

I'm working on building another DIY preamp and am interested in opinions on the best sounding resistors, and specifically what sound characteristics you thought the resistors conveyed. These will be used in a balanced SS preamp with an op-amp based unity gain input buffer (instrumentation style) feeding a Khozmo shunt attenuator, with an output/gain stage using differential jfet input and single-ended class A mosfet output. 

I know there are plenty of people that think a resistor is a resistor and it's a total waste of money to buy "audiophile" parts. I have personally experienced a noticeable difference between various resistors, so I don't really want to get into that argument. And please don't ask about double blind testing or proving the difference with measurements. 

I'm particularly interested in your experience with the following types.

Amtrans AMRG
AudioNote Non-Magnetic Tantalum
Caddock MK132/MK232 thick film 
Riken RikenOhm carbon film
Takman REX carbon film
Takman REY metal film
Vishay Z-foil

I have some experience with the Takman and Vishay Z-foil resistors, and have already ordered a Khozmo attenuator with Takman REY shunt resistors. I will install the series resistors and am currently planning on Vishay Z-foil. The Takman REYs were Arek's (Khozmo proprietor) recommendation. 

My current preamp (DIY) uses mostly Vishay Z-foils and I do love the detail and airiness these provide, but the new preamp I am building requires a lot of values that are not currently available in the Z-foils. It also requires considerably more resistors, and the Z-foils are quite pricey. I am currently leaning toward a mix of Z-foils and Takman REY parts, but I'd love to hear about your experience and opinions.

Thanks,
Jay
128x128jaytor
pragmasi
212 posts
 
If money is no object then bulk foil are pretty unbeatable - however are probably not worth the expense across the board. The greatest benefit is the low temperature coefficient so worth it when they'll be dissipating some heat or near another component that will.
I use vishay thin film 0.1% as standard, they come in the e192 values so no problem with values up to 1MΩ and easy to find with 10-25ppm tempco.
If you're not already planning to do so then you might want to consider using multiple, parallel op amps in the input stage and going for the lowest resistor values you can get away with in the attenuator.  I'm currently using a 500Ω attenuator which will contribute around -128dBv noise... compared to a 10kΩ attenuator which would come out at around -115dBv.

jaytor's avatar
jaytor OP
742 posts
 
@pragmasi - Thanks for your response. I agree the Vishay thin films sound great. I am going to try to use these in as many places in the signal path I can. 

I am using the Salas DCG3 circuit for the output stage (in a balanced configuration) and this works best with a source impedance of 5K, so that is what I selected for my attenuator. But I am running fully balanced (two attenuator banks per channel), so this will help with the resistor noise. 

@petg60 - Thanks for the suggestion of Hifi Collective as a retailer. 
cal3713's avatar
cal3713
1,421 posts
 
@jaytor Did you see partsconnexion has a sale on Audio Note Tantalum resistors? I haven't heard them, but I see a lot of manufacturers advertising their use.

I haven't done good listening tests, but I chose naked z foil throughout the signal path of my amplifiers, vishay/mills non-magnetic wirewound in the high dissipation locations, and good ol vishay/dale RNs everywhere else. Not that any of those are news to you...

I'd hoped to compare a standard (First Watt F4) amplifier build to one with all those top parts, but also got talked into using different mosfets by Nelson Pass.  Unfortunately that made it so that there are too many differences to really pin down what makes the new boards superior.  They are way better though.
jaytor's avatar
jaytor OP
742 posts
 
@cal3713  the Audionote Tantalum resistors that are on sale are the magnetic variety. I've seen a few posts from people when I was researching resistors who tried those and were not happy. I think the non magnetic versions are supposed to be much better. Probably why they are phasing out the magnetic versions. 

I've ordered a combination of Vishay and Charcroft z-foils for all the signal path resistors and Takman REY resistors for the rest. Based on my experience with my current preamp, I'm sure I'll be satisfied with these. 
pragmasi
212 posts
 
I think it's worth pointing out that tantalum is a conflict mineral, something I didn't realise until a few years ago which led me to stop using the capacitors.
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