Cathode resistors for s.e.x. 2.1?

Jim R. · 1418

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Offline Jim R.

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on: August 10, 2016, 11:41:16 AM
So,  I'm going over my parts list and I'm curious what resistors are the cathode resistors for which section of the tube, and what are the changes one  may hear with a higher wattage rating, and non-inductive wirewound? No, I'm not ready to start in earnest -- everything is still in the shipping box -- but I'm starting to plan for the build, and whatever I can do to make things quieter (not that the ones I've heard were anything but very quiet) It's just that my main system is more quiet than any other tube system that I've ever heard, and I kind of like having no background noise I can detect, and think this would be an especially nice thing with  my cans, maybe even quiet enough for one pair of IEMs.

Thanks in advance for any guidance on this critical piece of the circuit.

-- Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline mcandmar

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Reply #1 on: August 10, 2016, 11:55:03 AM
The 1.27k are the cathode resistors for the preamp stage, and two of the large 680ohms resistors are for the driver stage.  Both are metal film.  For the preamp stage i don't think resistor noise is in anyway a concern, or even measurable.  I did replace mine with a 500ohm resistor and HLMP6000 LED in series which gives a slightly better high frequency response so if you are going to change anything i would recommend trying that.  All the info is in my rambling thread here http://bottlehead.com/smf/index.php?topic=5316.msg75855#msg75855

M.McCandless