Civilian 6n2+fu32 tube headphone amp
Jun 19, 2017 at 4:16 AM Post #106 of 115

borrego

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any one try upgrading transformers on this? or at least know the specs of the OT's and choke? the RCA 832a's sound really good and not broken in yet

The OTs are one of a kind with no other manufacturer makes. Specification is here: https://www.head-fi.org/f/threads/civilian-6n2-fu32-tube-headphone-amp.671419/page-3#post-10853175

Given the price of the amp, it does not have much economic sense to upgrade the OT and choke. You may want to try replacing the stock PIO coupling capacitors with Russian FT-3/FT-1 capacitors if you want more resolution, which can be done relatively cheap.
 
Jun 25, 2017 at 11:18 AM Post #107 of 115

hitchcaster

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The OTs are one of a kind with no other manufacturer makes. Specification is here: https://www.head-fi.org/f/threads/civilian-6n2-fu32-tube-headphone-amp.671419/page-3#post-10853175

Given the price of the amp, it does not have much economic sense to upgrade the OT and choke. You may want to try replacing the stock PIO coupling capacitors with Russian FT-3/FT-1 capacitors if you want more resolution, which can be done relatively cheap.

yes thank you... the amp is actually pretty high quality and a simple circuit... i put some mustard .33's in it when i first got it.. the stock caps are pretty goofy/cheap... volume pot is cheap so i upgraded that also. i was thinking of trying some u-caps since they are affordable vcap copies.. the russian teflons i think are good but ive never got them to beat high end caps made for audio, so id rather spend a little more when i consider those. interesting the OT's can't be upgraded.. thanks!
 
Dec 8, 2017 at 11:35 AM Post #108 of 115

MIKELAP

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If anybody is interested in buying the FU32-6N2 Headphone /Speaker Amp i have one for sale .It has low hours around 1 1/2 year old i also have adapters to use 12ax7 and 6sn7 tubes .Also i have 12 pairs of different brands for sale PM me if interested .Thank you 22860151_10214316067084887_6709968579229768139_o.jpg 22861482_10214316050764479_6189359045332536913_o.jpg 22861539_10214316177087637_6907603938524081184_o.jpg 22894356_10214316073165039_7892449789647703438_n.jpg 22904614_10214316177167639_8267692614592763615_o.jpg 22904620_10214316060444721_7954485705180252836_o.jpg 22904894_10214316069244941_7162131264531399900_o.jpg 23004788_10214316047364394_3739544541928115079_o.jpg 23116922_10214316063764804_3759960653658941456_o.jpg
 
Jun 5, 2019 at 9:02 PM Post #109 of 115

Origen Ru

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I just received the RCA JAN 832A tubes from vacuumtubes.net, replaced the FU-32s and listened for 3 hours. I have the Shuguang 12AX7M in the middle (like it better than the 50's GE 5751)


Did you clean the pins of the with RCA JAN 832A some jeweler's cloth to remove the black color (oxide) ?.
that black layer of oxide on the pins prevents the ideal performance of the tube, causing it to be immersed in the highs and dry in the low and mid, clean and listen to a big difference, greetings!

Initial Impression:

Compare to the FU-32s, the RCA 832A definitely gives better mid and treble resolution. The overall sound gives better sense of clarity. But the bass is definitely much weaker and loose. Leonard Cohen's vocal sounds 20 years younger. The RCA 832A also runs cooler compare to the FU-32, I suspect it will give less output power (it is common that Russia/Chinese copied power tubes usually can output higher current)

Depending on one's taste, can't really state the the RCA 832A is better than the FU-32 or vice versa. Please note that my amp is the "deluxe" version with larger power transformer which can better drive the FU-32s.

Will keep burning in those RCA 832A for another week and see if the bass will improve. Will also try pair the GE 5751 with it (but I already found the GE 5751 give loose bass, so might not be good combo with the 832A)
 
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Jun 5, 2019 at 9:17 PM Post #110 of 115

Origen Ru

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This is my Little Bear P32 which included a GU 32 Chinese tube.
20190527_152506.jpg

Replace the Chinese GU32 tube with the RCA CRC 829B and the OPAmp NE5532P with a Burson V6 Vivid, at first it sounded lacking in low and medium because it came with the black layer of oxide on the pins of the bulb, clean with a jeweler's rag for an hour until they were silvery and bright, I tried it and the sound is now magnificent.
20190603_154758.jpg
 
Sep 7, 2020 at 8:13 PM Post #111 of 115

MIKELAP

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This is my Little Bear P32 which included a GU 32 Chinese tube.

Replace the Chinese GU32 tube with the RCA CRC 829B and the OPAmp NE5532P with a Burson V6 Vivid, at first it sounded lacking in low and medium because it came with the black layer of oxide on the pins of the bulb, clean with a jeweler's rag for an hour until they were silvery and bright, I tried it and the sound is now magnificent.
How did that go replacing the GU32 by a 829B ? You can use that tube in your amp ?
 
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Sep 13, 2020 at 5:42 AM Post #112 of 115

Hal Rockwell

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I own the Little Bear P32 and decided to mod it with the 829B tube. It seems like 829B being a higher wattage equivalent of 832A. In any case, the pin-out is the same and the tubes in this amp run in starvation mode. I already own the Burson V6 Vivid. Lets see where it gets me.
I'm going to do additional mods too, like replacing the power button in the back, with a toggle switch in the front.
 
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Feb 23, 2021 at 10:02 PM Post #114 of 115

MIKELAP

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Also tried the 829b tube with A 6SC7 AS driver with adapters in the Civilian amp works nicely transformer temp is 50c after a few hours of run time
 

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Apr 21, 2021 at 12:40 AM Post #115 of 115

hitchcaster

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i have to switch mine to 120v for usa use... was using it overseas... anyone know where to get a PT with these specs or close that work? maybe a better PT would sound better then the cheap chinese one anyway... thanks!

Screen Shot 2021-04-20 at 8.57.46 PM.png
 

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