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vkung 28th January 2015 04:18 AM

Elekit TU-8500 Phono Amp
Elekit TU-8500 Phono Amp
Available in late Feb 2015
Another wonderful design from Mr. Fujita TU-8500 internal View

Stock tube: NOS 5965A X 2 (option :12AU7 x 2pcs)
OP-amp: NJM2068DD x 2pcs
INPUT/OUTPUT terminal: Phono IN x 1
LINE IN : 3 (3.5mm stereo jack(LINE3 priority) x 1)
Power voltage: AC100, 115, 200, 230V
IEC standard, 3P inlet
Rated current: 8W
Dimensions: W252 x H73 D270 mm
Weight: Approx.3.1kg (when assembled, excluding power cord)

[Line amp]
Max output voltage: 22Vrms (1kHz)
Gain: x3.1(9.8dB), x1.15(1.2dB)
Frequency response (-3dB): 2Hz – 70kHz / 2Hz – 280kHz
SN ratio(IHF-A): 122dB / 129dB

[Equalizer amp]
Cartridge: MM(Low) / MC(High) – Select by switching
Max output voltage: 7.4V rms (1kHz)
Gain (1kHz): [MM]37dB / [MC]63dB
SN ratio (IHF-A): [MM]108dB / [MC]88dB
Input resistance: [MM]50kohm / [MC]100ohm

Michael Bean 28th January 2015 04:34 AM

OK, where are the distortion numbers?


vkung 28th January 2015 06:50 AM


Originally Posted by Michael Bean (
OK, where are the distortion numbers?


we did not really measure the distortion.
But Mr.Fujita says that for preamp,the distortion does not really matter.
All the tube amps have distortion. We loves the distortion of tube amp

HeavyNova 2nd September 2019 03:16 AM

Hello! I am building this kit and have a question for you. The TU-8500 Japanese schematic says R55 = 3.3M, but the English instructions says R55 = 470k. Also, the schematic says R56 = 470k, but the English instructions says 10k. Which is correct? Thank you.

I looked at completed images of this kit online to try and figure out which resistors for R55 and R56 were correct. So I zoomed in on the photos and found around half of the build photos were unfortunately assembled incorrectly and show two different sets of resistors installed for R55 and R56 that nobody seems to be aware of. Which are the correct resistors for R55 and R56? Thank you.

vkung 2nd September 2019 07:21 AM

There are 2 versions of TU-8500.

HeavyNova 2nd September 2019 12:24 PM

OK, which is correct for R55 and R56? Depending where I look for instruction there is different information.

HeavyNova 2nd September 2019 01:04 PM

OK, thank you. I do not know which version I have, except to say I am building the regular 115V TU-8500 version, not a "SX" version, although from what I read about the deluxe SX model, it seems R55 and R56 would have the same values, except the fact they would be AMTRANS resistors instead.

I am still wondering which is correct for R55 and R56, do you know?

I have already switched R55 and R56 once after following the English instructions and then realizing the Japanese schematic it came with specified different values. My thinking was the original schematic it came with must be correct, right? Let me know which is correct, Thank you!.

WKCox 2nd September 2019 02:54 PM

Version 1: 470K & 10K
Version 2: 3.3M & 470k

HeavyNova 2nd September 2019 03:07 PM

Thanks! How do I tell which version I have? I don't see a mention of a Version 1 or Version 2 anywhere.

WKCox 2nd September 2019 03:15 PM

Should be on PCB. It seems you have tried both variation in your build. If so, how long was the muting delay in either case? If >15 seconds and <60 seconds you’re good to go.

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