Elekit TU-8500 Phono Amp

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Elekit TU-8500 Phono Amp
Available in late Feb 2015
Another wonderful design from Mr. Fujita
www.vkmusic.ca/TU-8500.htm




http://youtu.be/wGnKvAtc0Rc 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)
PRE OUT 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

 
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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.
 
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!.
 
Here's all I could find. Is "MP02" Version 2? I am really excited to get the Elekit built. I've heard some very good things about it and the downloaded English instructions have been very, very good otherwise and was only missing two resistors which also gave me an excuse to order other upgraded parts for it as well including vintage polycarbonate, polystyrene and MKT1822 caps, gold plated Mill-Max opamp sockets, as well as Shuguang 'Sounds of Nature' 12AT7's.


The Nichicon HV/VY and polymer caps it comes with are very good and hard to beat in most specs. and locations. However, I'm going to incorporate 4 Elna Silmic 220uf 35V that tested lower ESR than the (4) 220uf 25V it came with and hopefully try the recommended opamp upgrade as well.
 

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I finished building my Elekit TU-8200R and I'm planning to build an Elekit TU-8500 Preamplifier. What is the advantages of using the input of TU-8500 preamp for my sources rather than connected it directly to the input of the TU-8200R amp is there an improvement of sound if using a preamp?
 
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(...)What is the advantages of using the input of TU-8500 preamp for my sources rather than connected it directly to the input of the TU-8200R amp is there an improvement of sound if using a preamp?

If you are not planning on using more than two sources then there isn't any benefit other than the phono stage. You would end up with two pots, and there are are least two threads on this forum asking how these should be set.

The TU-8200 is sensitive enough for all normal sources. Also note that the TU-8500 inverts signal polarity. Whether or not you can hear this, that is another question. It is easy to swap loudspeaker connection polarity, but the headphones are a different story.

If all you need is the phono preamp then you may consider building the Sunvalley kit instead. It has relatively low gain, but still fairly enough.
 
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