[JK-47]

Thanks for the info Victor, but the TU-8500 capacitance is still a mystery....

 

[vkung]

hi JK-47
 
If you look at Audio Research Reference Phono 10 or other expensive phono amps, they  won't tell you the capacitance too. 
I trust Mr Fujita's design.  

 

[JK-47]

  hi JK-47
 
If you look at Audio Research Reference Phono 10 or other expensive phono amps, they  won't tell you the capacitance too. 
I trust Mr Fujita's design.  

 I don't doubt Mr. Fujita's designs, his Amps are awesome

 
I just wanted to be able to match my turntable cartridge, or future upgrades to the recomended values. My previous Schiit Mani had a capacitance of 100pF, and even with the wiring was borderline on the low end of the 150-300pF recommendation. More for piece of mind than anything else.
 
I will definitely be adding another Elekit amp in the future...300B.....

 

[vkung]

I will try one more time to ask him to let us know the capacitance . 

 

[JK-47]

  I will try one more time to ask him to let us know the capacitance . 

I think it's ok if he doesn't want to reveal the capacitance. His creations are excellent, and maybe that little bit of mystery adds to the magic

 

[vkung]

Mr.Fujita says there is no need to know the capacitance. He is guessing ....it is probably several pF at most.   

 

[mhamel]

 I don't doubt Mr. Fujita's designs, his Amps are awesome

I just wanted to be able to match my turntable cartridge, or future upgrades to the recomended values. My previous Schiit Mani had a capacitance of 100pF, and even with the wiring was borderline on the low end of the 150-300pF recommendation. More for piece of mind than anything else.

I will definitely be adding another Elekit amp in the future...300B.....

I'd love to see a version of that 300B amp with a headphone out. I was thinking of buying one and building an adapter when I bought the 8200 kit.

 

[LingLing1337]

Looks like the speakers im using are 88db sensitive @ 4ohm. The little tu8200 kicks ass but I'm going to get a powerful solid state to compare.

 

[vkung]

You need to compare the clarity..

 

[lucidreamer]

Hi everyone,
 
I just got my new Elekit TU-8200DX tube ampflier kit (with upgrades) built last Friday after it arrived from VKMusic.ca. Victor shipped it on Monday and it just took 5 days travel from Vancouver, BC to Florida which was pretty quick. It took me around 12 hours from start to finish, since I wanted to make sure everything was right before soldering it to the board.
 
Victor from VKMusic.ca is a fantastic person to deal with all the time, very supportive and enthusiastic about his audio stuff! I had a pleasure to talk to him on the phone a couple of times to discuss the possible upgrade options, some tube choices, and so on. When I sent him an email with some questions, he responded almost instantly which was not something you would get these days (unfortunately). I would highly recommend VKMusic to anyone (with some basic electronic DIY skills, of course) who is looking to build a great tube amplifier at a very competitive price but still weighs all the risks associated with doing it by oneself using a kit or buying a ready to plug product. Well, there are lots of great commercial tube amps on the market but, in my mind, this Elekit one has definite advantages over many of them that cost much more. Even by looking at its schematic topology and choices of parts proves it immediately. The Japanese quality is top-notch and the steps in the manual are perfectly detailed. The amp is pretty easy to take apart for upgrades and service, if needs arise, it has all the modular design with Molex connectors and does not require any soldering to take it apart completely.
 
I was really surprised by how good it sounded even with the stock 6C6EH power tubes before any burn-in took place. The sound is very balanced and detailed, there is plenty of bass as well, that I was afraid to be lacking before, but I was mistaken. It is not bass heavy, rather very pronounced and reference-like, very dependent on the source quality too. I cannot comment on the stock tubes sound since I currently have only the stock ones, once I will get the upgraded tubes, I will be glad to compare them with these ones that came with the kit. However, those ones are sounding great to my ears as well.
 
The aluminum volume knob has a little hole in it to insert a regular led light and some recessed area to store the wire for supplying the (+) voltage to the led after another 10k ohm resistors soldered to R62 leg. I think it looks cool to complement the amp with the lighted volume knob as well as making it practical to easily to adjust the volume at total darkness. It is super easy to do too.
 

 


 

 

 

[JK-47]

Welcome to the club lucidreamer!!!!
 
Great mod on the volume knob

looks sweet.
 
I saw a the same mod on a different Elekit amp on another forum, and it's nice to see it implemented on our amp.
 
Keep us updated on the tube rolling

 

[lucidreamer]

  Welcome to the club lucidreamer!!!!
 
Great mod on the volume knob

looks sweet.
 
I saw a the same mod on a different Elekit amp on another forum, and it's nice to see it implemented on our amp.
 
Keep us updated on the tube rolling

Thanks JK-47! I am hooked on the tube sound already (actually from childhood) and will definitely post my thoughts on various tubes later on... I already have a pair of Psvane KT-88 and 12AU7-T MKII tubes on the way, but it may take a few days to arrive from overseas.
Yes, the volume knob had a space for the light already and it was just perfect to fit a regular size led that I took out from a cheap flashligh toy that ran out of batteries and was abandoned by my son Looks like he dropped the flashlight into water or something, since the wire leads had some corrosion on them. I used some electric liquid insulator paste to secure the led and prevent the light from leaking back into the amp box. Initially I put a 1.37k ohm resistor and it was super bright, almost turning a volume control into a headlight, which would be a overkill for its purposes and too annoying during nights. So I took the amp apart and replaced the resistor with a 10k  one which is perfect and should keep the light from burning out faster. Inside the light hole I put a small optical plastic rod machined from the piece of clear plastic from the external hard drive enclosure that had a drive failure lately. The plastic sent the light from the harddrive PCB to the front of the enclosure. After machining the tip to a round shape to fit in the hole it sticks out a little bit and looks better to me than just a simple empty hole with a light in it. I think any piece of clear or other colored acrylic should work just as well.
 

 
Maybe worth mentioning something else...  those who plan to buy and assemble this amp should have decent soldering station in place with fine point soldering tips handy. There are some tiny pins to solder for multiconnectors to the board with their pins standing 1 millimeter apart!! I also bought the following great tool on Amazon to secure the PCB board and allow it to flip 360 degrees. It would be a royal pain to do it without it:
http://www.amazon.com/gp/product/B00Q2TTQEE?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00
 
A nice pair of breathable electronic gloves like this is nice too:
http://www.amazon.com/gp/product/B00880BB9S?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00
 
I used a 4%-silver bearing German-made quality solder everywhere too. Another type of solder that I used before already turned greyish, but this one is still shiny clean on the PCB after 15 years!!! It has a flux mixed into the lead and after completing the board - I ran a toothbrush soaked with alcohol to remove as much flux as possible. Not sure if flux has any effect on the sound quality, but it is just a good practice to make sure that no small soldering particles are loose after the work is done to prevent shorting the parts.
The transformer sends 300 volts to the tubes, it is quite high voltage and should be taken seriously.

 

[lucidreamer]

I am just curious if it is normal that the whole metal chassis case getting pretty warm after a short while when the amp is running? I mean it is not too hot to the touch but is pretty warm let alone the tubes which are actually hot. I believe it should be normal, since the tubes emanate heat that is dissipated and evenly distributed by the metal case but I just wanted to double-check.
When I first assembled the amp, I let it run for a few mins only to make sure there was nothing wrong with it, like excessive heat, smoke, etc. or the transformer making noises. Then I put the case on. I should have probably tested it for a hour at least without the case to make sure no parts get overheated or something (except the tubes, understandingly). In my experience, if something is not done right, it may still work ok, but some components may be overheated and burn out quickly.
 
Thanks.

 

[JK-47]

  I am just curious if it is normal that the whole metal chassis case getting pretty warm after a short while when the amp is running? I mean it is not too hot to the touch but is pretty warm let alone the tubes which are actually hot. I believe it should be normal, since the tubes emanate heat that is dissipated and evenly distributed by the metal case but I just wanted to double-check.
When I first assembled the amp, I let it run for a few mins only to make sure there was nothing wrong with it, like excessive heat, smoke, etc. or the transformer making noises. Then I put the case on. I should have probably tested it for a hour at least without the case to make sure no parts get overheated or something (except the tubes, understandingly). In my experience, if something is not done right, it may still work ok, but some components may be overheated and burn out quickly.
 
Thanks.

 
My Elekit get's fairly warm to the touch too...

 

[lucidreamer]

Thanks JK-47. I also figured it was pretty normal for tube gear to get that warm. I may also consider building a metal protector enclosure for tubes or some sort of tube guards to prevent touching the tubes by accident, with small kids running around, you never know.
 
Another thing I am a little confused is whether I should use the stock power cord that has a lifted ground (green wire) or replace it with a regular 3-prong heavy duty (15A) power cord that I have in stock. I used the 3-prong and did not notice any hum or noise compared to the stock cable. However there are some reports online about this amp where switching to the 3-prong power cable added more noise/oscillations caused by the ground loop. Switching back to the stock cable fixed the issue:
 
http://www.6moons.com/audioreviews2/elekit/2.html
 

The power cord that comes with the Elekit is a two-prong plug with floated ground wire that looks identical to the one for the  

Triode TRK-3488

. I learnt my lesson last time where floating ground silenced hum. It took me no time to reconfirm that on the Elekit. I compliantly replaced the more expensive three-prong power cord with the humble-looking stock.

 
In the TU-8200DX manual it is recommended to attach the ground wire to the electric outlet if it does have a ground terminal on it. But here in the US all the 120v household outlets already have 3 prongs anyways. Why not replacing the stock one with the 3-prong cord then. Did anyone notice any issues after trying the 3-prong power cord by chance?