Elekit TU-8200 DX Headphone/Speaker Amp Review
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dawktah2

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Grumble...

Crackle in right ear is coming back. Will open this weekend.
 
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Effusion

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@fide I wish I could help directly, however I haven't done the mods that @Dimu has to allow for those tube types. If you search this thread, you'll probably get a really good idea, or you could just send him a pm to find out more specifics.

@ctrlm, very cool, congrats on the amp and welcome to the club!

As far as output mode, it is probably best to try out each one in the end, to see what works best for you and your system. Personally, I prefer Triode with headphones, at least more than Ultra-Linear overall, but this also depends on the tube types you are running, as I prefer EL34s in UL. To me and with headphones instead of speakers, Triode gives me a bit more fullness/bloom, better soundstage, and a more relaxed/natural presentation, while UL is quite good in the highs, has great drive/punch, and overall higher gain. I have yet to really try the Pentode mode, was planning to do some testing weeks ago, but got caught up in other stuff, so I'll report back my impressions of this mode once I do. However, remember that each mode needs to burn-in a bit, in order to settle in, etc., so give each some time, like 20 hours or so, before deciding which mode you want to keep it in mainly.

Also, were the KT88s new production? Such as the Gold Lion or Psvane types? Just curious, I haven't tried either personally, but I've heard them at different events and in other 8200 units. I've liked the Psvane, however one amp running the new issue cheaper Gold Lions seemed too thin and a bit bright for my general tastes overall, but it could have been something other than the tubes in the chain causing this.

Cheers on the purchase!

EDIT: Just wanted to caution you when changing output mode types in the 8200. It is recommended to let the amp sit for 10 minutes unplugged before removing the case and changing the jumpers, etc. Just wouldn't want you to do any damage to it while testing out the modes, etc.
 
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ctrlm

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Thanks for the feedback guys! The KT88s are new production.

Unfortunately my unit has a 50/60Hz low level hum that is unaffected by the volume control. You can't hear it outside the unit, only through the headphones. I'm not sure if this is a DC offset issue or something amiss in the amp itself? So it looks it's going back to the dealer to be looked at next week.
 
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ctrlm

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I have a question about the volume level. It seems that 7:30/8:00 is fine for normal listening and 9:00 is very loud and distorted. Is this right? It seems strange that it would be this way with so much not being used.
 
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Effusion

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Not sure about the hum, as it could be a lot of different things, but it sounds like a ground hum from your description. So, you may want to try swapping out the tubes to see if it might be one of them causing any issues. You mentioned the extra set of KT-88s, but do you also have a different set of 12au7s as well? In my experience with the amp, sometimes the power tubes will hum and the signal tubes will hiss if they have a problem, so maybe try the stock again to see if it goes away?

Yeah, the 8200 has a ton of power! Just slightly below 9:00 is where I generally keep mine and even lower if it is loud/fast music in general as well, around 8:00. Several owners here have swapped out the pot for really good aftermarket options and have also put in resisters to get more movement control out of the pot. Maybe one of the users that did will respond, but you can also search this thread for some different options that have worked for others. I still use the stock option, but I am mindful of the extreme gain, especially when someone is trying it out for the first time and isn't familiar with the amp. I had a buddy that jumped on it during a meet without talking to me first, plugged in his HD800, put the pot to 12:00 and then hit play... wow was he surprised!!

:k701smile:
 
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ctrlm

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Not sure about the hum, as it could be a lot of different things, but it sounds like a ground hum from your description. So, you may want to try swapping out the tubes to see if it might be one of them causing any issues. You mentioned the extra set of KT-88s, but do you also have a different set of 12au7s as well? In my experience with the amp, sometimes the power tubes will hum and the signal tubes will hiss if they have a problem, so maybe try the stock again to see if it goes away?

Yeah, the 8200 has a ton of power! Just slightly below 9:00 is where I generally keep mine and even lower if it is loud/fast music in general as well, around 8:00. Several owners here have swapped out the pot for really good aftermarket options and have also put in resisters to get more movement control out of the pot. Maybe one of the users that did will respond, but you can also search this thread for some different options that have worked for others. I still use the stock option, but I am mindful of the extreme gain, especially when someone is trying it out for the first time and isn't familiar with the amp. I had a buddy that jumped on it during a meet without talking to me first, plugged in his HD800, put the pot to 12:00 and then hit play... wow was he surprised!!

:k701smile:
I still have the stock tubes in, it will be interesting to see if the new tubes solve the hum problem when they arrive. I have tried a lot of tests to see what could be causing it including:
  1. removing the signal tubes
  2. using a cheater plug briefly to ascertain whether or not it was a ground loop issue
  3. having no inputs connected at all
  4. trying different power outlets around the house
  5. turning off every breaker switch in my home apart from the circuit powering the amp and unplugging any other appliance still connected to that circuit
In all cases there was no change whatsoever to the hum which makes me fairly confident that it is the amp itself and (hopefully) just the tubes, rather than my mains power or an appliance plugged into it that is causing the problem. I know they are solid state but my Schiit Magni 3 and my old Musical Fidelity M1HPA are dead silent without a hint of hiss or hum.

The extreme gain doesn't bother me as it is still easy to find the right listening level, I just found it curious. It will make sure that I am extra vigilant before listening :L3000:

Thanks for your advice, it is very much appreciated!:thumbsup:
 
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Lasollor

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Hi guys!

I’ve been lurking in this thread for a very long time, this must be one of the most informative thread around here.
It was a tremendous help building my Tu-8200 about a year ago, so thank you!
It was my first build ever, I was learning how to solder on the way.
I did some upgrades later one by one, shamelessly copying Dimu’s build to a degree. (bigger rectifier to use E80CC tubes, volume pot upgrade to TKD, all resistor changed to ARMG, drilled holes for better cooling, Cossor 807 tubes, even hunted down the automative caps too).

Some of my experiences/failures:
  1. When I’ve tried to put in the bigger 3A rectifier, I messed up something, the amp flashed and smelled funny and never turned on again. I had to send it to Elekit, they replaced the transformer and redone some solderjoints. When I got the amp back I had low level hum I didn’t have before. I settled down on a 2A version witch is the same size as the original and it works well with the E80CC tubes. It was cheap, but I had to buy like 50 because that was the smallest available amount.
  2. Since the upgrade I only use the E80CC Valvo tubes, they sound similar to the Amperex 12au7 in tone but drive the output tubes with more authority. Downside for headphone listeners is that they have more gain. So if you already have too much gain, you should keep this in mind. I use Roon with -18db headroom, but 9 o’clock is about maximum I can go with the volume with my HD800 or HD650.
  3. I tried to get rid of the hum in million ways, but nothing helped. Until two months ago, when I finally replaced the volume pot and reheated some solder joints the hum disappeared from the left channel. Then I reheated most joints in the right channel too and no more hum.
  4. When I ordered the Amtrans ARMG resistors I didn’t noticed that they were not naked, which means the resistors arrived were 3 times bigger and it took a lot of time to find a way to fit them in. (And had to rearrange them later to fit in the volume pot.)
  5. I wanted to use triode mode a couple of times to lower the gain, but it always sounded very off so I went back to UL every time. I didn’t give it time to burn in though so I might try it again.
  6. The E80CC tube with GE 6L6GC and Philips 7581a power tubes in UL mode has way too much bass. I could enjoy this pairing. The 807 tubes are perfect with the E80CC. (the Sylvania 807s I have sounds good too, more similar to the Cossor tubes than not).
  7. The amp’s chassis and volume knob got very hot in the Japanese summer. After drilling some holes to get the air flow and using 807 tubes the chassis is only lukewarm even after 5 hours.
  8. For some reason the left driver tube socket rattles when I tap on the chassis. I couldn’t figure out this one yet.
  9. Cheap tube socket savers made the tubes rattle, better ones are silent.
  10. It seems to me that after replacing the pot with a TKD 2CP-601 50k pot, I have even more gain (or it might be just more clarity) than before.
  11. The Schiit Saga I have is not transparent enough to use it as a volume controll with the Tu-8200 and HD800/HD650, they loose some clarity and dynamics. It works ok with speakers.
  12. The gain switch on the back seems to effect the headphone out too. I suppose the higher gain applies less feedback, so it has more distortion, is that right?
 
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Dimu

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Hello all,
Dimu wrote about some upgrade of Elekit 8200 for using tubes E80CC. What did he tell about?

Thank you for advice.
All information is in this thread, repeated several times actually. It is related to heater current budget of the amp relative to elevated requirements of E80CC or 12BH7.
 
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Dimu

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I was wondering which mode people were using based on experience - Ultra-linear, Triode, or Pentode?
No need to overthink this. Just listen to music :)
My amp is set in ultra-linear as it feeds speakers most of the time. Good tubes will make a bigger difference than switching output topology.
 
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Dimu

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I did some upgrades later one by one, shamelessly copying Dimu’s build to a degree. (bigger rectifier to use E80CC tubes, volume pot upgrade to TKD, all resistor changed to ARMG, drilled holes for better cooling, Cossor 807 tubes, even hunted down the automative caps too).
Pictures or did not happen :)

Please feel free to borrow ideas, improve on them and share results!
 
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Dimu

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When I’ve tried to put in the bigger 3A rectifier, I messed up something, the amp flashed and smelled funny and never turned on again.
I have not done anything like this with my amp (yet), but have done it with other equipment powered by massive transformer and rectified with huge caps and then had to rebuild vaporized traces in the power supply. A wire hanging out or a careless move with a screwdriver is all it takes to short things. This is why I apply PTC thermistors to all power lines when I design my own stuff. Of course when you replace components that don't fit into allocated space you have even more risk so need to think through both electrical isolation and thermals.
 
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sunneebear

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Pictures or did not happen :)

Please feel free to borrow ideas, improve on them and share results!
Oh hell no! Everyone is getting a cut. I'm not saying it's a pyramid scheme, but it's a pyramid scheme. :grin:
 
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Dimu

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Oh hell no! Everyone is getting a cut. I'm not saying it's a pyramid scheme, but it's a pyramid scheme. :grin:
It sounds like you need to get busy rolling some tubes... how long has it been since your last roll? :)
I've been abstinent for a few months, already feeling itch creeping up.
 
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sunneebear

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It sounds like you need to get busy rolling some tubes... how long has it been since your last roll? :)
I've been abstinent for a few months, already feeling itch creeping up.
Mine has been MIA for a couple of months now.
On loan to my brother who just bought a pair of Zu Omens.
 
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Lasollor

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Pictures or did not happen :)

Please feel free to borrow ideas, improve on them and share results!
Unfortunetely I forgot to took pictures last time I opened up the amp, but I have some (bad) pictures from before:






 
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