Elekit TU-8200 DX Headphone/Speaker Amp Review
Jun 15, 2014 at 1:54 PM Post #16 of 1,441
Great review.
I heard this at a local Vancouver meet and was amazed by the musicality of it. First listen, the music sounded extremely warm and inviting, drawing you in. Victor was playing CDs with this 47 Treasure CDP through the amp and driving a pair of HD650s. I'd be pretty happy with this combo and not want for more. 
Jun 15, 2014 at 4:30 PM Post #17 of 1,441
If the TU-8200DX really does pair well with headphones of lower ohms, it would be very cool.  I do plan on obtaining at least 1 new headphone in the next 6 months, but probably either a medium or high ohm model, so we'll see.  As far as something like an IEM, which I personally would never use with this amp on purpose, I'm not too sure... might be some hiss; it would be quite the feat if it did though!
It's nice having someone like Victor so close, as shipping and import is much cheaper.  I wish it was a little more feasible for you, as it is a very nice amp.
As far as tube rolling differences, I actually mean both differences, between variants and brands that are both more impactful; however it comes in varying degrees of impact, so it would help if I clarify.
An analogy of these differences I could try to use, would be similar between different types of cable changes, where some can have more of an impact than others seem to.  I would say that the differences in brands, but same make of tube, are generally much more subtle than differences between different labeled designs.  Such as the differences one might find between 2 really good RCA cables of similar material.  While the differences between actual variants is more discernible and I find is easier to detect.  More of like going from the stock power cord to a nice high end power cord of good quality materials.  I would say that I've found the effects are generally twice to close to three times as impactful between variants than between most brands of the same.  Of course, everyone's mileage will vary by system and I've also not not always found this to be the case; the automatic bias feature of the TU-8200DX does make auditioning these many variants easier.  However, the sound quality has always been very good with the tubes that I've tried so far, just interesting alterations between them, that I believe is due to the greater resolution of the amplifier when compared to the 336se.
There are a ton of tube-rolling threads out there over sonic differences between brands, but I've often found that it is best to let my own ears decide sometimes and will try any manufacture at least once.  I do believe that everything from the materials used, to the fitting of the factory, and especially design can lead to differences in characteristics; how small vs. big these differences are is dependent on many things.  There are a ton of ways manufactures designed their tubes in the day, even within the same family/brand, usually at least distinguishable by the years of production.  Some specific factories, such as Mullard's Blackburn, tend to give more resolution/detail than Mullards made elsewhere, as their factory in India.  Everything from plate structures to getter shape/location all seem to have an influence on the signal, I guess it makes sense, since the tube is in the path of the music.  If this wasn't the case I've found, my wallet would be a lot happier! :)  There would also be no need to switch out the stock tubes, or run a Bendix 6080WB or GEC 6080, rather than a GE 5 Star 6080 or run of the mill RCA, which in my opinion can sound very thin often.
As far as the impact between rolling the 336se to the TU-8200DX, I believe what I'm hearing is partially due to the better separation between the channels in the TU-8200DX.  That the added silence, detail, and resolution from the Elekit has made the sonic differences more distinguishable than before, at least for me.  At times, it has made me wonder if I was ever truly getting all the differences between the different brands/designs of 6SN7s in my 336se because of some congestion/bloat.  I never felt much congestion nor bloat with all of the tubes I've tried so far in the Elekit, unlike a few with 336se.  Also, during the burn-in period these differences were much more pronounced and since have smoothed out quite a bit; blending in better and are now a little harder to pick out.  I use a selection of 15 to 30 seconds clips that focus on some of the sonic aspects the tubes seem to impart on the sound; some show me lower mid-range resonance levels, while others sound stage/imaging, and even a few I use to test high frequency, such as the crispness of a cymbal crash and the layers of resonance that follow; I also find that even voices are very good for testing.  Over time, consistent use of these test tracks has given me a better baseline to judge between various brands, which isn't always an easy thing to do.
I have spent some time with 6AS7G/6080/5998, as it is the power tube in the 336se as well, but unfortunately there isn't huge copious amounts of different types of this tube to roll out there; there are still a few though.  The 6AS7Gs are almost all RCAs, with a few being made by tungsol/chatham for military use.  There is a small difference in the mids/bass between the black and gray plates, with the gray plates being a little softer around the edges with better mid range and sound stage; the black plates are older with silver lettering, while the more recent production gray plates have orange lettering.  I find that the bass is somewhat lacking on the gray plate RCA, with the black having better weight.  The 5998 is almost exclusively Tung-sol with re-brands by Chatham, which I find is more in line with the sound of the 6AS7G than the 6080, but with deeper bass, extended highs and more weight to the sound.  It is hard with the 5998s, as they also give a bump to the overall gain, so everything is more pronounced unless adjusted.  The 5998 are great for slam and dynamics, but lack overall air and depth many times, IMHO.  I find that neither of these can touch the sound stage and air of the 6080 though, with an exception maybe with the RCA gray plate.  I do find the 6080s to be more polite, but with added air as well as bloom, if at the expensive of slam and weight, especially compared to the 5998.  You really have to be a little careful though because I've found that several brands/batches of 6080 are a little light in the low end.  I've never liked the GE 5 Star and RCA (except for older JAN RCAs) for this reason, and while the Tung-sol and Bendix WB build with cast iron plates can give nice highs, great mids, and enough bass for most music, at times they can sound a little thin in the upper mid-range.  For 6080, I prefer the mids and extra airiness from the European variant, the CV2984, with Brimars and British Military being very nice if you can find them.  Then there is the GEC 6AS7G, with comes as a coke bottle as well as a 6080.  I purchased one about 5 years ago for a great price, at $80 shipped NOS, however it was damaged in shipping.  Supposedly they have the same internal structure, but the coke bottle 6AS7G generally commands higher prices.  I wish there was a little more variety with the 6AS7G type, but the 6sn7 is truly a monster when it comes to different brands/builds and one of the main reasons I bought the amplifier and have kept it for so many years.
The 6sn7 has a ton of brands/designs, which makes it a favorite tube of many rollers.  Within the 6sn7 type there are different designations separating designs by the addition of functionality and/or purpose.  Some have heaters and warm up quicker for example.  While there are differences between these types (designations GT, GTB, A, W, etc.), different brands/years used not only different components/designs, but also different materials.  All of this can affect the sonic characteristics of the sound, but I've found that price isn't always a true determinative value of quality; like a lot of things.  Many tubes that I purchased on the cheap have really impressed me, at least in my system and to my ears.  Some are definitely worth their money, such as the Tung-sol Round Plate, or the metal based and plastic short bottle 6SN7W, which can really go for a lot.  However, others such as the early Hytrons/CBS, or the militarized micanol bases can be had for cheaper prices and still sound very good.  For example, one little generally unknown tube, the 60's Brazilian Aluminum RCA 6sn7gt, is very different than any other 6sn7 I've tried, closer to the Tung-sol "Mouse Ears" than anything else, but still very different.  This Brazilian metal design can add a ridiculous amount of air and seems to push the sound out in all directions by many feet; very good with chamber/orchestra and even live acoustic.  Then there is the European variants like the CV1988 and B65.  I've never had the pleasure of trying a B65, such as the Osram/Marconi brands, as they can be very expensive.  I do have a Brimar CV1988 black glass that has very good mids, but seems to cut off too much of the highs and also be a bit sibilant.  Others can work in place of the 6SN7, such as the ECC32 and ECC33, in most applications, with more impactful differences than within same family.
The 6AS7G/5998s really don't have a whole lot of different manufacturers out there, at least compared to others, there is more as a 6080 variant, but still not a ton.  On the other hand, the 6SN7 is a widely popular tube, even during it's day, and was made by many different manufacturers/brands, which in most designs/brands provides enough variation to warrant large tube threads/discussions/rollers, not to mention the varying degree of prices asked for on-line and in auction.  However, I do believe everyone's mileage may vary as ears and systems are different.  There are also a lot of re-branded tubes that not only sound exactly like their OEM brothers, but because so generally go for cheaper prices.
As far as the TU-8200DX, there are a ton of different actual variants of tubes you can use, regardless of brands, and the differences between them are not always subtle at all.  The KT series sounds very different to the EL34, or even the 6L6CG.  However, at times I've found differences even within manufactures, with the blue glass Telsa EL34 being much brighter up top with great air, but a little thinner and lighter in the low end than the Tesla yellow seal clear glass.  GE and RCA 6L6GCs are similar, but the GEs tend to have quite a bit of bass compared to the RCA, which I found is more balanced, similar to the 5998 and what it does to the speed and articulation of the notes.  Within these types there are also many new production tubes, some of which are really only geared to guitar amps, which can really eat up tubes during live shows.  Since they are constantly going through them, they need more inexpensive new production brands.  Most of the time these are Russian, such as Svetlana's, JJ's, or the re-branded Tung-sol's.  Others such as the Russian re-brand of Genalex's Gold Lion brand give better sound quality, but at a higher price.  Russian manufacturers bought the rights to use the names of classic out of production NOS types, building them to the specifications of the original designs (or at least they claim).  However, many believe that most of these do not sound as good as their original NOS counterparts, and the cheaper brands aren't seen as reliable.  Many like the Russian Gold Lions, as an inexpensive alternative to the NOS original.  The KT88 GEC's or original Gold Lions can bring large prices at $200-$300 a tube, which is a product of both their scarcity and sonic enhancement; arguments for both. Other new production, such as Psvane and Shuguang Treasure ask higher prices for claimed higher fidelity; many have had great results.
There are also many variants for the 12au7 and even more brands, which can either be dirt cheap or command very high prices.  With the TU-8200DX, I find that the differences between signal tubes can vary from subtle to slightly impactful, with again the more impact coming from variants than individual brands.  The Tung-sol black glass provides a very nice full sound, while some of the GE's can sound a little thin.  I've also enjoyed the CBS/RCA black plates, with the RCA clear glass being very clear and detailed, but a little thin with certain songs.  Then there are the variants, such as 12au7a, 6189, 5963, 5814, 7730, 6680, ECC802S, 7136, ECC82, 13D5/4/8, and probably a lot more I missed.  Within a few of these variants there is only really one brand, sometimes with a few re-brands, but generally the 12au7, 12au7a, 5814, and ECC82 have quite a few brands.  Another example, I've been using some Tesla silver pin ECC802S recently and rolling Siemens, Valvo, Mullard, and Philips EL34s; I'm getting some really great smooth detail with great clarity in the mid-range, very nice.  There are the more expensive Telefunkin gold pin ECC802S, that are supposed to have better clarity, but only these two brands.  While the different brands of EL34s listed all have varying degrees of detail, air, and sound stage in the mids/highs, but not huge differences.  So, a bigger impact to what I'm currently hearing would be to change to say a KT88 and a Mullard Blackburn ECC82.  I believe this is due to the increased resolution of the TU-8200DX over the 336se, as the differences between these similar EL34 brands seem to have more of an impact than say a GE 6080 5 Star gray plate and an RCA orange label black plate 6080.  Now, putting in a Telefunkin EL34 or a SED Winged "C" or even a Groove Tube, will give me a more intensely different flavor.
From my experience, I would say that it depends on the types of tubes used and the resolution of the amplifier in the end, which both are a testimate to good design.  Some designers have chosen to go with newer production tube implementations, utilizing new production Chinese and Russian types, while others have kept the NOS market very much alive today by choosing types such as the 6sn7 and 6AS7G.  With a ton of NOS options as well as plenty of new production today, I'm sure glad Mr. Fujita picked the ones he did for the TU-8200, even though my wallet may not be... 
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Jun 17, 2014 at 7:46 PM Post #18 of 1,441
  Great review.
I heard this at a local Vancouver meet and was amazed by the musicality of it. First listen, the music sounded extremely warm and inviting, drawing you in. Victor was playing CDs with this 47 Treasure CDP through the amp and driving a pair of HD650s. I'd be pretty happy with this combo and not want for more. 

I think I remember Victor telling me about that meet, right around the time my FET went out.
I agree, the 47 Treasure CDP really sounded good.  I wish I knew more about the DAC inside; Victor did mention that it was more of an advanced build and it does look a little complicated.  Very cool design and sounded amazing when paired with the TU-8200 and running HD650s.
*EDIT, added some pictures of the 47 Treasure below from RMAF, the second picture it is next to the TU-8200, with my HD650's plugged in... the CD spins outside of the unit, very different/cool design that sounded very good with this combination!

BTW, really enjoying a nice pair of KT66 IEC Mullard Clear Glass with Tung-sol black plate black glass 12au7 with both rock as well as piano right now.  Very nice speed, depth, impact, and tone, with just a little sparkle in the highs, I believe due to the tung-sols.
Jun 20, 2014 at 4:55 PM Post #19 of 1,441

For the TU-8200 the headphone circuit is not exclusive and does not bypass the tubes or output transformers. Mr. Fujita our chief designer simply made the headphone terminal an integral part of the tube amp itself, adding only three pairs of resistors to the signal path.
Jun 25, 2014 at 3:15 PM Post #21 of 1,441
The size of  1/w Amtrans  carbon film resistor is bigger than stock 1/2w metal film resistor.  To replace the existing 1/2w metal film  resistor with Amtrans carbon film resistor, you will need to adjust the angle of the Amtrans carbon film resistor to install it on the PCB. This picture shows how it should look once bent and installed properly.

Jul 1, 2014 at 6:15 PM Post #22 of 1,441
Elekit does not recommend adding a switch to change the output mode.
Changing the output mode while the power is ON could damage the tubes and output transformers.
Photos are from the following link: The site administrator has a lot of  interesting ideas to modify TU-8200



The following are photos are from 6moons TU-8200DX review


Jul 7, 2014 at 10:11 PM Post #23 of 1,441
Thanks for the link!
Very interesting modifications, but as Victor points out you need to be careful to not change the jumpers while the amp is turned on.
Although the different output modes is a really cool feature of this amplifier, I think it is probably best to stick to one output mode depending on your tastes as well as the sensitivity of your speakers.  Since the review, I have played around a little with the Ultra-linear mode and while I've found it to have a very nice sound/tone, the rolling of different types of tubes has given me more of a change, allowing the tweak-ability of different sound signatures that I enjoy.
Still a very interesting modification and site; too bad I don't know Japanese! 
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Jul 19, 2014 at 12:30 PM Post #26 of 1,441

Finally, I installed Amtrans AMCY Oil coupling caps with TU-8200.  This is the joy of DIY. You can improve the sound at your discretion and budget. 
 If you have a bigger budget you can use Amtrans AMCA (copper foil  $60 each ). I think the AMCY ($25 each)  is good enough for TU-8200.
I will attend the SFO Audio show to spread out this JOY.  You don't need big money to have excellent sound
Please trust your ear rather than reviews. DIY is my passion..
Sep 4, 2014 at 1:31 AM Post #27 of 1,441
For those who’ve wondered about the Elekit with lower impedance headphones, here’s my experience with Grado GS1000i’s:
After reading Effusion’s review of the TU-8200DX, and some of the others on the web, I decided to take the plunge and build one of these. I’ve done a fair bit of DIY electronics work in the past but hadn’t had the soldering iron fired up for a while, so the chance to build an amp myself, have some understanding of the circuit, and be able to tweak it a little if I wanted to appealed to me.
I built it over a several sessions, but I’d say it only took about 6 hours from start to finish.. and when I first fired it up with the supplied tubes (no-name chinese 12AU7s and EH 6L6GCs) in Ultra-Linear mode, I’m glad to say everything worked and I was impressed with what I heard. It was detailed and warm, with the bass response notably deeper and fuller than I’d heard with other amps.
I found out fairly soon that with the Grados at the levels I like to listen, the bass was just too much and I couldn’t listen for long. It sounded great, but my ears couldn’t take much of it. I switched to Triode mode and things got better, and also tried a pair of PSVane KT-88s, but for me the bass was still overwhelming everything else a little.
Next I went on a bit of a buying frenzy with the 12AU7s and rolled a heap of different brands and types through (I’ve got Amperex 7316s in there now.. a great choice if you can find good ones). They all had their own sound but they didn’t change the basic character of the amp. Then I decided to try some EL34 power tubes, not expecting anything much, but what I got was a major transformation. Suddenly the bass was perfect, plentiful and dynamic, but no longer “too much” for comfort.. and without the bass taking the main stage, everything else came to life. I could hear every detail, vocals, cymbals, guitar, everything sounded balanced, detailed and lively without a hint of harshness. The soundstage, which was already good, opened up even more.
I’d say all this detail was there before, but the bass was dictating the volume and so the mids and highs were effectively turned down.
In hindsight, the answer was there all along, and if I’d bothered to read the original post by ‘Effusion’ a bit closer, he’d already laid it out when he said: “If you tend to find yourself opting for less bass in your listening preferences you can try a pair of EL34s for some extra mid-range detail”… and, “I have found that EL34's tend to be a little more shy when it comes to the bottom end than KT88s or KT66s, however they have a beautiful mid-range and probably the best sound stage out the variants I've tried thus far”.
The GS1000i’s have that boost in frequency response at around 100Hz and 7000Hz, and the result is that they seem a bit recessed in the mids. The EL34 is a tube with strong mids and a bit less bottom end than the 6L6 and KT types, and the result in this amp is pretty much perfect for me with the Grado ‘phones.
So with a little tweaking and tube rolling, I really couldn’t be happier and my plan is to just listen and enjoy now (well apart from a bit more tube rolling). The Elekit sounds absolutely superb now, and every question I’ve asked along the way has been answered almost immediately by Victor and/or designer Mr Fajita.
It was a fun and rewarding build, but if you’re using Grado’s I highly recommend you go with EL34s unless you’re a dedicated basshead.
Sep 7, 2014 at 5:00 PM Post #28 of 1,441
Hi Greg,
Thanks for sharing your experiences with lower ohm headphones, such as the Grados, when paired with the TU-8200.
My sediments exactly; the EL34 is a great sounding natural, but neutral, tube with great air/soundstage and mid-range detail.  If you think you may benefit from a little more sparkle on the top with even more of a slight decrease in bass presence, the Tesla EL34 "Blue Glass" NOS variant may be worth a try.  To me they do everything the clear glass Telsa EL34 "yellow" labels do right, but with just a bit more sparkle and a little less bass; very nice when I want just a bit more on the highs with certain genres.
The Telefunkins and Philips Metal Base EL34s are often regarded as the best in this type, however they can demand quite high prices (I haven't heard either as of yet).  I've found the Mullards, different versions/getters, but all manufactured at the Blackburn factory, to be very nice overall, with great speed/slam/dynamics, but with a bit more bass presence and impact than other variants of the EL34 type.  Another great option could be the SED Winged "C" EL34, which are more plentiful and generally a bit cheaper (shop around), but with good all around performance.  NOS EL34s can be a little harder to find and bit more expensive because there are fewer out in the marketplace; plus, many boutique guitar amplifiers take these tubes as well, so you have to compete a little with others.
As of today, I've tried ~250 different tubes, and I would say ~120 different variants/brands, in this amplifier and I've found that the tweak-ability of the sound signature is almost endless.  I may put together a thread about my tube rolling experiences and impressions once I get some more time and get my collection more organized.
The great thing about this amplifier is the adjust-ability/tweak-ability.  Now that it appears that this amplifier does match very well to lower ohm headphones, in addition to higher ohm, and that the automatic bias feature makes the process of changing out different types of tubes so easy, I'm sure you'd be hard-pressed to find a headphone that doesn't, at least decently, match easily to this amplifier.  In my opinion, this is the ultimate test in good design and also a true testament to the talent of Mr. Fujita of Elekit.
I'm sure you'll be enjoying this amplifier for years to come!
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EDIT:  I think you also bring up a good point that I'm not sure if I went into much detail about in the review; while rolling signal tubes can give a nice slight variation to the sound/texture, they are more like an RCA cable swap, while a big change similar to the swapping of quality power cables, the power tubes give much more of an impact to the overall sound signature, bigger and more impact.  I believe this is mostly due, in part, to the fact that you are really only using 12au7s and slight equivalents that most of time are based on it.  Now, there are some variants that make significant changes, 7316s and such, but they can be hard to find and usually from one or two manufactures.  The power tube variants, on the other-hand, are much more unique among both types and manufactures.  I wish I knew more about how the automatic bias feature works, but I do believe most of the variation in bias it is handling is from the different power tube types being swapped, who are close but not exactly in spec of each other as far as the bias; could be why it more impact?  So, I've also found that the impact of rolling the power tubes makes much more (most of the time) difference than the signal tubes in the TU-8200.  Thanks again for sharing and keep us up to date on any other findings!
Sep 8, 2014 at 5:19 AM Post #29 of 1,441
Wow, that's a serious tube rolling effort Effusion. You must have just about worn the sockets out !
Thanks for the EL34 suggestions.
The ones I tried were the Mullard re-issues - because they were cheap and available, but once I realised this was the tube family I liked I bought a pair of Telefunkens off eBay (haven't arrived yet).
It came down to Teles or real (NOS) Mullards, so I'm hoping I made the right choice.
I'd love to try the metal base Philips, but the prices are crazy. Has anyone tried the Psvane replica - EL34PH ?
Have you settled on a favourite 12AU7 ?
I hope you get time to do that tube-rolling thread :)
Sep 8, 2014 at 12:25 PM Post #30 of 1,441
Just curious if any of you who has completed this kit experience any microphonics when inserting headphone into the jack or tapping/touching the chassis.  Mine does it.  Each time I touch the volume or anywhere on the chassis, I experience microphonics.  In short of removing the enclosure, I looked at the tube sockets to see whether it was making contact with the chassis but doesn't seem like it.
So far, audio bliss with all my headphones - LCD2.2, HD800, HE-6, with the exception of Fostex-TH900.  The best of the bunch with vocal music is the LCD 2.2 to my ears which for the first time I am experiencing a huge holographic image and a very rich and clear mids much more so than on my other diy - SOHA2.  It is a completely different level of sound.  What's really surprising is this TU8200 at UltraLinear can drive the HE-6 via 10 ohm resistors paralleled at the speaker outputs to a ear shattering level at 12 o'clock!
Will be trying the suggestions on tubes but like to spend more time with the stock tubes for the time being.

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