Elekit TU-8200 DX Headphone/Speaker Amp Review

Discussion in 'Headphone Amps (full-size)' started by effusion, Jun 10, 2014.
  1. Hifi Boy
    Wow. Sounds too good to be true! :D

    BTW, Wall of Sound review is still not up, after more than a month now...
     
  2. vkung
    any time Noam is writing it now..
     
  3. lucidreamer
    Does anyone know if I can use 6085 tubes with my stock Elekit 8200 amplifier without any problems? I am currently sticking to my RTF 12AU7 pre-amp tubes and find them the best so far with TFN ribbed plates on the way to try. But I am thinking of purchasing the 6085 tubes to try in my amp because there are great reviews about those industrial versions of '12AU7' and they are supposed to be interchangeable with higher driver loads. Thanks.
     
  4. Hifi Boy
    Hi lucidreamer.

    I personally can't say, but I have googled the tubes you described and I do remember that someone here recently posted some pictures of his TU-8200 with these tall input tubes you mentioned. I'm using 12AU7 so I immediately noticed that the type is different because yours are much taller.

    I'm sure Victor will be able to give you a better answer.
    If not, you should try to contact the very helpful Tamura-san from Elekit.
     
  5. lucidreamer
    Thanks Hifi Boy. I ordered a pair of Philips E80CC tubes from the seller in Belgium and it may take a couple of weeks to arrive. I am also considering getting a pair of Tungsram E80CC which should provide a different sound signature compared to Dutch tubes.
    I am 99% positive that it will work just fine in this amplifier without making any modifications which are suggested by other forum members. I double-checked the schematics again and the stock rectifying bridge circuit consists of DB107 diodes which are rated at 1A of current, therefore, it should suffice to drive the E80CC heaters at 600mA. The worst-case scenario is that there will be not enough current to drive the power tubes and it may need a transformer upgrade which is unlikely, this amplifier has the reserve.
    I did an extensive online search on that subject and there are no cases of someone blowing up their amps by switching to E80CC tubes. Only a couple of people stated those tubes sounded very quiet in their setups, but each amplifier is different, some Chinese ones use small cheap parts that are on the edge and have no reserve.
     
  6. Hifi Boy
    Sounds good to me, please let us know your opinion once they arrive.

    The only thing I can add to this is that me personally, I've never noticed any difference while changing input tubes.
    Now, I'm not saying that there is no change, or that you won't notice anything I'm just telling you what my experience was.
     
  7. lucidreamer
    There is a significant variance between different preamp tubes in terms of their sound character, transparency and dynamics. I can hardly hear much difference when listening through speakers but with the headphones it is a different story.

    I just got a pair of nice GE 5 star 5814WA and those are so sweet.
     
  8. Effusion
    Harry_Y, welcome to the club!

    The TU-8200 is a great amp for desktop use and this is where I actually use mine. You are right about it being small enough, yet powerful enough, and with more than enough features to keep you satisfied. I do not know much about the new 8600 yet and have never heard it, however besides what you have already noted, since the 8600 uses 300B tubes, unless you are crazy about this tube type, which are quite amazing, it doesn't make much sense for desktop use, compared to full/main setup use. The 300B tubes can go for crazy amounts of money, with true WE NOS being almost impossible to find, at least at an 'okay' price. There are other options for the 300B out there for sure, but I've heard from those that love this tube type, that quality can vary, especially with some of the newer production. I've also heard that the 300B tubes can also get very hot, which may not be ideal for desktop use, depending on your situation. Now with that all said, the 300B tube is probably considered one of the best, if not the best, tube type for audio use in general and it has been highly praised for many years. I believe Elekit also has experience using this type in their other designs, so I'm sure the 8600, with nice 300B tubes, would beat the 8200 sonically. However, the question is, by how much and if it is worth it for you and in your system in the long run. Going off what you have stated, I think you made the right choice, plus in the future you can always try the 8600 if you want to, plus now knowing that you have given the 8200 a chance.

    As an additional note, some of the power tube types for the 8200 also get very hot. In my experience these are generally the KT-88, KT-66, and 6550 in particular. If you are concerned about heat build-up in the case, which I was, and also which can lead to additional component ware over time, you might want to consider a passive cooling system to help dissipate it. Several users here, including myself, have implemented solutions that can help with this. If you prefer to not make any holes in the case, which may let RFI/EMI in, one option is to use tube socket savers on the power tubes, in order to lift them off the hood of the case a bit, thus creating less heat transfer from the tube to the metal case and thus eventually inside the case. Just be aware that most socket savers are for tube testers and not for HiFi applications, so choose wisely and let me know if you want some recommendations.

    Let us know how everything goes and what questions you may have during your new journey with this amp.

    Lucidreamer, I agree with you that the input tubes do change/alter several characteristics of the sound, such as signature and tone, and can really bring out the best in the amp. However, I also have to say that I've generally found that the differences are slight in comparison to what can be done with the power tubes, similar to HiFi Boy's experience. However, we must remember that in stock mode, there are many more easily available and different types of power tubes that can be rolled than within the direct 12au7 input tube family. In my experience, going from a KT-88/66 to a 6L6GC and then to an EL-34, gives quite a bit of difference compared to different brands/designs within the input/signal tube 12au7 family. However, as I believe you are experiencing with the 5814WA tubes, switching out of the direct 12au7 tube family will yield much more noticeable differences, often times better as well, and there are several types that I recommend. In particular, the Brimar 13 series, the Amperex 7316 (my personal favorite), as well as the Tesla and Telefunken ECC802S, all in addition to the 5814s, have given me much better sound, to my ears, than most 12au7s. As far as the 5814 family goes, my personal favorites are the CBS black plate and Westinghouse types; I have tried GE black plates and found it to be a bit stiff and emotionless compared to others, however they were not the 5 star. In general and across many different types of NOS tube families, I've found that the militarized versions generally will give tighter, more dynamic sound, with better highs and tighter bass, if not just a bit less sweetness and air overall than non-military types. To me they generally sound more solid state, which can be a good or bad thing based on the rest of the system and your preferences.

    From my personal experience, the best advice I could give to anyone looking to do more rolling with this amp is to first zero in on which power tube types you prefer overall and then tweak the sound by trying various input tubes (from different families as well) with them. Also, a great resource is fellow owner and member Dimu, who has done extensive rolling in this amp, well outside the standard 6L6GC/12au7 family and with great reported results.

    Happy listening all! :darthsmile:
     
  9. Hifi Boy
    Hey @Effusion, haven't seen you in a while. :)
    Are you planning on getting the new TU-8600?

    @lucidreamer, its great that you can hear these differences, I can't.

    Let me just tell you what made most difference to me:

    Electroharmonix 6L6GC to Genalex KT66 - Big Difference
    Genalex KT66 to Genalex KT88 - Noticeable Difference
    Genalex KT88 to KR Audio KT88 - Somewhat Smoother Presentation, no artificial bass bloom, nothing more

    As for the input tubes, whether stock or Genalex 12AU7 or Psvane 12AU7, I did not notice anything.
    Maybe I could try stock VS Psvane again, but I doubt I would notice much.
     
  10. lucidreamer
    WP_20170905_18_15_33_Pro.jpg I just got a package from Belgium today with a pair of Philips SQ E80CC/6085 tubes that I bought from eBay last week at a reasonable price. This is indeed a different animal in this amplifier and this Heerlen-made tube from Holland sounds like the best 12au7 on steroids. The sound is very clean, dynamic and transparent yet still tube-like and not solid state but rich and pleasant. The first impression I immediately got was the sound became 'quicker' and not as laid-back or lazier as before with the GE 5-star ones, still the 5-star ones are best overall for me.
    6085 are really interesting tubes to compare against the 12au7 types. The volume is a bit louder too because they have a higher gain which is not a big deal. I have an impression that they are so revealing that perfectly-recorded tracks sound better with them but poor quality ones sound even worse. The instrument separation is noticeably better and the music has become slightly more 3-d.
    I am still a bit nervous to keep the amplifier running them for longer periods of time because they demand twice more current, however, after about an hour, the sound is still the same, no smoke or other malfunction symptoms detected from the amplifier which is a good start. I hope this amplifier will have the reserve to run them (fingers crossed).
    I have settled on the Mullard EL34 X2F for power tubes and those are taming the highs a little bit. With other power types, like KT88 or military grade ones it would probably result in a fatiguing experience at the end of the day. Even matched with the EL34s - it may be a bit overwhelming for some types of music to listen to for a longer time, I am afraid.
    Now waiting for a pair of Tungsram E80CCs to arrive from Ukraine to compare with Philips.
    [​IMG]
     
    Last edited: Sep 6, 2017
  11. Allegroz
    Is it safe to use e80cc + el34 witch stock transformer and stock part?.. or I must upgrade some part to use that tube..
     
  12. lucidreamer
    I am running E80CC with stock parts (actually a DX version with upgraded capacitors, resistors, etc.). So far it is ok but only time will tell. Like I mentioned earlier the stock DB107 diodes are rated at 1A and should be fine to drive these tubes. The power transformer is also pretty beefy and is 250va. An extra 2w of load should not do anything to it, there are tons of posts on this site where people run those tubes with smaller amps and did not blow them.
    But to be extra safe - you can upgrade the DB107 diodes to something like 2A and also upgrade the power transformer to a bigger one that can fit in the case which would be a challenge and a significant expense. I would not bother doing that if it were me.
     
  13. Dimu
    It is a very, very good amplifier. At least mine is, but I put the best components I could find into it from the very beginning. Resistors, caps, TDK pot, etc.

    Get a bigger rectifier for preamp heater supply so that you can run E80CC with smaller power tubes. Then get a pair of Dutch E80CC. Unfortunately this is where meaningful tube upgrades end because you can only mix E80CC with 6L6GC or 807 tubes using stock power transformer. Still, upgraded rectifier with E80CC and good 6L6GC or 807 is the best sound you can get out of stock transformer- much preferable than 12AU7 with any power tubes (I tried pretty much everything worth trying other than TungSol 6550). I would recommend Cossor 807, RCA 6L6GC black plate or GE 6L6GC. Sylvania is ok too. E80CC has twice the plate size of 12AU7 and consumes twice the heater current and that does make a difference.

    I've been listening to E80CC and Cossor 807 from 1950s before I swapped out power transformer to a bigger version. I could hear difference with the bigger transformer right away (I swapped transformer for more heater current, but I guess bigger core influenced signal power as well), but more importantly it allowed me to install power tubes with bigger heaters while retaining E80CC. After some experimenting I ended up using for months Telefunken EL12 spez made in 1960. Today I swapped 807 back in and it is clearly lacking, at least to my taste. Put GEC TT21 in there- better than 807 but still lacking compared to EL12 spez (TT21 is GEC KT88 with top anode for higher voltages). Then swapped in GE 6550- similar sound to TT21. Next came Mullard EL34 XF2- this was closest to EL12 spez sound of all the tubes I tried today. So I gave up an popped EL12 spez back in- feels like home again. Another bonus with EL12 spez is that amp runs very cool- huge difference relative to bigger tubes. Those Mundorf caps will sure be more comfortable than with bigger tubes that overheat the amp.
     
  14. Dimu
    If you do that you will overload preamp heater rectifier and you will overload the power transformer. Rectifier might give you unpleasantly smelling smoke at some point, but transformer overload consequences could be more interesting. The question is whether amp's 3A fuse will stop really bad things from happening after transformer coils fail due to extended over current operation.

    Upgrading rectifier is trivial and costs just couple or three dollars. Upgrading power transformer is a project. So you have two easy choices:
    - EL34 with 12AU7
    - 6L6GC with E80CC and upgraded rectifier

    I would go with the second option.
     
  15. Dimu
    Please don't confuse people with conclusions based on bad math- not when it comes to safety. E80CC is rated at 0.6A current. That is nominal rating, actual current draw can be higher than that. And you have 2 tubes. So you are definitely looking at more current than what those rectifiers are rated for. DB107 has maximum sustained current rating of 1A at 25C ambient temperature. Temperatures inside that amp go much much higher than that, especially if you use big power tubes. So you are over temperature and over current, both by unhealthy margins. How does that qualify as "should be fine"?

    What do you mean "pretty beefy and is 250va"? How is that going to compensate the fact that having 1.2A rectified plus 3A RMS current far exceeds the 6V secondary rating of 4A? Elekit recommendation is to allow for twice the current on transformer end relative to what rectified current is for the heaters. Also for your information, a properly designed transformer to accommodate those extra heater amps requires "beefier" core than the stock transformer.

    And where do you get 2W? Power leaving that transformer coil is much more than 2W over rated power if you use E80CC and EL34 together.

    When you say "extra safe" you are implying that if you don't do those things you are "reasonably safe". This is obviously wrong- bad conclusions based on bad math.
     

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