[Dimu]

  After talking with Victor and exchanging a few pictures, he has them orientated opposite of what you suggested...

 
I am pretty sure Victor is in the same hemisphere as I am, so induced currents would have to drain in the same direction- towards lower impedance relative to ground.

 

[JK-47]

Ok, fair enough. I'll by an oscilloscope and figure it out my self.

Hers is a good reference regarding inner and outer capacitor foils.
http://jimmyauw.com/2010/04/24/observing-inner-and-outer-foil-of-some-popular-capacitors/

By the way the Mundorfs do have a shorter lead indicating the outer foil. I was certain they were the same length. Anyways it has been a learning experience. Too bad you don't care to share too much @Dimu

http://www.mundorf.com/en/?category=hifi&menu=caps_audio&content=mcap_supreme_evo_silvergold

 

[MisterPC]

   
Not sure what kind of details are you looking for? I use LS50 for near field listening on my desk. Cossor 807 in UL mode power it more than adequately, sounds gets to unhealthy levels before audible distortion creeps in. I feed it with Gungnir Multibit DAC and the whole system is very sensitive to signal quality. For example I used it for a few days without Regen and the sound was noticeably grainy. But then again my TU-8200 and TU-8500 were built with the best components from the ground up. The only expense spared is that I used very few naked Vishay resistors. Pretty much all resistors are Amtrans, as many of them as I could get are AMRG. Bypass caps have significantly lower ESR than the best upgrades offered by Victor. Mundorf caps throughout including where they don't really fit physically. Upgraded power caps. TDK pots. Silver lead solder from WBT. The only thing that I still would like to upgrade further is output transformers. And of course tube choices are important. I still did not get to upgrading my power transformer so my amp keeps running Cossor 807s driven by E80CC. This is the best combination that I found that is compatible with the stock power transformer. TU-8500 is running a pair of Mullard 12AT7. All original tubes.

Thanks for the reply! What's your opinion about using the combination in a 15x18' room though with a lot of resonance? High wood ceiling, wood floor, drywall. I have a small upright piano and the sound is enormous in the room. A pianist listening from outside street remarked that it sounds like a grand piano. So, although the room's size seems to be of a concern, its  sound handling is quite efficient. In using the LS50's with the TU-8200DX, if I want to turn it up sometimes for early Elvis Costello, say, am I going to be disappointed? 
 
For reference, in my office, I have JBL LRS 305 monitors on my desk with volume controlled by an SMSL SD793-II and for me, this would actually be plenty of sound for the larger room; actually it's a bit more than I need for this sizable office. Based on your description above and mine here, you can see I have very little knowledge. Your input on this would be appreciated. I bought the LS50 speakers when they were on sale. Haven't used them yet and won't even get my hands on them for a bit; unfortunately, I won't be able to sample amps.

 

[Dimu]

  Thanks for the reply! What's your opinion about using the combination in a 15x18' room though with a lot of resonance? High wood ceiling, wood floor, drywall. I have a small upright piano and the sound is enormous in the room. A pianist listening from outside street remarked that it sounds like a grand piano. So, although the room's size seems to be of a concern, its  sound handling is quite efficient. In using the LS50's with the TU-8200DX, if I want to turn it up sometimes for early Elvis Costello, say, am I going to be disappointed? 
 
For reference, in my office, I have JBL LRS 305 monitors on my desk with volume controlled by an SMSL SD793-II and for me, this would actually be plenty of sound for the larger room; actually it's a bit more than I need for this sizable office. Based on your description above and mine here, you can see I have very little knowledge. Your input on this would be appreciated. I bought the LS50 speakers when they were on sale. Haven't used them yet and won't even get my hands on them for a bit; unfortunately, I won't be able to sample amps.

 
In addition to room, speakers, amp, signal source, etc, there is one more hugely important component that will affect the answer to the "are you going to be disappointed" question- and that is your brain. In fact it is two "brains"- your actual brain in terms of how you process signals from your ears and your "mind" brain in terms of your expectations. So I don't think anybody but you can tell you whether you will be disappointed.
 
Since you already have LS50 ordered look at it this way- TU-8200 drives LS50 to unhealthy levels before it starts clipping. Unhealthy means that if you sit 3-4 feet away from the speakers you get over 90 dB of sound pressure delivered to your ears. So I would say go for TU-8200 if you already got LS50. If you want more sound then you need bigger amp but I think you also need bigger speakers too, like something floor standing with multiple cones. So either get TU-8200 or get rid of LS50. Does that help?
 
P.S. when you get TU-8200 you can try running LS50 with 4Ohm setting at the back of TU-8200. I did it both ways and there is no harm, so you can choose which one you like sounding better. Keep the amp in UL mode though for what you are trying to do.
 
 

 

[Dimu]

Re-tested my tubes that I've been using in my TU8200. E80CC after over half a year of use show remarkable consistency- all parameters tested the same across all four triodes. Cossor 807 are showing a bit better parameters than 3 months ago but still noticeably weaker than 6 months ago. Not sure how to explain that- first it dropped after three months and then recovered a bit after three more months. Those tube started unusually strong though, so they are still testing much stronger than other Cossors that I have.
 
Summary is that after half a year of use both E80CC and 807 are very solid and give me an impression that they can last for many years in TU8200.

 

[Dimu]

Big ass transformer installed, sort of. Need to do more machining to close the case. I may be biased, but I have an impression that sound became deeper with the same tubes just by swapping out power transformer. It is possible as the core is much bigger on this sucker. It sounds so awesome that I don't really have any desire to try higher power tubes which is why I got that transformer in the first place...
 

 

[Dimu]

GEC TT21. Really nice especially if you like deep bass but I think big transformer made much more difference to Cossor 807 than stepping up to TT21.
 

 

[Dimu]

Telefunken made in Berlin. Not sure how to describe but these sound different, like they have very different frequency response. Higher frequencies are much more prominent it seems. Very nice but different. Will have to stick this into a spectrum analyzer one day to figure out what the difference is.
 

 

[Dimu]

GEC KT66. Simply awesome but I would need to spend a lot more time listening to figure out whether I prefer this GEC, the other GEC or Cossor.
 

 

[Dimu]

GE 6550. After listening to GECs, Cossor and Telefunken I am not impressed.
 

 

[Dimu]

I think TT21 is my new favorite. It has what Cossor 807 has, but more of it.
There is another problem however- I am afraid of closing the amp because both power transformer and the board run noticeably hotter than with smaller tubes. Especially the board is hotter, all the way to 63C where it says "danger high voltage".

 

[JK-47]

How about a pic how you have the capcitors mounted now that you have the amp apart? For the benefit of the entire TU-8200 community.

 

[Effusion]

 
 
This is the little brother of TU-8200
It has the same features of TU-8200 with  6AQ5 (6V6) X 2 + 12Ax7 X1

 
Looks great and I like the form factor; small enough to fit just about anywhere, yet able to drive near-field single drivers as well.  I'd be curious as to how it compares to the 8200!  Thanks for sharing Victor, I will be keeping my eye on it.
 
Dimu, thanks for all the pictures and impressions!  One of these days I'll have to do similar mods to run some of these.  I agree about the KT-66, I've found them to be quite nice, preferring my GEC Smoked Glass the most; my buddy agreed as well.  I also really enjoy the 807s.  Some of my favorites have been the Hytron Smoked Glass, the JAN types such as Sylvania/Westinghouse/GE, and a few of the European manufacture such as Siemens/Mullard.
 
I actually just picked up a pair of earlier AT-25s, round plates, saucer getters, and ceramic bases; very nice indeed and great sound all around!  Below are a few pictures (although taken in low light)...
 



 
 
Keep 'em coming and I'll try to snap a few more photos as well as add some impressions soon.
 

 

 

[Dimu]

Those are Cossors, probably the best match for this amp in its stock form. Based on my measurements if you pick up a good pair of Cossors they will last you a long time.
 
I've been comparing Cossors to TT21 without top cover and it seems like the amp is not designed to run higher power tubes despite manual saying KT88 and 6650 are ok. Things heat up noticeably more, including the core of the power transformer. The hot spots are the two power mosfets driving output tubes. I think I'll take my amp further apart to see if I can do something about those two mosfets- maybe even move them off the board to give them better thermals. The mosfet for the left tube is actually worse off than the right one because it is tucked into the board and airflow is more restricted there. I can't imagine what temperatures will be inside if I close the case. Mosfets might be able to take it for some time, but it won't be good for the rest of the circuitry including caps. Elekit did too good a job packing this thing into a small case. If they made it more loose it would have been better for upgradability and passive cooling. Another alternative would have been a case with aluminum fins but the kit would cost much more if they went that way.
 
 

 

[Hifi Boy]

@Dimu
 
KT66, my love, without a shadow of a doubt.
Beautiful sound at least compared to the stock ones you get with TU-8200.
Currently I have 75 hours on my Mundorf capacitors and 24 hours on the new Kimber Axios cable I got last week.
 
I can highly recommend the cable and can vouch that the cables certainly do make a difference.
Not just in some areas but across the board improvements.
 
Take for example Anne Bisson - September in Montreal.
 
The beginning of the song, and the first several solo piano keystrokes are incredibly smooth, soft and so "round".
We could say that the entire performance is exceedingly pleasing to listen to, like a veil has been lifted.
The sound is clearer and even the soundstage gets wider.