GeorgeP

I suspect the xf2s aren't going to help you. What headphones are you using? The other possibility is that electrostats are not what you are looking for.

Just curious, are rounding to the nearest volt or are these your actual measurements? Also, is the no constant variation?

I seem to remember reading there being an impedance issue with the JT. You might want to double check that it will work from that perspective.

Bdent is obviously the safest, but there are other good sources for 3675 ($1-2) and 3381 ($1-2). Still more than the newer stuff from mouser, but not a lot more when you consider the overall cost of the t2.

Marc, is your board the original one that Kevin organized or the group buy that Tran did (not the more recent failed group buy) (or your own board but made from the original version)? From what I could tell, there were a few fixes that were incorporated in the Tran group buy that made it more stable out of the gate. Haven't tried Amperex 6dj8 but do recall someone saying it sent some of their transistors to an early grave (I recall they were bugle boys) - I have only used JAN Philips 6dj8 from the 80s and some german-made siemens from the 50s or 60s, all without issue.

Same spacing as the original board or the slightly smaller one?

Really interested as well - thinking about a second one. Love the quote too by the way.

nope.

Yeah, 70 is a few more than I have as spares. Were you going to do it fully SS at the board level, or use SS socket plug-ins like JoeMat did so you can opt for either tubes or SS?

How many do you need? I may have a few I can spare if you can't wait for stock.

Maybe there is some difference between the el60 (yours) and the el61 (the ones listed) along the lines of what Marc is pointing out.

the SumR traffos in my two KGSSHVs (when I had them) ran just slightly warmer than ambient. My SumR traffos in my T2 are at about 25-30C above ambient, but they have a 1 inch clearance from the top of the case (whereas the spec calls for something in the neighbourhood of 4-5 inches - going by memory).

Sounds about right, with 1600 being for a fairly used pair, perhaps without the case. And this pair apparently came with an extension cable (probably the older one) which is propably worth $50.

Really cool build! But how are the transistors connected to the heatsinks - did you use a bracket?

yes, switched them... went to bed at 1am and was up at 5:30am so a bit baked at the moment.

Does it have to be zero, or pretty darned close to zero? My measurements are the same as in this earliler post with the batteries (re-measured a few months ago) sitting at around -200 and +544 on each side. Not sure how keen I am on earning extra credit though...

Any black-framed MK2 that are in the SZ2 range, or did that export colour change come about with the SZ3 iteration?

My experience with digikey has been that I receive the order the day after I place it - without upgrading shipping. No guarantees obviously...

right, of course (kick's self in the ass).

Where are you finding the pricing and such for the upgrade? I clearly suck at surfing the interweb...

Shouldn't make a difference except that you should ensure the feedback on 0.6 is set correctly. I believe 0.4 may have had an error or two that is/are easily corrected while building - but corrected in 0.5 - this should be set out somewhere in this thread.

Agreed.

Marc, are you on your original transformers or did you make a change after time for temp reasons? And did you end up going with SumR? I corresponded with Richard a while back about getting second set as a back-up and specifically addressed the temp rise issue - he suggested he could make some changes to the flux (going by memory, would have to dig up his email) to get the temps down - he seemed reluctant to change the size of the transformers for some reason (or could have just been my interpretation). Les, if you look around the first quarter or so of this thread, you will see some transformer design considerations (I believe made by Craig Sawyers). Those posts may (or may not) be useful. I believe Craig got his transformers locally (ie. England).

If need be, how does one get paid for providing you with the requested info?

Me too. Though my Sumr transformers have been reliable with about 1000 hrs on them (with one of the HV transformers developing a light buzz early on). Design temp rise is 33C for filament and 26.4C for HV - but that is with 16 inches of air clearance while the KG chassis has roughly one inch of clearance. If I recall, the surface temps were into the >50C range. Though wouldn't mind having a beefier set as a back-up. And vertical fins would add a lot more surface area than the horizontal fins (but don't look nearly as bad ass). What sort of temps are you getting with vertical fins?