Originally Posted by MIKELAP
Might need more than that!
Looks like I must have sold my soul to the Devil...'cos not only do the 6as7s work in the IV SE, but even with just 1 in the right channel and the Psvane in the left the result is downright mind-boggling! The difference already sounds very similar to what you hinted at coming from your Woo...further info below...I still cannot believe that what I jokingly (with forlorn hope) tossed in the air re using them in our LDs has actually come into being - and beyond my wildest expectations. The Woo will have to wait a good while now lol!
Originally Posted by TrollDragon
This is my MK IV board, the SE should be the same except for upgraded capacitors and jacks.
The two resistors circled in red are the 150Ω cathode resistors that Artsi spoke of, these resistors are 1 Watt. The two White Square resistors on the right edge of the board are 5 Watt sized just for reference.
If running the 6AS7's as power tubes with the 1W resistors draws too much current, the most that would likely happen is you would just burn out those two resistors. The heat / flame generated when these resistors burn would cause much stress to the two caps on either side. If it doesn't cause any trouble to the circuit board underneath as well.
This is a 1/4 Watt resistor with too much power through it, the bigger the wattage the better the burn. :)
So What Do?
New resistors come with long legs, you could put 5 Watt or 10 Watt resistors in place of these 1 Watt's for a few dollars each. Bend the legs and the resistor would have to be mounted in the air a little as it would not fit in the other resistors space.
Then the resistors would not burn out, the transformer would...
I have to thank you once more TD for showing me the target resistors...despite a nasty crick in my neck after hours of peering inside the unit with temp probe in hand, fortunately it looks like once again the LD (MKIV SE at least) heaps surprise upon surprise. With the outside temp of said target being 56/57C after 1 hour and just 59C after 4 hours' continuous play, I think all should be OK, yes? - WELL below max operating temp, I believe...so hopefully no nasty surprises in store
I can only hope other models are similarly forgiving...
And so now, guys, an update on this most unexpected development :
After a good many hours of my favourite test tracks, and much to my disbelief, my initial comments only just touched the surface.
The dynamic sound and extra upper bass and lower mids did not come at the expense of anything else whatsoever...on the contrary, there's even more detail across the entire spectrum. It would appear that no matter what part of the system is changed/upgraded, the C3gs maintain a perfect balance in all respects, and just keep on delivering more and more. Coupled with the 6AS7G (and still only in the right channel, with the Psvane in the left), at first it's almost as though there's too much detail, but when you hear it with pinpoint precision and placement, the end result is truly mind-blowing. This gives true holographic imaging and soundstage. Again, this doesn't come with a heavy price-tag...vocals (especially female) stay nicely, and intimately placed - not lost somewhere in the 3D stage!
There is increased tonal range, both vocally and instrumentally, and a particular quality of reproduction that I have never properly noticed before, exemplified by, of all means, a tambourine in an old ELO track - ie you could hear the shake running around its rim like a musical ferris wheel (moving VERY fast, mind you!)...amazing...
Bass had even more depth - not heavy-metal heavy - but with exquisite detail. And as for treble...sweet, delicate (especially with percussion), detailed and with delicious decay hardly does it justice.
Anyway, that's just a taster of what the 6AS7G has delivered...had better get back to the "roller widow" before I'm in the dog-house!.
Will update again when I've finished the adapter for magical tube #2...
Cheers for now.
In case you missed the pic first time round :
Edited by hypnos1 - 5/11/14 at 12:42pm