Hi bbmiller and all you guys in this thread.
I just thought I'd hop over from the Little Dot Amps: Vacuum Tube Rolling Guide and see what's cookin' here... and would like to pass on a summary of what we have been up to in our quest to see how far the LDs can be pushed, without blowing them up, lol! Hopefully there might be something of interest/use to some of you who want to get the most out of your MKIV SE.
I personally am a fairly late-comer (1yr ago) to a bunch of really great, friendly, helpful enthusiasts who have spent a great deal of time, effort (and money!) experimenting with a range of LDs and who have made some pretty amazing discoveries over time regarding which tubes can be substituted - with or without modification - for stock. And my first bold statement is that ALL, and especially my IV SE, can give results
way above stock.
I will give more details below, but perhaps I can first whet your appetite with a few pics :
The drivers are Siemens C3gS's - which are plug 'n play with a C3g to 6AK5 adapter available on ebay ( mine are my own, made with pure silver wire, 'cos I
love silver!) and on EF95 setting.
These gave the first MASSIVE improvement - even over the Voskhods, and our later use of the 6DJ8 family (with mods). We found (one of) the best straight replacements was the tall-bottle 6HM5, which beat the Voskhods easily.
Other guys have also found great improvements using 6SN7s as drivers, but require more adaptation still.
The next almost equally huge improvement came from different POWER tubes...YES! - contrary to established belief. Further info below...
Please, please, please DO NOT waste your money on the 6N30P-DR (TD's characters are strictly more correct!). I spent £200 - yes pounds
- on a pair, and while they gave a
little more than the stock 6H30P, no way were they worth that sort of money. For MUCH less, you can achieve good results from (once again) the 6SN7 family. These too are plug 'n play, using a 6SN7 to 6CG7 adapter from ebay. For these, and the other drivers, you will need to remove all the brass bits to accommodate the adapters. And again, on EF95 setting.
In the above photos, first I had a Psvane CV181-TII (basically a 6SN7) in the left channel and a 7N7 (which needs a different adapter to the 6SN7) in the right. Yet again, going against previous findings, the mix gave amazing results - each filled the missing parts of the other, without any clash or imbalance.
But finally came a leap to equal that of the C3gS drivers...
6AS7G's AS POWERS!...unfortunately, this is not so easy to achieve - they require a 2.5A heater power supply, as opposed to the LD's native .9A. So, therefore, if you have never held a screwdriver, pliers, or soldering iron - or can't get a savvy friend to do the job for you - I'm afraid you probably will not be able to experience the humble MKIV/SE to a level that is totally beyond belief...and I'm not foolishly/ignorantly overstating the facts. I never dreamt my Senn HD 650s could sound as they are now doing.
If you are interested, and would like to know more, just have a look on the rolling thread mentioned previously. I can only hope this change would/could be possible for at least some of you. Or at the very least, give the easier-to-adapt 6SN7 (or 7N7) a try - I don't think you would be disappointed. Thankfully they are ALL good, and not too expensive... and if you are fairly flush, they will definitely sing MUCH better driven by the C3g (preferably the 'S' version, if possible).
ps. The 6AS7G/6080 tube draws a
lot of current, and an earlier concern was the strain on the cathode resistors. With help from TrollDragon, pointing out the ones to look for (after artsi's warning), I monitored the outside temp of same and although much higher than stock 29C, after 1 hour they slowly reached 56/57C and then just 59C after 4 hours' continuous play - which I believe is way below max operating value - so it looks like all should be OK. And I have put a good few more hours on my baby...she gets somewhat warmer than before but hey, those tubes get
HOT! And no nasty surprises as of yet. The only ones being more mind-blowing ones with each different test track I have been using for a long time now. I cannot overstate the level to which these power tubes have taken my LD.
Hi Chris J.
As mentioned above, until the 6AS7G especially, that
was the case...but no longer. The versatility of these LDs - especially the MKIV SE - is quite amazing. This has been demonstrated time and again by the guys on the rolling thread.
And all I can say is that if I had taken TD's advice to "stay away" from said thread, I would have missed this opportunity to achieve a level of sound reproduction I NEVER thought possible, without spending thousands of pounds, lol!
Well folks, I hope I haven't put you all in 'overload' mode, but at least given you "food for thought"...
Cheers, and happy rolling?!