Originally Posted by hypnos1
Hi gibosi - and oskari - and anyone else interested, as things seem to have gone very quiet on the 6HM5 front (no wonder, with the exciting experiments going on courtesy of AFB once again!...).
Anyway, my "premium quality tubes for export" arrived today and my word, they are of VERY classy construction. Yugoslavia on them, with codes that ARE Philips, but NOT Mullard...
Actually : tZ1 (= tube type PCC 85 ) and G5A (G being Loewe Opta, post-1954, and Mullard/Fleetwood prior. As 5 must be '65, we are looking at Loewe therefore - no wonder the tubes look classy...they are quite some outfit, no? And no doubt VERY picky...
So, popped them in; gasped at the blinding flash from their bottoms that ensued; resisted the temptation to switch everything off; calmed down as they settled to a beautiful glow, and (thankfully) was rewarded with a sound that bodes very well indeed right from the off. These would appear to have the potential to knock the lovely RCA 6DT6As off their lovely perch...time will tell...
Originally Posted by Audiofanboy
Factory code "G", you sure? Maybe factory code:
EI, Nish factory, (ex-)Yugoslavia. The similarity with a "G" isn't that obvious here, but on the pics of real tubes I've seen and on my EI ECC88, the factory code circle is longer and more "circle-like", making it look like a 90° turned G to the untrained eye -or uninformed soul lol.
Factory code "G" would make little sense, whereas the EI factory is about the only Yugoslavian tube maker I know about.
Depending on the tube type, EI could have used Philips machinery (ECC88 for instance), Telefunken machinery (ECC83 for example) and maybe even some other production gear for all I know. These tubes, with their shape (top "nib") and codes, could have been made on ex-Philips gear. Or maybe not. If we compare it to a Mullard Blackburn or Philips Heerlen-made tube, we might be able to tell.
Many thanks for putting me on the right track - with stronger glasses, more light and an indication of what to look out for, NOW I see the inverted "G" is NOT a "G", but a very strange symbol similar to your diagram. Sincere apologies for misleading/confusing anyone with my mistake...
They are still, however, a very nicely-made tube and I look forward to hearing more opinions on them. As for myself, early impressions surprised me somewhat, as the sound was quite different to the RCA 6DT6As, and after 20+hrs I still can't decide whether I prefer them or not. I think it could well be down to the extra soundstage/'3D' effect plus more detail. But at the moment I am wondering if this is at the expense of a certain degree of focus and coherence...Vocals appear a bit further in the distance, and to get the same hard-hitting bass requires more volume, which is not so good for my ears! Everything is so wonderfully 'clean' and clear, however, that I pray further burn-in will resolve such matters...Or that I simply need to get used to the different sound!
Whatever, I do hope more of you get the chance to try out these tubes and post your findings.
BTW - setting is EF95, no strap (don't know if any other is possible/adviseable...)