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Re: pre NS Mullards?

9/24/2004 10:07 AM
PAULH Re: pre NS Mullards?
They are undoubtedly Svetlana's made at the Moscow Sovtek factory. I've had mixed luck with these and choose to use the real winged "C" EL34's. The fact that these tubes say Mullards doesn't make them Mullards.
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9/24/2004 11:28 AM
bob p
Paul, it looks like they've put lipstick on the pig and they're getting ready to sell her.
9/24/2004 11:12 PM
The tube pictured appears to be the "Sovtek/Svetlana".  
New Sensor owns the Svetlana name in the USA so they have the Sovtek factory in Moscow making Svet type tubes. They have brown bases, slightly thicker glass, slightly different element constuction and early failure rates due to screen alignment from what I've seen. I haven't used them in a while for this reason. Who knows? they might have fixed the problem and stamped Mullard on 'em.  
I do like the 6CA7EH's in certin amps and the Sovtek/Electroharm EL34's do sound pretty good in my Dynakit ST 70's so it's not all bad. The consistencey of the Sovtek/Svet's is what bugged me.  
Sometimes the ran great, sometimes, POOF!
9/24/2004 11:29 AM

The EH 6CA7's I got were definitely not the Ei type. The Ei's have thicker glass, a wafer base, and a nipple at the top, so they look kind of like oversized 12AX7's. The EH's were made in Russia, the Ei in Yugoslavia.  
Neither of these were actually a good substitute in a 50W JMP which has original screen stoppers. The screens glow far too much under overdrive conditions with numerous extra-bright spots on the EH.  
The EH EL34's seem to have tougher screens or sometimes better geometric alignment, if carefully selected you might be able to get a pair where they draw similar currents at idle plus also have lower-than-typical EH screen overheating, with relatively matched glowing at maximum volume. You really need to pick the very top performing of these EL34's and then you might be able to compare reliability with how the amp was when new.  
The Russian tube labeled *Mullard* in the picture sure looks extremely close to the EH EL34 which was claimed to be the best copy of a Mullard when they were released anyway. The only obvious difference is the brown base and the micas now have reduced circular diameter with the additional support clips contacting the glass rather than the *star-shaped* glass-contacting micas without clips on the EH.  
A real desirable NOS Mullard like a xf1 does have a similar-shaped plate but the halves are welded rather than crimped, and the vents are different, plus there are support rods that have been incorporated into the welds on the sides of the plate. This New Sensor Mullard does not have these support rods and the plates are crimped instead of welded, just like the EH.  
One angle I do think may have some potential to arise is the possibility that the box can be more valuable than the tube when it comes to an old British-made Mullard. Someone with used worn out tubes that happen to look clean & perfect would find it much easier to pass them off as NOS if they could get fresh pristine boxes a little easier in some way. Apparently New Sensor would now be entitled to reissue any of the traditional Mullard boxes in as exact a detail as they might want to, not just for EL34's but 12AX7's and everything else. Might be a little easier to make a box which is indistinguishable from the original than it is the tube . . .  
9/24/2004 5:18 PM
Ian Anderson

Lay off them, I think those EL34s look cute with the little Mullard logo on them ;) :D They look to be winged-C Svetlana factory tubes so the quality is at least good (still not Mullards though)  
The EH 6CA7s I thought sounded great for the ten minutes they lasted in my plexi. Maybe under lighter load conditions they'd do better (i.e. plate voltage around 400vdc)  
Finally, I'm sure there's been an explanation here before, but why (with all the experience of tube manufacture out there) can't anyone recreate Mullard tubes?  
... Ian
9/24/2004 6:37 PM
Greg Simon
Someone could recreate Mullards, and Genelex, and all of the other better made NOS stuff. They would have to charge a bunch of money for them though because the time and labor cost to make each tube would go way up.  
9/25/2004 6:24 AM
Ian Anderson

So how did they do it back in the day and make them affordable?  
... Ian

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