[Robert Padgett]

The Russian audiophiles in the forums are divided: one part suggests all Soviet tubes are crap compared to better European and US tubes; those who like tubes made in the USSR seem to agree that this MELZ tube is the best among them.

In the same forums, I came across an idea using only half of 6SN7 type double triod as a single triod, thus having a twin setup as if they were analogues of 6J5. Well, I saw that xuling audio had an adapter for 6SN7 for place of 6J5. What if I buy two of those (surely they just disable one triod in 6SN7?), and use two MELZ 6H8C through those adapters in a split adapter for two 6J5? Nah, it goes too far on a poor Vali 2. Maybe I should find a HP amp that's using two 6SN7, and stick the MELZ pair in it for a better soundstage?

While I am just a novice in tubes, it would seem that using two 6SN7 in an adapter, then into a 6SN7 to 6922 is "going around the barn to get to the otherside"...

Now a Valhalla 2 uses two 6922-type tubes and with a pairing of socketsavers(2) and a 6SN7 to 6922 adapter, those Melz would shine. I have a pair of 1951 ribbed plate Fotons that sound mighty good in the VH2.

In my opinion, the Vali 2 and a dual 6j5 adapter gets the best from the single triodes, which you have discovered. I was warned early on by both @Ripper2860 and @Paladin79 to never "double adapter" (the exception being direct wired socket-savers, and a Loctol to Octal adapters which are also a pass-through of pin-outs).

Congratulations on finding a source within Russia for the rare 1578 tubes at a very reasonable price!

 

[Paladin79]

Here is a way of lighting a dud tube without the use of LED's. You simply hook up the filaments to a quality power supply then over drive it a bit till you get the required glow. Do not try this at home kids.

 

[Old Deaf Donkey]

I have another query. I have bought a pair of Zaerix branded 6J5GT, which are supposedly made by AEG-Telefunken in 1973. So it says on the box



The tube is rebranded by Zaerix, a British company known for purchasing tubes in the Soviet bloc, and a bit from Mullard and GE. Apart of the Zaerix logo, it also carries another small sign:

apologies for bad quality, it is really tiny.

Now the tube construction (left or top) looks exactly like 6S2S made by Soyuz (right or bottom).



except that "Telefunken" tubes have very thin hairlike something spiralling on the inner surface of the glass, almost invisible - initially, when I noticed the first one, I thought it was a crack, but no: they are regular, symmetric, 4 in each tube.

No other reference on the Internet to AEG Telefunken made 6J5 or CV1934 - except those Zaerix branded, in similar boxes.

Russian made tubes in fake Telefunken boxes? Then, what about those hairlike things? EDIT: they are fine scratches on the glass produced by 4 pointed something holding the tube symmetrically on 4 sides and pulling the tube glass envelope through tem in a turning motion 90 degrees.

 

[Paladin79]

Interesting, you are building up quite the collection.

 

[Old Deaf Donkey]

Interesting, you are building up quite the collection.

Damn it! Had to order adjustable-cell storage boxes in China. Curious mind, stupid bitch. Telefunken has quite a reputation, I hoped it would sound special. Now I have not yet had time to evaluate. These MELZ tubes along with some 6J5 pairs coming close second seems to be it. OK, I bought one more pair in Russia, the Russians swear those triods are better than best of the 6S2S. We'll see.

 

[Paladin79]

I notice a bit more separation with single triodes but for overall listening pleasure nothing beats the Melz imho.

 

[Old Deaf Donkey]

I notice a bit more separation with single triodes but for overall listening pleasure nothing beats the Melz imho.

Exactly (although I need more time with MELZ vs. twin Soyuz 1955). Hence the idea of using two MELZ tubes as single triods!

 

[Old Deaf Donkey]

Apart of the Zaerix logo, it also carries another small sign:

apologies for bad quality, it is really tiny.

Managed to clarify this. It is a West German military acceptance sign, an eagle with BWB inside meaning "Bundesamt für Wehrtechnik und Beschaffung" - Federal Office of Defense Technology and Procurement. Supposedly, they were checking old Telefunken stock from 1950ties, selecting the best and repacking them, so 03 1973 is the date of certification and repacking, not production.

EDIT: presence of this sign does not guarantee that these are genuine AEG Telefunken produced tubes. It may as well be fake. Another possible explanation is that BWB is known for having certified some tubes produced abroad, and in principle could have measured and certified tubes produced in the USSR for West German military use (a little far-fetched guess for the Cold War times?)

 

[Paladin79]

This is mainly for Mr. Cowen but anyone can certainly join in. I was buying some dud tubes for some headphone stands I am building and a gentleman sent me a working RCA 6AS7G, CRC JAN clear top, three mica tube. He also threw in a Frankie 7N7 because I asked him if he ever saw those. It tests strong and works as well. I paid about $10 total for said tubes and luckily there are a couple duds in the batch or I would still be looking for tubes for my project lol. I turned around and bought ten lbs of tubes from him and explained that if he had any black or grey glass RCA 6sn7's tubes I would love them cause they cut down on the glare after I mounted an LED in the base. Whatever I end up with, I should be money ahead considering the first batch.

 

[bcowen]

Here's 2 genuine Frankies (left and right) with an imposter in the middle. For 10 bucks the one on the right measures well enough to be worth it.

https://www.ebay.com/itm/3-7N7-Tube...728419?hash=item340943a8a3:g:n8sAAOSwWm1cwOcz

 

[Paladin79]

I own more than enough for my usage right now. The middle one looks a bit shorter and the top appears to be rounded. The one I received says Philco pretty plainly and matches others I have that Ripper confirmed. I also just met a couple more Russian sellers so I would much rather pursue the Melz. Bottom mica may be a factor on the one as well, I just saw the other pics.

 

[Old Deaf Donkey]

The tubes you are discussing such as 7N7 - I cannot figure out an adapter for Vali 2... I was looking at split options and found an adapter for 2 EC8010, but they are $70 for a pair. Anyone tried them in Vali 2? EDIT: I cannot be helped. Found two Siemens EC8010 in Quebec US$36 for two + shipping and bought them. And the adapter from Xuling Audio. You'll hear from me when they arrive.

 

[Paladin79]

I am not sure there is a direct adapter. I use a 6sn7 to 6922 adapter. A 7n7 is a loctal (loktal) socket and you just need a loctal to octal adapter to plug into the 6sn7 adapter. You are not really using two adapters when you do this, loctal to octal adapts pin type. I am not familiar with the EC8010.


https://www.ebay.com/itm/1pc-Loctal...546362?hash=item2ee988b5ba:g:FpEAAOSwk1JWcoEl

The 7n7 is a direct replacement for the 6sn7, with different pins. Loctal or Lock In is pretty old technology and I want to say was used from the 30's to the 50's as best I can recall.

Bill is a proponent of specific tall body 7n7 that he calls Frankentubes and I bought several just to check them out. They are good sounding tubes that are hard to find NOS but occasionally you find them, I bought a couple out of France. I had plans of making my own loctal to octal adapters but unfortunately the sockets I received from China were not very good so I am scrapping the project till I find better quality sockets. Some of the 7n7's in my possession are pretty old and some care needs to be taken with the pins to insure they are straight and clean.

The top left photo shows what I would consider to be the sought after 7n7 with adapter, in the middle are the single triode versions, 7A4, VT-192 (miliitary version), and lastly on the right a hard to find version that to me, sounds every bit as good as the first version but lacks a couple characteristics that others seek. Appropriate adapters are shown. A 7A4 is the loctal version of a 6j5 and requires dual 7a4 to 6sn7 loctal to octal adapter.

Given a choice I prefer the dual single triode VT 192's in the Vali 2 because of the channel separation and overall great sound.

https://www.ebay.com/itm/1pc-Gold-p...155816?hash=item2ee7206628:g:ZYMAAOSwZupcTRBV

 

[bcowen]

I am not sure there is a direct adapter. I use a 6sn7 to 6922 adapter. A 7n7 is a loctal (loktal) socket and you just need a loctal to octal adapter to plug into the 6sn7 adapter. You are not really using two adapters when you do this, loctal to octal adapts pin type. I am not familiar with the EC8010.


https://www.ebay.com/itm/1pc-Loctal...546362?hash=item2ee988b5ba:g:FpEAAOSwk1JWcoEl

The 7n7 is a direct replacement for the 6sn7, with different pins. Loctal or Lock In is pretty old technology and I want to say was used from the 30's to the 50's as best I can recall.

Bill is a proponent of specific tall body 7n7 that he calls Frankentubes and I bought several just to check them out. They are good sounding tubes that are hard to find NOS but occasionally you find them, I bought a couple out of France. I had plans of making my own loctal to octal adapters but unfortunately the sockets I received from China were not very good so I am scrapping the project till I find better quality sockets. Some of the 7n7's in my possession are pretty old and some care needs to be taken with the pins to insure they are straight and clean.

The top left photo shows what I would consider to be the sought after 7n7 with adapter, in the middle are the single triode versions, 7A4, VT-192 (miliitary version), and lastly on the right a hard to find version that to me, sounds every bit as good as the first version but lacks a couple characteristics that others seek. Appropriate adapters are shown. A 7A4 is the loctal version of a 6j5 and requires dual 7a4 to 6sn7 loctal to octal adapter.

Given a choice I prefer the dual single triode VT 192's in the Vali 2 because of the channel separation and overall great sound.

https://www.ebay.com/itm/1pc-Gold-p...155816?hash=item2ee7206628:g:ZYMAAOSwZupcTRBV

The one on the left is a true Frankentube as you noted. The one on the right is an imposter. Not saying in any way that it doesn't (or can't) sound very good, just that it's not a true Frankie. The ones in the middle are HalfenFrankMutants. Round bottom micas. Possibly a HalfenFrank, possibly a HalfenMutantFrank. Haven't tried those yet, so can't pass along any (personal) sound impressions just yet.

 

[Paladin79]

I got the one on the right pretty cheap, but doubt I could pick it out in a blind listening compared to the other frankentubes. The one given to me is the real deal, the person I got this from is a little tricky to figure out, maybe just a hobbyist who just wants to unload all tubes he gets and not have to mess with them too much. I went back and bought most anything he was selling as duds for my headphone stand projects. I need small octal duds as well as large ones and it will be fun to see how many are really duds lol.

Oh yeah, I have a line on a group of Melz 1578's that are the real deal, hopefully I do not have to dip into my savings too much to grab those.

The 1579 is the 6sL7 version, it would be great if I could find something comparable to the sought after 1578 in a similar style tube but so far I have not seen it, time to investigate.