The Reference 6SN7 Thread

Jun 1, 2023 at 12:44 AM Post #8,881 of 10,650
What a difference a few days make. First, I need to thank JTbbb for all his help and excellent tubes. With all the talk of ECC32s, I had to give them a try. Other than the blue balls that came with my Baltic 4, I run real 3-hole 52 Bad boys. They sound fantastic especially with all other tube upgrades.

I plugged in the Mullard... Meh. Nothing special. Not bad, just not better. I put some Brimmar CV-1988s in... Very close to the Sylvania. A little disappointed, I've heard such great things. Put some time on them, nothing. Make my mind up to move the mullars keep the Brimmar simply based on my preferences.

But I noticed some spots forming above the heating elements... Like flashing. Wasn't there before. Long story short, they had zero hours on them, not even burned in. Put more time on them.... Oh... They're special alright. They have that Signature Mullard bottom end, but calling them warm would be a disservice. I think the top end is better, certainly more refined. Stage and space are better. What a fantastic tube... That I nearly moved. 😳 And it's not my imagination, when I first plugged them in, they sounded good, but a clear step back. My bad boys are spares now. They are more mid forward, more in your face, in a good way. They really are very good top to bottom. Not going anywhere.

I put more time on the Brimmars... Those too had hardly no time on them. They developed spots too, but not to same extent. They did get better. I still consider them equal to the Sylvania. But where they shine is they are not in your face, but they are more accurate. They almost make the Sylvania sound colored. Very transparent top to bottom. Very easy to listen too. I just don't need all three. The last piece to my puzzle. Some one should enjoy them, they look fresh from the factory. PM me, they are available.

Then... A while back, I got a pair of 12BH7 Sylvania oval plates to try. Clear step back compared to my Mazda ladder plate 12AU7s. Love those Mazdas. Well those 12BH7s were up for sale, but not anymore. I put more time on those... Which I did before... A day or two... But I tried them for giggles, they were not bad. With more time, I think they equal my Mazdas for sure. I give the win to the 12BH7s by a hair. I think stage and space is better with the oval plates. So now my Mazdas are back to spares for my amp. And I think I picked up a bit of volume which is always good.

I just never assume NOS means not used. All my other tubes have never changed with any burn in. But they I would have made a big mistake. Even more real, more space, that incredible Mullard bottom end. So easy to listen to. So pleasing. Stopped comparing and lust listened to stuff for another hour. I'm officially done.
 
Jun 1, 2023 at 10:12 AM Post #8,884 of 10,650
What a difference a few days make. First, I need to thank JTbbb for all his help and excellent tubes. With all the talk of ECC32s, I had to give them a try. Other than the blue balls that came with my Baltic 4, I run real 3-hole 52 Bad boys. They sound fantastic especially with all other tube upgrades.

I plugged in the Mullard... Meh. Nothing special. Not bad, just not better. I put some Brimmar CV-1988s in... Very close to the Sylvania. A little disappointed, I've heard such great things. Put some time on them, nothing. Make my mind up to move the mullars keep the Brimmar simply based on my preferences.

But I noticed some spots forming above the heating elements... Like flashing. Wasn't there before. Long story short, they had zero hours on them, not even burned in. Put more time on them.... Oh... They're special alright. They have that Signature Mullard bottom end, but calling them warm would be a disservice. I think the top end is better, certainly more refined. Stage and space are better. What a fantastic tube... That I nearly moved. 😳 And it's not my imagination, when I first plugged them in, they sounded good, but a clear step back. My bad boys are spares now. They are more mid forward, more in your face, in a good way. They really are very good top to bottom. Not going anywhere.

I put more time on the Brimmars... Those too had hardly no time on them. They developed spots too, but not to same extent. They did get better. I still consider them equal to the Sylvania. But where they shine is they are not in your face, but they are more accurate. They almost make the Sylvania sound colored. Very transparent top to bottom. Very easy to listen too. I just don't need all three. The last piece to my puzzle. Some one should enjoy them, they look fresh from the factory. PM me, they are available.

Then... A while back, I got a pair of 12BH7 Sylvania oval plates to try. Clear step back compared to my Mazda ladder plate 12AU7s. Love those Mazdas. Well those 12BH7s were up for sale, but not anymore. I put more time on those... Which I did before... A day or two... But I tried them for giggles, they were not bad. With more time, I think they equal my Mazdas for sure. I give the win to the 12BH7s by a hair. I think stage and space is better with the oval plates. So now my Mazdas are back to spares for my amp. And I think I picked up a bit of volume which is always good.

I just never assume NOS means not used. All my other tubes have never changed with any burn in. But they I would have made a big mistake. Even more real, more space, that incredible Mullard bottom end. So easy to listen to. So pleasing. Stopped comparing and lust listened to stuff for another hour. I'm officially done.
Burning in is very real, definitely not an imagination. The question is how much the sound will change over the course.
 
Jun 1, 2023 at 10:55 AM Post #8,885 of 10,650
Definitely... I've just never had any NOS that needed it. 24hrs, or 48...but never any difference. These were all like brand new. Heck I just got an actual brand new 274B from SE. I did burn that in for a couple hundred hours, but never had big changes.

I just tried a pair of ECC32s that were actually shot. It was clear and for the money I wasn't getting stuck so they went back. It was all up front, but certainly not because they needed time. All of these actually sounded good from the start. Just not great. The sound was all technically accurate, just lacking the tube secret sauce. It definitely came out. Lesson learned for sure. That space, depth, you can touch it realism. The blessings from the tube gods... 😂
 
Jun 1, 2023 at 11:13 AM Post #8,886 of 10,650
Jun 4, 2023 at 11:14 AM Post #8,887 of 10,650
I've recently bought a pair of Melz 1578 for my LTA MZ3 from Russia. One of the tubes is producing constant pops and crackles at rest and during playback. Can anything be done to salvage it, or into the bin?
 
Jun 4, 2023 at 12:03 PM Post #8,888 of 10,650
I've recently bought a pair of Melz 1578 for my LTA MZ3 from Russia. One of the tubes is producing constant pops and crackles at rest and during playback. Can anything be done to salvage it, or into the bin?
Resolder pin 7 and 8. If that doesnt fixed the issue, resolder the rest of the pins. Last resort, burn in the tube for hours or overnight and hope for the best. GL.
 
Jun 4, 2023 at 2:46 PM Post #8,889 of 10,650
Resolder pin 7 and 8. If that doesnt fixed the issue, resolder the rest of the pins. Last resort, burn in the tube for hours or overnight and hope for the best. GL.
Are they numbered clockwise from the fitting indicator on the central pin?
 
Jun 4, 2023 at 4:04 PM Post #8,890 of 10,650
Are they numbered clockwise from the fitting indicator on the central pin?
Yes, if the base of the tube is directly facing you. With the fitting indicator (guide key) facing down, pin 7 and 8 are just the last 2 pins to the right from the guide key. BTW, they are the heater pins. Nevertheless, if you wanted to do all pins at the same time, it is fine too.
 
Last edited:
Jun 4, 2023 at 5:52 PM Post #8,891 of 10,650
Are they numbered clockwise from the fitting indicator on the central pin?
Yup. As @TLO noted, with the key in the 6:00 position. As long as you've got everything out and set up, I'd suggest just doing all of the pins. If the solder is degraded in one pin as of now, it's logical the others won't be far behind. Seems the Russian tubes of this era have a high incidence rate of pin solder issues. Not just the Melz, but Fotons too.


1685915096979.png
 
Jun 4, 2023 at 6:30 PM Post #8,892 of 10,650
Yup. As @TLO noted, with the key in the 6:00 position. As long as you've got everything out and set up, I'd suggest just doing all of the pins. If the solder is degraded in one pin as of now, it's logical the others won't be far behind. Seems the Russian tubes of this era have a high incidence rate of pin solder issues. Not just the Melz, but Fotons too.


1685915096979.png
So am I just applying the solder to the pins, as though tinning a cable?
 
Jun 4, 2023 at 7:14 PM Post #8,893 of 10,650
So am I just applying the solder to the pins, as though tinning a cable?
You can do that (reheat the pin until the internal solder melts, and add a little fresh solder) but the best way is to heat each pin until the internal solder melts, suck out all the old solder, and then fully replace with new solder. You can certainly try the simpler method first and see if that solves the problem. There are several guides and how-to's posted on this, and I believe some are in this very thread. The Melz 1578 is certainly worth the extra effort to do it the best way, IMO.
 
Jun 4, 2023 at 10:11 PM Post #8,894 of 10,650
I've recently bought a pair of Melz 1578 for my LTA MZ3 from Russia. One of the tubes is producing constant pops and crackles at rest and during playback. Can anything be done to salvage it, or into the bin?
 
Jun 6, 2023 at 5:20 PM Post #8,895 of 10,650
Hi all!

I recently bought some nice Melz 1578 produced in 1963 for my Euforia amp. The seller said they were never used and they really look like new. As I started to test them I was amazed with their performance, way better than my previous Melz 6N8S, however later I discovered they produce a slight hum which is independent of the volume and constant in both channels. As with my previous Melz's I owned (that always came with some static noises, pops, etc....) I proceeded to clean all pins with a polish tool and then I re-soldered all pins but nothing changed :slight_frown:.

Any ideas what could be happening and how to solve it?

1686086329009.jpeg


1686086373256.jpeg
 

Users who are viewing this thread

Back
Top