The Reference 6SN7 Thread

[Ake_Y]

The first pair is from the 80s... if you like a brighter tube - great, but for me those are harsh tubes for a harsh price. The cheaper pair aren't actually 1578s, but 6H86s, and are mellower and to me more enjoyable than 1578s from the late 70s and 80s.

1950s 1578 here: https://www.ebay.com/itm/165653930700 - cheaper than $450 per pair... just have to buy a quad...

Thank you very much for clarification. However, the item you recommended from eBay sales in pair instead of quad per detailed description. Do you think the cheaper 6H86 is suitable for the price?

 

[ColSaulTigh]

I'm looking for a paired Melz 1578. I found these two, but the first's price ( 450 USD ) is around twice of the second's ( 250 USD ) . Please suggest which one I should pick. Thank you.

Can't see the details of the first pair enough to tell if they are 1578's. The second pair definitely are not.

I wouldn't buy either.

 

[ColSaulTigh]

From the number of 6F8G tubes I have, I prefer the National Union.

Those are good too! Surprisingly, you can find them cheaper than either the Tung Sol and Sylvania from time to time.

 

[David222]

Thank you very much for clarification. However, the item you recommended from eBay sales in pair instead of quad per detailed description. Do you think the cheaper 6H86 is suitable for the price?

A good Melz reference (start point) is @bcowen --> Post #7,938 of 9,003

You can see many Pro Tips from ColSaul and Paladin in the pages immediately thereafter

 

[bcowen]

The first pair is from the 80s... if you like a brighter tube - great, but for me those are harsh tubes for a harsh price. The cheaper pair aren't actually 1578s, but 6H86s, and are mellower and to me more enjoyable than 1578s from the late 70s and 80s.

1950s 1578 here: https://www.ebay.com/itm/165653930700 - cheaper than $450 per pair... just have to buy a quad...

My ears agree with yours on the later (1980+) years -- I'd rather have a standard 6N8S (6H8C) than a true 1578 from that time period. The 1950's and early '60's 1578's are the ones to have, with the '50's definitely being preferable, but the early '60's also sound very good. The '50's and early '60's standard 6N8S's also sound very good, just not to the same level as the 1578's of the same period.

The Ebay link is for 6N8S tubes, they just have perforated plates rather than solid ones. I haven't heard any of those myself. Might be very nice sounding tubes, but they aren't true 1578's which have the spring mica supports up top and narrow rectangular micas top and bottom (rather than oval). Seems Melz mixed those plate styles back and forth at some points as you can also find 1578's with solid plates, although those are quite rare. I've never had one, but @Paladin79 has at least one the last time I checked. That was a while back though so he may have several thousand by now.

Seems like everyone selling a Melz 6N8S these days adds the 1578 label, just like people were labeling every Sylvania 6SN7 a Bad Boy a while back.

 

[Paladin79]

My ears agree with yours on the later (1980+) years -- I'd rather have a standard 6N8S (6H8C) than a true 1578 from that time period. The 1950's and early '60's 1578's are the ones to have, with the '50's definitely being preferable, but the early '60's also sound very good. The '50's and early '60's standard 6N8S's also sound very good, just not to the same level as the 1578's of the same period.

The Ebay link is for 6N8S tubes, they just have perforated plates rather than solid ones. I haven't heard any of those myself. Might be very nice sounding tubes, but they aren't true 1578's which have the spring mica supports up top and narrow rectangular micas top and bottom (rather than oval). Seems Melz mixed those plate styles back and forth at some points as you can also find 1578's with solid plates, although those are quite rare. I've never had one, but @Paladin79 has at least one the last time I checked. That was a while back though so he may have several thousand by now.

Seems like everyone selling a Melz 6N8S these days adds the 1578 label, just like people were labeling every Sylvania 6SN7 a Bad Boy a while back.

I own several of the solid plate version, I rarely get any background noise with those. I could have sworn I loaned you one of those to hear. There would have been some severe threats involved to insure I got it back but maybe such things are common place for you. Maybe one day I will gift you one; today is not the day. Oh and they need to have shiny black plates, the dull grey plate version is ok but just not as detailed IMHO.

 

[bcowen]

I own several of the solid plate version, I rarely get any background noise with those. I could have sworn I loaned you one of those to hear. There would have been some severe threats involved to insure I got it back but maybe such things are common place for you. Maybe one day I will gift you one; today is not the day. Oh and they need to have shiny black plates, the dull grey plate version is ok but just not as detailed IMHO.

No, you never loaned me one of those. If you had, you know I would have returned it by next year. Geeez.

 

[mordy]

Those are good too! Surprisingly, you can find them cheaper than either the Tung Sol and Sylvania from time to time.

And you can find rebranded NU even cheaper. The tip off is a little loop on the anode cap wire between the top mica and the glass which is unique to NU.

 

[Paladin79]

No, you never loaned me one of those. If you had, you know I would have returned it by next year. Geeez.

Ok I will look though my collection and see what I can do. Finding one now is very difficult, a few years back I might find one every six months. I have plenty for my Incubus amps and since getting a PrimaLuna I do not run my Freya much.

 

[Novik tube]

When a tube turns white it means that it lost it’s vacuum and the silvery getter flash reacts with the air and turns white.
The tube has developed a crack in the glass envelope and becomes useless.
In my experience the cause for most tubes that stop functioning is being dropped and breaking .
There are reports of people using the same tubes for over 20 years.
Most tubes are rated for 3000-5000 hours, and some for 7500-10000 hours.
However, many of these ratings refer to military use under harsh conditions; usually the tube amps we use put much less stress on the tubes.
Beware of unscrupulous dealers that claim that you must change the tubes after 1000 hours!
It is also important to know that tube measurements aren’t as crucial as some people may want you to think - you may not be able to hear any difference between a tube measuring NOS and one measuring barely good!

I'm trying to learn the opinion of the participants in this forum related to the operation of tubes and, especially, with tubes rolling.
I can add that my personal experience (more than 40 years of guitar tube building) confirms your statement about a very large (almost) unlimited time of work
tubes in the input (signal) circuits! But this statement applies mainly to NOS lamps and especially for military applications! Claimed 500,3000 and more than 10,000) in amplifiers, no one has ever checked! This does not apply to Chinese tubes and other new products !

Also, completely different requirements for and service life for power tubes and kenotrons!

Checking and testing input tubes makes sense on a professional tester, not one that says good or bad (home versions)

If you have an amplifier with an SRPP cascade, it is desirable to have balanced (with close halves) tubes (you won’t pick them up by ear)

 

[tameral]

Until one of ya'll is willing to see sell me a pair of 50s Melz to compare - I'm just gonna have to assume ya just don't have the chain / headphone to handle the technical (treble) superiority of the 70s Melz

 

[Paladin79]

Until one of ya'll is willing to see sell me a pair of 50s Melz to compare - I'm just gonna have to assume ya just don't have the chain / headphone to handle the technical (treble) superiority of the 70s Melz

I would rather just let you live with that assumption. I designed the amps used for 6sn7 comparisons I conducted. Others can tell you if that amp allowed them to hear differences; I run Focal Utopias myself but most tests were performed with Senn HD800’s. I also prefer basing SQ on what large groups of people hear, usually fifty or so. Source music was recorded to show off said differences.

 

[tameral]

HD800? Treble peaks galore. Non-natural sound. Enough said.

 

[Paladin79]

HD800? Treble peaks galore. Non-natural sound. Enough said.

Yep you are right and 35 members of my local group are wrong. Enjoy your 70’s Melz, each to their own.

 

[tameral]

I don't think you detected the kiddingness of my first post - I imagine the 50s Melz are better and was jokingly asking for somebody to sell me a pair. That being said, my response about the HD800 is dead on from my perspective as a testing instrument. Regards