The Reference 6SN7 Thread

[leftside]

As a neophyte tube amplifier owner, I have another question.

I noted that you stated that you have older tubes that test low, but sound better than new NOS 100% testing tubes.

That made me wonder about decision-making choices when buying tubes from an e-bay seller.

For example, let's presume that I decided to purchase a pair of Sylvania V231 6sn7GT tubes for my Cayin HA300MK2 headphone amplifier.

Here is a listing for an used set for $174 for a matched pair - https://www.ebay.com/itm/225287178877?epid=1729696074&hash=item3474298a7d:g:oAwAAOSwQ2djkXny

I noted that the seller had another set that was labelled brand new, that was selling for $358 for a matched pair.

What are the pros and cons of buying the used set versus the brand new (unused) set?

Jeff.

Easy decision for me. I'd go for the $174 pair and use them. Those are GREAT tubes btw. Definitely one of my favorite 6SN7 and I often use them in my preamp. I prefer them over the earlier and more expensive metal base version.

The newer version will hold their price much better as long as you don't use them. Collectors pieces. I have lot's of tubes I use, but I also have a few NOS/NIB tubes that I will never use. I consider these to be more antiques/historical artifacts.

Edit: Just beware the tube on the right has seen a lot of use. I can tell by just looking at the top of the glass. A new tube of that type will be completely clear. The base has also seen better days. After looking at the pictures, I wouldn't buy this pair of tubes.

 

[LobalWarming]

Hmm, I have never found them to be dark at all but in terms of being darker than the Melz unfortunately I have never heard the Melz. I think these particular Tung Sol’s are excellent and to my ears are very neutral and detailed with lots of spatial qualities and excellent bass. They don’t have the rich tonality as many other tubes but they are not dry and cold like later tubes. Their sibling, the mouse ears version of this tube, is even a tad more detailed but to me but just a hair brighter as well and huge spatial qualities.

Agree, my TS 6SN7s aren't dark sounding - GTs/GTB. Very clean and balanced. Agree mouse ears are a little brighter.

I have different vintages of Melz 1578 - and the tonal balance changes across the decades (with the decades?) The ones from the 50s ('55/'57) have a warmish balance, with delightful lush presentation - for me, the most enjoyable. The 60s versions are more detailed/brighter - a little less enjoyable. The 70s - too bright for me and only blend well when I cover my amp in fluorescent orange shag.

Compared to a 70s Melz, a 50s TS 6SN7 could indeed sound dark, or as I like to say, correct.

 

[g0ldl10n]

As a neophyte tube amplifier owner, I have another question.

I noted that you stated that you have older tubes that test low, but sound better than new NOS 100% testing tubes.

That made me wonder about decision-making choices when buying tubes from an e-bay seller.

For example, let's presume that I decided to purchase a pair of Sylvania V231 6sn7GT tubes for my Cayin HA300MK2 headphone amplifier.

Here is a listing for an used set for $174 for a matched pair - https://www.ebay.com/itm/225287178877?epid=1729696074&hash=item3474298a7d:g:oAwAAOSwQ2djkXny

I noted that the seller had another set that was labelled brand new, that was selling for $358 for a matched pair.

What are the pros and cons of buying the used set versus the brand new (unused) set?

Jeff.

Also, I would look around for auctions of tubes you're interested in, as you can often times end up getting them for a bit cheaper than the non auction listings.

Found one you might like here, with about 29 hours left.

https://www.ebay.com/itm/3641106728...pEQbXGpSsq&var=&widget_ver=artemis&media=COPY

 

[ejk1]

What happened when a tube roller discovered that his amp has enough space for not one, not two but three dual adapters after all? Did he go crazy? No, he celebrates his Christmas in July...





Hmm...this is what I called fun

I've been reading this thread and keep seeing these adapters but can't seem to find what they are. Can someone fill me in please

Thanks

 

[bcowen]

I've been reading this thread and keep seeing these adapters but can't seem to find what they are. Can someone fill me in please

Thanks

In general, they are for adapting single triode tubes into a socket originally wired for a dual triode. Many different varieties, the one below is a homebrew for a pair of single triode 6J5's to plug into a (single) socket for a dual triode 6SN7. The ones @TLO is showing are for single triodes that also have external plate and/or grid connections, thus the additional external wires.

 

[ejk1]

Thanks

 

[TLO]

I've been reading this thread and keep seeing these adapters but can't seem to find what they are. Can someone fill me in please

Thanks

The very basic function of an adapter is to relocate the pin position of a tube to certain position or change of base types (e.g. octal 8 pins to noval 9 pins or vice versa), so an alternative tube can be used.
For example, below is the pin position of a 6SN7 GT as follow...which my amp is originally designed to use on each channel.

Pin 1 - grid 2
Pin 2 - anode 2
Pin 3 - cathode 2
Pin 4 - grid 1
Pin 5 - anode 1
Pin 6 - cathode 1
Pin 7 - heater
Pin 8 - heater

Now, what if I wanted to use tubes other than 6SN7....say EL32 (a pentode)

You will notice not only the position of the pins are different but it (a pentode) also has 3 grids for 1 anode compared to 1 grid for each anode on the 6SN7 (a dual triode). You will convert the EL32 to a single triode (for triode strapping, read the attachment), and run them in pair like a dual triode 6SN7 by using a ready made dual adapter which also relocate the pins to the correct position as 6SN7 at the same time...or you can simply make your own adapters.

EL32 (Pentode) to Triode

1st pair - Noval 9 pins to Octal 8 pins
2nd pair - Double Diode Triode to Triode

1st pair - Noval 9 pins to Octal 8 pins
2nd pair - Triode Hexode to Triode

Tip: If the 6SN7 sockets are parallel connected between the 2 sections within the tube, you might consider using a single tube instead of running them in pair, as I find them sound better as single in my setup. YMMV.

FINAL NOTE: always study the datasheet carefully when rolling tubes and stay within the specs of the amp for safety.

 

[LoryWiv]

The very basic function of an adapter is to relocate the pin position of a tube to certain position or change of base types (e.g. octal 8 pins to noval 9 pins or vice versa), so an alternative tube can be used.
For example, below is the pin position of a 6SN7 GT as follow...which my amp is originally designed to use on each channel.



Pin 1 - grid 2
Pin 2 - anode 2
Pin 3 - cathode 2
Pin 4 - grid 1
Pin 5 - anode 1
Pin 6 - cathode 1
Pin 7 - heater
Pin 8 - heater

Now, what if I wanted to use tubes other than 6SN7....say EL32 (a pentode)

You will notice not only the position of the pins are different but it (a pentode) also has 3 grids for 1 anode compared to 1 grid for each anode on the 6SN7 (a dual triode). You will convert the EL32 to a single triode (for triode strapping, read the attachment), and run them in pair like a dual triode 6SN7 by using a ready made dual adapter which also relocate the pins to the correct position as 6SN7 at the same time...or you can simply make your own adapters.



EL32 (Pentode) to Triode


1st pair - Noval 9 pins to Octal 8 pins
2nd pair - Double Diode Triode to Triode


1st pair - Noval 9 pins to Octal 8 pins
2nd pair - Triode Hexode to Triode


Tip: If the 6SN7 sockets are parallel connected between the 2 sections within the tube, you might consider using a single tube instead of running them in pair, as I find them sound better as single in my setup. YMMV.

FINAL NOTE: always study the datasheet carefully when rolling tubes and stay within the specs of the amp for safety.

Thanks, as a non-technical end user this explanation is very helpful. In Feliks-Euforia AE I often use tetrodes (6V6, 6L6, KT88) or pentodes (EL3N, EL-11) with adapters, only 1 tetrode or pentode per socket. Would there be any advantage to using double adapters to run 2:1 or is the Euforia an example of the parallel socket configuration you reference above in which 1:1 sounds better?

 

[keenerz]

Kind of shocked this tube has not been talked about much in this thread. . .



RFT 6SN7 Welded Plates w/Ceramic Spacers and Dual Foil Cup Getters - Best bass I have heard from a 6SN7 that slams and has detail and texture like no other, mids that are clean and clear with transparency through the roof and vocals that are huge/forward and project out in front, with highs that sparkle and really good staging as well. Overall, it's very well balanced with outstanding dynamics and works extremely well paired up with some Elrog ER300B's, and makes my ZMF's sing to their full potential. The RFT is quite rare and expensive at the moment, but can be found from time to time for around $350 a pair if you are diligent in your search. I love this tube so much I have 5 pairs, and hopefully they last me until a can't hear anymore.

Of note there is a latter version, with a single foil getter and stapled plates and it's does not have the magic of the earlier version, and is not worth the current asking price.

You inspired me to look for one, giving it a good warming right now.

 

[TLO]

Thanks, as a non-technical end user this explanation is very helpful. In Feliks-Euforia AE I often use tetrodes (6V6, 6L6, KT88) or pentodes (EL3N, EL-11) with adapters, only 1 tetrode or pentode per socket. Would there be any advantage to using double adapters to run 2:1 or is the Euforia an example of the parallel socket configuration you reference above in which 1:1 sounds better?

Not sure as I have no knowledge on this mentioned amp....nevertheless, after checking, I found out that the input stage is using a pair of 6SN7 (a dual triode). Physically, below is the image of how a parallel connection between the 2 sections look like (both cathodes, both grids and both anodes are connected to each other, hence the final setup is just like a single section triode tube...e.g. 6J5G, CV6, etc...

those two with the red wires are parallel connected.

There are 3 simple ways to check
1. look at the schematic of this amp
2. open up the amp and check the wire connections on the sockets (like shown above)
3. use a multimeter to check for continuity on pin 1 n 4 / 2 n 5 / 3 n 6

As for the pro n con of using single or in pair, there is no definite or simple way but to experiment them yourself due to various factors.
Good luck but most importantly, have fun!!!

 

[keenerz]

now if I can find a dang "real real" 1578 melz tube I can be happy lol

 

[mordy]

Thanks, as a non-technical end user this explanation is very helpful. In Feliks-Euforia AE I often use tetrodes (6V6, 6L6, KT88) or pentodes (EL3N, EL-11) with adapters, only 1 tetrode or pentode per socket. Would there be any advantage to using double adapters to run 2:1 or is the Euforia an example of the parallel socket configuration you reference above in which 1:1 sounds better?

As far a I know the Euforia uses two 6SN7 tubes in parallel. Felix Audio claims that this gives better sound. IMHO one dual triode is enough to get good sound - perhaps having two in parallel has more to do with aesthetics?

 

[moosemp]

I use Euforia 20 ANNIVERSARY with standard tubes supplied. Sound is nothing but spectacular. I once tried vintage Brimar 6sn7 but was not satisfied. Sounded muddy and rolled in treble. I wonder what tubes would you use For eventual rolling?

 

[JTbbb]

I use Euforia 20 ANNIVERSARY with standard tubes supplied. Sound is nothing but spectacular. I once tried vintage Brimar 6sn7 but was not satisfied. Sounded muddy and rolled in treble. I wonder what tubes would you use For eventual rolling?

Hmm, how strange. I’ve had your set up before and found the Brimar CV1988 to be excellent. What Brimars did you try? Also, I found the replacement of the power tubes to be a bigger bang for your buck. Tungsol 5998’s will make a big upgrade, but lesser 6AS7’s should beat the standard tubes. All IMHO of course! Edit: Those standard drivers are good.

 

[Isaacc7]

Wonder if anyone can help with some info about some Brimar 12sl7 tubes that I have. Been looking for some extras but can’t find any exact matches and I don’t understand the codes. Here’s the first one:

The round Micas are throwing me. Haven’t seen other Brimar *sl7 with them. Any idea what the codes mean? Also notice the distinctive “T” construction at the bottom? Haven’t seen that on any of the Brimar or STC 6sl7 listed on Langrex or ebay. But I do have another Brimar 12sl7 with the “T”

There is a “1” on the other side of the Brimar logo. This tube has the more typical oval mica. And while the plates look similar, they are shorter than the first one. And to add more intrigue, here’s a 12sl7 labeled Tungsram Made in England.

The mica looks the same as the last one, it has the “T” structure underneath, and the plates look the same except the Brimar are black and the Tungsram are grey. I can’t find any codes on the Tungsram. Has anyone else seen similar tubes and does anyone have any idea where and when these were made?