[Johnnysound]

   
199 (or 1199) indicates the type. Please see the following link.
 

1. http://myweb.tiscali.co.uk/g8hqp/audio/brimarcodes.html

 
They are Brimars. There is no mystery. 

 
 
Yes:
 
 

 
Yes, I think so.     Following that mysterious Brimar codes, 2G5 indicates the  date,  should be 2nd. week of july, 1955 or 1965,  and the 1199 should mean a 6AU6 tube type.    Sadly,  the 1199 = 6AU6 code does not appear in the list  provided, but this is an incomplete list  and that number  is not assigned to any other tube... 

 

[Uncle AL]

The second amplifier?

I'd try a gain of 5 and see what you think, right now you have it set to 3.

First MK IV SE returned on warranty due to finish problem. LD responded well and sent replacement, but amp has much lower output. Set gain to 5, ON-OFF. Volume must be set to 50 (12 O'Clock) for comfortable listening. Audio quality is excellent. Just lower than expected output.

 

[Oskari]

I had forgotten all about those 6J4Ps...

 
Rest assured that Google will not forget. An image search for ef94 russian handily delivered that photo of yours.

 

[Oskari]

  Yes, I think so.     Following that mysterious Brimar codes, 2G5 indicates the  date,  should be 2nd. week of july, 1955 or 1965

 
Somehow 65 seems more plausible to me.

 

[i luvmusic 2]

I was about to Butcher my MK III for the socket adapters then i changed my mind so i end up doing this instead installed 4 Pin XLR socket and upgrade the Electrolytic Caps to Film Caps.

 

[Acapella11]

A few questions to all the 6SN7 users if you don't mind: Do you find a great difference in SQ between the 6SN7 tubes? Which is your favourable tube and why? And which is the most transparent/detailed one?

 

[jazzwave]

A few questions to all the 6SN7 users if you don't mind: Do you find a great difference in SQ between the 6SN7 tubes? Which is your favourable tube and why? And which is the most transparent/detailed one?

 


My fav so far Sylvania VT-231

Some user said VT-231 Tung-Sol, round black plates is the best

6sn7-tube-addicts
http://www.head-fi.org/t/479031/6sn7-tube-addicts


~ron~

 

[MIKELAP]

A few questions to all the 6SN7 users if you don't mind: Do you find a great difference in SQ between the 6SN7 tubes? Which is your favourable tube and why? And which is the most transparent/detailed one?

As power tube in LD or in general ?

 

[mordy]

Hi A11,
 
With the risk of rousing the ire of the 6SN7 "addicts", my favorite 6SN7 is a 1960's RCA with a thin heater wire on top. Haven't found anybody mentioning this tube anywhere. If you are lucky (or diligent/patient) you can find these for a few dollars.
 
That said, I have not tried the exotic and expensive 40's tubes - so I cannot really compare with the $100 tubes.
 

This tube is a rebranded RCA with the name Hoffman. If you look carefully you can see the little wire on top. These tubes are nice as drivers as well as power tubes.

 

[Acapella11]

 

A few questions to all the 6SN7 users if you don't mind: Do you find a great difference in SQ between the 6SN7 tubes? Which is your favourable tube and why? And which is the most transparent/detailed one?

My fav so far Sylvania VT-231

Some user said VT-231 Tung-Sol, round black plates is the best

6sn7-tube-addicts
http://www.head-fi.org/t/479031/6sn7-tube-addicts

~ron~

 

  Hi A11,
 
With the risk of rousing the ire of the 6SN7 "addicts", my favorite 6SN7 is a 1960's RCA with a thin heater wire on top. Haven't found anybody mentioning this tube anywhere. If you are lucky (or diligent/patient) you can find these for a few dollars.
 
That said, I have not tried the exotic and expensive 40's tubes - so I cannot really compare with the $100 tubes.
 

This tube is a rebranded RCA with the name Hoffman. If you look carefully you can see the little wire on top. These tubes are nice as drivers as well as power tubes.

 
Dear jazzwave and Mordy, thank you for the answers, it would be nice if collect a few more suggestions. I will look out for the tubes mentioned above.
 
 

  As power tube in LD or in general ?

 
Hi Mikelap, as power tube mainly. Although I would hope that the priority list as driver tubes would be the same with the only difference being that the matching would change of course.

 

[siles1991]

wow how long has it been xD I'm still using my RCA 6DT6A, thinking of trying get more outta from my MKIV SE now ! What direction should I take! Hopefully something that a electronically challenged person like me can handle.

 

[gibosi]

A few questions to all the 6SN7 users if you don't mind: Do you find a great difference in SQ between the 6SN7 tubes? Which is your favourable tube and why? And which is the most transparent/detailed one?

 
In my experience there are significant sonic differences among the 6SN7, not only between brands, but also within the same brand over the years. And in fact, there are differences between 6SN7 manufactured by the same company at the same time. Here I am referring to Sylvania, which manufactured Chrome Domes, VT231's and the three-hole Badboys all at the same time.
 
That said, nearly all these tubes are very fine. And I think it is safe to say that any of these can shine in the right system. Again, it really comes down to synergy. So I would expand on Mordy's advice and suggest that you try several cheap pairs: For example, RCA, Tung-Sol, Sylvania, Raytheon, CBS/Hytron, National Union, and Hitachi, to help you find your favorite brands. And then, as I believe that the 1940's and early 1950's are the best, you might want to try some of these earlier tubes.
 
Used as drivers, my favorite is the 1940's Sylvania 6SN7W. However, the early 1950's Chrome Dome provide a sound that is quite close, lacking just a little warmth. Paired with a relatively warmer driver, they could be great.

 

[bbmiller]

 

A few questions to all the 6SN7 users if you don't mind: Do you find a great difference in SQ between the 6SN7 tubes? Which is your favourable tube and why? And which is the most transparent/detailed one?

As power tube in LD or in general ?

 
Quote:

6sn7-tube-addicts
http://www.head-fi.org/t/479031/6sn7-tube-addict

 

I too have been finding your answers to Acapella11 question very informative! I have particularly found  jazzwave  link to the other forum very good! Which led me to some browsing on my own to answer the question in regard to inexpensive power tubes. Which eventually led me to the criteria set out by this person below.

 

RE: Inexpensive Sylvania 6SN7GTA​

67.84.135.83​

1. Posted by Neff on July 18, 2010 at 05:07:58 In Reply to: RE: REVIEW: Tung-Sol 6SN7GTB Tubes posted by steven d on July 17, 2010 at 05:05:28:
    

Look for Sylvania manufacture with a Motorola or Silvertone label. I bought 6SN7GTA in NOS for $12-$15 each. 

The 'Y' plate tubes were manufactured in both short & tall glass. An identifier that guarantees Sylvania manufacture is that 'Y' shape plate construction and I prefer the 'Y' plate design over the standard rectangle shape plate design. As another identifier at times is the Silvertone & Motorola label has the Sylvania 312 manufacturing code printed on the tube.

The 6SN7GTA are more rare than 6SN7GTB, but guarantees early 1950s manufacture. If one can identify a date code, the 6SN7GTB are good to approximately 1957. Later tubes in the 1960s are sonically different to my ears and less of a performer vs the earlier manufactured tubes.

With each leads me to further wonder if one wanted to go with the criteria set out by the person above could any of you all give me a link to a good seller that would definitely meet all criteria set forth by the person above for a 6SN7GTA(or a before 1957 6SN7GTB) including a fair price?

Also I do not know how in eBay I managed to generate this link "Showing items imilar to... Two 6SN7 GTA/GTB  Sylvania Angle Plate Chrome Top Two 6SN7 GTA/GTB Sylvania Angle Plate Chrome Top "Reference Graded Pair"  but I am wondering if angle plates are the same as  'Y' plate in the person above criteria?
 
One more also if I may further beg you all's indulgence? If none of you could send me to the type of seller I desire you to link me to could you give me some criteria and how to find a seller that meets all those criteria. I mean will I have to write to eBay sellers and hope they will explicitly answer me in a timely manner or are there other better ways to ensure a seller meets a list of criteria for the tube they are selling?

 

[gibosi]

  I too have been finding your answers to Acapella11 question very informative! I have particularly found  jazzwave  link to the other forum very good! Which led me to some browsing on my own to answer the question in regard to inexpensive power tubes. Which eventually led me to the criteria set out by this person below.
With each leads me to further wonder if one wanted to go with the criteria set out by the person above could any of you all give me a link to a good seller that would definitely meet all criteria set forth by the person above for a 6SN7GTA(or a before 1957 6SN7GTB) including a fair price?

Also I do not know how in eBay I managed to generate this link "Showing items imilar to... Two 6SN7 GTA/GTB  Sylvania Angle Plate Chrome Top Two 6SN7 GTA/GTB Sylvania Angle Plate Chrome Top "Reference Graded Pair"  but I am wondering if angle plates are the same as  'Y' plate in the person above criteria?
 
One more also if I may further beg you all's indulgence? If none of you could send me to the type of seller I desire you to link me to could you give me some criteria and how to find a seller that meets all those criteria. I mean will I have to write to eBay sellers and hope they will explicitly answer me in a timely manner or are there other better ways to ensure a seller meets a list of criteria for the tube they are selling?

 
1) The first thing I look at is the seller information block. If a seller has 500 or more transactions and a positive feedback rating of at least 98%, I consider them to be a reliable seller. I have purchased over 800 tubes from many, many different sellers, world wide, and have had only a handful of problems, and even then, these problems were resolved by the seller, or in one case, by eBay, to my satisfaction.
 
2) You need to learn how to recognize the construction used by Sylvania (or any other tube you are considering.). There is no shortcut. In the end, you need to spend a fair amount of time examining as many pictures as you can find.
 
3) And then, armed with this knowledge, when you find a tube(s) you are interested in, examine the pictures very closely. If the pictures are poor, ask the seller to provide better pictures. In the case at hand, 6SN7GTA should be clearly seen on these tubes. The plate style should be easy to determine. And the date codes should be visible. If not, and the vendor is not cooperative, go elsewhere. Searching for "sylvania 6SN7" today yielded almost 600 listings. These tubes are not rare. Take your time. And don't pull the trigger until you are convinced you are buying exactly the tubes you want. 
 
Cheers

 

[gibosi]

Well, on the chance that some of you are getting bored with the current tubes, I humbly suggest another group of twin triodes:
 
6350
6463/CV5404/CC86E and
ECC813
 
Evidently these tubes are used in the Audio Note, Ongaku, M8, M9+
 
6350
 
The 6350 are the most common tubes in this group:
 
RCA 1959                                                                                 Sylvania (IBM) 1957
 

 
The 6463's are less common. That said, there appear to be a ton of GE's, and much more rarely, Philips and Telefunken.
 
And finally, the ECC813 appears to have been manufactured only by RFT.
 
These tubes are similar to the 12AU7 and 5687 groups in that they have a center tap allowing their use in both 12 and 6 volt systems. However, the pin-out is different than any other tube I have tried. Essentially, it is the 12AU7 pinout with the cathodes and grids swapped out:
 
 9 Pin socket                                 Left LD socket                    Right LD socket
 
1 plate section 2                                                                                   5
2 cathode section   2                                                                            2
3 grid section 2                                                                                    1
4 heater - external PS                                                                           
5 heater -tie to 4                                    
6 plate section 1                                        5
7 cathode section 1                                   2
8 grid section 1                                         1
9 heater center tap to external PS
 
Have fun!