[gibosi]

  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.

 
I think I cannot emphasize too much how important it is that you take the time to study the construction of these tubes. You simply cannot count on most vendors to know what it is they are selling. It is not that they are dishonest, they just simply don't know. For example, sometimes you will see a pair of Mullard 6SN7GT, made in England on eBay for a hefty price. Well, Mullard NEVER EVER manufactured the 6SN7GT. Moreover, a close examination of the pictures reveals flying saucer getters! Maybe these tubes were manufactured in England, but if so, Russian factory equipment was used. The vendor simply doesn't know what he has.... And I pity the poor soul who spends the big bucks for these "Mullard" tubes. The only way you can be sure you are getting the real deal is to do your homework.
 
Cheers

 

[sgbwill2]

  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!

Why tempt me with more tubes! haha. Just received my 5687 GR 5 star's today(1961-62) and am extremely happy with them. Upgrade to 6f8g and 6sn7's to my ears, and there is no base distortion now at all allowing me to listen to the LD with low impedance headphones finally! As I am enjoying these tubes so much I will most likely purchase some more 12.6v tubes which you have just stated. My poor wallet

 

[stvn758]

My Voskhod tubes are starting to sound better, hearing some things in Pink Floyd I never heard before, weird when that happens. My 6HM5 EC900 EI Yugoslavia also arrived today, must remember I need to set the jumpers before using them. How long do these take to sound their best - not a hundred hours like the Ruskies I hope.  

 

[gibosi]

  Why tempt me with more tubes! haha. Just received my 5687 GR 5 star's today(1961-62) and am extremely happy with them. Upgrade to 6f8g and 6sn7's to my ears, and there is no base distortion now at all allowing me to listen to the LD with low impedance headphones finally! As I am enjoying these tubes so much I will most likely purchase some more 12.6v tubes which you have just stated. My poor wallet

 
Not too fast!!  I have yet to find a suitable adapter to allow these tubes to be used in a stock LD power tube socket. All I have found to date are 6463 to 6SN7 which could then be plugged into the 6SN7 adapters you were using.
 
Inserting two adapters between tube and socket is certainly not optimal or pretty, but it would work....  

 

[sgbwill2]

   
Not too fast!!  I have yet to find a suitable adapter to allow these tubes to be used in a stock LD power tube socket. All I have found to date are 6463 to 6SN7 which could then be plugged into the 6SN7 adapters you were using.
 
Inserting two adapters between tube and socket is certainly not optimal or pretty, but it would work....  

Seems I am too eager haha. hopefully there are some suitable adapters out there as I would very much like to try some of these

 

[bbmiller]

 

  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 above.
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

OK - I don't know if you think asking this is less than kosher because it is continuing to ask for a shortcut, but is there anything like a picture guide to the parts of the tube you need to know in all their variations or even some of their variations?
 
I also know the basic parts of the tube are the plate (cathode), grid, anode, and heater. But are there other parts of tubes I need to know about? You mentioned the getter for example are there still other parts?
 
After I know all the part names I would want to know about to learn about say Sylvania  6SN7 GTA/GTB do I simply use the part names like say "gathers in all their variations" in image search engines or are there better searching strategies you all who have already gone through the process could suggest? Did Sylvania back in the day put out guides to that big deal at the time tubes and explain their tube constructions and their variations complete with the names of specific part variations you could explicitly search for in image search engines?

 

[Nic Rhodes]

aren't 6463 part of the ECC86 family?

 

[jazzwave]

Quote from some sites, 6SN7 option, in general.

http://flagshipaudio.blogspot.com/2009/07/getting-best-sound-out-of-6sn7-tubes.html

http://vinylsavor.blogspot.com/2014/02/tube-of-month-6sn7.html

http://www.wiredstate.com/forum/viewtopic.php?t=8265&f=11

But its depend on your amp design, some time cheaper tube deliver better sound than the expensive one.
So, try directly in your system,listen the sound is the best way.

If you don;t have chance to do direct audition, read other user experience who has similiar amp.
But sometime not mach with your taste, one person said good but other probably say ;well this tube is good but not enough bass..


Good luck and enjoy with your 6SN7 adventure

~ron~

.

 

[gibosi]

  aren't 6463 part of the ECC86 family?

 
The 6GM8/ECC86 is often suggested as a replacement for the 6463. However, the pinout is different. The 6GM8/ECC86 has the same pinout as a 12AU7, whereas the pinout of the 6463 swaps the cathode and grid assignments. Moreover, when I read the data sheets, it seems to me that these tubes were designed for different uses. The 6463 is a 10,000 hour tube designed for use in computer circuits. The 6FM8/ECC86 appears to have been designed for use as a VHF amplifier and mixer for use in automobile radio sets. 
 
Even so, for those who are setup to run 12AU7 tubes, the 6GM8/ECC86 might well be worth trying.

 

[Nic Rhodes]

Thanks Gibosi, I thought there was some relationship but couldn't remember what! Checking my stock I just have mostly GE and some Telefunken 6463s but have never used them in anger yet.

 

[gibosi]

  OK - I don't know if you think asking this is less than kosher because it is continuing to ask for a shortcut, but is there anything like a picture guide to the parts of the tube you need to know in all their variations or even some of their variations?
 
I also know the basic parts of the tube are the plate (cathode), grid, anode, and heater. But are there other parts of tubes I need to know about? You mentioned the getter for example are there still other parts?
 
After I know all the part names I would want to know about to learn about say Sylvania  6SN7 GTA/GTB do I simply use the part names like say "gathers in all their variations" in image search engines or are there better searching strategies you all who have already gone through the process could suggest? Did Sylvania back in the day put out guides to that big deal at the time tubes and explain their tube constructions and their variations complete with the names of specific part variations you could explicitly search for in image search engines?

 
References such as these might exist, but if they do, I don't know about them....
 
In the end, "a picture is worth 1000 words". For example, these are the tubes that gave rise to the "Chrome Dome" moniker. They were manufactured in the late 1940's into the early 1950's by Sylvania. You will notice that the shiny getter splash is kind of dirty. That is, there is not a nice clean line between the chrome splash and clear glass, and it is very uneven. Further, the getter splash covers more than 1/2 of the bottle. The later Sylvania tubes, with clean and neat getter splashes, covering only the very top of the tube are different, and in my opinion, not as good. 
 
There are some physical differences among the Chrome Domes, but to my ears they all sound the same. So my conclusion is short base, tall base, 2-hole plates, 3-hole plates, all these late 1940's / early 1950's heavily chromed Sylvanias are virtually the same tube.
 
Sylvania 6SN7GTs 1952 (left) and 1949 (right)
 
Most have 3-hole plates, but the 1949 tube has 2-hole plates and bottom mica similar to the 6SN7W. Also, you will notice that one has a short base while the other has a taller base.
 

 
 
Sylvania 6SN7GTAs, both 1953
 
 

 

[mordy]

Hi G,
 
"the shiny getter splash is kind of dirty. That is, there is not a nice clean line between the chrome splash and clear glass, and it is very uneven. Further, the getter splash covers more than 1/2 of the bottle."
 
Thank you for clarifying this. Checked my inventory of Sylvania 6SN7 tubes. Found one real chrome dome from 1953, but the other tubes I have from 1954, 1955 and 1957 with a chrome top are not chrome domes. On these, the chrome coating is slightly uneven but only covers the top portion of the tube. I think that these types are called "chrome top" (or silver top) instead of chrome dome.
 
Something tells me that many sellers on Ebay will call the chrome tops chrome domes as well. And some will say that the 2 hole (or three hole) tube is the tube to have. Depends on how many you have to sell I guess...
 
Anyhow, I am now in C3g land and exploring. They sound very good, kind of 5687 on steroids - they have more of everything. Have to get used to these tubes and try a few power tube combinations until I can form a detailed opinion. But it really seems that they are as great as people say.
 
Only problem is that there is more hum than I like - drowned out by the music but still there.

 

[TrollDragon]

I dislike HUM on any level, even if it is drowned out by the music. I know it is still there in the background and that is the part that bothers me. Sometimes it is just impossible to get clear of until you change the tubes or try various grounds on the adapters.

 

[mordy]

Hi TD,
 
At normal to loud  listening levels I do not hear any hum, but cranking up my system very loud (beyond normal listening levels) there is always some hum. However, with these Cg3 tubes the hum appears much earlier, even at normal listening levels.
 
Would appreciate it if you could tel me how to ground the adapters.

 

[MIKELAP]

  I dislike HUM on any level, even if it is drowned out by the music. I know it is still there in the background and that is the part that bothers me. Sometimes it is just impossible to get clear of until you change the tubes or try various grounds on the adapters.

Should get the c3g tubes  next week hope theres no hum with adapters ,i tried to insulate heater wires to see if that helps will see soon enough.