[hypnos1]

  You would not believe the problems i had .

 
Oh yes I would!!

 

[MIKELAP]

   
Oh yes I would!!

I still have to write it on here lol hope for the best as the saying goes .

 

[MIKELAP]

Oups

 

[mordy]

Hi G,
 
As I remember, your Sylvania 6SN7W has a metal base. Those tubes are selling for well over $100 today. whereas the 5687 Sylvania can be found today for less than a quarter of that price ( and occasionally you can find them for $8 or less).
 
I realize more and more the importance of synergy and matching re driver tubes and power tubes. It seems that each tube will influence the other in terms of the sound. It could be that a good power tube will bring out new higher levels of performance from a good driver tube. In general I found that a good driver tube will make for a good power tube, BUT, if it does not move enough current, the bass will be weak.  The question is if 0.9A is enough (5687) or you have to go to 6BX7 (1.5A), or maybe only 2.5A will do (6AS7/6080).

 

[Oskari]

  To the best of my knowledge, only 5 companies manufactured the 5687, all American

 
Gibosi, you can add CSF to your list. I just noticed yesterday that I have a single French 5687WA from Saint-Égrève. There is always an exception, isn't there? 

 

[gibosi]

Yes, it seems that there is always at least one exception! lol 
 
And now that I know that the CSF tube exists,I will keep an eye out for one.
 
Cheers

 

[gibosi]

 
As I remember, your Sylvania 6SN7W has a metal base. Those tubes are selling for well over $100 today. whereas the 5687 Sylvania can be found today for less than a quarter of that price ( and occasionally you can find them for $8 or less).

 
I have seen three versions of the Sylvania 6SN7W, two tall bottles, one with a metal and the other with a black phenolic base, and one short bottle, with a black phenolic base. My avatar pic is the tall bottle with metal base. The metal bands have a tendency to break, but a simple twist tie is a perfectly adequate fix. lol. And because the base was broken, I got it cheap. However, I prefer the short bottle version which can often be found for around $35. But yes, the Sylvania 5687WA is very similar and even cheaper. Frankly, I am not sure I could tell them apart in a blind test....

 

[Johnnysound]

   
I don't think your IEC Mullards were actually manufactured by Mullard. Below is the genuine article. Notice the two square holes and the round hole in the plates. Also, these tubes bear etched Mullard tube codes on the side, close to the base:
 
Wd3 (Wd = EF94/6AU6, 3 = revision number)
B2K3 (manufactured in Mullard's Blackburn factory in 1962)
 
I am not sure where yours were manufactured. Rebranding was very common back in the day... Will take a look at my stash of 6AU6 and see if I can find a match.
 

 
And the Sylvania 6AH6 is very interesting. I never came across a pair of Sylvanias, only GE and Tung-Sol, and again, I wonder if yours are rebrands....

 
 

   
IEC was Mullard's US distributor. Their use of the brand was somewhat liberal to say the least, so you never know what you have – unless you do know.
 
In this case, I believe, the answer is Brimars. There is a bit of a problem interpreting 2G5 as a Philips code because 2G indicates a type which doesn't match. Brimar codes are similar enough to cause confusion. In fact, the code looks like a Brimar code in the photo. 
 
So, this time, the "made in England" is not a lie. 

 

Hi G,  I agree with you, all UK Mullards 6AU6s have the two big square holes and the characteristic round hole, just like  the Valvos made for Mullard, and also some Brimars.  Mine have a smooth plate with small rectangular holes and a big "O" getter.  I suspected rebranded american tubes , (Sylvania, Raytheon) with similar plates, but discovered that most US 6AU6 tubes have square getters (¡)
Then, Oskari is probably right, SOME (not all) 6AU6 Brimars fit, the plates are coincident with very faint vertical lines, difficult to see in the photo,  7  digit codes,  complete with the "Made in England" statement. Also,I said code 2G5||199, but it is difficult to read and it can easily be 2G5/1199, similar to the Brimars in the photo ¡¡   Now, Brimar also rebranded tubes, so the mystery continues... or not ? Maybe that "1199" means something... 
 

 
 
Here is another pair of Brimars, very similar  to the Mullards, but "foreign", obviously rebranded russian or eastern Europe tubes, just look at the "UFO" getter
 

 

[gibosi]

  Hi G,  I agree with you, all UK Mullards 6AU6s have the two big square holes and the characteristic round hole, just like  the Valvos made for Mullard, and also some Brimars.  Mine have a smooth plate with small rectangular holes and a big "O" getter.  I suspected rebranded american tubes , (Sylvania, Raytheon) with similar plates, but discovered that most US 6AU6 tubes have square getters (¡)

 
Generally speaking square getters and halo getters are primarily an indication of the date of manufacture. Tubes manufactured in the 1940's and through the 1950's tend to have square getters, be they American or European. Halo getters began to appear in the late 1950's and early 1960's. So the US 6AU6 you are seeing were likely manufactured in the 1950's. Later American tubes have halo getters. And there is one more possibility: Japanese manufacturers.
 
For example:
 
http://www.ebay.ie/itm/TWO-NOS-TOSHIBA-6AU6-EF94-VACUUM-PENTODE-AUDIO-TUBES-JAPAN-60s-FREE-SHIPPING-/181581145755?

 

[Oskari]

  Then, Oskari is probably right, SOME (not all) 6AU6 Brimars fit, the plates are coincident with very faint vertical lines, difficult to see in the photo,  7  digit codes,  complete with the "Made in England" statement. Also,I said code 2G5||199, but it is difficult to read and it can easily be 2G5/1199, similar to the Brimars in the photo ¡¡   Now, Brimar also rebranded tubes, so the mystery continues... or not ? Maybe that "1199" means something... 

 
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. 

 

  Here is another pair of Brimars, very similar  to the Mullards, but "foreign", obviously rebranded russian or eastern Europe tubes, just look at the "UFO" getter
 

 
Yes:
 

  Six 6J4Ps (Russian equivalent of the 6AU6/EF94) arrived in today's mail:
 

 

[Acapella11]

  Hi G,
 
As I remember, your Sylvania 6SN7W has a metal base. Those tubes are selling for well over $100 today. whereas the 5687 Sylvania can be found today for less than a quarter of that price ( and occasionally you can find them for $8 or less).
 
I realize more and more the importance of synergy and matching re driver tubes and power tubes. It seems that each tube will influence the other in terms of the sound. It could be that a good power tube will bring out new higher levels of performance from a good driver tube. In general I found that a good driver tube will make for a good power tube, BUT, if it does not move enough current, the bass will be weak.  The question is if 0.9A is enough (5687) or you have to go to 6BX7 (1.5A), or maybe only 2.5A will do (6AS7/6080).

 
+1 for the cheap 5687s, although I will probably start with some 6SN7s now
+1 for driver and power tube matching

 

[mordy]

Hi,
 
Today I finally got the adapters to listen to the Cg3 tubes. First impression is splendid - really great sounding tubes. Need more time to burn them in and analyze and compare to other tubes.
However, I have a problem: There is much more hum than with the other tubes I am using.
 
I am using the C3g tubes in adapters plugged into Vector adapters to clear the ring on the LD MKIII. The voltage regulator for the power tubes is grounded to the chassis of the MKIII. Any suggestion to minimize the hum?

 

[MIKELAP]

  Hi,
 
Today I finally got the adapters to listen to the Cg3 tubes. First impression is splendid - really great sounding tubes. Need more time to burn them in and analyze and compare to other tubes.
However, I have a problem: There is much more hum than with the other tubes I am using.
 
I am using the C3g tubes in adapters plugged into Vector adapters to clear the ring on the LD MKIII. The voltage regulator for the power tubes is grounded to the chassis of the MKIII. Any suggestion to minimize the hum?

Should join the club soon  hopefully tubes will come in this week will see if any hum with my adapters fingers crossed

 

[gibosi]

 
Today I finally got the adapters to listen to the Cg3 tubes. First impression is splendid - really great sounding tubes. Need more time to burn them in and analyze and compare to other tubes.
However, I have a problem: There is much more hum than with the other tubes I am using.
 
I am using the C3g tubes in adapters plugged into Vector adapters to clear the ring on the LD MKIII. The voltage regulator for the power tubes is grounded to the chassis of the MKIII. Any suggestion to minimize the hum?

 
Plugged into my LD1+ in the exact same way, C3g/adapters/Vectors, mine are as quiet as my other tubes, that is, very quiet. It might be important to note that plugged into the Vectors, the C3g's are using the LD's internal AC heaters. Is the noise worse than what you hear with a pair of 6HM5 or 6AK5? Maybe they will quiet down after more burn in..... Otherwise, those adapters would seem to be the prime suspects.....

 

[gibosi]

>> Six 6J4Ps (Russian equivalent of the 6AU6/EF94) arrived in today's mail:
 
I had forgotten all about those 6J4Ps... I got a bunch of them for a few dollars and they were all noisy. And even after burn-in, they didn't quiet down even a little....  
 
I am willing to part with these for cheap if anyone is interested. lol