For 6AS7G tube rollers here .....
Aug 25, 2016 at 7:36 PM Post #3,766 of 9,502

Ey1G9s6uIgjYn3O2zi_ebYW3e6VRbIiCEgsLiwwbjkZ2oGaLJEr0ghqP_FpqIRpg8jCeMxjS=w255-h184-nc
 
Oct 17, 2016 at 1:37 AM Post #3,767 of 9,502
Hello does anybody here have a pair of GEC 6AS7G (brown base) tubes I can buy off you? I understand these are highly coveted and rare tubes, but thought it's worth a try. I have extra money so please PM me if so. Otherwise please let me know where I can buy a good pair.
 
Also would anybody please tell me if they have compared both the GEC 6AS7G to the GEC 6080's? (brown base ST tubes vs. the straight form tubes?) I'm very interested to know what the sonic differences are between the two. Perhaps @gibosi would know...
 
Additionally I would be interested to know which are considered the best 5998 tubes? I saw a conversation about these earlier on this thread, but didn't notice which brand was the regarded as best.
 
This is for my Elise tube amp which accepts both 6AS7, 5998 and 6080 as power tubes, and 6SN7 class as drivers
 
Oct 18, 2016 at 10:44 PM Post #3,769 of 9,502
  Hello does anybody here have a pair of GEC 6AS7G (brown base) tubes I can buy off you? I understand these are highly coveted and rare tubes, but thought it's worth a try. I have extra money so please PM me if so. Otherwise please let me know where I can buy a good pair.
 
Also would anybody please tell me if they have compared both the GEC 6AS7G to the GEC 6080's? (brown base ST tubes vs. the straight form tubes?) I'm very interested to know what the sonic differences are between the two. Perhaps @gibosi would know...
 
Additionally I would be interested to know which are considered the best 5998 tubes? I saw a conversation about these earlier on this thread, but didn't notice which brand was the regarded as best.
 
This is for my Elise tube amp which accepts both 6AS7, 5998 and 6080 as power tubes, and 6SN7 class as drivers


You may want to go to the following page and post a want to buy post:
 
http://www.head-fi.org/f/6553/cables-speakers-tweaks-accessories-for-sale-trade
 
Good luck!
 
Oct 19, 2016 at 1:36 AM Post #3,770 of 9,502
  Oh yes also I'm interested to find a pair of tubes in the 6SN7 or small 6DJ8 class that are dark meaning with less treble and more bass, if anyone can recommend which ones? Thanks so much!


I am answering in public for the edification of those who may be interested I am not selling.  When you say dark in a 6DJ8 my answer went to the English tubes .  This time however you don't have to search all over the "Tubi-verse"  in order to find a good pair of NOS Mullards etc. ( I don't think actual NOS tubes are sold anymore with exceptions of course.)  The small Gold Lion current production from New Sensor tubes have that darker sound.  They make a 6922 with gold pins and a steel pin version at least they did  for a while.
 Your options for a dark sounding 6SN7s are limited, part to what one  calls dark sounding.   If you want bass you know what everybody will tell you- Ken Rad(KR).  What is even better is they come in a black glass version, which seems to be a pre requisite, for many of you guys. You can track down some Philips tubes, usually in the form of Pope's branded 6SN7s.  They will be expensive and a really good NOS pair not so  easy to find.  OTOH it may be easy if you can cajole Upscale audio to sell you a pair.  
You can save a fortune if you like the sound of Sylvania 6SN7 GTBs which many consider mellow.  The problem is that they are readily accessible and have ordinary aesthetics.  They do come in a couple of flavors.  I mentioned some time ago that the Green letter on black base GTBs sounded best in my memory, and then couldn't find any in my collection.  I withdrew the green letter statement, but have subsequently unearthed a few pairs, so I am reasserting it.
How about ECC 32s for $600/Pair (NOS NIB), no I am not selling just telling what they can cost.
Finally if it's bass you want get HPs that deliver oodles of bass, get cables tuned to bass, use the KRs.  Tune your entire system to deliver bass.  I am going to have to make an HP subwoofer LOL.  Best of Luck 
 
Oct 29, 2016 at 4:16 PM Post #3,771 of 9,502
I posted about these tubes awhile ago a few people seemed to think they looked physically similar and that they should sound close enough to use together...put them away for awhile as i got a few different sets of power tubes for my WA2...now that i took them back out thinking about giving them a try again i noticed that the one has what appears to be a bottom getter that the other one doesnt....on top of that it is a clear top black plate. Just curious if anyone really familiar with RCA 6as7g's might be able to shed a little more light as to what might be the difference in these and if they could have different sonic traits. From the small amount of time i spent listening to them a few months ago i thought they sounded fine together but the amp was brand spankin' new to me then.
 

 

 

 
 
**EDIT**
 
Just found this from a HF Thread 
http://www.head-fi.org/t/324469/review-four-6as7g-based-home-tube-headphone-amps-reviewed-and-compared#post_4194061
 
"RCA also made “Grey Plate” and “Black Plate” versions – all other makers 6AS7G’s have black plates. Supposedly the Black plates sound better, but I believe this is either untrue or extremely subtle at best. Some also have an additional metal “skirting” shielding the wiring as it travels from the base to the grid, but I have not been able to attribute any real sonic differences there either."
 
Oct 29, 2016 at 5:11 PM Post #3,772 of 9,502
The tube with orange paint was manufactured in 1961 and the tube with white paint was manufactured in 1956, some 5 years apart. Due to such things as the introduction of new materials and techniques, new research and feed-back from the field, changes were made in the design and construction of the RCA 6AS7G during that 5 year period. Whether these changes resulted in a difference in sound, there is no way to know simply through a visual inspection. This can only be determined by someone such as yourself actually comparing them.
 
Nov 2, 2016 at 7:35 AM Post #3,773 of 9,502
Wondering

Are gec6as7g the same as a1834 and the same as cv2523?

Is there much veriation between years ot can a matching pair be easily plucked from two various years?


Is the z crucial on tbe bottom right of the box? What does the z, the 4 or x/z mean?

Thanks in advance for any help
 
Nov 2, 2016 at 10:36 AM Post #3,774 of 9,502
Wondering

Are gec6as7g the same as a1834 and the same as cv2523?

Is there much veriation between years ot can a matching pair be easily plucked from two various years?


Is the z crucial on tbe bottom right of the box? What does the z, the 4 or x/z mean?

Thanks in advance for any help

 
Yes, these are all the same tube:
 
http://www.radiomuseum.org/tubes/tube_a1834.html
 
In general, it is best to have tubes that were manufactured at about the same time. That said, I have three pairs, 1949, 1956 and 1961, and my old ears can't reliably tell the difference between them.
 
In the case of British tubes, the letter "Z" is a "manufacturer's factory identification code" which tells us which company manufactured the tube and in which factory:
 
Z = MO Valve Company, Hammersmith
 
"X" = When approval has been given for the use of a valve in MDAP equipment by the Director of Electronics Research and Development (Air) but that valve has not received qualification approval the letter X is used.
 
As to the number "4", I have yet to discover what it means, but this number is commonly found on GEC/MO Valve tubes.
 
On the other hand, not all GEC 6AS7G have these CV codes. And in some cases, all the silk-screened text may be gone. But even so, the construction of a GEC 6AS7G is different than any other 6AS7G, so they are easy to recognize.
 
http://www.tubecollector.org/cv-valves.htm
 
Nov 2, 2016 at 10:46 AM Post #3,775 of 9,502
Yes, these are all the same tube:

http://www.radiomuseum.org/tubes/tube_a1834.html

In general, it is best to have tubes that were manufactured at about the same time. That said, I have three pairs, 1949, 1956 and 1961, and my old ears can't reliably tell the difference between them.

In the case of British tubes, the letter "Z" is a "manufacturer's factory identification code" which tells us which company manufactured the tube and in which factory:

Z = MO Valve Company, Hammersmith

"X" = When approval has been given for the use of a valve in MDAP equipment by the Director of Electronics Research and Development (Air) but that valve has not received qualification approval the letter X is used.

As to the number "4", I have yet to discover what it means, but this number is commonly found on GEC/MO Valve tubes.

On the other hand, not all GEC 6AS7G have these CV codes. And in some cases, all the silk-screened text may be gone. But even so, the construction of a GEC 6AS7G is different than any other 6AS7G, so they are easy to recognize.

http://www.tubecollector.org/cv-valves.htm
And i believe the first of two letters gives the year bus is that just for the 50's and 60's?

When do you think production may have stopped?

Ps i'll read your second link - it looks great
 
Nov 2, 2016 at 1:39 PM Post #3,776 of 9,502
And i believe the first of two letters gives the year bus is that just for the 50's and 60's?

When do you think production may have stopped?

Ps i'll read your second link - it looks great

 
As per the second link, a two-letter date code was used until the mid-to-late 1960s (ZM = 1968, December), and after that, a 4-digit numerical code, similar to that used in the US, was used.
 
So, for example, my three pair:
 
1949 = EM
1956 = MC
1961 = SB
 
According to Wikipedia, GEC/M-OV ceased the manufacture of vacuum tubes at the Hammersmith location in 1988. However, I have no idea if they continued to produce the 6AS7 into the 1980s. Perhaps others who have this tube would be willing to take at look at the date codes and let us know if theirs were manufactured in the 1970s or even later.
 
Nov 2, 2016 at 3:54 PM Post #3,777 of 9,502
As per the second link, a two-letter date code was used until the mid-to-late 1960s (ZM = 1968, December), and after that, a 4-digit numerical code, similar to that used in the US, was used.

So, for example, my three pair:

1949 = EM
1956 = MC
1961 = SB

According to Wikipedia, GEC/M-OV ceased the manufacture of vacuum tubes at the Hammersmith location in 1988. However, I have no idea if they continued to produce the 6AS7 into the 1980s. Perhaps others who have this tube would be willing to take at look at the date codes and let us know if theirs were manufactured in the 1970s or even later.
I have one tube with codes on it of 6935 so i guess thats 1969

Im being offered a tube with no codes on it so im guessing they've been rubbed off.

I also have bought two in the past with nothing on it. They sound legit. Im guessing they started with codes on them?????
 
Nov 2, 2016 at 6:28 PM Post #3,778 of 9,502
I have one tube with codes on it of 6935 so i guess thats 1969

Im being offered a tube with no codes on it so im guessing they've been rubbed off.

I also have bought two in the past with nothing on it. They sound legit. Im guessing they started with codes on them?????

 
Yep, 69 = 1969 and 35 = week 35.
 
I think there are two reasons that some GEC 6AS7G have no date codes. In many cases, as you surmise, the codes have rubbed off over time. And in some cases, the tubes were placed into the civilian market rather than sold to the British military. Typically the text and graphics painted on consumer tubes do not include date codes. And I should add, a GEC CV2523 is identical to a GEC 6AS7G. The only difference is the paint on the bottle. The tubes themselves are all the same. That said, I haven't seen all that many civilian GEC 6AS7G, but they are out there.
 
Nov 2, 2016 at 6:41 PM Post #3,779 of 9,502
A couple weeks ago i found this single GEC 6080WA /CV8614 .I am looking out for another one to make a pair is it important to get the same 6080WA/CV8614 markings  or another 6080WA lets say for example GEC6080WA/CV2984  would be ok                                                                                        
 
Nov 2, 2016 at 8:55 PM Post #3,780 of 9,502
  A couple weeks ago i found this single GEC 6080WA /CV8614 .I am looking out for another one to make a pair is it important to get the same 6080WA/CV8614 markings  or another 6080WA lets say for example GEC6080WA/CV2984  would be ok                                                                                        

 
It appears that CV2984, CV5008 and CV8614 all refer to the 6080. I do not know why there are three separate CV numbers for this tube. And I have a pair labeled as a 6080WA (date code SL = 1961). And as near as I can tell, no matter how they are labeled, they are all the same tube.
 
I would suggest that you assume these are in fact all the same tube and instead concentrate on the year of manufacture. The tube pictured above, with a date code of YF, was manufactured in June, 1967. And therefore, if you can find another one manufactured at about the same time, in my opinion, that would be a suitable mate.
 

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