For 6AS7G tube rollers here .....

  1. glitch39
    tried to put together some 6AS7G equivalents with notes (from my personal experience). of course, the usual brand/re-label disclaimers apply. So no need which one is better. The goal here is just to list the main equivalents that may work in your amp's circuit. Did I miss any equivalents?


    6080 - low gain @ 2- great vocals, wide soundstaging

    7236 - medium gain - great bass, fast and dynamic. Almost SS sounding

    5998A - medium gain in straight bottle. Plate construction like 6AS7.

    5998 - medium gain at 5, full-bodied sound, same current load as 6AS7

    421A - same as 5998 but with matched plates/sections

    6AS7G - low gain, the standard tube for most, plentiful

    6AS7GA - low gain, like the standard 6AS7G in striaght bottle

    6520 - premium 6SA7G, sometimes with 5998 plates

    6H13 - russian 6AS7G equivalent. nothing magical with these

    ECC230 - european 6AS7G equivalent. haven't seen one in person

    6528 - equiv to 5998 but very high gain at 9, twice the current load. Make sure you amp can handle it

    6336 - like 6528 but low gain at 2, still twice current load. Make sure you amp can handle it

     
  2. bdh
    Like you said at the top, this is what you experienced with you amp and input tube.

    So as far as your description of sound though, that is very dependent on the input tube (and presumably the amp as well.)

    For example with the 2c51 input, the 6AS7G's had a weird soundstage and sounded poor in my Extreme. But with the Tung Sol 5998's it was very natural and powerful.

    But with some 12AT7's the 5998's sounded way too forward and bright, but were more natural with the 6AS7G's.


    I think there is a 6080W also.
    And the 2399.
     
  3. bdh
    Oh, and I just talked with Mikhail today. He said he's developing a new adapter for the Extreme output socket so that it can handle a very different tube type -- I don't remember which tube it was though.
     
  4. sacd lover
    Quote:

    Originally Posted by bdh /img/forum/go_quote.gif
    Oh, and I just talked with Mikhail today. He said he's developing a new adapter for the Extreme output socket so that it can handle a very different tube type -- I don't remember which tube it was though.



    4X150A/ 7034/ CV2519 run VERY conservatively in the Extreme for 2.3 watts per channel.

    Heater voltage 6V
    Heater current 2.6A
    Max negative control grid voltage -250V
    Max input control grid 2W
    Max heater/cathode voltage +/-150V
    Max anode core temperature 250C
    Max anode seal temperature 200C
    Max base seal temperature 175C
    Max altitude 10,000 feet
    Min cathode heating time 30 secs

    Class AB audio
    Max anode voltage 2kV
    Max anode dissipation 250W
    Max anode input 500W
    Max anode current 250mA
    Max screen voltage 400V
    Max screen dissipation 12W




    [​IMG]


    [​IMG]

    [​IMG]
     
  5. sacd lover
    Quote:

    Originally Posted by bdh /img/forum/go_quote.gif
    Like you said at the top, this is what you experienced with you amp and input tube.

    So as far as your description of sound though, that is very dependent on the input tube (and presumably the amp as well.)

    For example with the 2c51 input, the 6AS7G's had a weird soundstage and sounded poor in my Extreme. But with the Tung Sol 5998's it was very natural and powerful.

    But with some 12AT7's the 5998's sounded way too forward and bright, but were more natural with the 6AS7G's.


    I think there is a 6080W also.
    And the 2399.




    The 6080W is about the same as the 6080 just a different manufacturing era .... there is the 6080WA /B /C.

    The 2399 is a better quality 6AS7G with tighter section matching and apparently the ability to handle higher plate current. This tube in the pic has the plates that look like the 5998 plates .... which makes sense since most 5998s were made by TS and this example is a TS 2399. This tube is possibly almost identical to some of the 6AS7s with the 5998 plates. But, I think this tube sounds the same as all my other TS 6AS7s. Personally, unless you need more gain I like the 6AS7G as well as any tube in this series.

    [​IMG]
     
  6. xenithon
    Some comments from my experience in my WA2:

    Quote:

    6080 - low gain @ 2- great vocals, wide soundstaging



    I'd love to know, but it did not fit in the amp (even though the socket is labeled 6080 [​IMG]

    Quote:

    5998A - low gain in straight bottle. Plate construction like 6AS7. nothing special.



    I got a pair of NOS GE 5998A's with the amp, and I must admit I really like them. Slightly forward vocals and not the widest soundstage, but overall a very clear/clean/crisp sound.

    Quote:

    5998 - medium gain at 5, full-bodied sound, same current load as 6AS7



    Agreed, very nice. Has some excellent low-down control and texture too.

    Quote:

    6AS7G - low gain, the standard tube for most, plentiful



    Have not tried any yet. Unfortunately Skylab has me chasing down ghosts - I am trying to find a NOS pair of GEC/Marconi brown-based tubes to pop my 6AS7G cherry [​IMG]

    I second the comment that it also depends a lot on the other tubes in the complement. I found that rolling the 6922/6DJ8 preamp tube yielded a more significant impact.
     
  7. glitch39
    you mean a brown base 6as7g like this?

    [​IMG]
     
    RodneyMarion likes this.
  8. scootermafia
    Quote:

    Originally Posted by sacd lover /img/forum/go_quote.gif
    4X150A/ 7034/ CV2519 run VERY conservatively in the Extreme for 2.3 watts per channel.

    Heater voltage 6V
    Heater current 2.6A
    Max negative control grid voltage -250V
    Max input control grid 2W
    Max heater/cathode voltage +/-150V
    Max anode core temperature 250C
    Max anode seal temperature 200C
    Max base seal temperature 175C
    Max altitude 10,000 feet
    Min cathode heating time 30 secs

    Class AB audio
    Max anode voltage 2kV
    Max anode dissipation 250W
    Max anode input 500W
    Max anode current 250mA
    Max screen voltage 400V
    Max screen dissipation 12W




    [​IMG]

    [​IMG]


    [​IMG]

    [​IMG]




    OH GOD WHAT IS IT
     
  9. Maxvla Contributor
    Ha that thing looks like a commercial jet engine.
     
  10. Skylab Contributor
    Quote:

    Originally Posted by sacd lover /img/forum/go_quote.gif
    Personally, unless you need more gain I like the 6AS7G as well as any tube in this series.



    I agree with this. I do think the Tung-Sol 6AS7G's sound a little better than the RCA's, and I think the GEC brown-base UK ones sound a little better still, but I don't think the differences are so huge that they are worth dealing with unless you are a psychotic tube collector...like me [​IMG]

    Quote:

    Originally Posted by xenithon /img/forum/go_quote.gif
    Unfortunately Skylab has me chasing down ghosts - I am trying to find a NOS pair of GEC/Marconi brown-based tubes to pop my 6AS7G cherry [​IMG]




    HA! And yeah, this is my favorite of all of these tube types, no doubt.

    Quote:

    Originally Posted by glitch39 /img/forum/go_quote.gif
    you mean a brown base 6as7g like this?

    [​IMG]




    YEP - that is the one. Has a slightly different plate structure than your typical US made 6AS7G.

    To the OP: There is also the 6AS7GA, and 6AS7GYB. The GA is a straight-bottle 6AS7G, with black base; the GYB has a brown base. AFAIK, both were only made by GE.
     
  11. xenithon
    Skylab - should you ever come across any NOS pairs of those I beg of you to alert me [​IMG] . I've been looking out for a few months now; there is one on eBay but only one (need a pair) and the seller hasn't got any others [​IMG]
     
  12. Skylab Contributor
    There was a guy in the UK selling a whole bunch of these NOS for a while - but he must have sold out, since he doesn't seem to offer them now, although he has lots of other tubes for sale still. Yes, I will let you know if I see more of them for sale.
     
  13. Gvvt
    scootermafia,

    it looks to me like a space heater. One will take care of a small room - two for larger spaces (above 850 sq. feet). Order now, and you can get a hand-made Amish wooden mantel / case.
     
  14. PaulyT
    I read somewhere (google search) that all 5998 tubes are made by Tung-Sol, even if branded differently. Can anyone verify this? These are hard to find for sale... anyone know of a good source?
     
  15. Skylab Contributor
    It's true. Only Tung-Sol made the 5998. You see them branded Chatham (which was bought by Tung-Sol), and IBM, and of course the most famous branding was the Western Electric 421a, but even these are 100% identical to the Tung-Sol 5998.

    GE did make a "5998A", but this is a different tube. It has a plate structure more like a 6AS7 than the 5998, and is in a straight-bottle. They also sound nowhere near as good as the TS 5998.
     
    3083joe likes this.

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