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Replace AKG Solitube's tube with something better.

Discussion in 'Pro Audio Equipment' started by Borrachon, Oct 13, 2005.

  1. Borrachon

    Borrachon Guest

    After reading great things about it in just about all music forums, I bought a second hand AKG Solidtube and...I don't like it at all.
    I thought maybe if I replace the tube with something more "High Standart" it will sound better.
    Ever heard of somebody doing that?
  2. Markd102

    Markd102 Well-Known Member

    Apr 24, 2001
    hehe, welcome to the club ;)

    You can try another tube. 12AX7's are easy to get.
  3. RemyRAD

    RemyRAD Guest

    Sep 26, 2005
    You know, this microphone is going to sound much mellower than any transistor microphone. Almost mushy. That's probably why you don't like it. Don't get rid of it! My vintage U67 sounds mushier than my U87. The 67 does not use a 12AX7 which is a dual triod but rather it uses an EF86, which is a pentode, it produces more noise than a 12AX7. The next time you record a female vocalist, put her on this microphone. A much easier way to get girls. They will love you for it and you will love the microphone. A. friend of mine, a truly fabulous engineer with gold record credits etc., had a U87, transistor removed, modified to a 12AX7. He likes it and all that but he keeps asking me to loan him my U67 it is even more mushy than is modified one. You didn't make a mistake by purchasing that microphone.
  4. Borrachon

    Borrachon Guest


    I'm very familliar with the U67, I've recorded a whole album with it...I love it.
    Now...I don't get the comparaison to the Solidtube, you really think it's that good?
    I also own a U87 wich I'm not too crazy about neither, even though it's really a Neumann and can be great...sometimes.
    I'd love to get a C12V but it's really expensive.
  5. kidvybes

    kidvybes Guest

    Try a different tube...

    ...I would recommend swapping the tube for a GE black plate 6072/6072A...the 12AX7 is known for it's high gain, but the 6072 (high grade 12AY7) has a cleaner, clearer sonic character with a bit lower gain...the 6072 is used in many of the classic tube mics...there's no problem in subbing the 12AY7 for a 12AX7, just a slight loss of gain (which may assist in giving the mic more clarity)...the 6072 is simply an audiophile (low noise) version of the 12AY7...I have replaced the tubes in my own mic collection (that came with 12AT7/12AX7) to 6072s with excellent results...
    ...check here for a good example of this tube:
  6. Borrachon

    Borrachon Guest

    OK...much thanx, that looks like good advice.
    Clarity is what I miss in the Solidtube and i got enough gain anyway.
  7. TornadoTed

    TornadoTed Guest

    How the heck do you take the SolidTube apart to replace the tube? The bottom only appears to have the connecter and the top grill wont budge however hard I twist it!
  8. cheekyb

    cheekyb Guest

    there's three screws on the base on the actual barrel - not the two on the connecter. Then it comes apart.

    The cage comes of with a left twist and interestingly the cage is lined with foam. Now this in itself maybe the reason the mic sounds a little dark? I might give it a try.!
  9. RemyRAD

    RemyRAD Guest

    Sep 26, 2005
    What's one man's garbage is another man's treasure! I traded off one of my two AKG 414BULS for a U67. He thought it was too mushy. I win! Besides, it will keep my other one company.
  10. TornadoTed

    TornadoTed Guest

    Apologies in advance for hijacking the topic but it's kinda relevant !!

    My 2 TL Audio C1 compressors use two 12AX7 valves per channel, what would happen if I replaced them with 6072 valves? Would this work, sound any better, what are the possible pit falls?

    As you may guess I don't know much about electronics so any knowledge would be really helpful.

    This is info from the TL Audio web site about the C1:

    The C-1 features a low noise solid state preamp followed by two valve stages per channel. The valves are General Electric ECC83/12AX7A types, run from a stabilised 250v DC power supply. The first valve stage acts as a voltage amplifier, with the second stage forming part of the gain control element.

    Incedently this is info about the new version of the C1, I have the old version with different valves I would guess. Would it help to put General Electric ECC83/12AX7A valves in my C1's?
  11. TornadoTed

    TornadoTed Guest

    Could you damage the capsule of the SolidTube by removing the foam, if used carefully with a pop shield?

    I would be interested to know this and how much difference it would make to the sound as I've always thought it sounds a little bit 'dull' I wouldn't want to damage it though.
  12. cheekyb

    cheekyb Guest

    I tried it and I think I was pretty careful in using the same sound source at the same distance from the speaker, I couldn't hear much of a difference so I used Logic's match EQ to SEE the difference. Even then it was pretty subtle, a tiny bit more upper frequency - and I mean tiny and surprisingly a tiny bit more bottom end too, again not enough to warrant the exercise.
    I've a feeling the foam is part of the dampening mechanism for the capsule so I'm going to put it back in.

    I've got one of the above mentioned tubes on order and I'm hoping that does do a bit, I'll let you know when I try it out.
  13. TornadoTed

    TornadoTed Guest

    Cheers cheekyb. I've got a bit of a yellow streak when it comes to modifying equipment :lol: I just don't trust me skills enough.
  14. Groff

    Groff Active Member

    Jul 18, 2004
    Does anyone try with NOS tubes?
  15. Borrachon

    Borrachon Guest


    Hi everybody..thanx for trying to help lol.
    After a few weeks of using this thing i found that it actually sounds very nice with some people, mostly female singers.I'm keeping it, it can be terrible but it really has something to it worth keeping.I paid 300€ for it and i'm glad i did.
  16. veatch

    veatch Active Member

    Feb 16, 2004
    I use mine mostly on female singers as well. I used it on a couple of male singers, one of which had a fairly nasely tone to his voice. Worked well, especially in the mix, which is what counts, right? :)

    Opinions vary, trust your own ears...
  17. cheekyb

    cheekyb Guest

    Well, I tried a new and recommended - tube a GE 6072A from the US. It was manufactured in 1966 :shock:

    To cut a long story short - the results were pretty disappointing. The 'slight' loss of gain was 4.2 dB which was a little more than I anticipated. But when I level matched the before and after I couldn't hear a difference. So, out with the logic match eq and there is virtually no difference - its a flat line up to 1100Hz then a tiny dip, a tiny bump at 2-3KHz, a tiny dip at 5.4 Khz and then a more pronounced hump between 17 and 20KHz but still miniscule.

    So now I have a quieter microphone that may sound a little different to someone with bat ears!!

    One last test I will do is record with the gain on the pre boosted - MH ULN-2 in this case - to see what happens. Although that might just record a difference in the pre's performance.

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