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How much of sound do tubes account for?

Discussion in 'Amps and Cabs [BG]' started by chaosMK, Oct 24, 2005.


  1. chaosMK

    chaosMK

    May 26, 2005
    Albuquerque, NM
    Hi-fi into an old tube amp
    In an amp/cabinet setup, how much of the tonal output do you guys think the actual tubes (as in brand/type of tubes) account for? Do the tubes have a huge influence on your sound, or is it more the electronics in an amp/pre?
     
  2. It depends ENTIRELY on what amp you're using. Your question is too broad for one definite answer.
     
  3. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    If you're amp's a hybrid amp, then the tube will account for some warmth, but it's not affecting everything.

    In a full tube amp, at low volumes, the preamp is the only thing that's really affecting the sound. It's not 'til you get them power tubes cookin' that they really start affecting the sound (and oh, what a sound it is!).

    This however, is a very broad answer, and varies from amp to amp, like PBG says.
     
  4. chaosMK

    chaosMK

    May 26, 2005
    Albuquerque, NM
    Hi-fi into an old tube amp
    If you are using an all tube amp like a Mesa/Boogie Bass 400/400+ or SVT-II/CL, or V8, etc.

    If it varies greatly from amp to amp, which amps does it vary the most or least with?
     
  5. Trevorus

    Trevorus

    Oct 18, 2002
    Urbana, IL
    Also a very broad question. I'd say that there is quite a bit of difference in using different types of tubes. A 12ax7 and a 12at7 can sound very different even being manufactured by the same company. The reason being the different gain structure. But as far as different brands, they all have a little bit different design inside. Some have bigger plates, and more windings on the screen, which can make a massive amount of change in the sound. In most amplifiers, if you change one thing, it ends up affecting everything else at least somewhat.
     
  6. Tom Bowlus did a very nice review of the impact of various tubes in various preamps.... the results were interesting, with some preamps being much more impacted by different tubes than others, etc.

    Maybe Tom will provide a link to the thread (I think the review is on his BLOG also). Otherwise, PM him and he'll give you his take on this.
     
  7. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Here is the link to the one thread. I also did a comparison of tubes in my Walkabout some time ago, and this is on my blog. I am working on some additional tube reviews, and will try to get them up as time allows.

    One bit of advice, though: just listen to whatever Psycho Bass Guy has to say! :D

    Take care, Tom.
     
  8. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    Bought a THD univalve to experiment with a tube amp. It's designed for swapping out tubes and the difference can be minimal or major depening on the combination and other settings use on the amp.

    The same model/make tube by the same manufacuturer can vary in output when it's new and the tone will vary as the tube wears. So there's amazing array of tone variations available from changing tubes - at least through the THD (both pre and power).
     
  9. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Interesting. How does the Univavle sound as a bass amp?

    Tom.
     
  10. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Plenty of bass on the clean/lo-gain channel but of course the output is lacking. You can hear it with no problem and even practice to tunes at mild volume but you're not going to play with anything much beyond an unmic'd acoustic guitar. That can be stepped up some running a pre into it - but not significantly.

    Through the hi-gain channel the output is serious and would easily work with an unmic'd drummer - but the low end is lacking for a lot of tunes. It has a noise reduction switch that picks up the low end some but it also cuts the brightness on the top half and usually is not worth the trade off for most tunes.

    I bought the THD for experimentation with a micro setup and I've built an experimental cab I can adjust the cab volume on and swap different speakers for trials. I've got a pioneer audio speaker in it currently (about 40hz - 6kHz in my recall). I've ran the THD into that and mic'd it through an audix F12 > Art MP mic pre > QSC 1450 > Aguilar GS-112 and L'acoustics 15." Pretty sweet and plenty of volume. In place of the QSC I've been planning to use a clarus (or two) for the micro setup and perhaps the GS-112 permanent for output. Will see.

    I contacted THD before buying the amp and they said it would handle the bass frequencies. Some guitar amps will, some won't. I didn't ask for details on that but I will just to know next time I call them (on the belated side for sure). But, becuase of output, they thought I was nuts when I told them I wanted it for bass.

    With all the frigging gadgets the amp has on it, I couldn't imagine having made a better choice for being ignorant about amps. I've literally found some application for all of them. I really just wanted something low output that would take about any tube without rebiasing.

    Probably the main suprise and drawback has been how useless the treble control is. Although I suppose, given it's a guitar amp, that shouldn't be too astounding. It's not that it doesn't treble up, it just dulls tone in the process. Cutting bass has a similar but less pronounced affect but I like a full bottom and clarity so cutting bass usually is not an option. I nearly always have bass maxed and treble completely cut and adjust through other amp controls which produce results more to my liking. I've used the "attitude" control much more than the treble. Don't know exactly what it does technically but so far it's had a brightening, compression, presence/woodieness affect in application.

    I've run an MXR M80 or a Sans DI into it if I needed tone control. That has rarely been necessary becuase all the switching (noise reduction; loV/hiV; full power/attenuator) and the lo and hi gain channels typically suffice.

    Not hard to keep it clean depending on the tubes and settings. Haven't made a conscious effort to explore it but I really haven't found any distortion out of it that I find appealing in just playing through it so far. Had it about a month.
     
  11. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    actually, the comment about the hi-gain not having the low end needs some updating. Like I said, haven't had it long.

    I really haven't used the hi-gain much, primarily if tone was too dark on the lo-gain channel. In general, I want solid bottom but I also like clarity and a lively mid and top half unless it's not the tone for the tune. I've actually used the hi-gain channel more in the last week than the rest of the time I've had the amp.

    The pup/tube combination accounts for a major portion of the frequencies the amp reflects. Simply changing one of the pre tubes the same pup on the hi-gain channel can go from a darkness, comparatively like I would experience on the lo-gain channel, to a nice full balanced spectrum, to too bright with noticeable distortion. It can be as dramatic as changing pups. Of course if the pup is thin on top (whatever) tone will be reflective but a tube can noticeably minimize the effect, accentuate it, or compensate to a limited degree.