Dismiss Notice

Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

Ampeg SVTDI

Discussion in 'Effects [BG]' started by zaten, Mar 20, 2006.


  1. zaten

    zaten

    Mar 20, 2006
    Dubai - UAE
    Hello from Beirut! I'm new to this forum and happy to be here :)


    I bought an Ampeg SVTDI last week and would like to know what you guys think of it for those who've tried it. The box is still very recent from Ampeg so there's very little literature on it online.

    I've always wanted a tube sound but with my modest gigging experience I didn't want to invest a whole lot of $$$ into a tube head and cabinet.

    For 400$ (100$ more than in US), the box did warm up my sound (and looks fantastic to boot!): highs are crisper and richer and lows are fuller and sweeter. Overall, a very pleasing tone enhancement for the already sweet-sounding ba115 combo. I only wish it had a gain knob to dial in different tube levels.

    Has anybody tried it yet?



    zaten
     
  2. Joe P

    Joe P

    Jul 15, 2004
    Milwaukee, WI
    Welcome, Zaten!

    ~~~~~~~~~~~~
    This question is based on some things I read on Glenn's linked thread, but... Maybe an audio engineer could help with this one: I keep hearing it said that if you drive a tube stage harder, you get more tube-y tone, but this only counts if you're driving into saturation, right?

    If we're talking about the harmonics generated by a tube's natural nonliear amplification characteristics (assuming it's not running with much linearizing negative-feedback, of course), then at any gain outside of saturation, it shouldn't matter how much of the total gain is the nonlinear tube, and how much is other perfectly-linear (solid-state, or whatever) stages, because gains multiply - not add. Does this make sense?

    Unless you're looking for clipping ('soft' or otherwise), it should give you the same harmonic enhancement at whatever level you drive it at (signal-to-noise would be another matter, of course).

    Mark R.: where are you?..

    Joe
     
  3. zaten

    zaten

    Mar 20, 2006
    Dubai - UAE
    Thanks for the welcome, Joe P.

    To answer the previous thread, I think you can get decent tube coloration with the SVTDI. Even with one 12AX7, there's noticeable "tube" improvement for your tone. Other combo brands already have a 12AX7 at the input and Ampeg will soon include one in their all combos. Makes you wonder what made them wait so damn long!
    Anyway, I'm glad I have it as a separate box and not as built-in preamp. This was I can use it with any other amp. I wonder how the SVTDI compares to other 12X7 DIs, though...



    zaten
     
  4. Joe P

    Joe P

    Jul 15, 2004
    Milwaukee, WI
    Well now I've read how some of these "tube" pres are running super-low plate voltages on the tubes - I mean running them way-WAY outside of their designed parameters! (it gets a little expensive dealing with voltages in the hundreds, I guess...) - I'm pretty-sure that at least the Ampeg is running a reasonable voltages and-all!

    I also wonder about amps or pres that run 'global feedback' in their circuits; as far as I understand, this g-feedback 'covers a multitude of sins', design- and component-wise, but really messes with any kind of 'natural' tube response!

    I was playing with an SWR amp at a music store. I know SWR is supposed to be good stuff, but when I over-drove the input, I got this tremendous, violent, crackle!! I'm thinking 'how can this be? That's in no-way tube clipping that I'm hearing!" In fact - is was so violent and ubrupt that I'm thinking it sounds like they're using global feedback. ...Either that, or the tube isn't the first stage in the circuit - well that would suck.

    Anyway: I guess what I'm saying is that it seems all you have to do is have a tube anywhere near a circuit, and call it a "tube amp"! ..like waving a chicken over the kettle, and calling it 'chicken soup'. I imagine that with the Ampeg, at least no one's messing with you; it's a true tube pre!

    I'd still like to hear a report from someone who ran a booster before it, and can confirm that it achieves natural wave compression to soft-clipping to decent-sounding hard-clipping - like a tube-pre SHOULD. I think if there's much negative circuit feedback at all, the clipping gets very harsh and ubrupt.

    Joe