SWR Grand Prix thin sounding

Discussion in 'Amps and Cabs [BG]' started by wneff, Oct 21, 2003.

  1. wneff


    May 27, 2003
    Woburn, MA
    I have a question for all owners of an SWR Grand Prix pre-amp:

    If you put your pre-amp in flat, (all pots center position, Enhance center position), is it flat?

    I perceive my Grand Prox as very thin sounding and need to cut LOTS of teble (almost to 0), boost bass (3 o'clost), cut migh mids at 1 kHz (9 oclock) to get an acceptable sound.

    On my Gallien MB200 I put my bass at 1 or 2, low-mid at center, high mid at 11 oclock and treble at center and it still sonds fuller and warmer. (The SWR then gets boomy)
    I tried different tubes, that helped somewhat.
    I'm still not happy with the sound.
    From the concept I think its the perfect amp for me, but I just don't seem to get a good sound out of it.

    I observe this through the headphone out, but also through the power out.

    Again, when you set your grand prix to flat, is it flat or do you need to tweek to get it flat?

  2. IMO, the SWR preamps are relatively flat (except for the Aural Enhance feature) with just a breath of tube warmth (I recommend the EH12AX7 to smooth out the highs). What you hear as "flat" from your GK is a result of "voicing" to make bass guitars sound better. To get the same sound with your SWR you'll have to use the EQ. Try just a little at a time. If you want a fatter bottom without the boominess, try boosting low mids (160-240).

    Now about that AE knob. For a "fuller" sound, turn the Aural Enhance knob all the way off (counter clockwise), or at most to the 8 or 9 o'clock position (if you want the additional warmth from the tube, it uses the second side of the 12AX7). Up to the 12 o'clock position it has a sawtooth EQ effect, past 12 it starts scooping the mids.

    If no amount of playing with the EQ gets you the sound you want, hey, it may not be the preamp for you (or the pre may be defective in some way). Check the sound samples (and EQ settings) on http://basstasters.com/preamps/swrgp.htm to check if you are getting something that is close to that sound.
  3. I recently purchased a Grand Prix to use as a back up / rehearsal rig.

    I run the EQ entirely flat (with the exception of the low cut filter pulled out). I percieve the sound as flat....BUT

    The other factors clearly have a HUGE factor on the sound. The most obvious one is the speaker cabs. Change the cabs and the entire voicing of any amp / pre amp will need to change to go back to the sound you want. Even headphones clearly have big variations in sound.

    I listened to all of the Pre amps on the The Bass tassters link..but came to only one conclusion..As I was listening to the Pre amps through my crappy PC speakers and most importantly, not played with my bass, with my string guage, with my fingers...it all became a bit immaterial...

    I already own and gig with an SWR SM900 and love the sound..so thats what prompted the choice of the Grand Prix..and is why I percieve mine as sounding flat.

    Joe is bang on in that you are comparing the SWR to the GK...they will sound different..

    Its all in the ears....

    Hope this helps

  4. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    It's voiced pretty flat IMO - I run it with the EQ flat and aural enhancer at 10 o'clock and it add a bit more bass thickness, growlier low-mids, wetter mids, and subtly enhanced highs compared to my bass's direct DI'd sound.

  5. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    South Shore MA

    I find that SWR gear works for me but because thay are voiced flat, they require tweaking to get a more "traditional" amp tone out of them.

    On my old SM400 I felt I was starting to lose some of the depth in tone it used to have. I changed out the tube (I ended up with a Groove Tubes ECC83, which sounded best to my ears) and replaced all the opamps in the preamp (there are 9 in the SM400 pre, they cost $.47 each at www.mouser.com). The result was the return of the big tone I was getting although someone pointed out to me it could have been the result of simply cleaning some contacts. Whatever, it worked, I believe in voodoo.

    As Joe_Atlanta pointed out it simply may not be the pre for you. You may like the concept and feature set but if the sound isn't there for you, you may want to save your time and aggravation and look at other things.
  6. vanselus


    Sep 20, 2000
    Boulder, CO
    It could be technique and fingers here too...

    check out the GP clips at www.basstasters.com

    are they thin sounding?
  7. Steve


    Aug 10, 2001
    I've scoped my Grand Prix with pink noise. Flat is flat with AE at zero.
  8. 'Why yes, I am a professional musician. Would you like fries with that?':D
    LOVE IT !!
  9. I did the same thing, played through a pair of JBL floor standing speakers and 60w Yamaha power amp: all the preamps sounded the same to me.

    Many people mention the SWR GP and IOD being "thin" sounding. I run mine flat also, no aural enhancement, no drive.
  10. Bikertrash has hit the nail on the head in my opinion...checking the unit with pink noise has shown that the unit gives an uncoloured sound of the bass when the EQ is flat.

    So the sound you are hearing is the sound of the Bass you are playing.

    I personally love hearing my bass as it is and being able to dial in or out EQ to suit.

    But that is not everyones taste...

  11. wneff


    May 27, 2003
    Woburn, MA
    Here is the test I made:

    a) Bass -> GK200 adjust EQ until it sounds good

    b) Bass -> Grand Prix -> GK200 (Grand Prix in "flat", adjust so volume until a and b are same.

    If my Grand Prix was linear, a) and b) would sound essentially the same, maybe b) would be warmer due to the tube. But I have to significantly increase Bass and lower treble to get the same sound.

    What do you guys think?

    I'm impressed with the pink noise test - very professional. I'm living close to Niagara Falls, maybe I can sample the waterfall and send it to the system with and without the Grand Prix and hear if it sounds different? :)

    Also, does the Grand Prox sound essentially the same as the other SWRs? If yes I'll take it to the music store and check if mine has a problem.

    What do you think?

    BTW, if anyone wants the pink noise of Niagara Falls let me know.
  12. Steve


    Aug 10, 2001
    b) Bass -> Grand Prix -> GK200 (Grand Prix in "flat", adjust so volume until a and b are same.

    What do you guys think?

    I think if you run the output of one preamp into the input of another preamp, you will run into impedence mismatch issues that could generate all maner of strangeness tone wise
  13. KB


    Jan 13, 2000
    Chapel Hill, NC
    Definately try a different pre-amp tube. I have found that pre-amp tubes have a dramatic effect in SWR gear. My experiences with types of tubes in my SM500:

    EHX EH12AX7 - growly tone, slightly compressed, not overly warm

    Ei 12AX7 - warm kind of a V shaped EQ

    Jan-Philips 12AX7WA - more tubey sounding, warmer, but almost slower feeling (the one I currently have in my SWR). Wide EQ

    Sovtek 12AX7LPS - thin sounding but articulate. Kind of similar to the EHX tube, but without the growl.


  14. A better test (for flatness) would be to put the Grand Prix in your effects loop (if you have one) or use the preamp out of the GK into the GP back into the power amp in (if it has one).

    Yes, the GP should sound similiar to SWR pro series amps/preamps. You can run the GP into the power amp in on a SWR amp to A/B it against the built in pre.
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