My Boogie farts too easy

Discussion in 'Amps and Cabs [BG]' started by Psychdave, Apr 12, 2005.

  1. Psychdave


    Apr 4, 2005
    Valencia, CA
    Mesa 400 with a roadready cab, the stock speakers were replaced with JBL D-140. I have a thing for that JBL sound, but I am afraid the 400 is pushing then too hard. It seems to fart way too fast, long before I get to the "I'm going deaf here" volume.

    I have not toyed with the amp yet, the guy I got it from said he had it "biased cold" to save tubes, so I know I have to get that looked at.

    2 things I'm thinking: the bias is way off and I'm hearing the amp run out of gas or the D-140s won't take it.

    also: does getting rid of the 6L6s and replacing with 6550s make a substanial difference.

    Bass is a Rick 4003, music is blues, rock, classic rock. Would love the sound of my old Marshall Plexi with 2 Sunn 200s cabs. I thought this would do it, and it is really close, just not as loud as I would have thought.... or I have gone deaf, always a possiblity.

    Thanks for any input guys!!
  2. jdombrow

    jdombrow Supporting Member

    Jan 16, 2002
    Colorado Springs, CO
    It's quite possible the cabinet and speakers are incompatible. The dimensions of the box (and the ports) are designed around a particular driver, based on it's TS (Thiel-Small) parameters.
  3. tombowlus

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

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Did he have the amp modded? It is my understanding that all Mesa Boogie tube amps have a fixed bias.

  4. AlembicPlayer

    AlembicPlayer Im not wearing shorts

    Aug 15, 2004
    Pacific Northwet, USA
    bingo.. old are the power tubes?
    old worn out power tubes will sound like pooh
  5. Psychdave


    Apr 4, 2005
    Valencia, CA
    The tubes are new.. as in Chinese new, not my favorites, so that is part of what I am looking at, I too thought the Boogie was fixed bias, so I surprised when he said his tech had "set the bias". I think the first part here will be to have a good tech look it over and tell me what is going on.

    I have no idea how old the preamp tubes are, I do want to replace those with some NOS tubes. Anybody have any hot suggestions on tube combinations in this amp? I'll probably have to play a little bit, the gain configuration seems okay even as it sits but the nice part is being able to play with the gain.
  6. The 400 is probably pushing them too hard. The D-140's were only rated for around 100 watts weren't they?
  7. metron

    metron Fluffy does not agree

    Sep 12, 2003
    Lakewood Colorado
    You shouldnt need to replace the preamp tubes. Only if you want to of course. From what Ive read, adding a user bias to the 400 is not too difficult.

    I can only speak about my short experience with playing a 400+ through mesa cabs at a store. I felt the cab farted out pretty quick as well. It just couldnt handle the 400+ and I wasnt pushing it too hard. It was only a 115 though. Personally I would look at other cab options.
  8. jdombrow

    jdombrow Supporting Member

    Jan 16, 2002
    Colorado Springs, CO
    Before you spend any money, you should find another cabinet and head to use for troubleshooting. You need to define the problem. Try another amp with your cabinet, and another cabinet with your amp.
  9. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    The 400+ has a low F.R. (fartage ratio) so it may be the JBL's. Back when they came in many bass cabinets they were being driven by amps like the Fender Bassman , the Ampeg V4B , the Sunn 200S or the Acoustic 150. Low wattage and high fartage ratio. I've owned all of these amps beginning with the Bassman in 1964, so don't even think about telling me how powerful these amp heads are. Efficient cabs or not, these amps have a higher fartage ratio than some combo amps. But their wattage worked well with the JBL's. Maybe the 400+ is too much. :eyebrow:
  10. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY
    Something else to consider...

    If the 400 has the same tone stack as the 400+, then 'flat' on the amp is:

    Mid: 10
    Treb:0 (or close, I believe .4 for real)

    If you're used to setting up yer tone as a 'regular' amp, with bass at 5 as flat, then you're actually booting bass quite a bit. You may just be pushing the low end too hard.

    Old power tubes could also contribute...My Personal choice for mine is JJ's from Eurotubes...but there's lots out there.
  11. Psychdave


    Apr 4, 2005
    Valencia, CA
    Yeah that seems sensible, its not like I don't have other cabinets around.. I'll try my Aguilar GS112 with it to see if the amp is distorting early, I think the power range should be okay. My "backup" amp head won't tell me a lot about the cabinet but maybe I can find another head to throw on top.

    Regarding power and the D140s, I hae been worried about that, I have been told anywhere from 75-200 per speaker depending on how you define power rating. The Boogie probably produces more power than these speakers can handle.
  12. Psychdave


    Apr 4, 2005
    Valencia, CA
    Well it is a 400 not a 400+ so that helps a little, but I am thinking power is part of the issue, my concern is it seems the SPL is too low. Memory says the Plexi and one cabinet with JBLs was much louder with very little FR (Thanks, nice abbreviation)

    I will try it tonight with the little Aguilar and see what the volume looks like, with the tone controls in different positions, yes I have all the tone controls at "5" to start with, EQ out.

    Thanks guys, geez.. what a GREAT resource!!
  13. Funkengrooven

    Funkengrooven Turn it down? You gotta be nuts!!

    As a JBL Fanatic :hyper: I can tell you that not all cabinets are designed for D/K/E-140's.
    The speakers work very well in the right cabinet and very badly in the wrong cabinet.
    If the cabinet does not have the correct internal volume and/or the correct porting to support the D/K/E-140's then find the speakers that match that cabinet and use them... or put the JBL's in the right sized box.
  14. Psychdave


    Apr 4, 2005
    Valencia, CA
    Okay... about 90% operator error. :eek: Dialed the tone controls to the suggested position (bass and trebel almost at zero, mids up around 8) and started over from there.

    I was paying way to much atttention to volume and not near enough to the tone, WAY TOO MUCH BASS BOOST! Anyway, need some boost through the little Aguilar but the Boogie bottom really doesn't seem to need any.

    Still going to have the amp checked, re-biased and probably retubed with 6550s. Might swap my old EV SROs into the cab and see if the JBLs don't like the cab.

    It sounds much better!

    Thanks guys!! :)
  15. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY


    I got my 400+ not so long ago, and woulda set it up as I would with a normal amp until someone here tipped me to it. Its sounds great once you know where 'ground zero' is!

    My set up looks like this with a passive bass:

    Bass: 4 (for kickin' low end since it's reggae time!)
    Mid : 8 to 9
    Treble: 1

    I don't know if your amp has the pull-shifts, but I use them both OUT. This shifts the bass band up to low mids and the treble band down to upper mid/lower treb.