Mesa 400+ help... REPAIR ISSUES

Discussion in 'Amps and Cabs [BG]' started by garmenteros, Jan 13, 2009.

  1. garmenteros

    garmenteros Bass Enthusiast

    Aug 24, 2008
    Dominican Republic
    I have a mesa 400+ running into a powerhouse 1000. The other day some tubes fried both preamp and power amp tubes. Also had audio output transformer die. But a tube kit from tube depot. REISSUE tungsols for the pre, sovtek 6l6s for the power. Bought the original output transformer from mesa. Had my tech install all this in the amp...

    Take the amp home. I cant hear a thing its as if nothing was done to it. I just flipped the amp on from standby after 5 minutes of heating up. Nothing. with all the controls up to 10 i get some hiss. And the master volume knob is scratchy and it wasn't before. The other knobs arent scratchy. Im mad. Ive just spent a fortune trying to get my dream amp working WHICH I GOT NEW 7 months ago.

    By the way just to confirm how to do things, I connect the 4 ohm jack on the powerhouse to the 4 ohm jack to the left of my 400+. There are multiple stacked 4 ohm jacks to the right of this but I figure its for getting two 8ohm loads down to 4. Can someone confirm this for me?

    Anyways, I got thinking. I left the amp on for 3 hours and took a nap on standby. Got up the amp was working but at like a quarter of its strength, the sound was there, though there was some distorting like sounds on the E and B strings...

    Could the master volume control be causing all this? Since the tubes are new do they need to be broken in to be loud as well as the new output transformer... do these things need to be broken in?
  2. garmenteros

    garmenteros Bass Enthusiast

    Aug 24, 2008
    Dominican Republic
    One more thing, how long should I be heating this amp on standby before flipping it on?

    BTW I have a furman AR 1215 Regulator rack mounted with it.
  3. Sounds like your tech didn't do his job. Tubes and transformers do not require breaking in. Your amp tech might?
  4. Should be ave. of 2 min. max.
  5. DanRJBrasil


    Jun 10, 2007
    take it back to the tech or get your money back and take it to a good one
  6. mikeswals

    mikeswals Supporting Member

    Nov 18, 2002
    Seattle / Tacoma
    Your tech didn't do something right.
    But if you only bought it new 7 months ago, isn't it under warranty???

    In reguards to the standby switch; when I'm in the recording studio I leave my Bass 400 or B15R on all day long, and it's left on standby most of that time, I flip it on to lay something down, then back on standby for another few hours.

    Your speaker jacks on the head are laid out like this:

    O O

    OO OO
    4ohm 8ohm

  7. garmenteros

    garmenteros Bass Enthusiast

    Aug 24, 2008
    Dominican Republic
    so I am in fact connecting my amp the right way? i connect to the bottom one on the left...

    The thing here about techs in this country. they dont exist. Getting EASY EASY FIXES like changing an input jack or changing a filter cap r determining if one's values are no longer as should be is an EPIC BATTLE. Im seriously considering just having all my amps go to the states for check ups every two years but might have to start early with this one because I already have 600 dollars down the drain. about 250 in tubes and that brand bew mesa audio transformer.

    Any other suggestions are gladly taken like where to send it etc.
  8. GeneralElectric


    Dec 26, 2007
    NY, NY
    I still don't get why you needed to pay for the transformer. Its under a 5 year warranty.
  9. rpsands


    Jul 6, 2007
    That sounds like a broken or failing input jack, almost exactly. I just got a used mesa 400+ from a forum member, and I had the exact problem you describe when I got it, except it wasn't consistent -- it wound cut out by making a scratchy sound and then going to 25% volume. I moved the input jack around and it works fine 100% now.

    The scratchy sound is exactly like what happens when an input jack on a bass fails. Not sure if yours is like that.

    You might want to try checking that out before you panic. They're like 2.50 to replace.

    The input jack is something with a soldering iron and minimal internet training you could fix yourself.
  10. garmenteros

    garmenteros Bass Enthusiast

    Aug 24, 2008
    Dominican Republic
    you mean on the bass or the amp? both of the amps inputs have the same volume problem. I TRIED several basses and various cables. You would just recommend 2 new input jacks for the head?
  11. rpsands


    Jul 6, 2007
    I'd think on the amp more than the bass. I would try wiggling the input jack and holding it in various positions and see if it modifies your issue.

    It's definitely possible this is not the issue but it sounded very similar to my problem :)

    You can also try Mesa's tube troubleshooting FAQ (tapping them and what not).