400+: Not enough gain?

[LiquidMidnight]

Hey everyone,

I have a Mesa 400+. Lately, it just doesn't seem to have the amount of gain and volume that it should. At the gig last night, I plugged into a 4x10 and 1x12 and could not get a somewhat satisfactory stage volume without having the channel and master cranked (thus going into clipped tube amp territory). I plugged in my solid state equipment and about leveled buildings. Also, my Eden 300T, which though is rated at 300 watts, but is most probably more around 200 watts, seems to be blowing the Mesa away in terms of volume.

All of the power and pre tubes light up and seem to have the correct glow. Do you think that it could be a preamp tube problem? I suspect that the amp has some burnt capacitors in it. It's an old and somewhat cantankerous head. I've already tried different speakers, cables, power outlets, and simplfying my signal chain; the batteries in my active basses are fine.

I was just wondering if there were any suggestions before I take this into the tech. Thanks.

[RickenBoogie]

Just take it in for a looksy- was the 410 and 112 plugged into the proper load output? ie: did you match ohms?

[BassmanPaul]

Without being able to test the tubes you could try changing out the pre-amp tubes. If doing so makes no difference its Tech Time.

[LiquidMidnight]

Thanks guys!

And Rick, I was definitely plugged into the proper impedance taps. I've been noticing the lack of gain for a while, though.

[JimmyM]

if it's getting cantankerous, i would definitely take it into the tech just to be on the safe side. i'd still try swapping out a 12ax7 or two first, though.

[LiquidMidnight]

I knew I could count on you to reply to this thread, Jimmy! *lol* That's probably what I'll do. I was planning on taking the amp in for general maintenance anyways. I've just been putting it off because my tech lives 45 minutes away. Turn around is slower than I'd like; but he's busy, because he's good. Plus, his rates are awesome. I have enough pro-quality amp gear sitting around that I can use to gig with for the next couple of weeks.

[JimmyM]

i'm really bad about posting on everything, huh? i should slow down with this internet stuff.

[Kahooli]

Originally Posted by JimmyM

if it's getting cantankerous, i would definitely take it into the tech just to be on the safe side. i'd still try swapping out a 12ax7 or two first, though.

As always, if you're swapping out output tubes, check the bias afterward.

[anderbass]

I was wondering what tone knob setting you were using? (you'll need your Mid knob set somewhere between 8 and 10 to achieve the amps full clean-ish volume potential)

If your not using your Effects loop, make sure your Effects blend knob is set to 0.

If you use your EQ, see if turning it off restores your volume.

If non of those helped your problem, a really easy test would be plugging your Bmax preamp into the 400+ Effects Return jack. If this restores the Mesa back to its former volume levels you could then be a bit more sure that swapping preamp/driver tubes might help.

[LiquidMidnight]

Anders, thanks for all of those suggestions! I'll try them out after I eat dinner here in a little bit. I do know that my FX blend is NOT at 0 right now. I also didn't even think of running my Bmax through the loop to see if the issue is with the front end.

Kahooli, actually, all Mesas are fixed bias - a blessing or a curse depending on how you look at it.

[LiquidMidnight]

Update: Anders, you are brilliant, my man. It was the FX loop. One of the house engineers we use often runs a DI from the loop since the output gain from the head's DI is not adjustable and can get out of control at the board. I never turned the level back. Turned it back and I was ready to send the speaker through the grill of my cab.

Thanks again!

[sleepytime]

That'll be $39.95.

[thudfromafar]

Originally Posted by sleepytime

That'll be $39.95.

[Ajrocks]

might want to check your cords. I was at a gig once, had just bought a monster cord. that was 10ft.
during check sounded great. then I realized I had a more stage so switched the pedal to the 10ft and the older generic cord into the bass(20ft) lost a lot of volume. Also had cheap cords going from the cabs to the head, new proper cords made a huge difference.

Also check to see if you need a new battery in the bass if it's active.

[anderbass]

Hey that's cool, your welcome.

[Alex1984]

TB solves another mystery!

I was confused by the title at first, "400+" and "not enough gain" do not belong in the same sentence!

[MK1]

I would use the line out instead of the FX loop to feed the FOH. You should be able to run it straight to the board or you can use a DI with a pad. I've always used that instead of the DI out, the level is fully adjustable and it doesnt change the stage level at all like the FX loop would.

[rockstarbassist]

Glad you got it sorted out!
B/c yeah, my 400+ with Master at 2 and Channel 2 at about 3.5 makes most FOH engineers mad b/c I'm competing with the PA system through a 610 at that point! :LOL:

[LiquidMidnight]

Update: Even after getting the FX blend figured out, the amp still didn't seem to have a lot of clean headroom on the next gig I played with it. I could play in my living room with the Master and Channel volumes on 8 and it sounded like I was playing through a practice amp. I noticed that the amp was kind of noisy at the last gig, perhaps a little microphonic sounding. I took ander's advice again and ran my BBE pre through the FX loop. The amp seemed to be really clean with the Master up to 10. So I ordered a set of Mullards for the Mesa's preamp.

Holy crap on a stick! The difference was not subtle at all. It was like the Gain Fairy came and left 12 db of extra headroom and 175 more watts under my pillow. It's unbareably loud with the Master on 5 and Channel 1 on 1. Plus, the tone quality is excellent, very clear and tight. I used my Eden and BBE rigs on my last two gigs, but the Mesa shall be rocking again tonight! I can't wait.

I bought the amp used and retubed the power section about a year and a half ago. I didn't retube the preamp. There was a set of Sovteks in the pre. I have no idea how long they were in the amp, but my guess is they were in there for a while.

[Nightlyraider]

LiquidMidnight, you might want to try turning down the master and up the channel gain levels. Having the master on 5 is insane volume with my 400+, but Channel 1 is usually 7-8ish.