My used Mark V combo lacks bottom-end (issue??)

[Jazzdarkside]

Hi

I just got used Mark V combo day ago after I've tried it out the result was .. I felt like it lacks of bottom-end (I used to play Mark V head version through 2x12 recto cab) the bottom-end was a lot less than it should has. Of course I realized that combo version is "half open" so the bottom-end loosing there but this case I did try with 4x12 recto and the result still remain the same. Even I tried to turn "Bass Knob" to max it didn't help much.

So, Do you have any ideas what's going on to my Mark V or any of you guys here ever facing this situation. I would appreciate to see you guys's opinions before I will send it to tech here.

thanks

 

[LesPaul70]

The shortage of bass frequencies in the C90 combo is to be expected, I guess. But you certainly should not be experiencing that (compared to the head version) through a Recto 4x12. Unless there's an impedance mismatch. You were using the correct impedance jack, right?

By the way, in my experience, the bass pot is not the most effective way of getting more 'thump' out of your MkV, it tends to add mush rather than big bottom to your sound. The graphic EQ does a much better job there. Or even better, you could put an EQ pedal in your FX loop. Not that you really need one with a MkV, you must certainly don't...but I have one, and I just love how it allows me to finetune - or even completely reshape - the frequency structure of my Mark V sound. (And also boost/cut volume when I need to.) I guess I've already become addicted to my cheapo 1980s EQ pedal in the loop. Even though it's very much not needed with a Mark V.

...Which reminds me of something - are you using your FX loop? It's a parallel loop, and depending on what's in your loop (and how your FX loop send/channel Master volumes are set up), you could end up cancelling frequencies. Which in turn can often cause symptoms like the lack of bottom end. Below the FX loop send pot, there's an FX loop hard bypass miniswitch which removes the FX loop and the associated preamp valve completely from the amp circuit. If you are not using that miniswitch already, try doing so, and see if that makes a difference.

Of course it could just tube (or even amp) malfunction...

 

[Karl Houseknecht]

are you using your FX loop? It's a parallel loop

It's a series loop, right? At least, mine is. The level control is just a send level control, not a mix control.

 

[Laskyman]

Pretty sure Mesa only uses serial effect loops from 2009 forward on all production amps with a single loop. Mark V is serial

 

[LesPaul70]

Mark me wrong there, then.
I had just assumed it was a parallel one because in my experience it is entirely possible to get an ugly 'out-of-phase' like sound from your effects loop when using effects if you set your FX loop send and channel Master (=FX loop return when the loop is engaged) values too low.
Plus, there's some sound, however faint, even when you set both to zero, at least on my Mark V.

Those observations made me think it was a parallel one, but apparently I was mistaken.

 

[bandit2013]

Hi

I just got used Mark V combo day ago after I've tried it out the result was .. I felt like it lacks of bottom-end (I used to play Mark V head version through 2x12 recto cab) the bottom-end was a lot less than it should has. Of course I realized that combo version is "half open" so the bottom-end loosing there but this case I did try with 4x12 recto and the result still remain the same. Even I tried to turn "Bass Knob" to max it didn't help much.

So, Do you have any ideas what's going on to my Mark V or any of you guys here ever facing this situation. I would appreciate to see you guys's opinions before I will send it to tech here.

thanks

What power tubes and preamp tubes are in use? The power tubes would be the primary cause for low bass intensity, preamp tubes may also contribute to loss of low frequency but doubtful. If you have recently replaced power tubes, preamp tubes and still have same issue, do not forget the rectifier tube. I typically use the 90W power modes in all channels. I was having similar issues, lows would not be as bold as they used to be. Once in a while the highs would be dominant then change. I recently replaced the stock rectifier tube and it made a difference. Lower frequencies require more power from DC supply. The tube rectifier is always in the power supply circuit. The diode select switch will parallel the tube with diodes but does not remove it from providing power to the 448v dc supply. Since this tube needs replacement just like any other tube, it could not hurt to get a spare and see if this cures the low frequency issue. Just a suggestion.

 

[screamingdaisy]

Make sure the FX loop send knob on the rear is in the centre detent position and not maxed out. It'll make the amp sound really bright and thin if it's maxed.

Beyond that, if something sounds wrong on a tube amp I usually look at the tubes first... Particularly on a used amp.

Lots of people will buy an amp, burn the tubes out on it, then sell the amp because it sounds like crap and they no longer like it.

 

[rabies]

try new power tubes and an extension speaker closed cab.

 

[bandit2013]

try new power tubes and an extension speaker closed cab.

I would agree with both tubes and extension cab. If you are used to the Mark V through a 2x12, the single MC90 just will not cut it. I also have a Mark V head that I run though a Mesa 412 cab. Tons of bottom and abundant highs too. In rude comparison, my Mark IV combo is a monster though the 412 cab, sounds weak and thin through MC90 speaker by itself. I also have a small 1x12 closed cab that I recently put in one of the old V30s that I removed from the 412. The Mark IV sounds fuller pushing both the MC90 and the V30. I would assume the Mark V combo would sound more complete with an extension cab.