MARK IV "farty" bass ..need help

[sunil999]

hey guys i have a mark IV and im experiencing a problem,,whenever i use the lead channel amd i turn the amp up...it seems the low end is "farty".settings posted below.please help me on this..thank you

lead gain 8 pulled
treble 6
bass 2.5
mid 6.5
lead drive 6
presence 2.5

eq traditional V,,,with mids (750 slider) in the middle line

 

[JOEY B.]

Turn up your treble knob to 7-8 and adjust your 240 Hz EQ slider down until the gas pains subside. Is this an open back combo amp?

 

[giorikas81]

Also don't be affraid to cut the bass down to zero (in the tonestack) and even leave it unboosted in the graphic. If you play a guitar with flabby low end it may be the one to remedy. Try an eq pedal before the amp and experiment with bass cut there also. Last link is the speaker/cab...

 

[sunil999]

Turn up your treble knob to 7-8 and adjust your 240 Hz EQ slider down until the gas pains subside. Is this an open back combo amp?

yes this is a open back combo but i hook it up to a 4x12

 

[dcgdc5]

Is this just starting to happen. Could be a pre amp tube. Try swapping tubes. Different manufacturers sound different. I know the Tung Sol RI's in my Fuchs sounded really "farty". The Mullard or JJ gold pin really tightened the low end.

 

[sunil999]

the preamp tubes are pretty new... 6 months old with not much play time

 

[dcgdc5]

try switching brands...even within brands tubes sound drastically different.

 

[sunil999]

you think its the power tubes or preamp tubes?

 

[SonicProvocateur]

What kind of 4x12 is it? You may have ear fatigue or wearing your cab out.

My 2x12 with Jensens sounded awesome at first but eventually the bass response started slipping as it approached 1000+ hrs on it. Now the cab has quite a different character, definitely flabbier on the low end, and less responsive highs. Its my cab, not my amp. But changing my V3 lead tube made a difference in harmonics and bass response. The cab sounds "filthier" now...more agressive, but alot looser, and not as bassy.

Ear fatigue hurt me too, hearing the same tone day in and day out; I forgot what I needed to hear.

 

[sunil999]

im using a marshall 1936 2x12 and a marshall 1960b 4x12... what tube are you using on v3? ill try it out..
i notice a crackle/fart when playing low registered chords (when i hit the open string or 1st fret chord) its really annoying help please

 

[SonicProvocateur]

I was using a vintage Mesa STR12AX7, but it was too dark and grungy. I'm using a 2x12+4x12 setup too, btw. Killer volume and tone.

Switched back to an off-the-shelf Mesa Russian-2 12AX7. Much more articulate and harmonically rich.

 

[sunil999]

sonic,,,can you please post your settings so i could try them out..i doubt its my tubes im using jj preamp ecc83's..power amp tubes im using chinese 6l6gc

 

[normandk7]

I had that kind of problem when i was playing very loud and it was a bad cap...
Good luck!!!!!

 

[RR]

I had that kind of problem when i was playing very loud and it was a bad cap...
Good luck!!!!!

That would have been my guess too.