Mark IIb farty lead channel

[SCREEM]

My IIb has a wonderfull clean sound but, the high gain sound is farty no mater what settings, even with the bass turned down all the way and at low volumes, at high volumes it starts to hum/squeel. the clean channel does not sound farty even at ear bleading levels of volume.

The power tubes look old as dirt as well as the pre's...is it supossed to sound farty in lead mode or do I just need to find wich pre tube is pooched?

 

[LesCarr]

IMHO Try a complete tube change If that don't work have the caps replaced.

 

[screamingdaisy]

I'd suspect your power tubes are worn out. Replace them.

As long as they're not microphonic the preamp tubes should be alright.

 

[Lester]

Are you using the effects loop on the amp?

My Mark IIB had a really crappy sounding lead channel...something like what you discribe. I sent it to Mike B for a refurb and while talking to him about my concerns he mentioned an issue with the effects loop that can be corrected with a mod. I had the mod done and now my amp sounds awesome on the clean and lead channels.

 

[RR]

... I sent it to Mike B for a refurb and while talking to him about my concerns he mentioned an issue with the effects loop that can be corrected with a mod. I had the mod done and now my amp sounds awesome on the clean and lead channels.

Didn't sound like the reverb improved too?

I had a simliar or same mod by Mike B. He said it will improve digital delay units running through the effect loop.

So would you say our MarkIIB is now a Mark IIB+?

 

[SCREEM]

I tryed an EH 12ax7 in all 5 slots with no change, also put in my new TAD6L6GC-STR from my 5150 with no change in fartyness, I failed to mention it sounds farty on palm mutes....maybe its just how it sounds. I've got a full retube coming EH pre's and SED winged C's :roll:

 

[screamingdaisy]

I tryed an EH 12ax7 in all 5 slots with no change, also put in my new TAD6L6GC-STR from my 5150 with no change in fartyness, I failed to mention it sounds farty on palm mutes....maybe its just how it sounds. I've got a full retube coming EH pre's and SED winged C's :roll:

Have you tried different guitars? It could be your choice in pickups.

 

[SCREEM]

I tryed an EH 12ax7 in all 5 slots with no change, also put in my new TAD6L6GC-STR from my 5150 with no change in fartyness, I failed to mention it sounds farty on palm mutes....maybe its just how it sounds. I've got a full retube coming EH pre's and SED winged C's :roll:

Have you tried different guitars? It could be your choice in pickups.

yeah, my parker pm 20, my deluxe strat and my PRS CU22 AP, fartiness for all, power chords do sound good though and the clean channel is killer 8)

 

[screamingdaisy]

yeah, my parker pm 20, my deluxe strat and my PRS CU22 AP, fartiness for all, power chords do sound good though and the clean channel is killer 8)

I'm outta ideas. I remember a friend of mine saying that his MkIIB tended to lean towards the farty, sorta 70s vibe and couldn't really get a good modern sounding palm mute out of it.

I've also read a few times that Mike B (Mesa/Boogie) thought the IIB should've been called the IIB- as it was more of a step back than a step forward.

 

[SCREEM]

well I still love it, I use a ts-808 clone on the clean channel that gets me a good lead tone, so it's great for classic rock, my peavey's have me covered for blues and heavier stuff.

 

[hans-jürgen]

is it supossed to sound farty in lead mode

Short answer: yes. :wink: Longer answer: I had to tune the tone and lead drive circuit to find a working balance between good rhythm and gain sound, i.e. mainly less bass and adjusting the overall gain for the lead channel. I don't need shred-type overdrive though, because I'm playing in a ZZ Top cover band.

 

[Lester]

I have owned my Mark IIB since 1990. Until I got the effects loop mod done I was never happy with the lead channel...I stopped gigging with the amp 7 or 8 years ago. After the mod I had done by Mark B last December, I am so happy with the amp I am going to start gigging with it again!

You really should check this out!

 

[SCREEM]

is it supossed to sound farty in lead mode

Short answer: yes. :wink: Longer answer: I had to tune the tone and lead drive circuit to find a working balance between good rhythm and gain sound, i.e. mainly less bass and adjusting the overall gain for the lead channel. I don't need shred-type overdrive though, because I'm playing in a ZZ Top cover band.

yeah. mine does ZZ Top very well, got watch out for those farty mutes though :lol:

 

[Boogiebabies]

Every time I see this thread I want to name this amp.

Slartibartfast.


Sorry.

 

[LesCarr]

Who cut the cheezzzz :wink:
Excuse me but I'm sort of a newbie here I played guitar 26 years ago', and have riecently restarted, non professional but I did jam,back in the day, with people who giged on weekends and were profiecent musians. I don't remember any of this terminology
I digress,
I am not familiar with a lot of this terminology i.e. fartyness? etc.

Maybe someone should make a post describing the terms titled like GUITAR MUSIC TERMINOLOGY FOR IDIOTS

I owned shortly a Mk-IIb and traded it and a Cybertwin for a MK-IV I liked it but like the Mk-IV much more. As for the Cybertwin nice but no soul :roll:

P.S. - ZZTop a truely great band :!: B. Gibbons is a real Musicologist. And I am quoting none other than Slowhand (E.C.) himself.

 

[SCREEM]

I have owned my Mark IIB since 1990. Until I got the effects loop mod done I was never happy with the lead channel...I stopped gigging with the amp 7 or 8 years ago. After the mod I had done by Mark B last December, I am so happy with the amp I am going to start gigging with it again!

You really should check this out!

do you have a link to the mod?

 

[SCREEM]

Fixed, the tubes where dead, sounds great now and can do metal easily, no more fartiness. :twisted: the EH 12AX7's have more gain than the mesa tubes that where in there, ALOT brighter as well.... had to put the presence to 0 with these.

 

[LesCarr]

IMHO check the caps as well if they are original it will be well worth you time and money to re-cap. If they are like over 10+ years old I believe you run the chance of one or more going bad and causing serious harm to the circut board. recaping may even tighten the sound up even more I helped with mine

 

[Dirt123]

I'm very interested in the details of this mod too.
What does the mod involve?
How much does it cost?
It is something my local boogie service center can do?
I would have to ship my amp halfway across the country, & I'm pretty tight on cash.

My MkII is very basic, can an EQ and reverb be added at this point too? The only reason I ask, is that rather than upgrading the amp I have, it might be more worthwhile to just trade up.

Dirt

 

[LesCarr]

:idea: To find local service center OR find out what Mods. are still performed on MkIIb's by MESA Boogie tech's at their facility call Mesa'a customer service:
(707) 765-6565 Phax: (707) 765-1503
They have a friendly staff 8)