[lunasparks]

Couple things......

1)Flaky Reverb on these, after 3 tanks and the resistor mods, I said screw it and I use a Holy Grail Nano put right before the Amp input (and have run it in the loop as well, more on the loop in a minute, because the loop doesnt work as loops do now, and the mark 2a I think was the first, if not one of the first amps with a loop). The Nano, for GD material sounds great and better than the couple different tanks I had onboard. However, even if you dont use a reverb tank in that amp, keep a decent 12at7 in the reverb driver tube and make sure the reverb level on back is set to something, as it does still affect the gain in the signal path

2) You mentioned muddy:
CRANK the prescence on the back. Mine is set to between 8-10, depending on room. Try it all the way on 10, it will sound bright to you, but if you heard Jerrys amp out of band context it probably would have sounded too bright too.

3) Dont use the Second Channel, Lead drive, Lead gain, or lead master. Simply use the first channel which would be the firsts gain pot all the way on the left (cranked) and the first Master Volume. Push every other Push/Pull Pot IN (or make sure foot switch is set for channel 1 )Also, dont use the EQ, defeat it.


First 5 knobs is all you need on the mark2a for Jerry (and presence on back) , everything else other than that defeated.

Gain1: 8-10
Treble:8
Mids: 7-8
Bass:1-2
Master Volume to taste (on a loud stage in 60 watt mode, I rarely if ever find the need for 100 watt, my master never goes above 3.5!)

What tubes do you have in there?

You want to think of this Amp like a Twin. Use it for its cleans and use pedals for dirt.

Thanks! I'll have to figure out what, if anything, I'm going to do about the reverb. I've run it through my Line6 M13 ('63 Spring Reverb) and that sounds pretty good, actually. Maybe it'll stick.

Agreed on Channel 2. Now that thing is just pure mud, like if I dial in Channel 1 just about right, it's basically impossible to switch to the lead channel and get a useable tone. Kind of a head scratcher.

I haven't looked through the preamp tubes, but power tubes are Mesa branded. Could be that it needs some fresh/better tubes.

After playing with it for a while, the Presence knob is difficult for me to get comfortable with. You're right, it can get very bright...but I can't decide if it's doing so in a way that I like. Seems to me there's some trading off between how high I have the mid dialed vs. how high Presence needs to go to kind of balance it out. I'll be fooling around with this one for a bit, I know.

[lunasparks]

oh and as far as the preamp tap,

are you using the one on the underside of the chassis? That is the one to use.

Yes, this is the one I plugged into. But I was expecting it would basically totally circumvent the amp's power section. Maybe it shouldn't? Can I plug into that jack, send the signal out and then just disconnect the speaker on the amp itself? I didn't do this b/c worried about not having a load on power tubes that seemed to still be active; didn't want to fry anything! What do you think?

[lunasparks]

Also, just my 2 cents so far. I dig this amp and like what it seems to offer. But it's a bear to dial-in, I think. End of the day, though, for those who've been curious about the amps, my early assessment is that it's not quite as tasty as my SMS-MC250 configuration--so far still the high water mark for me!

[tigerstrat]

oh and as far as the preamp tap,

are you using the one on the underside of the chassis? That is the one to use.

Yes, this is the one I plugged into. But I was expecting it would basically totally circumvent the amp's power section. Maybe it shouldn't? Can I plug into that jack, send the signal out and then just disconnect the speaker on the amp itself? I didn't do this b/c worried about not having a load on power tubes that seemed to still be active; didn't want to fry anything! What do you think?

take out the power tubes (then you can disco the speaker) and use FX Send

[jeffm725]

TS is right, you can pull tubes and then unplug speaker. OR you can use a dummy load instead of the speaker if you dont want to pull the tubes. It is just a pigtail with a resistor. Unplug the speaker and plug in pigtail and you are good.

Yes Mesa's are KNOWN to be a bitch to dial in, but once you find the sweet spot, I think you'll dig it.

That second channel is dark and muddy because that is the saturated "santana" channel. Sustain for days and really compressed. Not a Jerry sound. Jerrys sound lies in the clean section of that amp, but the Mesa just gives Jer's clean some more hair.

Do you have the actual specific Mark2a manual. It is very helpful, and Mesa doesnt have it on their site. I can email you a copy if you want.

[tigerstrat]

TS is right, you can pull tubes and then unplug speaker. OR you can use a dummy load instead of the speaker if you dont want to pull the tubes. It is just a pigtail with a resistor. Unplug the speaker and plug in pigtail and you are good.

Yes Mesa's are KNOWN to be a bitch to dial in, but once you find the sweet spot, I think you'll dig it.

That second channel is dark and muddy because that is the saturated "santana" channel. Sustain for days and really compressed. Not a Jerry sound. Jerrys sound lies in the clean section of that amp, but the Mesa just gives Jer's clean some more hair.

Do you have the actual specific Mark2a manual. It is very helpful, and Mesa doesnt have it on their site. I can email you a copy if you want.

I still believe Jerry used the lead channel here and there... check out Masterpiece from 3/1/80. I wouldn't use a dummy load- why wear out your tubes when you aren't even using them? Plus you are increasing heat to the whole amp (I would think).

Tom

[lunasparks]

Thanks again, guys. I do have the iia manual (had to dig it up on google from some French website) and it helped clarify some things--plenty of bells and whistles with this thing, for sure.

If I run it as a preamp, I think I'll just pull the power tubes and unplug the speaker. I'm planning to use it as a combo anyway, but interested to test it as just a preamp through the MC250; only an experiment so I wanted to make sure I don't fry anything!

As for 3/1/80, I bet it's possible that Jerry used the lead channel, but from what I can tell with my amp, he must not have been switching between the two channels. It seems almost impossible to get anything Jerry-like out of BOTH channels at the same time. For example, if I dial in a gritty (but still Jerry) tone on the lead channel (seem to have to use the EQ to get there as well), the instant I switch back to channel 1, it sounds all wrong and I have to change everything again. Is the idea that he just set up the lead channel, dialed it in, and stuck with it for the song/night? On that note, if anyone has solved the mystery of getting good Jerry tone out of both channels without re-dialing, I'd be interested in hearing about it!

[tigerstrat]

As for 3/1/80, I bet it's possible that Jerry used the lead channel, but from what I can tell with my amp, he must not have been switching between the two channels. It seems almost impossible to get anything Jerry-like out of BOTH channels at the same time. For example, if I dial in a gritty (but still Jerry) tone on the lead channel (seem to have to use the EQ to get there as well), the instant I switch back to channel 1, it sounds all wrong and I have to change everything again. Is the idea that he just set up the lead channel, dialed it in, and stuck with it for the song/night? On that note, if anyone has solved the mystery of getting good Jerry tone out of both channels without re-dialing, I'd be interested in hearing about it!

Well, I'll clarify that mine is actually a Mark III, but a one of the very early "No-Stripe" ones that used the leftover Schumacher transformers from the IIC+ (incredibly loud!) , and a fairly rare 60 watt-only/reverb/GEQ model with EVM-12L speaker. I've tried an E120 in the amp (including several gigs), but I might actually slightly prefer how the amp likes the EV, which I just recently re-installed.

The best way I have found to get two independent usable tones, switchable between both channels, basically two things:
1) I set the main Gain control fairly high, like 5-7. This gives the lead channel the juice it needs and also seems to increase the reverb response, while adding only very mild dirt to the clean sound. I tend to have my Fender DSR's Volume set fairly high also.
2) Set the EQ switch to the center position, which activates it only in Lead mode (is this the case with Mark II also?), allowing one to set the tone knobs for optimum Clean tone, and the EQ to make further adjustments just for the Lead channel.

[jeffm725]

Not so experienced with the Mark III, but I will say that I CANT (and Ive tried) find a balance for channel switching on the Mark2a. There are several shared controls between the channels and what sounds great on channel 1 sucks on channel 2 and vice versa..

I concur on the 3/1/80 Masterpiece that there are 2 different levels of Dirt, and one of them could very well have been channel 2, but I have found that for me, using it clean with a Dist + for dirt works best

Also,For Me, the speaker that Brought this amp to life is a K120. I had an E120 in there, didnt sound as good, and I like the EV I had in there too (a nice one) but not as much as the K

[jeffm725]

............oh and TAD 6L6GC-STR's are great in this amp (unless you want to spend a fortune on Sylvania STR 387's or 415's)

[lunasparks]

2) Set the EQ switch to the center position, which activates it only in Lead mode (is this the case with Mark II also?), allowing one to set the tone knobs for optimum Clean tone, and the EQ to make further adjustments just for the Lead channel.

Ah, the IIa does NOT have this in between EQ switch....money says that's why they put in the III, because there are no really useable switching settings on the IIa (at least that I can find).

Also,For Me, the speaker that Brought this amp to life is a K120. I had an E120 in there, didnt sound as good, and I like the EV I had in there too (a nice one) but not as much as the K

Can't wait to get the reconed K120 in this amp--hopefully next week!

[cmc64]

I just picked up a Mesa IIB head from a seller on ebay (although I think it may be a IIA) - and the seller was not completely honest with me. The amp has some issues - I won't be using the lead drive channel but given the fact that if I pull the "Lead Drive and Lead Master" pots to turn it on, all I get is a loud buzzing from the amp - no matter what the volume is the auditory level of the "buzzing' stays the same. The tube sockets are a little screwed up and when you put any effect pedal in front of it and hit the footswitch you get a loud electrical "crack" through the speaker (JBL K-120 2x12). I have tried all of my pedasl and several from friends and every single one does it. The input to the amp is not putting out any DC voltage but there is something definitely wrong with this thing. The bulk of the potentiometers are very noisy as is the entire amp. I spoke with Mesa - a general clean-up will cost $200 -> $300 - for what I paid for it that cost is fine. Service needed on a 32 year old amp is not overly surprising. It does not have reverb but the potentiometer is in place and it appears that the circuitry is there as well - Mesa said to perform the "reverb mod" an add a new spring reverb tank would run me about $80. Considering I used "Bill Me Later" and I have a year to pay it off (interest free as long as they get $54/month) I am not sweating it too much. Just eager as hell to play it. So a month from now I should have it back (it ships out tomorrow). No worries; I am patient.

All that being said and along with the noise, the clean channel has many tonal options as it stands now (and does sounbd quite good) - when brought back up to spec I think I am going to be a very happy guy.

My ebay luck for amps hasn't been too good recently but I did win my paypal dispute over my decimated McIntosh MC2100 so that cash will fix the Mesa. I found a really god guy via the S.F. Bay Area Craigslist - he was the source of the JBL 2x12 cab. The cab itself is a bit worn (B+ Condition) as it has been gigged with - but it is 13ly Finnish birch, built like a tank and the JBL K-120's are perfecto. It sounds great!! It is set up with the standard Hard Truckers' frontoaded aluminum clips but it has Trey Anastasio style grille covers. Those I'll keep for the time as my two cats are obsessed with the cab and are all over it and the last thing I need is a scratched up K-120. $400 plus shipping - couldn't beat that price.

I just am dying to get this Mesa back and in proper working order - I'll report back with good news in a month.

[Dude2Dude]

Volume 8
Treble 8
Bass 1-2
Middle 4 -5
Master 1 about 3
Lead Drive 7
Lead Master 2-3
Reverb 4
Prescence 4-5

Actually, Staemius (sp?) gave you some great starting points for a lead channel setting. Did you even try this?

The trick with these amps is to keep the Bass low. The treble also affects the gain; if you want more gain, keep it high. The tone stack comes after Volume 1, and affects both channels, and the Master 1 also has an impact on both the Lead and Rhythm channel. The tone controls are interactive with each other, and also have an impact on the gain (with the treble having the most effect).

To simply abandon the lead channel altogether is, IMO, silly. There's incredible, liquid and dynamically sensitive tone in there — much more so than, say, the revered IIC+ which is grainy and tight. Spend some time. Use your ears. IME, those who can't dial in the Marks are using their eyes, and past experience, as a guide.

[tigerstrat]

I'd advise finding a qualified local amp tech to do the fixes and saving a ton of shipping costs (not to mention worrying about it's safety).

[cmc64]

I'd advise finding a qualified local amp tech to do the fixes and saving a ton of shipping costs (not to mention worrying about it's safety).

I am in Pittsburgh and there is an authorized Mesa service center near Harrisburg (only a few hours east) - UPS Ground will have it there overnight and I have spoken with the tech at the shop an he and I are right on the same page. The joint is called "Full Custom Music Repair". I have to say that after hearing such rave reviews about how great the customer service guys were at Mesa Boogie I am sorry to report that they were quite honestly rude, demeaning and had quite the air of superiority about them. I could tell right off the bat when I first plugged in that there was something funky going on with the guitar input - any pedal turned on would elicit a loud electrical "SNAP" through the speakers and any cable movement at all would result in the same. I called Mesa and they told me there was absolutely no possible way there was anything wrong with the amp - it had to be my gear - so I had friends bring over their gear and lo and behold - still problematic. So i called up the extremely helpful Mr. Sarno who lead me through a few tests and when I did a resistance test on that input with my multimeter, I found that there was none. That input should have 1 megaohm of resistance. So I called Mesa back and reported to them and they told me that I was wrong and there was nothing wrong with the amp. So I looked up local authorized centers and the above shop was the closest. I called them up and spoke with Tim (the tech who answered) and told him about the noise. His first response -"Sounds like there is a grounding issue or the 1 mega ohm pulldown resistor is shot." We spoke at length and this guy really seems to have a very solid understanding of these amps so as I just got paid today, it's headed out on Tuesday when I am off and get can it to UPS. Shipping is CHEAP and I'll have it back in a few weeks. That will be one wonderful day.