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Hi Folks, I'm looking for some definitive information on what preamp tubes perform what function in a non reverb amp. I know that on the reverb model 2 tubes are being used for the lead channel.Half of V3 and half of V4 are for lead drive with the other 2 halfs of each tube being used for the...

Hi Folks. I need a few new pots for my Mark IIB.Lead drive(push pull) and treble pot definitely.Maybe the middle pot too. Could someone tell me the correct pots to get for the Mark IIB please? I've had a look on google and tube doctor site but there are a few different ones. Any advice is...

Hi Folks. My Boogie Mark IIB is blowing fuses sporadically. It's been recapped and has new Mesa power tubes with hardly any use at all. This amp is a 60 watt model but has a replacement power transformer.It is a 100 watt Fender Export PT from a dual Showman I believe?It also has a Fender choke...

Hi Folks. I would really appreciate if fellow Mark IIB owners could give me their opinion on my amp. I've always heard that the Mark IIB has loads of clean headroom?Mines hasn't and has a very gainy "clean" channel.I can get a lovely clean but volume 1 has to be down around 4-5. I've posted a...

Hi folks. Could any of the more knowledgeable guys on here please tell me what I would need to have done to an SOB 60 watt combo to make into a mark 1 or as close as possible? Mine has the limit control which I never use.I would like to have a presence control added too in place of the limit...

Have any of you tried the older EI 12ax7/7025 tube in any mark amp? I got a NOS(what I think is a) Groove Tubes EI 7025.Long smooth plates.I've read they sound great but can be prone to microphonics.Is this the case with the older ones too? I'd be interested to hear other folks...

Hi Folks I would really appreciate if someone could take a quick look at some pics of my Mark IIB. The treble cap(ceramic)on my Mark IIb looks really worn and I was wondering if this can have any detrimental effect on the tone at all? I would also really appreciate if anyone could have a look at...

Could anyone tell me what would be required to mod an SOB to be more like a Mark 1 please?Apart from the limit control(which I never use)what other changes were made to the circuit and what would need to be done to make it a Mark 1?

Hi folks. Does anyone know why Mesa nearly always used 5% tolerance 470 ohm (Gold band) carbon comp screen grid resistors in the 60 watt(2 x 6L6) amps but mostly always used 10% tolerance(Silver band)for the 4 x 6L6 (Non Simul Class)100W amps? I've got 10% tolerence 470 ohm CC's screen grid...

Hi folks.So I took my mark IIB out to gig yesterday as I have been really enjoying it at home but the problems with this amp continue.I had my volume 1 at 8-9 and the master at 2-3 but I had to have the lead master way up at 7-8 to have it around the same level as the clean channel.What could...

Hi folks. I've read of the problems associated with the effects loop in the 2B and the effects loop Mod but I thought the issues were only with the Reverb equipped amps and the lead channel? My 2B,Non Reverb/Eq sounds terrible with my delay pedal through the loop.The delay repeats are distorted...

Hi guys. Can anyone tell me what the original preamp tubes Mesa would have shipped the Mark IIB with please? This is a Non reverb model so 4 x 12ax7's. There were 4 x GE 12ax7/7025 in it but they're Fender "Special Design" Labeled? Would Mesa have used Fender labeled tubes or are these likely to...

Hi Guys. I'm wondering if the tone stack on my IIb is behaving as it should? I have to have the treble up full to have just a moderate/normal amount of treble. It's a non EQ model. Also I don't like using the presence control as it's a bit too harsh sounding for me but if I have it at 0 it...

Hi folks. I've got a pair of Sylvania big bottle 6CA7's and I'm wondering what the difference in tone/feel would be with these in a Mark IIB? The Boogie has a bias pot installed and these were actually in there when I got it but I didn't actually hear what they sounded like as I put the amp in...

Hi folks. I've just noticed that there is a shot resistor in my SOB.It would seem it's been like this since I got it so I'm not sure how it's affecting the amp. Could someone tell me what this resistor is please and what it affect is on the amp?It's the first carbon comp resitor...

A couple of questions. Can anyone tell me what make of tubes these are please?They're labled Peavy. They were in my Mark 2B when I got it. There were a pair of these 6L6's in the bottom of the amp. I took the EL34's out and put in the 6L6's and the amp's fuse blew.Do you think it would have...

Hi Folks. I had some work done on my Mark IIb recently and had the screen grids returned to carbon comps.I have just noticed that a bit of the trace on the PCB at the screen grid has been lifted off with the solder of the old component. Will this cause any problems?If so how should this be fixed?

Hi folks. I had my Mark IIb Fully recapped,bias caps too and after getting the amp back there is a loss of gain.I have tried swapping tubes about.There is no loss of volume just gain.With the lead drive at 10 I get only slight singing leads but nothing like what it should be.With a strat(Single...

Hi guys, Has anyone here replaced the 470 ohm carbon comp screen grids for the metal film type? When having My Mark IIb repaired I also wanted it restored to stock and for the tech to return all replaced parts to original. He done all of the work but was a bit hesitant to install Carbon Comp...

Is anyone still running their vintage amps with the original preamp tubes? My Mark IIb has just been in for a service and the tech replaced the output tubes with new Mesa STR 440's.He left the preamp tubes in but they are years old. They are General Electric Fender stamped made in USA tubes and...