Any Marshall experts out there

What speakers does your combo have? If the stock Celestions have been replaced with some cheap substitutes, that could be the problem. I'm also wondering if the speakers could be wired out of phase--if so the cones will move in the wrong direction resulting in a major loss of low end frequencies.

A common problem with buying a combo amp at a music store is the known tactic of placing an open-back combo against a wall, which makes the amp sound much more bassier than it will positioned away from a wall. You could add a 2x12 extension cab as a means of moving more air.

ORIGINAL: Guitslinger

A common problem with buying a combo amp at a music store is the known tactic of placing an open-back combo against a wall, which makes the amp sound much more bassier than it will positioned away from a wall. You could add a 2x12 extension cab as a means of moving more air.

If this is the problem, you can just close the back yourself. Just buy some wood and attach it to your amp. But if it's really that silent, I think the problem would be more likely to be out of phase wiring or bad speakers.

Partially agree here unless I'm reading you wrong....

100w - definitely a must
4-12 is nice but the 100w combo (tsl122 is what I have) will rip your F**KING head off!!!!

Thanks for the input all...the out phase wiring has me thinking...How do I check this? Is it as simple as switching where the wires are hooked up? Or it could be like jamester says it's just weak...but its got 2 celestion's 2 EL-34's and four preamp tubes...I'm not trying to play metal I just want defined crunch but can't get it loud enough. Problem is I bought it used and good amp techs are hard to find where I live....and sending it anywhere is just not an option.. I would say there is a definite loss of low end but it's not just from the open back. How do I check the impedance?

It sounds like you want to check the polarity of the speakers to ensure they are hooked up the same? The easiest way to do that is to use a standard 9-volt battery and touch it onto the jack (Tip = positive, sleeve = negative) of the speakers. This will move the cones in one direction which you can see, or gently place your finger on the paper cone to feel the direction of movement. By doing this you can ensure that the speakers are both moving in the same direction. If you really feel that the power is lacking, it would be a good idea to have a qualified person check the power tubes for correct bias, correct tube to socket contact, and to ensure that one didn't go tits up on you. If you see arcing or sparks in a tube that's a pretty good sign that it's shorting out! It's possible in a class AB circuit for one to go bad, and the other to keep working...which will make the amp sound thin.

Anyway, I empathize with your plight and have some direct experience with these amps.
The JTM60 series came out around 1996, and being a huge fan of the early JTM45s (and because of Marshall's advertising claims) I figured I just had to have one. So, I got a JTM60 head. I played it at the house for about a month before taking it to a gig, and during that time I started developing doubts about its abilities. It has some pretty cool features and I liked the controls and layout, but at volume I found it becomes anemic. Anyway, I took it to a few practices and gigged with it a couple of times. Not a good experience at all. The cabs I use are Marshall 1960A vintage (with V-30s), big box closed back 2x12 Fender (with V-30s), Marshall 1965A (stock 4x10 closed back), or a couple of open back 2x12 cabs. So, the problem was no lack of speaker-age or selection to find a good cab mate. I come to find out from reading various BBS (like the Marshall and Telecaster Discussion page) that this was a common experience. Also, several folks complained about failing tubes, power transformers, or output transformers (I never had any reliability problems, though). I remember that I opened it up to see if there was anything I could change (I had made several clones of JTM45 and Plexi amps so I figured I could do something with it), but because of the layout and construction (which was not that great) I just closed it back up and called it a day with that amp and sold it.

If you are really jonsing for authentic Marshall tone, there are several very good DIY forums that can get you on the road to making your own JTM45, or Plexi, or 18 watt marshalls. All of these amps will kick the snot out of a JTM60. BTW, I've practiced with my 18 watt marshall and it cuts through the mix better and sounds much fuller than the JTM60 did.

I think for someone who is using it around the house or possibly for recording it might be a good amp...but I found that it sucks for playing out. I hate to be so negative about an amp, but my experience with the one I had didn't leave me with a much to brag about.
Best of Luck to you!

If by self biasing you mean it's a cathode biased circuit - Absolute NOT!
Any power tube change in the JTM60 series will require that someone open the amp up and adjust the bias pot (labeled rv101 in the referenced schematics) while measuring the cathode current draw. Do not just swap different power tubes into this amp thinking they will be biased correctly.

Pre-amp tubes can be swapped freely and are "self" biasing so-to-speak.

Go to Blue guitar page with jtm60 schematics for detailed circuit info.

ORIGINAL: Bamboo

If by self biasing you mean it's a cathode biased circuit - Absolute NOT!
Any power tube change in the JTM60 series will require that someone open the amp up and adjust the bias pot (labeled rv101 in the referenced schematics) while measuring the cathode current draw. Do not just swap different power tubes into this amp thinking they will be biased correctly.

I was skeptical of the 622 being a Class A amp, hence my doubts. On the other hand, there's a hefty window of bias settings that any amp can be set at and the bias still be within a safe operating margin. Popping a new set of matched tubes into an amp without setting the bias can't really hurt anything. I've used three different brands of tubes in my Marshall and the difference in the bias reading after swapping the tubes was only slight. Any adjustments made to the bias is typically a matter of fine tuning.

Yea it's a tube amp. I have not even looked at a Marshall in 20 years. Excuse my ignorance. But I found this LINK. Might find it interesting. Sounds familar.............JDW

I also suspect a phase problem, presuming all else is good.

SPL follows a logarithmic curve, meaning that a 10watt amp is half as loud as a 100watt amp, all else being equal-- but all else is rarely equal.

I am not surprised to hear that the fender is louder than the marshall (fenders tend to be LOUD), but I am suprised that it totally blows it away, volume-wise, as you seem to imply. That isn't right. A 60-watt marshall should be plenty loud enough to play with a drumset, a second guitar and a bass, and even a horn section for that matter. You might need additional amplification to fill up a gymnasium, but if your knobs are set to eleven, then you should be causing serious pain in a rehearsal studio.

Speaker brand should not make a huge difference. Crappy speakers or tubes will more likely be destroyed than be much quieter.

At the risk of being insulting, are you comparing the same signal chainwith the Marshall and the Fender? Like, you're sure it's not a bad battery in an effects pedal or something?

Most current guitar amps have the speakers connected by simple stak-ons, aka quick-connects. You can check for phase problems by simply pulling off the stak-ons from one speaker and reversing them. The amp should sound either twice as loud or half as loud after you do that. If it's twice as loud, the congratulations! you fixed the problem! nothing further is necessary. IF it's half as loud, then put them back, the probelm lies elsewhere. For the record, it will not damage anything to do this, and, although there is, technically, a "right" polarity and a wrong one, it doesn't really matter.

One further consideration-- Is your Fender a two-speaker? If so, then it may be that the Fender's speakers are connected in parallel, but the Marshall's are connected in series. Speakers connected in parallel will effectively double the output of the amp, whereas speakers connected in series will basically halve it (given the same speaker impedance). If this is the case, then you can rig up the marshall to be parallel, but you will almost certainly have to replace the speakers.

Also, are you using the same kind of gain structure for each amp? On almost any guitar amp (except maybe a marshall) the clean tone is going to be "louder" than the overdriven tone. On fenders especially, you are likely to get a very loud, punchy sound with lots of attack-- the marshalls will tend to give a more saturated, less dynamic sound, even on the "not overdrive" channel. Given a roughly equal-powered fender and marshall (which you have), I would expect the fender to have a lot more punch and dynamics, and the marshall to have a thicker, fizzier, more saturated sound, even on "clean" sounds (Marshall doesn't really "do" clean). Given a 100W Marshall and a 100W fender with two guitar players both playing the same part, I would expect to hear the "punch" coming from the fender and the "fuzz" coming from the Marshall (this is an awesome sound, by the way).

Good luck, either way.

Cheers.