Which Marshall Amp Should I Buy??

Hi i am about to buy a new marshall amp. Im planning to spend about $1200 Australian dollars(about 400 Pounds)new or second hand. I am into Metallica sort of stuff and looking for an amp that has a fair

bit of distortion and gain for heavy stuff and lead. I have been offerd a JCM600 twin 2x12 for $1200 Aust. Is this a good amp? If not why not? also i am considering a valvestate AVT2000(new) for the same price. What other amps do u suggest? i am in a band and need the power to match drums easily. But also want to use it in my bedroom a lot

of the time. Any thoughts would be greatly appreciated. Regards

hi there shaun -

the jcm600 is a pretty decent amp and 400 quid for a 60w twin channel 2x12 combo is not bad going. this isn't the bargain of the year, but it's a sound deal. and it's fairly new, so hopefully it'll be quite reliable - although with valve amps you can never be sure of anything.

i don't know how you'll go with the super-high gain, scooped metallica sounds though. these marshalls have a more 'classic' rock sound. there were some very high gain jcm900s available (eg the SLX), but i'm pretty sure the gain on the jcm600s wasn't as saturated.

have you tried it? as with all amps, you REALLY should try it before you make a decision. you'll soon know whether or not you can get the sounds you want.

on the positive side - this amp should be pretty much perfect for jamming with a full band. a 2x12 combo gives you a nice 'spread' and 60W should let you cut through no matter what style you're playing. the JCM600s also have a speaker emulated output, which could be useful for your bedroom jamming. it's designed to give you an approximation to a 4x12 cabinet at line level.

JCM800 single channel (2203) is the amp for classic rock. 100% valve signal path. The JCM800 twin channel is solid state distortion. As are JCM900's, the entire pre-amp is solid state, but valve output stage (if it's that important to you).

Thew main difference between the above is the better sounding 'asymmetric distortion of the valve circuitry... gives that nice 'grumbly' distortion tone when you back off the volume guitar's control.

The solid state distortion is symetrical... which means it goes suddenly into distortion. Not a problem though, if you just want outright distortion mayhem. For blues and subtle stuff - yuk! Solid state can be designed to do the aymmetric stuff... but no one's done it yet for some strange reason (except us at Session).

Have not seen a JCM600 to comment on yet. Don't touch the JCM60 models, they are a disaster waiting to happen. Loadza computer style connector/jumper cables, flimsey chassis, get very hot, basic (school project) design solid state distortion... just naff generally.

Watch out for Marshall comno cab's. They are often only 12mm (1/2' thick MDF! This means they are quite weak at the corners where the big 25mm (1' radius means that the corner joint is only about 5mm thick with no internal bracing!!!!

Sorry, I work with this stuff every day and am therefore, objective. I certainly hope that Marshall pull their socks up and start producing decent stuff again soon.

Ikutaro Kakehashi (Roland and Boss founder) claims first use of asymmetrical s/s distortion on the Boss OD1 pedal (Power On [Roland publication], issue 7, Summer 2002) but I don't know when the OD1 dates from. I suspect the HH Valvesound might use it too, but it's 'distortion' circuitry is in a potted module, so not easy to examine. It should show up by inputting a sine wave and checking the waveform on an oscilloscope though.

That's interesting, OD1s are still fairly common and I have had use of them from time to time, but can't recollect seeing asymmetric distortion on the output (I usually put anything I have through the workshop on my oscilloscope for checking out!). The Ibanez 'Tube Screamer' is definately not asymmetric - surprisingly.

The one thing that lets FX pedals down is that most (they all basically copy the Roland idea and mistakes) have an input impedance of around 100k ohms... a tad too low for guitar. Especially when you have several in line and set to by-pass. The by-pass switching only switches the output jack to the input jack, leaving the input circuitry still connected. Therefore, the build up of parallel low input impedances spoils the guitars tone and dynamics.

There's not likely to be anything ground breaking about the HH (as with anything). As long as you can see the output waveform, it's possible to re-create the circuitry pretty much. It's really the thinking behind the circuitry that's king in guitar related electronics - *not* the technology used. Take computers... they're brilliant as long as you have good software. There are good and bad software designers though. Sadly, given the power of the brand and the marketing budget, much mediocre product sells better than similarly priced great stuff.

Same with guitar electronics. Take the numerous digital Modelling/FX processors with state of the art electronics that are let down by the software, and still sell in bucket loads!

The Tube screamer is just a symmetrical bridge. There's a couple of schematics for it floating around the net. It was the Tube Screamers ability to overdrive the front end of a valve amp that really made it. It's own distortion was pretty horrible.

First assymetric bridge I can recall seeing was a Hiwatt L100R which was made towards the end of Hiwatt's original incarnation. There may be earlier examples though. That was, I think ~1980.

The only early one I can find independent reference to, for asymetrical clipping, is the Fuzz Face in the 'Voltage feedback/biased bipolar - Germanium' class, but it's only some of them.

That's probably one of the reasons for 'true-bypass' switches becoming more popular as additions, apart from the failsafe aspect if any of your pedals suffer an electrical failure.

I think with the HH there's a separate compression stage involved, and I think it includes the reverb. I can hear the reverb tail build as the note dies, the same as if you post compress a recording which already has a long reverb tail.

That means the valve's distortion (in class A) is asymmetrical. I wondered why it was popular.

You can say that again. Yuk. Double Yuk even!

I jammed last night with my 'experimenting-on' Sessionette amp in which I have installed a 'distortion style' three way selector switch. Position one is symetrical 1:1 (very compressed HM sound), two is asymmetrical 2:1 ratio (grumbly/bluesy) and three is 3:1 ratio, three was the dogs doolies for blues. That's for sure.

In my head as I was playing, I could see the oscilloscope trace of an HT starved ECC83 driven to the limits! And all done with solid state... juicy! I might try 4:1 next, but expect it to be 'A Bridge Too Far?'