Marshall JTM60?

[TBR623]

I had one too...I was very disappointed. I spent more time trying to find ANYTHING that sounded good.Chainsaw distortion-IMO,its not a good example of Marshall amplification.Sold it for $250 and was happy.

 

[59Vampire]

i had the jtm 312 which had 5881s converted it to el34s and NEVER had an issue, the clean channel roared! it sounded killer with a ts808. it was a good one i guess. ended up selling it to the Zendrive creator when i had my 18 watt built.

 

[Kage]

The clean channel was nice, but to get it clean you had to turn the master down and then you couldn't get the channel volumes balanced.

Interesting, my experience has been the opposite. When I was running the channel volumes up around 12 o'clock and the master the same I was finding the clean channel breaking up a lot. Since I've starting running the master up past 3 o'clock with the channels down around 9 I've found the clean channel to run much cleaner than before with more overall volume. Certainly not Fender clean but it doesn't seem to break up as much this way.

 

[dwagar]

an old thread, but that's what happens when you procrastinate as much as I do. The old JTM60 finally came up on the 'what can I mess with now' list.

LP20th, fantastic mod man. Your pic over on the Metro forum was exactly what I needed.

Cutting the diodes out makes this amp sound great IMO. I've only tried it at house volumes so far, but I'll drag it over to a practice one of these days and crank it up. I always hated the buzz saw on the gain channel.

Again, thanks!

 

[keef]

Never played one of these, but I recall a big amp shoot out in GP where the JTM 60 was among the winners. The 602 had a great review in Guitarist magazine. Now I read about decent or even sucky tone.

I hear ya - ads bought by Marshall...?

 

[Dega500]

Hey guys,

How about a link to the pic on the "Metro Forum"?

I've been interested in trying that mod for years.

Thanks,

Mike

 

[Kage]

I don't think it has sucky tone. Mostly just a matter of taste.

 

[zombiwoof]

When you remove the clipping diodes on a Marshall that has them, do you have to do other circuit mods to compensate for their removal? Do you still have overdrive when you choose the lead mode?

Al

 

[lp20th]

With this mod you add a resistor in place of the diodes. This completes the feedback loop. One other point, it appears there were two versions of the clipping diode circuit in the JTM60 from the schematics I have seen. The first, like mine, has the diodes feeding back to the previous tube stage and the 2nd where the diodes are tied to ground. The mod I did adding the resistor applies to the feedback version.

You still have overdrive with this mod, not nearly as much, but its all tube overdrive.

Here is the link. Look for my user name and you will see an attached image.

http://forum.metroamp.com/viewtopic.php?f=4&t=13499&p=235196&hilit=jtm60#p235196

lp20th