Marshall JTM 30

[chad_svt]

I finally got my marshall jtm 30 today it had been in the repair shop waithing on a part. I was wondering what tubes should go in it. I'm really into that AC/DC, crunchy riff rock type stuff but also with nice cleans. Also when i mentioned buying it some people (Jeff H i think) mentioned a really easy mod for it. Just wondering what those were. Also are the power tubes supposed to be 6L6's because mine are. Thanks so much and suggest away. It has a celestion 16 ohm G12 speaker in it, is this what it needs or should i get a new one and if so which one. Thanks

[Jeff_H]

Re: Marshall JTM 30

Chad....

Sorry, I just saw this thread. The power tubes should be EL34's, I'm somewhat confused if your JTM has 6L6's - perhaps someone modded it, or maybe my knowledge is not what it should be.

If you're looking for classic Marshall tone, you'll need EL34's for your power tubes. I like Svetlana power tubes and EH for the modern procuction stuff. JJ's are good as well. As for pre-amp tubes, there are a ton of options. A lot of people really like the JJ 12AX7's. They tend to smooth things out nicely. I've had EH 12AX7's, JJ's, Mesa's, Sovteks....I like the EH's and JJ's the best. The new GT 12AX7-M is supposed to be one of the best pre-amp tubes out there. A direct copy of the famous Mullard. I prefer NOS pre-amp tubes, but you'll pay anwhere from $30-$100 per tube.

As for the mod, do you have a parallel effects loop? If so, there will be a knob on the front of your amp to control the level of the parallel loop. On the back of your amp, there will be an "in" and an "out" for the parallel loop. Stick a small patch cord (the kind you would use to connect 2 pedals) in the loop. Then you can use the parallel knob on the front for an extra gain stage. Pretty cool.

The stock speaker is probably ok, but not the best. I would get the tubes sorted out first. Worry about the speaker later. A vintage 30, or one of the Eminence line of speakers will make a nice difference.

Hope the info helps you a little.

[Gearjoneser]

Re: Marshall JTM 30

Yeah, I though those had EL-34's too. Contact a Marshall service center and ask them. In that particular amp, if it were mine, I'd put JJ EL-34's, GT 12AX7C's, and a Celestion Vintage 30 speaker in it, make sure it's biased perfectly, and enjoy!

[Simon_F]

Re: Marshall JTM 30

I think 6L6s are right for the JTM30. The JTM60s have a pair of EL34s, but remember the JTM30 is a 30 watt amp.

I have an old Marshall catalogue upstairs with the JTM30 specs including power tubes, but I can't fetch it right now - Mrs F is asleep. Sshhhhh!

[Simon_F]

Re: Marshall JTM 30

Checked the old Marshall catalogue today - the JTM30s had 5881 power tubes, which is the European name for 6L6s. So you're OK!

The JTM30s only have a series effects loop so you can't do the gain trick with the parallel effects loop that Jeff mentioned. However, being a 30 watt amp, you can crank it more for power tube distortion.

I've been thinking about buying a JTM30 myself - great little amp for small gig rock and blues.

[chad_svt]

Re: Marshall JTM 30

Thanks so much for all the info. You guys are always a huge help. Cant wait to get the thing screaming at its best.