MJW Amps Roadstar Conversion

martinw

I thought this might be interesting enough for a thread, as it's something that comes up in conversation now and then. Also it was done for a Fretboard member @ChrisP86

What do you do if you get a custom built amp which you can't try first, and the sound is not quite to your liking?

Firstly, buying a custom built amp is something that I would only recommend to more experienced players if you're going 'off-piste' with the design, so you can have a good idea of what certain valve types and architectures sound like. In other cases the demo videos on my YouTube channel will help, and discussions with the builder can ensure you end up with the right amp, which happens in virtually all cases.

Obviously the resale values on custom stuff is not as solid as a well-known brand, but my response is that a hand-built amp is infinitely modifiable, and personally I offer a free adjustment/re-voice/tone-tweak with my amps. I can only think of one or two occasions where I've been taken up on that, and it covers more minor stuff: a bit brighter/darker, a bit more/less gain, that type of thing.

But in rare cases, an amp can be completely rebuilt as something else. Chris bought this Roadstar 36 second hand, and fancied something a bit different. After some discussion, he decided to take the plunge, and I'm grateful he did, as it's turned into a fantastic sounding amp that I may not have arrived at without the motivation of a paying customer!

He basically wanted a Marshall preamp putting into the Roadstar (which as standard has the simple Watkins/1974-ish preamp with just volume and tone), besides which he decided to add dual master volumes (on a footswitch) and Power Scaling. As the design then resembles my V6-20, and I had a front panel designed ready, that's what it's called, although it has a few differences.

It has Bright and Normal gains (reflecting a jumpered 4-hole Marshall), but also has a 'decade' boost switch, which reconfigures from JMP to JCM by adding a gain stage. The PI is AC30, and the presence is actually a Vox Cut control, as the amp has no negative feedback.

It sounds fantastic, and I have to think now about making this a standard design in my range. Hope you like it Chris!

Adam_MD

That looks excellent and freakishly tidy 

CHrisP86

Can't wait to get this tomorrow and crank it up!

Looks fantastic too!

Thanks Martin.

ThePrettyDamned

This is why I'd absolutely *love* to commission you for a build.

Your v6-20 with master, power scaling and a fendery voice would be immensely tempting to me... And is the primary reason I don't own a Princeton 68 custom.

martinw

Thanks

photek

Fantastic. I will at some point do the same. Having the custom options makes a marked difference as there is always for me at least some missing and some pointless features in production amps. Nice work Martin.

eventhelosers

Excellent work Martin! Quick video demo????

martinw

 

photek said:

Fantastic. I will at some point do the same. Having the custom options makes a marked difference as there is always for me at least some missing and some pointless features in production amps. Nice work Martin.

Thanks

eventhelosers said:

Excellent work Martin! Quick video demo????

Cheers Phil. Didn't get time for a demo unfortunately, and it's owner should have it back today. Maybe @ChrisP86 can do one?

CHrisP86

A demo of some sort is on my to do list (as long as I can actually get a good recording out of rubbish recording equipment and my sloppy playing!)