Building a replica 20 watt lead & bass

[Matthews Guitars]

Just for the fun of it, and because I have examples to work from, I'm building a replica of the 2061 Lead & Bass 20.

I'm having the original 2061 chassis copied, mostly, but making the back panel in the configuration of the 2061X hand wired reissue, which moves the impedance selector to the back panel.

I've got the chassis being made at the local sheet metal shop, from drawings and dimensions taken from the original amps. (Both the 2061 and the 2061X)

I'll be able to have more made if there's a demand for them.

I've had correct transformers for it in hand for a while now. Using a Heyboer 18/20 watt OT, and the Marshall original PT.

The hard to source three green vitreous 5 and 25 watt resistors, I was able to order from Marshall.

Building this with Iskra NOS resistors, and with NOS Mustard caps or Vishay MKT1813 series (previously ERO brand) film caps.

One change I'm considering: The original has the 68K grid resistors for both channels (4 resistors) wired into the wiring harness, and not on the turret board.
Since I'm making the turret board from scratch, using 1/8" phenolic, I have the option of simply adding those resistors to a modified, slightly lengthened version
of the original board. Should I do that?

I like the idea of simplifying the wiring harness.

 

[NickKUK]

I think radio interference is a far larger issue nowadays than in the 60s/70s.. so I'd be tempted to move the grid stoppers as close to the grids as possible. I put a 47pF silver mica cap to ground to provide an RF return path.

All depends - if you're going all out replica then no. If you're wanting something playable whilst gigging widely then some sensibilities may need to be added/adjusted.

 

[stickyfinger]

Why use NOS? Weren't you they guy preaching about how we need to save these for restorations and how new parts were superior and more reliable?