What shall we build?

paulnb57 · June 2018

Sounds good to me!

normula1 · June 2018

And to me.

sweepy · June 2018

I’d go very minimal, imagine a 50w Fender Champ

mr-mac · June 2018

How about a selmer trebble n bass 50 but with some tweaks to make it more useable at lower volumes and maybe a 2nd channel with some more gain.

mr-mac · June 2018

RiftAmps said:

Ok guys, thanks for all of your suggestions so far.

I'm really enthused by the non-Marshall ideas, especially the HiWatt and Vox stuff. I mean, is another modded-Plexi type really needed when we have the opportunity to do something different?!

I think that's the route we'll go down, it's certainly got me really excited about this project.

So, preliminary specs are:

Single channel Hot-rodded Vox-inspired preamp section with Gain, Treble, Mid, Bass, Master, and Presence(or Cut?) controls
Hiwatt style 50w OP section, with switchable GZ34/SS rectification
Series FX Loop with level control
Some form of outrageous boost to melt faces
I'm going to start the circuit design shortly

How about a midrange control on a lead boost... To allow cut or boost mids for solo to either give it a scooped or fatter sound???

paulnb57 · June 2018

Would it be possible to make it variable power output?

RiftAmps · June 2018

paulnb57 said:

Would it be possible to make it variable power output?

We could I suppose, but each option also has drawbacks.

For example, a half-power switch (pentode/triode) results in only a 30% volume drop, which is never enough and nearly always results in a degradation in tone, something which is a no-no in my book.

Powerscaling never works as well as you hope for, it always adds fizz, and suppresses those lovely top-end harmonics that you spend so long dialling in. Seems counter productive to me.

The most effective form of power reduction is a simple MV control, which we have

sweepy · June 2018

Agree 100% on Power Scaling, I’ve never found one that works convincingly

PhilKing · June 2018

I'd add another vote for something around the original Selmer Treble & Bass. They have a really lovely sound when you drive them a bit, so upping the preamp gain on one channel would give a really useful sound and having the channels switchable would give you the nice clean sound (which could be an EF86 (or 6BR7) valve, to give that Voxy tone. Though if you were really going for an interesting second channel, something around the 6SN7 would be really cool too.

RiftAmps · July 2018

OK, managed to find some spare time to make progress on the build.

I started off by drawing a few simple lifesize board layouts on paper, this one is the final 'clean' version that I'm happy with

Image: https://s8.postimg.cc/r3bcueyqd/RFT03821.jpg

I find 'perf' board really easy to work with for custom-builds/prototypes, here's a sexy little blue number supplied by our good friends at @Modulus_Amps. The holes are 2.5mm in diameter so will need enlarging to 3.2mm to accept the eyelet terminals

Image: https://s8.postimg.cc/l2dnxgepx/RFT03822.jpg

I use masking tape to cover the topside, then punch through with a pencil to mark which holes need enlarging

Image: https://s8.postimg.cc/l2dnxhwqd/RFT03823.jpg

Then it's over to the drill press to drill them out

Image: https://s8.postimg.cc/po9s5upz9/RFT03825.jpg

Once that's done, I remove the masking tape and press the terminals into the board using an eyelet tool in the chuck of my drill press. The piece of Bubinga underneath provides enough back pressure to allow the eyelet to seat properly without being squashed