Here's a gut shot of the amp.

Here's my completed build.

It's a 50w OTS I built from a kit.
For transformers, I used Hammond bassman type replacements (PT 291DEX, OT 1760L, Choke 194B).
I had to drill some new mounting holes for these, but it wasn't too difficult.
I also went for the 'heater wires in the air' approach.
For tubes, I used some old Mullard ECC83s in V1 / V2, a new Tungsol in V3 and TAD 6L6s in V4 / V5.

My voltages were a touch high initially (477V at power tube plates, ~200V at V1 plates), so I increased the 3K3 dropper resistor to 4k7.
This got the preamp plate voltages down a touch, so I ended up with ~190V at V1 plates.
I also adjusted the PI trimmer for a 6V difference at the V3 plates.

I didn't build the head cab, I got that from Tube Town.
I had to drill the mounting holes in the cab, but again that wasn't too difficult once I'd made a paper template of the chassis.

I'm really pleased with the sound of the amp. It sounds really full bodied with the 2x12 cab I have.
I'll probably invest in a G1265 loaded cab and a C-Lator eventually.

Looks great!

What Zilla cab / speaker have you got there, and how does it sound good?

I ordered my OTS kit without transformers. I will be using a Hammond 291DEX PT, and Nik said it'd be fine to use the 5v tap for the relays. The Hammond isn't a drop in replacement though (nor are the Hammond choke and OT that I'll be using), so I had to drill new mounting holes.

Yes it was quite easy with the Dremel.

Hi all,

Firstly let me introduce myself. I have just received my OTS 50 kit which will be my 3rd amp build. The 1st was a champ clone, and the 2nd was an Ceriatone Expression with some tweaked components. I'm really looking forward to building the OTS.

I can confirm that the chassis is powder coated on the inside and out, and is white in colour. It looks great! Also Nik told me that they switched to steel from aluminium for more strength.

See attached a couple of pics. The chassis already has some studs for grounding, but Nik told me to scrape away the powder coat in a few locations to ensure a good ground connection. These were (snippets from Nik):

The hole for volume pot
The hole for bright switch
The hole for treble pot
The hole for the DIN socket
For the 1st preamp tube, it'd be good if you burr the screw holes too (I've still got to do this)

He suggested that it might be a good idea doing all of the pot holes, but in the end I just took the simplistic approach and deburred any holes where the controls had something metallic that the user could touch such as pots and switches.

You will see from the pictures that I got a bit excited with the dremel , and Nik said you only really need to deburr a little bit.

Hope this helps.

Rick