18W-36W TMB Reference Boards

[crgfrench]

I've been designing some PCBs for 18W and 36W builds, here is a summary of progress so far:

1) Fullerwell 36 “super eyelet board”, includes split ground bus and power rail.
2) v1.0, adds footprints & traces, output grid stop resistors
3) v1.1, optimizes pin spacings, thru-hole diameters, and mounting hole diameters.
4) v1.2, adds optional EF86 input tube capability, adds optional noise reduction circuit (the “Paul Ruby mod”), adds selectable global single star ground/split ground bus, adds switchable output tube pentode/triode operational modes.
5) v1.3, adds on-board diode rectification option, reservoir cap and filter cap, deletes HV fuse mounting location.

Here is a photo of the five designs:

18W-36W TMB REF VERSIONS.png

I have three v1.2 boards available I'd like to give away to 18Watt.com members who would like to build an amp. If anyone would like one, please let me know in the comments below, or email me at crgfrenchATgmail.com, and I'll send you one (if more than 3 folks inquire, I'll choose randomly). These are prototype boards, so I'm looking for feedback from builders. There are some v1.1 boards out in the wild, in the US and Australia. This series of boards grew out of my 36W Fullerwell turret board design. The boards are very high quality, 2mm Kingboard FR4, with 2oz copper with 5.1mm wide traces equivalent to 20 AWG. The thru-holes are gold plated ENIG with a 2u" gold layer over nickel over the copper. The solder mask is halogen-free Taiyo PSR2000 Eclipse.

Here is a photo of v.1.0, v1.1 and v1.2 boards, the first two are populated and the bare one - v1.2 - is what I am giving away to qualified builders here.

18W-36W TMB REF v1.0-1.2.JPG

I have a builder's guide available at https://drive.google.com/file/d/1qmA9wT ... sp=sharing
I'll try and upload this PDF into the "Downloads" section as well for anyone interested.

The boards are 13" x 3.125" x 0.08". They support 18W builds with 3 12AX7s, 2 EL84s and a EZ81; also, 36W builds with 3 12AX7s, 4 EL84s and a GZ34. You can also add an EF86 input tube to either build if you want. You can run the output tubes in Pentode mode or switch to Triode mode. The 36W circuit also supports a half power-switch that cuts out 2 of the EL84s. This board, v1.2, does not include an on-board diode rectifier circuit or reservoir cap, so the builds would be similar to a traditional 18W or 36W build, with chassis-mounted rectifier & can cap. The board does support the Ruby mod if you want to add that.

Finally, if anyone wants to do their build in a Ceriatone 36W chassis but using Heyboer iron, I have some 3mm aluminum adapters available for that combination (requires some drilling/filing of the chassis).

I'd love to see a video or at least pix of your builds, and hopefully vids of the final amps in action! Please only inquire if you're an experienced builder, these are not full-blown kits with explicit wiring instructions and although I'm happy to chat via email, I'll be unable to walk a new builder through a complete build just due to my own personal time constraints.

Thanks in advance!

[Bieworm]

Jow Craig! Nice stuff!
How did that EVH painted amp turn out, by the way?

[crgfrench]

Jow Craig! Nice stuff!
How did that EVH painted amp turn out, by the way?

Thanks! The EVH build got back-burnered due to 36W customer builds. Still sitting patiently in the back of the shop. Thanks for reminding me about it. That one has a Ceriatone power transformer which ended up being slightly too physically large to fit the 1x12 cab, it hits the speaker magnet; so I need to sort that out too.