My first turret board design : opinions needed !

[ricothetroll]

Hi,

I plan to gut my disliked Fender Hot Rod Deluxe to convert it to a Vox AC15 ! As it will be the first time I build a tube amp from scratch and on a turret board, I would like to have some opinions about my design (what could be improved, what I forgot to consider, etc)

Here is the schematic of the Fender :
http://www.blueguitar.org/new/schem/fender/hotrod_deluxe.pdf

And the Vox :
http://www.blueguitar.org/new/schem/vox/ac15htvh1_handwired.pdf (schem on page 4)

Here is my turret board, drawn on DIY Layout Creator :
https://dl.dropbox.com/u/28610725/Turret%20Board%20v2.pdf

As I wanted to keep the transformers, the choke, and avoid drilling igly holes in the enclosure, I had to adapt the Vox shematic :

- I used silicon diodes for the rectifier. I kept the Fender design for it and added a series resistor to get some voltage sag out of it.

- As the Fender trafo is 325-325 instead of the 300-0-300 expected in the Vox, I dropped some voltage through two 1N5364B zener diodes in parallel (33V). I've seen this trick in the TAD Tonebone 6L6GC to EL84 adapter. The EL84 are over voltaged, but that's the way the AC15 is designed (about 370V on the plate at idle...)

- The filter caps in the PSU are MKP polypropylene. Those weren't too expensive so I replaced the electrolytics by those.

- The output tubes are not supplied by the choke because the Fender one is only rated for 50mA, that's not enough for the 100mA of the EL84 in the Vox circuit.

- I replaced the EF86 pentode circuit by the first half of th 12AX7 normally used in the Brilliant circuit, as it's done in some AC30s. I decided to do it after reading Merlin's book and to avoid microphony problems.

- I added a master volume pot, as implemented in the latest AC15 designs.

- I removed the "low" input jack, as I do not plan tu use it and as I don't want to drill holes in the enclosure.

- I will later implement a reverb driver/return circuit (with transistors/opamps)

Any comment on my circuit would be fine !

Thanx in advance.

Best regards.

Eric