critique request - draft PCB for MILA tube pre

andrew_k,

oddly enough, your preamp is coming up almost exactly the way I built it, with even the same kind of input transformer impedance switch! although mine is a different transformer. I built the pad and impedance switch in a little veroboard module with two DPDT relays. the relays are probably useless but I get paranoid about too long high impedance wires in a rats nest like any turret board will become.

a little tip about the thick bus wire, if you're using solid copper like I did, and through-hole turrets, turret holes will become a bit small. but you can stitch the wire in. Basically, every second link between bus connections goes above the board, then though the hole, and next one under the board. repeat.

Thanks Kingston for posting your layout. Hopefully my turret board is long enough. I’m getting a toroid made for two channels and am not sure what would be best in terms of low noise and cross talk etc. Would a single secondary 250V 50mA to a single power supply, or 2 x 250V 25mA to their own PSU’s be better. Plus the 6.3V, is ac or dc best. I know ac would be easier.
Any help is appreciated.

Are you getting toroids wound in Aus? Care to share info? 

Hi Andrew
No Problem. I've used Harbuch before and think there great. It's a bit more expensive than Americans are paying for the STANCOR PS-8416, but for us it's much the same. Cheaper than Hammond. I think maybe I'll change it to just 1 x 250V @ 50mA though. maybe we could get a discount for 2?
price of $105.90 + $35.00(Design &
Engineering) + $13.00-Freight + GST.

Primary 230V 50va
secondary1 250V @25mA
secondary2 250V @25mA
secondary3  6.3V @2A
secondary4 42V  @50mA
Cheers
Simon
Peter Terlich
Manager/Director
Harbuch Electronics
[email protected]

Thanks for the info, and the offer. I already have my traffo's for this build -- a 12+12 30VA and a 15+15 30VA for AU$30 each from Altronics. I'm using the G9 psu for my dual MILA.

Sorry to revive an old thread but I am curious about a few things if you can remember.
1.what in/out tranfos where used for this build?
2. What power tranfos where used?
3. What did you use for 48v?

Thanks,
-Alain