SL-1200 DC Power Supply DIY

[Ianmac]

Khom
Ive now finished building my phono pre so I can concentrate on the PSU for a few days before I start another batch of bearings.
I am working along the same lines as you with IC302, IC301 and AN6680 so will turn my attention towards the FG Amp. Im interested in the spectrum you noted from the FG, it must be telling something about a rotational issue.
If you get a chance, try a deliberate unbalance of the platter and see what spectrum appears. Im still looking for a platter, at the right price, to mod so I can freely scope the electronics with the motor running.
My initial reaction is to simply remove R221 and replace the C216 end with a 9v reg supplied from my clean 21 v supply driving the control electronics. It is also my intention to reduce the physical size of my sub regs to make them all on board additions with, where possible, pin outs that match the holes vacated by redundant components. 1mm and 1.2mm vero pins are usefull to help achieve this.
The reg I need for the FG amp is almost identical to the one I use for IC 301(9.6v). I am using LT3082's for all my sub regs. This is in an SOT223 package and can easily be fitted and soldered onto 0.1" Vero board with the track removed under the 223 to stop P1 (set) and P3 ( In) shorting onto the output tab (also P2 Out) which is 3.2mm wide. Dependant on the techie components I can reuse I should get down to one or two resistors and one small C + the 3082, so the size could be quite small.
I'll keep you posted as to progress.[IMG][/IMG][IMG] Underside of sub reg board with two 3082 regulators[/IMG] Topside of sub reg board for two regulators.

To help those not too confident with electronics, if I can find time, Ill revist the possibility of an updated version of - 1.replacing the stock transformer with an external transformer rectifier box,- 2. Replace the Techie regulator , -3 adding a second regulator to split feed the Control and Power electronics (which will involve cutting one track on the PCB). Beyond that, using the sub regs Khom and I are talking about you will need to be happy with what you were attempting.

This raises the question as to whether anyone has tried using an SMPS supply which, using an off the shelf unit, makes replacing the stock Transformer a relatively simple task.
I am wary of noise/ transients etc emanating from some SMPS designs and how difficult these are to get rid off as they pass right through most regulators. It would need a carefull choice of supply.
Ill have a look at what Farnell and RS have to offer. I say SMPS since last I looked, off the shelf linear supplies were thin on the ground.

Any one tried an SMPS ( Switched mode Power Supply)