Got everything required, except the case.  Was thinking, that as I am building a modular unit, I might have to use something like 19" rack cases

Did a stock check of the parts required, off to Jaycar tomorrow to buy a couple of resistors and a few hardware bits and pieces.  Hopefully come Monday afternoon will have a working PS.  Not boxed up but a working PS, none the less.

With 256V in and the voltage divider of 100k and 220k resistors, should give an elevated voltage of approx 80v.   :dbtu:   Hopefully, with this set up, providing I get the hardware wiring right, this should be a fairly quiet supply. Ideas initially taken from audiophile circuits.

Re-did the power supply.  Powered by the 16V AC wall wart and then transformed back to 256V, however, will be using 6.3V, elevated heaters to recuce hum etc.   Updated circuit now attached.

Will definitely have a look at the microphone screw ring connectors and sockets, good idea that.  Won't take much to rewire the tip of the AC wall wart.  Have got a lot of the components already, will have to see what else I need including the hardware.  Getting the PS operarational might be a project for the Easter weekend.

Only talking about the PS for the one 12AX7 tube in the preamp, 20W should be plenty, shouldn't it?
From my reckoning (and I am probably wrong :-) )
Heaters 12.6V @ 0.15A gives approx, 2W.
Less than 1mA on each plate, call it 0.5W combined.  Even at 25% efficiency in second transformer should be enough, shouldn't it?

I've just seen a nifty idea on one of the audio forums.  I can get a 16V, 1.25A AC wall wart and use this as the mains input, step down transformer.  I went rummaging through the junk box and found a transformer that had 2 x 15V, 0.67A secondaries.  I'll parallel the secondaries and use them for the step up transformer.  Voila 256V out.  I'll use 2 x 2A bridges for the HT and heaters and an LM317 for 12.6V out.  Preamp PS done using a simple wall wart and a 2.1mm socket for the mains input.

Made the additions of the 2 x bleeder resistors and the neon lamp.  New schematic attached.
Cheers Chris

I hold what was the limited license VK3TUB, which was the frequencies above 50MHz, I was interested in mainly 6 and 2 metre bands and 70cm, but when they did away with the Morse code requirements, I got into homebrewing for the 80 and 40 metre bands.

I'm in Narre Warren on SE side of Melb.

Rightho, so bridge, then 220uF cap, then bleeder of 270k to 330k and neon in parallel to them, then 100 ohm resistor with standby switch in series, then another bleeder of 270k to 330k to gnd.  I'll redraw and post, to ensure that I've got it right. 
Cheers Chris.

Hi Everyone, thanks for the words of welcome.

@Enzo
Yes everything from the US uses an 'inverted' input down under...lol

@phatt
As you said I think that modular is the way to go.  I think that it helps with the trouble shooting.  I have an amateur radio background and nothing worse than getting to the end of a project and you have to debug it from the beginning.  I learned early on that it is much better to get one section working before moving onto the next.  I was thinking modular too, from the point that, I have other pieces of equipment around the house for instance an SS Sansui audio amp, some SS guitar amps, SS preamps and it would be good to develop each of the valve pieces independently and see how they affect the sound/performance of the other items.  Also would be good to build something like the real spring reverb unit and then be able to use it with other amps etc

@Roly,
Yes I am familiar with the Lamington but hadn't seen the Lamington II.  Have been around the ozvalveamps and AX84 sites, so have seen various schematics but must have  missed the 50W version. 

Thanks for your helpful hints with respect to my circuit.  It is quite developed. I have been piecing the design together for about five years.  As I've done further reading and gained better understanding or seen a design feature I've liked, the circuit has been modified.

I agree totally with your statement about the back-to-back HT transformers. Originally, I was going to use this configuration for the whole amplifier (which was far simpler), as it only had to deliver power to 1 x 12AX7 and 2 x 12AQ5.  So about 600mA in heaters/filaments and then about 95mA max signal current.  So not really an issue for these transformers.  However, I have now added the second 12AX7 for the reverb unit and I was thinking of adding a 5879 pentode for overdrive, so these transformers will not be sufficient.

You are right about them getting thin on the ground though.  I bought mine for $7 for the pair when Dick Smith's got rid of all there components and became a computer/audio equipment store. 

I was going to maintain this back-to-back PS config, purely for the preamp stage.  As part of the modular design concept I will include separate power supplies, one for each of the PA, the tube reverb and tube overdrive sections, this may be overkill but each modular piece can be completely stand alone (including power supply and enclosure/housing) so that I can chop and change and use them with other gear.  I will probably put together the Lamington type supply for the PA.

In regards to the input, I don't always use stomps but I do sometimes use the Behringer GDI21 which is a DI/amp modeller.  Because I don't always use that would you suggest that for a simple improvement, I change that 100K pot to 1M?

The 12AQ5 are probably not the best output tube but i thought that they would give me about 10W for a nice practice amp and seeing I had them laying about, I thought, why not?   The M1120 was used to give 16K at primary for 8ohm speaker.  This would reduce the output somewhat as the 12AQ5 requires a load resistance of about 12K in PP config.  This was taken into account when doing the biasing calcs etc.  The M1115 and M1120 are a good value option, seeing that things like the Hammond OPTs are so expensive.

I can change the position of the standby switch.  I will put it in after the 100R resistor.

The bleeder resistor, put it in parallel with the 220uF or at the end of the filter chain?  Something like 150K/2W? Take about 5 seconds for V to drop from about 240V to 30V on the 220uF.

The 47R/10W across the secondary of the OPT is not a problem.  That's easily done.

Cheers Chris

Hi
Just thought it was time to introduce myself.
My name is Chris but everyone calls me Nodz.
Been lurking around various guitar/amp and hifi/diy audio forums for a while.
Have four guitars (3 electrics and one acoustic) and two SS practice amps.
Have made some SS and valve audio equipment, thought is was about time I started skimming around the net and try and design my own guitar amp.
So after a bit of reading, designing, redesigning, borrowing circuits from others I've come up with the attached.
Due to constraints both time and financial, will probably build amp in modular fashion, that is step 1) preamp, 2) stand alone reverb 3) then the PA. 
Possibly will include an overdrive section but the idea is to have an organic modular amplifier, that can be altered as I go along so if I don't like certain developments, I can revert back to the previous state if desired.
I also haven't decided on the final PA.  At the moment, it uses a couple of PP 12AQ5 (just because that's what I found in my junk box) but I may use LM3875 and have 2 x 50W output channels, 2 x 6L6 (50W) or 4 x 6L6 (100W).  I just haven't established what kind of O/P I require yet.
Cheers
Nodz