WAD Phono2 power supply.

[pre65]

My philosophy is use what you have (if it's at all suitable), and you could pad down 12.6v a bit with resistance.

Try redesigning the circuit to suit what you have, there is help if you need it.

[pre65]

Shane, I'll have a look in my spares box to see if I can help with any bits for you.

[shane]

Try redesigning the circuit to suit what you have, there is help if you need it.

That's why I was asking why Nick used two transformers.

From what I've gathered about Nick over the years, he doesn't usually do anything without a good reason, although it maybe that he simply had a good supply of cheap 9v transformers in 2003.

Offer of spares much appreciated!

[Nick]

I built it first with a 240v + 9v TX from Maplin, it created too much hum field. Using the two back to back toroids worked better.

My philosophy is use what you have (if it's at all suitable), and you could pad down 12.6v a bit with resistance.

Yep, but I find that leads to poor results and either a failure, or more cost in the future. But that's a different philosophy. Designing around what you have is one thing, but taking a working design and replacing parts runs the risk of making it into a non working design. Its one of the reasons why I stopped posting circuits. I got fed up with doing other peoples work for them.

Using 260v instead of 230v means that the CCS will dissipate more heat, so make sure its got enough heat sinking. Likewise using a 12.6v TX will mean the heater supply is seeing 17.5v, so the regulator is dropping 11v, so with three ecc83's thats 10W its got to get rid of. rather than 6W starting with 9v. And yes you can burn it off as heat, but most of the time we work at getting low impedance power supplies.

Two 60va 9v transformers are £38.30 from Rapid, less than a purpose would transformer.

[shane]

Makes sense to me.

One Analogmetric toroid now heading for eBay....

[pre65]

Of course you are right Nick, no question about that.

But poor (literally) Shane has little spare income.

So far Shane, I've found for you

1 x WD choke 15H
3 x 100uf @ 450v
1 x 4700uf @ 35v
1 x 100uf @ 100v (32v specified)

all have been used at some time .

PM me your address and I'll post them for you.

[shane]

Ok, two more questions for today, then I'll leave everyone in peace.

1) As Maplins no longer seem to do inductors, would the 10h device from WAD PSU2 work? (Ducks behind sofa to avoid Nick repeating warnings about changing working designs....)

2) Nick, since you rejected the original tx due to hum, does that mean you were building it into the same case as the Phono2? I'd assumed that I would need to build the supply as a remote entity with an umbilical, but it would be nice if I didn't have to.

[Nick]

Yes, the original inductor should be fine.

I was building it all into the one box, if you are building with two boxes then it may well be much better and just use what you have. Just be aware of the extra dissipation requirements you may have.

Its just me getting grumpy(er)in my old age, of course you can do as you will, bit it gets a tad irritating if you

1. have a "it works" design
2. Someone build it, but does something different
3. Someone then needs help doing the something different
4. based on the someone doing something different and not liking the result, declares that the original design was crap.

[shane]

No danger of that, Nick. If it's crap, it's my fault, if it's brilliant it's yours.

PM Sent, Phil.

[Nick]

Yep, I wasn’t pointing at anyone in particular, but just having a grump. Must be still hung over from the weekend.

[pre65]

Yep, I wasn’t pointing at anyone in particular.

I apologise for trying your patience at times,or is it all the time.

[Mike H]

Not the same thing at all and yet in a similar vein, at the mo I seem to have got lumbered with helping someone on a Moto Guzzi forum to test whether he's got oil pressure or not (dodgy oil dash light, or is it?).

It's like trying to pull teeth.

All he's got to do is loosen something, turn the motor on the starter only (don't actually start it) and see if oil comes out. Yet he manages to make this relatively simple test incredibly complicated and I don't think he's done it yet.

[cressy]

tell him to loosen the sump plug

[Mike H]

We have asked "has it actually got oil in it" he says yes, but now I'm wondering.....

[IslandPink]

Moved on a bit since I last visited...
Good that the circuit's all there from Nick, see I was right about OA2 & OB2 Now, what's that NiCad doing in the cathode of the first stage though ? Good for sucking the life & colour out of the precious vinyl signal.