Bugle PS

[mantisory]

Hi all...
I have a bugle phono pre, currently using rechargeable 9V batteries, that'd i'd like to place inside an integrated amp i am building. I also have a dual 12V 2A transformer to use, and am wondering...should I use the transformer with a bridge rectifier (4 1N4007's or something), unregulated with smoothing Caps, or should i use the LM317/337 pair that I have to regulate it? I need +/- 15V to power the bugle (www.hagtech.com/bugle)
Thansk for your help
Mantisory

[dhaen]

I don't understand why you don't just build (or buy) the PSU they recommend:
psu . It's very simple.

Some designs that were originally meant for battery power may have particular psu requirements WRT ripple and noise.

[mantisory]

yeah, i suppose i could...
i thought perhaps i could use the parts i have on hand, which don't really match up to what his PS requires, that's all...
Mantisory

[dhaen]

Ah, I didn't appreciate that you needed to use "in stock" parts

What sticks out about their psu is the use of Schottky diodes as a bridge rect. That'll be much quieter than the 1N400X diodes, so is a must.
R2 and R12 form noise filtering too and should be incorporated.
As for regulator types, I don't think theirs are that special.
The other Schottky's are just "fussing" IMO.

[mantisory]

thanks!
So i guess I could just replicate the circuit with my own parts, and set R6 and R9 to give me the voltage i need...is this correct?
Mantisory

[dhaen]

Presumably you know that the 317/337 are variable regulators and need voltage setting resistors. You can find the calculations here on the data sheet: NS

[jleaman]

Originally posted by dhaen
I don't understand why you don't just build (or buy) the PSU they recommend:
psu . It's very simple.

Some designs that were originally meant for battery power may have particular psu requirements WRT ripple and noise.

Thanks for the schematic. I'm going to build one..

[mantisory]

Presumably you know that the 317/337 are variable regulators and need voltage setting resistors

Yes, thanks!
Mantisory.

[amplifierguru]

Hi Mantisory,

You would do well to use the 317/337 set to 15V and 1N4002's up. The adjustable regs have much better performance than the fixed ones recommended so better to use what you have.

The OPA2130 (ugh) has very poor HF PSRR so it should benefit considerably. A discrete regulator using a pass transistor, current source and TL431, or LT 317/337 would be better. You can increase R2, R12 and increase R6,R9 to lighten loading.

Then save up for some better chips, those 2130's are noisy, low bW/SR. Try an shoehorn some OPA637 singles in and sit back and enjoy the relative silence and cleanness.

[dsavitsk]

Originally posted by amplifierguru
Try an shoehorn some OPA637 singles in and sit back and enjoy the relative silence and cleanness.

Yes, that sounds like a great idea. Add $110 worth of opamps to your $50 phono stage.

If you are going to spend that kind of money, you might as well get a better phono stage. Short of a different circuit, there are plenty of other good opamps you can try that are much cheaper than the opa637.

-d