So in anticipation of a record player arriving at my door, I have decided to kind of make my own RIAA step. I picked up the phono board from an older Yamaha CX-830 preamp, and I figured I could try to make a power supply for it and see if I could at least make it work, or maybe I could even make it sound good.
What I need is a +18 0 -18 supply and I'm guessing it doesn't need to be very powerful, but from what I've read it needs to be quiet. Are there any good DIY designs out there, either here or other places. I'm considering one of Rod Elliott's designs. Does anyone here have experiences with those?
Thanks
What I need is a +18 0 -18 supply and I'm guessing it doesn't need to be very powerful, but from what I've read it needs to be quiet. Are there any good DIY designs out there, either here or other places. I'm considering one of Rod Elliott's designs. Does anyone here have experiences with those?
Thanks
If you want +/- 18v, why not use 2x9v transistor batteries for '+' and 2 for '-'? If this works, you can then make a better-sounding battery power supply by using 3x6v SLAs for '+' and 3 for '-'. That'll be "beefy" enough to last quite a long time, I would think.
Regards,
Andy
IMHO you should just make yourself a +/- 18VDC power supply using LM7818 and LM7918 fixed regulators. You will find many threads here knocking fixed regulators like those as inferior to discrete or adjustable versions, but since you are implementing a consumer grade preamp board, you are unlikely to hear a difference.
Yeah, my first option was to do that using Rod Elliott's design. Just wanted to see if there were any other designs out there that would be easier and/or better. Not that his design is very complicated at all, but it's always good with a second opinion.
I would advise against going the 7xxx regulator route (or the lm317). In my brief experience, these regulators completely wreck the sound. Simply awful sound.
I built the Le Pacific RIAA which has a very low parts count and is more sensitive to the PS than perhaps other designs.
Get a simple CRC supply, or one of the cap multipliers on Rod Elliot's pages. If you want to go one better, build a shunt reg.
There is a group buy for DCB1 boards (check in the group buy section), many people are using those as a shunt reg. It is ideal for your application and will be very hard to beat in terms of sound.
I built the Le Pacific RIAA which has a very low parts count and is more sensitive to the PS than perhaps other designs.
Get a simple CRC supply, or one of the cap multipliers on Rod Elliot's pages. If you want to go one better, build a shunt reg.
There is a group buy for DCB1 boards (check in the group buy section), many people are using those as a shunt reg. It is ideal for your application and will be very hard to beat in terms of sound.
It took me a good few months to get the hang of it.
Basically, it is a constant current source feeding a mosfet which shunts a large portion of current to ground, and the load sees only a small portion of it, thus achieving good regulation.
The group buy is for PCBs for a direct coupled B1 buffer, which is a unity gain active buffer/volume control, designed by Nelson Pass. You can find the original article on passdiy.com
Salas, another member here, added direct coupling and a shunt reg to the original B1 buffer. The shunt reg part of the PCB can be easily adopted as a PS in other designs.
If you don't want to get this deep so soon, just build a CRC supply. Again look at firstwatt amplifier power supplies, found at firstwatt.com
Hey, thanks for the info. But when you say that the shunt reg part of the PCB can be adopted to be used as a power supply, it's already too complicated for me.
Checked out the firstwatt site and couldn't immediately locate any pages just for power supplies there. I'll look around a bit more and see what I can figure out.
Checked out the firstwatt site and couldn't immediately locate any pages just for power supplies there. I'll look around a bit more and see what I can figure out.
The CRC supply is simple. Take a look at this:
My First Tube Power Supply
Now check this:
http://www.firstwatt.com/downloads/f1_srv_man.pdf
Go to the power supply, that is what you want. You can do with smaller caps, maybe 1000-4700 uF. The CRC sections act like a filter for the ripple.
There is group for a pcb version of the same supply as the one above. Go here:
http://www.diyaudio.com/forums/group-buys/134554-gb-f5-pcb-102.html#post2002192
Hope this helps!
My First Tube Power Supply
Now check this:
http://www.firstwatt.com/downloads/f1_srv_man.pdf
Go to the power supply, that is what you want. You can do with smaller caps, maybe 1000-4700 uF. The CRC sections act like a filter for the ripple.
There is group for a pcb version of the same supply as the one above. Go here:
http://www.diyaudio.com/forums/group-buys/134554-gb-f5-pcb-102.html#post2002192
Hope this helps!
Walt Jung has some info on regulators...
Services
A bunch of power supply links:
Power Supplies and Regulators for Hi-Fi Audio
I suspect a '317/'337 or the LT upgrades would be good enough. Somewhere I've got a layout that works with just about any positive/negative pair of 3-terminal regulators, whether 78/79, 317/337, in just about any package other than surface mount or TO3. It's got locations for input and output caps and protection diodes, and was based on a schematic from Audio Amateur (maybe by Walt Jung).
Services
A bunch of power supply links:
Power Supplies and Regulators for Hi-Fi Audio
I suspect a '317/'337 or the LT upgrades would be good enough. Somewhere I've got a layout that works with just about any positive/negative pair of 3-terminal regulators, whether 78/79, 317/337, in just about any package other than surface mount or TO3. It's got locations for input and output caps and protection diodes, and was based on a schematic from Audio Amateur (maybe by Walt Jung).
I agree with you wholeheartedly. I heard this idea about 10 years ago ... so I built up a cathodefollower-based PS designed by an amplifier-designer mate of mine, to replace the LM317-based PS in my Oz designed, retail phono stage.
Not surprisingly, I thought it did sound better ... and when I took the modded phono stage over to the house of the guy who built them, and we compared mine against his stock unit, even he had to agree (and he was biased!
)So I no longer use LM317s and their ilk.
Regards,
Andy
Can you guys get a dose of common sense and not confuse the newbie? You want him to implement a rip-out preamp with a discrete regulator? Yeah, it really makes sense to put all that time and effort on something which probably is stuffed with +80/-20% ceramic caps! Of course he'll hear a difference 
Honestly, is there no more reason here?
Honestly, is there no more reason here?Can you guys get a dose of common sense and not confuse the newbie? You want him to implement a rip-out preamp with a discrete regulator? Yeah, it really makes sense to put all that time and effort on something which probably is stuffed with +80/-20% ceramic caps! Of course he'll hear a difference
In my case I will at least start with something that I can understand from the instructions and schematics given. My knowledge level is not high enough yet that I can take something and just "apply it to work" for my purpose. In any case, I appreciate the information I have gotten in this thread.
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