Is regulated PSU for phono preamp a MUST?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
analog_sa said:


To power what exactly?


Solid state phono preamp using OP637 Left channel input from turn table left output then the OPA637 phono preamp output into left input Solid state line stage pre-amp the output to active crossover the output to power amps.

Another OPA637 will do the same but for the right channel this time.

Thanks in advance,
The Butcher:D
 
This vague description probably means you won't be dealing with low output moving coil carts. In this case regulation is not really a must as far as noise from the PS is concerned. The sound will, of course, be different depending on the PS arrangement. IME a good regulator (not a 78**/317) brings nice improvements in many areas.
 
Ah, is the pick up you were questioning..

To keep the cost down I will stay with moving magnets cartridges. The only regulated PSU that I am capable of making would be the 7812/7815 or LM338K ones, any other ones I have no clue. But CLC I am very confident with and I like CLC because they are easy to make and runs cool no heat sink worries.

When people use lead batteries for the phono preamp PSU do they regulate it too?

Regards,
The Butcher:D
 
Really a "wall mart wall wart" (lol) is not going to do it ! it came from wall mart so the components inside are probably fakes and it will catch fire and burn your house down.

after that happens none of the othere reasons not to use a wall mart wall wart even matter </joking>

seriously though, most crappy DC wall warts are half wave rectified with minimal capacitor, and assume the device being powered has a regulator. (and they do not often come bipolar.

AC wall wart on the other hand is just a transformer and you do the rectifier/smoothing/regulation your self. it might be nice if you want to make a really tiny project.


look at this
http://sound.westhost.com/project05.htm it might be a better way to go.
 
http://www.alw.audio.dsl.pipex.com/jung_schematic.htm

http://www.aoselectronics.com/jungsrpcb.html

http://home.comcast.net/~walt-jung/wsb/PDFs/Improved_PN_Regs.pdf

will transform op amp based circuits. The AOS boards are a bargain! As ALW has eluded to, the Jung Super Regulator is a clear step superior to the Sulzer type circuit.

IMO, these are the steps

Passive, no reg
Zener based
Capacitance multiplier
78XX, 79XX
317/337
LT108X
Sulzer
Jung Super Regulators.

Take your pick, each progression wil have greater transparency, depth and micro dynamics.

Take A pair of super regulators from AOS
Combine with
http://www.sound.westhost.com/project06.htm
and you have a ready to go project that should sound very good with the OPA637 you've chosen.
 
So Super Regulator is going to be then

I am going to use this thread to record my Phono Preamp Project. After reading this forum I have picked this preamp as my project. I am building from this schematic by refer to the thread http://www.diyaudio.com/forums/showthread.php?postid=300426#post300426

For those of you who know the Butcher style should aware of the fact that appearance of electronics have no bearing here. I just want every penny that I spent on my projects get its return on the audio performance as my preference rather than the look of it. When it works then I will think of a slightly better case for them.

I already have all the parts on hand for the phono preamp as posted in the schematic from fastcat95. Now with Mikett's suggestion I am going to get some AOS boards. My next task is to compile a BOM for the power supply. I am thinking to do a mono block phone preamp so I am going to have 2 power transformers one for each channel. Each channel will have to use 2 super regulator PCB, one for positive and one for negative so I need to order 4 PCB boards. From their site I can compile a list of parts base on the negative and positive schematics.

The BOM for the PSU will get updated as the project progresses:
2 @ power transfomers 12-0-12 VCT 1A
4 @ Super Regulator pcb
2 @ panel mount power recepticles
2 @ power cords
2 @ panel mount power switches
2 @ inline fuse holders
2 @ slow blow fuses rate a 500ma

The Butcher:D
 
Forgot to mention the pre-pre-pre amprefier

I was given a old MM cartridge (used for 1 month and is free). The phono preamp will be built base on this loading:-

PEARL
Moving Magnet
Stylus Type: 0.2 x 0.8 mil. Elliptical Configuration.
Frequency Response: 12 Hz. - 30 kHz.
Output Voltage: 5.0 mV per channel at 1 kHz.; 5 cm./sec. peak recorded velocity. Output from each channel within 2 dB.
Channel Separation: Minimum 30 dB at 1 kHz.
Channel Balance: Within 0.5 dB.
Compliance: 15 x 10-6 cm/dyne.
Optimum Load: 47, 000 ohms resistance in parallel with 250 to picofarads total capacitance.
Tracking Force Range: 1.5 to 2.0 grams.
Recommended Tracking Force: 2.0 grams.
Net Weight: 6.0 grams.
Mounting: Standard 1/2" (12.7mm) Mounting Centers.
User Replaceable Stylus RS-PEA
"Moving magnet phono cartridge with alloy cantilever, bonded elliptical stylus and 4.0mV output


The Butcher :D
 
Regulation is cheap'n'easy, relatively, but...

Jcarr's comments about L input are correct- it's a great way to have low noise and good regulation but stay passive. I wonder, though, since this is more-or-less a constant current load (i.e., it's not an AB power amp) how important regulation really is. And given that the PSRR is better than 60dB at all audio frequencies, I really, really wonder how low noise it really has to be. As a frugal butcher, you might find that a simple CRC filter is all you need.
 
Hi Chris,
the proposed input capacitance seems a bit high @ 250pF.
Try making it adjustable unless you know that this cartridge needs a very high value.
Remember that the arm and interconnect cables also have capacitance that adds to the input value.
I would try switched steps of 0pF, 50pf and 100pF to start giving 4 choices until you hear what it sounds like.
 
Yes Andrew,

I have actually think of making the R1 and C1 (the input loading) parts of the phono preamp with female pins on the board or even outside the box so that I can just push different cap values in. You are quite right that the cartridge will be changed quite often and I want to able to swap out C1 on the fly without soldering. Thanks for the suggested cap values, I will try and keep these values in my supply box from now on.

The Butcher:D
 
Mikett said:
http://www.alw.audio.dsl.pipex.com/jung_schematic.htm

http://www.aoselectronics.com/jungsrpcb.html

http://home.comcast.net/~walt-jung/wsb/PDFs/Improved_PN_Regs.pdf

will transform op amp based circuits. The AOS boards are a bargain! As ALW has eluded to, the Jung Super Regulator is a clear step superior to the Sulzer type circuit.

IMO, these are the steps

Passive, no reg
Zener based
Capacitance multiplier
78XX, 79XX
317/337
LT108X
Sulzer
Jung Super Regulators.

Take your pick, each progression wil have greater transparency, depth and micro dynamics.

Take A pair of super regulators from AOS
Combine with
http://www.sound.westhost.com/project06.htm
and you have a ready to go project that should sound very good with the OPA637 you've chosen.


Wow it is getting expensive with the AOS boards, they are not bargain with my income standard. For this project I need 4 boards for mono blocks, just the unstuff board alone will cost around $70US and may be custom charges yet unknown..
:eek:
 
I believe AOS is in Canada so there are no custom charges and shipping is minimal
In my opinion it's better to have a better regulator running two channels than multiple inferior ones in monoblock fashion. The sound of the power supply is significant on op amps as many chip amp zealots have discovered.
You can always etch and drill but a "proven" layout is important in this supply stability. Proven layouts can be found in the Audio Amateur/AudioXpress which are kept in the Toronto Public Library Science reference section. Xerox copiers are available.
You can always try to get a price break on multiple boards, just ask and see if it happens.
 
When ordering from the USA to arrive in Canada, be aware that if the item costs less than $10US. There are no applicable GST and PST and handling charges. If it is over $10, GST,PST will apply as well as a $5 handling charge by Canada Post.
Request that the suppier ship via USPS NOT UPS or FEDEX or you'll end up paying a small fortune for their handling and brokerage charge.

So choose USPS and pay more for HANDLING and LESS for the product cost from the supplier. "Wink Wink".
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.