Jjazz,
You may want to use a 25V + 25V transformer instead to give the LM317 a bit more headroom and increase the values of C3 C4 R4 R5 to provide better filtering. eg: 1000uF / 7R.
Cheers
Hi Ryan!
You're right Ryan, it's very expensive, and I'm still not sure if the end result of the dac is good for me and spending less money is a good idea.
I will use the standard power supplies that I have and I will try to make this power supply. I have no knowledge of electronics, I am a component assembler, but I think that diagram is easy to understand and do with the help of a friend with that knowledge.
Thank you very much for your help, I am very grateful.
You're right Ryan, it's very expensive, and I'm still not sure if the end result of the dac is good for me and spending less money is a good idea.
I will use the standard power supplies that I have and I will try to make this power supply. I have no knowledge of electronics, I am a component assembler, but I think that diagram is easy to understand and do with the help of a friend with that knowledge.
Thank you very much for your help, I am very grateful.
Hi Ryan!
I retake the project in its final phase (many pieces and lots of money). I'm going to order the pieces and I have two doubts.
The first if the secondary transformer for this scheme should be + 25.0.-25?
And the other is if the resistance of 7ohm can be 2w instead of 1w and tolerance of 5%. This is ok?
Best regards
Hi Jjazz,
Yes you could use 2W at 5%, no problem.
For the transformer, yes you could use a 50V CT (25-0-25), or you could use one with two separate 25V windings.
Ryan
PSU
Hi guys,
I might give this set up a go. Ill try it without the zener reg also.
The darlingtons could be BD679 and BD680. The npn bjt could be MJE243G.
I've not tried this so just remember that if you build this.
The output has 1uV per division. The ripple before the cap multi is about 560mV peak to peak.
The transformer I modeled was a 24V+24V.
If I try this and it works well I might make a PCB.
Hi guys,
I might give this set up a go. Ill try it without the zener reg also.
The darlingtons could be BD679 and BD680. The npn bjt could be MJE243G.
I've not tried this so just remember that if you build this.
The output has 1uV per division. The ripple before the cap multi is about 560mV peak to peak.
The transformer I modeled was a 24V+24V.
If I try this and it works well I might make a PCB.
Attachments
8V and 26V PSU
If I just use LM317 based PSU; shouldn't it be fine for 8V and 26V? The board already has upstream local regulators to supply +-5V and -15V. LM317 is old and has just average performance. Or should we use state of the art super regulator PSU?
I am trying to get a sense of importance of 8V and 26V for this board.
If I just use LM317 based PSU; shouldn't it be fine for 8V and 26V? The board already has upstream local regulators to supply +-5V and -15V. LM317 is old and has just average performance. Or should we use state of the art super regulator PSU?
I am trying to get a sense of importance of 8V and 26V for this board.
Using a 317 may be a good starting point, but i would suggest to have a play around with different circuits using different filtering techniques and have a listen to see if you like the sound or not. Having a regulator before the onboard regulator is not necessary, you could just use a basic rectifier with CRC/CLC or whatever tickles your fancy.
Hi Ryan!
I hope the holidays are going well.
I'm taking advantage of the holiday to mount the DAC.
I have a problem with the 26v power supply. I followed your design and the output voltage is DC 25.2 V , not the expected 26v. The input AC voltage oscillates between 25.2 and 25.5 V (I don't have good electrical power at home).
There is something I can do to get the 26v, maybe some check to see that everything is fine (I think it is or would not give those 25.2v)
Thank You very munch.
Best regards
Hi Jjazz,
Check the voltage going into the LM317, it needs at least 2V across it. If that is the case then use lower value resistors in the CRC. You may be getting lower voltage due to a low mains voltage.
The labels on the -5V are the wrong way around. So your measured voltage is correct. I hope you have dummy loads or a chip in the slot while measuring the voltage, otherwise the pass PNPs will get HOT.
Yes you need the 8V supply, this is for the attenuators. Using the SSLV1.1 BiB may be ok as long as the outputs are kept floating, but using a shunt reg to feed another shunt reg is not necessary.
My plan for my 26V supply:
Rectifier->2200uF cap -> capacitance multiplier in positive and negative line -> common mode choke -> 1000uF and 1uF-> 26V input.
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