Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

low noise Pre-Amp / DAC power supply MJE15034 TL072 Regulator based on STUDER 900
low noise Pre-Amp / DAC power supply MJE15034 TL072 Regulator based on STUDER 900
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th June 2019, 06:14 PM   #141
Tix88 is offline Tix88  Italy
diyAudio Member
 
Join Date: Jan 2015
Hi everyone, I wanted to ask you, but is it possible to change the circuit to have a negative voltage? or do you have to create a virtual V- with an opamp ??
  Reply With Quote
Old 20th August 2019, 04:00 PM   #142
santodx5 is offline santodx5
diyAudio Member
 
Join Date: Jun 2014
Hi All,


I just found out bout this LPS today. I want to buy one and ask my friend to make it.


It will power my hard drive enclosure, It needs 12V/2.5A.


What transformer should I get? Any other changes in resistor than the default one?


Thanks
  Reply With Quote
Old 20th August 2019, 07:42 PM   #143
jonners is offline jonners  United Kingdom
diyAudio Member
 
jonners's Avatar
 
Join Date: Jan 2007
Location: Gloucestershire
Quote:
Originally Posted by santodx5 View Post
Hi All,


I just found out bout this LPS today. I want to buy one and ask my friend to make it.


It will power my hard drive enclosure, It needs 12V/2.5A.


What transformer should I get? Any other changes in resistor than the default one?


Thanks
I think 2.5A at 12V is probably asking a bit too much of this reg. However there are others who have posted here who may be able to give you a more technically accurate answer, if they are around.
  Reply With Quote
Old 20th August 2019, 10:41 PM   #144
j45yip is offline j45yip  Singapore
diyAudio Member
 
Join Date: Sep 2004
Location: Singapore
Quote:
Originally Posted by santodx5 View Post
Hi All,


I just found out bout this LPS today. I want to buy one and ask my friend to make it.


It will power my hard drive enclosure, It needs 12V/2.5A.


What transformer should I get? Any other changes in resistor than the default one?


Thanks
The L-Adapter by Salas suits your need better.
  Reply With Quote
Old 21st August 2019, 05:07 AM   #145
santodx5 is offline santodx5
diyAudio Member
 
Join Date: Jun 2014
Quote:
Originally Posted by j45yip View Post
The L-Adapter by Salas suits your need better.

What is the difference with Studer? Which one is better? I'm planning to add HPULN LT3045 to the power supply. I heard this is is a very best combo.



Actualy I will need 12V @ 2A, so studer will work.


Thanks
  Reply With Quote
Old 21st August 2019, 03:12 PM   #146
santodx5 is offline santodx5
diyAudio Member
 
Join Date: Jun 2014
I just check L adapter, it wont available until end of the year. I cant wait that long..


So far best option is Studer 900, can someone recommend other?
  Reply With Quote
Old 21st August 2019, 03:27 PM   #147
santodx5 is offline santodx5
diyAudio Member
 
Join Date: Jun 2014
Based on some seller on alienexpress says "The maximum current of the circuit is 1.5A. can't with 3-4A. Please pay attention to the use occasion, but the general preamp and decoding will not exceed 1A."




Lusya 5 24V STUDER900 Regulator Power supply board super LM317 LT1083 LT1085 DIY kit/finished board-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group


can someone confirm this? if it is true i wont be able to use it.


Thanks
  Reply With Quote
Old 23rd August 2019, 08:49 PM   #148
dtossan is offline dtossan  Canada
diyAudio Member
 
Join Date: Dec 2010
Location: Toronto
Quote:
Originally Posted by santodx5 View Post
Based on some seller on alienexpress says "The maximum current of the circuit is 1.5A..."
[COLOR=#ff0000]

can someone confirm this? if it is true i wont be able to use it.
If you are handy, you can increase the max current.

e.g. to get 2A output, remove D102 and D103. And change R107 to 0.33 ohms. Also check that the heatsink is capable for the power dissipation from your load (caused by the voltage difference between your transformer voltage and DC out voltage and the current draw of your load.)

See posts #73 to #93.
  Reply With Quote
Old 24th August 2019, 08:08 PM   #149
santodx5 is offline santodx5
diyAudio Member
 
Join Date: Jun 2014
Thanks.


Now I am thinking about the alternatives Sigma 11 PSU.


The σ11 regulated power supply


Does anyone know which one is better?
  Reply With Quote
Old 26th August 2019, 08:26 PM   #150
gizmo3 is offline gizmo3  Netherlands
diyAudio Member
 
Join Date: Jan 2018
Location: doetinchem
Quote:
Originally Posted by bButcher View Post
Received my board for about 10 days, use it to drive rbp 3b+ running moode connecting to an usb dac, the result is outstanding. So I spent some time study the circuit, run some simulation and do some mods on the board, here is some experience I would like to share:


(1) I modified the original circuit diagram to reflect where the clone board is different from the original one. Also each functional block is outlined with different colors.

Click the image to open in full size.


*I forgot to change C105 to 47u for the clone board.

(2) Minimum 9V AC is required to properly power the board, since TL072 need at least 10V for Vcc+ - Vcc-.


(3) To configure the output voltage, use the following formula.


[Vout - Vin+] = Vref * (R127 + R126 + R125)/(R127 + R126min~max) = Vout * R115/(R115 + R119 + Rrange)


--- Rrange is the combined value of R122, R123, R301
--- Vref is voltage across reference red led DL301


with real values substituted,


[Vout - Vin+] = 1.938V ~ 2.193V ~ 2.525V, @Vref = 1.8V (usual forward voltage for red led)

and


Vout = Vref * (46.3k)(5.5k + Rrange)/(33k ~ 43k)(3.3k)


or tabularize the different combinations of Rrange:


Range__H___M____L____Vout (V), @Vref = 1.8V

2.5k____x____x____x_____4.70 ~ 6.12
2.7k_________x____x_____4.82 ~ 6.27
2.98k___x_________x_____4.98 ~ 6.49
3.3k______________x_____5.17 ~ 6.73
10.3k___x____x__________9.28 ~ 12.09
15k_________.x_________12.04 ~ 15.68
33k____.x______________22.61 ~ 29.46



Note: this is based on Vref = 1.8V, on my board the measured value is around 1.875, with L point soldered, the lowest reached voltage is 5.17*1.875/1.8 = 5.39, too high for 5V supply, I also have to solder M point to bring the output to 5V.


From the table, one can see it doesn't cover the full range, e.g. there is no way to adjust to 18V. In this case, you better install your own resistor use the following formula:


Rrange = {Vout/Vref) * (3.3k)(33k ~43k)}/(46.3k) - 5.5k


To generate 18V, Rrange = (18/1.8)*3.3*38/46.3 - 5.5 = 21.6k (use 21.5k standard 1% value). You can replace any of H, M, L resistors and with the corresponding point soldered on.


(4) About the maximal current it can supply, with some simulation (thanks to fabio1068 for the tina model)


Click the image to open in full size.



From the simulation, the circuit start to fail between 1.67A to 1.83A. I'll suggest use it to drive at most 1.5A "peak" load.


(5) The noise figure: Since I only have a basic fluke multimeter and its minimal voltage resolution is 0.1mV, so this result is a rough estimation. After some modifications with the board, the following figures are measured.


rbp 3b+ + usb dac, music not playing, 0mV @terminal, 0mV @rbp 3b+ (< 50uV ?)


rbp 3b+ + usb dac + usb hard drive (use external usb hub swithing power), music not playing, 0.1mV@terminal, 0.1~0.2mV @rbp 3b+


rbp 3b+ + usb dac + usb hard drive (use external usb hub swithing power), music playing, 0.1~0.2mV@terminal, 0.2~0.5mV @rbp 3b+


*total current is about 0.5A


(6) The modifications I made on the board:


(A) The layout of the board is pretty bad, the measured resistance between input (right after rectifier diode) and output terminal (Vout) is around 14 mOhm, so I strengthen both power lines (yellow marked lines in the circuit diagram) with solid wires.


(B) Add 0.47u caps across the 4 input rectifier diodes.


(C) Earth the input ground (p1/8,9 in the circuit diagram) with a 0.01u cap.

(D) Use a line filter before the transformer.


(E) Change R102 from 10k to 5k. This is not about reducing noise, more about put 5.1V zener at proper operating point (~1.5mA), especially when drive the board with 9V AC.


The above is what I have done so far, hope my experience can help others.
Thanks for the measurements and especially the 5 volts I got this also basically at 5.41 volts and not lower but after soldering L and M now exactly at 5.02 volts.

thanks again.

Last edited by gizmo3; 26th August 2019 at 08:31 PM.
  Reply With Quote

Reply


low noise Pre-Amp / DAC power supply MJE15034 TL072 Regulator based on STUDER 900Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Gerbers - Low noise Power Supply for pre-amp type circuits mlee Power Supplies 0 9th July 2014 08:38 PM
TL072 based Electret mic pre-amp not working correctly... Tinny and quiet. fraseyboy Chip Amps 29 12th May 2014 04:31 AM
Low Noise Linear regulator power supply leonm12 Power Supplies 13 13th June 2011 03:50 PM
preamp supply LOW power LOW noise LOW cost drdagor Power Supplies 1 13th September 2010 11:39 PM
Simple and Low noise Pre-regulators for DAC machinow Digital Source 2 10th September 2004 01:04 PM


New To Site? Need Help?

All times are GMT. The time now is 12:01 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki