i2s, yes - oops.
It might be oscillation? I'll try the resistor - is small 1R, 10R, 100R? Or 1K?
Have to think about how to use regulators. The system power is 24V so I used dual-output Traco modules for 5+/- and 12+/-, being spot-on there's no room for the voltage drop of an LM317/337, eh?
How about a Zener?
It might be oscillation? I'll try the resistor - is small 1R, 10R, 100R? Or 1K?
Have to think about how to use regulators. The system power is 24V so I used dual-output Traco modules for 5+/- and 12+/-, being spot-on there's no room for the voltage drop of an LM317/337, eh?
How about a Zener?
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It might be ... try 2R2. Look into datasheet for some specification about capacitors (capacitive load) and it can tell you more about that ... try to give only 100uF.
There is no room for LM317/337 (they also don't like output capacitors, only the minimum specified in datasheet)... zener based regulators are nice and simple. Problem is a voltage drop of a zener diode (depending on the temperature). Active regulators need only small output capacitors.
There is no room for LM317/337 (they also don't like output capacitors, only the minimum specified in datasheet)... zener based regulators are nice and simple. Problem is a voltage drop of a zener diode (depending on the temperature). Active regulators need only small output capacitors.
Thanks for the pointer, this is valuable learning for me.
The +/-12V converter has a max capacitive load of 520uF per output, +/-5V converter max 1470uF per output. If I understand the schematic, each 12V output sees 4 x (100uF + 100nF) capacitors and each 5V output sees 2 x (47uF + 100nF), plus whatever capacitance exists in the other components. So 5V is definitely not a problem but guess it's getting close on the 12V side?
If I'm truly off the path let me know and I'll go study.
The +/-12V converter has a max capacitive load of 520uF per output, +/-5V converter max 1470uF per output. If I understand the schematic, each 12V output sees 4 x (100uF + 100nF) capacitors and each 5V output sees 2 x (47uF + 100nF), plus whatever capacitance exists in the other components. So 5V is definitely not a problem but guess it's getting close on the 12V side?
If I'm truly off the path let me know and I'll go study.
Hi Paddy,
I attached the schematic of the hybrid linear/DCDC converter PSU I had made up for DAC projects. It uses a linear regulator to feed the Murata converters a steady 12vdc input. The +/-15v converter feeds a parallel TPS7A3901 regulator set for the +/-12vdc Miro's dac board requires. The +/-5vdc converter does not have the additional regulator.
I attached the schematic of the hybrid linear/DCDC converter PSU I had made up for DAC projects. It uses a linear regulator to feed the Murata converters a steady 12vdc input. The +/-15v converter feeds a parallel TPS7A3901 regulator set for the +/-12vdc Miro's dac board requires. The +/-5vdc converter does not have the additional regulator.
I am not an expert in switching power supplies, it's quite complicated for audio.
Install smaller capacitors for 12V outputs, or give separate controllers for each channel ... or install 2R2 resistor instead of jumpers.
Adding analog regulators would be best. DC-DC for +-15V. From that +-12V analog regulators with +-3V room could be enough (use a low input and output capacity).
Vunce helped best
Install smaller capacitors for 12V outputs, or give separate controllers for each channel ... or install 2R2 resistor instead of jumpers.
Adding analog regulators would be best. DC-DC for +-15V. From that +-12V analog regulators with +-3V room could be enough (use a low input and output capacity).
Vunce helped best
I apologize Manniraj
I’ve used the V5 and V6 Classics, I preferred the V6 over LM6171, OPA1611 and NE5534 opamps. But, the OPA861 I/V boards (Aya II) I fabbed up sound really good also, that’s what I’ve been listening with most of the time.
Thanks Vunce, I will try with my V6 classic one piece and vivid another piece
I will take a look into your preferred option - OPA861 I/V boards (Aya II). Where did you procure this board? Any pointers.
Thanks again.
I’m thinking of ordering from Rochester Electronics (en-US)
: Part AD1862N.
The minimum quantity is 11 and the price before shipping is $254.65.
If there is interest, I will create a small GB.
The Oshpark PCB is $52.45 for 3 boards.
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Check out post#537
Hi,
I have to replicate this schematic for each channel? Compared to opa627 is it better?
Thanks
https://www.diyaudio.com/forums/att...input-nos-2r-vdac_buf-july-15-schematic-2-pdf
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Yes, one pcb per channel. The onboard regulator drops the +/-12vdc supplied from the opamp socket pins 4 and 7 to the required +/-5vdc.
Good question, I do have OPA627’s on the way.....
Hello,
There is no particular interrest to use an opa861 as a buffer. I will keep the opa861 for the I/V but will try something else as a buffer in your shoes... The C10 is not wanted as well. Which buffer ? the opa 1656 (double) used single channel makes sense with 1206 smd pads for close decoupling. Imho, YMMV
There is no particular interrest to use an opa861 as a buffer. I will keep the opa861 for the I/V but will try something else as a buffer in your shoes... The C10 is not wanted as well. Which buffer ? the opa 1656 (double) used single channel makes sense with 1206 smd pads for close decoupling. Imho, YMMV
Thanks, Vunce! After studying, I think that my power stuff looks a lot like yours, but with fewer discrete parts
Really by luck I selected Traco regulated DC-DC converters, so the outputs are actually already regulated.I checked the DAC output on the bench with an oscilloscope and can't find any sign of noise in the output, which makes me think the noise I hear is indeed ground-related, especially as I had a similar problem with a commercial DAC which was resolved with better grounding inside my DIY preamp.
Next up - try installing the caps and inductors recommended by Traco for EMI control to see if the weird intermod-like sounds heard in specific passages go away.