Hello Patrick,
Received the boards today. Thanks Mark, Patrick & Joachim.
Now I have some confusion regarding the BOM. This is the BOM I got from the thread.
4x 10R 0.5% SMD 0805 Digikey RR12Q10DCT-ND
2x 0R SMD 0603 Digikey P0.0GCT-ND
6x 100R 0.5% SMD 0603 Digikey RR08P100DCT-ND
2x 10k 0.5% SMD 0603 Digikey RR08P10.0KDCT-ND
2x 470R 0.5% SMD 0805 Digikey RR12P470DCT-ND
4x 220µF 25V Digikey P10271-ND
2x 150pF 16V PPS SMD 0603 Digikey PCF1461CT-ND
2x 18mH 5%, matched to 1% Mouser 434-02-183J
I understand that R2 and P1 from schematic are absent on the board. That leaves only R1, R3 and R4. R3 has been changed to 100R and also 2 additional gate stoppers of 100R have been added. I dont understand where 10R and 0R are used on the boards. I dont see them on schematic. Patrick, can you clarify?
Thanks
Received the boards today. Thanks Mark, Patrick & Joachim.
Now I have some confusion regarding the BOM. This is the BOM I got from the thread.
4x 10R 0.5% SMD 0805 Digikey RR12Q10DCT-ND
2x 0R SMD 0603 Digikey P0.0GCT-ND
6x 100R 0.5% SMD 0603 Digikey RR08P100DCT-ND
2x 10k 0.5% SMD 0603 Digikey RR08P10.0KDCT-ND
2x 470R 0.5% SMD 0805 Digikey RR12P470DCT-ND
4x 220µF 25V Digikey P10271-ND
2x 150pF 16V PPS SMD 0603 Digikey PCF1461CT-ND
2x 18mH 5%, matched to 1% Mouser 434-02-183J
I understand that R2 and P1 from schematic are absent on the board. That leaves only R1, R3 and R4. R3 has been changed to 100R and also 2 additional gate stoppers of 100R have been added. I dont understand where 10R and 0R are used on the boards. I dont see them on schematic. Patrick, can you clarify?
Thanks
Ignore my previous post, I got all the answers, I had missed the pdf Patrick had posted. Anyone building this and having the doubts I raised should look at Post #303 in this thread.
Thanks
Thanks
Hi to all member. I hope so to post it to the right place...
I have completed the board some time ago and the last days I have some measurements about this.
At first I am not familiar with this design and my theory electronic background isn't big.
I saw that this filter-buffer raise the upper acoustic frequencies from the 5KHz step by step with the almost 0.25dB at 24KHz and so up over the 50KHz.
Here is an ARTA capture with 96KHz sampling (it is from the headphone output of an EMU-0404 + buffer)
As I know, this filter designed from J.G for the 9022-9023 Sabre dac-chips. If I measured right by ARTA the output of 9023 (after the filter), the following capture demonstrate the comparison between the 9023 direct output via direct output + J.G filter/buffer (the black is from 9023 direct output). The AD captured done by analogue inputs of EMU-0404 (usb).
The upper raise of frequency response is clearly. I don't know if this is a choice by designer or not.
The same seems with the square wave of 20KHz.
Here, the output of Hameg generator was calibrated to 2Vrms (1KHz sinewave) and then a square wave achieved at the same level as before. The signal was driven to buffer input and the output of buffer was driven to oscilloscope for capturing through Pomona 50 Ohm resistor termination.
There is an overshooting, probably normal cause the upper lift of frequencies.
I observed that if the signal was closer to 2.87Vrms (with reference to 1KHz sinewave) the captured square was almost perfect.
Sorry for my english...I would like the opinion of more experienced members with this design.
I have completed the board some time ago and the last days I have some measurements about this.
At first I am not familiar with this design and my theory electronic background isn't big.
I saw that this filter-buffer raise the upper acoustic frequencies from the 5KHz step by step with the almost 0.25dB at 24KHz and so up over the 50KHz.
Here is an ARTA capture with 96KHz sampling (it is from the headphone output of an EMU-0404 + buffer)
As I know, this filter designed from J.G for the 9022-9023 Sabre dac-chips. If I measured right by ARTA the output of 9023 (after the filter), the following capture demonstrate the comparison between the 9023 direct output via direct output + J.G filter/buffer (the black is from 9023 direct output). The AD captured done by analogue inputs of EMU-0404 (usb).
The upper raise of frequency response is clearly. I don't know if this is a choice by designer or not.
The same seems with the square wave of 20KHz.
Here, the output of Hameg generator was calibrated to 2Vrms (1KHz sinewave) and then a square wave achieved at the same level as before. The signal was driven to buffer input and the output of buffer was driven to oscilloscope for capturing through Pomona 50 Ohm resistor termination.
There is an overshooting, probably normal cause the upper lift of frequencies.
I observed that if the signal was closer to 2.87Vrms (with reference to 1KHz sinewave) the captured square was almost perfect.
Sorry for my english...I would like the opinion of more experienced members with this design.
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Many thanks for the answer...and I am very sorry because I have upload my questions not to right place.
I continued my post here
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