Timeline for Converting Balanced Audio to Unbalanced Audio without Damaging Sink
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Mar 21, 2023 at 22:05 | comment | added | physiii | @glen_geek Good idea about using SpectrumLab. Can you checkout my modified circuit? I removed the regulator and added jfet's for attenuating when there isn't power. | |
| Mar 21, 2023 at 22:02 | history | edited | physiii | CC BY-SA 4.0 |
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| Mar 21, 2023 at 20:01 | comment | added | glen_geek | @physiii power supply rejection ratio of LM358 for -ve supply is poor @ 10kHz where 7660 oscillates. (-45dB). I still would suggest trying 7660 direct...as a precaution, I'd send audio to SpectrumLab to look for 7660 10kHz-20kHz injection. Personally, I'd not hear anything that high-frequency, but you might. As-is, I'd bet negative-going peaks are likely clipped. | |
| Mar 21, 2023 at 19:12 | comment | added | physiii | @glen_geek Thank you for the catch - since my output is less than 2 Vpp I was more concerned about reducing noise than coming too close to the negative rail. I noticed the 7660 has a built in regulator, do you think I can just remove the 7905 section? | |
| Mar 21, 2023 at 17:36 | comment | added | GodJihyo | Could you put the attenuation after the opamps? I'd think that would be better as far as noise is concerned, but then the opamp output has to swing the full input voltage, so that may be a problem. | |
| Mar 21, 2023 at 17:07 | comment | added | Finbarr | You could just use a couple of small audio transformers. I very much doubt you'd damage the mic inputs on your motherboard anyway. | |
| Mar 21, 2023 at 17:03 | comment | added | Andy aka | @glen_geek good spot. | |
| Mar 21, 2023 at 16:59 | comment | added | glen_geek | Am concerned with the -5V DC supply: doesn't that 7660 put out -5V on pin 5? The 7905 regulator that follows requires at least -7V on its input pin. Do you really have a regulated -5VDC at 7905 output pin? | |
| Mar 21, 2023 at 16:55 | comment | added | Simon Fitch | I vote for 2, for simplicity. | |
| Mar 21, 2023 at 16:49 | comment | added | Andy aka | I'd go for 2 because it's easier and is clearly going to work. Having only a -5 volt rail to turn off the JFETs may not work. | |
| Mar 21, 2023 at 16:44 | history | edited | winny | CC BY-SA 4.0 |
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| Mar 21, 2023 at 16:44 | history | edited | physiii | CC BY-SA 4.0 |
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| Mar 21, 2023 at 16:43 | comment | added | winny | I'd go for JFET. | |
| Mar 21, 2023 at 16:43 | history | edited | physiii | CC BY-SA 4.0 |
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| Mar 21, 2023 at 16:36 | history | asked | physiii | CC BY-SA 4.0 |