1Kohm cermet potentiometer
Hello, I finally implemented the 1K pot in my dac (AYA4), a linear cermet as sugested in one of the blog aricles. But the problem is too much gain altough I'm driving my power amp directly. I'm stuck with the imprecisions/channel mismatch at the beginning of the pot track.
For now I lowered the IV resistor to 1K instead of the 1K5 (luckily, I had those of the same quality), which improves the situation. I'm now at maybe 10° to 20° angle from start, still a bit low when listening silently late at night.
Was also thinking of increasing the output resistor of the AYA4 or add another resistor in series, but that seems less ideal to me... adding a series resistor is moving away from that optimal load for this dac, which was around 800Ohms if I remember well.)
I was wondering what the best way would be to loose some more gain in my dac and if the 1K IV is a good choice..
Thanks,
Berny
Mistake, I have the AYA II 2014
Hi Berny,
I see no problems using 1 kOhm with OPA861 I/V. I did not run the actual performance test while varying its "collector" load, but in TI papers you will find resistors like 50 Ohm normally used there. In fact, a lower resistor value, i.e. lower voltage might be somewhat advantageous at this point, taking into account relatively limited voltage compliance.
As for the series element in the shunt potentiometer, the rule is the lower the resistance, the better the sound – and it applies as long as the source can drive it, and as it fits comfortable listening levels. As I understand your situation, now you need maybe a decibel or two of attenuation more, so I guess something like 1.2 kOhm could work for you. And it is of course always better to increase the resistor value than to add another part to the path.
Regards
Hello Pedja, I made a mistake.... I used the 1K pot in the regelar way, not as a shunt. Should have read your two blog articles again before soldering everything (and opening a new topic here), it was too long ago 🙂 Sorry, all fine now! Thanks for the help.
For other people reading this, it all starts here: https://www.audialonline.com/blog/model-a-volume-control/