nysulli
500+ Head-Fier
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Quote:
i realize that without those caps you have a variable resistance on one side of the opamp, and thus its pretty difficult to balance the input and output sides of the opamp, but even so, i would think one could do much better balancing the load on either side to not have dc offset vary from 1mv to 20mv, even being a noob builder when i made my minified pint, i was able to sort out my configuration such that my offset varies from .5mv to at most 1mv at full volume, doubling of the offset i can see, but varying 2000% over the full swing of the volume pot just doesn't sound right, if it was 10mv to 20mv, i wouldn't think that much of it, its just the order of magnitude change that makes me wonder
Originally Posted by Pars Actually, with a mini3-fied PINT, because of the lack of input caps and the bipolar opamp(s), the amp will see a variable resistance from the pot on its input. The offset will therefore climb as the volume is increased (because the input bias currents change with pot level). <20mV at full volume isn't too bad. |
i realize that without those caps you have a variable resistance on one side of the opamp, and thus its pretty difficult to balance the input and output sides of the opamp, but even so, i would think one could do much better balancing the load on either side to not have dc offset vary from 1mv to 20mv, even being a noob builder when i made my minified pint, i was able to sort out my configuration such that my offset varies from .5mv to at most 1mv at full volume, doubling of the offset i can see, but varying 2000% over the full swing of the volume pot just doesn't sound right, if it was 10mv to 20mv, i wouldn't think that much of it, its just the order of magnitude change that makes me wonder