Hi,
Got this kit thru ebay (Hong Kong). It works ok per my preliminary tests. I wonder if mods can be tried to improve things. My thoughts
= change PGA2310 to PGA2320 - a bit tricky the soldering
= remove C7 and C8. Will this act as filters?
- replace unknown brands of electrolytic with branded ones.
Also, this comes with a rotary encoder + push button switch. Where can I get a replacement ?
I have attached the schematic.
Got this kit thru ebay (Hong Kong). It works ok per my preliminary tests. I wonder if mods can be tried to improve things. My thoughts
= change PGA2310 to PGA2320 - a bit tricky the soldering
= remove C7 and C8. Will this act as filters?
- replace unknown brands of electrolytic with branded ones.
Also, this comes with a rotary encoder + push button switch. Where can I get a replacement ?
I have attached the schematic.
I would leave C7 and C8 in the circuit. If you remove them you may get EMC problems. If you drive the inputs from a low impedance source the low pass filter will be at more than 700kHz. No problem for audio, but good for attenuating RF.
Yes you are right. I remember a P-88 preamp based on 2134 I had built which was producing noise. Ultimately boiled down to the fact that source impedance was low.
In this case a low source impedance is not a problem in itself. The lower the impedance, the higher the low pass cut off frequency will be.
If the source impedance becomes very high the low pass cut off frequency will get lower though, but in normal cases that will not be a problem.
If the source impedance becomes very high the low pass cut off frequency will get lower though, but in normal cases that will not be a problem.
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