I recently built an IGC based on Peter's design and am very pleased with the results. The sound is really very good and it has a good amount of power. There was one problem I encountered that I was hoping others might be able to shed some light on.
My amp uses the recommended 4.7 uF bipolar input cap. I noticed that the overall performance was excellent including very acceptable bass response and very open and clear high frequencies. However, there was a "fuzziness" in a very narrow midrange band (affecting tenor voices and instruments in the same range). I tried shorting the input caps and that appeared to eliminate the problem. I was wondering what others have experienced with different values and types of the input cap. Also, what is the purpose of the input cap?
My amp uses the recommended 4.7 uF bipolar input cap. I noticed that the overall performance was excellent including very acceptable bass response and very open and clear high frequencies. However, there was a "fuzziness" in a very narrow midrange band (affecting tenor voices and instruments in the same range). I tried shorting the input caps and that appeared to eliminate the problem. I was wondering what others have experienced with different values and types of the input cap. Also, what is the purpose of the input cap?
I've had good results with a LM3886 inverted GainClone without input cap.... I sounded good, low offset (about 25mV), everything was fine ... untill ... one sad day ... I messed up the powersupply of my preamp .. without realizing that, I switched on the amp ... a big oemmpfffff ... no sound .. until after a minute or so, while I was trying to find what was wrong, suddenly a weird kind of smell appeared and smoke was coming out of my reflex ports ... my woofers where toasted.... a input cap would probably have saved my woofers.. it limits DC-gain to 1...
Goodluck to you 😉 ,
Thijs
Goodluck to you 😉 ,
Thijs
Ehhhhhhh it limits DC gain to zero!! sorry about that ... you were right analog_sa .... yeehhhhhh I was brave, young and stupid... and got some ideas in my head about low frequency group delay etc ect .... actually the preamp was capacitor coupled, but I used it a headphone amp too, so I used a 4700uF output cap ... this had a DC time of 300 seconds or so .. hmmmm stupid... but I've learned.. my newest gainclone uses a 4.7uF input cap ... and it sounds good..too
Regards,
Thijs
Regards,
Thijs
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