M49C circuit details / questions

[OneRoomStudio]

The "treble cap" is indeed audible. The LPF in your graph already starts between 2-3k.

This cap works well with AC701 since it has a very detailed and excited top end. Other tubes can sound very dull and dead with it.

It does start at 2-3K, but it's very shallow. It's only down <0.5dB at 20K. At 10K, it's down less than 0.1dB. You must have better ears than me to hear it.

 

[pasarski]

It does start at 2-3K, but it's very shallow. It's only down <0.5dB at 20K. At 10K, it's down less than 0.1dB. You must have better ears than me to hear it.

I definitely couldn't hear that. But it introduces some distortion, especially at high frequencies, that could be heard.

 

[tomas.borgstrom]

It does start at 2-3K, but it's very shallow. It's only down <0.5dB at 20K. At 10K, it's down less than 0.1dB. You must have better ears than me to hear it.

I’ve experimented a lot with this. Our ears are very sensitive. (BTW I’m not a hifi golden ears guy. I’m very critical and I know that our brains can easily fool us).

I definitely couldn't hear that. But it introduces some distortion, especially at high frequencies, that could be heard.

I agree, a low pass filter is not the only thing that is going on.