As for the SQ...
The beneficial 2nd harmonic predominant spectrum provides piano with real body.
Voices are quite natural with no hint of 400hz grunge.
Cymbals are vivid and extended in the higher frequencies.
Microdetail rendering is outstanding so I can hear low level information easily even when it is buried under louder instruments playing in complex orchestral pieces.
It sounds BIG without any signs of edginess or stress.
Hope someone wants to build it so we could compare results.
The beneficial 2nd harmonic predominant spectrum provides piano with real body.
Voices are quite natural with no hint of 400hz grunge.
Cymbals are vivid and extended in the higher frequencies.
Microdetail rendering is outstanding so I can hear low level information easily even when it is buried under louder instruments playing in complex orchestral pieces.
It sounds BIG without any signs of edginess or stress.
Hope someone wants to build it so we could compare results.
SR improvement
Latest modification regarding SR.
Searching to improve SR hoping it would give a better bass response I found that increasing the collector resistor (R12) on the VAS beta enhancer (Buffer) did in fact reduce SR.
This resistor is there to limit dissipation in this buffer but when it's value is larger than 7kohm, SR is impacted.
To easily study SR evolution I used the LT_Spice function d() that produces the derivative of the chosen visualized curve.
Here d(V(vout)) produces a curve that indicates the slope of vout.
I am simulating a square 20khz wave for this purpose and d(V(vout)) shows the max SR to be 103V/us
I replaced the initial 12kohm by a 2kohm resistor as R12 and added a small heatsink over the BC556B... and guess what.... bass is now more "pinched" with more detail and apparent speed.
Latest modification regarding SR.
Searching to improve SR hoping it would give a better bass response I found that increasing the collector resistor (R12) on the VAS beta enhancer (Buffer) did in fact reduce SR.
This resistor is there to limit dissipation in this buffer but when it's value is larger than 7kohm, SR is impacted.
To easily study SR evolution I used the LT_Spice function d() that produces the derivative of the chosen visualized curve.
Here d(V(vout)) produces a curve that indicates the slope of vout.
I am simulating a square 20khz wave for this purpose and d(V(vout)) shows the max SR to be 103V/us
I replaced the initial 12kohm by a 2kohm resistor as R12 and added a small heatsink over the BC556B... and guess what.... bass is now more "pinched" with more detail and apparent speed.
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