Gertjan wrote: ↑
Sun Jun 01, 2014 12:12 pm
Here are the diagrams. These are the things that keep me up at night.
Sorry if I repeat myself.
I keep changing my mind about whether L2 belongs on the input or the output, trying to rationalize either way. Is one way preferred to the other?
I saw where you mentioned the wye may be out of favor for not being the absolute lowest inductance approach but the thought of impedance imbalance from the non wye approach is giving me a headache. That got me obsessing over whether I could come up with an equivalently low inductance wye solution to the preferred lower inductance non wye configuration and get the benefit of the wye without giving up RF performance.
If the inductance will be at a minimum when the path (RF path through the filter cap) is as direct as possible to the chassis, and the gap between the pin being filtered to it's metallic connector body represents the shortest path possible, if the physical size of the wye configured filter caps is smaller than than that gap, then the inductance of a wye may not be much higher than the lowest inductance approach, correct? There are just a few millimeters from, for example, pin 2 and pin 3 to their respective connector shells. I have very short axial lead beads soldered right to the pins. I believe if I could only find a way to fit some wye configured surface mount parts in there and find a way for the caps to make good electrical contact with the chassis tied connector near the pins, the inductance would be as low as is possible and I wouldn't be giving anything up by going with the wye in that case.
Though I am also concerned about using ceramics here. I understand they may be shunned by audio guys. Would the damage still be bad if the capacitors in these filters were ceramics considering their low capacitance values? The inductance for ceramic caps is extremely low and they would probably excel in the job of filtering but I'd reconsider if they would ruin the sound.
mediatechnology wrote: ↑
Thu Jan 25, 2018 8:24 am
Aren't your 124X in the same box as the flat preamp?
In my case the inputs are the instrumentation amp on the Flat Phono PCB. The outputs the THAT1646 from the RIAA eq switcher record and monitor paths. I am assuming the LC configured filters on the inputs and the CL's on the outputs are still applicable in my case.
I went back to a single THAT 1240 on the output of the Flat Phono pcb and removing the optional input THAT1240's from the input of the RIAA eq switcher pcb.
I tried warning you about my juvenile questions before I joined the board, Wayne.
You still invited me in here anyway.