Hi all,
Sorry if this has been already discussed but I could not find much info on the implementation of the analog filter of Adagio:
1) What are the RLC values of the double T filter: 70mH+1nF+?R, 70mH+47k ??
2) Has anyone implemented it? What chokes have you used? What core type? What DCR?
3) The gain seems huge or I'm missing something? 1:15 transformer then E182CC SRPP gives amplification >300 Or the filter chokes have a big DCR?
4) How exactly is the filter tuned including the parasitic components? How does one retune it? I'd be interested in a better transformer.
Thank you,
Jarek
Sorry if this has been already discussed but I could not find much info on the implementation of the analog filter of Adagio:
1) What are the RLC values of the double T filter: 70mH+1nF+?R, 70mH+47k ??
2) Has anyone implemented it? What chokes have you used? What core type? What DCR?
3) The gain seems huge or I'm missing something? 1:15 transformer then E182CC SRPP gives amplification >300 Or the filter chokes have a big DCR?
4) How exactly is the filter tuned including the parasitic components? How does one retune it? I'd be interested in a better transformer.
Thank you,
Jarek
I've not tried it but I've been running similar LC filters for a very long time on the output of my DAC chips (not TDA1541A). I downloaded the schematic for the Adagio but the component values didn't display clearly enough to answer your specific questions.
What aspect of the transformer do you consider needs improving and which one are they actually using?
What aspect of the transformer do you consider needs improving and which one are they actually using?
Hi,
I don't like the Loesch analog approach, would test a 6 db filter (for nonoversampling TDA1541A). The SRPP is a high gain-high distortion circuit.
I don't like the Loesch analog approach, would test a 6 db filter (for nonoversampling TDA1541A). The SRPP is a high gain-high distortion circuit.
First of all I'd like to know if this 3rd order filter is at all needed. As I understand it will produce a near perfect amplitude curve at the cost of screwing up group delay. Have you tried your DAC with and without it?
Second the TX used is Amplimo TM-3 with rather poor bandwith (30-25k @-3dB). I'd like to use e.g the Sowter 1465.
Cheers,
Jarek
I'm not following you - 'a near perfect amplitude curve' ? No DAC analog filter that I've seen comes anywhere near to a 'perfect amplitude curve' - only digital filters can do that. Yes the filter introduces some phase distortion at HF.
Yes I've tried both with and without filter, with filter always wins - more holographic presentation with lowered noise floor, better stereo imaging.
I will check out those trafos you mentioned.
Yes I've tried both with and without filter, with filter always wins - more holographic presentation with lowered noise floor, better stereo imaging.
I will check out those trafos you mentioned.
Hi,
Want to build this filter as well but can't find the 75mH coils...
Anybody has an idea where to buy these coils?
Thanks in advance.
Ad.