Reconstruction filter from "Opamp applications" (Jung)

[00940]

Did anyone ever tried the reconstruction filter described in the chapter 5 of this book ? (the book is available for download here : http://www.analog.com/library/analog..._handbook.html )

It is on page 5.126. It is a 7th order filter, using 6opamps/channel, in a shunt configuration. Does this topology offer so much advantages it is worth the time and money to do it ?

[peranders]

I have asked myself the same question. If you search for FDNR you will find some more.

In theory most filters are the same but not in real life. Bob Pease has made a good webcast show at National.com about active fiters. He shows how different topologies behave.

In litterature there are not much about the "fidelity" of different kind of filters.

[00940]

You're right, some interesting stuff. If only I hadn't searched only in "digital"

[X.G.]

hi,

I had tried two type of LC steep filters with freq equalizer for TDA1541 NOS DAC...one is 5 pole 2 zero elliptic filter,another is 8 pole,3 zero elliptic filter.... the sound is much much better than before.

the post which I analyse the NOS DAC in Chinese is on here.
http://www.hifidiy.net/dispbbs.asp?b...D=12780&skin=0


my TDA1541 NOS DAC with steep LPF VS krell SBP-32X DAC

re-draw the I/V sch of Krell SBP-32X DAC



the I/V sch of my TDA1541 NOS DAC before I optimised ,which LPF is 8 pole,3 zero elliptic filter


the respone of my 5 pole 2 zero elliptic filter

[peranders]

Impressive work.

Interesting that some design a really complicated filter which they claim "sounds good" and some don't use any filter because any filter "sounds bad"

[janneman]

Originally posted by peranders
Impressive work.

Interesting that some design a really complicated filter which they claim "sounds good" and some don't use any filter because any filter "sounds bad"

P-A,

Don't tell me you are *really* surprised by that! (Hint: see my sig).

Jan Didden

[peranders]

Your sig is right on target but when it comes to me, I can say this much that I'm not dissapointed with my things but I'm sure someone find them as "bad". Compare how my SMD Gainclone got tweaked unheard and the result was amazing... unheard. This confirms your claims

There are two different things:

1 Be pleased with your results

2 Know what you have achieved compared to other designs, seen from the objective perstective.

[janneman]

Originally posted by peranders
Your sig is right on target but when it comes to me, I can say this much that I'm not dissapointed with my things but I'm sure someone find them as "bad". Compare how my SMD Gainclone got tweaked unheard and the result was amazing... unheard. This confirms your claims

There are two different things:

1 Be pleased with your results

2 Know what you have achieved compared to other designs, seen from the objective perstective.

I need to come out now: 90% of my pleasure in diy audio is completing an interesting - from an engineering pov - design that was difficult and something not normally done. And yes, of course, it always sounds great!

Jan Didden