When you play a 384 kbps file, no filters are engaged at all. To play my filters, you need to play 44,1 (48?) files in "linear" mode. all other modes and Fs, other filters are used (or none).
My filters incorporate an 3 dB attenuation to facilitate "inter-over" protection, so your observation is correct. Thats how it is.
//
My filters incorporate an 3 dB attenuation to facilitate "inter-over" protection, so your observation is correct. Thats how it is.
//
I finally tried the unbalanced output, using a high quality 1:1 output transformer (very linear beyond 100 khz), terminated by 10K.
Sound is much more musical vs. the op amp. I went through a lot of the filters with it again and really love the NOS filter, even at 44,1k and without any corrective circuitry. Plenty of high end for my very revealing studio monitors. Great dynamic, alive sound with a punchy bass, defined midrange and an awesome sound stage.
Everything else sound varying degrees of bland and artificial. 128dp is second best, the linear filters sound dead, boring and stressed.
Still, I wonder if things can really be all right without a low pass filter taking care of mirror images...
Sound is much more musical vs. the op amp. I went through a lot of the filters with it again and really love the NOS filter, even at 44,1k and without any corrective circuitry. Plenty of high end for my very revealing studio monitors. Great dynamic, alive sound with a punchy bass, defined midrange and an awesome sound stage.
Everything else sound varying degrees of bland and artificial. 128dp is second best, the linear filters sound dead, boring and stressed.
Still, I wonder if things can really be all right without a low pass filter taking care of mirror images...
Sorry, no. I have your latest set installed and switching from NOS to the linear filter (correcting for the difference in amplitude, of course) things just sound off. This is in a fully treated studio room with closed box monitors and a rather minimalist signal path.
I didn't like NOS much via the op amp balanced outputs, but other filters sound better via the transformer out, too.
Since my studio amplifier has a balanced input that's what I'm feeding it. Of course, the signal gets debalanced inside by a 5532 again, but that's what the circuitry was designed for.
So I never tried "not having anything".
The audible difference between the op amp output vs. the transformer output is quite clear. The measured difference in terms of frequency response and distortion isn't, but I couldn't get the two recorded sweeps to null properly, so I'll have to look into phase response some time.
I just auditioned the op amp output again with the NOS filter. Don't like it, sounds glassy and brash. Either the op amp on DAM1021 doesn't do well with the mirror images or the transformer filters them in a way that makes the signal more digestable for the power amp input.
Or maybe the transformer and the NOS filter just work very well together for my ears.
Got to do more measurements...
Just imagine the improvement you would experience if you remove both the 5532 (shock, horror) and the transformer. When i think about it i really envy you
