Altmann Tera Player - Page 60  

its quite similar to my ackodac + other modules, except the dual ackodac is 4 channel (2 x complete ES9012 dacs) and any external oversampling is done on my computer. I have included everything including their clock supply upgrade, vibrational mounting on the clock, galvanic isolation before a fifo memory buffered 4 x OS synchronous clock/i2s, wifi/ipad remote, -113dB THD+N and 132+dB DNR output with a no global feedback discrete IV stage etc etc

if you are talking about the digital filter, they are using a DSP as I suggested was the better way of doing it these days and they are talking about a separate digital filter and analogue filter. they mention both in the one paragraph, but only in relation to each other. they mention oversampling in the digital filter being beneficial, in that it makes the job of the analogue low pass filter at the output easier. It means it can be further out of the audio band; one helps the other be more effective, but its 2 different parts of the circuit, 2 totally different circuit topologies, one digital, one analogue, one before and one after the dac.

its interesting reading in that it confirms the direction of my build is sound.

but i'm grasping at straws above as to why you linked me, if you simply thought I might find it interesting, thanks! its interesting enough, from an egotistical POV but there is nothing new there, ive had a similar working system for the last 12 months, but with the second pair of dacs and the control systems ongoing. they have infinite resources compared to me, their case will be much prettier most likely, but I havent skimped anywhere, there will be some areas I have outspent them; its been a 2 year money and time sink.

the analogue filter on the output for me is not so important, I tried some on the output and found no audible improvement and opc found no measurable improvement, so I omitted it, there will be some small amount performed by the mosfet capacitance. and i'm using digital DSP on my computer..

dont take me the wrong way above, not meaning to be a dick, just a bit confused.

hey those guys sure know what they are doing

 and you're over simplifying the input comparison. I'm not against D/S DACs and that manufacturer uses them in their less expensive products, with similar though less costly massaging. I'm of the opinion that it's how you use them, ladder or d/s, rather than an either or proposition. At cost no object, the best I've heard use a ladder but that doesn't make it an absolute as many like to deal with here. It's just what I like.

 

What happens in a DAP has little to do with state of the art and involves many compromises. It's also where something like a wolfsen or ES with their VG modern inboard circuits and low power consumption are generally preferred.

 

I also wouldn't assume that Altmann has chosen all the wrong compromises inculding dynamic range and low def for a portable device. I'm actually familiar with a couple of his previous pieces. Like this one, they were also not for me but there was nothing wrong with them. He's into finding novel and simple solutions to complex issues. It's a very nice way to not get caught out. We rarely (never?) know everything that's happeneing in a circuit.

 

oh yeah the 1704 is a nice chip, and I would have loved if the ARTA R2R didnt become vaporware. ive never said anything against R2R or the 1704, ive thought of playing with it but I would just be duplicating hardware. it doesnt tick quite all my boxes, it wouldnt work in my setup, wont do DSD, doesnt have digital volume without external DSP etc. i've generally preferred ESS, but with enough funds and time it would be possible to do much the same thing with the 1704. I would need minimum 6 or 12 x 1704 dacs though $$$ which means MANY more low noise power supplies... more $$$. the final system i'm working on is a pairing of the multiple dacs and multiple poweramps controlled/sequenced with a headless computer, looking like a beaglebone at the moment


sorry not sure what comparison you are referring to? my ESS and the Naim? sure of course, I dont have time for a novel =) the ESS has an internal digital filter that I leverage some of and of course the 1704 is a single channel dac that needs quite some digital filter trickery with DSP or logic/flip-flops to gain the best of.

nothing to argue with there, Accuphase uses the ESS in its top of the line products, totally agree past a point its how you use them, but you cant polish a turd. ladder or SD doesnt really matter to me, I just prefer ESS at the moment and have been given no reason to divert my attentions of the last couple years building this system.

rest answered in PM