Has anyone had any experience with the Rohm BD34301EKV DAC chip?
In the SMSL D300 DAC the signal levels of the Rohm BD34301EKV +/- outputs are not the same! Not only between the two channels, but also the signal levels of the inv/noninv. outputs within a channel are different! Therefore, the more DACs, the more different component values have been implemented according to experience. (https://www.audiosciencereview.com/...s/smsl-d300-review-balanced-dac.28919/page-20) Is this normal behavior for a DAC chip? Especially since Rohm defines this chip as a flagship!
Thank you for your attention! Dee
In the SMSL D300 DAC the signal levels of the Rohm BD34301EKV +/- outputs are not the same! Not only between the two channels, but also the signal levels of the inv/noninv. outputs within a channel are different! Therefore, the more DACs, the more different component values have been implemented according to experience. (https://www.audiosciencereview.com/...s/smsl-d300-review-balanced-dac.28919/page-20) Is this normal behavior for a DAC chip? Especially since Rohm defines this chip as a flagship!
Thank you for your attention! Dee
Yes, sure.
BD34301, also BD34352.
Not, of course, this is a problem of SMSL, and not of the Rohm chip.
P.S. BTW, For balanced output, only differential signal is important (V+-V-), so it might be a different voltages at + and -?, also between the channels, if the differential voltage is equal.
Alex.
So? A small differential DC offset can be removed after the differential summing stage with cap coupling, or by other means.
That said, I have a BD34301EKV eval board here which I was never really very happy with. Eventually I abandoned dac chips and went to discrete resistor DSD dacs with hardware and or software conversion of PCM to DSD. IMHO that's future of good dacs at least for the next while. Its basically how Bruno Putzeys's Mola dacs work, and how high end dacs from Luxman and Marantz are made today. Moreover, there are open source and or freely available projects in the forum to build such dacs. There are gerbers and schematics, etc. No reason to bother with consumer dac chips anymore if you don't want to.
That said, I have a BD34301EKV eval board here which I was never really very happy with. Eventually I abandoned dac chips and went to discrete resistor DSD dacs with hardware and or software conversion of PCM to DSD. IMHO that's future of good dacs at least for the next while. Its basically how Bruno Putzeys's Mola dacs work, and how high end dacs from Luxman and Marantz are made today. Moreover, there are open source and or freely available projects in the forum to build such dacs. There are gerbers and schematics, etc. No reason to bother with consumer dac chips anymore if you don't want to.
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"...and how high end dacs from Luxman and Marantz are made today."
Not quite.
Luxman's topol SACD/CD player (D-10X) uses exactly the same Rohm BD34301EKV chip (x2) as the S.M.S.L D300.
Not quite.
Luxman's topol SACD/CD player (D-10X) uses exactly the same Rohm BD34301EKV chip (x2) as the S.M.S.L D300.
In my understanding, Bruno's DAC doesn't use DSD, rather PWM clocked at 100MHz. The FIR output filter is still part of the design though.
From Mola Mola's site :
The converter is a two board stack that fits into one of the option slots in the preamp. On the first board, all incoming digital audio is upsampled to 3.125MHz/32 bits and converted to noise shaped PWM. On the other board are two mono DACs, in which a discrete 32- stage FIR DAC and a single-stage 4th order filtering I/V converter, convert the PWM into analogue with a breathtaking 130dB SNR.
https://www.mola-mola.nl/dac.php
We call noise-shaped PWM by various names. Quasi-multibit DSD is one. MarcelvdG has talked about how it works. Its an approach to DSD that doesn't need RTZ to avoid ISI (inter-sample interference). HQ Player has such a modulator too, AMSDM 512+fs, which can only be quasi-multibit to work with a DSD dac.
Something like this:
Something like this:
Yes, no, and or sorta. IOW, some do some of the time, either with or without RTZ. In DSD the data signal just tells the dac when to close or open a switch for each channel. The dac doesn't know how the data signals are generated, be it via DSD or PWM sigma delta modulation (except maybe when a dac includes its own internal modulator). The dac averages out the switch on/off outputs and LP filters them to produce audio (kind of like class-D). Whether or not RTZ occurs depends on the particular dac design and or its present configuration. Even with RTZ, it looks like PWM operation measures a little better with Marcel's latest dac design.
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