Tonight I had a chance for a first time to listen DAC through its opamp buffered outputs. Absolutely no go for me. Very different from SE unbuffered outputs. Where sound was soft and warm on SE it was harsh and metallic through buffered outputs. If you did not try SE raw out, you have to give it a try. A great difference. One could buffer that output through passive jFET buffer, but in my case it did not call for it. Straight to amp works fine in my case. For analog volume control I would say passive buffer should be definitely considered. But absolutely not through opamps. This DAC sounds really good and it is crime to loose it with opamps.
I came across this comment: "Can also take an external +/- 7-15V DC supply.". However examining the headers, its unclear where these would need to be connected. Has anybody tried using a DC supply? I'm thinking, if the dac only draws 2.4W a smallish size battery could make this into a portable.
You connect the DC to the AC inlet. Yes. Polarity don't matter. +00- or -00+
I run it on 2x12v 7AH batteries.
//
ok, cool, thanks on the heads up on using a battery.
I have two more questions I hope someone can answer.
I see there is a I2S "FSEL in" pin (Selects between 45.1584 MHz and 49.152 MHz) how does this work? Can we make this switch on the I2S MCLK out pin, by going Hi (3.3v)/ Lo (GND)? In which case the BBB Miero driver might become an option.
How does the I2S MCLK out pin "divider" option work?
I have two more questions I hope someone can answer.
I see there is a I2S "FSEL in" pin (Selects between 45.1584 MHz and 49.152 MHz) how does this work? Can we make this switch on the I2S MCLK out pin, by going Hi (3.3v)/ Lo (GND)? In which case the BBB Miero driver might become an option.
How does the I2S MCLK out pin "divider" option work?
)My experience as well. I am working on a jfet test board and a 2nd design for tube test board. I did not like the first tube buffer I tried but it was a poor tube choice for this application.
I have used opamp DAC outputs before and liked the results (MHDT Paradisea) but when I A/B the output stages on the DAM it is no contest. Direct is the only way that has the magic in my system!
I use them for stereo subs and sounds great. That being said, be aware that changing filters seems to change the bass response from the buffered output. Some settings are great for bass (like loudness), some are flat, and some shift the frequency response emphasis up to the 1-5khz range.
I have tda1541a (NOS) and pcm63p (*8 OS) all with similar linear AC power. Honestly the DAM is a chameleon depending on the filter choice. The pcm63p doesn't get any play time anymore. The TDA1541 is still in rotation since the NOS filters for the DAM are still being worked out in the filter brewing thread.
The pop problem isn't a big deal if you just leave the dac on or mute your system before turning it off.
The 625 ohms is only the impedance comming from the DAC-ladder. The source that feeds it has also an impedance. From the charging C135 data from here
I would estimate an 1600 ohms equivalent resistance in series (of an ideal voltage source).
Has that impact on the roll-off frequency of the final analog filter?
Can someone please point to the filter brewing thread? I cannot find it...