Mr Pass...Some crazy ideas for your new amplifier...

[oon_the_kid]

THe ESS Dacs are Vout but are extremely well done. If you want to use the D1, then look at the AD 1865. IT is very highly regarded and used in the Audio Note Dacs. Get a Kit off ebay and change the output stage. From there you can tweak as you like. Take a look at this thread.

http://www.diyaudio.com/forums/pass-labs/190438-ss-120r085-depletion-mode-jfet-3.html#post2603798

Hi,

Thanks for the info. One of the challenge in implementation of this project is the volume control. Since the output of the DAC is now connected directly to a Pass Amp, there are no real means of controlling it. The most logical way is to do it digitally after a 16 bit file is upsampled to 24 bits. But It also requires that the DAC be 24 bit dacs. I just received my AD 1853 DAC from hifimeDIY. Haven't tested it yet, but it could be a vehicle for doing it. Only drawback of the DAC is the output is differential current. Which means I need 2 I/V converters and feeding it to a Pass Aleph J. This sorts of limits the option I have on Pass Amps I could use. Of course I could also use AD 1852 which has a differential voltage out (if I could find such a prebuilt DAC) which has voltage out, but I suspect it is just 2 op amps inside.

Incidentally where could I find the circuit for the D1?

Sorry couldn't make out the thread, what is it for?

Oon

 

[oon_the_kid]

The high dollar ESS dacs can be used either way and most are implementing them for current out.

The PCM1704 might have been the last true 24 bit ladder dac, but I may be wrong about that.

Best, Bill

Thanks Bill,

PCM 1704 looks like an interesting DAC. Its only single channel instead of differential, and it looks to be split supply. which means this one can be paired directly to a ZenI/V and straight to an F5 or something. without worrying about the capacitor coupling.

Thanks will keep an eye out for a cheap chinese DAC for testing.

Another DAC which caught my fancy is the wolfson 8840. I see some cheap chinese kits. They are suppose to sound very good have differential voltage outputs direct from the chip. The twisted pear version is out of stock. But the input could then be fed into a Aleph J. Saving on the IV stage.

Oon

 

[buzzforb]

Hi,

Thanks for the info. One of the challenge in implementation of this project is the volume control. Since the output of the DAC is now connected directly to a Pass Amp, there are no real means of controlling it. The most logical way is to do it digitally after a 16 bit file is upsampled to 24 bits. But It also requires that the DAC be 24 bit dacs. I just received my AD 1853 DAC from hifimeDIY. Haven't tested it yet, but it could be a vehicle for doing it. Only drawback of the DAC is the output is differential current. Which means I need 2 I/V converters and feeding it to a Pass Aleph J. This sorts of limits the option I have on Pass Amps I could use. Of course I could also use AD 1852 which has a differential voltage out (if I could find such a prebuilt DAC) which has voltage out, but I suspect it is just 2 op amps inside.

Incidentally where could I find the circuit for the D1?

Sorry couldn't make out the thread, what is it for?

Oon

Got the threads mixed up. THere is another guy in the Pass Labs forum asking what transistor amp would be most like a SET.