[Glassman]

I'm thinking about designing some very nice DAC, I'll be using PCM1798, which has current outs and I'd like to know what are possible ways to do I/V conversion..

passive - resistor to ground

active - opamp w/ feedback resistor

???

you can list advantages and disadvantages of each method too..

thanks for tips guys (& gals if Morsel's 'round

)

 

[gsferrari]

I -> V conversion eh...

1] Series resistor with output across it. You can use a POT to vary the output. This is a lossy method if there ever was one

2] Use an inverting amplifier circuit...use Op-Amps or BJT's... This is a stable voltage source and you can get higher output with gain settings...

3] Combination of 1 and 2 with a op-amp buffer. Direct negative feedback from output and vin = v out but this is a current isolated circuit...you can draw high voltages without large current draw...perfect for those Sennheiser Headphones

Im no expert

but are you considering building an amp to go with the dac? If you are then keep me posted on the design ideas that you have...I am interested in making one myself...

Also - what DAC method are you using? Successive approximation or asymtotic convergence? What about Jitter ?

cheers!

 

[rickcr42]

current feedback opamp to a 1:1 transformer and finally on to a tube output stage

Mosfet or JFET , again transformer coupled

 

[Glassman]

Quote:

Originally posted by gsferrari but are you considering building an amp to go with the dac? If you are then keep me posted on the design ideas that you have...I am interested in making one myself... Also - what DAC method are you using? Successive approximation or asymtotic convergence? What about Jitter ? cheers!

idealy i'd like to end up with balanced voltage outputs that will connect to the gilmore's both inverting and non-inverting inputs.. i don't need volume control in analog domain since it will be used paired with computer..

huh! jitter is the only word i understand from the second paragraph

jitter should be non-existent in my dac since it will be master, soundcard which will feed data into DAC will operate as slave.. i'll be using either Tent's XO1 or Kwak Clock placed near the DAC chip itself..

also, cheers

I've been thinking about some tricks with OTAs like OPA660 or AD844 as seen in various threads on diyaudio.com.. like here: http://www.users.verat.net/~pedjarog...a1541a_dac.htm