discrete I/V converter for dynahi output stage - should this work?
Jun 13, 2004 at 8:42 PM Thread Starter Post #1 of 5

Glassman

Headphoneus Supremus
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hi, I've been thinking about using some current output DAC with dynahi, this design is simple, current from the DAC's outputs (balanced) is injected to the emmiters of the input transistors T5, T6, this point is kept on ground potencial using T3, T4.. T1, T2, LED1, LED2 and R1, R6 are current source and current sink, servo point works exactly like in kevin's amps, balancing the voltage of the midpoint between the LEDs changes current flowing throuh them and this affects voltage across them.. OUT_A and OUT_B should behave exactly like correspondings points of the input stage in kevin's amps..

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might this actually work? and why not
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thanks!
 
Jun 13, 2004 at 9:03 PM Post #2 of 5
Try it and find out. You still will need an anti-aliasing filter however.

I did try something like this once without the filter just to see how
it sounded, and it sounded REAL BAD.
 
Jun 13, 2004 at 9:12 PM Post #3 of 5
wow such a fast answer
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hmm I thought -100dB stopband up to some 150kHz at least will be enough, guess I was wrong.. can you tell me more about your trials? is there some really good way to do I/V that can be directly interface to the output stage of dynahi?
 
Jun 14, 2004 at 12:10 AM Post #4 of 5
Quote:

Originally Posted by kevin gilmore
Try it and find out. You still will need an anti-aliasing filter however.

I did try something like this once without the filter just to see how
it sounded, and it sounded REAL BAD.



I am listening to one of those TDA 1543 based nos dacs at the moment,
sounds pretty nice actualy..

I would definitely recommend trying one 'just to see' , I have been pleasantly surprised.


Setmenu
 
Jun 16, 2004 at 1:52 AM Post #5 of 5
Quote:

Originally Posted by setmenu
I am listening to one of those TDA 1543 based nos dacs at the moment,
sounds pretty nice actualy..

I would definitely recommend trying one 'just to see' , I have been pleasantly surprised.


Setmenu



The TDA1543 NOS DAC really sounds nice, I am constantly comparing mine connected to PPA with a portable diskman, DVD, NAD 523 CD changer. It's the smoothest, most pleasant sounding one beating all them, IMHO.

For a descrete I/V stage, I'm considering LM6172 and LM6171(virtual ground) chips. AOS uses them for his DAC too and it's one of the 'cranky' chips. Also seriously considering THS4082/81 chips which are very highly(if not the best) rated at another forum that I visited recently(in russian)http://www.hi-fi.ru/search/index.php...top&q=THS4062+ .

THS4082 is dual one and consumes half of power than the THS4062 one.

I'll get them from Texas Instr. in a couple of days and will post my results.

Anyone tried THS4081 or THS4061 yet?
 

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