discrete dac mock up

[yeo]

hi guys

check out my latest article on the site on the discrete dac.

comments?

yeo

[86Ivar]

Looks cool. How is this project going?

Im thinking of doing one to, 16 bit. But finding or matching resistors will be painful.
Ive done some calculations; Resistors tolerance is approximated by a gaussian distribution curve, so if i buy 5000 0,1% resistors i should be able to get a series of 120 resistors within 0,001% if i can find a way to measure them :S Another problem as i do not have that equipment.
I will also get other matched series, but with smaller numbers of resistors. Hopefully someone would be interested in buying...

What kind of resistors do you use? I persume if you use low values you dont need a preamp.

[yeo]

hi

yes, the resistors is quite a pain. if you want to hand match them, you need proper equipment, or at least a good enough fixture to get the desired accuracy. don't forget, even at 0.01%, we are talking about 14 bit accuracy...

anyway, i got it singing 2 weeks ago, been tweaking it to improve its sound. really like what i'm hearing now.

supposed to get production pcb in the last week of the year. it has another tweak in it so the sound may still be improved further!

will see how it goes then...

yeo

[yeo]

hi guys

here's a teaser before i write up the article.

still waiting for one or more components...

yeo

[CKL]

Great! 

[ole]

I really like this one.  Hmm...how about a DAC using tubes for switching? 

Ole

[yeo]

hi ole

that would be terrible! let's see, for 24 bits, we'll need 24 tubes. for stereo, 48 tubes!

good thing is, with a suitable output transformer, may be able to drive speakers directly!

yeo

[CKL]

Hi Yeo,

What is the total current? Could we use battery?

 

[yeo]

hi ck

i haven't measured the current but it isn't high at all. you could use batteries but honestly, i won't bother.

yeo

[kkerwin]

very cool.
k

[ole]

hi ole

that would be terrible! let's see, for 24 bits, we'll need 24 tubes. for stereo, 48 tubes!

good thing is, with a suitable output transformer, may be able to drive speakers directly!

yeo

Hi Yeo!

Not that many, I think - using double triodes just 12, or with triple triodes (e.g. 6MD8 like they were common in color TV) only 8, plus another double triode for channel switching (stereo). Sounds manageable.

Ole

[CKL]

Hi Yeo,

I post the photo to our local forum. Someone has asked about what DAC chip is used? 

[yeo]

hi ck

tell them there is no dac chip there. it's entirely made of discrete components..

msb's dac are all ladder types if i'm not mistaken.

btw, now using a 50va transformer. wow! the dynamics!

yeo

[milen007]

Hi yeo

Is this available as kit?

Would love try it

Erwin

[yeo]

hi erwin

i may offer a built up pcb module. no point in putting out a kit. too many components to solder and mostly surface mounted!  necessary, imho, to maintain the shortest path possible.

my main problem is pricing.

yeo