gainn stage for tda1543 dddac fet?

[spgjmf]

hi folks,
I have built doede's easy usb dac with the 2707 and tda1543 dac chips. The output of the 1543 is too low for my whee little amp, 6em7 SE...the 2707 drive ut fine, but the 154 needs more output.

I would like a gain stage which could use the 12vdc supply as the kit already uses....maybe somethig using fets, ( i have some 2sk170) . op amps are ok too, just they need dual supply or Vert grd.

I trired the simple opa2604 stage as suggested in the app sheet, but only got a tinny am radio sound...no bass. anyway any suggestion or cicuits to bring the 1543 output up to a higher level would be great. like I said simpel fet preamp would be great.

btw - the dac kit is an easy build and the 2707 sounds darn good too, great detail. now if I can only hear NOS dac...

thanks for any suggestions,
Jeff

 

[Zen Mod]

you can implement this one , or Papa's Jfet BOZ , whatever ;

looking at pic - just toss input pot , and place cap on output .

for values for 2SK170 - search for Papa's Jfet BOZ .....

cap multiplier is pretty important here , even if used one is most generic .

it will work , better or even better on pretty much every voltage from 12 to 30 V

in case that you're looking for more advanced circ ...... just say so

 

[spgjmf]

Thank Zen Mod.

I like the jfetBox so much I built one this afternoon.
I added a 0.47uf cap on the src to add a little brightness. oh, and the src res. is 10 ohm.

I realy like it, it matches well wit the tda1543 dac. Gota love the nelson PAss stuff....oh and I think I am hearing the macic of NOS dac. new stuff appearing in different songs.

thanks again - it was very enjoyable to get working and build -
thats what DIY is for. so now I have usb dac to jfetBoz to 6em7 amp driving fe103 speakers. simple diy which sounds great to me.
lm1875 next ...

here is a pic of the build.

best,
Jeff

 

[spgjmf]

just wanted to follow up.
I built a jfet BOZ and have put this and the dddac1543 in a small case. I added a volume pot between the dac and the boz. The output of the pcm2707 is too hot and needs taming when running thru the boz.

I really like the simple boz and intend to build a few more. The 5143 is really nice, laybacked and not aggressive. the 2707 on the other hand is very dynamic and fast(?). both have their places in the listening world.

here a pic of the set up. still need to finish it up, but at least the clip leads are gone.

best,
JEff