DIY nos TDA1541 tube DAC

I uploaded this old school DAC project in my blog today.



I started with a generic TDA1541 board from eBay, bypassed the SAA7220P filter chip, replaced the op-amp analog section with vacuum tubes and tuned it to my ears' content.

More details here.

 

Great blog post, thoroughly enjoyed it.

 

Thanks for the kind words!

Wishing you a great holiday!

 

I have been wondering if this may be worth attempting with the more commonly available TDA1543 dac?

 

I did a tube buffer for the $30 TDA1543 board to the right. I couldn't go beyond a buffer because the output of that DAC chip was almost line level. I've read that there's a way to lower the output, but it's beyond my abilities.

 

i think i have a valab nos 4x1543 lying about - it had some weird crackling issues which I believe is common for them to develop - so changing out the output might be a fun experiment at some point in time

 

I just have a hunch that the output can also be reduced by using a much lower value I/V resistor than the 1k currently installed. Maybe I'll try using a 100 ohm or lower value just like I did with the TDA1541 one of these days...then add a tube gain stage.

Anyway, if you discover anything, let us know.

Thanks!

 

Use a continuity tester on a DMM to check the 1k resistors, if one end is connected to the chip outputs and other end to ground this is the I/V resistor.
1k is very high and I did not like the sound much using such a high value for the TDA1387, as far as the DAC chip is concerned you want keep this value as low possible for best subjective and measured performance and make up the gain with an amplifier after.
Of course an amplifier wont be able to provide infinite gain for free so you'll have find the balance that sounds best, 100 ohm is a good starting point for IV, should be very little to no loss of quality from DAC and output levels are not too low.