Dual TDA1541 Dual balanced DAC PCB (batteryman)

[sbelyo]

@batteryman I get it now... I'm a fan of his boards so I'll try this route. Can you take a pic of how you connected it to the DAC board? I just want to try to understand how it feeds both of the chips at the same time.

Thanks

 

[batteryman]

It's simple. The PCM board has 4 data outputs, L+, L-, R+, R-. The clock and latch (WS) are common to both because the dacs are in simultaneous mode so all data is latched at the same moment.

My messy wiring is embarassing!

 

[sbelyo]

Thanks, I see... I thought I needed to use something to split the signals. I think I can make out how you connected everything.

 

[batteryman]

Ian's board does it all. Just input I2S and connect to your balanced dac, TDA1541, AD1862/1865, PCM etc.

 

[sbelyo]

@batteryman Have a look at this board

https://www.aliexpress.us/item/3256803864200243.html?gatewayAdapt=glo2usa

 

[batteryman]

Thanks, but no use as it doesn't provide -ve L & R data for dual DACs.

I know you can just invert the data and put up with the LSB error at very low levels.

Also no mention of the clock being stopped after the data is latched - that's a very important feature for low noise, and whether it provides the offset binary needed for simulaneous mode.

 

[sbelyo]

oh well, it was worth a shot

 

[sbelyo]

I just realized on the bottom of ian's board there's another set of ufl pads for the common connections. I bought a handful of ufl pigtails to see what I can put together.

 

[batteryman]

I started to alter my pcb for U.fl connectors but wasn't able to finish it and also incorporate Grundig's dem clock method,

 

[sbelyo]

I think those a great additions. I'm in no rush so let me know if you finish that. I will wait

 

[batteryman]

I might redesign it so IanCanadas I2s-PCM board can be fitted to the dac pcb so the Ph2 cable can be kept very short.
Also remove the voltage regulators to save space.

To use the Grundig or even a divided Bck dem clock this would have to comre from the input to the I2S board as the clock is stopped after the latches are set.

 

[sbelyo]

Based on what I've read, I think all those changes would be worthwhile for sure. I'd say I'm two months away from finishing my workshop and being able to construct stuff but I'm certainly willing to test.

I was planning on leaving out the regulators to start and just feeding the board directly with Salas BiB 1.3 supplies since I have all the parts

I've also got 3 years of Audio Amateur magazine on the way that has some articles on the 1541 and a DAC layout. I'll scan some copies for you

 

[sbelyo]

I built an external DAC psu which uses two banks of 5 cells, in a separate housing, with taps after 2cells for the +,-5v regulators & after all 5 for the -15v.

They are 8000mahr so don't need recharging too often but I do have to remove them and charge two at a time in separate Li-ion compatible chargers. (they are 22650 cells which are too large - the charger is meant for 18650 cells and could charge 4 of them at a time.)

I bought a multi cell charger / BMS with sensors for each cell but haven't fitted it yet. It would avoid the need to charge them outside of the DAC psu.

Quick blow fuses provide short circuit protection.

Did you ever get around to fitting the BMS?

 

[batteryman]

Not yet. Might be months before I get to it.

My battery module has a pair of +- 30v led voltmeters. so I can keep an eye on them.

 

[sbelyo]

I'm game to try so I was surfing Aliexpress and came across them. I'll see if I can find some youtube videos