Less simple I/V for TDA1541

[rbroer]

The result

[rbroer]

Some components on the bottom

[rbroer]

And the schematic

[jean-paul]

How does it sound, Rudolf ? I mean when compared to your previous designs.

[rbroer]

Sorry for the schematic to be rotated, it wasn't accepted and I lost detail when trying to resize.

I started off with complementary feedback pairs for all transistors.
I made sure the local feedback loops where very small by placing transistors on both sides and using 805 1k SMD resistors.
Didn't workout though, lots of noise. So I ended up with the circuit as posted.

All capacitors are Rubycon ZL series.
All transistors are 2SC2547E and 2SA1085E, except for the power supply (ZTX960B and ZTX790A).
The 100 ohm resisors for filtering the references are all 805 SMD's on the bottom side.
Riv is made up with 1.5K RikenOhm and 10k DALE RN65C.
The Civ is 2nF Philips KP
All references VRx are TL431's (2.5V) the PNP has two red LED's

I'm using some OPA627 for the DC servo, bit overkill, but had not been using 'm ever since I stopped using opamps as I/V converters. The integrator capacitor is on the bottom side, I used a 100nF ERO KP capacitor. Earlier I tried a Blackgate 0.47u/50V NX-HiQ but that leaked too much, resulting in too big an offset.
Pot R2 is adjusted for 0Vdc, the DC servo catches any drifts between ca. +/-150mV
Pot R1 is adjusted for 0Vdc on the DAC outputs.

I'm using some weird resistor values, just happened to be the DALE's I had available. 180 ohms for the 1st current sink and 820 ohms for the second current sink should work just fine.

R11, R6 and T9 are a cascode on the 2nd current sink, they could be omitted. My simulator tells me it does zip for THD. I had them already in, so didn't bother taking them out.

Finally the sound:

Incredible, finally I prefer my TDA1541A-S2 player above my TDA1543 player. Transparency has increased a lot compared to the single ended version of this circuit (see simple I/V threads).
It is amazing how much detail comes out now

I've got another board, that includes TDA1543 as well, with power supplies, reclocking, Tent XO. Hopefully will have it finished in a couple of weeks.

Is sent Peter Daniel the same boards, hopefully he has got something to add to this thread very soon (I'm quite sure...)


Happy building.

[Audiofanatic]

Hi Rudolf,

I looks nice!
The sound? Better than the one before?

BTW, did you use DALE and/or Riken ohm's?

Please tell us more.


Regards,


Audiofanatic

[jean-paul]

Mmm, could it be that the integrator cap is missing in the schematic ?

[zygibajt]

Great thing.
Is it intended for non-os or os TDA1541 mode?
Also ,any substitute for 2SC2547?
I had a very hard time finding them for some other project some time ago.
Bartek

[Peter Daniel]

I got some BC547 and 557. Would those be good enough?

The stage can be used with both oversampling and non-oversampling.

[mdlover]

nice work, Rudolf!