D1 I/V Stage Finished.

After a long time I almost have my boards ready.
I am using till now an Upsampling DAC from Elektor magazine but I want to replace the analog stage because it has opamps with something better.

I made a stereo version of the D1 I/V stage on one board direct for tweaking CD Players and DACs.

My Dac has 2 PCM 1704 and 4 opamps for the I/V and filter stages.

I will be posting pictures later on.

This the PSU.

I use here 4x 11DQ10 Schottky diodes. MKP Wima across them and Panasonic FC caps. The ICs aren´t on the PCB yet.

This is the actual stage with two stages on one PCB. You could actually use it for balanced signal also.

I use the signals singel ended so use only one board.
The Mosfets are missing from the PCB but all other parts are on it.

Silver Mica CAPs for the filter part. Audyn 4,7uF in series with the output. Welwyn 1% low noise resistors. Panasonic FC electrolytics.

I will be posting more info soon.
Gerber files an so on.

The Mosfets are missing because I don´t have the heatsinks yet. Or maybe I will use them without heatsinks. I don´t know yet.

The I/O stage is exactly the same from Nelson Pass´s D1 DAC.

I will be using a small toroid 2 x 30 V / 30VA.

So it´s finished at last. I could only test one channel for the moment because I have to make some changes on the DAC board.

I took the opamps off but I have to desolder a few resistors and capacitors or they will effect the signal.

Setting the DC voltage of the input isn´t so easy and stable as I thought but it stays in the range +/- 10 mV.
Does anybody know how much this should be max. ?

It doesn´t effect the sound though which I can say is super super clear.

I also made a few corrections on the PSU after burning 2 diodes in the bridge. That´s what happens when you try to test it 2:00 clock at night.

I am also waiting to get to bypass caps MKP which are missing there in the middle.
I thought it would be good to parallel them with the electrolytics. The Panasonic FCs that are lying there.

The inputs are at the top of the picture and you can see in the top corners the 2 small trimmers. With these you set DC offset at the input to 0V.

I use the PCM 1704 which has a current output like many DACs and the voltage there must be at 0 Volts.

The outputs are at the bottom where the 2 Audyn Caps are.

I have to find a way to post it in pdf in original size.
I don´t know how yet.
Does anybody here know how to transfer traxmaker files to pdf?

If you want I could order a few board if others are also interested.

A few people have been asking for pcbs.

The reason that I don´t give any pcbs away is that I only made one.
Second the layout isn´t 100% OK. It works very very good but the mounting has a small problem for my box.
The circuit works now for almost one year and I can say I wouldn´t change it. The quality is so clear and dynamic.

If more people are interested I could make new improved boards and give them away at a very reasonable price for DIYers.

Well it doesn´t take long to make a new improved version.
People who are interested in boards should post for how many boards they want.

Each board has 2 stages. That means if you have left right unbalanced you need 1 board and 1 power supply.
If you have left right balanced you need 2 boards and 1 power supply.

About the price it depends on how many boards you guys want and how many I will at the end order.

If a few people are interested I will ask for a price from the manufacturer.

Just keep me posted when someone is interested.

Very tidy and good work for a p2p board.
I have a pcb for a clock from ELSO WKAK on the forum but i have never used it. Is that from guido? Is it the same person?