A New Take on the Classic Pass Labs D1 with an ESS Dac

[qusp]

Owen, you could satify both requirements by having a hole drilled in the PCB at the point the screw for mounting it would be when the device is bent to mount on the floor, not off the side, but underneath. or like I do, just mount the devices to the floor first in the correct positions and then place the PCB over and solder them in. best to have the hole there though or you cant get the board off without desoldering them all at once

if you look at the sigma22 power supply by AMB you can see this. see the holes right at the edge? you can just use a small screwdriver through here for mounting



here they are at the edge too, but this would not have to be the case

[Nikola Krivorov]

I don't know what you guys are talking about but I want one board too
Just joking, I have been waiting for that board for quite some time, even sent an email to Owen when the thread started.

[Greg Stewart]

One stereo set (not sure whether it's one board or two for stereo), maybe two sets for me!

Been waiting (patiently!) for this.

Greg in Mississippi

[qusp]

I think I prefer the right hand side layout. looks to be slightly more compact and with a more logical flow for signal. looks like you have a spdif MUX and simple power supply for the buff on there too. that would be great if I were using it and not the ackodac so yeah as long as its easy for me to use my own power source (ie. easy mounting point for molex after your regs) then i'll be in heaven. if 1 board is stereo balanced, I would want 2, if only a single balanced channel, I would take 4. this is minimum as I may grab some for a friend

[frozen wing]

I would be interested also for those boards Owen

[opc]

Hi Guys,

So there's a little more interest than I had initially guessed, which means I'll get my act together and get this thing finished.

I would like to appeal to the greatest number of people possible, but not detract too much from the layout in the process.

I do indeed have provisions for an adjustable 5V reg for the DAC itself, I have all three standard digital input formats (SPDIF, AES/EBU, Toslink) with a 6 pin header to select the desired one (could be wired to a switch).

The board is designed to drop a TP Buffalo II board directly on top, but if someone who owns the ackodac could carefully measure out the input and output connector locations (as well as the board outline, etc.) then I could possibly design it for both providing it doesn't make a complete mess.

I will also include proper connectors for bypassing any of the on-board power supplies if you feel the desire to tinker with that.

One other thing I'm trying to sort out is where to have the boards made, and how much it will cost to go with 4 layers. I always feel that a greater layer count results in better layouts, so I'd like to know if people would be willing to pay a little more for a 4 layer PCB.

Anyone with suggestions on PCB manufacturers who can do reasonably priced 4 layer boards in smaller quantities, please let me know. Any other suggestions for additions to the board are also welcome.

Cheers,
Owen

[neb001]

Just wanted to post that I'm interested in boards as well

[Nikola Krivorov]

Hi Owen,

A while ago there was a group buy for a phono stage board and the guys used a company that is actually in my hometown, I think they did a good job, have a look at their site:

OLIMEX Ltd. - Electronic Design and PCB sub-contract assembly OEM/ODM service

Not sure if they do 4 layer though...

[opc]

qusp:

One board is indeed balanced stereo output, and I've tried to include everything on board so all that would be needed is a pair of small transformers to make it all functional.

I'll look into your suggestion for under-board mounting of the resistors and transistors, which might actually work for this setup. I'm used to bolting down through the PCB and pinching the transistor between the PCB and the heatsink, but that wouldn't work in this case since both the resistors and the transistors have very different thicknesses. Bolting them down first, and then mounting/soldering the PCB might work well though, and if I place holes at the correct locations, then it might be possible to get everything off without having to de-solder.

I agree with you that the right hand side is the more logical layout, so I'll probably go with that. I'll get rid of the output XLR connector and just come off with a header since having outputs on the side is a little lame. People can wire up their own output connectors, and that leaves more room for output coupling caps.

Looks like we're up to between 15 and 20 boards, so I'll probably put in an order for between 30 or 40 to start. Maybe a group buy for the transformers would be in order as well. I'll look into it.

EUVL:

I'd be shocked if those JFETs had higher transconductance than the FQA32N20's. I measured 0.922 S with 130mA and 25VDS where the Toshiba looks like it'll be around 0.5 S (kudos to Toshiba for actually putting Yfs on the datasheet)

Still, I'll pick up a pair and see how they do. It's always good to try as many different devices as possible.

Cheers,
Owen

[PierreQuiRoule]

Originally Posted by opc

Hi Guys,
Anyone with suggestions on PCB manufacturers who can do reasonably priced 4 layer boards in smaller quantities, please let me know.

Gold Phoenix PCB fabricated my D1 boards. Their prices are reasonable for small quantities up to 8 layers, and shipping to Canada is cheap. IMO their quality is acceptable for such simple analog designs.