Small project update and wooden headphones side project

As the Soekrates boards are still stuck in America, I finally caved in and burned roughly $500 to import some DAM1021-2 boards from the Soekris EU distributor. While I wait for them, the transformers and the LT3042-based power supplies to arrive, I'll show you a little something special: another little glimpse of a side project I've been working on.

These are wooden headphones based around a very special headphone driver (which I shall not mention in order to avoid driving up prices). Down below, you can see the basic plans. Wooden cups reinforced with a metal ring around the outside with metal gimbals connected to each other with a single metal wire. Shouldn't weigh too much and it should sound good too.

Progress update

Apologies for not posting much at all.

The project is stalled for now, as I had both my proto boards sent to a friend in the US to save on shipping (as I planned to have him ship many things at once). I had everything planned out until I found out I couldn't pay for the shipping label with my PayPal then it started falling apart from there. In addition to that, he can't send them on with his own money due to very complicated reasons so I pretty much have run out of things to do without touching the boards themself.

That said, I'm thinking about the different engineering challenges and compromises that is involved with the use of one board verses the use of two. Use of a single board means that differential output has to pass through two opamps via a single-ended to balanced buffer and it'll have a noticeable (adverse imo) affect on sound quality due to the opamps. This can be somewhat remedied if I swap the opamps but it adds another element of failure for the manufacturing process and then we'll have a whole new debate over which opamps different people want. This can be somewhat fixed if I stick a socket there but it will add noise and then I might as well not change the opamps.

However, having two boards adds its own challenges too. I have to parallel each of the digital inputs and supply power supplies to each board (I'm not sure what effect paralleling the same supply will have as per the latest plan I have), connect the serial lines to each other and increase the height of the enclosure significantly to take the two boards. This is without taking into account any other mods I may or may not perform for sound quality (as detailed on the blog) as twice the number of boards means twice the failure rate.

The reason why I'm troubling over this is because I would much prefer to offer either SE or differential options only as offering both would mean having to increase the price across the board due to smaller production runs meaning more expensive per-unit costs. Overall, I still haven't decided on whether to use dual or single boards (especially because an extra board also increases the price by a large chunk).

Soekrates detailed labelling

Back to single small chassis for the Soekrates

I'm excited! I found this thing while browsing the web the other day.

It's called 'The Wire LT3042 Parallel Reg PSU' and is, fittingly, a LT3042-based power supply with two rails per board. The thing is, it's sized at 74mm x 26mm for a DUAL RAIL! That means I need only two for the Soekrates if I parallel the bipolar supply into each DAM board and this allows me to use only one transformer and therefore shrink the size of the Soekrates to a very manageable size.

DAC updates (this is revision 11!!)

I've just realized that the number of times I've updated the DAC design so far is quite daunting. I've again reverted it to the dual chassis design due to not liking the large form factor of the single chassis design.

Backplane board for the Soekrates

I've decided to design my own backplane board for the Soekrates. Here's the circuit diagram that I intend to use (which might change at any time):

The J1, J2 and J3 headers follow this format, and there are two of them because of the dual DAM1021 balanced setup:

WaveIO cost updates

Lucian and I have been exchanging emails and we've managed to work something out:

  From what I understand so far, you need only the isolated I2S port thus
the parts from SPDIF and non-isolated outputs will be removed. Given
this, the price for one board became 94.6 Euro.

  As for discounts, first I would like to tell you that, in order to have
an affordable price for this board while offering the best audio quality
at the moment of designing (which is reflected in good layout and best
components for this board) I'm acquiring parts for quantities of 250
WaveIOs at a time. Anyway, there are some margins that can be bend so we
all can have financial benefits and here they are:

  For orders of 20+ boards: the discount is 3% per board. This means that
for an order of 20 boards, you'll pay 91.762 Euro per board.
  For orders of 50+ boards: the discount is 6% per board. In this case,
for an order of 50 pcs. the price for one board becomes 88.924 Euro.

  In case of 100+ orders: the discount is 9% per board. Here one board
have a price of 86.086 Euro.

  I hope my mathematics are okay at this hour :-)
  Anyway, to put it simple, on orders of 50+ you'll pay for maximum 47
WaveIOs and get minimum three WaveIOs for free. At orders starting with
100 pcs. you'll pay for maximum 91 boards while get minimum 9 for free.

  In addition, for ALL orders over 20 pcs. you have the chance to have
your own customized drivers meaning that you can change the "WaveIO"
name on Windows installation and firmware and put the name of your DAC
there, for example! In addition, the image used at instalation process
can be changed with your own one: changed from Luckit/WaveIO to the name
of your DAC.

It would be awesome to sell 20 of the Soekrates DACs and have it be called Soekrates when it's recognized by the computer!