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Interest for GB for MarcelvdG valve DAC

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leadbelly

leadbelly

Disabled Account
Joined 2002
#1
[special=]%[/special]This thread is to gauge interest in PCB's and/or major parts for MarcelvdG's valve DAC as published in Linear Audio 13.

Discussion thread here:
Valve DAC from Linear Audio volume 13

Article for purchase here:
Linear Audio | your tech audio resource

Design package download here:
Downloads | Linear Audio

Pictures here:
http://www.diyaudio.com/forums/digital-line-level/166807-dac-gallery-12.html#post5065812

Note that this is a relatively expensive project, the Jensen signal transformer is $USD137 for 1 piece, and the FPGA board is $EUR225 for 1 piece, let alone all other components, so please consider that before expressing interest.

At this point, just please cut and paste the following text into your post and add your name and quantities desired:

Member PCB set Transformer FPGA
leadbelly 1 1 1
 
#5
OK, I received some information back, so we can clarify what costs are looking like.

I received what I think is a good PCB quote from 1 of 2 manufacturers that I submitted to. It looks like the as-delivered cost to me for a PCB set (main & filter boards) is $USD45 based on 15 pieces.

The main board is 2.0 mm FR4, 4 layer of 1 oz copper, 264 * 329 mm, immersion gold surface finish, green solder mask top & bottom, white silk screen top & bottom.

The filter board is 1.6 mm FR4, 1 layer of 1 oz copper, 294 * 160 mm, HASL surface finish.

Budgeting a generous $USD15 for all other costs, assume a total $USD60 cost if we can get 15 to join.

As for the FPGA board, since the price break for 10 units is merely 10% for 10 units, I am thinking it is not worth including in the group buy. Remember there are negatives with a group buy such as costs of shipping twice, risk of loss or damage by shipping twice, and inconvenient manufacturer warranty claim. This decision can await final group buy numbers.

I contacted Cinemag, and they do not have a close, stock substitute for the Jensen, it would have to be a custom. I would think that a custom would not be a big savings, if any, from the Jensen unit. The Jensen unit does discount 15% in price for 12 units, but since it is only used for 1 of 3 build options for the filter board, I would not be surprised if we never get to 12 units.
 
#8
leadbelly said:
The Jensen unit does discount 15% in price for 12 units, but since it is only used for 1 of 3 build options for the filter board, I would not be surprised if we never get to 12 units.
Click to expand...

When you choose the option with signal transformers, you need two of them per DAC (one left and one right), so it boils down to six people wanting to build the most expensive variant. Nonetheless I also wouldn't be surprised if we never get there.
 
#10
This is a really nice project, very interesting I find.

The main PCB (210mm * 297mm) with 4 layers, 70um (2mm) thick and inner layers at 17um can be obtained at FirstPCB. For Qty 5 it cost 160$ USD and with gold immersion 190$ USD for 5 pcs.

I used FirstPCB many times and they do superb PCBs. Don't know if the specs you're looking for though.

Thanks
Do
 
#11
Hi leadbelly,

Do you have any specs you can publish on this thread? I do not want to buy documents yet. Have you auditioned this DAC, if not, can you point to some reviews?

Here's some info that you be nice to have:

- DAC max bit depth and sampling frequency
- Input interface (i2s, coax, toslink, usb, etc...)
- Audio stream supported (PCM, DSD, DoP)
- The usual analog out specs
- Where can we purchase the FPGA board?

Thanks for your help
Do

PS, forget about my previous post, seems like you got everything under control for PCB manufacturing. I had skipped this part while reading too fast...
 
#15
pinnocchio said:
Do you have any specs you can publish on this thread? I do not want to buy documents yet. Have you auditioned this DAC, if not, can you point to some reviews?

Here's some info that you be nice to have:

- DAC max bit depth and sampling frequency
- Input interface (i2s, coax, toslink, usb, etc...)
- Audio stream supported (PCM, DSD, DoP)
- The usual analog out specs
- Where can we purchase the FPGA board?

Thanks for your help
Do
Click to expand...

Hi Do,

So far there is only one of these DACs on the planet, right here in my living room, so there are no reviews yet. For what it's worth, I definitely like it. I've answered your technical questions in the technical discussion thread:

http://www.diyaudio.com/forums/digi...c-linear-audio-volume-13-a-4.html#post5232194

Best regards,
Marcel
 
#17
I really don't need another project, but what the hell lol

Member PCB set Transformer FPGA
leadbelly 1 1 1
Bvtrinh 1 0 1
32y0 1 0 0
pluplog 1 0 1
randytsuch 1 0 0

BTW, digikey carries the fpga board for $214 but none in stock with a pretty long lead time. They must order from trenz whenever someone buys one, and then trenz would need to build and ship over to dk.
 
#18
randytsuch said:
BTW, digikey carries the fpga board for $214 but none in stock with a pretty long lead time. They must order from trenz whenever someone buys one, and then trenz would need to build and ship over to dk.
Click to expand...

Thanks for pointing that out. That is quite significant for North America. The price on the Trenz website is either $USD262 or $USD220 depending on what tax is included and where you are. However, if I order to Canada from digikey.ca I can get it for $CAD305 to my door all in, which is a huge savings. That pretty much kills adding the FPGA as part of the group buy.
 
#20
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