ask

Re: Modular multi channel DIY AD/DA Box
« Reply #60 on: October 06, 2009, 06:04:30 PM »
very nice! ::)


Well, I tested the 4 channels you can see populated on the picture. They are working so far. Today evening I tuned some filter componentes for a good frequency response. Btw. the DACs give now a maximum output voltage swing of ~21dBu (adjustable via resistor selection).

I see that there are different thoughts about the digital inputs. All of the mentioned the formats are possible as soon as a board is designed for it. Again I'll first go for ADAT (48kHz and 96kHz SMUX) so if someone is willing to design an AES/SPDIF board you're welcome.

Raphael
Happiness is a warm soldering gun.


rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #61 on: October 08, 2009, 05:41:48 AM »
Yesterday evening I tried to measure the THD+N. Too bad, with my Presouns Firebox I'm not able to measure it, the THD+N of the Firebox is already too high (or the THD+N of the PCM4104-board is too low... ;) ). Any ideas how to measure it wihout very expensive tools?
When the AD-pcb is there I can measure it for the combination of my AD/DA board because then I can go into it and out of it digital via S/P-DIF.

Raphael

Re: Modular multi channel DIY AD/DA Box
« Reply #62 on: October 08, 2009, 06:21:28 AM »
This looks amazing but miniaturized SMD for all the analog components? A version with through-holes would allow all the great parts we know and easier work flow for most of us.

I'd just be overjoyed at through-hole PCBs.

If the circuit works, maybe someone can print another PCB layout of the same circuit with through-hole for those of us who want it?

Also, in terms of features, I'd like line in ADC and would vote for higher spec adc/dac chips as well if possible. A word clock in BNC sync will also be good.

But mostly I want through hole components.  ;D

Moby

Re: Modular multi channel DIY AD/DA Box
« Reply #63 on: October 08, 2009, 06:42:48 AM »
Great Raphael. I notice your thread today and it looks promising. I don't see any problem with DIY SMD if U use magnifier glass and good soldering tip  ;D BTW, AES/EBU board will be great . Just stay sharp mate 8)
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #64 on: October 08, 2009, 07:59:53 AM »
This looks amazing but miniaturized SMD for all the analog components? A version with through-holes would allow all the great parts we know and easier work flow for most of us.

... and would vote for higher spec adc/dac chips as well if possible ...

To be honest I wanted to keep the project at a good cost/performance ration in the first step. Of course you can use a AD1955 or a PCM179x but these chips are much more expensive for just 3dB additional SNR or whatever. So I decided because I need for myself 24channels to use the PCM4104 for now. Same thoughts on the ADC. Two PCM4204 are cheaper then a CS5368 or some PCM4220s.
Besides that SMDs are good for the performance they're cost reducing. Interestingly the SMD components from my distributors are cheaper then the equivalent through-holes and SMDs are space saving on the pcb. That reduces pcb production costs. :D

If the circuit works, maybe someone can print another PCB layout of the same circuit with through-hole for those of us who want it?
If so I'd be pleased to provide the volunteer with the design files. if helpful.

Raphael

bernbrue

Re: Modular multi channel DIY AD/DA Box
« Reply #65 on: October 08, 2009, 09:02:28 AM »
Hi Raphael,
very interesting project. Great work! I really admire the "straight forward" way you introduced your project here in prod pro.
@all: may I suggest to let Raphael finish his project the way he wants to do it. The converter board seems to be very versatile and open for quite a lot of options to be implemented. Concerning SMD Raphael gave a lot of hints how to solder these parts. I never worked with SMD but I´m willing to learn and to try. I agree with Raphael to aim for a good cost/performance ratio, otherwise it wouldn´t make sense to DIY a ADC/DAC.
 
Go on, Raphael

regards
Bernd

Re: Modular multi channel DIY AD/DA Box
« Reply #66 on: October 08, 2009, 05:32:54 PM »

To be honest I wanted to keep the project at a good cost/performance ration in the first step. Of course you can use a AD1955 or a PCM179x but these chips are much more expensive for just 3dB additional SNR or whatever. So I decided because I need for myself 24channels to use the PCM4104 for now. Same thoughts on the ADC. Two PCM4204 are cheaper then a CS5368 or some PCM4220s.
Besides that SMDs are good for the performance they're cost reducing. Interestingly the SMD components from my distributors are cheaper then the equivalent through-holes and SMDs are space saving on the pcb. That reduces pcb production costs. :D

If the circuit works, maybe someone can print another PCB layout of the same circuit with through-hole for those of us who want it?
If so I'd be pleased to provide the volunteer with the design files. if helpful.

Raphael

That sounds great Raphael. I understand about your converter chips - they still spec very well and should be quite affordable. As for SMD vs through-hole, I've been looking around and SMD should actually be okay. I'm warming to it.

Personally, I could use 32-48 d/a + 16 a/d, so this project is very much of interest to me and I'm sure a lot of others here as well. Thanks for all your hard work so far. :)
« Last Edit: October 09, 2009, 09:16:41 PM by audiovisceral »

radiance

Re: Modular multi channel DIY AD/DA Box
« Reply #67 on: October 08, 2009, 05:58:41 PM »
Yesterday evening I tried to measure the THD+N. Too bad, with my Presouns Firebox I'm not able to measure it, the THD+N of the Firebox is already too high (or the THD+N of the PCM4104-board is too low... ;) ). Any ideas how to measure it wihout very expensive tools?
When the AD-pcb is there I can measure it for the combination of my AD/DA board because then I can go into it and out of it digital via S/P-DIF.

Raphael

Just boost the signal somewhere along the line...or in you DAW ...
« Last Edit: October 08, 2009, 07:02:40 PM by radiance »
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

skipwave

Re: Modular multi channel DIY AD/DA Box
« Reply #68 on: October 09, 2009, 12:41:50 AM »
It is and it is much easier then it looks and faster then wired parts. :)

It is very DIY-able. Just get a nice little clip and posable holder thing-y. Magnifying glass also helps. Then just tin, stick, repeat.  ;D

Very interested to see this project continue to develop.
Quote from: PRR
Now, maybe you don't, or shouldn't, grab the ribbon for far-harpsichord, nor the hot condenser for snare-kissing... yet often we do.

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #69 on: October 12, 2009, 02:23:14 AM »
Here is a link which explains how to solder SMD ICs with standard tools. It is in German but I think the pictures and the youtube clip are self-explaining:

http://thomaspfeifer.net/smd_loeten_tsop.htm

Raphael




mainmachine

Re: Modular multi channel DIY AD/DA Box
« Reply #71 on: October 13, 2009, 03:32:48 PM »
After watching that, I am ordering some liquid and paste flux, and I would like to express my interest in this project.

rkn80- count me in on the group buy! I'd like to try 8 channels of these converters, but I'll go in for up to 32 if it'll bring the costs down per board. How many people are in on this? What are the price breaks on ordering these boards?


Also a tonne of help here:
http://www.curiousinventor.com/guides/Surface_Mount_Soldering


Engineer's Motto: If it isn't broken, take it apart and fix it

Biasrocks

Re: Modular multi channel DIY AD/DA Box
« Reply #72 on: October 13, 2009, 03:57:19 PM »
The surface mount stuff still kind of scares my 47 year old hands...

But, I'd be down for 16 channels of D-A with an ADAT SMUX Interface.

Nothing like jumping in with both feet. :)

Mark
« Last Edit: October 13, 2009, 05:06:21 PM by Biasrocks »
http://SharktankPro.com

"I'd rather use an SPX90 than a UA plugin....." Joe Barresi

syn

Re: Modular multi channel DIY AD/DA Box
« Reply #73 on: October 13, 2009, 04:18:36 PM »
 :o
I'm in.
Any idea of the prices?

baadc0de

Re: Modular multi channel DIY AD/DA Box
« Reply #74 on: October 13, 2009, 04:46:31 PM »
This sounds cool. I'd love to give it a bash with 24 in, 24 out.

mainmachine

Re: Modular multi channel DIY AD/DA Box
« Reply #75 on: October 13, 2009, 07:59:48 PM »
If the performance of these converters warrants, a group buy for SOIC-8 dual opamps, PCM4104, PCM4204 and all the other components would be in order. Prices get pretty nice at 100+ parts, and due to the repetitive nature of this project (lots of parallel, identical channels) the numbers add up fast.

16 channels x 4 dual opamps = 64 peices, so if 8 people are building 16 ch. units we're at 500 piece pricing for the opamps, 100 piece price for the A/D and D/A chips- these could be very inexpensive!

I'd be leaning towards BB OPA2604 opamps- any input?

I'm probably getting ahead of the project here, but I'm psyched at the prospect of lots of channels of good sounding A/D/A conversion!

-Dave
Engineer's Motto: If it isn't broken, take it apart and fix it

Rochey

Re: Modular multi channel DIY AD/DA Box
« Reply #76 on: October 13, 2009, 08:03:55 PM »
I've been watching this too.  ;)

OPA1612 is the way to go.
Expat Audio Home: http://www.expataudio.com

Re: Modular multi channel DIY AD/DA Box
« Reply #77 on: October 13, 2009, 08:20:23 PM »
Personally not a big fan of the Burr Browns. I'd prefer Analog Devices opamps like what Raphael mentioned. AD8620, AD8599, AD823, etc.

But I doubt we'd ever all agree on opamps.

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #78 on: October 14, 2009, 07:11:14 AM »
I agree. We will never find an opamp that we all like! :)

The status of the project is at this moment that most of parts are now mounted on my 24channel prototype DAC pcb. Some resistors and capacitors still to go. Unfortunately I've damaged my solder iron when I wanted to change the tip of it yesterday (the tip is fixed with a srew and this screw is broken :( ). Today I'll buy a new one and hopefully today evening all 24channels will be done.

Regarding a group buy:

I would be happy to organize that. The last price for one 4channel board was ~25Eur if I buy 10 of it (that's why I decided to put 6 boards on one pcb, total cost reduced...). 10 boards is the minimum. If  we have more orders then th eprice will go down. I'm a little bit unsure how to proceed with the group buy. Perhaps I should open a seperate thread in the black market section. That will keep away the ordering things from the technical discussion here. What do you think?

Raphael


 

bernbrue

Re: Modular multi channel DIY AD/DA Box
« Reply #79 on: October 14, 2009, 09:29:08 AM »
Hi Raphael,
open up a new thread (feeler) in BM, that would keep the business out of this thread. I very much appreciate that you want to organize a groupbuy for the components, since you already sourced the parts for your prototype and know where to get the necessary parts. Pcbs and parts in one hand seem to be the best solution. Would it make sense to put together a kit? So everyone can decide, if he wants to buy the pcbs only, pcbs plus parts, maybe a kit with presoldered DAC. I don´t know. Anyway, take your time with prototyping. Personally I think it´s too early to think of  groupbuys and commercial stuff in general. I would also appreciate that your immense efforts to bring this project so far and your decision to share it with us is going to be honored with some extra money, when selling pcbs and parts.
regards
Bernd


 

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