Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #120 on: December 20, 2018, 12:01:41 PM »
that's why i do that. i've been using it for so long i know some very cheap and reliable brands.
most film and electrolitic capacitors are now Panasonic and Nichicon, which is nice :)


LCoggan

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #121 on: January 05, 2019, 10:15:23 PM »
So I’ve just skimmed through this thread and the old one and had to create an account so I could join in.

I’ve been struggling for ages to find a cheap way of recording multiple audio channels on to my computer and keep them separate. After finding out how expensive it was going to be I did my usual thing of thinking ‘well surely it can’t be hard to just make one myself’. After a small amount of research I soon realised how complex this subject is and how wrong I was about it not being difficult.

Then I stumbled across this feed and my prayers were answered. I was so close to believing I was the only person ever to have such specific needs and a desire to DIY. 

I’ve had a quick look at the Infinitas boards and I’m not 100% what specifically they allow for. My personal needs are multiple XLR inputs (around 12 at least), and a USB output that I can connect to my PC to record all the channels as separate tracks. Will Infinitas cover this?

I’m very interested in this project (especially considering it saves me doing the R&D myself, not that I wouldn’t enjoy the process, I just have a busy life). Really looking forward to hearing back from you.

Liam.

rkn80

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #122 on: January 06, 2019, 10:28:00 AM »
Liam,

nice that you found this thread!

For your configuration you would need the [Infinitas] core board and two Analog-IO-x8 expansion boards. That will give you 16 channels In and 16 channels out, full-duplex, all balanced.
For XLR you can either use a standard Sub-D-to-XLR cable (Tascam pinout) or connect the XLRs directly to the IDC connector directly behind the SubD on the PCBs.

Raphael

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #123 on: January 06, 2019, 01:05:52 PM »
But keep in mind that those are Line inputs. If you are pluging microphones, you need a microphone preamp between the microphone and the infinitas input

bernatvm

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #124 on: January 07, 2019, 03:44:30 AM »
Do you need any special tools to program the chips or they are programmed already?

LCoggan

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #125 on: January 07, 2019, 12:46:15 PM »
Thanks. Could I use a standard amplifier circuit as a mic preamp with gain control on the output or is it more complex than that? Do you think I’d be better off with an opamp?

rkn80

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #126 on: January 08, 2019, 04:45:36 AM »
Do you need any special tools to program the chips or they are programmed already?

You need am xTAG to program the XMOS-device for 19$ from digikey as stated in the documentation.

If you want to use the DSP option you can either use a USBi ( from Analog or from the freeDSP project) or program the DSP via the XMOS device on the [Infinitas] core board. For the second option you don't need an extra tool once you have the xTAG programmer.

rkn80

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #127 on: January 08, 2019, 04:47:21 AM »
Thanks. Could I use a standard amplifier circuit as a mic preamp with gain control on the output or is it more complex than that? Do you think I’d be better off with an opamp?

The only requirement is to have a +6dBu output balanced at the output of your mic preamp. How you make the mic preamp is then a question of your personal taste.

iampoor1

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #128 on: January 08, 2019, 04:20:43 PM »
Where are you guys sourcing the AK4558 from? Digikey in the USA doesnt have any stock and a 20 week lead time.

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #129 on: January 08, 2019, 05:09:06 PM »
no clue yet...


iampoor1

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #130 on: January 08, 2019, 09:28:30 PM »
Hmmm,Im beginning to wonder if the 4458/2/4/6 is being discontinued. Looks like digikey has ever other 8 channel DAC AKM makes in stock!

rkn80

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #131 on: January 13, 2019, 08:19:20 AM »
Hi,

too bad, digikey is the only source for the AK4458 in very small quantities.
I saw this issue happening with digikey earlier already, sometime they just run out of stock. In December the AK4458 was still available.
According to the AKM website the AK4458 is not EOL. And it is unlikely because they have no 8-channel replacement yet.
According to digikey the AK4458 can be delivered on 2/20/2019. I just put one in my basket and checked delivery time.

Raphael

rkn80

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #132 on: January 13, 2019, 08:21:32 AM »
You need am xTAG to program the XMOS-device for 19$ from digikey as stated in the documentation.

If you want to use the DSP option you can either use a USBi ( from Analog or from the freeDSP project) or program the DSP via the XMOS device on the [Infinitas] core board. For the second option you don't need an extra tool once you have the xTAG programmer.

I am sorry, I forgot to mention that you also need a usb-to-serial adapter like a ft2232-board to program the FPGA. These boards can be ordered for a few $ from many suppliers. Usually makers have such a device in their toolbox.

mhelin

Re: [Infinitas]: USB Audio Class 2 Interface, 32 in, 32 out, DSP
« Reply #133 on: January 13, 2019, 05:38:19 PM »
If the AK4458 is unavailable you can use the 6ch version AK4456 which is available on digikey. Obviously you loose 2 channels then. Check datasheet, you'll need just couple of 0 ohm resistors more.
Mikko


 

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