promixe

For 2012-13 updates on this project please visit my site!

For build/support thread on GroupDIY click HERE

For a mini-diary of the R&D process click HERE



Hi All,

I just finished doing preliminary testing on my THATDIP Lucidity Preamp PCB and it seems to work great. Next step is to plug a mic in and LISTEN. =)

UPDATE: Just plugged a mic in and tested the preamp on vocals - wow... I'm actually very impressed, after having worked with Prism, Grace, Lavry stuff, this sounds damn clean, yet not "sterile" i.e. unmusical - paired to a cheap dynamic mic (Audix OM-3xb is what I immediately had access to, serious condenser testing is ahead =)



The board features my THATDIP adapter that utilizes THAT1570 & THAT5171 digitally controlled preamp chipset. The board also features flexible output stage making it possible to do either balanced or single-ended out. The PCBs are very tiny - 147x36mm (1.4"x5.8") so it's easy to fit 8 of them in 1RU.



I will be preparing documentation to get people started with this project. Up to 8 channels can be controlled via a single front panel controller. I have a few pilot-run PCBs for both the preamp and the controller if someone is interested.

I'm also working on a MIDI controller board for the project to emulate Digidesign PRE if hooked up into Pro Tools. Also I may be making a digitally controlled minimal compressor to be inserted past the preamps - ideal for mobile recording workflow.

Is there any interest in the project? =)
« Last Edit: January 01, 2013, 09:34:00 PM by promixe »


Ptownkid

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS]
« Reply #1 on: July 16, 2011, 12:30:10 PM »
Radness!!!

spreemusik

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS]
« Reply #2 on: July 16, 2011, 02:29:54 PM »
How far can the controller and the preamps be apart?

promixe

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS] New
« Reply #3 on: July 16, 2011, 02:40:20 PM »
How far can the controller and the preamps be apart?

I haven't tested max length yet, but the SPI bus works at 8Mhz = 125ns clock cycle. Generically speaking it's 1 ft per 1ns...
Having said that, this particular controller was designed for FRONT PANEL control and assumed it will be in the same chassis with preamp boards. If you need a REMOTE controller it is better to use something like RS-485 over twisted pair or similar. Then we're talking 100+ ft easily done. I'm going to investigate if I can do a simple SPI to RS-485 board for this project specifically for remote use.
« Last Edit: January 01, 2013, 09:35:23 PM by promixe »

Peterson Goodwyn

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS]
« Reply #4 on: July 16, 2011, 04:00:12 PM »
Whoah! Awesome. I am just finishing up an 8-channel rack of MCS' 1512-based boards and I was likewise impressed by their musicality. Might embark on a rack of these next...

spreemusik

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS]
« Reply #5 on: July 17, 2011, 04:52:25 AM »
If you need a REMOTE controller it is better to use something like RS-485 over twisted pair or similar. Then we're talking 100+ ft easily done. I'm going to investigate if I can do a simple SPI to RS-485 board for this project specifically for remote use.
Yes, I really need a remote controller, and a rack of 8 pres in the piano room. That's about 20m (65ft?) of cable, so MIDI won't cut it. RS-485 sounds good.  I suppose, given a bit of time, I could devise my own controller.

nielsk

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS]
« Reply #6 on: July 17, 2011, 08:22:02 AM »
If it could use the same protocol as the Aphex 1788RC then one could use the Aphex remote (a great unit and not very expensive) and go 1,000 feet over CAT5 or +1kM over fiber w/ converters.
One could also use the free software to control using a PC...http://www.aphex.com/1788A_downloads.htm
As the system started using MIDI, I suspect the data protocol is based on the same format, & the basic configuration is 8x8 (8 banks of 8 channel units)
« Last Edit: July 17, 2011, 08:25:26 AM by nielsk »

promixe

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS] New
« Reply #7 on: July 17, 2011, 11:34:30 AM »
If it could use the same protocol as the Aphex 1788RC

I initially thought of using Digidesign PRE OR Aphex 1788 MIDI format, switchable. It would basically emulate either unit MIDI message wise, receive their commands, translate to SPI, my front panel controller would grab it and talk to the actual preamps. If front panel settings are modified, send SPI to MIDI board, the MIDI board translates to either Aphex or PRE MIDI message and sends it out... Kind of like that.

But the initial idea was to control these preamps via Ethernet with anything that has a HTML5 compatible browser (i.e. iPad, laptop, etc.)



You would basically connect the preamp to your LAN, it would use Bonjour to set up itself and find other units and have unified interface (kind of like above) for, say, 64 channels of clean goodness. =)
« Last Edit: January 01, 2013, 09:40:15 PM by promixe »

promixe

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Pre [PICS] New
« Reply #8 on: July 17, 2011, 02:49:19 PM »
Aphex remote (a great unit and not very expensive)

It is a good unit, BUT $1299 seems a bit steep for me personally, compared to the DIY nature of the project it would control... Then its protocol would need to be reverse-engineered, which assumes I'd have to obtain a unit somehow. =) Therefore I am interested in making my own version of DIY RCU for these preamps, then it would be a sub-$300-400 remote, much more affordable, with similar features, and a lot of time would be saved by just implementing my own protocol to suit what I have already coded for the front panel controller (picture below).



I don't know availability of which additional PCB (MIDI, Remote, PSU, Metering, Compressor) would make this project more desirable for people to undertake. Also, there is a lot to think about in terms of how to interconnect everything (the logical part of it, i.e. what is master/slave at what level, etc.).

=)
« Last Edit: January 01, 2013, 09:42:34 PM by promixe »

radardoug

Very cool project! One thing to bear in mind, you can convert MIDI to RS485 very easily, you just have to put the signal through an RS485 interface chip at each end. Tie the chips so they only transmit or receive as appropriate at each end. It all runs off 5 volts which you could steal at each end.


Joelv

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #10 on: July 17, 2011, 10:05:11 PM »
Awesome! I'm interested in 8 units for sure, possibly more. Any idea on when these will be available?

12volts

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #11 on: July 19, 2011, 03:45:11 PM »
I'm thrilled with this design/implementation. I'll have 8 boards (PGA2500) and a controller when they are available, just for starters.
Have  an ethernet controller and I'll cream my pants! Please keep us up to date with developments.

Frank B.

Matador

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #12 on: July 19, 2011, 05:40:55 PM »
What about using a Microchip ENC28J60?  There's a lot of very simple PIC based web servers (a few in the sub $25 range) that include SPI:  each of your boards could run a simple web server where you could make adjustments just using the standard HTTP protocol.

12volts

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #13 on: July 19, 2011, 06:25:59 PM »
Hmmm, The PIC range is .... unreliable, the claims made in documentation don't necessarily
apply to the device .  Anything in the ATMEL range???

Frank B,

desun

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #14 on: July 20, 2011, 02:45:25 PM »
Yes, interested in this, 8ch in a 1U case would be great project to do! Would be nice to have a play around with the control for these too and come up with a neat front panel design.

fazer

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #15 on: August 03, 2011, 12:22:19 PM »
Very nice fit for me as well.   I have Protools and a command 8 with control for PRE 8ch.   I'm following this with great interest.    Makes a nice remote setup.

Great Job Promixe!

delphi

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #16 on: August 08, 2011, 10:49:31 PM »
Count me in as an early participant to put together a 1U 8 channel version. Excellent work!
All generalizations are false

GnS

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #17 on: August 23, 2011, 12:51:02 PM »
I would be in as well. Gaining and Pad On/off and P48 and Phase over MIDI would be awesome!

Amit

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #18 on: August 25, 2011, 02:26:09 AM »
Nice work!
I'm in for two units, possibly four.
All the best!
/Ami

Moby

Re: THATDIP Preamp - THAT1570/5171 Digitally Controlled Mic Pre [PICS]
« Reply #19 on: December 09, 2011, 12:09:12 PM »
Any news? I would like to build dual unit :)
For microphone transformers,  BV.8,  Bv.11,  Bv.12, etc.. contact me at mobyelectronics at gmail dot com


 

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