[promixe]

On the preamp board:
Do I live J3 and J4 open?

J4 leave open for sure. J3 - I couldn't measure a significant difference in having that one open or soldered. This is the jumper that stitches together AGND and DGND at the power supply header. AGND and DGND connect at the THATDIP adapter anyway, so J3 is there to experiment. =) I'd leave it open to start with.

The "PROG" jumper on both the UMPC MIDI and Front Panel boards is for programming the chips in-circuit and since you're using the UMPC firmware already you should short them for stability. Not between the boards but individually on each board. That way the RESET pin of uC connects to VDD.

You should use thermal insulating material between the regs and heatsinks, as well as plastic washers on both sides of the screw that fastens the regs to the heatsink. I will dig up links of the products I use for this task and post them here ASAP. There are kits for TO-220 insulation that Mouser carries.

http://www.mouser.com/ProductDetail/Aavid-Thermalloy/56-77-11G/?qs=AUZKTHQUMUBi5NtSpsq66v%2fzF8xDcgOYuYs06Spcc8Q%3d
http://www.futureelectronics.com/en/Search.aspx?dsNav=Ntk:PartNumberSearch%7c7721%2f-7PPSG%7c1%7c,Ny:True,Nea:True
These worked for me!

[i3j0rn]

MAny thanks!

By the way... There are no cable housings in the Bom so...
Some suggestions...
Housings matching the 2X5P headers connectors:
http://fr.mouser.com/Search/ProductDetail.aspx?R=66900-110LFvirtualkey64910000virtualkey649-66900-110LF
http://fr.mouser.com/Search/ProductDetail.aspx?R=71600-010LFvirtualkey64910000virtualkey649-71600-010LF
 
Ribbon cable:
http://fr.mouser.com/Search/ProductDetail.aspx?R=191-2801-110FTvirtualkey52320000virtualkey523-191-2801-110FT

I used these and it worked fine.
It can maybe help future builders (beginners like me)...

[i3j0rn]

Hi. Final steps. I have spent some time drawing the front panel... It's almost done.

I'm ready for a test !
I have a dual 25V 40VA toroïd transformer.
It is wired like this:

Red 25V
Black 0V
Yellow 25V
Orange 0V

If I understand...
Black and yellow goes to PSU CT and Red and Orange to AC... Am I right?

I've mounted micas film and plastic washers on the ICs. How can I be sure they are insulated well?

[promixe]

Black should go to "AC." (with the phase dot)
Yellow to "AC" (no dot)
Red + Orange should go to "CT" (center tap).
Make sure you ground your circuit - there is a "CHA" connection at the PSU, this should connect to Earth terminal on your IEC power entry module. Double check everything, you don't want to start a fire with wiring this incorrectly!

You should test the heatsinks and regulator tabs with a DMM in continuity mode. Make sure the film you used to insulate the tabs from heatsinks transfers heat well because otherwise the heatsinks become useless and regs have a high probability of burning out.

Test the PSU without load first. Then when you make sure the voltages are right connect it to the preamps and controllers.

[i3j0rn]

Ok. Good news I powered it up and no one Is dead. 

[promixe]

Ok. Good news I powered it up and no one Is dead. 

This is GREAT to hear! =) Give us pictures! =)

[i3j0rn]

Update..
IT WORKS!! 

First test:
Plugged a RE20... Turned on my guitar amplifier.
Wow. It's great!
It's quiet, super clean, really detailled, precise and soft in the same time.
It really is a superb tool.

The midi remote is working fine!

Tomorow: Recording!

Thank you so much for everything.

Ps: I promise to send pictures when I receive my front panel. I putted it on a spare rack I had. It's functionnal but I want it to look as good as it sound. 
Do you want some audio samples?

[promixe]

Very cool! Put anything you have up here (or on your page if you have one and post a link here): audio, pictures, impressions, mics you use with it, etc.

"Precise and soft at the same time" - this is actually a very good description of how I feel about the preamps most of the time! I call it "musical" - no harshness, but no detail is lost. =)

Thanks for undertaking this project! =)

[i3j0rn]

Audio test
http://soundcloud.com/jonat/innersonix-lucidity-preamp-1

ELECTROVOICE RE20
INNERSONIX Lucidity preamplifier
RME Fireface

I also tried it on drums. The midi remote changed my life. I can try mic placement and adjust my gains without moving from behind the drumkit.   
I'm very pleased and I can really recommand those preamps!

[ArnauTS]

Sounds good! reminds me the sound of millenia preamp.
Thanks for the sample

Audio test
http://soundcloud.com/jonat/innersonix-lucidity-preamp-1

ELECTROVOICE RE20
INNERSONIX Lucidity preamplifier
RME Fireface

I also tried it on drums. The midi remote changed my life. I can try mic placement and adjust my gains without moving from behind the drumkit.   
I'm very pleased and I can really recommand those preamps!

[promixe]

There hasn't been much activity with this project in a while. I still have over 30 channels of Lucidity Preamp PCBs left - anyone willing to try them out? =) It seems that super-clean and precise modern preamps are not that popular around GroupDIY for some reason. Either most people don't dig hybrid analog/digital circuits as much as the old discrete analog-only ones, or it's something else. It is certainly not the cost or ease of build - anyone wants to chime in as to what would be the reason for this design to remain unpopular? =)

I started developing a remote control app to support up to 256 channels of Lucidity over Ethernet or WiFi with presets, metering, auto gain, etc., but am not confident at the moment if time spent developing it will pay off in any way, judging by the current activity of the project. It would more or less be a month or two of full-time commitment to get this going and at this point in my life I can't say I could do it just for kicks. =)

I'm very thankful for a handful of early adopters, I hope you are enjoying the sonic fidelity of Lucidity preamps! Please tell about and SHOW this design to your friends and colleagues, maybe they will get on board as well! =)

Thank you!

________________________
www.facebook.com/innersonix

[bremusound]

Do you still offer discounts for group members or when ordering 8+ of the PCBs and THATDIP adapters?
I'm still interested but probably have to get rid of some gear first...

[promixe]

Do you still offer discounts for group members or when ordering 8+ of the PCBs and THATDIP adapters?
I'm still interested but probably have to get rid of some gear first...

Yes, the coupons should still work. If anyone runs into a problem ordering through the website please drop me a PM and I will assist right away. Thanks!

Here are the coupon codes (apply them at checkout):

• FREEPSUV1 - When purchasing 8 or more channels of Lucidity PCBs get the PSU v1 for free (needs to be in the cart for coupon to work).
• GROUPDIY8CH - 25% discount on Lucidity PCBs when ordering 8 or more with THATDIP adapters

[plinker]

I am interested in this project.

How  much total gain out of the preamp?

Also, what cases do you recommend?

Thanks,
Jim

[promixe]

How  much total gain out of the preamp?

It's customizable at the output line driver, but I've tested them with 70 and 75dB total gain (+68.6 from 1570+5171 chips and +6.4 at LME49860 driver). The firmware supports up to +80dB displayed gain. Regardless of the line driver gain the overall output of the preamp is limited by the voltage rails, which at +/-17V (the limit of THAT5171) outputs around +28.5dBu before starting to clip (this is from memory, can't verify at the moment).

Also, what cases do you recommend?

I use ModuShop cases - they are not the cheapest around, but very high quality! They ship from Italy.

[mrcase]

hey!

where can I find the bom for the PSU and the frontpanelcontrol? I could only find the bom for the preamp on your site.
And where can I find the cutout info for the Frontpanel controller?

cheers

[plinker]

Same questions as MrCase.

Thanks.

[mrcase]

I found the Boms, if those are the actual ones. Still missing the cutout info though...
http://www.groupdiy.com/index.php?topic=45035.msg607977#msg607977

[soundofseba]

Hi,

Is one UPS enough to power eight preamps? I guess the UPS needs some modification to work with European 220V?

[plinker]

You mean "PSU", right??

Hi,

Is one UPS enough to power eight preamps? I guess the UPS needs some modification to work with European 220V?

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