Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #40 on: July 18, 2009, 10:48:04 PM »
OK :)
48V has next logic: it sets the gain to lowest possible, than 48V relay goes on, than gain returned back
to its value. Just kinda speaker protection.

@iban: please see schematic, there should be piece of shielded balanced wire between OUT1 and OUT Molex connectors
and jumpers installed on INS connector, connect: 7and8 , 9and10.
It seems like your pre is working fine (if "clip" lits on on high levels, PGA2500 is alive and well), just missing the jumpers or wire to output XLR.

@SaMpLeGoD: please check polarity of LED's in pushbuttons, worst case you can't fix it, pm me and we'll find a way
to do it.
« Last Edit: July 18, 2009, 10:50:00 PM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)


SaMpLeGoD

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #41 on: July 21, 2009, 05:48:56 PM »
Hello Igor,

Sorry didn't reply earlier, but I'm trying to check out the soldering of the PGA2500... after that I'll post some results... althrough the pushbuttons don't do the right thing, all the rest seems to be well connected...
I think there is some problems wth the PGA soldering :S
I'm just waiting for a frind of mine that is helping me with this...
I'll PM you anyways...

Cheers,

Eddie
Keep on Rockin' and DIYing!!!!

iban

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #42 on: July 22, 2009, 12:47:50 PM »
Thanks Igor! My problem was the balanced wire between OUT1 and OUT Molex connectors, I didn´t see it in the schematic.  :$

Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #43 on: August 10, 2009, 08:54:41 PM »
HUH! Great! Tell me how do you like the sound.
http://www.ij-audio.com
(new site hopefully will be up in July)

kibadachi

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #44 on: August 16, 2009, 03:09:10 AM »
Hi ,


Just wanted to share my experience with the PGA2500 kit.

The sound is crystal clear, dynamic and natural sounding.
I tested this with an AKG 414 BTL II and a Neumann M149. I compared the sound to my Groove Tubes P1, UA LA-610 and a Focusrite ISA 430.
The PGA2500 reveals details i do not hear in my other preamps without sounding EQ'd.  There is not more i can say about it then that you have to try it for yourself.
Now i will go back to finish the final power supply because i was so impatient to hear the sound that i just veroboard'ed a psu to test. I have to start looking into a case because a beast like this deserves a good home ( any recommendations?). When i am done with my recording booth i will put on some samples for reference and comparison.

Compliments to Igor for bringing this quality in design and sound to the DIY community!


Thanks !

Jeffrey


Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #45 on: August 16, 2009, 08:46:05 PM »
Huh. Finally :) I thought this is abndoned thread.
Thanx Jeffrey!
Regarding the case, I very like Shaeffner's cases. But have to check if this fit front pannel.
Purusha BTW can do really cool cases with silkscreening, holes, etc.
http://www.ij-audio.com
(new site hopefully will be up in July)

iban

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #46 on: August 18, 2009, 03:05:42 PM »
I´m sorry Igor for no reply before about the sound of the pres. I have not time to test them. First I´m trying to put them in a case. I´ll write some words as soon as I can :)

SaMpLeGoD

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #47 on: August 18, 2009, 06:56:30 PM »
Hey Igor, I still have no news from my friend, I'm afraid he couldn't solder the PGA2500 propertly, If he don't I'll PM you begging for help... lool

Thanks a lot for your excelent work and patience!
Cheers,

Eddie :)
Keep on Rockin' and DIYing!!!!

Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #48 on: August 18, 2009, 07:45:34 PM »
Let's do next, pay shipping back and fourth, and parts (if needed), I'll fix the pre.
http://www.ij-audio.com
(new site hopefully will be up in July)

SaMpLeGoD

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #49 on: August 18, 2009, 08:02:11 PM »
Yeah sure! I'll PM you tomorrow!
Eddie
Keep on Rockin' and DIYing!!!!


SaMpLeGoD

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #50 on: September 02, 2009, 10:54:31 PM »
Hello Igor,

Finally my friend gave me back my PGA2500 with the SMD chip re soldered... he said that he saw it at the microscope and all appears to be ok... I really don't know. Well, I did a small video regarding a PGA2500 test, as you can view in the video, the unit starts ok, all the voltages are ok, I can fully rise the gain from 0 to 75 (maximum) and go back. There's a relay action when I pass from the gain 19 to 20, I think it's ok, it should be some gain stage's relay acting... so far so good, but......
When I press the bottom's push button (phase I guess) I can just hear a relay actingand the PB light's up an down as it should be! ok but the middle button that is supposed to be the Pad button, acts like the 48V instead, when I press it not that but the top PB light's up! and when I press it back (the middle one) it the top led's light disappear... and the one who should be the 48V PB (top one) don't do anything :S
I check the flat cable, the connections the parts all seems to be ok... I don't know if is still something wrong with the PGA chip, or if I get it damage on my friend's resoldering... just don't know ...

I asked on the video but I'll do here, what about that molex 3 pin connectors? what's that for? should I connect between them? I saw the schematic but I'm not sure... sorry... I didn't realize how to regulate that trimmer on the main board, even don't know what's for... please just tell me if with this information you can help me... thanks a lot for your work and patience!

Here's the video link

Cheers!

Eddie  :-\
Keep on Rockin' and DIYing!!!!

Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #51 on: September 04, 2009, 08:02:09 AM »
Hi Eddie, 48V and PHS buttons behaves wrong, probably, there's a short between pins on pcb.
Check everything again.

Please see schematic. There's an option for insert and power supply,
the INS 10-pin dual row connector close to PGA2500.
Initially I thought to hook here extension to compressor or passive EQ. BTW, it is possible.
Connect (7 with 8 ) and (9 with 10) on INS conector.

There are OUT connectors. Take a piece of shielded balanced cable, Mogami thin cable diam. 3mm will be fine,
and connect OUT and OUT1. 1+  3-   2GND.

CMRR pot. After your pre is fine and passing sound, take two same precision resistors in range 4-10k,
I used 4k99 0.25%. Connect them to output next way: -out---R1---tie together---r2---+out.
Point where r1+r2 connected together watch on scope, feed balanced signal -30db 1kHz to preamp,
 gain 40dB, adjust for minimum CMRR. Balanced signal can be done with DI.

Hope this helps.
« Last Edit: September 04, 2009, 08:03:55 AM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)

iban

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #52 on: September 10, 2009, 01:16:21 PM »
Well, in the next link you can see my rack with two PGA2500 and with another two Access 312 kits. All is right working, but I have to adjust the CMRR in the PGA2500s. I don´t have scope, then, I don´t  know how I will do it  :-\

Thanks Igor for your support!!

http://www.flickr.com/photos/isialdi/sets/72157622330236258/

Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #53 on: September 17, 2009, 07:04:01 PM »
Hurray! Nice build. Will be happy to hear about your sonic impressions.
http://www.ij-audio.com
(new site hopefully will be up in July)

SaMpLeGoD

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #54 on: October 23, 2009, 10:26:44 PM »
Hi Igor, been busy lately! My PGA2500 are alive, all the buttons are working propertly, and the unit is passing audio, but when the gain reach the 20, I start to hear a high frequency sound, that raises with gain of course... at the 19 all quiet, when pass 20 I hear a relay and start to hear that... could this be related with the CMRR relugation? I still didn't regulate that!
Any clue???
Thanks a lot!!

Cheers,

Eddie :)
Keep on Rockin' and DIYing!!!!

Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #55 on: October 24, 2009, 04:33:01 AM »
Hi Eddie, this seems ground problem....please check the grounding scheme and connections.
http://www.ij-audio.com
(new site hopefully will be up in July)

iban

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #56 on: October 24, 2009, 07:33:45 AM »
SaMpLeGoD, I haven´t regulated the CMRR yet and I don´t have that high frecuency sound.

SaMpLeGoD

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #57 on: October 25, 2009, 05:22:00 PM »
Ahn all right then! Actually I didn't put the preamp inbox, I just tested outside... and of course I didn't wire the ground scheme yet!!
Thanks a lot!!!

Cheers,

Eddie :)
Keep on Rockin' and DIYing!!!!

zayance

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #58 on: November 16, 2009, 03:43:08 PM »
Hello Igor, is your stock for the pga project updated still 6 left? I would be interested in four plus PSU, thanks for clearing this out so i can purchase thanks a lot!

Igor

Re: PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.
« Reply #59 on: November 16, 2009, 03:48:08 PM »
I don't have PGA2500 chips right now; full kits...maybe, depending on interest, will be offered in next year.
The PCB's, controllers and PS pcb's are in the stock.
http://www.ij-audio.com
(new site hopefully will be up in July)


 

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