PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.

« **Reply #20 on:** February 25, 2009, 05:51:42 AM »

Ok, afterall I prefer the OPA2604 sound against the NE5532, I think it sounds clearer... just to my ears

I'm planning to fit a trimmer instead the Rx+ and Rx- resistors, so I can regulate the voltages to the preamp with more precision.
I'll go to the 25 - 0 -25 toroid

Thanks Igor!

Eddie

« **Reply #21 on:** March 12, 2009, 07:35:17 PM »

Hello Igor!
I received the kit thanks!!!!! Great work on this!!!
I have just a question: How is the PGA 2500 and the 4511 pin 1 orientation???

Just one more issue... I'm ordering some stuff from Banzai... I'll go for this transformer for running the preamps... is that ok?

Thanks a lot!!!

Eddie

« **Reply #22 on:** March 13, 2009, 03:10:07 PM »

Yes, exactly as red dot. Bottom control pcb is mirrored on drawing.
For 1...4 pre's possible to take 30W trafo btw, trunny on link is fine for powering up to 8 of pre's.

« **Reply #23 on:** March 13, 2009, 07:21:20 PM »

Thanks Igor!!!!!
Awesome project!!

Eddie

« **Reply #24 on:** March 13, 2009, 09:06:17 PM »

By the way Igor, the two 3300uF caps on the PSU board are 50V or 100V? exist a big price difference between them, just to know for sure...

Thanks,

Eddie

« **Reply #25 on:** March 13, 2009, 10:55:16 PM »

No way for 100v!!!
40-63 is enough!

« **Reply #26 on:** March 14, 2009, 07:46:02 AM »

Ok! Thanks!!!

Eddie

« **Reply #27 on:** June 25, 2009, 04:36:19 PM »

Hello Igor!

I finally finish my PGA2500, but I'm testing the PSU voltages right now and, have one question: I'm using OPA2604, so I need to get around +23VDC and -23VDC for PS-1 and PS-3 right?
I tested and it start to smoke my R3 that is the current limiter for the led, that is connected exactly between PS-1 and PS-3 giving me around 65V! so for sure it will start to smoke! I'll substitute the R3 for a 3K3 @ 2W resistor instead of the 10K @ 0,25W that is described in the BOM.
I'm leaving it open to test!
The PSU values I have, acording with the PSU Schematic are:

PS-1: +23DC
PS-2: GND
PS-3: -23DC
PS-4: +48VDC (phantom)
PS-5: GND
PS-6: +5VDC (for ICs)

Am I right with this tested values?
Thanks!!!

Eddie

« **Reply #28 on:** June 25, 2009, 04:54:53 PM »

Another issue... how should I regulate the 100k trimmer on the audio board? I have no Schematic and don't know what you mean with "CMRR"... and I really don't know about the jumpers... I'm leaving like you have in the photos, but I think is important know what they're for $:-\$
Can you post some more information about that??
Thanks a lot for this great project!!!!
Cheers,

Eddie

« **Reply #29 on:** June 25, 2009, 06:22:44 PM »

Hi Eddie, 10k 1/4w as current limiter for diode worked fine for me...strange. 3k3 is too low.
Here you can find all schematics etc:
http://www.groupdiy.com/index.php?topic=31783.0
(it is better to download schematic first

Regarding 100k trimpot on audio board: connect + and - out together thru two absolutely same resistors
(say 10k 1%), at this point should not be signal. Adjust it with CMRR pot for minimum.
Jumpers. Do it as on photos.
In general: if 0db jumper not installed, gain of pga2500 will be 0db.

There's 10-pin (2x5) connector, it can be used as "insert",
balanced in-balanced out, will not work good with unbalanced device.
Install two jumpers, one 7-8 and one 9-10.

A piece of balanced shielded Mogami etc wire will be helpfull to connect
out1 and out1-1, see schem.

Good luck!

« **Reply #30 on:** June 25, 2009, 06:26:46 PM »

BTW, if you use OPA2604, there should be 46V between PS1 and PS3.
Please check everything is OK before whole thing will smoke.
It is possible to desolder dead pga2500 and install new, but better no

« **Reply #31 on:** June 25, 2009, 07:04:47 PM »

Quote from: Igor on June 25, 2009, 06:22:44 PM

Hi Eddie, 10k 1/4w as current limiter for diode worked fine for me...strange. 3k3 is too low.
Here you can find all schematics etc:
http://www.groupdiy.com/index.php?topic=31783.0
(it is better to download schematic first

I used this schematic... I have 46.1 VDC between PS-1 and PS-3. I just realize that having 46VDC dropping 2V for the led, I must have 44V on the Limiting resistor... so, 2V with 0,02A current consumption I'll have:

R = 44 / 0.02
R = 2K2

P = 44 x 0.02
P = 0.88W (1W or 2W is ok) but I think 0.25 isn't $:-\$

If my math didn't fail... I'll need a 2k2 @ 1W to limit the current... talking about the other PSU voltages, I think all seems ok then!
I remove the "black" 10k resitor, the led don't ligh up, and everything is normal

The link for the audio board schematic is broken... can you get that available?
Thanks a lot Igor...

PS.: man... Michael Jackson has died...what a mess!

Cheers,

Eddie

« **Reply #32 on:** June 26, 2009, 06:47:29 AM »

Juste one question. Does the controller recalls the last settings? Flash memory?

« **Reply #33 on:** June 26, 2009, 12:43:36 PM »

Quote from: Igor on June 25, 2009, 06:22:44 PM

Here you can find all schematics etc:
http://www.groupdiy.com/index.php?topic=31783.0

Hi, Igor
I can get everything except the pre schemo

« **Reply #34 on:** June 26, 2009, 09:40:40 PM »

Quote from: abbey road d enfer on June 26, 2009, 06:47:29 AM

Juste one question. Does the controller recalls the last settings? Flash memory?

No... each power on, it returns to "0"

but mine isn't working propertly... don't know why...
Cheers,

Eddie

« **Reply #35 on:** June 26, 2009, 09:50:37 PM »

Hey Igor,

I finally finish my PGA2500, but it's not working propertly... the controler board, don't control anything, I pressed them and the top first and the second do the same, activate the phantom... visualy, because I hear no relays switching, and can't measure any 48V on the input's XLR pins 2 and 3. I can't hear no relays switching for the phase and the pad also...

I tested the flat cable, and it seems ok, but the control have a strange behaviour...
The one step db gain, works, visualy, I see the numbers normaly, but the light buttoms are crazy...
I soldered the PGA chip and the other one in the control board by myself... is in any way, clould be some bad soldering for the PGA SMD chip?

I think even it is bad soldered, the unit just doesn't work, bu the control board should be a normal behaviour... isn't it?
Really don't know how to start debugging it :S
Can someone help me please?

Thanks!

Eddie

« **Reply #36 on:** June 29, 2009, 04:06:58 PM »

OK, litle by little

Version of controller in these kits doesn't have a memory. It starts every time from 0.
The reason is if occasionally settings with phantom "on" or high gain stored, it can damage the mic or speakers.

Schematic link works perfect, from my home and work comuters.
It is huge .gif, may not work in Explorer.
Right click, save-as, open with acdsee ot whatever.

10k/ approx. 5ma seems ok for led, except it is not light show...at 20 ma most of led's are too flashy.

Yap, Jackson was Great Personality...never liked this kinda music anyway.

SaMpLeGoD, please let me know if display shows numbers and goes from 0 to 75 with turning the encoder.
Are pushbuttons working? (i.e. lighting their led's)?
Next step check the signals on cs, sdi, sdo, sck of PGA2500 with scope.
Check +/-5V as well.
Be sure 0db jumper is installed.
Be sure "insert" jumpers are installed.

« **Reply #37 on:** June 29, 2009, 04:08:49 PM »

The next step is checking voltages on input/output of pga2500. It should be 0v according to gnd.
Ceck every connection and every solder joint.

« **Reply #38 on:** June 29, 2009, 06:34:38 PM »

Quote from: Igor on June 29, 2009, 04:06:58 PM

SaMpLeGoD, please let me know if display shows numbers and goes from 0 to 75 with turning the encoder.
Are pushbuttons working? (i.e. lighting their led's)?
Next step check the signals on cs, sdi, sdo, sck of PGA2500 with scope.
Check +/-5V as well.
Be sure 0db jumper is installed.
Be sure "insert" jumpers are installed.

Hey Igor,

The numbers response is ok! they go from 0 to 75 and respond quick in both ways... the pushbuttons light up, but only the third one respond for pressing lightning up... didn't checked with the scope if it actually invert the phase, or even, I didn't check if some audio is passing...
The PB responsable for the 48V (Phantom power) sometimes light up sometimes don't, but the procedure that turns the gain into "0" and goes to the previous gain stored is working, but (I tested with the Multimeter) no phantom appears in the Input's XLR pins 2 and 3. the one in the middle makes the same as the phantom's one, but sometimes lighs up the phantom led, sometimes don't... the clip led is always lighted up... never goes down.

Can this be related with some PGA 2500 bad soldering?

Thanks for the help

Cheers,

Eddie $:-\$

« **Reply #39 on:** July 17, 2009, 12:26:46 PM »

Hi Igor!

I´m having problems with the kits. One of them apparently works, but there isn´t output signal in the xlr. Between pin 17 and 16 of Pga2500 there is 2volts with 75 of gain. Then, when I speak into the mic, clip-led shines and the output in these pins drops off.

The reles, buttons leds, 48votls on xlr, work perfectly.

What can I do?

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