PGA2500 KITS: AVAILABLE. BLACK PCB, SUPPORT THREAD.

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Igor

Well-known member
Joined
Jul 17, 2006
Messages
2,193
Location
Israel
Hi people!

Once I took a look on PGA2500 datasheet, it was some years ago,
I said "Hmmm....crap! Another chip pre? Nope!"
My bad taste is discrete, trafo-coupled, colored, etc. I'd cut my hand if I go to build chip-based pre!
Then, I heard evaluation board and said "Hmmmm....Too fast and clean to be truth!"
Many commercial pre's based on this chip appeared on market, like HV-3R, Prism Orpheus, etc.
Most of them are in very high priced range....
Well, there was PGA2500 thread on this forum...
I built a proto and was very surprised.
Studio people who tested this proto wery liked it as well.
This pre deserves name of an excellent clean preamp.
Use poly caps on input and good output stage, this is the cooking receipt.
And yes, it is possible to fit 8 pre's in 1RU.

Here's finnished, tested, fixed and polished final version of pcb's.


pga2500_audioSM.jpg



pga2500_contr1SM.jpg



pga2500_ps2SM.jpg



pga2500_pcbsSM.jpg



More hi-res pics, schematics, comp placement:

Audio board:

http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_audio.jpg
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pre_pcb_top.gif
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pre_pcb_btm.gif
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pre_sch.gif

Controll board:

http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_contr1.jpg
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_contr2.jpg
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_contr3.jpg
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/contr_pcb_btm.gif
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/contr_pcb_top.gif
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/contr_schem.gif

Power supply:

(can handle up to 8 pre's):

http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_ps1.jpg
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_ps2.jpg
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/ps_SCH.gif
http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/ps_pcb.gif

Whole thing:

http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_pre_full.jpg

PCB's hi-res:

http://i251.photobucket.com/albums/gg291/diy33609/PGA2500_KITS/pga2500_pcbs.jpg

Measures:

http://i251.photobucket.com/albums/gg291/diy33609/pga2500_meas.gif

I ordered 50 pcb sets...think they will go fast.

Ordering:

http://www.groupdiy.com/index.php?topic=29771.0

BOM, support, etc, coming soon.
 
I do not see the project listed on your ordering page:  http://www.groupdiy.com/index.php?topic=29771.0

How much will these be?

 
PGA2500 AUDIO BOARD BOM

Qty Value    Device              Parts
CONNECTORS
4            MOLEX-3            +/-U, OUT, OUT1, OUT3     
3            JUMPER 2 PIN        0DB, DCEN, ZCEN           
1            2 ROW 10 PIN          INS                       
1            3.81 PITCH MOLEX6    PS
1  NC3FAH  CON-NEUTRIK_AG_NC3    INPUT                     
1  NC3MAH  CON-NEUTRIK_AG_NC3.  OUTPUT
1            M2 ROW 8 PIN                SPI

MISC
4        FERRITE BEAD 10MM PITCH  L1, L2, L3, L4
1  100k 25TURNS  TRIM_RJ9W        CMRR

C-CERAMIC PS BYPASS           
5  .1U (47N-224) X50V 5MM PITCH        C1, C2, C6, C19,C20
6  224 (47N-224) X50V 5MM PITCH        C21, C22, C23, C24, C29, C30

C-POLY
2  u47    7.5...10.5MM WIMA      C9, C10
2  1U      7.5...10.5MM WIMA      C7, C15

C-POLY OR SILVER MICA
4  33p      5MM WIMA              C11, C12, C27, C28         
1  100p    5MM WIMA              C13                       
2  330p    5MM WIMA              C31, C32
1  1N      5MM WIMA              C33

C-TANT 10V 2.5MM PITCH
3  10...47U      C3, C4, C5

C-LYTHIC
1  100u_63v  PITCH 5MM        C8
2  220-330UF 35V PITCH 5MM      C14, C16
2  50u 35V PITCH 2.5MM          C25, C26

INPUT CAPACITORS
2  6.8..10u 63v  POLY  CIN11, CIN21
    OR AXIAL/RADIAL LYTHIC 10...47 UF 63V

RESISTORS 0.25W MF 7.5MM PITCH
1  3r3      R-EU_0204/7        R36
4  10r      R-EU_0204/7        R4,R11, R12, R16, R17       
2  50r      R-EU_0204/7        R24, R25
1  120      R-EU_0204/7        R10
1  340      R-EU_0204/7        R6
2  1k33    R-EU_0204/7        R5, R7                     
3  4K7      R-EU_0204/5        R20, R21,R43                       
2  6k8      R-EU_0204/7        R8, R9                     
4  8k66    R-EU_0204/7        R30, R31, R32, R33         
4  10k      R-EU_0204/7        R34, R35, R41, R42                         
6  30k      R-EU_0204/7        R22, R23, R26, R27, R28, R29
2  3M3      R-EU_0204/7        R13, R14

RESISTORS 0.125W NON-MF
4  10k      4X10K PULL-UPS                RN1
4  4k7      R-EU_0207/2V        R37, R38, R39, R40

SEMICONDUCTORS
4  *        1N4148.            D1, D2, D3, D4
4  PN2222 OR    2N3904  Q1, Q2, Q3, Q4
1  78L05    TO-92              IC2                       
1  79L05    TO-92              IC3                                             
1  OPA2604  OR NE5532          IC1                       
1  PGA2500  PGA2500            U1                         
                     
                   
RELAYS
4X NAIS TX2-5V      HPF,PHASE,PAD,48V
Order Code: 1148605
 
BOM FOR CONTROLL PCB

Qty Value            Device              Parts

CONNECTORS
2    9 PIN PCB INTERCONNECT  M
2    9 PIN PCB INTERCONNECT  F
1    M2 ROW 8 PIN                SPI
1    FLAT CABLE WITH 2X8PIN CONNECTORS, ~150MM

CAP-CERAMIC
2    0.1-0.22 UF 50V 5MM PITCH      C2, C1
2    15N 50V 5MM PITCH              C13, C14
CAP-LYTHIC
1  220u 10v      3.5MM PITCH      C3
RESISTORS                                                 
13  10k    0.125W 5MM 5%        R8, R9, R10, R22, R23, R24, R25, R28, R29, R42, R43, R44, R45
12  470    0.125W 5MM 5%        R1, R2, R18, R19, R20, R21, R26,R3, R4, R5, R6, R7                             


3      2N3904 OR PN2222                T1, T2, T3
1  LED3MM          RED LED3MM            CLIP                                                       
1  PGA2500-CONTROLL PRE-PROG'D PIC        U$2

1  4511D            4511SMD                IC4
Order Code: 9666532

3  MEC SWITCH      3F1D MEC            48, HPF, PHS
Order Code: 1132902

3  SWITCH CAP
Order Code: 1132951

1  ALPS_ENC      ROTARY ENCODER        RE
Order Code: 1520809

2  HD-F103      7-SEG CC LED DISPLAY    X1, X10
BLUE: Order Code: 1200600
OR: HDSP-A403, HDSP-A153, HDSP-7503 HDSP-7403 HDSP-7803, HDSP-A803 ETC.
                                                         
 
PGA2500 POWER SUPPLY BOM

Qty Value     Device         Parts                     
CONNECTOR MOLEX 3.81MM X6                         
1             MT6-6Y         PS                         
                       
DIODES
6             1N4004         D1, D2, D3, D5, D8, D10   
4             1N5400         D4, D6, D7, D9             
2             1N5822         D11,D12

CAPS-CERAMIC
6   0.1       50V 2.5MM         C9, C12, C14, C15, C20, C21
2   0.1       100V 7.5MM         C2, C4                     

RESISTORS
1   10k       R-EU_0207/10   R3
3   200       R-EU_0207/10   R1, R4, R7
1   rx+       R-EU_0207/10   R5 FOR 24V, USE 3K57; FOR 18V, USE 2K7 
1   rx+       R-EU_0207/10   R2 FOR 48V, USE 7K5
1   rx-       R-EU_0207/10   R6 FOR 24V, USE 3K57; FOR 18V, USE 2K7

CAPS-LYTHIC                       
4   100u 50V     3.5MM PITCH  C10, C11, C13, C16         
1   100u63v      5MM PITCH   C5                         
1   33-47u 100v  5MM PITCH C3                 
3   220u 100v    7.5MM PITCH                   
1   1000x10v     5MM PITCH                         
2   3300u        10MM PITCH                         
                         
IC, MISC                       
1   317       LM317TS                               
1   337       LM337TS                               
1   783       TL783                             
1   LM2576_5V                 
1   INDUCTOR 100-150UH 1.5-2A       
2   HEATSINK                                   
                       
                         
 
thought it was just my sister in law that likes to make big entrances, but no, seems the whole of Israel likes to do this :) :)

stunning (as usual) looks like bankruptcy is fast becoming a reality for me, and looks like i shall put a small marker at your door as partly responsible ;D

Iain
 
This is excellent!
After waiting two years for this, I almost lost hope that someone will write the code to controll the PGA2500. ( http://www.groupdiy.com/index.php?topic=2148.0 )
By the way, the preamp I was talking there was the Lavry Blue mic preamp (based on the PGA2500) ( http://www.lavryengineering.com/white_papers/4496-2-01.pdf ) and it sounded cleaner than some other very good, clean preamps like the Cranesong, Millennia HV3D and DAV.


I have a question Igor.
I have my different idea of designing the front end and the output buffer for this preamp, so I do not need the preamp PCB. There is any chance you can sell only controller boards with programmed microcontrollers? If yes, how much would they cost?
Please, say yes. ;D

chrissugar
 
Depending on how many boards you need. I have to brake a pcb set for this,
or make a batch of controller's PCB's only.
 
Probably 8 for starting but maybe more in time (up to 24). Can you give me an estimated cost?
Many thanks.

chrissugar
 
For 8 controll boards with PIC's, it will be EUR22/set. For 24 controll boards, EUR17/set.

@3nity: take only pcb's+PIC, and order the rest by yourself,
it comes up a bit cheaper if you don't count in time spent to
order all parts and shipping cost.
 
Hmmm, very very tempted to buy 24 from the begining because of the price break. Although I don't know if I can afford at this moment to invest over 400eu only in the controllers.
Will think about it and tell you what I decided.
Thanks again.

chrissugar
 
After reading again what you wrote here:

Igor said:
I have to brake a pcb set for this,or make a batch of controller's PCB's only.

it made me realise that maybe it is better to ask if you would sell preprogrammed microcontrollers, because that way you don't have to break PCB sets.
Also shipping of the chips would not depend on waiting for PCB fabrication.

Thinking about it, it became clear that it is not absolutelly necessary for me to have the controller board. I will not include the polarity, high pass filter and pad switches in my preamp so I can also make my own simplified version of controller pcb, with only gain control and phantom power.
What do you think?

chrissugar
 
Wich Toroid do you recommend? some 18 - 0 - 18 at the secondary?
This one here will work? 30VA is enough for 4 pres?

Why do you suggest that the PSU could be 18V or 24V? is any related with using NE5532 or OPA2604? please let me know :)

Cheers!!!!

Eddie  ;D
 
Kits comes with opa2604, my guess is to run them from 22-24V.
Farnell have some nice 2x25V toroids, cheaper a bit than EUR20.
30W is enough.
If 5532 will be used, 18-0-18 will work, just calculate power supply resistors,
for 5532 it should be 18V.
The logic is very simple:

if output is 18V, voltage drop on 200R is 1.25V and on Rx is (18-1.25)V...

(200/1.25)=(Rx/16.75)

Rx in Ohms

The rest is plain math.
 
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