JRE Productions

Fabio's 2520 R1 verses BC...which way do the pins go?
« on: February 06, 2006, 09:48:16 AM »
I just started stuffing the 2520 R1 and BC versions of opamps. I noticed that the boards appear to be mirror images of each other in terms of the pins.  So I assume that one will need to have the pins point the same direction as the components, and the other will point away from the componenets to get the to work the same.  Can anyone tell me which one goes which way?


Hope that makes sense!

Joe


pmroz

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #1 on: February 06, 2006, 10:06:00 AM »
.
R1 is designed like the original board. On the original, all the components are hanging off the bottom of the board, and the board is mounted upside-down, with longer legs going past the components on the component side of the board to meet the mounting sockets. You need long mounting legs (pins) for this one.

BC boards are made to fit components on top, and opamp pins/legs off the bottom.

If you mount them and look at the 312 PCB, R1 you should see the copper traces, BC should see components.

Paul

JRE Productions

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #2 on: February 06, 2006, 10:49:36 AM »
Awesome! Thanks for the quick response.  The 2520 thread and API threads are so long, I could not find the answers there.

Joe

Bauman

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #3 on: February 06, 2006, 12:10:57 PM »
:)
I am sure it's time to complie all that info and redo the 312 page to include it.
The sontec page also needs update :)

I need a 30 hours day right now :)

 :sam:
Fabio
cheers!
Fabio
_____________________
www.thediypill.com/store

kiira

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #4 on: February 06, 2006, 12:29:13 PM »
:?  What do R1 and BC mean?

Kiira

JRE Productions

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #5 on: February 06, 2006, 12:36:56 PM »
Kiira,

There was at least two versions of the 2520 opamp made by the same person.  One used transistors BC550/560 the other used some more obscure but original transistors.  So the boards are labels to distinguish the different revs or revisions.  R usually means revison 1, 2, 3, ect.  In this case I assume BC was to distinquish the transistors used.  So 2520BC uses BC transitors while 2520 R1 does not.

Joe

PS where abouts in Baltimore? I spend many a weeks there working downtown.

JRE Productions

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #6 on: February 06, 2006, 12:40:33 PM »
For anyone interested, I been trying to collect notes on these two projects:

I can not gaurentee any of this, but these were cut and pasted out of all the threads.

Quote
**Insulated wire goes from hole left of V- graphic (the one with white ring) to hole left of Q2
**Q4/Q5 = 1 x 80 or 82K resistor
**Did you all connect C5 above or below the PCB?

There are a few empty holes on these 2*5*2*0BC opamps:

**just below the printed 'C1'. On path between C1 (1000p) and C5. Don't see anything on schem that goes there...
**Also empty hole to the right of R9... to the right of the white ring, trace from R9 to V+. R9 should go right to V+ on schem so looks okay.
**GND pin to pre board is in, but hole next to it not connected. I see no ground on schem, only V+, V-, and O


oh, empty the holes...

- 1 in front of Q3 (between Q3 and Q9)
- 1 next R12 ( connected to V+)
- 1 next to R9
- 2 non-plated hoçes (1 next to 2520BC text and 1 next to C1)

and you need to connect V- in the middle of the board to a hole next to V- pin...


the GND on the opamp board is used for 100n caps between +v gnd and -v gnd.
I'm fitting mine under the board. This GND is also used by the original maker to shield the opamp, I have been told about some unetched board connected to GND over the opamp board.
Someone said that a metalic case grounded around the opamp is a good idea...

I think the empty GND hole was for the shielding... :)



Quote:
Re: shielding... CJ suggested covering the opamps with some case. At this point my plan is make boxes out of galv. sheet metal or sheet plastic, lined with copper foil, connected to GND on opamp.  


 
HEADS UP:
I did 8 different 25.20BC with different resistors and caps and transistors to test against api.25.20.


First impressions:
- R3 and R4 doesn't work with 82k as in the schematics. Use 20k!
- I think R2 needs to be 360R or 390R... will confirm but the best block I have tested
(#4, the one with the best stability and very near to API25.20) was the only one that had R2=360R. Those resistors are near the edge of the board, not hard to change...
- on 25.20BC, the background noise is a little bit higher that in the API25.20. Will try to mess with output biasing for the BD139/140 to see if it gets better. The best block (#4)
was done with 2N3053 and 2N4036 and was identical to my ears to the original 2.5.2.0.
when it comes to noises w/o input signal .


Right now I´m using C5=10pF and all the other caps like the schemo  . Try R2=390R also...





Quote:

2520 need some exchanging:  

this is for 25.20R1, 25.20BC and PP25.20 boards...

Quote:
R3 - 20K instead 82K
R4 and R5 can be too together 20K (or one resistor 20K )  

yes and yes :)

Quote:
R2 - 360ohm instead 100ohm
C5 - 10p instead 47p.  

 

Quote:
What to do with C2 and R10 and C3 and R14.  

dunno yet if we can remove this as stated on the schemo. The opamps
work great with this parts on,


i have a 2520bc rev1 in front of me right now.
there are 4 holes in one side.
top to bottom:out/v-/g/v+
v- has two holes.one for the pin,and another to jump to another hole close to r13.i made this connection with a piece of wire.


Which way do the pins go?

R1 is designed like the original board. On the original, all the components are hanging off the bottom of the board, and the board is mounted upside-down, with longer legs going past the components on the component side of the board to meet the mounting sockets. You need long mounting legs (pins) for this one.

BC boards are made to fit components on top, and opamp pins/legs off the bottom.

If you mount them and look at the 312 PCB, R1 you should see the copper traces, BC should see components.







Joe

kiira

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #7 on: February 06, 2006, 12:43:39 PM »
Quote from: "JRE Productions"
Kiira,

There was at least two versions of the 2520 opamp made by the same person.  One used transistors BC550/560 the other used some more obscure but original transistors.  So the boards are labels to distinguish the different revs or revisions.  R usually means revison 1, 2, 3, ect.  In this case I assume BC was to distinquish the transistors used.  So 2520BC uses BC transitors while 2520 R1 does not.


OK I see... I prolly have the BC ones (I hope). Fabio sent me some Melcors too.. they seem easier to make so I'lll start with them for my 312 board.


Quote
PS where abouts in Baltimore? I spend many a weeks there working downtown.


Not too far from downtown... up in funky (but not as funky as it used to be) Hampden.
Hamdenn in Bawmer, Merlann yanno? ?  

thanks!

Kiira

pmroz

Fabio's 2520 R1 verses BC...which way do the pins go?
« Reply #8 on: February 06, 2006, 01:04:09 PM »
.
Kiira, they're labeled R1 or BC on the boards.

 

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