Neumann OA10 discrete op-amp (in API 2520 etc. format)

[iprovlek]

You are right Gustav!

I measured this two 337, 327 and pinout of this two transistor is like in the schematics!But it isnt!

I have ITT Cannon BC212B and BC182B transistor and they are the same as layout,while Motorola of this to transistor must be turn to 180!

I made 5 of this Opamp and they not worked ,and find here post where Audiox said that with this two 337 and 327 can be problems....so i flip them for 180

and they worked.....

This Opamp is amazing, I ordered Gar 1731 and will order 2520 and get some testing in my Studer 169!

I would very happy to see Preamp based on this Opamp...

Cheers

 

[Gustav]

You are right Gustav!

I measured this two 337, 327 and pinout of this two transistor is like in the schematics!But it isnt!

I have ITT Cannon BC212B and BC182B transistor and they are the same as layout,while Motorola of this to transistor must be turn to 180!

I made 5 of this Opamp and they not worked ,and find here post where Audiox said that with this two 337 and 327 can be problems....so i flip them for 180

and they worked.....

This Opamp is amazing, I ordered Gar 1731 and will order 2520 and get some testing in my Studer 169!

I would very happy to see Preamp based on this Opamp...

Cheers

Sorry, but just to make sure I understand what I am right about

I am 99.9% sure that I have to rotate the 327 and 337 I have to make the placement in the board correspond to the schematic, but what I am wondering is - are those parts depicted correctly in the schematic?

I would be happy to work on a preamp based on this opamp, but first - I need a working opamp!

Gustav

 

[iprovlek]

I think but not sure 100% that this two transistor isnt like in schematics!

Sending pic of this Opamp...

Used 1N4148 and BAV20 for diodes....

 

[iprovlek]

Looked to Farnell!

BC337(123,CBE)=Fairchild,Motorola,On semiconductor ,only Multicomp is (123,EBC)

BC327(123,CBE)= most of company is the same...

Maybe this will help...

When i started soldering and get not working Opamp, i checked all this comapnies and pinout of this transistors for OA10!And I measured all pinout,and

BC337 and BC327 allways confused me...

This can be consider...

 

[Gustav]

I found an original schematic, and even though I really don't understand the direction of the output transistors, they check out to be correct.

I also have an identical transistor layout to yours.

so I'll try it out. 

Gustav

 

[iprovlek]

Hi Gustav have you got one OA10 working?

 

[Harpo]

Looked to Farnell!
BC337(123,CBE)=Fairchild,Motorola,On semiconductor ,only Multicomp is (123,EBC)

look again, they all have the same pinout. The important part is the identification of the CBE pins location. The sequence of enumerating these pins is not standarized and often chosen depending on viewing angle.

 

[mrkrawn]

Hi
I have somes troubles with this DoA,
I have gustav pcb.
I put bc212b bc327 bc337
and replace bc182b by bc546b
i test it with +15v -15v in an eq to replace a ne5534  but no sound.
I follow the attached picture.
If someone know about that mistake please let me know.
I have other jensen and 2520 which sound great
thanks

 

[mrkrawn]

Solved by reverse bc327&337.
the old bc327&337 are EBC and new CBE.

 

[maxwall]

I know this is a old topic ,but I tried to build this for fun and it works well.  I made my own  PCB boards for this  DOA. 1.1in x 1.1in.  The resistor  R8 10R  burned initially , for unknown reason , along with T11 BC337 and chose a .5W resistor  in place of the original .25W resistor for R8. This solved the problem  for this mic preamp build.

T12 BC327, T11 BC337 leg orientation with my transistors are...... 1C 2B 3E  looking at front flat face of the TO92 transistor from left to right.

Here is a one page reference build guide I put together for those interested in trying this out.  Was easier to have this build guide near when soldering all components.  transistor sub list included in this guide with parts list. Handy to use when shopping for parts before the build.

Build Guide and Pics for viewing
https://sites.google.com/site/diypartsstore/tg-limiter-links/downloads

Note : This OA10 will not be stable when run as a single stand alone device in a 312 design. The output transistors cannot handle the high gain and current demands. This opamp requires that you use two devices, gain make up and gain boost for preamp use. Otherwise the output transistors sizzle very quickly.

If the design used output transistor like MJE181, 171 ( similar to 990 ) for output pair then it might be possible to run this opamp as a standalone gain device , in a single opamp design.

Note : My build guide shows (T12) BC327,  (T11)BC337 in correct orientation for  C B E

 

[JamesW]

Old topic but  this has finally risen to the top of my project pile. I can't view these docs  (Build Guide and Pics for viewing
https://sites.google.com/site/diypartsstore/tg-limiter-links/downloads ) .  Is it possible to get a copy electrochronic ?

I am also looking for another set of the OA10 boards they don't appear on  Gustav's site . I think that's where I got the first set.
I built the  studer 169 500  with the NE55340  opamp years ago and would like to try it with the OA10

 

[Fujirume]

Hi!! does this op amp can replace 2520 in the API 533?? I'm start building a copy of 533...thanks to all!!

 

[[silent:arts]]

Hi!! does this op amp can replace 2520 in the API 533?? I'm start building a copy of 533...thanks to all!!

yes

 

[STOERSENDER]

Hi there,
Is that a DOA that I might get in use with the project of Studer 169 EQ in API 500 format too?
https://groupdiy.com/index.php?topic=36522.0

Thanks and kind regards,
Boris

 

[gar381]

Check the CAPI store for my garxxxx(OA10).
These just might just be perfect for your EQ.

GARY

 

[rcphillips]

since I have quite a lot of time at home now (from our current COVID-19 pandemic), I'm finally getting around to building these opamps. I bought the PCBs from Gustav (iirc), and sourced the transistors from futurlec (both done ~10 years ago). I put female pin sockets in the too-large holes, and -thanks to all of the fire warnings in this thread- fired the first one up this morning with safety glasses on!

Result: sparks

In my case, T8 is now missing a bit of its casing, but nothing else looks burnt. I'm thinking that swapping T6/T8/T10 by 180 degrees is the correct thing to do here (given that those are all the BC182, and if one's wrong, then they all should be). Man, burning transistors smell __bad__.  : )

 

[Rob Flinn]

You could perhaps compare your transistor orientation compared to the circuit diagram.  I never found guessing stuff in this game worked that well.

 

[rcphillips]

Thanks, Rob. Yeah, that would be a sensible approach.
Do you (or anyone else reading this) know of a really good way to identify CBE using a regular (i.e., cheap) multimeter without a transistor testor? My last search on that topic didn't yield anything promising, and I don't have the datasheets for the transistors I'm using.

 

[Rob Flinn]

Do you (or anyone else reading this) know of a really good way to identify CBE using a regular (i.e., cheap) multimeter without a transistor testor? My last search on that topic didn't yield anything promising, and I don't have the datasheets for the transistors I'm using.

Not really.    You should be able to download the data sheets without any problems ......

 

[rcphillips]

I can identify the Fairchild transistors (I _think_ ; those have an F on them), but the others I really have no clue. There aren't any identifiable markings, and the manufacturer(s) wasn't stated on the invoice that I have.

Not a problem anymore, though - I built a second one and did the common thing of rotating T11 and T12 by 180 degress (so the bc337 and bc327 transistor are pointing opposite the drawing from the first post). Fired that one up, and sounds good!

<kermit_flailing_yaaaay>