iprovlek

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #100 on: March 04, 2014, 03:33:06 AM »
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

 



Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #101 on: March 04, 2014, 04:08:28 AM »
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
« Last Edit: March 04, 2014, 04:12:23 AM by Gustav »

iprovlek

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #102 on: March 04, 2014, 05:53:46 AM »
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

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #103 on: March 04, 2014, 06:14:50 AM »
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...

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #104 on: March 04, 2014, 10:18:46 AM »
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

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #105 on: March 06, 2014, 10:35:11 AM »
Hi Gustav have you got one OA10 working?


Harpo

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #106 on: March 06, 2014, 11:17:38 AM »
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.
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.  -Douglas Adams

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #107 on: February 22, 2015, 03:19:18 PM »
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

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format)
« Reply #108 on: February 23, 2015, 04:50:08 AM »
Solved by reverse bc327&337.
the old bc327&337 are EBC and new CBE.
 :)

Re: Neumann OA10 discrete op-amp (in API 2520 etc. format) New
« Reply #109 on: October 08, 2015, 04:06:08 PM »
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
« Last Edit: April 25, 2017, 05:32:34 PM by electrochronic »


 

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