rafafredd
Well-known member
So, I got a bunch of nice transformers today (yes, more! And I know, I know... I´m sick), and some other things came on the same package.
I´m out of a digicam right now because I have already FU$$$D two of those. One just died and the other got a shower. So I´ve just the objects of this thread directly in my scanner. Sorry if the pics are bad...
Here they are:
Those are neumann discreet opamps. Ther are two plastic case and two metal cases. I´ve got the schematics on the Gyraf site for OA10, that seems to be different. Would anyone happen to have the OA12 schem?
This is a Point to Point board. Probably a line amp, with an opened OA12 there. I´ve reversed the board schematics, so I think I can reverse the OA12 schem also, if no one has it already.
The neumann board schem looks awfull to me. The opamp runs on a single power supply (probably +24v) and the opamp input is biased high above ground. I´m not a good circuit analyser, so forget me if I´m talking bullshit. I´m still very new in all this stuff.
So, Do you think this board is useable as it is, or should I take it apart and use the transformer and the opamp in another circuit? Maybe this neumann opamp would work just fine in an API kind of circuit??? I thinking about running this opamp with a dual power supply and get rid of both input bias and the 2.2uF input tantalum cap?
There was also a strange thing that came with all those nice trafos and opamps that I would love to know anything about:
As always, Thanks a lot!
I´m out of a digicam right now because I have already FU$$$D two of those. One just died and the other got a shower. So I´ve just the objects of this thread directly in my scanner. Sorry if the pics are bad...
Here they are:
![oa12_opamps_view.jpg](https://proxy.imagearchive.com/8dd/8dd83c1660d4e57155458ae7b56037cf.jpg)
Those are neumann discreet opamps. Ther are two plastic case and two metal cases. I´ve got the schematics on the Gyraf site for OA10, that seems to be different. Would anyone happen to have the OA12 schem?
![original_board_view.jpg](https://proxy.imagearchive.com/0a9/0a9c9c456c431d7e5f2e150bfa38605b.jpg)
![original_board_view_2.jpg](https://proxy.imagearchive.com/185/185f827152859d7c782ff04657e4c7a3.jpg)
![original_board_schem.jpg](https://proxy.imagearchive.com/660/6604eda31961ef56f9c35b59ef6e3d10.jpg)
This is a Point to Point board. Probably a line amp, with an opened OA12 there. I´ve reversed the board schematics, so I think I can reverse the OA12 schem also, if no one has it already.
The neumann board schem looks awfull to me. The opamp runs on a single power supply (probably +24v) and the opamp input is biased high above ground. I´m not a good circuit analyser, so forget me if I´m talking bullshit. I´m still very new in all this stuff.
So, Do you think this board is useable as it is, or should I take it apart and use the transformer and the opamp in another circuit? Maybe this neumann opamp would work just fine in an API kind of circuit??? I thinking about running this opamp with a dual power supply and get rid of both input bias and the 2.2uF input tantalum cap?
There was also a strange thing that came with all those nice trafos and opamps that I would love to know anything about:
![thing_back.jpg](https://proxy.imagearchive.com/69b/69b686d56174d28905986aa819da8081.jpg)
![thing_front.jpg](https://proxy.imagearchive.com/235/235c1642d1aeacada7f65b6fca3246c3.jpg)
![thing_side.jpg](https://proxy.imagearchive.com/ee0/ee031fa76dc1849817ad00866ed1f1c2.jpg)
As always, Thanks a lot!