mods on strip

[Kir_For_Pleasure]

have some spare channels to my mixer to play with but have some trouble to solve.

the mixer is full of these dinosaures

9 pin sip opamps and i want it to be 8 pin dip.
i need to make adaptor boards for this with 8 pin DIP to 9 pin SIP with one of the pins to carry the positive voltage.

If you can see any intresting mods to do, please tell me about them

 

[Guest]

Is it Yamaha?

 

[Kir_For_Pleasure]

Tascam m600

 

[Guest]

I think it is a good idea to make such small boards with 9 pins for SMD opamps.

 

[Kir_For_Pleasure]

thinking of the OPA 2228PA as replacer
WHY ?
much much faster and higher values than the originals
intresting to hear the diffrence !

heres the dataseet for the Njm2041

http://pdf1.alldatasheet.com/datasheet-pdf/view/7232/NJRC/NJM2041.html

 

[wmtunate]

I swapped out the SIL NJM4580s in my Tascam FW-1884 for OPA2228s. I whipped up 4 of these:

The mic pre in the FW-1884 has a very similar circuit. 2228s really seemed to help the dynamic range, and they lowered the noise floor noticeably.

 

[Kir_For_Pleasure]

what are the components doing on the adapter card must it be that complicated ?

 

[sonicmook56]

Looks like input protection diodes.

 

[Kir_For_Pleasure]

do i need thoose diods, the OPA2228 and NJM 2041 have the same input voltage.

 

[wmtunate]

The problem with the first few revisions of the FW-1884 was that it would tend to blow out input opamps when you hot-swapped mics with phantom power still on. They had to add input protection diodes (audio input, not supply voltage input). Yours probably doesn't need them.

That board I posted has more diodes than it needs. The ones I made only have diodes on the differential inputs.

Something like this would probably do:

http://cimarrontechnology.com/index.asp?PageAction=VIEWPROD&ProdID=34

 

[Kir_For_Pleasure]

Do you still have the board layout ?

 

[wmtunate]

No, I just drew it out with a sharpie.

 

[usekgb]

I have an FW-1884 as well, and would be interested in this mod. It's not that the pre's are bad, but they could be better. Do you have the circuit layout for that adapter board?

Cheers,
Zach

 

[wmtunate]

I just looked up the datasheet for the NJM4580 and matched up the pins to the OPA2228.

There's a webpage devoted to the mod here:
http://www.jb-2000.net/fw1884/

They've got documentation about the mod and complete schematics.

 

[usekgb]

Great. Thanks.

 

[Kir_For_Pleasure]

Thanks !

 

[Guest]

Behringer uses SMD 4580'th in his gear; they are decent though it is hard to solder 7.5K resistors on such tiny legs...