Neve EZ1290 section on the PCB seems to not be used.

[777funk]

I did some experimenting today with my EZ1290 board and found that there seems to be a duplicate small signal section. The lower section (red square), I can remove the cap circled in black and it's as if nothing has happened and everything sounds great as before.

In the duplicate section above in blue square, if I remove the same cap (10uF), it interupts the signal as expected.

I'm assuming this cap is C8 in the schematic. But what's the deal with the duplicate circiuts? Why does the batch of components in the red square at the bottom of the PCB seem to not do anything?

 

[shabtek]

find 1290 1073 ba283 schematics and study

 

[777funk]

find 1290 1073 ba283 schematics and study

Is there one that has everything all in one page?

 

[ruffrecords]

If it is anything like a real Neve, one of the amplifier blocks is not in circuit at lower gains. Try the test again at maximum gain and see what happens.

Cheers

ian

 

[ratrace]

[...]• Gain is produced by two or three gain stages that are laid out true to the original BA183AV amplifier:
– BA183NV – the pre stage
– BA183AM – the driver stage
– at 55dB gain and above, a third pre stage (BA183NV) is switched in to supply addi/onal gain. [...]

Page 2 from the build guide.

 

[777funk]

Haha... That's what I get for skipping over the description when I built this thing years ago. Thanks!