1073 EQ questions???

dukasound · Apr 19, 2005

Hi
Before a couple months I post a question about thi:
I watch EQ of 1073 and I find some difference in overall schematic and BA211 circuit.
On schematic presence switch is on OFF -position 1 connected in series with 4M7 with pin J on board. Than on position direct to J. Than in position 3 is wired to M, than H etc. Between all pins are 4M7 resistors to decrease switch pop.

On BA211 board After OFF position is U (there isnt on schematic), T, V, S etc.

Anyone can explain this. I wanna make old boards for EQ.
Thanks in advance
Duka

Tekay · Apr 21, 2005

Hi Duka!
It's the same circuit, this is the only BA211 schematics that I've seen and it's showing the complete mid circuit, exept for the anticlick resistors.
There's also a 7'th 10kHz position.
The amp is one of the stages from a BA284 board.

If you're thinking of just using the mid section , don't forget that the output will be phase reversed!

boodthee · Apr 22, 2005

Hi!
Dont take the switch drawings for granted. I would rather calculate the approximate resonant frequencies of the LC-combinations and then arrange your own switch assembly.

I think the BA211 schemo is little messed up: calculating frequencies for the T1530-part of the filter (using f=1/2*pi*sqrt(LC)) gives the following combinations:
C L F
22 0.7 1k5
47 1.2 700
100 2 360
So in the BA211 drawing the 100nF cap should go to J, 47nF to M and 22nF to H. And then "Off" next to H. That's the way Neve put it...but why not having the "Off" position on the other side of the switch...?

Cheers
Stephan

dukasound · Apr 23, 2005

Thanks to Stephen and Thomas
If anyone have pictures of both side BA211 it would be nice.
Duka

Tekay · Apr 23, 2005

Check here! Think you can find nice layouts here!
http://www.linear-recording.com.au/neve.htm

Stephan!
Thanx for the correction! haven't noticed that before. Not the first fault I've seen! 33609 manual states the first compressor recovery resistor value as 6k8! should be 24K.