BCM10

[muffy1975]

HI there ,

I have built a bunch of 1073 line amp + eq pcbs . I however wish to add a fader before sending the signal to a bus.

What was used in the bcm10  post fader so to buffer the signal ? Was it the BA106 ? Attached below. I presume the signal path on the BCM10 was line in > 1073 EQ > fader > buffer> passive bus> BA283 > gapped TX.

Hope that makes sense.

regards

Michael

 

[ruffrecords]

There was no post fader buffer on the BCM10/2. The BA106 was a pre fader buffer. Attached is the schematic of the routing module.

Cheers

Ian

 

[muffy1975]

Thanks for your answer Ian. Looking at your attachment.....

Am i right in thinking with the  BCM10 that  the 1073 eq modules did not have a BA283 and TX output but went straight to a B106 then a fader then a summing resistor ( maybe 6.8K ) . All 10 channels? The output bus would be a BA283 with TX.

regards

Michael

 

[ruffrecords]

Thanks for your answer Ian. Looking at your attachment.....

Am i right in thinking with the  BCM10 that  the 1073 eq modules did not have a BA283 and TX output but went straight to a B106 then a fader then a summing resistor ( maybe 6.8K ) . All 10 channels? The output bus would be a BA283 with TX.

regards

Michael

AFAIK the 1073 modules in the BCM10/2 did have a BA283AV and an output TX. The unbalanced output from the 283 is the normal pick off point for routing module signal in most Neve mixers.

As you can see from the diagram I posted, post fader is the pan pot and Foldback send pot. These then feed the buses via 15K resistors. Gain make up is by a 1272 module via its input transformer.

Here is a link to the 1895 module doc that the schematic I posted was taken from:

https://drive.google.com/file/d/0B_n67A1hN3qtUi1IZHFJUHBidW8/view?usp=sharing

and here is a link to the BCM10/2 block diagram:

https://drive.google.com/file/d/0B_n67A1hN3qtMk04cVBtNGl4Zms/view?usp=sharing

Cheers

Ian

 

[muffy1975]

Hi Ian,

thanks so much for this. After reading it over at least 10 times I get it.

I was told the bcm/10 did not have individual outputs on each channel unless they were modified. In both cases I presume I am taking the unbalanced output after the HPF of the 1073 to the b106?  I have attached a picture of this connection


regards


MIchael

 

[Rocinante]

There's several guys on this forum plus other sites who do a Direct out mod to the BCM10 so that they can get all the Neve loveliness in each channel.  I think theres a dude with a pictorial of how he did it at JLM Audio.

 

[abbey road d enfer]

There was no post fader buffer on the BCM10/2. The BA106 was a pre fader buffer. Attached is the schematic of the routing module.

Cheers

Ian

That is kinda weird. Are you sure there's no active circuitry in the fader? If not, there would be a significant signal loss and variations with the pan-pot position and the number of bus routed. Neve is not known to cut such big corners...

 

[ruffrecords]

There was no post fader buffer on the BCM10/2. The BA106 was a pre fader buffer. Attached is the schematic of the routing module.

Cheers

Ian

That is kinda weird. Are you sure there's no active circuitry in the fader? If not, there would be a significant signal loss and variations with the pan-pot position and the number of bus routed. Neve is not known to cut such big corners...

Yes, I am sure; they were standard P&G 10K faders. I agree it is odd. However, this was Neve's very first 'standard' console.  I think they were conscious that they were at the top of the cost table so were looking to cut corners. I don't know why they did not just drive the fader from the unbalanced output of the 1073. You could then use the emitter follower as a post fader buffer BUT it is not meaty enough to drive the load of the foldback and pan pots. I think they should have used a BA283.

Cheers

Ian