neve 1061 schematic

[API]

Do you have some broken ones?
I can look in my boxes if you let me know how many you need.

 

[Arkestra]

I know this is an old thread but Im slogging through a similar rebuild with a b104/b108 combo. I got them here :

http://www.smallbearelec.com/servlet/Detail?no=1330

bought these and a few other European ones and tested all. Picked the ones that were around 80-100 and low leakage.
Guessing you found some but out of 10 about 3 were too leaky.

 

[Lee_M]

I'm thinking of building a couple of the B104 boards to use as makeup gain for a passive filter circuit, but I'm struggling to make out the value of the cap  between the base and collector of the BC109...

Is it 33pf?

Also, What power supply voltages do these boards require?
I'm guessing 24v, Is it bipolar or single ended?

 

[davemoog]

I am also building up/rebuilding some Neve B104 boards for gain stage after passive EQ. Any ideas how to set the trimmer on the B104 board - I'm guessing for symmetrical clipping or is there a specific current draw across the output emitter resistor??

 

[API]

I dont think there are any docs around for the B104 setup, but it must be for setting them for symmetrical clipping as you say to maximise headroom.

Also, these run on negative -24v

 

[davemoog]

Thanks API!
Yes, a similar setup procedure to the more modern silicone output stages by Neve seems to work OK. Hope these 50 year old germanium driver and outputs work for a few more years!

 

[API]

Great!

 

[Whoops]

thanks for the input.

does anyone have a source for AC 107 / NKT 216 germanium transistors or possible substitutes?

AC107
Replacements:
2SB257 ; 2SB389 ; 2SB39 ; 2SB443 ; 2SB46 ; 2SB73 ; AC151 ; AC164 ; AC191; NKT226

NKT 216
http://www.radiomuseum.org/tubes/tube_nkt216.html
Replacements:
AC107 , AC128, NTE158


Sources:

EBAY
http://www.donberg.ie/catalogue/semiconductors/semiconductors_a-ay/ac_107.html
http://smallbear-electronics.mybigcommerce.com/germanium-transistors/
https://www.banzaimusic.com/Germanium-Transistors/

 

[xazrules]

hi, i'm in the process of build a mic preamp based on a b100 first stage and a b104 driver stage and i have a question about the b104 schematic, in the bc109 (1st transistor) i see that the base is directly connected to ground is it an error? because if i try to simulate the circuit with it, it doesn't work but if i remove it work as it should.

thanks!

 

[PRR]

Has to be a drawing error.

 

[API]

Here is another slightly different schematic where there is no connection.

 

[xazrules]

Brilliant! thanks