DIY DUAL GERMANIUM MIC PRE-EQ BASED ON NEVE EARLY DESIGNS

[salomonander]

thanks a lot!
quote author=leadbreath link=topic=18356.msg790340#msg790340 date=1460075356]
hi

Ive got the originals from this thread, just bare with me and I'll upload them asap...
[/quote]

 

[Whoops]

I'm gathering information for this project.

As for the Germanium transistors used for each card:

- B100: OC44 (PNP Gemanium), NKT 216 (PNP Gemanium)
- B104: BC109c (Silicon), NKT216 (PNP Gemanium)
- B105: BC107a (Silicon), BC109c (Silicon)
- B101: NKT216 x2 (PNP Gemanium), ACY21 (PNP Gemanium)
- Outside cards: OC36 (PNP Gemanium), NKT216 (PNP Gemanium), BC107c (Silicon) ( The last 2 only if eq is added ).

These transistors can be found in some online suppliers or ebay,
on this stores:
http://smallbear-electronics.mybigcommerce.com/germanium-transistors/
https://www.banzaimusic.com/Germanium-Transistors/

as for equivalent PNP germanium transistors here is a list:

OC44 - http://www.radiomuseum.org/tubes/tube_oc44.html
replacements:
NTE126A , cv7003 are mil-spec made to higher tolerances , AC128 ,  NKT275, 2N527, 2N508, 2N404, 2SB75,  2SA49, OC440, AF239S

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

ACY21
http://www.radiomuseum.org/tubes/tube_acy21.html
Replacements:
ACY17, 2N1188

OC36
Replacements:
OC22, AL102, AD149

 

[Whoops]

It would be nice to know what should be the transistors requirements in terms of HFE and Leakage for these circuits.

Anyone has info on this?

 

[Whoops]

Some of the Neve modules with Germanium Cards

1053

 

[Whoops]

1055

 

[Whoops]

1057

 

[Whoops]

1058

 

[API]

B100 layout and parts

 

[API]

B104 layout and parts

 

[API]

B105 Layout and parts

 

[API]

Inside of a 1057

 

[API]

More 1057

 

[API]

More 1057

 

[API]

More 1057

 

[API]

1057 eq board

 

[API]

This one used a OC22 output transistor

 

[API]

1057 schematic

 

[Whoops]

1057 schematic

Hello API, thanks for the docs.

I also had the 1057 schematic unfortunately the resolution is so low that is unreadable, I have also a 1055 schematic that suffers from the same problem. There's a Wonderlandaudio post at page 7 of this thread were he posted those schematics probably at the time he didnt realized the resolution was really low at least for the 1055 and 1057 schematics.
The schemes for the B100, B101 and B105 at that post although also low resolution are readable.

It would be great to get readable schematics for the 1053, 1055 and 1057 modules.

I don't know which documents were at the link in the first post. is there any chance you still have the Binder1.pdf file? (http://groupdiy.silentarts.net/Wonderlandaudio/Binder1.pdf)

 

[Whoops]

The info I was able to get at the moment is that the Neve modules with Germanium transistors were the 1053, 1055, 1057, 1058, 1060 and 1061.

Those modules used a variety of cards, normally for the mic pre would be the B100 (germanium transistors) card.
Then for the EQ part and output part cards could be either Germanium or Silicon like the case of the B105.

- B100: OC44 (PNP Gemanium), NKT 216 (PNP Gemanium)
- B104: BC109c (Silicon), NKT216 (PNP Gemanium)
- B105: BC107a (Silicon), BC109c (Silicon)
- B101: NKT216 x2 (PNP Gemanium), ACY21 (PNP Gemanium)

As far as I know these were the cards each module used:

1053
1x B100 , 1x B101, 1x B101A, probably some more cards, anyone knows?

1055
1x B100, 2x B105

1057
1x B100, 3x B105, 1x B102

1058
1x B100, 2x B105, 1x B104???

1060
I have no info at all on this one

1061
1x B100, 2x B105, 1x B106???

Would be nice if someone is able to fill the blanks

 

[API]

The info I was able to get at the moment is that the Neve modules with Germanium transistors were the 1053, 1055, 1057, 1058, 1060 and 1061.

There are more, i think each number from 1053 to 1061 was used, then there are also eq only modules like the 2057 etc.

Those modules used a variety of cards, normally for the mic pre would be the B100 (germanium transistors) card.
Then for the EQ part and output part cards could be either Germanium or Silicon like the case of the B105.

- B100: OC44 (PNP Gemanium), NKT 216 (PNP Gemanium)
- B104: BC109c (Silicon), NKT216 (PNP Gemanium)
- B105: BC107a (Silicon), BC109c (Silicon)
- B101: NKT216 x2 (PNP Gemanium), ACY21 (PNP Gemanium)

Those are the basics, but i have seen other ones in them as well sometimes.

As far as I know these were the cards each module used:

1053
1x B100 , 1x B101, 1x B101A, probably some more cards, anyone knows?

I used to own a pair but have no pics of the cards, they could be earlier since i believe this was the first blackfaced germanium module.

1055
1x B100, 2x B105

It had a B104 output card as well.

1057
1x B100, 3x B105, 1x B102

Thats wrong, no B102 but a B104 on the output (at least in my module).

1058
1x B100, 2x B105, 1x B104???

Correct

1060
I have no info at all on this one

Same as the others.

1061
1x B100, 2x B105, 1x B106???

Again a B104 on the output.

Basically all the germanium Neves use the same cards, the earliest are the exception.
A B100 micpre, two or three B105 depending on how extensive the eq is and a B104 output card.