Marinair 31267 question / Neve 2064 update

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echorec

Well-known member
Joined
Dec 3, 2004
Messages
129
Location
Stockholm, Sweden
Hello,

I have a Marinair 31267 that I plan to use with a really old Neve EQ that only has unbalanced input.

I don´t have the pinout info of the 31267 so I don´t know how to connect it.

Any help appreciated.

Thanks.
 
Thanks Thomas.

I have very basic electronics knowledge, enough for recapping, racking modules and simple troubleshooting but nothing more. I have never installed a transformer in a Neve module.

Could you tell me to which pins I should connect my balanced line in and then the unbalanced output to the 2064 EQ? Any other components needed? Right now the old 31267 has a 22 ohm resistor & a small 2200 pF cap between pins 7 & 10.

BTW, hope the LA-3A is serving you well. I recapped all the cards in my broken 2254 and now it works almost perfect, just need to replace 3 resistors on the threshold switch.

Best regards,

Gunnar
 
echorec,

I think TK was suggesting that you look at the the 1073 schematic under the N*EVE info section of Dan Alexander's site. Yes, the numbers are hard to read but it does show how a 31267 was wired to a 1073 preamp/EQ module. The primaries are wired in series (connect 3 to 4, 5 = + in, 2 = - in). You can see also that the paralleled secondary windings (connect 7 to 8 for + out, connect 9 to 10 for - out) have a 2n2 (2200pF) film cap connected across as a zobel and are then loaded by a 2.2kohm resistor. This resistor is part of a stepped attenuator which the input signal is taken from via the wiper (pole) of the rotary switch. You can see that if we add up the other resistor values it is equivalent to putting that 2.2k resistor in parallel with a 1k resistor. Therefor, we can say the 31267 is loaded by approximately 690 ohms.

You could replace the switching network with a pot of this value or modify the input circuitry in a couple of ways based on your application needs and preferences. Generally there isn't a better way to do it than the original diagram specifies. The 2200pF capacitor is important for reducing excessive ringing of the transformer in response to a certain frequency. Fortunately you already have one. It's a mustard colored polypropylene film type, correct? I've been trying to find a good replacement for these, so if anyone knows of any?

For a better reproduction of the aforementioned schematic, go to http://www.technicalaudio.com/pdf/neve/ and click on 1073-EH10023.pdf

[EDIT] Just now I understood your connection question. As mentioned, pins 7 and 8 joined are the + output of the transformer. This gets connected to the unbalanced input (tip) of the EQ with the other side, pins 9+10, connected to COM/audio ground (sleeve). Don't forget that the 2n2 cap and network, pot, or equivalent resistor of ~690 ohms are in parallel with this connection.
 
Gunnar! Just give me call if you have any problems!

LA3 is working fine! haven't seen it in three weeks, rented it out the recording of Arch Enemy's next cd!
 
Hi TK,

I will probably get stuck somewhere and call you in the beginning of next week. I will try to mount this germanium/positive ground EQ into a little sidecar made for regular 1066 etc modules.

801456.jpg
 
Geoff Tanner would be the man to ask over at the forum on auroraaudio.net - he would probably be regarded as the guy that knows the most about Neve stuff since he worked for them for a number of years.
 
i know i am getting in too deep
when i look at that picture above - my eye is drawn to lovely blue and red knobs
swooonnn
 

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