Neve 10468 HI/LO Switch level difference?

[ruffrecords]

My other input question would be about instrument level, I do want a dedicated input for my bass guitar.
Is the line level ok at just 10k, I've read instrument impedance is 20k?
Yes I have several di boxes but just want to totally understand all my inputs.

Most guitars need a very high impedance input, typically several hundred thousand ohms or even as much a 1Megohm. For these you need a DI box or a special DI input which usually connects to a point after the mic input transformer.

Cheers

Ian

 

[Spencerleehorton]

If I was to build a di input into the neve 1290 preamp, would I do like this api-313 schematic and tap to output txf?

 

[ruffrecords]

If I was to build a di input into the neve 1290 preamp, would I do like this api-313 schematic and tap to output txf?

Unfortunately not. The API 2520 has a high input impdecance so it can be used for a DI input. The Neve preamps do not have high impedance inputs so you cannot do this.

Cheers

ian

 

[Spencerleehorton]

Ah ok , though there would be a hitch, I think what I'll do is adapt one of my api-312 to accommodate the instrument jack for di bass and di guitar.

 

[ruffrecords]

Ah ok , though there would be a hitch, I think what I'll do is adapt one of my api-312 to accommodate the instrument jack for di bass and di guitar.

That should work.

Cheers

Ian

 

[Tekay]

Neve 3415 had a -30dB input using two 4k7 reistors in serie with the input. No idea what it was used for.

 

[ruffrecords]

Neve 3415 had a -30dB input using two 4k7 reistors in serie with the input. No idea what it was used for.

It is a simple pad to create a 10K  alternative input. If you look at the notes on the schematic you will see that for a 10K input you need to wire a 470 ohm resistor across the normal input which creates a 26dB pad.

Cheers

Ian

 

[Spencerleehorton]

still a little unsure of how to wire these 10468 txf, should i be wiring them with 1:2 ratio or 2:1 for use with mic and line switching with the pad config of 2 x 4.7k and 150R?

and just so i'm clear in my head, the lower volume setting will be for line and higher volume for mic?

 

[ruffrecords]

The 10468 was designed to work 1:2 as a mic pre. It usually has a 4K8 or thereabouts secondary load. The reason for this is it gives the best noise performance with the NPN transistor used in the first stage of Neve class A mic pres.

Cheers

Ian

 

[Spencerleehorton]

sorry to harp on, but i just want clarity, i have the 10468 wired as 1:2, i am using 2 x 4.7k and 150R resistors on pad switch.
Is this now correct to run line level and mic level?

 

[ruffrecords]

sorry to harp on, but i just want clarity, i have the 10468 wired as 1:2, i am using 2 x 4.7k and 150R resistors on pad switch.
Is this now correct to run line level and mic level?

Yes, that should be fine. You need to set the amp following the 10468 to 30dB gain when using the line input to giver overall unity gain.

Cheers

Ian

 

[Spencerleehorton]

Ok lovely, Yes 3rd click on on the gain control gets me to unity,  and ive patched in the GS3000 valve channel into the patch bay now and this gives me Instrument input with valve drive, sounds good and dont have to mod any preamps!!

 

[Spencerleehorton]

I've also started to put together a list of all my rack gears input and output impedance, something I've completely overlooked.
I have Dbx 160, ssl 4K bus compressors, la-2a, pi 3141, 4 x 1176.
Going to label everything so moving forward there is no mismatching going on.

 

[Spencerleehorton]

Have just tested my Version of the 10468 input transformers and specs wise they come out great, testing later in pre amps.

 

[Rocinante]

If you go to the hairball site they have schematics you can download. On the Lola preamp he has a switch that switches the 10468 to be wired in either reverse for a line level or regular for mic input.  Basically you can use it wired as it's supposed or it gets switched to be wired in reverse and that works.

 

[Spencerleehorton]

Perfect, thanks dude, I've been wondering how that's done!