Need schematics for Neve 33415, 33411 and 33310 modules

Does someone have schematics and infos for Neve 33415, 33411 and 33310 modules?
I figured out that 33415 was used as talkback micamp and lineamp, 33411 seems to be a line driver with external transformers and
33310 got to be some control-unit for a limiter? Any info about these modules and it's partners (like the audio-part of the compressor or limiter) would be great.
It seems possible to convert a 33415 to a mic preamp, any info or experience on that?

Michael

[quote author="Michael Tibes"]It seems possible to convert a 33415 to a mic preamp, any info or experience on that?[/quote]

There is no conversion necessary, the 3415 is a mic pre. They were used as buss amplifiers in neve consoles, neve used mic level in their passive summing mixers with 1272 or 3415 used for make up gain. Yes, they were used as "line amps" in neve consoles, but line level off the mix buss was actually mic level. The 3415 has a 10468 input transformer and a 338 and a 440 opamp. To use it as a mic pre all you need to do is put a pot between the two gain stages and you are basically set. You absolutely should install a -15 or -20dB pad if you intend to use it on a rock session, Ive actually clipped the input recording vocals with them, if you dont go through the hassle of duplicating the 1081 gain switch (which is overkill IMO) you'll want to have pads for sure. That was my first rack project years ago and Ive used those pre's on every single session Ive done since. Easy to do, no big deal, no complicated switching, no modification to the circuit what so ever, add the pot to the edge connector and you are done.

dave

I think I'd be tempted to do the 1081 gain switch design, though it could be considered overkill, but it would definitely give you the pad functions you'd no doubt need if you were going to really use it with any regularity.

JC

[quote author="rascalseven"]I think I'd be tempted to do the 1081 gain switch design[/quote]
Well, you're not going to pull that off without cutting traces, drilling holes, and flying wires from the modified PCB - not to mention changing components. Yes, that'd be a good academic exercise, but also a waste of time if your immediate goal is to use the thing to record microphone signals from most studio sources.

The 3415 schematic can be found here.

The extra 3 in 33415 simply indicates a different shade of gray, and thus a later revision, IIRC. Same goes for the rest of the modules you mention. The 3310 is indeed a simple limiter, -15dBm in and out, for use in the insert loop of input modules, IIRC. Full of 748 ICs and nothing to write home about. I suppose you could put that pre-fader when wiring up your 33415 the way soundguy describes. I can't remember what the 3411 does. There aren't schematics for these two on the web that I know of.

[quote author="Family Hoof"]The 3415 schematic can be found here.

The extra 3 in 33415 simply indicates a different shade of gray, and thus a later revision, IIRC. Same goes for the rest of the modules you mention. The 3310 is indeed a simple limiter, -15dBm in and out, for use in the insert loop of input modules, IIRC. Full of 748(?) ICs and nothing to write home about. I suppose you could put that pre-fader when wiring up your 33415 the way soundguy describes. I can't remember what the 3411 does. There aren't schematics for these two on the web that I know of.[/quote]

Thank you so much, that is a great help. The 3310 is an entire limiter, not just the control part? That would be great, at least it might be something usable - even if it's a bad sounding limiter it might find it's place. You don't happen to have any further info on it?

Michael

I have a pair of 3415s that I racked. I agree that the 1081 gain switch is overkill. What I did was use the resister values found on the 3415 schematic to change the gain of both amplifiers in tandem with a 2 pole rotary switch, I think I used a 2p6t switch. 6db per click (3db per amp). I also added a 2 position pad to the input, -10db and -20db. And, I also put a pot, acting as a fader in between the 2 amplifiers.

Actually, I guess that's pretty much the 1081 gain switch anyway, in'it? (almost).

While you may not need all that control, I find it nice to have all the variable textures available.

Jeff

thats the way I wired mine. I would reccomend boosting both amps simultaneously, I experimented quite a bit boosting one or the other or both, really makes a lot of sense to boost both...

dave

Oh, also, turn the trim pot all the way down. Otherwise the gain will be much too high and the output amp will distort very easily.

Jeff

Did you put the pad before the Tx or after ? and did you experiment with hotter levels whith the adding coulor when putting the pad after the Tx (as the original).
Cheers Bo

On mine the pad is on the input, before the transformer.

Jeff

The ones I racked I had the gain fixed and a 5K pot between the 2 sections, works great. Will need a 20db pad.
I would also short out the trim pot on the pcb, close to the front panel.

Hey, I´m still arguing about that you get different sound if you pad before
or after the Tx.There´s nothing wrong with it, but you have to feed the Tx with about 200 ohms to transform the way it was intended. What resistor values did you use for the 10 dB front pad?
Cheers Bo

Yes I do agree that padding before the xfrmr is different than a 1081, but I thought I would give it a try, and I can't complain. :thumb:

I can't remember the resister values offhand, but it shouldn't be too difficult to figure out. I did make a pad that reflects about 200 ohms to the x-frmr and about 1200 to the mic. In fact, I asked here how to do it, so if you do a search for my posts you should find the answer.

I also forgot to mention that on mine I replaced the output xfrmrs with LO2567's. So other than the placing of the pad, they really are almost 1081's.

Jeff

[quote author="Michael Tibes"]The 3310 is an entire limiter, not just the control part? That would be great, at least it might be something usable - even if it's a bad sounding limiter it might find it's place. You don't happen to have any further info on it?[/quote]
Yes, like I said, it is a limiter mean't for use in the fader loop of a channel amp or line amp module. unbalanced i/o, 0dB insertion loss. Here's the pinout:

3310

1 = input
2 = COM
3 = chassis earth
4 = output
5 = COM
8 = control voltage
15 = B+ (24VDC)
16 = B- (0VDC, COM)
17 = chassis earth