neve 3126 box with photos

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soundguy

Well-known member
Joined
Jun 4, 2004
Messages
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NYC, USA
3126panel.jpg


finished this one up tonight.

3126top.jpg


Two 3126 EQ's with 283AM and Marinair L01166 for the output stage. Also has two 283AV's with sowter input and output transformers and my glide on fade awesome switch for input sensitivity.

3126rear.jpg


The wiring came out kinda hairy but leaded transformers are kind of a pain to work with. Overall the combo sounds really great.

dave
 
Looks great!

Do your 3126's have the BA437 amp blocks in them? If so, you may want to try swapping them for BA438's and compare the sound. I've never personally heard a circuit with the BA437 in it, but that circuit was a cost-saving attempt by Neve that is considered by many to be inferior to the BA438, particularly with respect to noise. The two are pin-compatible.

The '2' in the module number indicates that these were originally equipped with the 437. The BA438 version is a 3116.

If you have an opportunity to test this, please report back. I'm very curious to know if there is truth to the 437's reputation or if it's just more of the many Neve misconceptions.

Great job! :thumb:

JC
 
I'll check. they are kinda noisy to be honest.

I want to add an EQ bypass switch so Im planning on digging around in there in the future.

dave
 
BTW, did you follow Neve protocol with regard to the grounding and shielding? If not, this could also be a source of noise.

Basically, every feed to and from components (input transformer secondary to PCB, PCB to gain switch and back, PCB to fader pot and back, PCB to LO1166, LO1166 to output connector, etc...) should use shielded cable with the shield connected to audio ground (referred to as "B-" in all class-A Neve drawings).

As for grounding, the power supply's 0v should have one wire connecting it to the earth/ground pin of the AC wall connector and a second wire also from the PSU 0v to audio ground of the PCB's, input transformer secondary, etc. (just look at 1073 schematic to see what I mean).

Then, making sure that all sides of the chassis are electrically connected (Dremmel off some powdercoat on finished chassis to allow electrical connection all the way through the case), connect the chassis with one wire directly to the earth/ground pin of the AC wall plug. In this manner, the connection between audio ground/B- and earth/chassis ground occurs only at the single point of the AC ground plug.

Lastly, make sure to tie audio transformer cores to chassis, not audio ground/B-.

Oh yeah, and do NOT connect the B- and chassis pins of the modules together (pins E and V, respectively, on a 1073-type module). The connection between these two should ONLY occur at the AC wall plug ground pin. Lots of people argue with the need for connecting the two types of ground at the power inlet only, but trust me, if you are careful to do this, your noise floor will drop dramatically. Most people just jumper pins E and V on old channel modules and then connect that to both chassis and AC ground and figure it is the same as I describe above, but it isn't.

Coupled with zealous shielding, you really shouldn't have any noticable noise issues (unless the BA437's in the 3126's really are as questionable as I've heard).

Your two BA283AV circuits should be dead quiet though.

Please let me know if you have a chance to compare the 437 against 438's. Very interested.

Peace,

JC
 
jc-

will do.

when I say noisy, I mean "hissy" more than anything else.

It will probably be a long while before Im able to look into that but will check out whats in there for sure.

thanks for the tips.

dave
 
JC-

my modules have 438's in them, opened them up tonight. Recapped the 438's, seemed ot help with the issues I was having a bit.

437 mystery remains.

dave
 
What do you think about the sound from the Sowter channels compared to Marinair / Carnhill?
I built 12 channels of 1290 with Sowter irons for a friend who use to record all the male vox for the Roxette songs and he likes them alot!
Not that much character in the low end and a little more open up top.
oth vocal and acoustic guitar where recorded through 1290's on the last 2 Roxette singles. ( those songs looks to be the final chapter of Roxette )
 
The sowters are great. Probably the best of both worlds would be using marinair input transformers with sowter output transformers. the sowter input is great but the ouput is really awesome, its just clear as a bell in the bottom, but still big and the top is really smooth without being overtly present, it has that silky thing without the rolloff on top, big on the bottom without the mud. If I had to have only a 1272 type thing to use for every overdub on a record, Id definitely want it with the sowter transformers, they are much less cartoonish sounding.

dave
 
Quick question - did you fabricate the rails that the modules slide into, or didja purchase/salvage them from somewhere. Details would be sweet.
 
that second panel in the middle of the box comes with thhe par metal 12 series chasis. I just cut the holes in there for the edge connectors and the modules.

dave
 
[quote author="soundguy"]The sowters are great. Probably the best of both worlds would be using marinair input transformers with sowter output transformers. the sowter input is great but the ouput is really awesome, its just clear as a bell in the bottom, but still big and the top is really smooth without being overtly present, it has that silky thing without the rolloff on top, big on the bottom without the mud. If I had to have only a 1272 type thing to use for every overdub on a record, Id definitely want it with the sowter transformers, they are much less cartoonish sounding.

dave[/quote]
As in the Marinair-outputs being too dark & coloured w.r.t. Sowter outputs ?

Thanks,

Peter
 
Soundguy: Have you tried the carnhill output transformers? Im interested what you think of them.

/J
 
If I had a console with those carnhill outputs, I wouldnt have a console with those carnhill outs if you catch my drift. To stick in one box as effect, sure but I would want all my shit running through those things but then again I am an army of one so to speak. I think they sound really compressed in the midrange where the marinairs sound kinda cloudy in the bottom. Its pretty amazing what sowter did with their transformer in comparison. No, its not as colored. Thats a good thing if you ask me. All depends on what you are after. Hardly any risk like, *at all* to buy one of each and make your own mind up, the resale on those transformers aint budging.

dave
 
thanks!

I kinda like the compressed midrange of the carnhill. Or atleast i did when my preamps actually worked..lol

If i build more channels, ill definately try the sowters though!

/J
 

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