Neve 1073 Module Build

Hi 

A while ago I bought 4 1073 cases from Beebird Audio and till now I didn't find time to finish them. I'm usually working as an FOH engineer and since there are no events in Austria due to Covid19, I decided to finish two of the modules.

Today I wanted to try the first channel, just with a BA283 in the module. I do get clean Audio in the first Amplifier Stage, the Gain Pot seems to work, but once it hits the second stage things do get weird.
First off all Audio gets super distorted and R7 gets really hot. So I think I messed up my +24V wiring.

I followed the original Neve schematic.

A --> 0V
B --> VTB1148 Pin 1
J --> connected to A and V
L --> External Fader
M --> +24V via 12 Ohm Resistor, VTB1148 Pin 3
N -->  +24V via 270 Ohm Resistor
P --> External Fader
S --> Connected to U via 18K Resistor
T --> Gain Switch
U --> Gain Switch
V --> Connected to J

What did I mess up? Does anyone have an idea?

Best wishes,
Johannes

UPDATE

I finally found time to post some updates on the modules. Everything is working fine now. As usual it was just a minor problem. Installed the trim pot on the BA283 board the wrong way.

Gain Stages are now all working correctly, EQ is working and I measured both modules and they are nearly identical. In lack of a real 1073 I couldn't compare them too, I thought it would be fun to see how different they are to the Waves Scheps73.

I will post some pics of the measurements later.  For now just some of the finished modules. Two more are already on the bench waiting for their transformers and pots

Cool. I like those Beebird frames. Did you make your own front panels?

Cheers

Ian

Whoa... what's this? Where do I get me some of THAT?!

Thanks Ian!
The frames are super awesome. The quality is really amazing. Never had the chance to grab a real vintage module, but it definitely feels like one.  No, the front plates were included with the frames.

@Ricardus
Those are frames and PCBs made by Beebird Audio. Bought 4 of those. 2 units already finished, the second 2 are waiting to be done.

Some more pics and screenshots of the measurements I did

Coop said:

Thanks Ian!
The frames are super awesome. The quality is really amazing. Never had the chance to grab a real vintage module, but it definitely feels like one.  No, the front plates were included with the frames.

Click to expand...

They are very reminiscent of the ones I saw at Neve back in the 70s. Odd about the front panels because the ones on their web site show their own logo not the Neve one.

Cheers

Ian

Yeah, the front panel thing is odd. But I'm still waiting for replacement ones because I originally ordered vertical ones. Will be interesting which logo they have on.

Any guess why my Low Frequency curves look so different compared to the plugin ones?

Around how much per module did these cost you to build? I’m interested in building a few.

I have 4 of the 1084 kits sitting on the shelf.
This is sparking my interest in starting the project.

@critterkllr
I'm not exactly sure but I think around 900€ per module, not including a PSU and a rack. I will write the exact costs down in the next couple of days I think

@Winetree
Do it I will try to post some sound samples soon. All recording sessions got canceled in the last weeks, but I do have a nice drum recording coming up in June.

Coop said:

Any guess why my Low Frequency curves look so different compared to the plugin ones?

Click to expand...

Plug in is a simple model of a complex system.

Cheers

Ian

ruffrecords said:

Plug in is a simple model of a complex system.

Cheers

Ian

Click to expand...

Oh yes that's right. It's a very complex system  At least for me, never built anything like that before.

Hey all,

I finally have time to share some more pictures and infos on the build. I recently moved my little mixing room to another location and finished building 4 more of the modules.

They now live in a custom made wood enclosure to be able to take them on the road for on location recording sessions.

Lovely woodwork and I am envious of your recording space. What kind of wood did you use and what finish did you apply?

I had another look at the LF boost curves you posted. The plug in seems to start boosting at a somewhat higher frequency than the 1073. Maybe they made a mistake.

Cheers

Ian

Thanks Ian! I try to take some more pictures of the wood case tomorrow.
I used beech and oiled it with linseed oil. Looks great I think.

I am pretty happy with my little space. Still some problems around 120Hz that I definitely need to solve.

Yeah, it reminds me of the test I once did with 4 SSL X-Rack EQs. To my surprise all of those 4 EQs where pretty different and the frequencies and cut/boost where quite off too. Completely different settings needed to match the hardware to the other hardware and to the Waves SSL EQ version. Need to search my drives if I can find some pics of the tests.

Coop said:

Thanks Ian! I try to take some more pictures of the wood case tomorrow.
I used beech and oiled it with linseed oil. Looks great I think.

Click to expand...

I agree. Nice colour and finish. I am no good at woodwork but my brother-in-law is. I plan to get him to make the wood side checks for the poor man's rube mixer so I am on the lookout for ideas of wood types and finishes.

Coop said:

I am pretty happy with my little space. Still some problems around 120Hz that I definitely need to solve.

Click to expand...

Probably because the width and height of the room are very similar. Maybe a could of bass traps either side of the window would help.

Coop said:

Yeah, it reminds me of the test I once did with 4 SSL X-Rack EQs. To my surprise all of those 4 EQs where pretty different and the frequencies and cut/boost where quite off too. Completely different settings needed to match the hardware to the other hardware and to the Waves SSL EQ version. Need to search my drives if I can find some pics of the tests.

Click to expand...

I wonder if this is because they are active types that do not use inductors? It depends on the equation that determines the frequency but if it is just proportional to the RC product then the tolerance of the frequency will be dominated to the tolerance of the capacitor. So a 5% capacitor will have a potential 5% variation in frequency. I an LC boost/cut circuit. the frequency depends on the square root of the LC product. In this case a 5% change in capacitance only causes a 2.5% change in frequency.

Having said that, I am not sure just how close console manufacturers get to the stated frequencies. The designer and accountants will want to use standard component values and not pay the extra for high tolerance types if they can get away with it.

As far as the boost/cut range varying, this is most likely due to the 20% typical tolerance in the value of LIN pots used in these EQs.

Cheers

Ian

I am not good at woodworking either. I wish I would have more knowledge and more tools to make it look even better. But it turned out really nice. I love the combination of nice wood and nice gear

Yes, bass traps in the corners behind the speakers will definitely be worth a try. Right now I do have a room correction software running, but it is doing too much. I'm fine if it adds or removes like 1-2db but right now it is doing way more. So if possibly I would love to get the room acoustically better in first place.

As for the SSL EQs. As far as I can remember the units where pretty close when I used small amounts of cut and boost. the more you did boost, the more it was off.

18dB Boost at 3KHz


15dB Boost at 100Hz, yellow is plugin, blue is hardware


More normal settings copied 1:1 from plugin to hardware, red is hardware, blue is plugin

I am not familiar with the SSL EQ controls. Are the boost/cut controls stepped or continuous?

Cheers

Ian

They are continuous

Coop said:

They are continuous

Click to expand...

OK, so setting them accurately is not easy and variability between pots could make a noticeable difference. I much prefer stepped EQ controls with resistor ladders but this needs a rotary switch which adds cost.

Cheers

Ian