Neve 80 series Console Build

[Whoops]

You can average 100ma per module, so around 6 amps for the whole console. What I meant is that it doesn't get hot. Which has the biggest impact on the bill: no need for AC!!

Even if you don't need HVAC system for PSU's or console, and even if you don't leave it on all the time what I wanted to say is that any new PSU will be more efficient than 50 years old Coutant PSU (late 60s/ early 70s), as we are in 2021 and you are building a new console at the present it makes sense to not go back in time and using a Coutant but using something better.

Best regards

 

[Whoops]

Some good info from Geoff Tanner about Neve PSU's:

"Hi

If we take the 1073 as a classic example, one of the biggest flaws in its design is that it takes the negative feedback for the output stage from the collector of the 2N3055 which puts it the primary winding impedance and a 12 ohm resistor away from the dc supply.

So, if you don't have gobs of capacitance after that 12 ohm resistor, then the noise and crud on the power supply can get into audio via the feedback. If you don't recap the modules in their lifetime and the electrolytics lose their efficiency you can get a situation where the signal in the output stages modulates the power rails, which is picked up in the feedback, and leads to "motor-boating" instability/oscillations.

So the power supply needs two thing...

1. Gobs of current headroom to accommodate the switch on surge of all those electrolytics charging up.

2. Absolutely damn all ripple and noise... if it measures -60dB (1mV) that's too much. It should be measured in microvolts.

So there's not really an audiophile power supply per ce, just very good ones with adequate current capabilities and minimal noise or ripple.

I'm amazed at how tiny some power supplies are for racks of modules. I'd allow at least 1 amp for two modules (1073's draw 122mA each) and at least 5 amps for a rack of 8."


https://www.gearslutz.com/board/high-end/185613-neve-10-series-psu-how-much-does-affect-sound.html

 

[zamproject]

"Some typical values would be: 4048 - 1700 Watts, a 4040 – 1500 Watts, a 4056 – 1900 Watts. "

Is that DC post regulation ? that's over 40A for +/-18 rail  ;D

My 70' studer have 3x 3A regulator, single rail 22V that's less than 200W max, and reg don't draw that many amp in use.

Remy should be around 150W regarding data he just give.

For sure "modern" big desk have lot of function/routing options but man what a fail in energy saving...

Regarding amount of time and money involved in this build, I'm with Whoops, it deserve to try a modern hiend SMPS, like industrial Vero PK series etc ...

Best
Zam

 

[Whoops]

Is that DC post regulation ? that's over 40A for +/-18 rail  ;D

That's Power consumption of the power line

1700watts x 230VAC = 7.39 Amps

 

[Winston OBoogie]

About 165mA for each router too if I understood the topology you went with correctly (2 X 283 output stages)

Plus the 1272's at about 90mA each.

Not efficient but, it's the price ya pay for class A with headroom 

 

[ruffrecords]

About 165mA for each router too if I understood the topology you went with correctly (2 X 283 output stages)

Plus the 1272's at about 90mA each.

Not efficient but, it's the price ya pay for class A with headroom 

I think Rupert's transformer stage is a bit better than 'classic' Class A. Everyone is taught that class A is at best 25% efficient, which is true for a a resistive collector load. But for an inductor collector load the collector can swing up to twice the supply voltage which gives this class A stage a maximum efficiency of 50% which is not that far behind the 70% you get with a typical class B stage. Probably exactly the same reason why the V72 et al use the same technique.

Cheers

Ian

 

[Winston OBoogie]

I think Rupert's transformer stage is a bit better than 'classic' Class A. Everyone is taught that class A is at best 25% efficient, which is true for a a resistive collector load. But for an inductor collector load the collector can swing up to twice the supply voltage which gives this class A stage a maximum efficiency of 50% which is not that far behind the 70% you get with a typical class B stage. Probably exactly the same reason why the V72 et al use the same technique.

Cheers

Ian

Yes of course.  I was allowing for this.    It's about the best we'll do with a 24V single rail.
Not all of the RMS signal swing comes from the stored energy in the choke/transformer too, we have 4dB step up from the 200:600 transformer.  Of course, this means the output transistor has to be biased for full RMS signal into a potential 200 ohms but, with just a +24V rail them's the choices. 

 

[Winston OBoogie]

For reference by others, what Ian means is that a single 24V rail would only be capable of max +18dBu in class A by itself. 

(24V/2)/1.414 = RMS voltage.

The inductor adds almost twice that so another 6dB.  And the transformer step-up adds another 4dB.

This is +28dBu max.

In practicality, the 1272 doesn't quite get double swing out of the choke load and there's a little loss from the step-up, so the max output signal is somewhere around +26dBu which isn't too shabby really. 

 

[Nickos]

Hi guys!
First of all... I think this project is the greatest thing I've seen on the internet so far! Thank you, it's so inspiring!

I don't understand the purpose of the T1310 inductor... If it's just to keep the load of the missing transformer, why it can't be replaced with a resistor?

 

[ruffrecords]

Hi guys!
First of all... I think this project is the greatest thing I've seen on the internet so far! Thank you, it's so inspiring!

I don't understand the purpose of the T1310 inductor... If it's just to keep the load of the missing transformer, why it can't be replaced with a resistor?

Because using an inductor (or transformer) allows the output transistor collector to swing up the twice the B+ rail. A class A amp with a resistive collector load it at most only 25% efficient. With an inductive load it can be up to 50% efficient. Rupert knew what he was doing. It is the same reason the old German preamps have inductor plate loads.

Cheers

Ian

 

[Nickos]

Thanks  Ian!
So, if i understand correctly, it will cause a lack of headroom, right?
It will affect the sound as well?

Nick

 

[ruffrecords]

Thanks  Ian!
So, if i understand correctly, it will cause a lack of headroom, right?
It will affect the sound as well?

Nick

Exactly, about 6dB less.

Cheers

Ian

 

[lotus]

Hi Ian, how are you?  I was wondering how the new tube console for Taylor Swift, for our place in Los Angeles is coming along?  And Winston O Boogie behave! And I might just give you a raise.

 

[Whoops]

how the new tube console for Taylor Swift, for our place in Los Angeles is coming along?

tell us more about that please

 

[ruffrecords]

Hi Ian, how are you?  I was wondering how the new tube console for Taylor Swift, for our place in Los Angeles is coming along?

I am not in a position to talk publicly about that right now.

Cheers

Ian

 

[remsouille]

Hey guys,
This is of no academic interest, but i just wanted to share with you a song that I recorded with the console yesterday.
https://we.tl/t-q2S2meJ9LG
Beware, this is me deliberately trying to not make a big sound ;D This is a 60's style band, so I wanted to keep it era correct and have more focus on tones, midrange and spontaneity than lo-end and mixing trickery.
But I think the console really sings for that kind of stuff, I'm loving it more everyday...
I can elaborate more on the recording process if anyone's interested, and though there is lots of very vibey gear involved, I very much hear the console on that one, so there you go!

 

[80hinhiding]

Hey guys,
This is of no academic interest, but i just wanted to share with you a song that I recorded with the console yesterday.
https://we.tl/t-q2S2meJ9LG
Beware, this is me deliberately trying to not make a big sound ;D This is a 60's style band, so I wanted to keep it era correct and have more focus on tones, midrange and spontaneity than lo-end and mixing trickery.
But I think the console really sings for that kind of stuff, I'm loving it more everyday...
I can elaborate more on the recording process if anyone's interested, and though there is lots of very vibey gear involved, I very much hear the console on that one, so there you go!

Incredible Remi!!  You are a first class engineer in my book.  When I first heard your samples in earlier posts I mentioned the desk having a thinner tone than I was expecting and like you say it really suits this 60s kind of style.  I'm sure you have no problem achieving a big sound too.  Your console and your engineering chops is something to use as inspiration to improve what I do.

Keep rocking bro!

 

[anguswoodhead]

Resurrecting this thread
I love when these old consoles get restored to their former glory
Last week I picked up 3 boxes of old parts from a 1971 8014
Cost me a pretty penny so sadly I can't give them away
Let me know if you need anything

 

[Kid Squid]

Hi Angus,
Keep me down for those cable extenders please - I did contact you on FB !
Best,
Steve

 

[Disco Volante]

It still acts as a voltage divider but the way it does it is different. The usual way to arrange a switched pot is to wire a string or resistors between successive switch positions. It looks and acts like a standard potentiometer.

The ELMA Jumbo is wired differently. It has a single series resistor wired from input to output. The switch then selects a different individual resistor from output to ground at each position. (see ELMA catalogue for details). This topology is for some reason favoured by audiophiles.

Edit: ELMA also supply PCBs for this switch that implement a conventional switched pot.

Cheers

Ian

Pardon me, I see this is a couple of years old...
The big downside to this arrangement is that if the wiper somehow loses contact with the "track" you'll have full signal out. I've had a few of these fall apart due to flimsy mechanical build...

Not so crazy about those ELMAs anymore, but the SMD version is one of the smaller in the market, if things are tight..
YMMV..
Love this project, hands down,

Cheers