What Ics to use on a Neve V series ?

[xarolium]

Hi there,

I know what you think, an other topic on Neve V serie mods but i need to understand something and you can help me.
I 'm thinking of replace ICs in my Neve VR36 to reduce temperature, power consumption and remove electrolytic capacitor between stages.

My question is why if i use modern op amp like OPA1662 or OP1692 to replace the old NE5532 i can remove the 100uF caps between each stage of the circuit ?
Does it mean that i can remove all those caps if i replace the TL074 with OPA1664 (or equivalent). What op amp can be used ? Modern one, like OPA16XX series ?

Then i also read that in the EQ section i can not replace all ICs, particularly IC10 with modern op amp cause it will "sing like a bird". and that some replace the 10uH ferrite chock with ferrite beads, why ?
If some body can take some time to explain me that thing i would be grateful

Thank you

 

[garp]

The whole thing is calculated with 5534 i'll personnaly stick with it, i tried this on my ex SSL4000 and it was a flop, except redesigning the whole thing i'll not play with mods, specially on the eq ! No mention that i loosed one harm with one kilogram of analog device chips

 

[xarolium]

Garp,
What do you mean by "a flop". Was the SSL4K not working properly after the Op Amp mods ?
It seems that "guru guys" like Jim Williams or Musgrave made this mods.
Have a look on this topic https://repforums.prosoundweb.com/i...HPSESSID=0unba3qdgmg0d3qs893f28qouh#msg531354

 

[garp]

A flop means that strange behaviours and oscillations occured on extreme settings without any sonic improvement

 

[JohnRoberts]

In general I dislike amateurs second guessing professional design engineers, but some people have too much money and too much time on their hands. At least DO NO HARM.

My general advice is measure twice and only cut once. Rigorously bench test the audio path with very basic measurements like frequency response. Maybe after that measure noise and distortion. Older SKU mostly suffer from dried out electrolytic capacitors. These can often be identified by weak LF response. When you find one or more bad ones, replace all the same make/value capacitors as they are likely on their last legs too.

Off the shelf ICs by the late 70s were already faster/better than typical audio requirements so properly executed designs for the last several decades should be pretty competent. Caveat not every old design is competent but many that weren't were identified back then.

JR

 

[garp]

Or DO HARM and then hire skilled technician !

 

[Michael Tibes]

I believe that there might not be a simple answer like swap this with that. If I was to try something like that I'd evaluate every stage and look for suitable replacements for each stage, maybe even use additional circuits for dc coupling. It would be a big research project - and it would certainly not sound exactly the same afterwards.
I wasn't aware that there were that many 074s in a V, wow!

 

[pucho812]

Musgrave made his bread and butter doing his mad labs upgrades to the v consoles. They are nice. But as memory serves he did not swap out the 5534’s/5532 unless broken.

 

[Matt Syson]

Swapping individual chips in specific places CAN be an improvement BUT as soon as you do so you have taken full responsibility for reliability and all other aspects of the gear. If it is yours and you can afford the mess all well and good. AMEK and Calrec separately and in different circumstances learned that faster or supposedly 'better' chips can and DO rather strange things if you use a lot of them. Possibly artifacts of the PSRR capabilities of different chips which when combined with the physical board layout can turn one or more into oscillators. Also the term 'unity gain stable' is conditional on external loading and power rail isolation between stages.

 

[JohnRoberts]

Swapping individual chips in specific places CAN be an improvement BUT as soon as you do so you have taken full responsibility for reliability and all other aspects of the gear. If it is yours and you can afford the mess all well and good. AMEK and Calrec separately and in different circumstances learned that faster or supposedly 'better' chips can and DO rather strange things if you use a lot of them. Possibly artifacts of the PSRR capabilities of different chips which when combined with the physical board layout can turn one or more into oscillators. Also the term 'unity gain stable' is conditional on external loading and power rail isolation between stages.

I joke that large consoles are the most complicated "simple" circuit designs. The individual circuit blocks are almost trivial, but throw tens of them together inside a single chassis and stuff happens.

JR

PS: I make a similar joke about audio power amps that appear simple, until you design one.

 

[neve2254e]

This may sound silly, however it might be more ideal to put in a better air conditioning system. Also there are some air flow mods you can do to improve the tempurature of the console.
I also put a seperate AC system for the power supplies, or invest in a switching power supply.

 

[JohnRoberts]

This may sound silly, however it might be more ideal to put in a better air conditioning system. Also there are some air flow mods you can do to improve the tempurature of the console.
I also put a seperate AC system for the power supplies, or invest in a switching power supply.

it was not uncommon to see a bunch of power supplies racked up inside an air conditioned closet.

JR

 

[Walrus]

Yes, the best way to reduce power consumption is to replace the Neve supply with a switcher like the Mpower one from Malcolm Toft https://www.malcolmtoft.com/mpowersystems
Then you don't need any cooling for the supply.
How old is the desk? Does it have the perforated cover panels.

 

[kags]

This may sound silly, however it might be more ideal to put in a better air conditioning system. Also there are some air flow mods you can do to improve the tempurature of the console.
I also put a seperate AC system for the power supplies, or invest in a switching power supply.

We have 4 studios, each with one HVAC system for the machine room and one or two for the studio areas. Then separate units for common areas and offices. AC maintenance is a large but necessary expense.

We did switch to Atomic supplies for our three large consoles, but we still have lots of class A amps and computer gear that needs to be cool and dry.

Don’t skimp on AC. I just spec’d a 5-zone $50k HVAC system for a 600 sq foot studio. )But, it is in a very humid climate in norther Thailand. )

 

[neve2254e]

it was not uncommon to see a bunch of power supplies racked up inside an air conditioned closet.

JR

Absolutely. I went into a 60 channel Neve V3 studio to consult and they put their power supplies in a closet with no AC. The air temperature in the closet was over100 degrees. Of course a month later he called me back and said that the power supplies caught on fire.

 

[Rob Flinn]

I was working at a facility with a single large AC unit in the machine room. The AC unit failed & it was a big problem to put a temporary system in while waiting for parts. They had to make a panel with a hole in it where the door was to evacuate the hot air from the temporary system. In some ways it is better to use 2 smaller systems so that if one fails you're not left with nothing.

 

[abbey road d enfer]

There are probably a few positions where eliminating electrolytics would do no harm. E.G. C24 and C33.
Now your choice of opamps seems adequate but you would need to do it one channel at a time.
You would need adapters since they are available only in SMD.
The decoupling caps are not apparent on the schemo, so you must be prepared to add some.
You may have to watch those opamps that don't have a lead compensation cap (IC15).
I must commend your approach, which is to improve reliability and comfort of use, when so many roll opamps for the sake of "improving".

 

[xarolium]

Walrus, my board has perforated back panel.

Abbey road, thank you for your advice. Of course i will start by one channel and make some audio test.
I already order smd to DIP adaptor with OPA1662 (by the way if some of you need OPA1662 on DIP adaptor, PM me)
I think i will keep the TL074 (IC15) and replace only the 5532 that draw lot of current.

I also want to replace the Power supply with digital one but not the huge expensive one present on the market. I'm thinking building my own digital PSU with Mean well modules and extra filters. I will save lot of money .

I also look at the cooling system using 3x 140mm fan on the back of each bucket.

 

[pucho812]

the biggest and I do mean the achilles heel of those Neve desks is temperature.
It gets well over 100 degrees underneath the surface in a stock unit. In turn this causes the plastic switch cams to get brittle and fail so your switches will not latch. It causes capacitors to dry up and fail which can cause all kinds of issues from eq's not working to any number of other related problems.

Even with a new SMPSU the desk still has ventilation issues by design.
See if you can find info on the ICE mod for the Neve V series. At one point there was an engineer who created the ICE MOD which dropped the temperature under the surface by over 20 degrees. This put it close to 85 degrees under the surface.

At a studio I worked at, we left the back panels off the desk which seemed to help alleviate some of the thermal issues. However I can't say for certain how much it helped because the desk was a mix of mad labs upgraded modules and non upgraded modules. As it was never completed the desk seemed to misbehave more often then one would think it would.

Years later at another facility I took care of 3 x VR's where we left the back panels on and they were not perforated. I can't say if that made things worse or not.

 

[SIXTYNINER]

the biggest and I do mean the achilles heel of those Neve desks is temperature.
It gets well over 100 degrees underneath the surface in a stock unit. In turn this causes the plastic switch cams to get brittle and fail so your switches will not latch. It causes capacitors to dry up and fail which can cause all kinds of issues from eq's not working to any number of other related problems.

So f.............. true !
(unfortunately)

Years ago a musician friend showed me some photos
regarding tracking and mixing sessions
in a studio with a quite large VR console
(..if not wrong.. , had to be a 72 channels)
used also as a "food warmer",

on which were placed tightly well sealed thermal containers with lunch inside,
resting on top of metal supports with rubber feet
that kept them within a few centimeters of the surface of the console,
so that they would not get cold.

Even with a new SMPSU the desk still has ventilation issues by design.
See if you can find info on the ICE mod for the Neve V series. At one point there was an engineer who created the ICE MOD which dropped the temperature under the surface by over 20 degrees. This put it close to 85 degrees under the surface.

At a studio I worked at, we left the back panels off the desk which seemed to help alleviate some of the thermal issues. However I can't say for certain how much it helped because the desk was a mix of mad labs upgraded modules and non upgraded modules. As it was never completed the desk seemed to misbehave more often then one would think it would.

Years later at another facility I took care of 3 x VR's where we left the back panels on and they were not perforated. I can't say if that made things worse or not.

A possible solution
would be to set up a dedicated flow of filtered dehumidified air under the desk
(when the control room is in the planning stage, or where possible mod it later)
coming from the central air conditioning system
constantly monitored by the dedicated devices with anomaly alarms,
(to prevent poorly dehumidified air from coming in
which would produce harmful condensation)

and yes the console back panels perforated help a lot
and so much more with an appropriate number of super silent fans
that draw heat from inside the console
directing the hot air flow to the suction points,

or place intake vents connected to the central air conditioning system
directly next to the perforated console back panels
making the ducts descend vertically to the floor
where they would be connected to the pipes embedded in the floor,
avoiding possible noise from fans.