8 Channel, 3U NEVE 1073 completed

mrtrev said:

Hi everyone, I'm new to the forum! Just ordered 4 boards from Martin & I can't wait to get my build going Loved seeing all your pics about your builds, awesome stuff you've all inspired me to give it a go!

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Good for you man. Cheers and welcome!

Thanks for the welcome guys ;D I just hope I can do a half decent job of it, I'm good with a soldering iron but not so good at metalwork. I can even screw up drilling a pilot hole lol I must thank Martin too, very quick response to my email inquiry.

I'm looking forward to receiving the boards and getting started. I'm looking at building a 2U unit with 2 boards and an internal PSU, with PPM meters (would a tap from point B be good for this?). This box will hopefully go into my voice over studio, as that's what I do for a living. The other 2 units will be going into a Ham Radio transceiver set-up! Don't laugh lol

Any chance someone has a quick solution for US source of 2A PT to power 4 modules?
Can I still use the ACDC with the increased draw for 4 channels?

Cheers!

Check Antek for a toroid..

http://www.antekinc.com/details.php?p=33 
2x25, 50VA

Most people do it 1 psu for every 2 channels. You could, I suppose, get the 5 rail JLM, and use one positive rail for each 2 channels.  they are running in parallel off the bridge, so it's like 2 positive PSUs.  Would need to get different rectifier diodes that can handle the amperage as well, I think 1N400x are 1A max or thereabouts, but mouser/digikey are full of stuff that'll work.

I have open a v*i*n*t*e*c*h  power supply recently because i plan to power my 1290s with it,, and what i find inside was this http://ca.mouser.com/ProductDetail/International-Power/IHB24-12/?qs=sGAEpiMZZMu0oxGuRuNKH8MNxSrv1EW6Mz7QmyNtuSw%3d and this http://ca.mouser.com/ProductDetail/International-Power/IHB48-05/?qs=sGAEpiMZZMu0oxGuRuNKH8MNxSrv1EW6zs1mSMsOndg%3d  i dont know if they add some additional filtration in their preamp but in their psu, there was nothing more than those two unit. Seems like a very affordable solution to me. And they say on their website that it can power up to four x73 (1073) so it should be enough for four 1290 maybe more. i could post some pics of the inside if you guys want some.

Hubert

I am toying with making knobs . Have you found a place to get the ones you want ? Best  D

YLab said:

I have open a v*i*n*t*e*c*h  power supply recently because i plan to power my 1290s with it,, and what i find inside was this http://ca.mouser.com/ProductDetail/International-Power/IHB24-12/?qs=sGAEpiMZZMu0oxGuRuNKH8MNxSrv1EW6Mz7QmyNtuSw%3d and this http://ca.mouser.com/ProductDetail/International-Power/IHB48-05/?qs=sGAEpiMZZMu0oxGuRuNKH8MNxSrv1EW6zs1mSMsOndg%3d  i dont know if they add some additional filtration in their preamp but in their psu, there was nothing more than those two unit. Seems like a very affordable solution to me. And they say on their website that it can power up to four x73 (1073) so it should be enough for four 1290 maybe more. i could post some pics of the inside if you guys want some.

Hubert

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Pretty standard setup Id imagine too just 110AC in 24V/0VDC out.
Martin suggests 5mA per channel (I like the overbuild philosophy) so maybe:
http://ca.mouser.com/ProductDetail/International-Power/IHC24-24/?qs=0xCm9DOQnC6ncDRyEaAHUw%3d%3d
for 4 channels?

Def pics would be great!

Looks like maybe a good solution? Def wind up a bit more beefy than the JLM supplies.

Yes,, good idea for only 60$..

Image from the inside of the psu...pretty straightforward. left 48v, right 24v

You do realize that Rupert Neve (and now AMS-neve) spec the 1073, etc at 110mA per channel? That is a preamp and EQ which could, potentially, require more current. Can't really go wrong with an overdone PSU, but isn't 500mA (4x required current) per channel a bit wasteful? 

Maybe I'm reading specs wrong here but it seems, AMS-neve's 5U racks are rated at 0.8A, a bit less than a single JLM psu, and that's for 8 channels... How'd we go from 110mA to 500mA?

http://www.ams-neve.com/Sites/8/Files/Documents/Outboard/1073_1084_User_Manual_Issue5.pdf

mitsos said:

You do realize that Rupert Neve (and now AMS-neve) spec the 1073, etc at 110mA per channel? That is a preamp and EQ which could, potentially, require more current. Can't really go wrong with an overdone PSU, but isn't 500mA (4x required current) per channel a bit wasteful? 

Maybe I'm reading specs wrong here but it seems, AMS-neve's 5U racks are rated at 0.8A, a bit less than a single JLM psu, and that's for 8 channels... How'd we go from 110mA to 500mA?

http://www.ams-neve.com/Sites/8/Files/Documents/Outboard/1073_1084_User_Manual_Issue5.pdf

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Very good point.
I'm just going with Martin's philosophy and suggestion as I seem to recall reading somewhere that he suggests 500ma a channel
for the rugid overbuild.
Now that you lay it out, it does seem somewhat excessive...

When the 1073/1290 channel powers on, it draws a big chunk of current, then stabablizes down to 80-100mA. The rating is spec'd to properly handle this power on 'draw' i believe.

madriaanse said:

Speaking of the trim fader; I deliberately left it out because I really don't like what a trimpot does to the sound??? Sounds grainy/"slightly distorted" or something. Anyone else notice this on their Neves?

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Maybe it was the brand of trimmer you used Martin? What trimmer did you try? I've put drill holes on my frontpanel for the P&G RF11 if they ever need to be added.

stitch-o said:

I'm just going with Martin's philosophy and suggestion as I seem to recall reading somewhere that he suggests 500ma a channel
for the rugid overbuild.
Now that you lay it out, it does seem somewhat excessive...

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I don't like to go against anyone's beliefs or philosophies, there is some validity to the idea of not running your PSU at maximum all the time. Taking into consideration that some toroids and other components may not be true to spec (meaning they are over rated), and maybe that's why some people decide to overbuild stuff. But if you use decent quality components I can't see it being a problem. Then again, I could be wrong.

desol said:

When the 1073/1290 channel powers on, it draws a big chunk of current, then stabablizes down to 80-100mA. The rating is spec'd to properly handle this power on 'draw' i believe.

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I saw that written somewhere as well... Wouldn~t this imply that the AMS 8 channel rack would not be able to handle this inrush of current at startup if it's only 0.8A?  Also, there would be a problem for anyone building a 10 or 11 space GDIY rack full of neve pres (51X style, whenever they become available, I'm sure people are already designing the PCBs), since the PSU is using 3A regulators, no? 

kinda thinking out loud I guess...

Well, Peter Purpose has already designed his EQ's to power on delay, so they wait for
the power supply to stabilize. So...either over-spec the power supply for this in-rush or
design the modules to delay on a bit. I'm guessing.. Excess current i think would be also needed
if the pre's are driving something after and for headroom.

The AMS thingy may have something else going on entirely. Don't know.

I think the delay in Peter purpose's EQ (haven't checked that thread these days, but I think it's Dan Kennedy's circuit) is not for the 24V rail, but for the DC-to-DC converter on the 16V rails (it will be compatible with either the 51X or regular 16V racks). It's the converter that sucks a lot of juice at startup. 

I've been trying to find an answer to this for weeks, because there are those (like bae, vintageking, and others who rack and/or remake neve stuff) who use the terms "overspec'ed PSU for higher quality audio," while at the same time there are quite as many big mfgs who don't do this.  I found a couple of interesting threads here and there, but nothing concrete, and seeing that Vintech uses 1.2 Amps for 4 channels and AMS themselves use a smaller one for 8 channels (a bit unbelievable, this one, but it's written in the manual), doesn't it make you wonder how it's possible that perhaps these guys (who are paying big $$ for engineering) are using so much less?

mitsos said:

I saw that written somewhere as well... Wouldn~t this imply that the AMS 8 channel rack would not be able to handle this inrush of current at startup if it's only 0.8A?

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Hence the 500ma per channel? What might the current spike be on powerup?

I don't know the answer. I've tried posting in this thread 10 times and this computer keeps erasin my posts.... so maybe it's a sign. I just think it's curious that there are so many mfgs making this circuit, and some use large PSUs while others use smaller ones, and the ones who use the large ones overtly advertise it as something that makes the audio of their product better.

There is the argument of running your PSU at less than capacity in the hope that it will last longer, but I don't think that is the case here, otherwise BAE (and others) wouldn't mention it. So.. anyone?

Current inrush, I guess could be measured with an Ammeter. I'll do it when I get a chance. Not sure if it's true or not, since class A is supposed to be constant currrent, no? So unless you have tons of capacitance in the circuit this shouldn't happen, I think.

But anyway, this is getting a bit academic.  I do plan to continue searching this out, but you mentioned you were making these for some studio I think, so sorry to get your attention off that.. get whatever works and be done with it. 

This may be completely irrelevant (if so ignore lol) but how about a bit of conditioning on the mains input? Perhaps something like this http://www.spezial.com/commercio/dateien/produktbeitraege/FN_9263.pdf IEC inlet with filtering and current inrush protection.

Just wanted to say I just wired up 2 of 4 channels of the EZ 1290 and after a brief problem with a shorting power cable they are sounding absolutely wonderful! Big warm and round, my guitar has never sounded so good. I'm so happy!!

This was my first build, and I'd be happy to post some pics and sound samples if people want to see and hear.

Thanks Martin and thanks to all the people who post here.

Take care everyone,

John.

Pictures are always fun!

Jake