Will this power supply work with my console?

witchfeet · 20th January 2012

Hi there. I have a Soundcraft Spirit Studio 24 channel. I'm running the stock CPS150 PSU right now. I was wondering if the "Soundcraft Large Console PSU" would be able to work with my board either stock or with mods? Would this be an upgrade sonically?

Ike Zimbel · 20th January 2012

Need more specifics to answer your question. A model number of the large supply would be ideal.
Best,
Ike

witchfeet · 20th January 2012

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Quote:

Originally Posted by Ike Zimbel

Need more specifics to answer your question. A model number of the large supply would be ideal.
Best,
Ike

Thanks for the reply. Unfortunately it doesn't seem to have an actual model number. It's just called "Soundcraft Large Console PSU".

Ike Zimbel · 20th January 2012

Gawd I love it when I get cranky and then it turns out I'm wrong. I did find, in my Soundcraft PSU folder, a folder called "Large-Med-Small" and, sure enough, that's what they're called. To answer your question, if it supplies the voltages that you need (I can't find my Spirit docs, but I think it's just +/-17 and 48v), then you should be able to use those and ignore the rest. And, yes, if the supply puts out more current, you should be able to hear that.
Cheers,
Ike

Matt Syson · 20th January 2012

Hi Ike
Shame on you for running into this 'more current is best' BS. For this to be true you have to defy Ohms law in an obscure way. The current capability of a power supply is a separate aspect to it's output impedance, which MIGHT affect performance depending on how bad the desk design is.
Even a humble LM317 when wired correctly can manage an output impedance of a few tens of milliohms, about the same as a 20 Amp monster supply. Unless you actually DRAW more than the supply is capable of the actual rating is (for this discussion) immaterial.
The resistance of the cable from supply to desk is usually more significant.
Matt S

Ike Zimbel · 21st January 2012

Hi Matt,
I know that a bigger supply is not going to PUSH more current into a desk, but I do think that having more current AVAILABLE for the desk to draw WHEN REQUIRED could do something nice for transient response. It would be nice to think that every desk was sold with a supply that was perfectly matched to its needs but the realities of manufacturing, sales etc (which I know you are more familiar with than I) sometimes dictate otherwise.
Best,
Ike

Matt Syson · 22nd January 2012

Hi
This is diverting from the original question but output stages using for example a 5532/4 or most other similar chips that are happy driving 600 Ohms, have current limit set internally at about 30 - 40mA. It would be possible to argue that if you had say 24 outputs running into current limit (approaching a short circuit on all 24 outputs) that you desk would require say 1 Amp more than it's 'no signal' condition.
The remainder of the circuitry inside the desk is not driven with anything like this current requirement so an additional say 10 percent above no signal conditions is needed. I did test this out a year or so back and it is realistic. Running all channels close to clipping (with a continuous sinewave) is pretty horrendous in terms of sound so is an unlikely scenario.
Transient response demands current from the LOCAL power rail capacitors and if the desk is so badly designed that it requires a super low impedance power supply unit the result of all the voltage drops on the internal and external wiring would render the outputs of such a desk to be practically 'mono' as crosstalk would be at ridiculously high levels.
Massive current 'peaks' are a feature of class B (or similar) power amplifiers driving loudspeakers where the no signal current is measured in the hundreds of milliamps and the current required at full signal is many Amperes.
A mixing desk takes a high 'quiescent' current with occasional peaks in the order of 20 percent increase (if that).
Matt S

Jim Williams · 22nd January 2012

It should work fine. The problem is they have large 10 pin Hirosi connectors and you will need to install one on the console to accept that rather large cable.

The Large Console Power Supply was one of their best, it does have a fan. It has + - 7.5 volts for logic, 48 phantom, + - 17 audio and + 24 v for meters.

It's best to open and clean out the dust in the tunnel. Check and replace the fan if worn out. Re-install filter foam to keep dust out. I install 18,000 uf mains caps in place of the stock 4700 uf's, that pulls down ripple well and tightens up the low end.

These were the stock supplies for the TS-24 and 8000 consoles.

Matt Syson · 22nd January 2012

Hi
I can appreciate that increasing the filter caps from 4,700 to 18,000 would reduce ripple but would you mind explaining how doing so 'tightens the bottom end' since these caps are on the 'wrong' side of the regulator and also at the 'far end' of the power supply cable.
Are you actually referring to capacitors 'after' the regulator which may have a small influence depending on the output impedance of the supply as a whole?
I presume otherwise the laws of physics are a little different in the USA?
Matt S

Matt Syson · 22nd January 2012

Hi
Just tried a chunk of mixer and it's no signal current was 33.4mA.
When passing signal at +22dBu output, with no load the current increased by 0.5mA (going through 4 ICs).
Putting a 560 Ohm load on the output increased the current to 39.8mA aproximately 6mA increase due to driving a load hard. Not a massive increase really.
While it is not a test that is quite related to a full desk, since this was only one module but when outputting +22dBu into the 560 Ohms, the 'disturbance' AT THE SUPPLY, which is a pair of LM317 /337 regulators thrown together 25 years ago, measured at -75dBu, 95dB lower than the signal. Incidentally the board I am looking at has NO power rail caps (part of why I m looking at it) and adding some 220uF at the board removed all the 'disturbance' at the supply., leaving only 'noise' at about 26uVolts.
Sorry this diversion is well away from whether the PSU is suitable (which it will be, if rather excessive) but 'beefing up the LF' is BS.
Matt S

Jim Williams · 24th January 2012

This is what the users say. I'm not one to tell them they are wrong in what they hear. Nearly everyone of them comments on the more powerful low end.

Ripple is very low. I also use very large caps on the outside of all those regulators (which are discrete in the LCPS) as well as selected higher beta/lower noise discretes. Usually I get about 1 mv noise on those rails, pretty good. The local large el psu bypass caps on the modules remove anything picked up afterwards. I use very low impedance caps, like Panasonic FR series, those are far superior to common el caps. A Whisper XL fan is lower noise too.

Another adavantage is those caps should last about 40~50 years, I won't need to do that again. I'm not going to argue physics with those that hear differences, that's an excersize reserved for university instructors.

Matt Syson · 24th January 2012

Hi
Ah, the power of the 'depleted wallet' effect.
Matt S

witchfeet · 25th January 2012

Thanks for all the replies. Sorry I started an argument!

If it is an upgrade sonically or not, that seems to be an area of debate. But, I think getting the supply merely for the fact I can use it, and have the stock power supply as a backup probably makes it a worthy purchase.

Thanks again everyone!

20th January 2012	#1
witchfeet Gear maniac Joined: Jun 2010 Location: Chicago Posts: 196 Thread Starter	Will this power supply work with my console? Hi there. I have a Soundcraft Spirit Studio 24 channel. I'm running the stock CPS150 PSU right now. I was wondering if the "Soundcraft Large Console PSU" would be able to work with my board either stock or with mods? Would this be an upgrade sonically?

20th January 2012	#2
Ike Zimbel Gear addict Joined: Oct 2006 Location: Toronto, Canada Posts: 455	Need more specifics to answer your question. A model number of the large supply would be ideal. Best, Ike __________________ -- Ike Zimbel, Zimbel Audio Productions Ltd. Toronto 416-720-0887 "Studio House Calls". Authorized Warranty service for Allen & Heath, Clear-Com, Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to analog audio equipment including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft and more. Ask about our RF frequency co-ordination services! www.zimbelaudio.com

20th January 2012	#5
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	Hi Ike Shame on you for running into this 'more current is best' BS. For this to be true you have to defy Ohms law in an obscure way. The current capability of a power supply is a separate aspect to it's output impedance, which MIGHT affect performance depending on how bad the desk design is. Even a humble LM317 when wired correctly can manage an output impedance of a few tens of milliohms, about the same as a 20 Amp monster supply. Unless you actually DRAW more than the supply is capable of the actual rating is (for this discussion) immaterial. The resistance of the cable from supply to desk is usually more significant. Matt S __________________ Matt S www.mseaudio.co.uk

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21st January 2012	#6
Ike Zimbel Gear addict Joined: Oct 2006 Location: Toronto, Canada Posts: 455	Hi Matt, I know that a bigger supply is not going to PUSH more current into a desk, but I do think that having more current AVAILABLE for the desk to draw WHEN REQUIRED could do something nice for transient response. It would be nice to think that every desk was sold with a supply that was perfectly matched to its needs but the realities of manufacturing, sales etc (which I know you are more familiar with than I) sometimes dictate otherwise. Best, Ike

22nd January 2012	#7
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	Hi This is diverting from the original question but output stages using for example a 5532/4 or most other similar chips that are happy driving 600 Ohms, have current limit set internally at about 30 - 40mA. It would be possible to argue that if you had say 24 outputs running into current limit (approaching a short circuit on all 24 outputs) that you desk would require say 1 Amp more than it's 'no signal' condition. The remainder of the circuitry inside the desk is not driven with anything like this current requirement so an additional say 10 percent above no signal conditions is needed. I did test this out a year or so back and it is realistic. Running all channels close to clipping (with a continuous sinewave) is pretty horrendous in terms of sound so is an unlikely scenario. Transient response demands current from the LOCAL power rail capacitors and if the desk is so badly designed that it requires a super low impedance power supply unit the result of all the voltage drops on the internal and external wiring would render the outputs of such a desk to be practically 'mono' as crosstalk would be at ridiculously high levels. Massive current 'peaks' are a feature of class B (or similar) power amplifiers driving loudspeakers where the no signal current is measured in the hundreds of milliamps and the current required at full signal is many Amperes. A mixing desk takes a high 'quiescent' current with occasional peaks in the order of 20 percent increase (if that). Matt S

22nd January 2012	#8
Jim Williams Voiding warranties Joined: Feb 2004 Location: beautiful Carlsbad, CA Posts: 10,069	It should work fine. The problem is they have large 10 pin Hirosi connectors and you will need to install one on the console to accept that rather large cable. The Large Console Power Supply was one of their best, it does have a fan. It has + - 7.5 volts for logic, 48 phantom, + - 17 audio and + 24 v for meters. It's best to open and clean out the dust in the tunnel. Check and replace the fan if worn out. Re-install filter foam to keep dust out. I install 18,000 uf mains caps in place of the stock 4700 uf's, that pulls down ripple well and tightens up the low end. These were the stock supplies for the TS-24 and 8000 consoles.

24th January 2012	#11
Jim Williams Voiding warranties Joined: Feb 2004 Location: beautiful Carlsbad, CA Posts: 10,069	This is what the users say. I'm not one to tell them they are wrong in what they hear. Nearly everyone of them comments on the more powerful low end. Ripple is very low. I also use very large caps on the outside of all those regulators (which are discrete in the LCPS) as well as selected higher beta/lower noise discretes. Usually I get about 1 mv noise on those rails, pretty good. The local large el psu bypass caps on the modules remove anything picked up afterwards. I use very low impedance caps, like Panasonic FR series, those are far superior to common el caps. A Whisper XL fan is lower noise too. Another adavantage is those caps should last about 40~50 years, I won't need to do that again. I'm not going to argue physics with those that hear differences, that's an excersize reserved for university instructors.

25th January 2012	#13
witchfeet Gear maniac Joined: Jun 2010 Location: Chicago Posts: 196 Thread Starter	Thanks for all the replies. Sorry I started an argument! If it is an upgrade sonically or not, that seems to be an area of debate. But, I think getting the supply merely for the fact I can use it, and have the stock power supply as a backup probably makes it a worthy purchase. Thanks again everyone!