Channel Strip projet SSL 9K/W492/CLX-VU

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EmptyMusicBox1

Well-known member
Joined
Dec 11, 2012
Messages
137
Location
FRANCE LYON


Hello

I'm just started a Channel Strip with a SSL 9K pre + EQ Neuman W492 + a CLX-VU compressor (dbx160) on a 1U

For the PSU i want to utilise a TRIAD 50VA 18v 2,78a

The SSL 9k PSU need 18vac ok (direct to the trans)

For the CLX need 18vac ok direct to the trans

And for the W492 need +15/-15v i can utilise the +15/-15v rail of the CLX ?


the way for the audio will  IN-->SSL9K --> Dbx ---> W492--> Sym--> out !

what do you Think about that ? its possible no ? i Hope !

Thanks


 
I'm not an expert as many DIYers here but it would be interesting to be able to switch comp and eq order. I usually eq after compression and compress after eq, depending on source.

Just my 2 cents
 
I forget what IC is used in the W492, but I ordered a version from Mouser that was rated to more the +-20V, and racked mine with my S800 EQ's in a big case.  If you used the same type, you could use +-18V for everything.
 
EmptyMusicBox1 said:


Hello

I'm just started a Channel Strip with a SSL 9K pre + EQ Neuman W492 + a CLX-VU compressor (dbx160) on a 1U

For the PSU i want to utilise a TRIAD 50VA 18v 2,78a
Overkill! You don't need more than 30VA. Even 15VA should be adequate, unless you have a lot of bulbs or intend to power several units. Remember that with power comes electromagnetic radiation.
The SSL 9k PSU need +18/-18v ok (direct to the trans)
For the CLX need +18/-18v ok direct to the trans
And for the W492 need +15/-15v i can utilise the +15/-15v rail of the CLX ?
As craig suggets, you can power everything from +/-18. that would be beneficial for the state-variable filters in the W492.
the way for the audio will  IN-->SSL9K --> Dbx ---> W492--> Sym--> out !
It's a matter of taste, but my default routing is preamp -> EQ -> comp. I would at least have an HPF before the comp.

When you write "+18/-18v ok (direct to the trans)", I assume you mean via rectifiers and smoothing caps? With very light loading, the xfmr 18Vac will provide close to 26Vdc after rectification. 
 
I think abbey meant the larger the transformer within an enclosure, the greater chance of EM spill.

I always  use oversize  transformers too but within a limit.
 
hi thank you for your reactions !

this is the Wire 1er step of schema for the AC/DC  (with the W492 in +15/ -15v)

i try to find info about a IC in +18 to the W492




for the Trans dim i read that on the CLX vu :


 
sahib said:
I think abbey meant the larger the transformer within an enclosure, the greater chance of EM spill.

I always  use oversize  transformers too but within a limit.
Yes, that's what I meant. In fact it's a complex subject that goes far beyond "the bigger then xfmr, the larger the stray field". In fact smaller xfmrs often operate at higher flux than larger ones, but I know "probabilistically" that a 50VA xfmr will have more stray field than a 30VA from the same manufacturer.
I tend as much as I can to use larger xfmrs operating at lower flux; these have to be custom-ordered.
 
"For their part, transformers have long been known for their ability to inject both radiated and conducted noise into a system. Rather than being confined to the transformer's core, the radiation can be a source of hum. The electromagnetic field around the transformer isn't omnidirectional in its coverage, but rather directional. This minimizes interference to other components in the enclosure by locating the transformer in such a way that the radiation won't affect sensitive components.

An alternative has been to move the transformer to a section of the enclosure far enough away from these components to make interference in significant. Still, another option is to design a transformer with reduced EMI in mind. This is accomplished by designing the transformer with reduced flux density, which involves increasing the number of turns on the transformer or increasing its core area.
In addition, electrostatic shields placed between the primary and secondary windings of the transformer can be effective in reducing EMI. This technique is most often applied in noise- sensitive applications such as airframes, where suppressing EMI sources encompasses the design of the entire aircraft.

A Faraday shield is a type of electrostatic primary-to-secondary shield that's commonly
employed in transformers. The shield is usually one turn of thin copper foil that encircles the core and is attached to system ground. It prevents high-frequency current from coupling into the secondary windings. When left unshielded, this high-frequency current will more than likely find its way into the
entire system by means of inter-winding capacitance. The weight added by a Faraday shield is typically negligible. In low-power applications, the need for the isolation provided by a Faraday shield can be fulfilled with a split-bobbin transformer.
In extreme cases, one of several types of magnetic shielding can be applied. The shielding usually consists of an enclosure that surrounds the transformer, captures stray flux (radiation), and sends it to a solid system ground. It can be supplemented by another outer magnetic shield. This technique often is quite effective, but it's also expensive because the interior enclosures are made from high-nickel magnetic alloys and the exterior shields from mild steel. Together, they add considerable weight and complexity to the design. However, when the highest level of EMI protection is required, the magnetic enclosure is the first choice. "

so you can use a bigger transformer to lower flux density for a fixed power demand and therefor lower EMI, but >

"One thing that obviously confuses many people is the idea of flux density within the transformer core. While this is covered in more detail in Section 2, it is important that this section's information is remembered at every stage of your reading through this article. For any power transformer, the maximum flux density in the core is obtained when the transformer is idle. I will reiterate this, as it is very important ...

For any power transformer, the maximum flux density is obtained when the transformer is idle.

The idea is counter-intuitive, it even verges on not making sense. Be that as it may, it's a fact, and missing it will ruin your understanding of transformers. At idle, the transformer back-EMF almost exactly cancels out the applied voltage. The small current that flows maintains the flux density at the maximum allowed value, and represents iron loss (see Section 2). As current is drawn from the secondary, the flux falls slightly, and allows more primary current to flow to provide the output current. "

so as you increase xfmr size, you have two things fighting each other, flux will go down with the increase in core size, but flux will go up as you get closer to an unloaded condition,

see also as mentioned in the first quoted article that there is also bad stuff getting into the circuit thru the windings, so transformer construction is also important in the way of Farady shields and external cans.
 
Ok i think the Triad 25VA 18v will be Good for the 3 parts Pre/EQ/ comp

I can use the OPA2604AP for the W492 ( WIDE SUPPLY RANGE: Vs +- 4.5 to 24v) i need just change the OPERATIONAL AMPLIFIER on the PCB ?

"abbey road d enfer" said good i change the audio way for preamp-->EQ--> comp

do you think i need a JLM AC/DC kit with 3 rails ? +48V +18 -18 for all the Unit ? i need to bypass the PSU on the PCB of the CLX ?

Thanks !




 
EmptyMusicBox1 said:
Ok i think the Triad 25VA 18v will be Good for the 3 parts Pre/EQ/ comp
Your selected transformer will have a part number to identify its corresponding datasheet. You probably want a center tapped 36V secondary (18-0-18V) transformer or a (18V+18V) dual secondary transformer with its secondary windings connected in series, this series junction being your needed center tap (just as shown on your 2nd.pic for transformer hookup and contrary to your 1st.pic audio cards hookup where the green wire needs to connect to this center tap).
 
Your selected transformer will have a part number to identify its corresponding datasheet. You more probably want a (18V+18V) dual secondary transformer with its secondary windings connected in series, this series junction being your needed center tap (just as shown on your pic) or a center tapped 36V secondary (18-0-18V) transformer.

Yeah i have use this model for the SB4000 (50VA

http://fr.mouser.com/ProductDetail/Triad-Magnetics/VPT36-1390/?qs=wkKrz7WmEgM2EIrgD3Tzhw==

it's the VPT36-1390 TRIAD Magnetics 25VA

http://fr.mouser.com/ProductDetail/Triad-Magnetics/VPT36-690/?qs=sGAEpiMZZMvwUzoUXIIvyTw34uqMHR%252bu6om6EaaqGJg%3d

i will use this model for the channel strip !
 
remote power supply.

standardize your power connector.

overbuild the p.s. give it a few (female) sockets to power the next build too.
 
remote power supply.

standardize your power connector.

overbuild the p.s. give it a few (female) sockets to power the next build too.

i can't use an extrenal PSU because i want use this (futur) unit for the Live on a Small 5u and i lack of space ...
 
EmptyMusicBox1 said:
I can use the OPA2604AP for the W492 ( WIDE SUPPLY RANGE: Vs +- 4.5 to 24v) i need just change the OPERATIONAL AMPLIFIER on the PCB ?

is there something wrong with a 5532? Just because it is pin compatible does not mean it will work  completely free of issues, you may get oscillations or other issues.  AS mentioned before your +/- 18VAC you want to run the units at is perfectly fine for a 5532
 
pucho812 said:
EmptyMusicBox1 said:
I can use the OPA2604AP for the W492 ( WIDE SUPPLY RANGE: Vs +- 4.5 to 24v) i need just change the OPERATIONAL AMPLIFIER on the PCB ?

is there something wrong with a 5532? Just because it is pin compatible does not mean it will work  completely free of issues, you may get oscillations or other issues.  AS mentioned before your +/- 18VAC you want to run the units at is perfectly fine for a 5532

on the datasheet of the N5532 i read +-15v VCC

http://www.ti.com/lit/ds/symlink/ne5532.pdf



 
CJ said:
...............
An alternative has been to move the transformer to a section of the enclosure far enough away from these components to make interference in significant................

A good lesson can be learned by studying hi-fi or broadcast equipment. Japs (Sony, Panasonic etc.) have been masters of this. Often the transformer is surrounded by the electronics yet the performance requirements are met.
 
abbey road d enfer said:
Page 2 says:
ABSOLUTE MAXIMUM RATINGS(1)
over operating free-air temperature range (unless otherwise noted)
VCC+ 22 V
VCC Supply voltage(2)
VCC– –22 V

ok ! i can use the N5532 of the original BOM of the W492 with a +18v voltage ! thanks !
 
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