Dac: it's BIII+ivy output stage.
For dsp I'm using ti omap l138 lcdk with my own custom software.
External VDR
I am planning to buy one SMPS1200A400 and two NC400 modules. I preferred SMPS1200A400 because it reduces the costs and I am planning to buy one system more to bridge two NC400 modules in the future.
As far as I read from the comments, using SMPS1200 does not have disadvantage other than consuming 5w more for each NC400 module.
I am thinking if it is possible to build external VDR (like 18V) from a small transformer and cheap linear regulator. Datasheet says VDR must be connected to VDR and -HV pins and must be floating. While it should not be referenced to ground, I confused,can you suggest a simple schema?
I am planning to buy one SMPS1200A400 and two NC400 modules. I preferred SMPS1200A400 because it reduces the costs and I am planning to buy one system more to bridge two NC400 modules in the future.
As far as I read from the comments, using SMPS1200 does not have disadvantage other than consuming 5w more for each NC400 module.
I am thinking if it is possible to build external VDR (like 18V) from a small transformer and cheap linear regulator. Datasheet says VDR must be connected to VDR and -HV pins and must be floating. While it should not be referenced to ground, I confused,can you suggest a simple schema?
If you look at the SMPS1200 data sheet it states on page 4 under 6.2 General performance data 1200@400 that it has a regulated VDR set to 15.6V. You might need to close read for getting the right jumper config but it should be doable
If you look at the SMPS1200 data sheet it states on page 4 under 6.2 General performance data 1200@400 that it has a regulated VDR set to 15.6V. You might need to close read for getting the right jumper config but it should be doable
But as far as I know, NC400 runs the internal regulator which dissipates 5w more when the VDR voltage is lower than 16V. 1200@400's VDR is 15.6v, do you mean there is a way to increase it?
You got me there
. Forgot the 16V limit for internal VDR regulation on nc400. Pretty annoying design choice to choose 15.6V for the smps1200A400 considering its applicability for the nc400... I wonder whether 15.6V is close enough to bypass the internal VDR supply and its 5W heat dissipation.You got me there
I think no because everyone who uses SMPS1200 says each module draws 5w more power.
Isn't it possible to supply VDR with a linear regulator?
For simplicities sake its easier to just use an RCA/Phono to XLR cable, as you get the bonus of shielding the cable with a separate ground that doesn't carry any of the audio signal.
Remember that the NC400 has a floating differential input that connects to each RCA conductor in unbalanced configuration.
EDIT: Of course this is all in the documentation, even what to do if you must install RCA posts in the box.
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Remind us again, why would you want to use an extra linear regulator instead of supplying an unregulated voltage to the internal hypex regulator?
I agree.
The problem is that dave123 wants to have *both* at the same time - that gets a bit tricky. The RCA's need to be isolated from the chassis, and you need to switch both the "hot" and the "cold" connections - so 4 poles for a stereo setup. Yes, there are 2-way 4-pole switches, but they aren't as common as 2-pole ones.
SMPS1200@400's VDR is 15.6 V while NC400 needs 16V min so the module will dissipate 5W more and will get warmer. When we take 4 modules into account, 20w more heat will be generated in the enclosure. I thought I can use a small transformer and linear regulator as solution. Is it possible?
My question is "why do you need a linear regulator"? Hypex specifies an unregulated (but floating) supply.
May be not, I thought regulated supply is better as it should be cleaner.
What is your suggestion?
Not necessarily. A linear regulator is basically a constrictor, but with a finite response time. It might be too slow to react to quick transients, and might still pass HF, while restricting maximum current and possibly introducing noise of it's own.
I would just live with the additional power dissipation, but if you don't want to do that, I would use a floating, unregulated supply (small transformer, diode bridge and caps), as Hypex specifies.
Okay, I am not professional and doing this as hobby so please correct me if I am wrong:
If I use 2x7.5V transformer, rectify it with a bridge rectifier, use two caps to smooth + and - leads, I will have +/-10V. If I do not use ground, are the + and - leads together become floating single 20V?
If so, should I connect + lead to VDR (pin11) and - lead to -HV (pin7 or 8)?
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