Hypex DSP module(s)

I had a few questions regarding grounding of UCD AMps. I suppose it has nothing to do with UCD AMps per se, more about electronics theory perhaps.

1. I can see an AC voltage of 89V between the UCD 180 OEM heatsink and IEC earth (ie, when chassis is not connected to IEC earth). A similar voltage exists between UCD 400 HG heatsink and IEC earth as well. Is this abnormal?

2. Are we supposed to connect the IEC earth pin to chassis so that such voltages become zero?

3. Does the DLCP have a log that one can analyze to see why it gets frozen (ie, volume keys don't work)
 
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If I try to do that, I get strange behaviours from DLCP.
Pls see pic.
 

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The following Q has probably been discussed before, but I couldn't find a specific answer.

A UCD OEM connected to a Hypex SMPS XXX series can handle dc error easily by directly connecting, pin 33 to SMPS:J3:4. Nothing else is needed?

By directly connecting, I mean a piece of wire connecting the 2 pins.

This is because, the OEM has an internal open collector on pin 33?

Wanted to double check this.

Thanks
 
Notes on how to power on DLCP, DLCP SMS, UCD, SMPS400XXX correctly

I thought I should post some observations about the power up sequence of a kit consisting of DLCP SMPS, DLCP, UCD, SMPS400XXX.
Pls correct if I figured something incorrectly.

Requirements:
1. When mains-power is switched on, SMPS must get power and be ready in stand-by mode.
1a. DLCP must not turn on. Why? Sometimes, there is a huge inrush, and my ELCB blows.
1b. Ideally I would like to give power to the SMPS in a sequence, one after the other.

2. Now, once SMPS(s) are in standby, when a stand-by-push-button (or remote power button is clicked) is invoked, DLCP must turn on.
3. When DLCP is ready, it should trigger the smps(s), which should switch on the amps.
4. When the stand-by-push-button (or remote stand-by) is off, the smps should be in power saving mode (ie stand by mode).
5. No pop on start/ stop .
6. No pop on loss of power

Once the system is ON, requirements 2 to 6 are easily solved.

How?
  • Use DLCP amp on (J16:2) and connect that to the SMPS(s) @ J5:2.
    • Caution: the amp_on voltage from J1 is at a different level from amp_on on J16:2. More than 2 volts difference.
    • The other alternative - of giving amp-on from DLCP to amps directly is not a good idea. For egs, it can't solve for loud pop during power-loss situations.
  • Use auto-amp-enable line from the SMPS(s) to the respective amps.
  • Use smps-standby from J16:1 of DLCP and connect that to J5:1 of each SMPS.


However, this does not solve for requirement 1 - namely prevent entire system from being on when mains power is ON.

I can't figure a good way to solve this without building additional circuitry.

Notes
  • On DLCP SMPS: When SMPS DLCP is powered on, since J2 (on/off) is coming in from DLCP, J2:1 is low, because DLCP is off. So SMPS DLCP Vaux is ON by default, and therefore DLCP also gets switched ON.
  • The moment DLCP is ON, the DLCP:J16:1 (smps_standby) pin is low. So, even if this pin is connected to SMPS(s), they turn on automatically (ie power is available on their J3 terminals).
  • This means, there is no way to stop DLCP and AMPS from being fully ON, when mains power is ON. I think we can live with this.

I am curious to know what is the simplest thing to do, to power the SMPS-es one after the other and finally the DLCP SMPS, to solve inrush current problem. (Any guidance will be useful; I am a newbie).

Additional notes:
One way to solve requirement 1 is: cut the DLCP SMPS to DLCP ribbon cable, pin1 ribbon, and insert a "high voltage" on pin 1, using some other circuit.
This should trigger DLCP SMPS to have V-aux as low, which means the DLCP is off during mains power ON.

However, this is not useful, because then smps_stand_by from DLCP is low (since DLCP is off), which means the SMPS(s) get switched on fully. So, #1.a is not met.

If you don't use DLCP SMPS (and use SMPS for powering DLCP), when you hit stand-by on remote, it does not power off the DLCP completely.

Additional insights welcome.
 
HYPEX SYSTEM BUILDS

I believe this is not OT, as this attempts to address some of the problems faced by Hypex system integraters.

For quite some time I have been following system builds using Hypex modules, which are supposed to be "fool-proof". Perhaps it is the lack of a proper number of that kind in the DIY space is what is causing a lot of heartaches for the enthusiastic system builder! I have also noticed many questions in the threads for which conflicting answers have been given. Mr Putzeys (formerly of Hypex), no doubt, is a brilliant designer and his team is likely to be a good match for his genius. But as is often the case with designers and engineers, they assume a lot, particularly about the awareness of the average DIY enthusiast of the "small print stuff", which they, in their familiarity, often leave unsaid. From that angle, the Hypex documents and manuals at times offer perplexing choices to the builder, particularly when it comes to the usage of digital control signals. Even the labelling of module pins at times are confusing. Here I make the assumption that most of 'us' are like me, in that it is largely our enthusiasm, our readiness to learn and our willingness to be led by knowledgeable peers is our propellant! (My apologies to the many "pro-level" souls in our space who remain our chief inspiration!)

Hypex technical documents are second to none and they provide copious data to the builder. However, they have grievously fallen short in providing more examples of typical combinations of modules and more detailed explanations of how similar results could be achieved in slightly different ways, and why a particular method might be better in a particular scenario. We shall in these posts attempt to fill this lacuna.

I have based my recommendations on available Hypex data and the advice of experts in my personal circle. (My deepest gratitude to them for their patience in tolerating my foolish questions, and producing practical answers and solutions!) Also, let me take an "anticipatory bail" from the Inquisitors (who are omnipresent on every forum) by admitting that I am not an engineer (nor a digital systems expert) by training. Consequently any omissions are attributable to my foolishness alone. But kindly note that corrections/guidance will surely be admitted/accepted gladly!

Let us take a look at a typical 'complex' system consisting of a DLCP and say, six amplifier modules and their SMPSs, which should make up a "state-of-the-art" multi-way system. There are easily a dozen caveats, minor and major, that the builder should be wary of if s/he is to avoid many pitfalls and SNAFUs.

#1: The first caveat is, Hypex SMPSs do not need a soft start module. Their design takes care of a 'soft start' that happens in less than a couple of seconds. It is only when you use a transformer PSU with huge capacitor banks (which offer a virtual short circuit at switch-on) that you need a soft-start circuit.

A satisfactory 'soft start' can be fashioned from an NTC resistor of adequate power rating and a relay circuit that shorts it out after a small delay. The simplest soft start can be implemented with nothing fancier than a three-way switch in the AC mains line and a power resistor in series with the transformer primary that offers "off-standby/softstart-fully on" positions. KISS!

#2: The second is likely to be the 'states of on and off'. We are accustomed to throwing (or pushing!) a fancy switch to bring to life our esoteric builds. Well and good. But in equipment where micro-controllers are used to implement various tasks, one needs to keep in mind a few more things. Throwing the "main switch" only feeds power to the SMPS; then the micro-controller comes to life and sets about a predetermined sequence of tasks, which include self testing, checking various presets etc and then triggering various 'peripherals'. Also, when the system, under uP control, goes into 'standby mode', it might look as good as 'dead' to all appearances; but the uP has to remain ticking, and watch for the 'on' command from the remote control.

The DLCP module is the 'nerve centre' and the intelligent controller in the system. Luckily for us Hypex provide a matching small SMPS for it. Of course, we could power it in a few other ways (to be looked at later), but then meeting the basic essential requirements would be the only insurance in having a properly working system.

The dedicated DLCP SMPS provides V+/- voltages for the DLCP circuitry and also a standby supply (+ 8V typ). Pin 1 of the ribbon interconnect feeds the 'standby' control from the DLCP uP to the SMPS, which puts it into power saving standby mode, when V+/- rails are shutdown, but keeps the Standby rail on. Some DLCP SMPS faults are known to shut down this too, leading to indeterminate states. So put your voltmeter between the DLCP J17#1 (internally connected to J4#6) and J16#5(Ground) and verify that the standby supply rail for the uP is 'live' in the remote-selected 'standby' mode.

When the system goes to 'sleep', the total power consumption drops to less than 150 mW, far below the mandated 0.5 W. Do remember that in the sleep mode, the uP is ticking and a software 'daemon' watches for the 'on' command from the remote, when the V+/- will be switched on, and commands will be sent sequentially for switching on the other SMPSs and amp modules.
Do NOT cut J4#1, unless you are a brain surgeon! (Later we shall look at other options of powering the DLCP and still maintaining full functionality; kindly be patient with a senior citizen!)

#3: The third noteworthy point is regarding digital control signals like SMPS-on, Amp-on etc. The DLCP provides pins for such functionality and mostly the designated pin, by default showing a high voltage (HI), switches to a low voltage (LO) to implement this.

In the interests of an orderly and sequential switch-on, and avoidance of switch-on audio artifacts, the best way AFAIK is to leave the task of switching on the amp to its respective SMPS. (This simplifies system inter-wiring and makes fault-finding easier.) The DLCP will instruct the SMPS concerned, and it proceeds to switch on the amp module connected to it. A most satisfactory arrangement, IMHO. Every Hypex SMPS has an 'auto amp-on' pin that could be connected to the amp module, and an SMPS-on pin that takes the amp-on command signal (LO) from the DLCP.

Kindly note that as soon as the DLCP uP is switched on, is stable and in control, it issues 'amp on' (LO) on its control pins-- J16#2, J10 to J15#3. Since J10 to J15 provide balanced audio feeds to the individual amp modules, it is easy to use the individual Pin#3 'amp on' signals. However, do NOT connect it directly to the amp modules, but connect to the relevant SMPS-on pin, to reap the advantages mentioned in the previous paragraph.

As an example, with Hypex 400HG amps fed by SMPS400A400, connect SMPS J3#5 (auto amp on) to 400HG J1#1. Assume that this channel is fed from DLCP J10, the audio signals going to the other pins of 400HG J1. Cut the wire coming from DLCP J10#3 (amp on LO), extend it and connect that to SMPS400A J5#1 (SMPS on)-- I am assuming that you are using a ready-made Hypex connector here.

The other channels may be fed from DLCP J11 onwards in a similar manner, with each 'amp on' command wire being cut and extended to feed the respective SMPS-on pin.

#4: The next point likely to confuse the unwary system builder (and perhaps result in bald patches on the head!) is the concept of speaker protection in the event of amp malfunction. Hypex manuals mention both DC ERROR and DC DETECT. Woe to the poor DIY soul who assumes that both achieve the same purpose and so must be similar. Sadly, a big NO.

Hypex warn that DC ERROR functionality should ONLY be used with their OEM range of amplifiers. (I am told that there are quite a few who provide OEM modules to the DIY builder, and when a system is configured with a mix of OEM and DIY modules, most of the time nothing happens and silence greets the builder. Since this does not concern the average builder using DIY Hypex modules, we shall postpone looking at it in detail to a later post.)

DC DETECT works with every Hypex DIY module (or a generic amplifier driven by the Hypex SMPS). From our previous example the 400HG, a DC sense wire is taken from the + terminal ('hot') of the loudspeaker connector and fed to its SMPS J6 #1 or #2. (the SMPS 400A provides dual sense pins; any one may be used.) The moment a DC voltage >12 V appears on the speaker pin, the SMPS shuts down.

I trust this much is essential background information before embarking on the task of cooking up a typical system, which needs more drawings than words. Thank you for your patience and do forgive me for pontificating on very basic stuff. The advantage that I have as a relatively ignorant DIY enthusiast is that I bring no convictions of my own-- I am willing to be led by published documents and expert advice, and I am sharing my thoughts hoping it might bring some clarity.

Serendipitous discoveries are all too common in the DIY space. But publishing baseless convictions and accidental results as gospel truths (remember, just three consecutive lucky accidents are all it takes to convert you into an 'expert'!), and proposing obviously foolish experiments that lead nowhere is a disservice-- AFAIK.

If the above pointers have served to clear the air regarding some practical approaches relating to Hypex modules, I shall be most happy. I hope to post some typical configuration drawings and offer a few tips to check up your final assembly before pushing that fancy power switch!

Best regards, as always,
--UKP