Hypex NC252MP Overheating?

[antennaguru]

Apparently those pops can damage the amplifier if the voltage spike is of sufficiently high voltage and duration. See question 7 here:https://www.hypex.nl/faq/ (The question refers to a tube pre-amp. My preamp is a solid state SHD unit, so not the same conditions. But the point remains that it is better to enable the power amp after the pre-amp has stabilized.)

It is normal to turn on the power amplifier last during the turn-on sequence, and to turn off the power amplifier first during the turn-off sequence. This is to protect the power amplifier and the speakers from warm up thumps from the preamp and sources.

The Ghent casework seems to have very small holes in the lid, to allow heat to convect up and put of the case. I happen to have used one of their cases with similarly small holes a few years ago for housing an IcePower module, and I enlarged most of the lid holes in a pattern on my drill press because they looked too small too me the way they came from Ghent. It's still working after several years.

 

[Buckeye Amps]

It is normal to turn on the power amplifier last during the turn-on sequence, and to turn off the power amplifier first during the turn-off sequence. This is to protect the power amplifier and the speakers from warm up thumps from the preamp and sources.

The Ghent casework seems to have very small holes in the lid, to allow heat to convect up and put of the case. I happen to have used one of their cases with similarly small holes a few years ago for housing an IcePower module, and I enlarged most of the lid holes in a pattern on my drill press because they looked too small too me the way they came from Ghent. It's still working after several years.

I never liked the small holes on the cases, either.
One of the latest NC502 Ghent cases I just received for a build did have more traditional slit cut outs on the lid. Maybe he is changing the design going forward.

 

[JRS]

Apparently those pops can damage the amplifier if the voltage spike is of sufficiently high voltage and duration. See question 7 here:https://www.hypex.nl/faq/ (The question refers to a tube pre-amp. My preamp is a solid state SHD unit, so not the same conditions. But the point remains that it is better to enable the power amp after the pre-amp has stabilized.)

That's just good practice, protects your speakers from turn on thump as well. I believe that the issue was over a speaker wire being pulled out--say you tripped over it, ripped it out from the speakers, but avoided a dead short. Why would that be harmful is a good question. Or maybe I missed something, if so please ignore.

 

[restorer-john]

So @restorer-john - is there anything that us mere mortals can do to extend the life? Would it be worth slathering certain components with non conductive heat sink compound?

The issue I highlighted, is the module design in that localized area. No amount of heatsink compound on the plate will help.

Once the board has flexed, it stays flexed and the pressure on the devices to maintain adequate thermal contact is reduced. The flexing of the PCB will place undue stress on any SMD components laying across the curve/flex- they may also fail in time due to cracking or solder joint failure. PbFree solder is hardly renowned for its flexibility.

The same mounting method is used around the output devices, but there are 5 screws in close proximity to the packages. There is less opportunity for the PCB to bend.

There's really nothing that you can do, the board needs a redesign with correct mounting methods for the devices in question. No PCB should be pressed into service (pun intended) as a device-to-heatsink clamp.

When in standby, those MOSFETs should not be running hot- the auxilliary supply standby switches on the main supply. The auxilliary supply shouldn't run hot. You can potentially prolong the life by unplugging the amplifier when not in use.

 

[Buckeye Amps]

Regarding standby: The Ghent cases do not have a dedicated Standby switch unfortunately. They can only be controlled by the main power On/Off switch. I can also confirm that leaving an module On (not in Standby but just On with no signal) produces a good amount of heat. Not excessive but more than one would like for not actually being used.

 

[peng]

Apparently those pops can damage the amplifier if the voltage spike is of sufficiently high voltage and duration. See question 7 here:https://www.hypex.nl/faq/ (The question refers to a tube pre-amp. My preamp is a solid state SHD unit, so not the same conditions. But the point remains that it is better to enable the power amp after the pre-amp has stabilized.)

As long as the amp is switched on last and off first, the pops don't seem to be an issue but I wouldn"t take a chance. For a few $, the standby switch is worth the effort. A fan is a must too, for longevity unless adequate heatsinks are used.

 

[KMO]

Datasheet seems to say that the idle power loss is typically 15.5W (8.5W for the SMPS and 3.5W per channel for the amps). Not insignificant, and going to keep it a bit warm. But shouldn't be as hot as the OP describes though.

Total standby power would be a fraction of a watt (the SMPS consumes 0.12W in standby, the amps would be powered down, and you'd add the consumption of the standby control circuitry).

 

[RickS]

As long as the amp is switched on last and off first, the pops don't seem to be an issue but I wouldn"t take a chance. For a few $, the standby switch is worth the effort. A fan is a must too, for longevity unless adequate heatsinks are used.

While agreeing it cannot hurt to be cautious, Hypex uses a Ghent case for the NC400 kit. It has no trigger or standby and little vent holes on top...

Would expect @restorer-john to be skeptical, but Hypex apparently thought the Ghent case could dissipate the heat of the NC400. Have not done the math for the MP series amps, but an NC252MP does not seem a major stretch from an NC400. If they have a defect, that is another issue, but have many Hypex amps and no sign any of them have heat issues. Almost all of them I have are in Ghent cases.

 

[peng]

While agreeing it cannot hurt to be cautious, Hypex uses a Ghent case for the NC400 kit. It has no trigger or standby and little vent holes on top...

Would expect @restorer-john to be skeptical, but Hypex apparently thought the Ghent case could dissipate the heat of the NC400. Have not done the math for the MP series amps, but an NC252MP does not seem a major stretch from an NC400. If they have a defect, that is another issue, but have many Hypex amps and no sign any of them have heat issues. Almost all of them I have are in Ghent cases.

Yes, to me it is not about overheating, but as I said, for longevity, and as you said, just being cautious. I only turn on the fan if I know I will be using it for longer than a couple hours.

My next Buckeye amp will be in his stock case that I don't think look as good but bigger if I remember right so that may help. I believe it also include a robust looking standby switch.

 

[maty]

It will also depend on the load, that is, the loudspeaker. What speakers do you use?

Sensitivity and ... minimum impedance?

Loudspeaker is the first thing to eliminate from the equation.

 

[Buckeye Amps]

Yes, to me it is not about overheating, but as I said, for longevity, and as you said, just being cautious. I only turn on the fan if I know I will be using it for longer than a couple hours.

My next Buckeye amp will be in his stock case that I don't think look as good but bigger if I remember right so that may help. I believe it also include a robust looking standby switch.

Standby switch and 12v trigger.

I have also started rolling out my cases that feature the entire inside bottom panel bare aluminum (not powder coated) to better help with grounding and heat transfer.

 

[peng]

It will also depend on the load, that is, the loudspeaker. What speakers do you use?

Sensitivity and ... minimum impedance?

Yep, again, better to be safe than sorry.

 

[RickS]

Yes, to me it is not about overheating, but as I said, for longevity, and as you said, just being cautious. I only turn on the fan if I know I will be using it for longer than a couple hours.

My next Buckeye amp will be in his stock case that I don't think look as good but bigger if I remember right so that may help. I believe it also include a robust looking standby switch.

I agree, I have added standby switches to some of mine. Rather than drill thru the thicker front faceplate, have put on the front underside.

 

[peng]

Standby switch and 12v trigger.

I have also started rolling out my cases that feature the entire inside bottom panel bare aluminum (not powder coated) to better help with grounding and heat transfer.

Really, I thought the trigger is an option. Now I am tempted to get another one that I don't need. It would be even more tempted if you could do the Purifi, or at least offer the NC500. Any chance for that?

 

[peng]

I agree, I have added standby switches to some of mine. Rather than drill thru the thicker front faceplate, have put on the front underside.

By the way, you were the reason I went with Buckeye's instead of a 2nd Purifi so thank you for that. I am very happy with its performance and workmanship.

Oh, about the hole, he made an exception and drilled it out for me but on the thinner back plate.

 

[Buckeye Amps]

Really, I thought the trigger is an option. Now I am tempted to get another one that I don't need. It would be even more tempted if you could do the Purifi, or at least offer the NC500. Any chance for that?

The trigger is standard. If not needed, I knock $5 off the price.
I am working on a longer term plan to eventually offer Purifi, but not at this time.

 

[peng]

The trigger is standard. If not needed, I knock $5 off the price.
I am working on a longer term plan to eventually offer Purifi, but not at this time.

Great, but until then, how about NC500? I like that its PSU is separate, and have a little better spec on paper.

 

[Buckeye Amps]

Great, but until then, how about NC500? I like that its PSU is separate, and have a little better spec on paper.

Not at this time. I am flooded enough with the NCxxxMP orders, it is easier for me to stick with the MP series for Hypex.

 

[YouCanCallMeGeorge]

Thinking about this some more, and noting the temperature of the bottom plate of the case, I think it might make more sense to buy some finned heat sink extrusion and attach it to the bottom of the case. <---Edit: While playing music. I'll add the standby switch for idle time.

 

[RickS]

Thinking about this some more, and noting the temperature of the bottom plate of the case, I think it might make more sense to buy some finned heat sink extrusion and attach it to the bottom of the case. <---Edit: While playing music. I'll add the standby switch for idle time.

Would not waste your time or money. Likely this module is defective and should be under warranty.

Unless you think you caused it to be damaged, get it replaced. If you prefer to discuss more discretely, PM me and will help as best I can.

Rick