1 (edited by Michelle242 2021-06-10 19:11:32)

Topic: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

I have severe heating issues with my ADI-2 Pro FS in my hot (28 degrees Celsius) little studio.
This is how I'm trying to solve these issues lately. Thought I'd let you know. big_smile

https://i.ibb.co/8mX01FS/E55-E87-B1-0-FFF-4-E09-BECE-44-EB192-E48-B6.jpg
https://i.ibb.co/ygWwSWQ/5-C96-A768-3541-4-B39-BB55-738389-F641-BC.jpg

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

Nice fins. tongue My old ADI-2 Pro FS used to get really hot, you could almost burn your hand on it. The ADI-2 Pro FS R I have now seems to suffer less from this problem somehow.

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

Hehe thanks! wink
Well maybe I'll get the new one next year or so.
I think it also depends on the headphones and the impedance you have connected.
Currently I'm driving a Campfire Solaris in balanced mode.
It is connected to both the outputs and that might be a reason for my current severe issue.
With a normal stereo headphone connected I can remember the issue was not so severe.

4 (edited by ning 2021-06-11 01:53:33)

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

you can install a k thermal couple inside the unit, on top of one of the 4 OPA1602s right before the ADC chip --- that's the hottest area on the PCB. when idle, it's usually 36C hotter than your ambient room temperature. try each cooling method you want to experiment and see how much temperature is reduced.

Heatsink like this seldom works. most of the heat dissipate from the bottom, not the top. top is only 14C hotter than room, while bottom is 21C hotter. I tried heatsinks on top of the unit and on top of the chips, and the temperature remains almost the same inside.

moving heatsinks to the bottom may significantly improve dissipation, compared to what you are doing right now.

the most efficient way to cool down the unit passively: install the thermal pad not to the top, but between the pcb and the bottom, to improve the thermal dissipation from the unit to the bottom. this makes the bottom of the case even hotter (25C hotter than room, but it's a good sign!). it would cool the chip at least by 3 C.  then you have two options to further improve it:

1. if you have a wooden desk, install a few rubber feet and raise the unit by a few centimeters to allow more air to flow below the unit. that would cool additional 2 C.
2. if you have a large metal desk, install another thermal pad between the bottom and your desk. this works very well, and would cool additional 4C.

Nicked_Wicked wrote:

Nice fins. tongue My old ADI-2 Pro FS used to get really hot, you could almost burn your hand on it. The ADI-2 Pro FS R I have now seems to suffer less from this problem somehow.

very likely your ProFS is broken. these two devices generate similar amount of heat. if you put two under the same condition, they should consume similar amount of energy.
a broken shorted opamp channel in the headphone out for instance, would make the unit generate at least 6W more heat, while the functionality is unaffected.
a power adapter with power meter would easily verify if the unit is running normally. usually it should be 10-12W when idle. if it's consuming much more than 12W, your unit is broken.

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

Thank you for these valuable informations! Do you really think the unit is broken? I will have to validate that. I have a few current measuring sockets.
What do you don't see on the photos btw: I have already raised the unit about 1,5 cm with very thick rigid foam feet. This should also help a lot. And you recommended this, too.
I will have to see if the unit heats up until it turns off the operation again.
Did not happen so far so I'm confident. smile

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

Michelle242 wrote:

Do you really think the unit is broken? I will have to validate that. I have a few current measuring sockets.

when idle, if it consumes much more than 12W (for instance 15-20W), the unit is broken.

Under normal condition the unit does run very warm. That why RME ADI-2 DAC is recommended if you don't need ADC. that product runs a lot cooler.

7 (edited by KSTR 2021-06-12 00:28:12)

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

I run my Pro's vertically (left side down as the headphone amps are located there) and that allows effiicient airflow through the device for convection cooling (chimney effect) -- of course with some sort of spacers so that the slots in the cover are not blocked. Also the bottom side then can radiate the heat into free space. Turned out to be very effective, though a bit unconvenient to operate the device and read the display.

ning wrote:

you can install a k thermal couple inside the unit, on top of one of the 4 OPA1602s right before the ADC chip --- that's the hottest area on the PCB. when idle, it's usually 36C hotter than your ambient room temperature. try each cooling method you want to experiment and see how much temperature is reduced.

This (ADC driver 1602's as hottest spots) is only true when the headphone amp(s) are idling. Once those have significant work to do, the 1688's get hot and heat up the whole PCB in that area.
I measured about 65°C (after 30minutes, at 25°C ambient, open case, using thermal camera) when driving 8 Ohm dummy loads to just below the point the overload protection triggers, which is also depending on PCB temperature by the use of PTC's used to sense the supply current of each headphone channel. Closed case probably another 10..20°C more. OK, a somewhat unrealistic operation scenario.

Anyway, diverting the heat inside the device with internal heatsinks won't improve things much. Airflow for convection cooling is the most efficient way IHMO.

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

Thank you for all the help so far. I have measured the power consumption and it is exactly 12W in idle, so I guess the device is functioning properly. *phew*
I have yet to check the heat development under heavy load.

9 (edited by Michelle242 2021-06-14 17:39:19)

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

Okay, I have recognized that the heat development is definitely more problematic when I have connected my Campfire Solaris In Ears. With only the output XLRs connected to my Violectric HPA 281 the heat development is a lot less.
And since I have applied the heat sinks, the overload warning and the output mute with the In Ears is gone.

Re: How I'm trying to overcome the heating issue of my ADI-2 Pro FS

For anyone wondering why I don't connect the In Ears to the Violectric amp:

The In Ears are incredibly sensitive and the background hum of the Violectric is just too loud for them. This is normal. I have already talked to the developer Fried Reim about this and he recommended me to get a new model which does not have the problems.
With my over ear headphones (ATH-ADX5000) the hum of the Violectric is not audible.