Adding cooling fans to Accuphase Class A E-700

[lockon]

What are your thoughts on adding cooling fans on top of the chassis of an Accuphase Class A E-700?

I’m not a big fan of the manufacturer’s design choice of placing the heat sinks inside the chassis. In terms of real-world use and reliability, Accuphase has never had any major issues.

However, the entire unit feels like an oven in the summer. The internal components—especially capacitors—will likely experience some reduction in lifespan under high temperatures.

I understand that adding cooling fans isn’t necessary, but I’d still like to try it. I plan to run the fans at very low speed so they remain quiet, with airflow set to extract hot air from inside the chassis. I estimate this could lower the temperature by around 10°C.

Would reducing the temperature in this way affect the operating conditions for which the manufacturer originally designed the circuit? If not, the only downsides I can think of are potential electromagnetic interference and increased dust being drawn into the unit.

Thanks!

 

[Mike_Trueman]

Can you read the temps on the display? A class-A amp works better when it is hot.
The gap between the fan and the case is to big to work with those risers. No gap works best for extraction from the inside.

Temperature sensors that detect the heatsinktemperature are installed on the heatsink. Thanks to this,the unit accurately ascertains the high-temperature alarmin the power amplifier section.

 

[lockon]

No, I can’t. I used a laser thermometer to measure various points on the heat sinks inside the chassis, and the hottest spot reached about 58 °C.
Those are silicone risers; they can help reduce vibration from the fan. I can remove them for sure.

 

[Mnyb]

Turn off the amp when not listening ?

 

[Mike_Trueman]

I would now worry if it gets to hot. It is desinged this way and it will give an alarm if it is to hot. My class-D Hypex amp is running at 50 °C all the time.
The Class A operation of those MOSFETs means that they are always on to see the E-700 pull 178 Watts from the wall whether playing music or not.

Does the amp have holes on the bottom?
This guy made a class-a amp it 5 degrees cooler but it is not much so i would not do it.

 

[wwenze]

Having a bit of space for free airflow in front of a fan's intake side improves performance. Source: Computer DIY forums. I would keep the risers to reduce vibrations.

Would reducing the temperature in this way affect the operating conditions for which the manufacturer originally designed the circuit? If not, the only downsides I can think of are potential electromagnetic interference and increased dust being drawn into the unit.

Cooling is a fun topic. I've had power supplies destroy themselves because I removed a piece of plastic to improve the airflow.

Especially in high power electronics, the amount of heat and temperature and airflow of each component is known during design, but often you only have one or a few temperature sensors. Changing the airflow disrupts that order and for example you can have a CPU fan run slow because the CPU is running cool but the VRMs that depend on CPU fan will overheat. People who watercool their processors know this too well.

But for something like Accuphase Class A E-700? It doesn't matter. There is no active cooling, it does nothing to keep itself cool, it does not need to do anything to keep itself cool, so it's a "meh whatever" for what you want to do. So, yes, dust and EMI are your only worries.

 

[Ruediger]

What are your thoughts on adding cooling fans on top of the chassis of an Accuphase Class A E-700?

I’m not a big fan of the manufacturer’s design choice of placing the heat sinks inside the chassis. In terms of real-world use and reliability, Accuphase has never had any major issues.

However, the entire unit feels like an oven in the summer. The internal components—especially capacitors—will likely experience some reduction in lifespan under high temperatures.

I understand that adding cooling fans isn’t necessary, but I’d still like to try it. I plan to run the fans at very low speed so they remain quiet, with airflow set to extract hot air from inside the chassis. I estimate this could lower the temperature by around 10°C.

Would reducing the temperature in this way affect the operating conditions for which the manufacturer originally designed the circuit? If not, the only downsides I can think of are potential electromagnetic interference and increased dust being drawn into the unit.

I did something similar once with a big Yamaha AVR. Just class AB but ran very hot in the racks, despite decent space around it.

Used a double ball-bearing fan connected to rear usb. Low rpm, so it could not be easily heard. Big diameter, I think it was 12cm, so it moves some air. That did the trick pretty good.

You don't want too much airflow so the air inlets will get clogged with dust. The openings have a certain size that will hold back bigger particles and let enough air through. But to not suck tiny dust in (in big amounts) the airflow has to be under a certain speed.

I did not experience shutdowns due to high temperature, just felt it was necessary in the summer. After all heat is a cause for degradation.

Most appliances should be designed properly to stay cool enough when people regard the instructions in the manual. Those would demand not only a certain space above but also to the sides. Everywhere air can enter and leave.