Secret of Lovely Cube :
Many Users of Lovely Cube are worrying about the temperature of various parts of Lovely Cube.
Belows are the worries found in the Head-Fi forum :
- I wouldn't even try putting my finger on any of the transistors or voltage regulators on mine.
- Is it ok for 4 output transistors on radiators to be burning hot? After about one minute, I can't just touch them for longer than 0.5 sec
(However, it is not instantly burning my fingers, so i assume temperature is lower than 100 C )
.Two stabilizators are just warm
Remember that Class A Headamp is built to hear , not to touch.
In order to smooth the worries about HEAT in Lovely Cube , here I disclose the SECRET of Lovely Cube (also for Lehxxxn)
SECRET of Lovely Cube :
- It runs in Class A (everyone knows) , In Class A , NO HOT NO GOOD.
- The 4 output transistors (BD139/140) have BEST performance at about temp 70°C
- The 4 Capacitors (470uF) have BEST performance at about 50°C
This is the heatsink used in Lehxxxn . Does Lehxxxn want to save few dollars on Heatsink ? Absolutely not. They use this small heatsink in order to let the transistor heat up to about 70°C . Salute to the Lehxxxn PCB designer, they arrange the 470uF capacitor nearby this heatsink (act as a heat radiator) to let 470 uF capacitor be heated up to about 50°C .
Also Salute to the Lehxxxn Case designer , the long rectangular shape case trap the heat at accurate position.
My Advices :
- Don't try to cool down the transistors by changing large heat sink or remove and mount on the case . No worries about burn out the transistor , the transistors' (BD139/140) max. junction temp is 150°C (http://www.datasheetcatalog.org/datasheet/fairchild/BD139.pdf)
- Don't try to make holes on the case for ventilation. This doing will destroy the heat traps.
- Use similar case. It is recommended not to use large case, large case cannot trap heat well.. If cannot find suitable case , buy from me :) .
Research for you :
I got a new Toy - Infra Red Thermometer
Result of temperature at various area
On the other hand , OPA should not operate in high temperature, although the max operating temperature of , for example, 627 is 80°C. In my opinion , the best operating temp. of OPA should be 40-50°C
Below is the GIF animated , total 9 pic each 5 seconds , describe the making dual 627 adding with heatsink. After using this , the temperature of the heat sink is about 40°C.