Technics SE-A900S

Jump to Latest
#41
Kim666 said:
I don some testing, I replaced the original fan whit a 80mm noctua computer fan driven on a external power supply so it runs all the time and cranked it the volume to where I use to listen and after 2 hours the temperature on the heat sink is 35c…
Click to expand...
Thats good!
Kim666 said:
now i only have 1 problem and that is if I turn volume up to the point where the fan supposed to turn on the amp going into protection
Click to expand...
Thats not good!

Can you read the corresponding peak watts from the frontal power meters and post them?
 
#42
hbtaudio said:
The SVI3205B current amplifier is definitely a BJT Standard EF. According to the original Class AA doctrine, its power dissipation should not be significantly greater than 2 * 2.5W. 5W does not generate 60°C at the existing heat sink in idle mode. The left banger, the RSN6000B with its MOS fets will be the culprit. My guess is up to 2 * 20W (completely unnecessary) power dissipation. If this is really the case, then the temperature found is actually the normal state. With the maximum power output of 2 * 70Wrms (into 8 ohms), i.e. 140 to 45, this would be quite atypical.

An interesting case.
Click to expand...
Thank you 😊 since all 3 of my power amps get equally hot I think it’s normal, but why I like to get the temperature down is cos I really love that amp and want it to last.
 
  • Like
Reactions: hbtaudio
#47
hbtaudio said:
These are all great amplifiers - and I'm happy for you that you saved them from being scrapped.

I would also like to have an SA-E1000MK2 😉
preferably without a fan, but with the old heatpipe.


+1

enjoy
Technics Audio
Click to expand...
Yes what can I say, I really like Technics, 😊

a thought that occurred to me regarding the dummy load. what if I just attach the original fan motor somewhere (solder longer leads)?
 
#48
look
1732450522768.png
 
#49
In idle mode, the heat sink should therefore not get more than slightly warm to the touch. With a power consumption of 10Wrms, for example, this is no longer the case.

Why don't you leave one of the amplifiers with the lid open and without signal control, no ac signal, no load ... 1h in idle mode and measure the temperature of the heat sink every 5 minutes.

Stick a temperature-dependent resistor in the middle of the heat sink, do not measure with this infrared thermometer for example Peak Tech ...
 
#53
The best you could do to keep the amp in good shape is reflowing the soldering of the power modules, and perhaps a few more bad connections that could have suffered from heat or age. Unfortunately, this will require a major disassemble because I don't think the bottom plate can be opened or taken off.
 
You must log in or register to reply here.
Top Bottom