PCLxx/ECLxx amp

[6B4G]

Happy New Year to everyone
After all this time I decided to build the little amp as per the schematics on this page viewtopic.php?f=4&t=6997&p=56365&hilit=pcl82#p56365
I used a new 190vac transformer with NOS 5K 5Watt opts, my question is the R1 470R 3W resistor gets quite hot, over 100 degrees Celsius within 5 minutes. Should it be that hot?
The voltage at C1 (100uF) is 212.5vdc and C2 (100uF) 161vdc does that sound about right? Is there something I need to change

Regards
Greg

[bone]

Because your transformer is 20v higher in output than that recommended, the DC voltage out is also higher. Your voltage measurements show that the 470 ohm resistor has some 51v across it. this equates to a power of just over 5.5w. (VxV/R) The resistor therefore needs to be rated at least 7 watts or even, to be on the safe side, 10 watts.

[6B4G]

Thank you for the help.
I'v just added a 330R 10 watt resistor and ran it for about 10 minutes and the temp is sitting at 80C.
Voltage went up by 10v (172vdc) it should be ok now, I'll run it for an hour or so tomorrow morning and run
some more tests. I can say though, for a little amp it sounds quite nice, not great but nice.
Thank you again
Greg

[mike567]

You might want to try some shade or plate to plate feedback smooth things out. only takes a resistor

[6B4G]

Thank Mike
regards
Greg

[6B4G]

Amp has been built and amazingly it sounds good for a little amp. I’m impressed. It’s a great little amp for an office.

[mike567]

Nice build. Who made the chassis?

[6B4G]

I've had this chassis for years I think Chinese but.

https://modushop.biz/site/

This is a nice site and the prices are OK for a European company they have a large range.

This is another site https://www.audiophonics.fr/en/aluminiu ... -6276.html