Working on some “450w” kits. I figured the rating was for 4 ohms, with the OP and drivers rated at 230vce, I stuck it into a +/-90vdc psu. Tested and got about 350w/8e and 550w/4e at clipping. The kit survived, one of them is in service running the mid woofers in my HT system for a couple of years now. As I look around to make a few mods in another one of these, I notice the input stage comprises mainly of 2sa970 and 2sc2240’s. If memory serves these are 120vce devices.... and they are subject to the full 90vdc on their emitters. I am wondering if I should change them out for something in the higher voltage range or leave them in there.
Any suggestions?
Any suggestions?
Leave them there , used them many times never had a problem with them .
Low noise audio BJT,s 2SA970 Vce=120V and notice only 2ma required for bias.
The 2SC2240 is its matching npn, same spec.
Of course you can "update " but I liked them so much that I purchased
a bundle of them long ago .
Low noise audio BJT,s 2SA970 Vce=120V and notice only 2ma required for bias.
The 2SC2240 is its matching npn, same spec.
Of course you can "update " but I liked them so much that I purchased
a bundle of them long ago .
Thanks Duncan, I am fine with the acoustics. I surmise I am not running them over spec, ie, each device never sees both rails (180vdc)
The high voltage rail is used to allow large peak signals to be used without clipping at the output, its standard practice to use slightly less than the full voltage rail BJT,s to allow for correct operation under various conditions relating to the design of the amplifier in small signal devices.