Hello,
ive just built the K8060, mounted it on heat sinks, given it a 0-30 0-30v 130VA transformer and i cant turn it on for more than a second as the 0.47 5w resistor glows bright orange and looks as if its about to shatter, as well as that there is also a hum and everything vibrates, what could cause this?
Most likely an assembly mistake such as swapped power transistors or soldering errors.
We suspect that you did not perform the lightbulb test, as indicated in the manual.
Check assembly and replace transistors if necessary.
ok i’ve checked my assembly and re soldered the joints and it turns on without glowing now, but when i turn it on to set the bias i get a reading of -33mV, is there any reason for this? my DMM is working fine as ive been using it recenty and checked it after that reading.
thank you for the help
Ricky
But is the amp working?
the amp worked with an ipod attached to a 47k pot to the input, when the pot was about 1/4 of the way the music became extremely distorted which i would expect is part of the bias problem.
ok ive replaced the transistor attatched to the bias control, checked my DMM, replaced batteries, checked all power connections and tried again, i am now reading a bias of 4mV at the highest point this can be, music still play fine to a point, then it becomes extremely distorted, im using 4x 8 ohm 50 watt speakers (2 in series 2 in parallel). what can i do now?
Bias current is too low.
Check bias part of the circuit. If necessary, replace the semiconductors.
ok i think i have it working now, a last question, what is the lowest and highest voltage that should be put into this amp? and will this amp distort when it is overdriven or will it just overheat/fail/break.
Lowest : 0V (strange question)
Highest input level for full output power: 600mV
When overdriven, amp will produce square wave output, which is harmfull especially for tweeters, so take care.
thank you, by lowest i meant where will you start to hear noise from the amp, and over 600mV will overdrive it? and with the volume pot before the amp, will the 47k resistor on the circuit board need to be removed for it to function correctly?
No need to remove 47K resistor.