DIY speakers from years back... using Nokia LP 80 3" and Audax AW010 drivers.
Yes, they really do. The original design had just a cap for the tweeter, but then I copied the crossover of a similar design using an inductor and resistor, and it did wonders to the design. I’ve made a few of these for friends and family, and they work really well on windowsills or set close to walls. But seems like the 3” drivers are pretty much extinct now. The little brace at the bottom is copied from ProAc - I like the looks . 😊
0V across Q4 gate/source shows a problem. Are you sure the preset is turned to the correct end? Assuming it is then switch OFF and measure on ohms range between gate and source. This is just to make sure there is no short there.
Also what is the DC voltage at the amp output before the speaker coupling cap. It should be about 12 volts.
Also what is the DC voltage at the amp output before the speaker coupling cap. It should be about 12 volts.
okay, strange. P2 off one channel was set to the most counter clock position. i turned it clockwise.
now i have Q4 G/S ~ 4V
i set VB to 0,3V and V0 to 11,5V.
another interessting thin is -> the amp is now running for about 1 hour on my desk without anything attached. the heat sinks of the "functioning" channel are warm as they have been already in the past. the others stay still cold.
now i have Q4 G/S ~ 4V
i set VB to 0,3V and V0 to 11,5V.
another interessting thin is -> the amp is now running for about 1 hour on my desk without anything attached. the heat sinks of the "functioning" channel are warm as they have been already in the past. the others stay still cold.
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That all sounds OK. I can't say which way to turn the presets as I am just working off the circuit diagram but turning the wiper so it connects to the drain/s of Q1 and Q2 is the position that gives highest bias current.
Are you saying there is a problem in this other channel? Is the 12 volt reading OK at the output?