Amp doesn't work as it should, Vbe multiplier doesnt work, changed it with 3 diodes resistor, 4 diodes. Changed transistors , same behavior ca not turn them on enough.
Some drawing mistake or something connected bad. It sounds like severe crossover distortion. I need to check again..
Some drawing mistake or something connected bad. It sounds like severe crossover distortion. I need to check again..
He said 100 watt amp, 150W 4 ohm speaker, +/-35V supply. in post #1. The +/-35V is a little thin unless the transformer is huge so the voltage stays up to around +/-32 at load. More unloaded supply voltage is needed with a typical 200-300 VA transformer which would be used. Either way the transistors on hand are fine for the purpose.
For 100 watt 8 ohm/150 watt 4 ohm you want +/-50 supplies. That’s two pair territory, even with MJ11015’s. One pair of 15003/4 would be marginal, 15024 or 21194 better if you insisted on one pair. Two pair of any of the 100 or 150W flatpacks would be better - and cheaper.
For 100 watt 8 ohm/150 watt 4 ohm you want +/-50 supplies. That’s two pair territory, even with MJ11015’s. One pair of 15003/4 would be marginal, 15024 or 21194 better if you insisted on one pair. Two pair of any of the 100 or 150W flatpacks would be better - and cheaper.
Darlingtons do bias kind of funny since you measure DRIVER current as well as output. It starts to come up, levels off, then has to start increasing rapidly again before the outputs see any bias. Fully class B with EF2 has severe crossover distortion. With EF3 it can be acceptable.
I changed the outputs with 2sc4468 / 2sa...
Just to test, and they dont bias either. So something is not right.
Just to test, and they dont bias either. So something is not right.
You can determine where the base is with diode scale of a dvm. ~0.6 v forwards to two other pins, is the base. Measure one that is not installed yet, subsequent & previous semiconductors can mess up in pcb measurement.
Manufacturers can change the pinout or any other specification by publishing a corrected datasheet THAT DAY. Download datasheet & read every time you buy from an authorized distributor. ON sold me TO-220 package TIP142/147 by changing the package suffix. Stupid me, I bought them.
Manufacturers can change the pinout or any other specification by publishing a corrected datasheet THAT DAY. Download datasheet & read every time you buy from an authorized distributor. ON sold me TO-220 package TIP142/147 by changing the package suffix. Stupid me, I bought them.
A1015’s do go ECB. But your post says C1815. Which also goes ECB. But make sure you dont swap NPN and PNP.
At least the original Jap versions are supposed to, and you can get Korea (KSA/C) that do. But you do have to be careful about Fairchild/ON KSA/C. Some of them are available both ECB and EBC depending on the suffixes in the entire part number. I use the EBC versions of the C1008 as I use it as a replacement for MPSA06.
At least the original Jap versions are supposed to, and you can get Korea (KSA/C) that do. But you do have to be careful about Fairchild/ON KSA/C. Some of them are available both ECB and EBC depending on the suffixes in the entire part number. I use the EBC versions of the C1008 as I use it as a replacement for MPSA06.
I tested them before putting in with LCR meter, they showed fine also pinout there. Also checked with mutlimeter before putting them in pcb i always do, seems fine.
What actually does it do in the circuit there? Some kind of bootstrap?
What value would be best, does it matter much rhe value?.
What value would be best, does it matter much rhe value?.
That would certainly eff things up. It’s supposed to be the bootstrap. 47, 100 uF is fine. It gives an open loop low frequency pole with those two collector resistors (parallel combination).
The TIP142/7 snafu is certainly a bunch of bull$#1+. The rest of industry made the TIP142 strictly in the TO-218 case, and later swapped over to the COMPATIBLE TO-247. Again, industry wide. They SHOULD have called them MJE142/147 when stuffed into TO-220’s.
The TIP142/7 snafu is certainly a bunch of bull$#1+. The rest of industry made the TIP142 strictly in the TO-218 case, and later swapped over to the COMPATIBLE TO-247. Again, industry wide. They SHOULD have called them MJE142/147 when stuffed into TO-220’s.
Due to its unique connection of the bootstrap cap to the DRIVER emitter instead of the speaker output, when the bootstrap cap gets leaky in the old Phase Linear (400 or 700) the speakers output just heads straight for the + rail and latches there. No speaker protection as stock either and you know how that would end. None of the readings you take on the PCB make any sense at all when it happens too.
Bootstrap caps are one of the first things checked now. Across the board.
Bootstrap caps are one of the first things checked now. Across the board.
Congratulations. I have no idea what a "bootstrap cap" is good for. I don't believe Apex AX6 or dynaco ST120 either has one.
If you have a "crossover" appliance, that sums the bass of 2 ehannels in, outputs to a sub output with a cutoff frequency set by a knob or switch, you are fine. If somebody, like a roadie, might plug a 75 watt guitar output into the amp, then you both need to protect against overvoltage, and protect against high frequency coming into this amp.
If you have a "crossover" appliance, that sums the bass of 2 ehannels in, outputs to a sub output with a cutoff frequency set by a knob or switch, you are fine. If somebody, like a roadie, might plug a 75 watt guitar output into the amp, then you both need to protect against overvoltage, and protect against high frequency coming into this amp.