mega lord
Centre tapped
Hello, as per the title I am a numpty.
I got out a pair of old NCC200 Rev1.3 from a year in storage and hooked them up to some minicap and EI transformers. I have four monoblocs using rev1.4 but wanted to try a 6 pack on my 3 way speakers so was going to add these for the tweeters.
To cut a long story short I used and old wiring loom and assumed that the wires were in the right place. Hooked everything up and did not notice that the negative DC from the minicap was connected to the 0V spade at the zobel output. 0V connection from minicap was incorrectly on the negative DC spade on the ncc200. Whoops..
I could not work out why one of the boards was 30mV for DC offset, voltage across the 0R22 power resistor was fine and the other board was showing just over a volt DC offset and zero mV across the power resistor. I eventually discovered my error having previously thought I had blown feedback cap, bias cap etc etc.
Powered down, discharged the minicap and corrected the wiring mistake. Turned back on and the board shows the DC offset to be 33mV. Phew ! Voltage across the 0R22 power resistor is normal and roughly what I remember setting them at a couple of years ago. It is slightly higher than the other board and I thought I had set them equal. No magic smoke or bad smells.
Have I been lucky and got away with this ? I don't know what else to check and all I have is a DMM. I could connect to some stunt speakers and check for distortion .
Many thanks, Stu
I got out a pair of old NCC200 Rev1.3 from a year in storage and hooked them up to some minicap and EI transformers. I have four monoblocs using rev1.4 but wanted to try a 6 pack on my 3 way speakers so was going to add these for the tweeters.
To cut a long story short I used and old wiring loom and assumed that the wires were in the right place. Hooked everything up and did not notice that the negative DC from the minicap was connected to the 0V spade at the zobel output. 0V connection from minicap was incorrectly on the negative DC spade on the ncc200. Whoops..
I could not work out why one of the boards was 30mV for DC offset, voltage across the 0R22 power resistor was fine and the other board was showing just over a volt DC offset and zero mV across the power resistor. I eventually discovered my error having previously thought I had blown feedback cap, bias cap etc etc.
Powered down, discharged the minicap and corrected the wiring mistake. Turned back on and the board shows the DC offset to be 33mV. Phew ! Voltage across the 0R22 power resistor is normal and roughly what I remember setting them at a couple of years ago. It is slightly higher than the other board and I thought I had set them equal. No magic smoke or bad smells.
Have I been lucky and got away with this ? I don't know what else to check and all I have is a DMM. I could connect to some stunt speakers and check for distortion .
Many thanks, Stu
