Mezmerize DCB1 Building Thread

That does it! Thank you Salas. You have been a great help and I really appreciate your help. Thanks to Andrew too.

No buzz when pre-amp is off.

There's a bit of buzz when the volume is turn up. You can hear it when it is turn up to o'clock. I think that is interference. When I touch the knob, the buzz is stronger.
 
When there's a source input, the buzzing is very faint. You only hear it if you turn the volume way up to maximum and put your ear about 1 foot away, even with the source power off. But if there's no source attached to the input and if you selected that particular input (the input without any source), the buzz is much louder. You can hear it with the volume turn up to about 9 o'clock.
 
Hi. Sorry to bother you again. It was okay an hour ago with some buzz but now the right channel is gone. The left channel is ok without any buzzing now, there's some hissing when volume turn to the maximum. It was buzzing along with the right channel when both channel were playing. The left channel DC output is at 1.5mV.
 
When there's a source input, the buzzing is very faint. You only hear it if you turn the volume way up to maximum and put your ear about 1 foot away, even with the source power off. But if there's no source attached to the input and if you selected that particular input (the input without any source), the buzz is much louder. You can hear it with the volume turn up to about 9 o'clock.

Some posts before I recommended you ground the pot's body with a wire. Did you?
 
Hi. Sorry to bother you again. It was okay an hour ago with some buzz but now the right channel is gone. The left channel is ok without any buzzing now, there's some hissing when volume turn to the maximum. It was buzzing along with the right channel when both channel were playing. The left channel DC output is at 1.5mV.

Check with DMM continuity that your signal wiring and T wires mod are still OK, also that your voltages are still OK. Did you hot-plug any input or output? I mean connecting/disconnecting when power was on.
 
The selector is not in the signal path. Its between relay coils power line and ground. No need to ground its body for hum/buzz. I hope nothing is gone since the voltages are still OK but take that wire out and see. What amplifier you have?
 
The selector is not in the signal path. Its between relay coils power line and ground. No need to ground its body for hum/buzz. I hope nothing is gone since the voltages are still OK but take that wire out and see. What amplifier you have?

I took the wire out but the right channel is not giving out any music. But it did make some sparking noise when turning on and off. I am using the gainclone.
 
I took the wire out but the right channel is not giving out any music. But it did make some sparking noise when turning on and off. I am using the gainclone.

Was alright playing, the voltages are still alright, have any clue at what point of operation one channel was lost? Compare voltages between left and right audio Jfets pins to ground, relay channels output offsets, to see if a Jfet or a solder joint is bad, or a connection is gone in the bad channel. Also see continuity between input and output for when the output relay is activated. To know there is signal path for the problematic channel indeed.
 
Truly wonderful. I have a NP B1 clone...the green board that was sold in the DIY store. It was power by a 18v power supply. Cleary, there is a different between the two. Amazing! Same circuit minus the capacitors and a different power supply makes a lot of difference. The bass is more firm and solid. The mid is more refined and focused. And I think I hear a bit more details too. I am using Peter Daniel's gainclone. I believe witha better volume control, it'll be much better.

And I learn more by mistakes. Thanks to Salas.
 
Hi,
I'm Just getting together the BOM for the MEZ - Does anyone have an opinion whether a motorized Alps '47 (on the PCB) will add any EMF distortion/noise?
Should I 'remote' the motorised assembly to the front of the case / Or just get off my *** and adjust the volume with the standard 'Blue Beauty'?
Steve.
 
I try to remember but I can't seem to recall any build with a motorized RK27 blue velvet directly on a Mez. Simple logic says if it works on so many self standing remote receiving volume + relays selector combo boards, why give any grief to the Mez, but its not a verified hypothesis.