Mezmerize DCB1 Building Thread

$7 piece of cake

I couldn't wait for a proper enclosure and I thought a cardboard box was probably a bad idea on this one, too many connectors/knobs/heatsinks. I got a cake pan and went at it with a step-bit for all the holes.
IMG_20201217_072155172.jpg IMG_20201217_065909451.jpg
I listened to some vinyl last night (w/UFSP as the source) and it seems like a definite improvement over my old Hafler pre.
 
I appreciate the encouragement - My wife said "is that what you've been working on... is that a cake pan?" good thing is she is use to crazy creations showing up in the livingroom.
IMG_20201218_172600263.jpg
I used the matched quad from punkydawg that was ~9ma idss in the audio section and ended up with -1.1mV and -1.0mV DC offset on the output. Overall seems like a great upgrade in my system. Now I just need to get the 6-24 crossover and a pair of F6 built.
 
Last edited:
Dropbox - Finmez1.JPG - Simplify your life
I built this in 2018 and it was the best thing ever.
But I tried it again recently and found the volume control unreliable, switching from low to maximum just by touching the control. The effect could be reproduced by touching the input wires too. Testing seemed to show the volume pot was intermittently switching from 20kR to 0R.

A bit depressed and not knowing where to start, I browsed around, somwhere someone said "the pcb pins can be tight and forcing them in can break the continuity between top and bottom".
This might be my problem? I can probably reflow the solder for the pins top and bottom without dismantling the whole thing using a flux pen.
What do you think?
 
diyAudio Chief Moderator
Joined 2002
Paid Member
Its not a systematic fault in DCB1 builds I could give info about, at least I don't remember a PCB eyelets related problem reported in the threads. I might be wrong, someone else may have specific info. In any case its a practical fault and it takes inspection with the meter while pulling and pushing related cables with medium force until finding the weak spot.
Can be the pot's rotation contacts alone. Or a tiny fracture on the main PCB or on the pot's wafers. Or a cold joint wire connection to them. Then to reflow it, jumper it, change something. If all joints continuity seems good, substitute with a pot you might have in a spares box to compare if the now one developed a mechanical fault. Any quality or kΩ value will do for such a basic test.