Some more pics: These are just some pictures showing case detail and my layout. I have not yet finished the seams, and there fore the case has not been prep'd for paint. Yes. the screws will be painted as well.
Inside layout. The whole of the left side, where the pre-amp will live, will be packed with sound / vibration deadening foam. Pictures of that will come later. If you look hard enough, you can see the separator shield I have installed to shield the PS from the amp. I'm hoping that, in addition to locating the transformer as far over as possible, that shield will keep induced hum from the PS out of the amp.
You can also see the mods I've made to the amp to remove the original on-board PS. The LED mounted on the new PS is temporary. It will be removed when I connect the indicator lamp of the power switch. A nylon wire tie will be placed around the transformer prior to final mounting as well. This transformer was a plug-in type - that is, it had the prong for a wall plug made in to it. For mounting on the PCB, I cut the prongs short enough to solder to the PCB. At this point, that joint is all that holds the transformer to the PCB. Granted, it is a silver soldered joint and very strong, I still want the extra insurance of a wire tie to secure the transformer to the board. I've also hatched an idea that may add a little extra insurance against hum by wrapping the JAN6418 tubes with enameled bell wire and connecting that wire to GND. I don't believe that will upset any capacitance with in the tube and cause instability, but do invite comment on that..
Attachment:
layout.jpg
In the upper left of the picture, you can see the phono jack PCB. After drilling the holes for it and see how it looks, those are going bye-bye. I will instead clean-up the holes that I drilled for that concept and make it a square cut-out and then fabricate a new jack PCB using nice new jacks. I have some 1/8" acrylic that will be use in conjunction to strengthen that concept, if necessary. That's primarily why I didn't show you the back side where the jacks and IEC receptacle will be mounted. Those jack holes are UGLY.
Attachment:
outside.jpg
Picture of the seam detail. For this reason, I'll not purchase anymore Bud boxes. The price was right and the size was good, now I know why the price was lower than a good quality Hammond box.
Attachment:
seam detail.jpg
The IEC ground will be connected to case. The rest of the circuitry will be isolated from case. By doing this, I should be able to avoid any system ground loops.
While I'm thinking about it.. My phono, like most, has a separate grounding wire. Should this wire be earthed, or isolated from earth?
.....stay tuned!
