Bottlehead Forum

Bottlehead Kits => BeePre => Topic started by: Deke609 on January 05, 2019, 10:33:45 am

Title: Crazy with the copper shielding
Post by: Deke609 on January 05, 2019, 10:33:45 am
I just retested my voltages after burning in my BeePre for a month (all good) and thought I'd  take some pics while it was on my work table.

I went a bit nuts with the copper shielding and shielded as much of the signal and power supply wiring as I could.  :D

The copper pipe is refridgerant tubing and readily takes a bend - pretty easy to work with.  I also used copper braid both on its own and in conjunction with the tubing for shielding the wire sections that run from the tube ends to destination points.  There's a bit of copper foil tape in there too. I also added  flux bands made of 30 awg copper sheet to the transformers.  Shielding and flux bands are wired to chassis ground.  Areas that might potentially come into contact with another wire or terminal are wrapped in variously colored electrical tape.

I have no idea whether any of it makes a sonic difference b/c I haven't heard the BeePre without the additional shielding - so it might be zero. And it added days to the build time. But I enjoyed the process, so it was worth it.

The large washers below the 300B tubes were needed to fit the teflon sockets I installed. The teflon sockets are smaller in diameter than the sockets supplied with the kit, so I needed something to snuggly seat them against. The sockets are separated from the washers/chassis on the underside by the supplied orange silicone o-rings. At some point I will cut the washers down to uncover the covered portions of the venting holes and countersink the bolt holes so that the tubes can sit flat against the sockets. For now and the foreseeable future I am only using the BeePre for headphone listening, so the likelihood of a microphonics problem was slim - the sockets were just a late night impulse buy, and since I had them and paid for them, I figured I might as well install them.

Lastly, I clad the wood base in 30 awg brass sheet, in the same manner as I clad my Stereomour II in copper. I wouldn't do this again. Brass is much more resistant to bending than copper and was a real PITA to work with. And it came out looking a bit like foil gift wrap. But I think that will improve as the brass oxidizes over time.

I originally planned to make some brass coverings for the transformer end bells, but abandoned the idea after the trouble I had cladding the base. I'd still love to have the end bells in real brass, so if anyone knows of and can post a source for them, I'd be very grateful.

cheers and Happy New Year all,