Brumjam

01A Preamp Builders Unite!

69 posts in this topic

Super Wammer

Looking very good Richard :^

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Super Wammer
1 minute ago, MF 1000 said:

Looking very good Richard :^

Agree that looks excellent.

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I figured that if I made it exactly the same as the 26, as far as possible, there would be less variables.  After all, the 26 works laid out like, that so why change it?

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A little more progress.  The top plate is drilled,just (:shock:) the polishing to do.  A handy tip; don't break a 2.5mm drill bit in 6mm marine grade alloy!  I tried punching it out, drilling it out, swearing it out, in the end I used a masonry nail to punch a hole next to it and then forced it out.  Of course a 4mm hole became a 6mm hole!  :doh: Hooray for washers.  

I had a pair of chromed D handles, so they went on.

20170214_145926_LLS_zpsf8qx3pnn.jpg

Heatsinks, chokes, caps, 8 way umbilical socket and fuse holders fitted, plus aly foil lining. Parts are arriving in dribs and drabs, but the selector switch, bushes for the control shafts, and valve mounting discs need making now.  

20170214_150100_LLS_zps0rux9mgn.jpg

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Super Wammer
29 minutes ago, awkwardbydesign said:

A little more progress.  The top plate is drilled,just (:shock:) the polishing to do.  A handy tip; don't break a 2.5mm drill bit in 6mm marine grade alloy!  I tried punching it out, drilling it out, swearing it out, in the end I used a masonry nail to punch a hole next to it and then forced it out.  Of course a 4mm hole became a 6mm hole!  :doh: Hooray for washers.  

Tried Cobalt drills? Tougher than normal HSS drills, and stay sharp for ages :^

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It's not the cutting tip that's the problem, but the narrow shaft binding in the hole and snapping.  I was drilling with a cordless and not the pillar drill, so had less control.  

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Super Wammer
27 minutes ago, awkwardbydesign said:

It's not the cutting tip that's the problem, but the narrow shaft binding in the hole and snapping.  I was drilling with a cordless and not the pillar drill, so had less control.  

Cobalt drills are less likely to snap off.

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Selector switch made, out of left-over wafers and Delrin.  It's hard to get the spring loaded ball bearing to make a positive stop action, but I'll see how it performs.

20170215_183352_zps2vfiv11j.jpg

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All drilled and fitted, including valve mounting plates.  Now I have to take it all apart and polish the top!

20170217_161018_LLS_zps7v9apxaj.jpg

20170217_160743_zpshudpfxe4.jpg

 I need another 12 RCA sockets, and my favoured Valab rhodium plated jobbies are £16 for four, so over £50 for the 12!  But he is selling what looks like the same sockets (CMC?) with copper plating for £5.50 for 4!  So I am going to try those.

s-l500.jpg 

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