Crack-a-two-a Build Log

[Doc B.]

Looks nice!

[Karl5150]

Button caps, acorn nuts and all that polishing. It's all in the details. Good work.

[JamieMcC]

Nice work looks great

[L0rdGwyn]

Thanks for the compliments!  The circuit is coming along nicely, should finish it in the next two days.

Question for Doc/PB - how crucial is it that the 220 Ohm resistor bodies be flush with the the A socket leads?  Because I am using non-stock sockets, the resistor body between A2 and 12U is about 1cm away from A2, as close as I could get it with the leads.  Just so happens that A2 is about as far away as it could possibly be from 12U with the socket orientation the way it is.

[Paul Birkeland]

It's always a tough call to make without having it sitting in front of me.  Do your best to get them as close as possible. 

[L0rdGwyn]

Uh oh, hope it won't cause problems. Here is a picture, for both A2 and A7 the resistor body is about 8-9mm away.  If necessary I could desolder everything and flip the socket, might get me another few mm.

UPDATE: I am reorienting the socket 180 degrees, should solve the issue.  Thanks for the help, PB.

[Doc B.]

UPDATE: I am reorienting the socket 180 degrees, should solve the issue.

Using the stock socket in the as designed position will solve the issue. Rotating the socket 180 degrees is begging for a miswire.

[L0rdGwyn]

Thanks, I checked and double checked the wiring of the 9-pin, rotating it 180 got the resistors where they needed to be.

Here is a picture of the stock circuit.

I am having a weird issue with my resistance checks, in that I cannot measure them at all.  I have my negative lead on the #8 near the IEC, I get a 0 Ohm reading at the power transformer screw, then cannot measure anything across the transformer.  Checking for continuity also gives no result at any transformer terminal.  This is consistent across two different multimeters and they are set to the correct range for each reading.  Fuse is not blown, all tests up to this point were passed, reflowed all of the joints at the transformer, power switch, ground bus, IEC.  Feel pretty dumb like I'm missing something obvious here, any suggestions?  I've been staring at this circuit too long.

[Paul Birkeland]

I have my negative lead on the #8 near the IEC, I get a 0 Ohm reading at the power transformer screw, then cannot measure anything across the transformer. 

Only the transformer screw with the ground tab has to be 0 ohms.

I checked the resistance readings in the manual and I do not see any resistance checks for any power transformer terminals.

[L0rdGwyn]

Only the transformer screw with the ground tab has to be 0 ohms.

I checked the resistance readings in the manual and I do not see any resistance checks for any power transformer terminals.

Ah yes, knew it had to be something dumb on my part, this is what happens when you are working night shifts and build this circuit in two sittings.  Thanks for humoring my stupid question regardless, PB.

All resistances and voltages are within spec - time to give this baby some head-time!

Here are some beauty shots, really pleased with how it came out aesthetically.

COMING SOON: TwoQuiet attenuator upgrade, Bottlehead Power Cord, and ridiculously large output caps

[faskenite]

I’m in the middle of a tricked out Stereomour build - maybe i’ll follow your example!  I’m planning on keeping the brushed aluminium top plate as is, but could you share as to how you got the mirror finish?

[L0rdGwyn]

I’m in the middle of a tricked out Stereomour build - maybe i’ll follow your example!  I’m planning on keeping the brushed aluminium top plate as is, but could you share as to how you got the mirror finish?

Certainly!  First off, it was a lot of work.  Took some serious trial and error, had to start over multiple times.  I first sanded down the top to remove the machined texturing, started with 180 grit, then 240, 320, then 400.  This step is really important, if you don't get it all the way down, you will see the grooves in your final finish.  I then used a benchtop buffing tool and buffed with Brown Tripoli compound, a good once over the whole plate.  From there, I did a full once over with white diamond buffing compound, then went back around and spot buffed with the white diamond.  After all of that, I polished the top with White Diamond liquid metal polish to finish.  Also had to clean in between each round to remove buffing compound.  Ultimately I am happy with the result, but getting it to a perfect mirror just isn't feasible, the aluminum is very prone to scratching so there are imperfections (even wiping with microfiber can leave visible micro-scratches).  I would only recommend doing it if you have a lot of patience, it definitely tested mine.

[L0rdGwyn]

Added the Mundorf caps and TwoQuiet attenuator.  Here are some pics of the final circuit.

[Paul Joppa]

I know that PB worked hard to make sure there was a ton of room for special caps and other such things - looks like you used up all the space with those Mundorfs! Looks good!

[L0rdGwyn]

I know that PB worked hard to make sure there was a ton of room for special caps and other such things - looks like you used up all the space with those Mundorfs! Looks good!

Thanks Paul!  They just fit, had to change the orientation of two terminals in the TwoQuiet, but hey it works!