I bought a Crack off ebay some time ago, pre-built.  It came with AΞON output capacitors.  I've since replaced the RCAs with Neutrik ones and the headphone jack with a Neutrik latching jawn.  The octal tube socket just plain sucks and the signal started becoming intermittent, so I took the amp out of commission and I am going to do a whole slew of things to it.

• I ordered new tube sockets.  They are the teflon composite type from Parts Connexion.  They have a silver-plated crown springs inside the contacts made of beryllium copper.
• The capacitors came dangling.  I just used packing tape to keep them held up.  It works and can't easily be seen because it's clear.  It's not ideal so I designed some brackets in SketchUp and are having them made at shapeways for $3.96 apiece.  They made specifically for my capacitors, and you can see the slots for the zip tie.  Click this sentence to visit the site and maybe purchase them. I don't get anything for it.  I designed them and put them up for everybody.
• The headphone jack is crooked and could use some mounting work.  I am going to look for a machinist to just nip into the top plate a tiny bit to the shape of the jack's flange so it absolutely will not move.
• I am replacing all hardware with torx hardware.  I haven't found a place where I can get all the same alloy for all of the sizes I need and inexpensive.  McMaster-Carr has them all for cheap, but in different alloys.  Aaron's has any size you can imagine and in whatever alloy you want, but small quantities are expensive.  I would maybe go for larger quantities if people would go in on a buy (hint hint).  Fastenal doesn't really have anything, anymore.
• I am going to have the top plate and transformer end bell powder coated.
• I am looking to add in an audio spectrum analyzer circuit I bought some time ago.  I would like it to be after the volume control.  Will there be any impedance problems?
• I am looking to add a timed relay circuit that won't connect the headphone output at power on until a set amount of time.
• The Speedball upgrade will be done.  What hardware does that kit use?  If I have excess quantities from the bulk I order for the Crack itself it would be nice to have these used for mounting the Speedball.
• I am thinking about solid silver wire with cloth insulation, and not with PVC or teflon innards.  Does anyone know of a place that sells a decent selection of sizes and colors (red, white, and black)?  I found a place in the UK, but I would prefer somewhere in North America.

So far I'm impressed with the amp.  I didn't think the sound would change that much from the on-board amp on my STX card.  Naysayers obviously don't understand that impedance is only measured at one frequency point and high-impedance headphones like my HD-650s are quite demanding of power for bass.  You need a healthy reserve of power to drive low frequencies. More Updates to come.