S.E.X. build

[ALL212]

This is my 6th BH kit build and other than blowing the C4s board with a bad tube I think it went pretty well (after some troubleshooting).  Each picture is after a session with the iron.

The naked top - not much here.  I did use cotton wrapped 20g wire that I found at New Old Sounds.  Cardas input's and I had a set of speaker terminals from Parts Express hanging around that I used.  In order to use the Cardas I had to drill the holes a bit bigger with a stepping bit and also had to add notches to the speaker terminal holes for those posts.


More cloth wrapped wire.


Impedance kit streamed in during the build. I later changed the cotton wrapped wire on 5 and 10 to Mogami.  Alps Blue volume Pot.


Input wiring - Mogami wire used here also.


And the last night.  I worked too late into the night on all this and forgot to put in the C1 to C4 wire and also found some unsoldered connections.
Power supply caps are Nichicon PW, the blue caps are the new Nichicon KA's (used in the Quicksand) and I used Mundorf Supreme's for the 1.5 and .5 caps.  I had to position the power supply caps a bit differently but it all fits.  I did put in the 100r resistors (2w) over the heater at C1, C2 to C3.  I used a Teflon silver coated copper wire to the speaker terminals and impedance boards.  That drill technique for twisting worked perfectly on that wire.


Here's another of the bottom.


Cherry case with some heavier stain, then 5 or 6 coats of tung oil.


Another great kit Bottlehead folks!  Thank you.

 

[mcandmar]

Nice build, so what are you driving with it, speakers or headphones?

 

[ALL212]

Just lit up the HD650's so I have all of 5 minutes on those - but very nice.

My test speakers are rebuilt Dahlquist DQ-10's.  Now, you might think there isn't much sound coming out of them being driven by this amp however, it's amazing what volume level you can get them to.  More than enough to enjoy - volume at around the 1 o'clock position.

More minutes on the HD650's - dead quiet background.  This analogy might seem a bit strange but I'm a network admin and live in the pc world everyday.  The "resolution" of this is amazing - it's like having a computer monitor dialed in so that you see every tiny dot on the screen and everything is in tight focus.

;D ;D ;D ;D

 

[mcandmar]

You mean its like an old school Mitsubishi Diamondtron monitor perfectly calibrated and not one of these boxy pixel flat screen interpretations with limited colour range?  I know exactly where you are coming from

 

[JamieMcC]

Nice job and as I've just started my own Sex build the neatness of you build is inspiring me to try and achieve similar results.

 

[Grainger49]

Really beautiful work, both on the SEX itself and the base.

 

[Chris65]

Nice work! Are those tube sockets standard or modified in some way?

 

[ALL212]

Nice work! Are those tube sockets standard or modified in some way?

Standard modified sockets!  Bottlehead ships some O-rings to put around them.  No deviation there from the printed plans.

I've got a hum (60 cycle I think?) in one channel that I can "fix" by pulling up on the volume knob so I think I probably overheated something in that pot.  Wiring in that area with the cable I used was very tight so I'm going to rethink that.  One thing I did find is that you can use the headphone ground connection (goes from one side all the way through to the other at the base of the headphone jack) as a ground bar for other connections at that point rather than have to try and use the terminals themselves.  That goes for the ground wire coming from the C4s also.

A thought - this is my first build with the Mundorf caps.  Are they really that good?  Prior to this I've used Sonicap or Clarity caps.

Because of the smallness of the caps (.5 and 1.5) the cost is fairly low. I'm wondering if I can build something that will allow me to switch caps in and out easily.  Because of the headphone connection this would allow some very nice cap comparisons.

I used Mogami Neglex 2534 from input to pot (the green cable).  It has two pair and a shield.  I then used Mogami Neglex 2549 in other areas as it is one pair (blue and red cables).  It's hard to use that near the volume pot - there's not much room in there.

 

[ALL212]

Addendum:
I had a hum - no one knew the words  - and at first I thought it was the volume pot (alps blue) but after I ordered a replacement I'm pretty sure I found it to be the headphone jack so...
I put in a Goldpoint attenuator and a new headphone jack.  Now I cannot get anyone to hum for me!  That attenuator is a bit of an extravagance for me but it is so much easier to install than the Alps.  The headphone jack is just one model up from the stock in the Neutrik line.  It's got a chrome top and the connectors are a bit longer (easier to work with by just a bit).

A bit of panic when I first lit it up - I didn't have the DAC turned on and I couldn't figure out why I had no sound.. :

Still waiting for the replacement C4s but wiring is in place and it should be a quick and painless install.

 

[i luvmusic 2]

Those MOGAMI Wires are they rated for High Voltage and high temperature?

 

[ALL212]

Not sure about high volts as they are 24 gauge each.  High temp - it holds its shape when soldering but let's just skip to the fun.  Here's the specs from Mogami:

http://www.mogamicable.com/category/bulk/microphone/quad/

http://www.mogamicable.com/category/bulk/microphone/quality_balanced/

The very light blue wire at the attenuator is Cardas 2x24.  It's much smaller and flexible but a real pain to work with so I don't use it much.  It has two PTFE tape wraps and one "semi-conductive" tape wrap in addition to the shield wire that is a very tiny gauge and is easy to cut through.  The wires are also enameled so you have to tin them very well before use.

I've used the Mogami W2534 for interconnects and speaker wire by combining the pairs or all 4 wires into one.  I don't use those on my high powered amps but on the bottlehead equipment it works wonders.  8)

The W2534 makes  a fantastic replacement to the stock Sennheiser headphone cables.  If you don't think cables make a difference there's one place that will amaze you.
.

 

[i luvmusic 2]

Thank You! for the link...

 

[Grainger49]

There are standard insulation ranges.  Low voltage is 300V, we used it for instrumentation and control wires.  There is also a 600V rating we used for 480V 3 phase.  5kV and 13kV distribution, of course, had higher rated insulation.

All hookup wire you will find most places is rated for 300V but has no problem with the 450V DC you might come across in Bottlehead kits.

 

[i luvmusic 2]

Thank You!