DIY speaker switch with headphone out

I don't know if this project deserves it's own thread, but things have been a little slow around here and I took pictures of the build, so I'm posting it.

Here is the use case:

My old Scott tube integrated has multiple speaker taps and 2 sets of grounds, but when I tried a simplified switch box using both the 8 and 16ohm taps the amp was unhappy. So the goal of this box was to use the single pair of 16ohm taps and make them work with my 16ohm Altecs, 8ohm desktop speakers, and a convenient headphone jack for my ESX900's.

"Design"
I'm using some generic amazon 8ohm 50W resistors in series with the 8ohm speakers as a power soak to match the 16ohm output tap. Since the 8ohm desktop speakers are single driver with no crossover the resistor doesn't really interfere with the frequency response. It's possible there's a slight bass boost but I'm ok with it on smallish single driver speakers anyway. I'm using a voltage divider with an equivalent resistance of about 32ohms for the HP jack. The voltage divider is made up of 1x 33ohm 3W resistor in series with the positive side of each channel and a 10ohm 3W resistor after the series resistor across from the positive to negative side of each channel. It's pretty much the same setup Scott uses from the internal 16ohm tap for the headphone out on the 222C/D. There's a separate DPST on/off switch for each output. I could have been accomplished with a rotary switch, but the wiring would have been more of a pain in the ass, and I was able to get 3x high quality silver contact DPST switches for about half the price of a nice rotary switch. If I was doing it again I would probably either bite the bullet and get a fancy Elma rotary switch or 3x 4PST switches for isolated grounds, but so far I haven't noticed any signal deterioration from the box.

You can buy a commercial product for about the cost of parts, or less, but the cheap one I bought on amazon sucked even after removing the PCB and hand wiring the connections. Anyway, I like to make things and I wanted to choose decent components and add an HP jack so I built one. Here's the parts list:

NKK S331 DPST switches x3
Hammond 1455U1601 enclosure x1
3 pole solder lug terminals x2
6 pole solder lug terminal x1
Vishay/Dale 33ohm/3W 1% metal film resistors x2
Vishay/Dale 10ohm/3W 1% metal film resistors x2
Generic amazon 8ohm wire wound aluminum enclosure power resistors x2
Generic amazon gold plated copper 5 way binding post pairs x6
Switchcraft 12BW07 panel mount 1/4" stereo jack x1
Generic amazon rubber feet x4

Later in the build I decided I didn't really trust the insulation on the binding posts so I ordered plastic face plates for the aluminum Hammond enclosure- they were Hammond part # 1455UPLBK

First off I drilled the holes for the rubber feet to give the enclosure some clearance above the bench surface while working:


I used a flat needle file to remove the burrs from the opposite side:


And feet mounted:


Rough parts layout:


Measuring, drilling, and test fitting the front panel components(a small carbide drill bit and good quality step bit are very useful here):


Front panel test fit:


Measuring/drilling/test fitting/installing rear panel binding posts:




Drill holes and mount solder lug terminals and power resistors:



Fail to take pictures of the remaining process until it's all wired up and faceplates have been switched to plastic:


Finished box on the desk:


There's a pretty direct signal path for the Altecs, which are my main concern, but the desktop speakers sound pretty much unchanged from a direct 8ohm connection save for needing to turn the volume up a little higher. The HP jack has a low level hum, but so do the sensitive Altecs, just part of a vintage tube amp. The hum volume doesn't increase with amp volume and is never noticeable when music is playing so I'm fine with it.