Day 7: August 18, 2011
Testing Day with Real Electricity ... AKA, I Was a Naughty Builder!I actually sat down and attempted to go through the testing instructions that Trinity provided with the kit. Things began easy with the bit about plugging in and turning the power on with no tubes (not even a rectifier) plugged in. I measured the two pins getting power form the transformer - basically testing the transformer and not anything I actually did - and got proper readings. So far, so good.
From that point on, either my readings were screwy, I don't know how to take readings or both of my crappy Radio Shack meters are complete garbage! One meter is an old cheapier with a needle gage to read every possible thing on a few different scales. The other is an almost as cheap one with a digital readout - with the addition of black sharpie all over the display courtesy of my three year old.
As I progressed through the instructions (i.e. added the rectifier tube, standby on, then added the other tubes, etc.), I really began scratching my head. My digital meter gives all sorts of weird, crazy values that don't even seem to jive with my old needle meter. This was a quandary. It became instantly clear that I was never going to complete a full table of readings per the instructions using my brain and my two crappy meters. Choices:
1) Ask a billion questions as to what I'm doing wrong
2) Finally break down and buy a decent Fluke or equivalent meter
3) Double check everything again and not worry about 1 and 2.
I was naughty and chose #3. This is my second amp build. The first one fired up perfectly with no mistakes. Since I know I'm crazy anal about not making mistakes with component values or wire locations, and I know I did things right before, I figured I did it right this time. Therefore, I plugged in all the tubes, turned on the power, turned on the standby, and then looked for smoke, melting components or weird noises. When everything looked good, I dialled up the volumes on each channel to listen for noise or hum. Pretty quiet even when cranked (and not even in the shielded cab yet!). Finally a plugged in a guitar and slowly rolled the volume up.
Yikes! It works!
It definitely works, and sounds good, but I'm not sure if it works PROPERLY per design until I get a few questions answered.
1)
Should the sIII's normal (Vol and Tone) channel be louder and brighter than it's 5 knob TMB channel? If so, mine is on the money.
2)
Should the sIII normal channel's Tone control be not nearly as extreme as, for instance, the tone on a guitar? In other words, the tone control definitely rolls off treble, but never gets super dark and woofy - almost sounds like a well-voiced presence control. If so, mine works.
3)
Should the EL84 mode on both channels be somewhat louder (at least at lower volume settings - haven't compared dimed settings yet) than the 6V6 mode? If so, again, mine seems right.
4)
Should the boost be REALLY louder on than off? If so, mine is fine.
Plus, a few non tone/operation questions:
5) I notice the cabinet didn't come with any sheilding for the floor to fully encase the chassis.
Is it worthwhile to glue on some aluminum foil there? Is it "standard" for most builders here? 6) I'm still going to solder the unused power transformer wires to the unused tags on the strip.
But what about the unused output transformer brown and blue wires? The instructions say to tue them off outside the chassis, but how? Right now, I have the ends taped and the wires coiled up. What else? Wire ties? Snip them? Don't snip them? 7) When I go in and put a few wire ties in before closing everything up (and checking those items per the suggestions above), I'm not sure what to do about the coax that goes from the gain to v2. Right now, it's sort of floating about the board given the length and natural stiffness of the cable. Is that good? I don't see a good place to wire tie it unless I choose some components on the board. Is that even a good thing?
Is it better for that wire to be near the board or to be "floating" away from it?
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