So, not much progress at the moment, other than i managed to order some parts (valve sockets, shields, IEC plugs, light, jewel covers to make power light pretty and other gubbins) so I'm not really going to go into that, other than that I have forgotten how to count, and for some reason thought the BE100 used 5 preamp tubes, when it actually only uses 4. So that was dumb, and as a result I'll have a 5th of all those parts. On the bright side, there's a margin for error, like, for instance, if the toolshed elves decide to steal 20% of my preamp parts, I'll have that covered...
This isn't about that, it's more about me having a slight panic. The reason for this is pretty much eh following. On my last (and first) build, there was a ton of docs out there. Boards well defined, loads of layout info, you name it, all there, so it was pretty much paint by numbers once I'd drawn the parts on the printouts of the PCBs.
This time however, less lucky. What I have are some layouts on a rev1 board, some boms, pics of an real BE100 inside, and some variant layouts (to build a JJ, maybe a phil X etc, basically, not sure, as just want to build the BE100 to start with). This would be all good and well, until I today decided to take one of the boards I have, and start soaking in the layout byu looking at what I had and the physical board.
The game of spot the difference (fun when you're a kid, keeps you quiet for ages) quickly turned into "try to spot the similarity" which is less fun when you're looking at a board that say "rev2". Quite a bit is moved, the board have no R or C labels (like r1, r2, r3, c1, c2..c30 etc) which then means either I:
a) time consumingly measure each connection on the board and see where it goes and draw out the board, then compare that to the circuit diagrams, and slowly build it up from that.
b) try to look at the low res .png file of the rev2 board i found buried in the docs, and try and guess what some of the resistor and capacitor names are, as they are usefully in light grey on a white background, and even more usefully sometimes obscured and completely illegable by some kind of whatever.
c) buy another board set
or
d) panic...
The problems are:
a) I'll lose patience, and walk (head down, despondent) down the end of the road to have a conversation about the meaning of life with the goat and donkey who get tortured by visiting kids daily and have obviously accepted their sad lot and given up on the proposed topic of conversation(the donkey makes eeyore (or whatever his name is) look like an optimist). This path means this blog ends for another year whilst I end up doing things that are decisively less time consuming and dull (and frustrating)
b) Just means the above, but in a different form. My eyesight isn't good enough, and more importantly the png isn't high enough res by far, so the labels pixelate before you can get any clues out of them.
c) Too stubborn. Not going to happen. I will prevail, if not today, then hopefully this decade.
d) Well, kind of went there.
Anyway, so I spoke to the oracle (Tony). Decided to follow his advice of contacting the guy that made the boards, see if he has updated docs. Success, apparently tomorrow I should find something better. Even a translation from v1.0->2.0 of the board will do. I can then do some drawing by numbers.
So, in light of all of this, I kind of realized I had not understood the slo circuit when i built the amp and had just been soldering by numbers. I had meant to, but just didn't. And that kind of annoyed me a bit, as it was meant to be a learning experience as well.
What to do? Time to rectify the situation, and bridge the knowledge gap (see what I did there?)
So today I have been refreshing some electronics knowledge, having a look at simple tube based gain stage circuits and just ramming home what each little bit, resistor and cap kind of does on a simple level. Kind of let it soak in. The aim is that after a few days I can look at the BE100 schematic and know what each bit does, be able to break up the stages, understand the tone stack and in general see what I am building, and then hopefully percolate that so I can then know what mods do when I hopefully add some.
So yeah, that's the plan really, just dust off my degree from 21 years ago, become less rusty and start thinking in electronics for a while.
Anyway, point is, I stumbled across the video below, and it really just gave me a "oh, that's cool, I get it" moment I'd been missing. I am working my way through the series and find it well explained. I've also been treating it a bit like a lecture, and been taking notes. I'm currently watch the PSU one. Tomorrow ("it's only a day away" - as sung by the ever optimistic orphan annie) I'll do the push pull section as a refresher, and work my way through them.
So, here's the video, worth a watch if you want a very simple run through of the various bits of a diagram as a start (wasn't my issue) and want a quick primer on a bunch of useful stuff and on the basics of pin out connections, what the load and bias resistors are, coupling caps, some quick other bits and where they live on a diagram. Sometimes it's better to see and hear rather than read.
Anyway, I reckon once I really get my head around the BE100, then the slo circuit gets revisited. Should stop me looking like a bit of a simpleton in front of The Oracle as well. Which would be nice. As asking tons of stupid questions just isn't good for one's ego...
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