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https://i.imgur.com/e4szEU1.jpg
So it pays to group the items together by size:
https://i.imgur.com/Kj78f9J.jpg
Oh noes! I was missing one essential nut. I checked my bike spare parts drawers and found what I needed. This is why you should never throw anything away!
https://i.imgur.com/neo5gkE.jpg
Most of the parts fitted to the chassis:
https://i.imgur.com/cFKw9g8.jpg
The main part of the power supply done:
https://i.imgur.com/3gTkpRL.jpg
Make sure you understand power supply capacitors, bleed resistors etc. Know how to use a multimeter.
Learn a decent soldering technique. For some reason, that’s been a problem with this build, despite investing in a nice station as an upgrade to my trusty 25W Antex. Maybe I should get some lead solder again.
No use now as Barry is taking a sabbatical, but Ampmaker’s build guides are top-notch, full of practical advice that helps you avoid getting stuck in fiddly situations.
That answers the question of why I've never built one.
I keep thinking that I should learn something about electrickery and its various components, but then remember that I've thought that many times over my life, and not got around to it yet!
I’m a two left hands kind of guy when it comes to practice and know just enough to be really wrong about stuff on the theoretical side when it comes to electronics yet still managed to get an SE5A up, running, and sounding great at the very first attempt, and I think that says a lot about both the quality of those guides and the practicality of an average bloke tackling at least a basic amp build.
Remember to take a step forward as the wires tighten up and shorten!
https://i.imgur.com/VO7S7zz.jpg
Got a selection of valves from @karltone to try. Went for the Tung-Sol EL84s:
https://i.imgur.com/5HREHZh.jpg
One good thing about Maplin closing is that I had to look online to buy solder. Hello, my old friend!
https://i.imgur.com/jK7mXLt.jpg
https://i.imgur.com/4au97DZ.jpg
The 12-way rotary switch was... challenging.
https://i.imgur.com/AAmmBok.jpg
I was somewhat surprised to find out it's a 12-way switch? A quick google reveals that a little washer with a tab restricts the movement to any number of positions between 2 and 12. Surprising that this isn't mentioned in the otherwise excellent build guide.
But I run into a more serious problem:
https://i.imgur.com/DdoLSPv.jpg
The locating tab on the switch doesn't line up with the hole. I think the build guide mentions bending the locating tabs back on the pots, and the tabs on the toggle switches line up ok, so this is surprising. I can either file off the tab, or undo everything off the front panel and enlarge the hole with a dremel...
However, when I was wiring up the input sockets I had 1M and 100k resistors left. I thought, that makes sense, because one is a higher gain input. But no, they should both be 1M! I'd wired in a 1M on the switch by mistake. I thought I'd have to stop, get a replacement switch and resistors and start again. Luckily I had a spare 1M, so snipped the wrong one off the switch and carefully wired the 100k onto the tags. It's very fiddly at the best of times, but this made it trickier. I somehow succeeded to do a reasonably tidy job, so carried on.
It's a great feeling when you realise you're about to solder your last connection. Having a little break now before I do the final tests.
Still, you’d expect some minor problems assembling anything from a kit with 200+ parts!
There seems to be a problem with the switch. Mute, mutes. SE (single ended) is also silent - this appears to ground the grid of one of the EL84s when testing continuity, but the other doesn't seem to be connected when the amp is powered up. The two push-pull positions seem quite low in volume, and there's a tremolo quality to the note decay. I think maybe the signal from the phase inverter is not getting to one of the EL84s, and this is happening in all three of the non-mute positions. Needs more investigation...