Update Dec 5 2020: GT5 Plans (TB and TMB models) now available@: www.elamscafeb... If you would like to download the plans, visit elamscafe.com/... Mark II Version now available in comprehensive Full Plans Pack.
Beautiful workmanship! I appreciate the way you kept the filament supply running hard against the chassis. I may have missed it, but it could benefit your viewers to explain why this is important, along with the twisting. You deserve the Double Gold star for terminating your pushback wire with heatshrink. Excellent build.
Thanks TGAT! Really appreciate the kind words. I'm about to build the addition to this wee amp, that is, same amp with TB tone stack. Ill certainly go into the theory a bit more. Cheers!!
Thank you for this most excellent video. Best job of filming, clear explanation, and useful information I've seen. There are close-ups and very clear explanations. Thank you for sharing your knowledge and experience.
I thought the bug was actually crawling across my monitor. Thanks for pointing it out before I began swatting the screen. Also... your wooden mallet looks like a gnarly murder weapon. \m/ Awesome video Bud!
Beautiful work. Super neat. Your filament wires on V2 may be unnecessarily twisted. Because there are the same AC voltage, there is no advantage to twisting.
Looking very nice. I like these boards. I would advise you to raise the filament wires from the chassis. Laying them on the chassis can introduce hum. Best is to let these float in the air, a few centimeters from the chassis, towards the tube and then bend them 90 degrees downwards to the tube.
I love your technique and attention to detail. I'm curious: Why do you keep the heaters close to the chassis? It seems like flying them downward toward the tube socket could induce less noise from AC heaters. I haven't A/B'd these techniques, however, and I trust your input on this matter.
Yes indeed you can bring them down from a vertical position and it's a great way to do it. My father does it this way too, every time. I find that heater wires in vertical position gets too busy around the tube socket for my liking. I end up touching the insulation with the iron and for that reason, I like to position the heater wires as far out of harms way as possible. If you can manage heaters in a vertical manner, then that's fantastic. I'd wager it's probably a superior orientation, however if wires are twisted and connected correctly, there would be not too much difference. Cheers.
'Wash your hands before touching this nice white cable' Haha!! And that my friend is why your builds are always a work of art! :O Details like this, that I would never dream of doing. Always good to see you uploading mate :)
Get those small pointed jewelry pliers from hobby store put the point of the pliers into the turret top hole and it will wrap those bare wire ends around the turrets.
I had a leaking floor in my bathroom, and I rent so they came in to replace the floor for free right, and they had to protect my floor in my appartment and they used these mdf plates which they taped on the floor, I asked them afterward whether I could keep the mdf plates, figuring they'd come in handy someday, well
Geoff - really great series so far, I appreciate the work you've put into this. What did you use there for a swaging tool? Just some steel round stock filed to a point, or was it something fancier? Also the stanley drill alignment tool you used in the chassis-building vid -- does it have a name/number?
I use this cable for making my own shielded hookup cable. 22awg tubedepot.com/products/22-ga-tin-plated-aerospace-grade-tefzel-wire-100-feet For all my solid core cable, 20, 18awg, I source from RS online. It is their tinned bus cable. I get it in rolls. I also have a collection of vintage cable I get from local auctions. Cheers
Nah mate, you're doing it wrong. I've seen inside factory made electronics, so I know what's what! The wires have to be formed into a rats nest and then be crammed into the case. Seriously thoough, nice job on this tutorial series.
Nice clean work, does it really make sense, to color en seperate the filament wires in a AC configuration?... so that pins 9 is always has the same wire and so for pins 5 the same?
Thanks. To answer the question, yes it does matter what pins, and how it is twisted.. That is because if you get the pins mixed, you dont get any cancellation. You could rectify the AC, in that way, it would not matter. However with twisting, it absolutely matters. Cheers
elams1894 Thanks a lot, this helps me further in thinking how to prevent ac hum as much as can. In a diagram of an old circuit i'll have to feed the 12ax7 heaters, it shows pin 4 & 5 are connected simply by 1 filament wire to both (like a bridge) and pin 9 got the other, is that something to think about? Cheers mate
I would just make up a bunch of twisted pair with a hand drill or electric screwdriver and forget about polarity for the heaters, aren't they AC anyway?
The drill trick is a good one, I've never used it for solid core, and I'm not sure why now actually come to think of it. The heaters are ac however I believe opposite sides of the secondary winding need to be twisted to get hum cancelling. If the same sides of the winding are twisted there is no hum cancelling. I'm still trying to figure out current flow in my head as a result of my first configuration. AC theory is a tricky one indeed.
hey jeff good to see the next installment. i have brought the full pack and have being going through the parts list everything looks ok apart from the transformers is there anything that subtitues the power transformer?
+clint taylor Hi clint, you can use any power transformer that has from about 520-550v secondary or there abouts. Also you need separate 6.3v secondary winding for the filaments as well, but most will have that. If they have more secondary windings, you just terminate them and don't use. The transformer out of an old NZ Bell Colt radio is perfect for this build actually. You just need a 5-10 watt output tranny, if it has the 4, 8, and 16 ohm taps then you are sorted, if only one, then make sure the speaker is the same ohm rating, all good.
+BEAVIS Motorsport I'm not completely sure to be honest, my forefathers always pronounced t swarge so it stuck I guess, however they are Scottish in origin so the jury is out in figuring out that accent ha ha..
Fair enough. I have no interest in a tube amp, but I truly enjoy your intricate work and attention to detail so I find your videos a real treat. I started watching back when you built the carbon gimbal - wow that was a fun watch.
HI! Thanks for making these videos! Question: I would like to build a version of this amp for bass, which mods would I have to make to it in order for it to work well?
I guess for a bass amp, you would prefer a clean signal? If you only require a clean signal you could try and modify the gain stages so that you do not get any distortion. A JTM45 preamp circuit would be the best place to look. Cheers
