June 4, 201115 yr Does anyone have the part number for the testpoint connectors? I did a search and couldn't find them. Thx Kerry, just noticed this question. I used Mouser 534-11012-R (and presumably 534-11012-. I like them, my only complaint is that they are hard to get exactly centered with respect to each other, as the hole in the PCB is rather large and they sorta float around in the hole... but, that's a minor complaint.
June 4, 201115 yr Thanks - nattonrice also recommended these, but when I looked on digikey they were listed at over $8 and it didn't say it was for a pack of 100. Mousers price is much better at $2.47.
June 4, 201115 yr Yeah the mouser ones are much cheaper but I had a massive dk order at the time and it was cheaper to throw them on there. I don't remember them being that expensive though, wow. Edited June 4, 201115 yr by nattonrice
June 5, 201115 yr Author Slow and steady progress here. Better red than dead... A rather tight fit but having full loop through capability plus SE/XLR inputs makes it all worth it.
June 6, 201115 yr Author I thought about getting some tanatalums for that spot just to be a bit silly.
June 6, 201115 yr nice! With your loop, won't you have the input RC filter from the amp transferred to the other input? I would think this would have some unintended consequences... I think it's worthwhile to move the feedback resistor like Craig did. I noticed Kevin did this in the second board revision, so I'd assume that he would agree. If you don't have a scope, I'd also add the additional 5pF/1kV caps across the 100K resistors as well (IIRC, Craig ended up omitting these caps and the 2.2pF caps, but I wouldn't do this unless you can verify the results, including transient response). I'm not sure if Craig ever posted picture of the modification, but it's not too hard to imagine what he did. Also, has anyone else done the mod outlined below? If so, I'd be curious to see what your thoughts are. https://picasaweb.google.com/inuponken/T2#5566996623938911634 Edited June 6, 201115 yr by luvdunhill
June 6, 201115 yr Author Any loop coonection will have issues but I think they aren't big enough to outweigh the benefits for my needs. Kevin did change the layout but on his advice I kept the amp as it is at least for now.
June 6, 201115 yr Personally, I'd file Kevin's T2 build with his KGSS build, as a "special" one that doesn't require additional changes and then turn around and do the modifications to stabilize your build.
June 12, 201115 yr ok, one more question that probably nobody cares about, but hey... Would it have been possible to locate the Stax jack and the hole for the volume shaft at the same vertical position? If the jack is about 1.125" tall and the RK50 is 27mm off the PCB, this looks like it should be possible. I'm trying to figure out why this wasn't done... to potentially avoid a mistake cutting my front panel I'm staring at the missing front panel on mine and it looks doable, but I'm not sure if I'm missing something. Edited June 12, 201115 yr by luvdunhill
June 12, 201115 yr the stax jacks were aligned to the inside edge of the extrusion. you should be able to move the jacks down but i'm not going to take mine apart to make sure.
June 12, 201115 yr I've recently bought myself some 2SK216 and 2SJ79 from pacific semi. I'm wondering if these are real or counterfeit since it is lacking the round dimple on the front that most genuine devices seem to have. The edge of the plastic casing is also sharp, not smooth. What do you guys think?
June 12, 201115 yr Author Some progress today, now I just need to finish wiring the PSU and it is ready for testing: I also dared to mess with the one off titanium knob Kevin gave me. I needed some indicator on it so it took about 10 minutes of very careful drilling to come up with this:
June 12, 201115 yr Some progress today, now I just need to finish wiring the PSU and it is ready for testing: I also dared to mess with the one off titanium knob Kevin gave me. I needed some indicator on it so it took about 10 minutes of very careful drilling to come up with this: nice! what's that massive green with yellow stripe wire for? Have you flipped it on yet? Edited June 12, 201115 yr by luvdunhill
June 12, 201115 yr nice! what's that massive green with yellow stripe wire for? Have you flipped it on yet? It lets the bass out.
June 13, 201115 yr Looking good. I got the amp board soldered up and de-fluxed before I mounted anything to the top. I centered all the POTs before soldering them in. Just about to put in the 9 pin sockets. Should they be seated all the way down? If I do that they will sit at a lower height than the octal sockets. I vaguely remember something early in the thread about this, but couldn't find it.
June 13, 201115 yr I enlarged the center hole for the input tube sockets to improve the fit. In looking at various pics, not everyone did this (did anyone?), so it's probably a personal preference. Regardless of what you do, they sit at a lower height than the output tubes. Don't forget to really tighten the center pin before soldering to make sure the two halves of the socket are firmly connected together. Edited June 13, 201115 yr by luvdunhill
June 13, 201115 yr Author nice! what's that massive green with yellow stripe wire for? Have you flipped it on yet? Those are the chassis ground wires, one per umbilical. Better safe than sorry so it is 16AWG. Craig might recognize the wire since it comes from a Russ Andrews cable I was given. If I have time today then I'll finish the PSU and start testing.
June 13, 201115 yr There is at least 2 different kinds of the input tube sockets. On the ones i used, the center pin had no bushing, and fit thru the board completely just fine. You put the 8 pin sockets in as far as they can go. On the 9 pin sockets you align them so that they barely fit thru the circuit board. Then the top of the octals and the 9 pins are close to the same height.
June 15, 201115 yr Getting there Here's a couple of shots of the Amp. I'm going to solder the XLR connectors after I mount them in the chassis. I'll likely do the same with the POT. Here's the underside. Lots of red drops... Here's the top... and here's the 5pF bypass caps on the 100K feedback resistors... That was a bit of a marathon Next up all the power connections and umbilical cords. Edited June 15, 201115 yr by Kerry
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