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Post by Johnkenn on Jun 3, 2016 10:15:15 GMT -6
Yeah...have to say, at first I kinda liked the look of the old ones...now I'm starting to prefer the new look. Also think the new knobs are much easier to use...
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Post by kilroyrock on Jun 3, 2016 12:55:52 GMT -6
the knobs are awesome! the whole pre is SO heavy. question - did you have double sided tape for the input tranny or did you just solder it to the board?
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Post by winetree on Jun 3, 2016 13:29:57 GMT -6
So - here's the update. Jeff got her going! And it wasn't my shitty build!! Jeff can correct me if I'm not describing this correctly, but it ended up being a short to ground on the trace right after the Fader. It was the little hole that sends the output of the fader to the HPF. Jeff drilled out the top and lo and behold...I'm ready to build some more! I've got an older Pair that I haven't tested yet. Is that short to ground on all the VP28 P.S.B.s, or on just a certain run of the boards?
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Post by Johnkenn on Jun 3, 2016 16:20:32 GMT -6
Actually, just my specific one. I think he said this is like the first time this has happened. jsteiger might be able to shed some light
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Post by jsteiger on Jun 3, 2016 16:22:11 GMT -6
As John pointed out, this is the one and only board that I know of like this.
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Post by kilroyrock on Jun 9, 2016 5:44:42 GMT -6
I was able to do 4 2520 DOA's in 4 1/2 hours last night. Could have been 4 but I didn't realize the pcb had been updated until after I'd already twisted and soldered 2 of the diodes together. I am severely hindered on my desoldering techniques, even with my solder sucker and solder braid. It is still a pain in the ass on these small holed doa pcb's.
On a positive note, the new instructions/build order/pcb made it much quicker to blast through them. And by blast through them I mean spend the entire night working on them! Glad that part's done though!
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Post by Guitar on Jun 9, 2016 7:07:25 GMT -6
kilroyrock that's something else! I usually get exhausted after doing only one or two.
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Post by kilroyrock on Jun 9, 2016 7:13:47 GMT -6
kilroyrock that's something else! I usually get exhausted after doing only one or two. So I basically did groups of components (caps, then diodes etc), pretty much each step on each one like an assembly line. I figure out where it goes on the first, and then the other 3 was really quick to place. I had 4 bowls of components that I cycled through. And some Bulleit Rye to keep me company
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Post by Guitar on Jun 9, 2016 7:43:07 GMT -6
kilroyrock that's something else! I usually get exhausted after doing only one or two. So I basically did groups of components (caps, then diodes etc), pretty much each step on each one like an assembly line. I figure out where it goes on the first, and then the other 3 was really quick to place. I had 4 bowls of components that I cycled through. And some Bulleit Rye to keep me company Sounds like a good time. I've done side by side builds like that before, it does feel efficient.
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Post by NoFilterChuck on Jun 9, 2016 9:11:25 GMT -6
Normally you build from smallest component to largest component, starting with those tiny Diodes on the 2520s.
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Post by kilroyrock on Jun 9, 2016 11:21:45 GMT -6
Normally you build from smallest component to largest component, starting with those tiny Diodes on the 2520s. With these 2520's, the diagram kinda went that way, but it also has you build from one side to the other. There is very little room on that pcb to really work smallest to biggest, it's more like widest to narrowest.
So the caps went in, the diodes went in, the regulators went in, the transistors.. usually resistors would be first when I'm building, but with everything being installed vertically, the resistors feel like you're putting that last extra spatula in your kitchen gadgets bucket from the dishwasher. The opposite of a hotdog in a hallway...
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Post by NoFilterChuck on Jun 9, 2016 19:35:37 GMT -6
Roger that. I have built 20 or 30 of em since i got into DIY. I only remember that i need to budget at least 1 hour per op amp when building em.
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Post by Guitar on Jun 9, 2016 20:18:38 GMT -6
Seems to be almost exactly 1 hour for me too, for a 2520 op amp. The fiddliest bit seems to be the mill max pins. The small components are a little easier but still quite tight with the hands.
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Post by kilroyrock on Jun 9, 2016 21:13:10 GMT -6
I have a little colour op amp module from diyre. I set the pins in, then put the board in then solder top down. Real pimp.
What's even more pimp, is the mojo gods I released when I tried the build. Smoked the 10 ohm pr1 and pr3 out of the gate!
Now I get to go to baynes electronics in towson after work! Party!
Now how do you trouble shoot an op amp?! I hear these transistors can flip over when you're tired and drunk? I guess we'll see!
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Post by NoFilterChuck on Jun 9, 2016 21:43:33 GMT -6
for the millmax pins, just stick them in the sockets on the main PCB and solder them to the op amp PCB, then remove the op amp PCB to install the rest of the components.
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Post by Guitar on Jun 9, 2016 21:49:50 GMT -6
I put one of the power transistors in backwards once like a dummy. I flipped it around and it seems to work, but I marked it with pink paint to notice my mistake. XD
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Post by kilroyrock on Jun 10, 2016 5:36:00 GMT -6
I meant to look this morning, because I was too annoyed to troubleshoot it while my buddy was over, and didn't see the thread on this on RGO from 2013, which leads me to believe this is the case. I didn't even look, as I thought they were the same thing for both.. ha! My Q2 op amp though is still money!
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