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Adventures w/casework have been challenging for me too, but congrats on sticking to it... The results look fine & bet they sound good too.
Sometimes I wish I had a casework/mechanical team I could just pass my work off to Ehh, not really, but the thought crosses my mind when its like 11pm & run into problems...
Anyway I'm leaning toward external PSes now too, seems you eliminate one (more) source of hum in the case. To the point, in one of my SOHA builds I put the transformer & assoc fuse in a cheap case w/a center step-on power switch. So it sits on the floor & you just tap the pushbutton w/your foot.
Used mouser connectors 171-0276 DIN 6 PIN BLACK, 161-0006 6 PIN DIN PANEL MNT < $2 the pair w/some shrink wrap for entry into headamp & 112-R13-40B-R SPST OFF-ON RED < $2. BTW, your connector look massive/military/heavy duty
Have fun,
Chris
Chris, thanks, I apreciate it! After hearing how many do pass their work off to places like front panel express, as well as local machine shops and even carpenters I am strongly considering getting out the yellow pages...
My "foot switch" solution is that the wall wart enclosure is plugged into a power strip and I flick the switch with my foot
The reason I went with the more expensive connectors is that I used those ones you posted a link to on my playstation 1 power supply recasing (I posted a link to the pics a few pages back) and the heat shrink did not adhere very well to the boot. It had too cheap of a feel to me. I bought a generic version from a local shop, but it doesn't look too different. On one side I forgot to slide the boot on first and had to do surgery on it so I wouldn't have to desolder all the pins, but the heatshrink problem happened on both sides. Also, the boot slides off on one side (the one i did correctly) because there is nothing other than a little tab securing it to the metal piece. If I would have filled the boot completely with hot glue, it might have been a little better. But after seeing some of these amphenol connectors, I thought they would be much more "heavy duty" which is exactly what I was looking for. I couldn't even use all the strain relief equipment they send with it, they are built to be waterproof, I believe. I couldn't get the end caps screwed completely down, either due to the way their strain relief/waterproofing mechanisms work. Once I get some better needle nose (either with no threads or wrap some in tape) I will try tightening it down all the way. I am really happy with them though and feel it was worth the price...
nice man, really nice. im nowhere near brave enough or adept enough to try that yet, but one day maybe....again...wow!
Thanks man, I was just happy that it worked, since I found two errors in my layout when I was nearly done soldering. Fortunately they were both in places I hadn't finished soldering yet, because I noticed the connections I was about to make didn't look right.
It's definitely a whole different level of time and effort than just stuffing a PCB, but it wasn't as difficult as I expected and feels a hundred times more rewarding. Just create or copy a circuit you like, get some graph paper, and start drawing a few parts, adding connections, drawing a few more parts, add even more connections, etc. I started with those eight resistors by the output transistors, then worked my way up doing the rest of the output buffer first, then the opamp section, and finally the power section. I'm sure there's an easier way to come up with the layout, but that's how I did it since I've never done this before and don't know any better.
Originally Posted by TzeYang
beautiful work Fitz
I like how you bend the leads to form a bridge instead of using a direct solder bridge. I used to do that alot on my older builds but I thought it would be troublesome to desolder if i need to swap parts. XD
Thanks
I actually clipped the leads short before soldering everything down in one pass, then went back and added the jumpers by pushing them down into the solder until they made contact with the leads and followed up by tacking them down on all the intermediate pads. The pads were spaced too far apart to easily bridge several together with just solder (the surface tension of the solder kept pulling it into two-pad bridges).
Originally Posted by Eokboy
Everythings black... Extreme BoMming there
Maybe even... Too Extreme?
But you wouldn't believe how hard that was! I still gotta replace the silver mica cap with a black one (it's brown, but looks darker in pictures), and order some black connectors to use instead of the white molex KK ones I already have.
Dunno yet, I haven't really thought about it much since I was more concerned with the amp itself working. I'm just running it off my bench supply for the moment.
I made the changes to the original board and hooked everything up with alligator clips just minutes ago, and so far despite the juryrigged setup it still sounds great. Currently listening to the Afterglow Live CD by Sarah McLachlan, which was given to me yesterday as a gift.
I realized used the wrong trimpots for setting the gain when adjusting everything though (works fine, just is more difficult to get it fine-tuned). I'll have to swap those out at some point.
It looks great, particularly like the symmetry on the perfboard. Am I the only one who doesn't know what it is? It looks like a PPA type layout with a chip input and mirror bjt buffer ala ppa. Is there going to be a 3rd channel too? ..dB
It looks great, particularly like the symmetry on the perfboard. Am I the only one who doesn't know what it is? It looks like a PPA type layout with a chip input and mirror bjt buffer ala ppa. Is there going to be a 3rd channel too? ..dB
The symmetry was my biggest goal, as I have a strong belief in balance and harmony, and just putting things in however (even if it led to more efficient use of board space) would've driven me completely insane. That's also why I ended up moving the power caps around (and added the third in the middle, because it looked a little sparse on that end otherwise). I'm glad somebody noticed it.
And yeah, it's pretty much my take on the PPA. I was originally going to just do an ordinary PPAv2, but I was kinda worried about the stability of it when using certain opamps and some headphones. With the changes, I had it wired on breadboard with long wire jumpers out the wahoo, AD843 opamps, and 2 ohm output resistors, and it drove my "amp crusher" 8 ohm test phones to high volumes without oscillating. It would oscillate if I powered up the amp with the test phones connected, but would settle down as soon as I disconnected and reconnected them (it never had any problems with "real" phones in any situation). When I had things closer to a standard PPAv2, I got the same stability issues that some have reported when turning up the volume even on normal headphones, in certain amp configurations. EDIT: Just tested the amp with the "amp crusher" phones now that everything is soldered up nicely, and it no longer oscillates on powerup with them.
I'll probably be building a ground channel too, but I would need to order more parts as some got used up in the left and right channels due to the changes I made after ordering parts.
Although the power supply is still undecided, I do know I'll also be using one of my Alps RK40 Black Beauty pots (not sure if I want to use a detented one or a smooth one), and build a protoboard version of the modified E12 muting / protection circuit I've used in the past, if I can actually remember the changes I made.
Ehh, not really, but the thought crosses my mind when its like 11pm & run into problems...
