The DIY/Projects Thread

BoilerRhapsody

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I pretty much only post about music here, so none of you would know I was an electronics technician. While I've never been much of an audiophile hobbyist I did get through a pretty substantial project, as apprentices a colleague and I made a pretty serious amplifier:

Overview.jpg

Its a bit of a beast: 200+ hours of work, it weighs about 65 Kilograms (~145 pounds), and while we've never fully stretched its legs we were shooting for 1000W audio output (I think we got close).

Front Panel.jpg

The chassis is from some old piece of test equipment, I machined this front panel myself (including milling the fan vent) which is solid Aluminium, with Aluminium knobs and nice industrial looking exposed fasteners. The knobs control main volume, sub channel crossover frequency, cooling fan speed, and something else (sub channel volume maybe?)

Transformers.jpg

These ridiculously over the top transformers provide the vast majority of the weight, and all that power.

PCBs.jpg

The actual amplification bits are Silicon Chip kits, so we never got way deep into the grittiness of designing amplification circuits and PCBs. The potential 1000W output is split across 2 channels, which are split between D-Class sub amps and AB Class for the rest of the frequencies. So in the photo, you can see each channel is on one side, with 12V power supply boards upside down on top, then the ABs below, then the Ds at the bottom. Those two pale boards in the middle handle speaker protection, and the crossover to make sure the low frequencies go into the sub amps and the rest into the normal amps. Those are sitting on a large central heatsink tube with a fan at each end, which is where all the heat from the amps goes and is blasted out the front through that grille I spent way too much time machining. That thing at the bottom of the photo is a scroll fan that was sitting around and looks cool, so we put it in there for some 'ambient' airflow.

Power Supply.jpg

Just some detail, that little board on the left is another 12V power supply, for the fans. You can also see one of the solid brass blocks that holds the front panel on, which is another ridiculous over the top solution, but that was what made this fun. You can also see that single little regulator on the power supply attached to one of those giant heatsinks that run along the sides of the chassis, that is literally all they get used for which is a shame because they are impressive heatsinks, essentially being huge chunks of solid copper, but we couldn't figure out a good layout for all the amps that got to use them so they're pretty much just aesthetic (and heavy!).

It really needs a pre-amp, which we never got around to installing, so without that and only testing one channel at a time from memory we got 350 Watts out of it, so when it was all lit up at the many parties it served us, we were probably bumping 700-800 Watts out into the neighborhood (in a couple of the photos you can see its sitting on a custom sub box we made, which had 4 12 inch subs and proper porting and stuff, they go well together). The bonus hidden feature is that when the cops show up and claim they're going to confiscate it, you can just tell them go right ahead because they wont be able to carry it out, aside from being way too heavy, the handles are very uncomfortable, and the weight is extremely off center, so it is a massive pain to move it anywhere.

Anyone into the electronics side of things? I don't think I've ever seen anyone talk about DIY audio here before, it would be cool to see any projects you have.
 
I made this Amp Camp Amp this past winter. It's a kit with everything you need, minus the appropriate tools (soldering iron, digital multi meter, various wire cutters, small screwdriver) all for $375 shipped. It's an 8 watts per channel pure class A amp designed by amplifier legend Nelson Pass (Pass Labs, First Watt). It's sounds fantastic and is great with high efficiency speakers. I currently use it to drive 90 db @ 6ohm Wharfedale floorstanding speakers. I have a pair of Zu Audio Dirty Weekend speakers 97db @ 12 ohm arriving next week which should both be a better fit and perhaps a better test of how good the amp really sounds. In any event, $375 is a nice price to dabble in DIY audio. I had never soldered anything before and it fired up on the first try, so I encourage anyone else considering a DIY project to go for it. Great, clear directions available as well. Some day it will be an overqualified 2nd or 3rd system amp as I upgrade components over time.20190212_205516.jpg20190213_135953.jpg20190213_145839.jpg20190215_131210.jpg20190215_131221.jpg20190215_145153.jpg
 
I made this Amp Camp Amp this past winter. It's a kit with everything you need, minus the appropriate tools (soldering iron, digital multi meter, various wire cutters, small screwdriver) all for $375 shipped. It's an 8 watts per channel pure class A amp designed by amplifier legend Nelson Pass (Pass Labs, First Watt). It's sounds fantastic and is great with high efficiency speakers. I currently use it to drive 90 db @ 6ohm Wharfedale floorstanding speakers. I have a pair of Zu Audio Dirty Weekend speakers 97db @ 12 ohm arriving next week which should both be a better fit and perhaps a better test of how good the amp really sounds. In any event, $375 is a nice price to dabble in DIY audio. I had never soldered anything before and it fired up on the first try, so I encourage anyone else considering a DIY project to go for it. Great, clear directions available as well. Some day it will be an overqualified 2nd or 3rd system amp as I upgrade components over time.View attachment 6107View attachment 6108View attachment 6109View attachment 6111View attachment 6113View attachment 6114

Neat! Looks great, a lot nicer than two apprentices cobbling together multiple kits and whatever they could find for free in a workshop. Highly likely much higher audio quality out of something like this too, we were never bothered to test the fidelity of ours.
Hard to tell from the pictures, but the soldering looks pretty nice too.
 
Pretty effusive praise for the DIY Amp Camp Amp I used to have in my primary system (see pics further above).
 
I recently acquired a Technics SP-10 mk2, which became a fun DIY project.

Thus far, I've:
  • Built a new plinth using baltic birch ply, then covered it in rosewood and finished it with Waterlox
  • Replaced the electrolytic caps within the turntable unit
  • Configured the speed control (which also involved learning how to take measurements with an oscilloscope)
  • Cut the armboard
I'm nearly done, but I still plan to:
  • Drill holes in the bottom and epoxy in lead shot to increase the mass of the turntable. I'm aiming for a total weight around 50 lbs.
  • Rub the plinth down to satin after the finish cures
  • Install the tonearm and set VTA/VTF/azimuth/alignment
  • Listen to records!
 
Do you still have this amp? How do you like it now? What are you using it with (if you still have it)?
I still have it, but it's not hooked up to anything at the moment. For what it is, I think it's great. It has a really sweet warm tone, but lacks muscle, given it has 8 watts and lacks a power transformer. I do swap it in now and again just for fun.

I think if a person had a Subwoofer in their system, it could be a great bargain solution with a pair of efficient speakers

It did sell me on Pass/First Watt amps as future options, as those would have that additional power and control that my little amp lacks, and still bring the Nelson Pass magic.
 
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I still have it, but it's not hooked up to anything at the moment. For what it is, I think it's great. It has a really sweet warm tone, but lacks muscle, given it has 8 watts and lacks a power transformer. I do swap it in now and again just for fun.

I think if a person had a Subwoofer in their system, it could be a great bargain solution with a pair of efficient speakers

It did sell me on Pass/First Watt amps as future options, as those would have that additional power and control that my little amp lacks, and still bring the Nelson Pass magic.
Thanks for the update. It looks like a fun project, but I was curious if it actually turned into a main component in your system or, as you describe, became something that mainly piqued interest in their top dollar amps.
 
Thanks for the update. It looks like a fun project, but I was curious if it actually turned into a main component in your system or, as you describe, became something that mainly piqued interest in their top dollar amps.
Ah. Yes, it was my main amp for about 9 months or so. It drove the Zu Dirty Weekends I had at the time. Prior to that I had been using the 50 watt/ch Marantz NR1606, an AVR amp. It sounded soooo much better than the Marantz, that I was happy to lose the bass oomph in favor of the overall sound.

I eventually found a deal on my current PrimaLuna amp, and at 36 watts of tube power, the little amp can't compete. I will say the pure tone of the amp camp amp is better to my ears than the PrimaLuna. That's what got me eyeballing the bigger Pass stuff.

It was a fun project and pretty easy. I had never done any soldering before and know zilch about amp circuits. It fired up and worked the first time, amazingly. I might do another one and Monoblock them someday. It was really interesting how different they sounded to Guttenberg as monoblocks vs a single stereo amp.

You've got me wanting to swap it back in for a little while again!
 
I recently acquired a Technics SP-10 mk2, which became a fun DIY project.

Thus far, I've:
  • Built a new plinth using baltic birch ply, then covered it in rosewood and finished it with Waterlox
  • Replaced the electrolytic caps within the turntable unit
  • Configured the speed control (which also involved learning how to take measurements with an oscilloscope)
  • Cut the armboard
I'm nearly done, but I still plan to:
  • Drill holes in the bottom and epoxy in lead shot to increase the mass of the turntable. I'm aiming for a total weight around 50 lbs.
  • Rub the plinth down to satin after the finish cures
  • Install the tonearm and set VTA/VTF/azimuth/alignment
  • Listen to records!
Pictures please!
 
Maybe folks already know about this site, but I recently discovered it and it’s a great diy resource.

Here’s a pretty comprehensive set of audio reviews for capacitors.
The Humble site is a great resource and my own tests generally agree with its assessments.

Something I do is a straight wire bypass test. DC coupled preamp, DC coupled power amp and wire the capacitor under test into the interconnect cable between pre and power amp. Its easy and instantaneous to jumper the capacitor leaving just the straight wire. While not exactly the same as having voltage on the cap when used in tube gear or as a loudspeaker crossover component, it does give a sense of what the capacitor does vs not being there at all. Straight wire bypass test is more useful to me vs a description of it's sound "with the acme 2000 cap violins float on the wings of angels..." etc.

There is a lot of mythology with caps (as with much of audio) but the bypass test takes no prisoners and you realize instantly what you lose with a cap in the signal path. My quicksilver phono pre has on its main output ClarityCap MR paralleled with Mundorf Supreme SGO both bypassed with a tiny V-Cap CuTF. That combo is really close to a piece of wire. Not exact, but close.

Without the Humble site I wouldnt have even known where to start.

Pat
 
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