I wanted to put in a word for the Allo Volt +. I've had mine for about 3 weeks and am very pleased with the sound and the build quality. I've had Western Electric 300B tube amps, gain clones, and several of Arjen Van Helder's Tripath 2020's, along with the Hifimediy t2. The 300B's definitely had more body, but I clearly prefer the Volt+ to any of the others.
At low volume with my Scanspeak two ways, the volt+ sounds sweet detailed and full. I'm currently using a 19 volt 4.5 amp laptop power supply and it's fine to medium volume with my high 80's DB efficiency speakers. At higher volumes, I do think some combination of distortion and sheer lack of power become more of an issue. The amp still sounds good, but a lot less magical. It's very similar to older tubed amps at high volume. You notice the bass notes sound too rounded and lack much of an attack.
That said, the Volt+ is $42 delivered, a terrific value. The Breeze Audio doesn't have the same level of transparency and it could easily cost me that much in parts to get it to the level of the Volt +. For under $25 delivered. It has the advantage of being in a case. I currently have it hooked up to our television with a pair of Radio Shack LX5's. IT's great for that sort of application or for doing Spotify/Pandora. The Volt+ is good enough for serious low-level listening. In fact, it's as good at low volumes as any amplifier I've ever heard. They don't quite have that quality of the 300B's of your almost being unaware that the sound is amplified at all, but it's close and they have the advantage of better treble extension.
At low volume with my Scanspeak two ways, the volt+ sounds sweet detailed and full. I'm currently using a 19 volt 4.5 amp laptop power supply and it's fine to medium volume with my high 80's DB efficiency speakers. At higher volumes, I do think some combination of distortion and sheer lack of power become more of an issue. The amp still sounds good, but a lot less magical. It's very similar to older tubed amps at high volume. You notice the bass notes sound too rounded and lack much of an attack.
That said, the Volt+ is $42 delivered, a terrific value. The Breeze Audio doesn't have the same level of transparency and it could easily cost me that much in parts to get it to the level of the Volt +. For under $25 delivered. It has the advantage of being in a case. I currently have it hooked up to our television with a pair of Radio Shack LX5's. IT's great for that sort of application or for doing Spotify/Pandora. The Volt+ is good enough for serious low-level listening. In fact, it's as good at low volumes as any amplifier I've ever heard. They don't quite have that quality of the 300B's of your almost being unaware that the sound is amplified at all, but it's close and they have the advantage of better treble extension.
K1/K2 = 108dB.I have put a linear PSU now. The improvement in sound has been substantial, as the switching noise isn't there.
Please educate me, since I am not an electronics grad.
Where is the switching noise generated in a trafo- bridge rectifier - capacitor chain of a LPSU?
Earlier you told how your 3116 board was clearly preferred above volt+. Seems like you even hear increased musicality now with LPSU.
Strange Forest of Noise with Linear PSU
Strange Forest of Noise with Linear PSU
Based on the 1.5mm L of the resistors, they are Code 603/1608 with a power rating of 1/10W. Looking forward to popping them in
.
Cheers,
pcb's are available at present. BOM costs at Mouser are at ~$38 per board due to choosen components like i.e. flex/softterm caps.
Inductors are ~$6
TPA3128 ~$4.20
Bulk caps ~ $3.60
Without using any connectors i'd think you can reduce the costs by ~$5-8 per board.
They're up and running. 
TPA3128D2 Matchbox sized class-d amplifier - YouTube
Crimping JST-SH 1.00mm connectors is really pita, i wouldn't recommend.
Right before they went to reflow:
Solderpaste came out a bit uneven as i tried a paper made stencil for the first time. But all went good, will post a money shoot later.
TPA3128D2 Matchbox sized class-d amplifier - YouTube
Crimping JST-SH 1.00mm connectors is really pita, i wouldn't recommend.
Right before they went to reflow:
Solderpaste came out a bit uneven as i tried a paper made stencil for the first time. But all went good, will post a money shoot later.
Attachments
Those three pins with the solder blob on them are the three frequency selection pins (AM0-2), or "AM avoidance", according to the datasheet.
Since the "111" (ie. all three pulled high) is "reserved", according to the datasheet, that's most likely "000" (all pulled low, to ground), which sets the oscillator to 400kHz.
Since the "111" (ie. all three pulled high) is "reserved", according to the datasheet, that's most likely "000" (all pulled low, to ground), which sets the oscillator to 400kHz.