I use the s11 in lots of things and it works especially great with these Class D amps. Just know that it's a high-performance design with no compromises and it's easy fry those fat resistors with a momentary short or unfortunate power-up sequence. Have you checked the s11 recently for proper output with/without load? Doesn't really sound like your problem, but maybe worth verifying.
BK
I second this request. I'm looking at finally starting a 6 channel build and would like to dig into what configuration options I can play with (selectable PBTL, selectable SE / BAL input, adjustable gain, etc).
Looking at the silkscreened documentation, it appears that gain adjustments could easily be made off board by selecting between gain resistors. Would it be possible to make PBTL selectable by switching the documented PBTL connections offboard? Could C33 / C34 be moved externally and switched in when not PBTL?
Hey, sorry for falling off the face of the earthToo many other projects going on.
I'm guessing we can all relate to that! Great to hear back and looking forward to the documentation!
Schematic and microcontroller source files are attached. Between the two of them, if the board is doing something odd/unexpected you should be able to use these to diagnose the problem and fix it.
Unfortunately, to reprogram the microcontroller you have to remove it from the board. The ATTiny20 requires +5V to program, and the digital control lines for the TPA can't handle that voltage.
I could do another group buy, but honestly I don't have the time and I really don't want to disappoint people with long lead times like the several months it took to get the last group buy out. I could get a local electronics shop to do the build instead of doing it myself, but there'd be a minimum order quantity of 50 or more required to hit a reasonable price point, and I'd have to settle on one type of board (stereo or Pro) versus 3 different types. Given enough interest I'll do it.
Unfortunately, to reprogram the microcontroller you have to remove it from the board. The ATTiny20 requires +5V to program, and the digital control lines for the TPA can't handle that voltage.
I could do another group buy, but honestly I don't have the time and I really don't want to disappoint people with long lead times like the several months it took to get the last group buy out. I could get a local electronics shop to do the build instead of doing it myself, but there'd be a minimum order quantity of 50 or more required to hit a reasonable price point, and I'd have to settle on one type of board (stereo or Pro) versus 3 different types. Given enough interest I'll do it.
Attachments
Hey, sorry for falling off the face of the earth
I'll put together the Pro schematic/firmware/etc tonight and release it.
Welcome back.
And thank you for the Pro schematic.
If your next amp uses the tpa3255 or tpa3245, I will be interested in one. I think I can gather a few more interested people. I have read somewhere the tpa3245 sound better tpa325x, I am not sure why as the spec looks similar.
Since GMarsh may not be doing a GB anytime soon, I wholeheartedly recommend the TPA3251 amp from 3eaudio. There's a thread in Vendor Bazaar. You can order from ebay as well. It is an outstanding amp. No customization like the Wieners though.
Didn't want to say anything before, but since things here are on hold, thought I'd mention it.
Didn't want to say anything before, but since things here are on hold, thought I'd mention it.
Only catch with the 3245 is top mounted heatsinks are hard. There isn't really any off the shelf heatsink from Mouser/Digikey/wherever or even the R-Theta catalog that suits the board, and getting something custom made would cost a lot. I also like the pad-down parts as it allows components to be placed closer to the IC. The thermal performance isn't as good, but unless you're driving a huge amount of power out of one of these amps, it's not really an issue. The Wiener amp is intended for home audio listening anyway, at reasonable indoor volume levels, not as an outdoor PA amplifier or something.
The 3244 looks to be identical to the 3245, other than power ratings and being pad-down versus pad-up. Comparing the TPA3244 and the 3250 specs, the 3244 looks a bit more efficient, has a slightly lower output noise (55uV vs 60uV, 0.76dB, it ain't much), and a lower power supply range.
And the pinout is almost identical - only difference I can spot on the datasheet is the INPUT_A/INPUT_B pins being swapped, which for all I know could be a typo. And even if they are swapped, it's just a matter of flipping the input/output polarity for the channel. So in theory, you could drop the 3244 directly into the Pro design with zero changes.
Me hand-assembling dozens of amplifiers is on hold
Given enough interest I'll get them professionally made at a PCB house, but yeah, I'll need a MOQ to make that worthwhile.
Hi Gary,
I missed out on the last Pro build cycle, I was busy last summer building a garage. Is it possible for me to buy a few blank pcb's? and any parts that you have left over. I can solder them up myself. I would need a BOM and the hex file would also help, so that I do not have to compile the source code. I can program, if you do not have any already done, the mcu since I have a atmel programmer.
If you have no pcb's on hand to sell, would you provide me with the pcb fab data? I promise that I would keep it confidential and only use the information for myself.
Thanks
Rick
I missed out on the last Pro build cycle, I was busy last summer building a garage. Is it possible for me to buy a few blank pcb's? and any parts that you have left over. I can solder them up myself. I would need a BOM and the hex file would also help, so that I do not have to compile the source code. I can program, if you do not have any already done, the mcu since I have a atmel programmer.
If you have no pcb's on hand to sell, would you provide me with the pcb fab data? I promise that I would keep it confidential and only use the information for myself.
Thanks
Rick
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