my simple rustic pine Wiener build
Hi,
I finally got around to completing assembling my Wiener "Mk-I"? into a stained pine box with better quality binding posts and RCAs.
A 50K ebay stepped attenuator completes the mix.
Using a 50W 19V laptop style SMPS. This is currently driving some "Econowave" type Waveguide speakers direct from a Raspberry Pi with hifiberry DAC.
I was a bit overenthusiatisic with the stain/varnish, but other than that it has come out quite well:
I've mounted a strip of aluminium under the PCB with the heat pad to provide additional heatsinking for the IC.
Hi,
I finally got around to completing assembling my Wiener "Mk-I"? into a stained pine box with better quality binding posts and RCAs.
A 50K ebay stepped attenuator completes the mix.
Using a 50W 19V laptop style SMPS. This is currently driving some "Econowave" type Waveguide speakers direct from a Raspberry Pi with hifiberry DAC.
I was a bit overenthusiatisic with the stain/varnish, but other than that it has come out quite well:
I've mounted a strip of aluminium under the PCB with the heat pad to provide additional heatsinking for the IC.
Making progress on the "big wiener" PBTL card now.
Yeah, left/right inputs/outputs are mixed up
Trying to come up with a good way to configure the attenuation settings, as I don't really want to do a 6 position DIP switch for each TPA. Considering putting both parts in slave mode and making the AVR generate a 100KHz sync clock, and using a single 2 or 3 position DIP switch to set the gain for both channels, if GVDD tolerances allow.
Yeah, left/right inputs/outputs are mixed up
Trying to come up with a good way to configure the attenuation settings, as I don't really want to do a 6 position DIP switch for each TPA. Considering putting both parts in slave mode and making the AVR generate a 100KHz sync clock, and using a single 2 or 3 position DIP switch to set the gain for both channels, if GVDD tolerances allow.
Still pondering some design things on the "big wiener" stereo card, so I had a go at the monoblock PBTL wiener tonight. Made a good bit of progress!
Card's still 50x100mm, even managed to keep all my bed of nails fixture contacts in the same places. Inductors are Coilcraft VER2923's. Output film caps are doubled up for a little less ESL (eg, 4 ohm card will use two 0.68uF caps versus a single 1.5uF cap).
Still have to do some tweaking (I'm looking at the pic and noticing things I want to change), get the DIP switch configuration to fit on the back of the card again, throw a BOM together, etc.
Card's still 50x100mm, even managed to keep all my bed of nails fixture contacts in the same places. Inductors are Coilcraft VER2923's. Output film caps are doubled up for a little less ESL (eg, 4 ohm card will use two 0.68uF caps versus a single 1.5uF cap).
Still have to do some tweaking (I'm looking at the pic and noticing things I want to change), get the DIP switch configuration to fit on the back of the card again, throw a BOM together, etc.
Gonna call the PBTL monoblock design done!
Schematic:
Front:
Back:
Assuming I sell minimum 25 of these things, cost is gonna be approx $100 CAD/pop. There's half as many inductors but they cost 4x as much - there's no quantity price breaks until 250 from Coilcraft, and they have to be bought and shipped separately from Coilcraft themselves. Filter kits (for 4/6/8 ohm configurations) will be approx $20 CAD. Chassis mounting kits (standoffs/screws) probably $12 this time.
I'm probably going to give up on the "big wiener" stereo card idea. There's not a huge cost savings combining two channels onto one PCB, the main spendy things (film caps, power supply caps, inductors, TPA chip, etc) are doubled on the stereo card anyway, and the small handful of things that would be shared on a stereo card (microcontroller, 4 position DIP switch, 5V regulator, etc) are pretty cheap. PCB area is pretty much double on the stereo card so there's no major savings having it on a single PCB versus two.
Sales of the existing stereo Wiener card will still go ahead. Only catch is only 8 ohm and 16 ohm cards will be available, as the ICE 1D14A-100M inductors are still unobtanium (Sept 1st is the current Mouser ship date...), and I'd rather not get Sagami inductors again - getting the Jotrin order here for them cost me $75 CAD in customs duties/shipping/etc and I'd rather not deal with that again.
Gonna give this design a proper review now, and make a fresh mouser BOM so I've got current prices on all the parts, and I'll have group buy #2 up in a few days.
Schematic:
Front:
Back:
Assuming I sell minimum 25 of these things, cost is gonna be approx $100 CAD/pop. There's half as many inductors but they cost 4x as much - there's no quantity price breaks until 250 from Coilcraft, and they have to be bought and shipped separately from Coilcraft themselves. Filter kits (for 4/6/8 ohm configurations) will be approx $20 CAD. Chassis mounting kits (standoffs/screws) probably $12 this time.
I'm probably going to give up on the "big wiener" stereo card idea. There's not a huge cost savings combining two channels onto one PCB, the main spendy things (film caps, power supply caps, inductors, TPA chip, etc) are doubled on the stereo card anyway, and the small handful of things that would be shared on a stereo card (microcontroller, 4 position DIP switch, 5V regulator, etc) are pretty cheap. PCB area is pretty much double on the stereo card so there's no major savings having it on a single PCB versus two.
Sales of the existing stereo Wiener card will still go ahead. Only catch is only 8 ohm and 16 ohm cards will be available, as the ICE 1D14A-100M inductors are still unobtanium (Sept 1st is the current Mouser ship date...), and I'd rather not get Sagami inductors again - getting the Jotrin order here for them cost me $75 CAD in customs duties/shipping/etc and I'd rather not deal with that again.
Gonna give this design a proper review now, and make a fresh mouser BOM so I've got current prices on all the parts, and I'll have group buy #2 up in a few days.
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Well, I've got the schematic posted. Feel free to add up the prices of everything, convert to $CAD, add 15% HST, add $60 or more of shipping/brokerage to bring parts here, I'd be surprised if I'm making minimum wage building these things. I made about $12/card on the last build after all was said and done, paid off half a vet bill and that was it.
Original plan was to make $20ish but the inductor crisis screwed things up, then I lost $90ish mailing out a 2nd card after the first got lost in the mail.
I can't compete with chinese cards on price obviously. Don't plan to.
Original plan was to make $20ish but the inductor crisis screwed things up, then I lost $90ish mailing out a 2nd card after the first got lost in the mail.
I can't compete with chinese cards on price obviously. Don't plan to.