Got your payment - didn't make it onto my order spreadsheet somehow, I ordered several extra TPAs so you're safe. Just went through my interac/paypal history again and double checked, every single payment I've received is accounted for on the order spreadsheet, so this won't be happening to anyone else.
Anyway, I'm behind on this, it's a spare time project and sadly I've had very little of it. PCBs and inductors are here, Mouser order is on the way.
Mouser order is stuck in customs. Yay!
And my solder paste arrived yesterday. Gonna try building a stereo cards using the toaster oven reflow method.
I've got a little Omega CN7500 temperature controller that can be programmed with a temperature profile. Right now it runs my "sans francs sous vide" cooking setup, I'll see how well it works on the toaster oven.
And my solder paste arrived yesterday. Gonna try building a stereo cards using the toaster oven reflow method.
I've got a little Omega CN7500 temperature controller that can be programmed with a temperature profile. Right now it runs my "sans francs sous vide" cooking setup, I'll see how well it works on the toaster oven.
Update: first PBTL card built!
Plus 5 more PBTL cards without through-hole parts, and six cards with TPA's installed/tested.
Found a BOM error in the Mouser PBTL BOM, there's a 0.22uF cap called out as C28, this should be C29.
Tearing apart the house right now trying to find my AVR programmer.
Plus 5 more PBTL cards without through-hole parts, and six cards with TPA's installed/tested.
Found a BOM error in the Mouser PBTL BOM, there's a 0.22uF cap called out as C28, this should be C29.
Tearing apart the house right now trying to find my AVR programmer.
Stencil and parts arrived yesterday. Casework/PS is pre-drilled for dual PBTL boards, so should come together quickly. Will be swapping out my (excellent) Wiener stereo card.
Is a 6ohm build the best choice for my drivers? Impedance curve below.
BK
Is a 6ohm build the best choice for my drivers? Impedance curve below.
BK
An externally hosted image should be here but it was not working when we last tested it.
Apologies for the slow response... that impedance curve is well past 10 ohms in the 10-20KHz band, which is where you'll get peaking happening due to mismatch. I'd go 6 or 8 ohms, and put a RC snubber in series with the speaker to push that impedance down flat to 6 or 8 over that range. By chance do you have a data table corresponding to that plot?
Also, BK, can you PM me your address? Can't find it anywhere in my paypal, PMs or email.
And update for everyone - so far only rhing's order is sent. Had no car last week, had to repair a bunch of stuff to pass MVI and inconvenience a co-worker to get a ride into work - didn't want to overstep a favor by asking to hit up the post office. Sticker's on the car now, need to pick up some envelopes/boxes for the full builds tomorrow, finish/pack things over the weekend and get things mailed out next week.
All PBTL orders are built, and 3 out of 10 stereo cards are built/tested/working. Still working on getting my toaster oven setup going for the rest.
Also, BK, can you PM me your address? Can't find it anywhere in my paypal, PMs or email.
And update for everyone - so far only rhing's order is sent. Had no car last week, had to repair a bunch of stuff to pass MVI and inconvenience a co-worker to get a ride into work - didn't want to overstep a favor by asking to hit up the post office. Sticker's on the car now, need to pick up some envelopes/boxes for the full builds tomorrow, finish/pack things over the weekend and get things mailed out next week.
All PBTL orders are built, and 3 out of 10 stereo cards are built/tested/working. Still working on getting my toaster oven setup going for the rest.
Time to broil some wieners!
I'm using an Omega CN7500 ramp/soak temperature controller programmed with a suitable reflow curve. Dry-running the toaster oven, everything runs great except the oven doesn't cool down quick enough when the cycle is done, simple solution is to open the door manually.
My ghetto stenciling jig made with electrical tape and spare PCBs:
For this job I'm using "Mechanic" brand, SnPb solder paste bought off eBay. It's a fraction of the cost of proper Kester paste, but seems to be well reviewed on hobby sites.
I went with SnPb because I'd have to buy new lead free solder/tips/flux/etc to do rework if I did lead free reflow. Anyway, on goes the paste...
... and we've got a pasted board. This one came on kind of heavy, guess we'll see how it turns out:
SMT parts placed. Everything self-centers due to surface tension so you can be a little off placing everything and it's OK.
And through the oven it goes... voila, SMT is soldered:
Through-hole parts are installed next, and we've got a completed Wiener.
Needs a bit of cleaning first (there still is a small bit of flux residue left, plus cleanup from the TH parts), then I'll pull the kapton off the DIP switches and program the card.
Overall, gotta say toaster oven reflow works pretty good. I banged out 6 stereo cards last night, I can place parts about twice as fast compared to hand soldering SMT. Had some bridging between pins on the TPA that I had to fix with a bit of solder wick and fresh solder, and one tombstoned 220nF bootstrap cap on one board, but other than that everything worked out great.
I'm using an Omega CN7500 ramp/soak temperature controller programmed with a suitable reflow curve. Dry-running the toaster oven, everything runs great except the oven doesn't cool down quick enough when the cycle is done, simple solution is to open the door manually.
My ghetto stenciling jig made with electrical tape and spare PCBs:
For this job I'm using "Mechanic" brand, SnPb solder paste bought off eBay. It's a fraction of the cost of proper Kester paste, but seems to be well reviewed on hobby sites.
I went with SnPb because I'd have to buy new lead free solder/tips/flux/etc to do rework if I did lead free reflow. Anyway, on goes the paste...
... and we've got a pasted board. This one came on kind of heavy, guess we'll see how it turns out:
SMT parts placed. Everything self-centers due to surface tension so you can be a little off placing everything and it's OK.
And through the oven it goes... voila, SMT is soldered:
Through-hole parts are installed next, and we've got a completed Wiener.
Needs a bit of cleaning first (there still is a small bit of flux residue left, plus cleanup from the TH parts), then I'll pull the kapton off the DIP switches and program the card.
Overall, gotta say toaster oven reflow works pretty good. I banged out 6 stereo cards last night, I can place parts about twice as fast compared to hand soldering SMT. Had some bridging between pins on the TPA that I had to fix with a bit of solder wick and fresh solder, and one tombstoned 220nF bootstrap cap on one board, but other than that everything worked out great.
Thanks for suggesting toaster oven reflow BK, it's worked extremely well. I'm up to 10 stereo cards toasted now, I'm getting a lot quicker at placing parts.
Unfortunately I hit a snag... due to a math mistake on a spreadsheet, I'm out of the 0.47uF film capacitors required for the 8 ohm stereo amps. I'm going to order more through work tomorrow but as an additional snag, I'm travelling next week and back in NS on Nov 2. So five orders (below) will have to ship around Nov 3 or 4 ish.
Shipped so far:
bk856er, rhing
Ready to ship (orders are put together - picking up shipping supplies tomorrow, packaging up tomorrow night, mailing out Friday):
snake69fast, nwplace, lostthumb, dizrotus, Richard K, afoor, aterren, Joel W, taisho_daniel, ginum, bruce potter, bchristmas
Held up by cap shortage. Boards are fully constructed other than missing caps:
eplates, gorovik, nwboater, awajoy, alfi
Thanks everyone for your patience, apologies this has taken so long.
Unfortunately I hit a snag... due to a math mistake on a spreadsheet, I'm out of the 0.47uF film capacitors required for the 8 ohm stereo amps. I'm going to order more through work tomorrow but as an additional snag, I'm travelling next week and back in NS on Nov 2. So five orders (below) will have to ship around Nov 3 or 4 ish.
Shipped so far:
bk856er, rhing
Ready to ship (orders are put together - picking up shipping supplies tomorrow, packaging up tomorrow night, mailing out Friday):
snake69fast, nwplace, lostthumb, dizrotus, Richard K, afoor, aterren, Joel W, taisho_daniel, ginum, bruce potter, bchristmas
Held up by cap shortage. Boards are fully constructed other than missing caps:
eplates, gorovik, nwboater, awajoy, alfi
Thanks everyone for your patience, apologies this has taken so long.
Gonna be that guy holding up the line at the post office tomorrow 
Came across some Mostek 470nF film caps in a box at work, so I've got two more 8 ohm amps built up - gorovik/eplates are mailing out tomorrow also. eplates, I need your mailing address, I'll PM you in a sec.
Also, correction: taisho_daniel and bruce potter will not be mailing out tomorrow, turns out I'm short on 1.0uF capacitors too
Came across some Mostek 470nF film caps in a box at work, so I've got two more 8 ohm amps built up - gorovik/eplates are mailing out tomorrow also. eplates, I need your mailing address, I'll PM you in a sec.
Also, correction: taisho_daniel and bruce potter will not be mailing out tomorrow, turns out I'm short on 1.0uF capacitors too
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