Won't be for less than 3 weeks. I'll PM you when they're available.
I prefer to use the toaster oven, but I had the advantage of being able to make a solder stencil. Solder paste and reflowing is still possible if you place the solder paste by hand, you can run a bead down all the pads of a chip, but it's more prone to problems, sometimes the surface tension skews the chip instead of squaring it up on the pads. I usually watch through the door and get in there and straighten it up before the solder has a chance to set on the odd occasion that it happens. Doing all the solder by hand with a syringe and needle takes some of the advantage out of doing it by reflow, it adds to the overall work and stress.
I kept the res and caps fairly well spaced because the webs between the pads on the stencil get etched away if they're too thin. 'Fairly well spaced' is only in a manner of speaking, but they are hand-solderable in my experience.
Perhaps a compromise might be a good introduction to reflowing. Some of the parts are thru-hole and require hand-soldering anyway. You could do the res and caps by reflow and place the chips by hand.
It's great when reflow works out, all the components settle down and pull themselves into alignment on the pads because of surface tension. There's very little flux residue and the whole thing looks nice and professional.
Whatever route you choose, good luck!
I found a mistake in the BOM.
In the third line it says you need thirteen 1k resistors...you only need four.
Preliminary Digi-Key BOM
There could be errors or omissions.
|Digi-Key Part Number||Manufacturer||Manufacturer Part Number||Customer Reference||Quantity 1||Description|
|P10.0AACT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-14NF10R0U||8||RES 10.0 OHM 1/2W 1% 1210 SMD|
|P150FCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF1500V||4||RES 150 OHM 1/4W 1% 1206 SMD|
|P1.00KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF1001V||13||RES 1.00K OHM 1/4W 1% 1206 SMD|
|P1.50KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF1501V||4||RES 1.50K OHM 1/4W 1% 1206 SMD|
|P4.70KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF4701V||4||RES 4.70K OHM 1/4W 1% 1206 SMD|
|P47.0KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF4702V||1||RES 47.0K OHM 1/4W 1% 1206 SMD|
|P100KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF1003V||4||RES 100K OHM 1/4W 1% 1206 SMD|
|P120KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF1203V||2||RES 120K OHM 1/4W 1% 1206 SMD|
|P390KFCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF3903V||3||RES 390K OHM 1/4W 1% 1206 SMD|
|P470FCT-ND||PANASONIC ELECTRONIC COMPONENTS (VA)||ERJ-8ENF4700V||OPT.||2||RES 470 OHM 1/4W 1% 1206 SMD|
|399-1167-1-ND||KEMET (VA)||C0805C104K4RACTU||14||CAP CER 0.1UF 16V 10% X7R 0805|
|399-3525-1-ND||KEMET (VA)||C1206C106K4RACTU||8||CAP CER 10UF 16V 10% X7R 1206|
|399-1140-1-ND||KEMET (VA)||C0805C331K5RACTU||2||CAP CER 330PF 50V 10% X7R 0805|
|718-1525-1-ND||VISHAY SPRAGUE (VA)||TR3D476K025C0150||4||CAP TANT 47UF 25V 10% 2917|
|P12388-ND||PANASONIC ELECTRONIC COMPONENTS||EEU-FM1E471||7||CAP ALUM 470UF 25V 20% RADIAL|
|LM7805CT-ND||FAIRCHILD SEMICONDUCTOR||LM7805CT||1||IC REG 1A POS 5V TO-220|
|296-13869-5-ND||TEXAS INSTRUMENTS||LM317KCS||2||IC VOLT REG POS ADJ 3TERM TO-220|
|296-21577-5-ND||TEXAS INSTRUMENTS||LM337KCSE3||2||IC VOLT REG NEG 1.5A ADJ TO-220|
|LME49600TS-ND||NATIONAL SEMICONDUCTOR||LME49600TS/NOPB||2||IC AMP BUFFER AUD HI FI TO-263-5|
|296-17157-1-ND||TEXAS INSTRUMENTS (VA)||LM2901QDRQ1||1||IC QUAD DIFF COMPARATOR 14-SOIC|
|LME49990MA-5-ND||NATIONAL SEMICONDUCTOR||LME49990MA/NOPB||2||IC OP AUDIO LOW NOISE 8SOIC|
|LTC1150CS8#PBF-ND||LINEAR TECHNOLOGY||LTC1150CS8#PBF||2||IC OPAMP CHOP-STBL W/CAPS 8SOIC|
|ES1A-TPCT-ND||MICRO COMMERCIAL CO (VA)||ES1A-TP||3||DIODE FAST REC 1A 50V DO214AC|
|CP-058BH-ND||CUI INC||PJ-058BH||1||CON PWR JCK 2.5 X 5.7MM HIGH CUR|
|CP1-3543-ND||CUI INC||SJ1-3543||2||CONN JACK STEREO R/A 3PIN 3.5MM|
|CP1-3543N-ND||CUI INC||SJ1-3543N||ALTERNATE||2||CONN JACK STEREO R/A 3PIN 3.5MM|
|CP3-1001-ND||CUI INC||PP3-002B||MATE FOR POWER JACK||1||CONN 2.5MM FEMALE PLUG 5.5MM OUT|
|PB1061CT-ND||TE CONNECTIVITY POTTER & BRUMFIELD (VA)||IM03GR||1||RELAY TELECOM DPDT 2A 5V|
|450-1594-ND||TE CONNECTIVITY ALCOSWITCH||MSS4200R04||1||SWITCH SLIDE 2POS 0.276"BLCK T/H|
I ended up hand soldering everything. I did use solder paste though...
I put just a little dab of paste on the pads, used the tweezers to hold
the component and just touched the iron to it. It seemed to be easier
to control the amount of solder applied that way.
Here is the fully populated board:
I had a pot with a switch laying around that needed a new home.
I just cut off the switch pins and it actually fit!
I used OPA211 for the servo amp. I have not cut the board yet...I want to
see if mine buzzes too.
R46. The value is not critical, it should be equal to the DCR of the coil to get the fastest drop-out on power off. Coil power is 50mW, supply is 5V so current is 10mA and best value is 500R. You could parallel 2 * 1k on the same pads. Sorry about the inaccuracy, I had it somewhere in my head that the current was 5mA.
Looking good there A_A!
Well, it works...sort of.
1. The first problem is the voltage from the 337 regulators.
The 317s come out pretty close to the 13.75 volts.
One of the 337s comes out at 14 volts and the other at 13.8 volts.
2. Next (and maybe related to the first) is it won't come out of protection (I just defeated it for the time being).
3. The servo takes a long time to settle, maybe 15 to 20 seconds for a sudden shift in input offset.
One channel seems to settle around -0.5 mV and the other around 2 mV (I used OPA211 for the servo).
All that being said, it sounds fine (other than the buzz, but that was expected).
I will be interested to see other peoples results.
It also gets pretty hot...uncomfortable to touch.
I'm using a 16 VAC @ 2.5 A transformer which gets me +- 20 volts at the input to regulators.
The regulators, LME49990, OPA211 and LME49600 all get hot.
The LME49990 in my DAC gets only slightly warm (it only has +- 6 volts rails though).
After about half an hour, offset sits at -0.4 mV in one channel and 0.4 mV in the other.