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Some LME49600 implementations - Page 12

post #166 of 288
Thread Starter 
Quote:
Originally Posted by Misterrogers View Post

wakibaki - I'd love a couple of boards if/when there are any available. Cheers!

 

Won't be for less than 3 weeks. I'll PM you when they're available.

 

w

post #167 of 288

I have my parts from Digikey on the way. I was thinking about just soldering with an iron, but given the proximity of the pads would it be easier to just use a toaster oven? I have one I haven't used in years.

post #168 of 288
Thread Starter 

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!

 

w

post #169 of 288
Thread Starter 

It occurred to me to mention that you need to dog-leg the pins on the regulators to make them sit down so that everything fits in the case. Be careful not to make them short on the gain setting resistors.

 

w

post #170 of 288

I found a mistake in the BOM.

In the third line it says you need thirteen 1k resistors...you only need four.

Quote:
Originally Posted by Avro_Arrow View Post

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
post #171 of 288

Opps...just found another one.

 

R46 is listed as 1k in the BOM and 100R on the schematic...

post #172 of 288

SMD all soldered up except fpr R46...I'll have to scrounge one up for there.

 

Waki01.jpg

 

Now on to the through holes!

post #173 of 288

Looking very good. :)

 

Did you end up using a stencil and an oven?

post #174 of 288

Thanks!

 

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:

 

Waki02.jpg

 

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.

post #175 of 288

Nice work A_A!

post #176 of 288
Thread Starter 

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.

 

w

 

Looking good there A_A!


Edited by wakibaki - 7/1/12 at 4:48pm
post #177 of 288

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.

post #178 of 288

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.

post #179 of 288

I got the buzz to go away...just cut the board like Wakibaki did.

I didn't cut mine as much as Wakibaki.

post #180 of 288
Subjectively - how does it sound?
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