Does Q3 have to be pre-biased or can I just use a MMBT3904?
Some LME49600 implementations - Page 11
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I'm hoping someone who has had a prototype board will get back to me regarding any problems getting any of the fit-critical components such as jack sockets, switch or pot, before I do a respin. I have a limited number of these parts on hand, I don't want anybody left hung out to dry if they're having trouble getting them, and I want to keep my options open with regard to using different parts before I order the new boards.
I have another board I'm working on, I get a discount if I order both together, the turnaround is about 2 weeks, so it will be 3 weeks at least before I have respun boards. I'm sorry, I hope you'll be able to hang on 'till I get it done.
I wrote the above before I saw your last post.
R20 is 47k. I had 1M in the original schematic, it didn't work out.
R17, R23, R25, R27 are 150R
R18, R24, R26, R28 are 1k5 These values give 13.75V rails. See the last paragraph of #147 for some comments on this.
That's the correct relay.
Yes, you can use MMBT3904, pre-biassed is not required. I tried to eliminate the anomalies in the BOM which arose as the result of drawing in haste due to my mind running ahead of my fingers, but evidently not with complete success.
Edited by wakibaki - 6/18/12 at 5:42pm
this is the audio jack I usually use, I'm pretty sure it will fit.
I have the BOM about 95% complete.
Digi-key does not have the alps pot...you will have to Mouser that.
L3 and L4 were a little tougher, not much information to x-reference from.
How about this?
Changed my mind...this one:
Edited by Avro_Arrow - 6/18/12 at 6:36pm
The dimensions are good, but the one I have is 78 ohms @ 1-25MHz, which was the lossiest at the lowest frequency I could find. They're there to assist in preventing spikes from the rectifier getting back onto the wire from the wallwart.
They could be superfluous, and they could be doing very little good. I just noticed that the O2 had some hum problems which were cured by a grounding wire. I suggested to the designer that this might indicate that there was some radiation from these wires, especially since he commented that the amp was audibly interfering with some other equipment when brought near, but he dismissed the suggestion, and anyway he had his fix as far as the amp itself was concerned. I haven't noticed any problems, so maybe they're working.
I'll see if I can find some lower frequency ones on Digikey.
I think the power and 3.5 jacks are OK.
Edited by wakibaki - 6/18/12 at 7:12pm
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|
Case and Knob are builders discretion.
Volume pot on Mouser:
Q3 is any general purpose SOT23 NPN transistor
L3/4 can be shorted, put a ferrite on the wire from the wallwart, close to the amp.
J1/2 are 2-pin headers (for jumpers), or run wires to a DPST switch.
Volume pot looks good with 15mm shaft, I had to take a diamond cutting disk to mine.
Edited by wakibaki - 6/19/12 at 2:55pm
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It's the same box as the O2 used.