The warning was because of a couple of posted links, and although they have been deleted, it will take some time for the warnings to quit.
How goes it with the Class AB minty amp? I think the Class AaG guys are either talking or hibernating rather than doing, so your competition is a couple of chip amplifiers. I've had a redo on mine because I'd like to explore the "compact amplifier" category which has more options than my car chip.
Can I use a screw terminal strip for in/out/pwr connections?
"Electronics" part is a piece of cake, but standard size jacks and plugs take way too much space or directly don't fit in.
Or at least a row of, say, .1" or .156" pitch plug in connectors on some edge?
Really don't know how to fit 2 in jacks, 2 out ones plus a Pwr connector in an Altoids or similar tin can.
Please consider that nobody has posted a finished example yet, I bet space and layout have a big influence on it.
Thanks.
"Electronics" part is a piece of cake, but standard size jacks and plugs take way too much space or directly don't fit in.
Or at least a row of, say, .1" or .156" pitch plug in connectors on some edge?
Really don't know how to fit 2 in jacks, 2 out ones plus a Pwr connector in an Altoids or similar tin can.
Please consider that nobody has posted a finished example yet, I bet space and layout have a big influence on it.
Thanks.
Power connection:Can I use a screw terminal strip for in/out/pwr connections? "Electronics" part is a piece of cake, but standard size jacks and plugs take way too much space or directly don't fit in. Or at least a row of, say, .1" or .156" pitch plug in connectors on some edge? Really don't know how to fit 2 in jacks, 2 out ones plus a Pwr connector in an Altoids or similar tin can.
You can hardwire power and so a little rubber grommet can protect the cord.
Or power can use a non-shorting jack, such as a barrel jack--power jack is an option but not a requirement.
Input jack:
An 1/8" stereo jack works for input in little space. Typical uses with television, computer or mp3 player all use 1/8" anyway.
It is also possible to use RCA jacks, but those are slightly more difficult to fit.
Speaker connectors:
These can be a mini 4 terminal spring clip or screw terminals or binding posts or RCA's, which are all non-shorting and available in a wide variety of sizes.
I hope these ideas were helpful.
Very off the original contest here I have a question. Could someone take this same original premise and design one of these Altoids amplifiers to drive a set of headphones? I would want to use the output from say an Ipod and amplify it with a better amplifier. Could the power supply then be a second tin with rechargeable lithium or NiMh other battery and drive the circuit instead of an AC power supply?
bobodioulasso,
Thanks for the link. Now I just have to figure out why my PDF viewer keeps crashing! But I did see the parts list on another site and just can't see the schematic yet. It looks like it would be a nice project. Thanks a lot. Anyone build one of these, and what other changes has anyone made to the circuit. I see they talk about oscillation problems with one of the opamps.
Thanks for the link. Now I just have to figure out why my PDF viewer keeps crashing! But I did see the parts list on another site and just can't see the schematic yet. It looks like it would be a nice project. Thanks a lot. Anyone build one of these, and what other changes has anyone made to the circuit. I see they talk about oscillation problems with one of the opamps.
Dear danielwritesbac, thanks, now I'll have to buy some canned mints
or visit my neighbourhood Chinese dollar store. Stay tuned.Dear Kindhornman: why carry 2 tins (plus the IPod)?
I'll build something like you are asking for, but all in one, as a 1>4 headphone extender/booster.
I hate it when somebody sees me enjoying something and can't share it.
I guess up to 4 headphones will solve that
.I'll post it here.
A couple 3.6V Lithium batteries will be best, but I have some unused 3.6V mini wireless phone battery packs, now they have a new task on Earth
The whole shebang fits into a single mint Tin.
jmFahey,
I'll look forward to see what you propose. I told my daughter about the little tin amplifier and she jumped at the chance to build something like that. She wants to become an engineer so perhaps this will help her decide what type she may want to be. The one that bobodioulasso posted was running on a 9v battery.
I'll look forward to see what you propose. I told my daughter about the little tin amplifier and she jumped at the chance to build something like that. She wants to become an engineer so perhaps this will help her decide what type she may want to be. The one that bobodioulasso posted was running on a 9v battery.
JMFahey,
That sounds great. I bet your daughter will soon tire of working at MickeyD's and come to her senses. These days you better get to college, not many ways around it if you want to survive. I'll have to look at the LM386. I am familiar with the 3886 but not going to happen in one of these cans!.
That sounds great. I bet your daughter will soon tire of working at MickeyD's and come to her senses. These days you better get to college, not many ways around it if you want to survive. I'll have to look at the LM386. I am familiar with the 3886 but not going to happen in one of these cans!.
I have some questions about if my amp can be in your contest........
I'm building it in a very small project box with its OWN BATTERIES, so the power input requirement can be much less because it's just charging batteries (plan using 12V, 300mA adaptor) so most power comes from the internal batteries, and so it does not need to always be connected to external power to operate.
I am using BTL output AN7522N because it's very loud using only 9-12VDC, and makes very little heat. I have plenty of these salvaged from dead stereo TV's. http://www.lemona.lt/LIUSE/Pdf/AN7522N.pdf
It's rated 5W/ch @ 8R but with over-heatsinking it, I have NO issues at all with 4R loads despite the datasheet ratings, and it's VERY loud. (I'm guessing 8-10WRMS @ 4R) WILL me running 10W/ch @ 4R be OK???
I don't want to install a whole bunch of jacks, can I just solder a 1/8" headphone cord to my PCB and run it outside the case with the plug on the end? It would simplify things some.
I may use the spring loaded speaker terminals like you mention, but banana jacks would be easier (and cleaner looking IMO)
I would also like to have a + and - pair of banana jacks for my ~12V power input, so I have either the option of wiring it to a 12V AC adaptor OR 12V cigarette lighter cord, or even straight to a car battery, so I have any option for power. Would that be OK?
Every bit as suitable as a Prius towing an Airstream.
Safe operating area - Wikipedia, the free encyclopedia
Faults in Transistors
Problem: Over-current. Hazardous design is unlikely to win. Failure mode: BJT's such as the miniature output devices inside of those chips do contain insulating layer that gets hammered while running and over-spec use causes seriously decreased longevity. Have you considered running parallel mode to get a safety margin?
Yet more hazard: Over-voltage. The chip when running maxes out at 13.5v, but car alternator when running outputs 14.4v to 14.8v when the engine is on.
Panasonic AN7522N I wouldn't want to be impolite; however over-current combined with over-voltage is a recipe for disaster that, probably won't win.
Perhaps you would like to explore TDA8561Q, TDA1554Q and similar automotive chips rated to withstand your application and provide decent longevity? Here is a thread on that sort: http://www.diyaudio.com/forums/chip-amps/158644-12v-dc-gainclone-3.html#post3260469 It is also possible to use little discrete amplifiers.
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Understand. I was thinking about the chip and I forgot to mention I would put a custom regulated charger circuit (my own design) in the case, the internal 9-cell, 10.8V (~12V peak full charge) NiCd battery and amp will always see less than 14V, even if fed as high as 18V (unregulated wall-wart). The charge voltage & current would be limited.
I don't have anymore 12V automotive chips, lost ALL of them (and all my equipment, tools, amps, etc) in a (possibly arson) house fire.
I'm not really worried about SOA on the cheap TV chip if it's kept cooler than stock, as I have driven these chips HARD into clipping & 4 ohms intentionally for long periods of time trying to kill one, and have yet to see one die, and also I have plenty of AN7522 spares, but I will still keep looking for better chips. After losing near everything, I'm just glad to even be doing electronics at this moment. I miss my old bag of Phillips TDA1558Q chips!!! They would be perfect right now!
Thanks for your swift reply Daniel, and good luck too all doing this project. Gotta keep the ideas flowing. This has been an interesting thread.
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Those are fun. I like to miswire the + amplifiers into reverb amplifiers for rear channel speakers. But, if it is used BTL, the gain is extremely high and can be slightly noisy. TDA1558Q Manu Philips Encapsulation Zip 17 2 x 22 w or 4 x 11 w Single Ended | eBay Not much demand for it because of that huge gain; however, they're just $6. I suppose that the gain indicates it was made for economical build for car tape-radio players. It could be used to amplify a really weak MP3 player quite aggressively.
However, the more normal gain of the 1554Q is easier to use and just $7. TDA1554Q Manu Philips Encapsulation Zip 4 x 11 w Single Ended or 2 x 22 W | eBay
There's few datasheet errors--actually it needs a 10K resistor to run the mute (that circuit doesn't require high amperage). The actual operating range is 6v to 16.3v. It is capable of 22W to 4R@10%THD or 11W to 8R@10%THD. The efficiency at about 12v is somewhat higher than the datasheet indicates. This one should be quite easy for a mint tin amp for driving 8 ohm speakers.
Or you could try the 1560Q if you like push for power applications that work safely. That one does about 9 or 10 watts to 8 ohms in Class AB and then about 22 watts more of poor quality class H that does sound a lot better than clipping. Basically, the H mode thumps and bangs the bass beat of popular music without clipping. In that chip, the class H mode is a sort of headroom management utility and it is made to play mainly in class AB. TDA1560Q Manu Philips Encapsulation Zip 17 40 w Car Radio High Power Amplifier | eBay These are a little higher at $8 plus a bit more in parts. Those are less efficient (higher heat) and their voltage range might be unhandy if battery powered.
P.S.
For a step up in audio quality, look up the "compact stereo" class of chip amplifiers. Like the car chip, they're made to run in small metal enclosures; however, unlike the car chip, the "compact stereo" chip has full access to the feedback loop so that you can adjust it to fit your preferences. And, some of the "compact stereo" chips can do high resolution audio.
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Originally Posted by Kindhornman
JM,
I told my daughter about the amp and that you thought that you could do better, she was very excited. Next thing you know now my nephew who I am also raising said he wants to build one also. I look forward to whatever you come up with. I looked at the LM386 chip and seems plausible. Are there any impedance limits, do I have to make sure they have a certain type of headphones. Both have some over ear Sony headphones, not sure what the impedance rating is but they do work on there Ipods and Blackberry phones.
JM,
I told my daughter about the amp and that you thought that you could do better, she was very excited. Next thing you know now my nephew who I am also raising said he wants to build one also. I look forward to whatever you come up with. I looked at the LM386 chip and seems plausible. Are there any impedance limits, do I have to make sure they have a certain type of headphones. Both have some over ear Sony headphones, not sure what the impedance rating is but they do work on there Ipods and Blackberry phones.
Fine.
No impedance problem, typical modern headphones are 33 ohms per driver or thereabouts, while LM386 is designed for 8 ohms loads (and at 6 volts can handle 4 ohms, so my 4 headphone load is conservative.
I just came from trying to buy a small tin can, was unlucky, plus the shop was full of people and closing early because of Dec 31; but this week I'll get one, draw/make the PCB and publish it.
Happy 2013
JMFahey
No impedance problem, typical modern headphones are 33 ohms per driver or thereabouts, while LM386 is designed for 8 ohms loads (and at 6 volts can handle 4 ohms, so my 4 headphone load is conservative.
I just came from trying to buy a small tin can, was unlucky, plus the shop was full of people and closing early because of Dec 31; but this week I'll get one, draw/make the PCB and publish it.
Happy 2013
JMFahey
Parallel chips sound a lot closer to higher quality discrete amplifiers. That should work fine with the LM386 too, and send distortion into the ballast resistors, instead of your headphones.
Meanwhile back on topic with power amplifiers. Yes, paralleling can help the power-opamp send crossover distortion into the ballast resistors instead of sending that distortion into the speakers. The improvement from paralleling is elegant.
Meanwhile back on topic with power amplifiers. Yes, paralleling can help the power-opamp send crossover distortion into the ballast resistors instead of sending that distortion into the speakers. The improvement from paralleling is elegant.
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