Hello everyone,
This is my first post, and I apologize in advance for the wall of text.
If I can build an amp for $200, that sounds at least as good as my mid-range Yamaha receiver but also runs this particular 5 ohm nominal (dips to 2.8 ohms) speaker that I've had my eye on then that would be fantastic. I'll be running the speakers full range without a sub, so it'll need a lot of juice.
Components are limited in variety where I live but I can order stuff from abroad. And my technical ability is limited. My only credentials are that I've assembled my own gaming PC. Labor is very cheap so I can get someone to solder and drill and whatever as it'll only cost 5% of the cost of getting my own tools.
Would it even be remotely feasible for me to pursue something like this in your opinion. If you give me the green light I'll dive deep and see the project to the end that's for sure. Just point me to online resources, I'll teach myself everything.
-DIYhopeful
This is my first post, and I apologize in advance for the wall of text.
If I can build an amp for $200, that sounds at least as good as my mid-range Yamaha receiver but also runs this particular 5 ohm nominal (dips to 2.8 ohms) speaker that I've had my eye on then that would be fantastic. I'll be running the speakers full range without a sub, so it'll need a lot of juice.
Components are limited in variety where I live but I can order stuff from abroad. And my technical ability is limited. My only credentials are that I've assembled my own gaming PC. Labor is very cheap so I can get someone to solder and drill and whatever as it'll only cost 5% of the cost of getting my own tools.
Would it even be remotely feasible for me to pursue something like this in your opinion. If you give me the green light I'll dive deep and see the project to the end that's for sure. Just point me to online resources, I'll teach myself everything.
-DIYhopeful
Can you get some equipment to dismantle for parts? That would be the best first way to build an amp.
Do not spend much money on a first build, because it will take several tries to get something worth keeping.
A nice chassis, transformer, and heat sink are gold. A used, nonworking (heavy) amp/receiver would be useful.
Hello, welcome.
That is quite a tight budget, but where there's a will there's a wayDo you not want to learn to solder? That's where most of the fun is
Not really
but I could if need be.Actually yes, I bought a working Onkyo PA-C50 amplifier (part of a set of cassette player, CD player, radio and equalizer) for $26, and there were 2 more of the same model. There's a market nearby which imports old electronics from Japan. Most of them work but I could look for a dead unit for cheaper. I actually found some ancient mid to high end Japanese gear. Including Victor amps, Kenwood amps, Sansui, Yamaha, one labeled Trio. Some of them had wood panels on the sides and looked expensive. These were mostly priced ~$50 but I was hesitant because I do not have the skill or tools to repair them, nor is there someone in my city who could repair them.
I took pictures as well to look up the model names when I got home. Sansui AU-V7000, Kenwood A-7000, Yamaha AVX-1000 DSP, Yamaha AVX-2200 DSP, Trio KA-5300 and a Victor (JVC?) JA-S5. I looked them up but they had very little power ratings so I discarded the idea of buying these but maybe I'm wrong?
I could get a dead unit like the ones mentioned above and scavenge the transformer, chassis and heatsink and potentially save some money.
As scottjoplin said, I could do the solder. But a kit sounds good as well. Whatever fits the bill. I'm just looking at the best way out.
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It might help a lot to note where you are. There's folks from all over here, some may know your market, or even live near and have excess projects.
Foo on wood. You want a Power Amp. You want WEIGHT. Specifically a hefty power transformer. You want heatsinks also, but if the PT is generous the sinks will be fine. Most of the rest of the amplifier, unless you are sharper than those Japanese brokers, will be bad or end-of-life, but the iron is usually good and worth its weight.
Foo on wood. You want a Power Amp. You want WEIGHT. Specifically a hefty power transformer. You want heatsinks also, but if the PT is generous the sinks will be fine. Most of the rest of the amplifier, unless you are sharper than those Japanese brokers, will be bad or end-of-life, but the iron is usually good and worth its weight.
Here in the states the best deal is blown up PA amps for repair or parts on e-bay or craigslist (local free ads for local pickup). They are black and look like garbage, but the ones containing transformers are low priced because touring bands do not want to carry that much weight. Brands considered reliable and repairable include Peavey, Crown, QSC, Yamaha. I picked up a Peavey PV-4c for $20 plus $28 UPS, put $40 of output transistors, $16 worth of rail caps and use it 8-16 hours a day on my television. I picked up a PV-1.3k for $55 and brought home on the bus for $2, but it took 128 new parts including $90 for 20 output transistors, $30 for drivers predrivers and op amps, and $25 for new electrolytic caps. But that was more powerful than you need. The PV-4c would be perfect for your needs.
I picked up a Peavey 75 w mono mixer amp for $63 this month free freight, to mix two keyboards and a organ into the organs speaker. Original organ amp was 30 w, no mixer, which works and will amplify my radio out at my summer camp..
Switcher supply PA amps are more dangerous to repair, and although I've done it, I do not recommend those to a newby.
You'll need a $30 dvm and a $30 analog voltmeter with 10 vac and 50 vac scales (2 vac and 20 vac are better if you can find one). You need a package of insulated alligator clip leads to take measurements without using both hands. You'll need a .047 uf 400 v cap to put in series with the probe on the analog voltmeter. DVM average over 2-4 seconds on AC signals, misinterpret oscillation as music signals, and lie a lot about music that is not at 50-60 hz. Analog voltmeters are more durable than a scope, and are not limited to 80 v as cheap scopes are.
You'll need a 12 v power supply, wall transformer, to test parts for leakage at elevated voltage.
You'll need a light bulb box with a 100 w incandescent bulb in series with the AC to test low power amps, and the PV-1.3k I needed a 1200 w room heater element(resistor) to put in series with the transformer to test it at low energy. Alternate devices for the low power resistor can be single cup boilers for tea. These need to be located in a grounded box with a circuit breaker, or at least a fuse.
You'll need a 35-60 w soldering iron, needle nose & slip joint pliers, flat & phillips screwdrivers, diagonal cutters, wire strippers, a solder sucker bulb or device.
Actual blown up hifi amps like dynaco, McIntosh, Parasound, Mark Levinson, go for a lot more money and aren't worth it IMHO. But the Peavey's typically have 0.02% HD at full power. And the idle bias circuit can be modified to get low wattage due to crossover distortion down.
When you find a model you think might work, search on here or on the internet in general for the owner's manual to read the specifications.
Other than that, finding oddball voltage surplus transformers can be remunerative. I scored some 44 vac 3 amp ones for $10 each on e-bay three months ago. You want something like 36 to 60 v for the 2.5 ohm circuit. You'll need at least 2 pair output transistors, maybe 3, per channel. 3 A transformers, you'd need one for each channel. Blown up flat TV's also have 60 v switcher supplies in them, a couple of amps, and the samsung I salvaged off the curb the obvious problem were the input capacitors were blown. It was full of TO-3p heat sinks, also.
The diyaudio kit for sale in the top banner would do what you want, honeybadger, but two channels may be a little over your budget. Rake some leaves or shovel some snow or something IMHO. You need a metal case to keep the RF from radio stations out. Split supply amps you need a protection circuit to not burn your speakers if a solder joint pops loose and produces DC on the output. Single supply amps have a $3 speaker capacitor that does that, I recommend those for diy builders. Most PA amps nave some sort of speaker protection circuit, often blown up before you buy it.
Safety warning to newbies: Voltage over 24 that crosses your heart can stop it: use one hand at a time when the power is on. transistors and capacitors can explode, wear safety glasses. Stored energy at 1 v can burn your flesh to charcoal, wear no jewelry on fingers, hands, or neck. Touch no metal until you've measured it as <1 v to ground. Don't work alone, and don't work distracted by media or visitors. Warning heat sink grease is poisonous, don't put fingers in mouth or eyes until washed off.
Have fun with the hobby. Scrounging up the supplies without paying retail is like a treasure hunt. BTW, output transistors and large rail capacitors are best bought at authorized distributors like farnell, digikey, mouser, RS, some german names I can't remember. Substitutions of fake parts for real ones happens at the border in some countries, so it is best to find a distributor that operates in your country and manages the customs process themselves.
I picked up a Peavey 75 w mono mixer amp for $63 this month free freight, to mix two keyboards and a organ into the organs speaker. Original organ amp was 30 w, no mixer, which works and will amplify my radio out at my summer camp..
Switcher supply PA amps are more dangerous to repair, and although I've done it, I do not recommend those to a newby.
You'll need a $30 dvm and a $30 analog voltmeter with 10 vac and 50 vac scales (2 vac and 20 vac are better if you can find one). You need a package of insulated alligator clip leads to take measurements without using both hands. You'll need a .047 uf 400 v cap to put in series with the probe on the analog voltmeter. DVM average over 2-4 seconds on AC signals, misinterpret oscillation as music signals, and lie a lot about music that is not at 50-60 hz. Analog voltmeters are more durable than a scope, and are not limited to 80 v as cheap scopes are.
You'll need a 12 v power supply, wall transformer, to test parts for leakage at elevated voltage.
You'll need a light bulb box with a 100 w incandescent bulb in series with the AC to test low power amps, and the PV-1.3k I needed a 1200 w room heater element(resistor) to put in series with the transformer to test it at low energy. Alternate devices for the low power resistor can be single cup boilers for tea. These need to be located in a grounded box with a circuit breaker, or at least a fuse.
You'll need a 35-60 w soldering iron, needle nose & slip joint pliers, flat & phillips screwdrivers, diagonal cutters, wire strippers, a solder sucker bulb or device.
Actual blown up hifi amps like dynaco, McIntosh, Parasound, Mark Levinson, go for a lot more money and aren't worth it IMHO. But the Peavey's typically have 0.02% HD at full power. And the idle bias circuit can be modified to get low wattage due to crossover distortion down.
When you find a model you think might work, search on here or on the internet in general for the owner's manual to read the specifications.
Other than that, finding oddball voltage surplus transformers can be remunerative. I scored some 44 vac 3 amp ones for $10 each on e-bay three months ago. You want something like 36 to 60 v for the 2.5 ohm circuit. You'll need at least 2 pair output transistors, maybe 3, per channel. 3 A transformers, you'd need one for each channel. Blown up flat TV's also have 60 v switcher supplies in them, a couple of amps, and the samsung I salvaged off the curb the obvious problem were the input capacitors were blown. It was full of TO-3p heat sinks, also.
The diyaudio kit for sale in the top banner would do what you want, honeybadger, but two channels may be a little over your budget. Rake some leaves or shovel some snow or something IMHO. You need a metal case to keep the RF from radio stations out. Split supply amps you need a protection circuit to not burn your speakers if a solder joint pops loose and produces DC on the output. Single supply amps have a $3 speaker capacitor that does that, I recommend those for diy builders. Most PA amps nave some sort of speaker protection circuit, often blown up before you buy it.
Safety warning to newbies: Voltage over 24 that crosses your heart can stop it: use one hand at a time when the power is on. transistors and capacitors can explode, wear safety glasses. Stored energy at 1 v can burn your flesh to charcoal, wear no jewelry on fingers, hands, or neck. Touch no metal until you've measured it as <1 v to ground. Don't work alone, and don't work distracted by media or visitors. Warning heat sink grease is poisonous, don't put fingers in mouth or eyes until washed off.
Have fun with the hobby. Scrounging up the supplies without paying retail is like a treasure hunt. BTW, output transistors and large rail capacitors are best bought at authorized distributors like farnell, digikey, mouser, RS, some german names I can't remember. Substitutions of fake parts for real ones happens at the border in some countries, so it is best to find a distributor that operates in your country and manages the customs process themselves.
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