So I need an amplifier for a friend. He's currently using a TDA something based 3 channel amplifier I built that runs off of an ATX PSU's 12V rail. Sounds alright but could do better. So I thought I'd make a late christmas/new years present- a less crappy amplifier! 
I'd like to go with a gainclone. Cost matters here, I'm a poor man. Also because they're simple, an I need to get the build done quick.
I've got most of the parts- the case, connectors, multiple transformers to choose from, etc...
Basically, all I need is amp modules now. I'd like to go with an LM3886 or something along the lines, but since bad designs can oscillate and cause all kinds of havoc, I want to check here first to make sure I'm not paying for crap.
Basically, I want an ebay kit because my budget is only around $30 or so.
Here is a list of options, I'd like to know whether any of these are worth giving a shot
1 PC 2 68W Watt LM3886 NE5532 Audio Amplifier Board | eBay
LM3886 NE5532 DC Servo Mounted 2X68W Current Dynamic Feedback Amplifier Board | eBay
2 x Super NS LM3886 LM3886TF Audio Power Amplifier Kit | eBay
2X60W Power Amp LM4780 Fully Built Unit | eBay
Upgrated LM3886 LME49720 Amplifier DIY Kit Speaker Protection 68W Gain Switch | eBay
Audio Power Amplifier LM3886TF Amp Board Kit Rectifier Filter Power DIY Kit | eBay
New MX50 SE 100W 100W 100WX2 Power Amp Kit Stero Amplifier Kit DIY Free | eBay
2pcs 30W Class A High Current Amplifier FET Amp Board Kit | eBay
Last two are solid state designs, which are also options. I'd like to try the class A modules especially.
Since there are more options, feel free to share yours Just remember my budget
Cheers!
-Joel
I'd like to go with a gainclone. Cost matters here, I'm a poor man. Also because they're simple, an I need to get the build done quick.
I've got most of the parts- the case, connectors, multiple transformers to choose from, etc...
Basically, all I need is amp modules now. I'd like to go with an LM3886 or something along the lines, but since bad designs can oscillate and cause all kinds of havoc, I want to check here first to make sure I'm not paying for crap.
Basically, I want an ebay kit because my budget is only around $30 or so.
Here is a list of options, I'd like to know whether any of these are worth giving a shot
1 PC 2 68W Watt LM3886 NE5532 Audio Amplifier Board | eBay
LM3886 NE5532 DC Servo Mounted 2X68W Current Dynamic Feedback Amplifier Board | eBay
2 x Super NS LM3886 LM3886TF Audio Power Amplifier Kit | eBay
2X60W Power Amp LM4780 Fully Built Unit | eBay
Upgrated LM3886 LME49720 Amplifier DIY Kit Speaker Protection 68W Gain Switch | eBay
Audio Power Amplifier LM3886TF Amp Board Kit Rectifier Filter Power DIY Kit | eBay
New MX50 SE 100W 100W 100WX2 Power Amp Kit Stero Amplifier Kit DIY Free | eBay
2pcs 30W Class A High Current Amplifier FET Amp Board Kit | eBay
Last two are solid state designs, which are also options. I'd like to try the class A modules especially.
Since there are more options, feel free to share yours
Just remember my budget Cheers!
-Joel
I know, thanks for the generic answer, bro
I know that some of the kits work and people have build them and used them without their amp or speakers going seppuku.
Out of all the kits, I really like this one: Upgrated LM3886 LME49720 Amplifier DIY Kit Speaker Protection 68W Gain Switch | eBay
Power supply right on the boards, op-amp buffered, speaker protection, you name it. Just needs a transformer and case.
And I really like the class A kit as well, but the circuit seems too simple to be good, I guess...
Found some huge TO-3 hetasinks, so the JLH 1969 is also an option: http://www.ebay.com/itm/1-Pair-Of-J...115?pt=LH_DefaultDomain_0&hash=item3ce6ae24c3
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I have just built the JLH kit you show.
Its a great quality kit and good pcb. Most of the smaller caps are rubycons ,changed the others with good second hand ones I had in stock. The transistors all seem genuine ST and can easily be replaced at a latter stage with mj15003.
I like mine and am just waiting to add speaker protection as it has slight thump on and off
The is a sticky post in forum too about jlh and all mods etc
happy building
Its a great quality kit and good pcb. Most of the smaller caps are rubycons ,changed the others with good second hand ones I had in stock. The transistors all seem genuine ST and can easily be replaced at a latter stage with mj15003.
I like mine and am just waiting to add speaker protection as it has slight thump on and off
The is a sticky post in forum too about jlh and all mods etc
happy building
check these forums for tda729x point to point.
danielwritesback has power level OVER 9000 (see here https://www.youtube.com/watch?v=SiMHTK15Pik)
when building those things, and it would be a very cheap option.
powersupply will be what you are going to pay for a lot of money.
unless you have the guts and crazy enough to build the russian Xformerless psu.
not going to give a link for that, as it is potentialy lethal.
danielwritesback has power level OVER 9000 (see here https://www.youtube.com/watch?v=SiMHTK15Pik)
when building those things, and it would be a very cheap option.
powersupply will be what you are going to pay for a lot of money.
unless you have the guts and crazy enough to build the russian Xformerless psu.
not going to give a link for that, as it is potentialy lethal.
I have built several of the LM3886 cheapo boards for various projects and all have worked well. you won't win stereophiles product of the year with one but if you just need a garage/basement/bedroom amp they worked well enough. my only complaint is that they all use the easy to implement isolated tab version of the 3886 which handles less power.
I most recently built this one
www.ebay.com/itm321448788930
took about 2 weeks to get here. but add a transformer and some jacks and go!
Zc
I most recently built this one
www.ebay.com/itm321448788930
took about 2 weeks to get here. but add a transformer and some jacks and go!
Zc
I know, thanks for the generic answer, bro
I know that some of the kits work and people have build them and used them without their amp or speakers going seppuku.
Out of all the kits, I really like this one: Upgrated LM3886 LME49720 Amplifier DIY Kit Speaker Protection 68W Gain Switch | eBay
Power supply right on the boards, op-amp buffered, speaker protection, you name it. Just needs a transformer and case.
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The price is right! (as it usually is) but note that doesn't include the big ps caps and the cool purple ones:
3 PLS note: The Kit and assembled board does not contain 2pcs Nichicon (10000uF) capasitors
For chemical 10000UF-50V capasitors*2-----need ADD 6USD.
For ELNA-AUDIO capasitors*2----------need ADD 14USD.
I don't like that there's no powersupply caps by the second 3886.
Same thing here, no ps caps beside the 3886s:
60W LM3886TF Sound Audio Amplifier 2 Channel Digital Power Amp | eBay
or item 321448788930
6 USD for the big caps is okay. But what are the small ones? Input coupling? If so, I'll just drop some film caps in there and let's roll If filtering for op-amps, then any electrolytic works.
Small caps near chips? Just solder them onto the pins.
As for the discrete designs, can someone comment on the 30W FET kit? I'd like to try class A, And if I like it, keep using it and give my friend my current amp. Finding a heat sink and transformer is no issue.
If filtering for op-amps, then any electrolytic works.Small caps near chips? Just solder them onto the pins.
As for the discrete designs, can someone comment on the 30W FET kit? I'd like to try class A, And if I like it, keep using it and give my friend my current amp. Finding a heat sink and transformer is no issue.
That's the easy part. The hard part is finding a very close ground to connect the hf ps bypass caps (100nF, leads as short as possible.) Then when you do find a close gnd, it has to be able to handle the hf without polluting other parts of the circuit.
Same thing for the mid-freq (mf) bypass caps (100-1000uF, leads as short as possible.) Except this time the gnd has to be able to handle the larger mf current spikes without polluting other parts of the circuit.
[Same principles as opamp bypassing ... and digital!]
But this is just trying to up the performance closer to the 3886 spec. The 3886 works with even the most haphazard layouts. It just doesn't work as good as it could.
The JLH69 is awesome and the price is again right (especially if you already have the heatsinks)! But if you're just starting out building amps, the chipamp is the perfect place to start. There's a lot of current flowing through the class-A JLH69 and it has no protections like a chipamp (short circuit, thermal, ...)
I'd go with the 3886.
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Okay, so which kit?
Also, how would you compare the JLH kit to the other class A kit? I understand they're a bit of a hassle, but I think it might be worth it for the sound
And what about this one?
New MX50 SE 100W 100W 100WX2 Power Amp Kit Stero Amplifier Kit DIY Free | eBay
Also, how would you compare the JLH kit to the other class A kit? I understand they're a bit of a hassle, but I think it might be worth it for the sound
And what about this one?
New MX50 SE 100W 100W 100WX2 Power Amp Kit Stero Amplifier Kit DIY Free | eBay
If you go for something like this, buy the prebuilt modules, and insist that they test them before shipping to you, otherwise they'll sell you a kit full of crappy components. By the time you put the kit together, you can be sure it won't work. Ask me how I know.
Okay, so which kit?
Also, how would you compare the JLH kit to the other class A kit? I understand they're a bit of a hassle, but I think it might be worth it for the sound
And what about this one?
New MX50 SE 100W 100W 100WX2 Power Amp Kit Stero Amplifier Kit DIY Free | eBay
Dude, I said $30, not $300
I'm in between these kits:
Audio Power Amplifier LM3886TF Amp Board Kit Rectifier Filter Power DIY Kit | eBay
Looks good with good components. Not going to tell them to assemble it, but I will tell them that I want the high quality components as said in the description. It's also nice that it has an external rectifier board with nice caps.
2pcs 30W Class A High Current Amplifier FET Amp Board Kit | eBay
Looks like a simple, yet functional design. Would be a nice entry into the world of class A for me. Requires more components, but I have them.
Latest HiFi 2 0 Stereo Output Digital Power Amplifier TPA3116 50WX2 by WLX New | eBay
Decent looking and reasonably priced. Comes with case and stuff. Just needs a power adapter, easy to find.
I'd like to go for the LM kit, but class A would be interesting and TPA would be easy to implement.
Which one?
Alternative
I purchased and built this:
Generic link to diyAudio Thread LM3886
With good success. I don't know if it made a difference, but I used 1% resistors and found caps that had a low tolerance rating to try to keep specs tight. I didn't test ESR or actual value of the caps as I had no resource for that at the time.
It was tested with a waveform generator and oscilloscope, a Tektronix type 453 (old, but very functional). It has no oscillation.
Oh, and it sounds awesome. Way better than what you can get at a big box. It's driving a set of JBL LX300, which aren't the best speakers in the world, but it still delivers a good sound stage and detail. Bass could be more, but that's a deficit that can be assigned to the bookshelf style speakers that come packed in a box. I.e. these speakers have always had that issue.
There needs to be thanks for the success of the above project, however, to the diyAudio community for their help through the basics. I'm still learning.
I've got PCBs for the F5 and a basic gainclone LM3886 that included the power supply and two channels. I haven't built them, yet, but will do so in the near future.
The F5 PCB from fleabay requires slightly different resistor values at some points from the schematic provided by Pass Labs. I haven't done a thorough one to one comparison to ensure that the actual circuit was the same, but it seemed at first glance to be on target. If the tracing is the same as Pass Labs, then I don't see any harm in using the component values from Pass.
Anyway, it's easy to knock what you haven't done or experienced. I figured that it was easier to throw a hundred bucks or so at an amp that I put together and troubleshooted if there were sound issues than to spend 600 on a big box amp. The sound quality that it gives is by far better than anything that I've heard at a BB, even in their "bragnolia" listening room.
Good luck, and post with questions. If my limited experience can help, I'll do so, but there are some wizards that populate this forum and I'll always bow to their expertise.
I purchased and built this:
Generic link to diyAudio Thread LM3886
With good success. I don't know if it made a difference, but I used 1% resistors and found caps that had a low tolerance rating to try to keep specs tight. I didn't test ESR or actual value of the caps as I had no resource for that at the time.
It was tested with a waveform generator and oscilloscope, a Tektronix type 453 (old, but very functional). It has no oscillation.
Oh, and it sounds awesome. Way better than what you can get at a big box. It's driving a set of JBL LX300, which aren't the best speakers in the world, but it still delivers a good sound stage and detail. Bass could be more, but that's a deficit that can be assigned to the bookshelf style speakers that come packed in a box. I.e. these speakers have always had that issue.
There needs to be thanks for the success of the above project, however, to the diyAudio community for their help through the basics. I'm still learning.
I've got PCBs for the F5 and a basic gainclone LM3886 that included the power supply and two channels. I haven't built them, yet, but will do so in the near future.
The F5 PCB from fleabay requires slightly different resistor values at some points from the schematic provided by Pass Labs. I haven't done a thorough one to one comparison to ensure that the actual circuit was the same, but it seemed at first glance to be on target. If the tracing is the same as Pass Labs, then I don't see any harm in using the component values from Pass.
Anyway, it's easy to knock what you haven't done or experienced. I figured that it was easier to throw a hundred bucks or so at an amp that I put together and troubleshooted if there were sound issues than to spend 600 on a big box amp. The sound quality that it gives is by far better than anything that I've heard at a BB, even in their "bragnolia" listening room.
Good luck, and post with questions. If my limited experience can help, I'll do so, but there are some wizards that populate this forum and I'll always bow to their expertise.
I recommend trying cheap PCBs where the warranty is either not offered or is dubious.
Poor quality PCBs don't survive changes/repairs as well as commercial quality product. But they generally perform as well at first assembly.
I don't recommend cheap amplifier kits without an effective warranty.
In particular return postage paid by the Seller when the kit is proved to be "not as described".
The main way to reduce the cost of a kit is to use ultra cheap fake components.
These do no one any good except for the faker, who will resort to any method to make an illegal profit.
Poor quality PCBs don't survive changes/repairs as well as commercial quality product. But they generally perform as well at first assembly.
I don't recommend cheap amplifier kits without an effective warranty.
In particular return postage paid by the Seller when the kit is proved to be "not as described".
The main way to reduce the cost of a kit is to use ultra cheap fake components.
These do no one any good except for the faker, who will resort to any method to make an illegal profit.
The kits that I've received are good quality. As a matter of fact, the tracings and adherence to the boards are better than a lot I've seen. Now, I haven't taken apart a McIntosh or a Bryston, but they certainly fair better than the BB stuff. Further, I've had no problems in desoldering and replacing. None. As a matter of fact, some of the worst tracings that I've seen come from car computers - Mitsubitchy and Frod come to mind.
I've never bought a "kit," I've sourced only PCBs, so I can't speak to the legitimacy of the components. The whole reason that I've avoided kits is the reason that Andrew has mentioned. I've used Mouser, Digikey, Parts Express, etc. to limit the introduction of crappy components.
Still, the expense for sourcing the components through trusted e-tailers, construction and potential diagnostics isn't such a big risk, unless you have only 100 dollars to spend on this project and will never put any money toward any other amp again.
For me, the fun was the risk of getting circuit that was faulty, diagnosing any errors, then learning how to fix it. I'm still learning about this stuff, and this was a good starting place.
I think I'll go for the first kit. PCBs look good, everything needed is included, etc... They claim good quality components in the description, and I will make sure to point out to them that I want those good components.
And even if I get fakes, so what? A fake LM chip is going to have inferior performance probably, but that's no big concern, since I won't be using it and my friend is no audiophile. Also his speakers, Beag HOX41 are not the most revealing, so micro details in music, exceptional THD levels, etc... don't matter.
If the caps are fakes, then my local electronics supplier sells high quality Panasonic FM caps for real cheap, and a set of caps for that circuit would cost (excluding power caps) less than a few bucks. Connectors on the boards seem decent also. Not sure if you can fake resistors, so again, no big deal.
This really isn't supposed to be an audiophile amp. What my friend is really looking for is a decent, above mediocre sounding amplifier that has good bass and overall clear sound and enough power to push the Beags. And I also have all the necessary components to finish the amp: enclosure (Yamaha receiver chassis), power transformer (~700VA), connectors (RCA and binding posts), pots, switches, wires (all cost a total of less than 5$)
All I need is the modules and power supply board, which is exactly what this kit contains. So I think I've made my choice
Since I have not ordered it yet and it will be a few days until I do, I'm still open to suggestions. But please, KEEP IT CHEAP! I'm not made of money, you know.
A huge thank you to everyone who replied and thanks for you recommendations!
And even if I get fakes, so what? A fake LM chip is going to have inferior performance probably, but that's no big concern, since I won't be using it and my friend is no audiophile. Also his speakers, Beag HOX41 are not the most revealing, so micro details in music, exceptional THD levels, etc... don't matter.
If the caps are fakes, then my local electronics supplier sells high quality Panasonic FM caps for real cheap, and a set of caps for that circuit would cost (excluding power caps) less than a few bucks. Connectors on the boards seem decent also. Not sure if you can fake resistors, so again, no big deal.
This really isn't supposed to be an audiophile amp. What my friend is really looking for is a decent, above mediocre sounding amplifier that has good bass and overall clear sound and enough power to push the Beags. And I also have all the necessary components to finish the amp: enclosure (Yamaha receiver chassis), power transformer (~700VA), connectors (RCA and binding posts), pots, switches, wires (all cost a total of less than 5$)
All I need is the modules and power supply board, which is exactly what this kit contains. So I think I've made my choice
Since I have not ordered it yet and it will be a few days until I do, I'm still open to suggestions. But please, KEEP IT CHEAP! I'm not made of money, you know.
A huge thank you to everyone who replied and thanks for you recommendations!
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