So far, I've read through about 1/2 of the posts in this thread and am enjoying it. Congrats on your build clog & others! I can't wait to finish my chipamp.com LM3886 right now. It sounds much better than the Adcom 535 I had -- better highs & more clear. I'm building my first amplifier as well 
Now I want to build this amp as well just to compare hah. Maybe I've gotten the addiction? I don't see myself stopping with the LM3886. I could very well end up building several amps then selling off ones I like less. I'm sure if I build the amp well enough I could get my money back on the parts? -- especially since I am reclaiming a case I got from flea market for $5.
Again, congrats, and I look forward to reading the rest of this thread.
Now I want to build this amp as well just to compare hah. Maybe I've gotten the addiction?
I don't see myself stopping with the LM3886. I could very well end up building several amps then selling off ones I like less. I'm sure if I build the amp well enough I could get my money back on the parts? -- especially since I am reclaiming a case I got from flea market for $5.Again, congrats, and I look forward to reading the rest of this thread.
Is anyone selling a complete kit with pcb, semiconductors and these chips? Or do I just buy the board like you did and all the components individually?
Is there one version/package of the LM4780 chip to order? Where should I order it? It's one chip for both channels right? (EDIT: yeah it appears both channels are in the same chip.. just looked at it.. about $10 off ebay)
EDIT #2: I see a lot of various PCB offerings for this LM4780. But should I go with the PCB you went with? It's the best one right? I wonder why the speaker outputs are near the AC inputs of the board though.
EDIT #3: the LM4780 chip is a larger number than the LM3886. But since it is at its end, the LM4870 must be an older chip right? LM3886 are still being made right?
EDIT #4: Would you trust this ebay reseller for the chip? It's $10: http://www.ebay.com/itm/LM4780-Dual...r-IC-2x60W-Amp-HiFi-USA-genuine-/182112239549
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I cannot recommend the 4780 chipamp.
It has to get rid of twice the amount of heat through the heatsink interface.
It will operate at higher temperature and will trigger Spike more often.
I am glad Ti have obsoleted that stupid National release that can only have been aimed at penny pinching commercial assemblers who wanted one less component to be wave soldered to their cut price PCB.
It has to get rid of twice the amount of heat through the heatsink interface.
It will operate at higher temperature and will trigger Spike more often.
I am glad Ti have obsoleted that stupid National release that can only have been aimed at penny pinching commercial assemblers who wanted one less component to be wave soldered to their cut price PCB.
Well it has to get twice the amount of heat because it's two channels right? One big heat sink or two smaller ones, what's the difference? I bought a single 6 inch wide heatsink for my two LM3886 chips the other day and will have Sunday -- hope I didn't make a mistake.
I build it a bit like you plan, powering the modules with DC in to the bridge rectifier on the PA03. This way the delay circuit won't open the relays. I disabled the delay circuit by replacing the counter IC with a small resistor (what jumper I had at hand) between VCC and counter pin 9. Not very elegant but it works for me without pops on start up.
/Torb
Undoubtedly AndrewT is right here but on several occasions I stressed the PA03 at very high levels on my Quad Esl's and for a prolonged time, so far It never triggered the Spike protection.
@Jennifer G AFAIK there is no complete kit available. I bought my board from Peranders in a group buy. See Commercial sector/Group buys. I have no experience with other 4780 boards, so can't advise you here.
Despite the criticisms of the LM4780 heat issues, it still is a very fine sounding chipamp. Actually, the PA03 ... a very outstanding amplifier implementation. Unless you are always listening at ear-splitting levels, or your heatsink is very inadequate, I would say the heat dissipation is a non-issue. I listen almost daily to my PA03 in my shop, and never had a shutdown, or heat issue. However, it's a moot point since the chip has been discontinued - sadly. I was lucky enough to buy a couple extra before that happened though.
I was lucky enough to buy a couple extra before that happened though.Despite the criticisms of the LM4780 heat issues, it still is a very fine sounding chipamp. Actually, the PA03 ... a very outstanding amplifier implementation. Unless you are always listening at ear-splitting levels, or your heatsink is very inadequate, I would say the heat dissipation is a non-issue. I listen almost daily to my PA03 in my shop, and never had a shutdown, or heat issue. However, it's a moot point since the chip has been discontinued - sadly.
How does it compare and contrast to the Chipamp.com LM3886 kit? I think I might have the addiction
i.e. I thought this chipamp lm3886 I bought and am putting together was going to be my first and last Despite the criticisms of the LM4780 heat issues, it still is a very fine sounding chipamp. Actually, the PA03 ... a very outstanding amplifier implementation. Unless you are always listening at ear-splitting levels, or your heatsink is very inadequate, I would say the heat dissipation is a non-issue. I listen almost daily to my PA03 in my shop, and never had a shutdown, or heat issue. However, it's a moot point since the chip has been discontinued - sadly.
https://www.elfa.se/sv/audio-video-...+&page=1&origPos=1&origPageSize=50&simi=91.94
There is some stock at Elfa=)
Despite the criticisms of the LM4780 heat issues, it still is a very fine sounding chipamp. Actually, the PA03 ... a very outstanding amplifier implementation. Unless you are always listening at ear-splitting levels, or your heatsink is very inadequate, I would say the heat dissipation is a non-issue. I listen almost daily to my PA03 in my shop, and never had a shutdown, or heat issue. However, it's a moot point since the chip has been discontinued - sadly.
I agree. I purchased multiple PA03 boards and plenty of spare LM4780. If you do not expect the amplifier to deliver concert-level volumes you have PLENTY of overhead for just about any type of music imaginable. I like the IC and have found it to cause no problems. If your install an adequate heatsink (larger than you think), avoid driving egregiously inefficient speakers with wide impedance variations and hold-off cranking it up past window shattering levels you will have a near world-class amplifier with outstanding design, implementation and PCB design. It is incredibly easy to build, simple easy to troubleshoot and easy to implement.
I would argue the same concerns apply to any amplifier (commercial, DIY or prebuilt bespoke amplifier modules) regardless of price. If I tried to drive my Apogee Duetta II Signatures with my stock NAD 535 I would expect very poor results with overheating, distortion, amplifier damage or catastrophic speaker failure. I wouldn't suggest using the PA03 to drive such a speaker, either. It will overheat, sound great only at levels that wouldn't produce audible sounds from the ribbon panels and likely destroy my PA03 modules. I use a pair of Jeff Rowland Model 5 mono-block amplifiers to drive the speakers and that system produces simply stunning results. That said, I wouldn't drive my B&W monitors or Linn floor standers with the Jeff Rowland mono-blocks but I would drive them with a pair of PA03 modules.
I respect AndrewT for his consistent (if sometimes brash) assistance he provides to the DIY community. He is extremely knowledgable and very proficient in many facets of the DIY audio hobby. However, I do not agree with his opinions on the LM4780. It might be a less expensive option for OEM's and designers but that shouldn't take away from the design of the IC, its easy implementation, ridiculous specifications and stellar sound it provides with minimal and cost-effective BOM. The design offered by the PA03 is exceptional. It delivers stunning results (statistically and empirically) with the added benefit of being easy to build, troubleshoot and implement. Does the LM4780 have issues? Certainly. If your LM4780 is well designed and reverence is paid to its electrical specifications and limitations, it will deliver outstanding results.
I would like to thank those involved in the PA03 from conception to delivery. As an engineer myself I realize the amount of work that goes into a project of this size and to offer up their work to the DIY community for such a small price is wonderful. It might even restore a bit of ones faith in humanity for even the cynical of people. I know. I am a pragmatic and cynical person!
Darren
LM4780: at the moment 860 in stock
LM4780TA/NOPB - TEXAS INSTRUMENTS - Audio Power Amplifier, AB, 2 Channel, 60 W, 20V to 84V, TO-220, 27 Pins | Farnell element14
LM4780TA/NOPB - TEXAS INSTRUMENTS - Audio Power Amplifier, AB, 2 Channel, 60 W, 20V to 84V, TO-220, 27 Pins | Farnell element14
To be honest, I can't tell any significant audible differences in the two chips. That's because the 4780 is simply 2 x 3886s on the a bigger die. There may be certain individuals that can, but their ears are more golden than mine now. Nuances in the sound of either chipset is likely due to the designer's implementation of the external components and choice of PSU. A well designed PSU with plenty of headroom and available current will ward-off the nasties that sagging rails, and hence clipping will induce. You can't get much better than the PA03 design. My 4780 is being driven by a massive amount of iron. Some one mentioned earlier in this, or another thread, that I ought to try it with an SMPS. Never got around to it - yet!How does it compare and contrast to the Chipamp.com LM3886 kit? I think I might have the addiction
But the 4780 sounds so good, why bother? You can find my 4780 build thread here.
Good luck.
Rick
Good to see the chip can still be found.LM4780: at the moment 860 in stock
LM4780TA/NOPB - TEXAS INSTRUMENTS - Audio Power Amplifier, AB, 2 Channel, 60 W, 20V to 84V, TO-220, 27 Pins | Farnell element14
Sorry, can't speak to the Chipamp.com version of the LM3886 amp, as I did not build that one. I used a PCB from Asia, with my own components. However, I have read many positive and favorable comments about the Chipamp amps.How does it compare and contrast to the Chipamp.com LM3886 kit? I think I might have the addiction
Rick
Hi everyone,
after finally obtaining the documentation from a nice fellow, I started studying it.
I'm a bit confused about the input connection in JP2 and JP3, though.
Why all of you guys soldered jumper pins here? Can't you just solder the inputs directly to these points?
Also, in the instructions (page 2) Pavel Dudek explains that if the jumper is connected to "-", the phase is not inverted. And the signal must be connected to the non short circuited pin (in this case, the "+" pin).
However, in the pictures in this thread I didn't see any jumper at this point. Only the signal and ground connections.
Sorry if it's a basic question. It's only my second power amp build. I did build a buffer and a phonostage also, but I still consider myself a newbie here.
Thanks,
VG
after finally obtaining the documentation from a nice fellow, I started studying it.
I'm a bit confused about the input connection in JP2 and JP3, though.
Why all of you guys soldered jumper pins here? Can't you just solder the inputs directly to these points?
Also, in the instructions (page 2) Pavel Dudek explains that if the jumper is connected to "-", the phase is not inverted. And the signal must be connected to the non short circuited pin (in this case, the "+" pin).
However, in the pictures in this thread I didn't see any jumper at this point. Only the signal and ground connections.
Sorry if it's a basic question. It's only my second power amp build. I did build a buffer and a phonostage also, but I still consider myself a newbie here.
Thanks,
VG