I have been a forum lurker since about November of last year. Since then I have been slowly accumulating parts to put together a set of BAMTM's. Now that I am finally at the point of putting it all together, I need to decide what I am going to use to run them. I have been doing ALOT of browsing over different options. Gainclones, Class T amps, hifimediy, HLLY, Sure audio, Dayton, Point to Point DIY projects, Lepai amps, etc etc.
Basically I've came to the conclusion that I either want to build a point to point diy amp, or modify a Lepai amp. These seem to be the most cost effective solutions for my priorities. I am not a audiophile in a sense that I can pinpoint the most minute flaws in music like some guys on here can, but I do appreciate a well built and performing stereo system.
I enjoy new age Rock, Hip Hop, and basically all the classics. But something important to me is good bass response.
I am just lost in all of the different projects and options out there. So I was hoping somebody might be able to point me in the right direction between these two options.
Basically I've came to the conclusion that I either want to build a point to point diy amp, or modify a Lepai amp. These seem to be the most cost effective solutions for my priorities. I am not a audiophile in a sense that I can pinpoint the most minute flaws in music like some guys on here can, but I do appreciate a well built and performing stereo system.
I enjoy new age Rock, Hip Hop, and basically all the classics. But something important to me is good bass response.
I am just lost in all of the different projects and options out there. So I was hoping somebody might be able to point me in the right direction between these two options.
For strong bass the cheap T-amps, TA2020 or TA2024 fall short. You can DIY or buy something used from ebay or craigslist to get more power:dollar. I once bought a 100W bookshelf stereo off ebay for a penny with local pickup. It had a broken CD changer so I just pulled the whole CD changer module out. My modified T-amp sounds better within it's much lower volume capability and a DIY chipamp sounds better at 100W, but for "cheap" around the price of a T-amp something like that is the best compromise.
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As far as a DIY point to point goes, are there any designs you would recommend? I have been looking at a lot, but its hard to tell what is a solid design. I thought about following Mick F.'s page on the Gaincard copy found here: Mick Feuerbacher Audio Projects
But he doesn't seem to leave any conclusion on its performance or outcome.
But he doesn't seem to leave any conclusion on its performance or outcome.
You've mentioned point to point a couple of times on this thread, but I'm having trouble understanding what you mean.
Are you talking about a scratch built amp vs. a kit where everything is supplied? A lot of tube amps are point to point, which means there is no PCB involved and I suppose that Solid State "Dead Bug" amps would also fall under this umbrella as well.
(Edit: I see that Feuerbacher's amp mention as a link is actually a "Dead Bug" topography)
Just Wondering.
TerryO
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I had picked it up on the forum as an amp that has its components soldered directly together, versus being organized on to a PCB board. The amp that Mick F. builds in that link has its components soldered "point to point" I guess is how I understood it. Sorry for the confusion. I have just been lurking the threads and found a few mentions of people recommending doing a "point to point" chip amp because they are so simplistic that the pcb isnt necessary.
While a PCB isn't necessary for simple designs, IMO it is still desirable. It (usually) makes the amp more durable, makes it easier to swap components and/or repair later should you ever need to, looks neater/more professional, makes troubleshooting easier including if you ever need someone else to look over the design (pictures), makes mounting components easier, soldering easier, and probably some other benefits that don't come to mind at the moment.
If it were a matter of having to take the time to design it yourself and pay a PCB fab shop to do such a small run of boards, there would be these factors to offset the benefits listed above but since ready made PCBs exist for the more popular chipamp chips, it seems worth the small additional cost once you factor for total project cost and time to DIY.
If it were a matter of having to take the time to design it yourself and pay a PCB fab shop to do such a small run of boards, there would be these factors to offset the benefits listed above but since ready made PCBs exist for the more popular chipamp chips, it seems worth the small additional cost once you factor for total project cost and time to DIY.
One of the oft cited advantages of point to point wiring in tube amps is the ease of modification. For a more complex circuit it seems that a PCB would be advantageous as it's organized and (hopefully) well layed out. For modifying however, it's at a disadvantage unless the board already has optional provisions built into the layout.
Both have their strengths and weaknesses and but I wouldn't say from a functional standpoint that there's any real advantage to a PCB except for compactness and appearence.
Best Regards,
TerryO
^ Depends on what you're changing. When doing a chipamp PTP like the one linked it is very much more of a hassle to change it. That isn't necessarily true of some other designs but also remember if you're already accepting that components aren't on a PCB with PTP, you can still add off-board components with wire when using a PCB even if it means cutting a trace or two to make it work.
Let's consider some common things to change on a chipamp like changing the feedback loop (gain, freq. pass filtering, etc), it's resistors buried in the middle on the amp chip pins in a gainclone PTP, or if capacitors pop or dry out over time, you've got to desolder and bend wires apart at the same time while desoldering a cap from an amp PCB is a walk in the park.
I would not say a PCB is necessarily any more compact, PTP with gainclones gets everything up on the chip pins, otherwise you have unneeded wires and supports for other components, but personally I make PCBs larger than they "need" to be because I don't care if something is 2" x 3" in size when it's going in a case far larger with lots of empty room in it, so long as the low level signal path isn't too convoluted.
Let's consider some common things to change on a chipamp like changing the feedback loop (gain, freq. pass filtering, etc), it's resistors buried in the middle on the amp chip pins in a gainclone PTP, or if capacitors pop or dry out over time, you've got to desolder and bend wires apart at the same time while desoldering a cap from an amp PCB is a walk in the park.
I would not say a PCB is necessarily any more compact, PTP with gainclones gets everything up on the chip pins, otherwise you have unneeded wires and supports for other components, but personally I make PCBs larger than they "need" to be because I don't care if something is 2" x 3" in size when it's going in a case far larger with lots of empty room in it, so long as the low level signal path isn't too convoluted.
^ To each his own opinion, some gainclones have more components, larger components, and I'm fairly sure that while you feel changing components isn't hard, I can change them faster with less risk and less tedious work if it's built on a PCB, than desoldering things wrapped around chip pins.
To put it another way it can be a small cost for PCBs compared to total amp cost (unless you happen to have a broad stockpile of miscellaneous yet relevant parts sitting around) and time spent. I don't see any real negatives to using a (good) PCB even if some feel it isn't necessary.
Also your pictured amp does without a ground plane and no shielding in a wooden case. Some will feel this is ok, but some won't.
To put it another way it can be a small cost for PCBs compared to total amp cost (unless you happen to have a broad stockpile of miscellaneous yet relevant parts sitting around) and time spent. I don't see any real negatives to using a (good) PCB even if some feel it isn't necessary.
Also your pictured amp does without a ground plane and no shielding in a wooden case. Some will feel this is ok, but some won't.
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My latest P2P NIGC;
and the whole thing
Components are very easy to change.
I listened to my previous P2P IGC for 7 years without a problem.
For the amount of components a PCB is ridiculous
I'm fully in agreement and I've built stuff both ways, as I suspect many here have.
BTW: Nice amp!
Best Regards,
TerryO
BTW: Nice amp!
Seconded.
One of the biggest advantages of P-P wiring is the way it forces you to consider each and every ground connection. Speaking of grounds - that looks like you've got a bog-standard mains filter on the mains inlet. Its probably not doing you any favours coz it contains Y-caps inside which will be dumping hash from L and N onto your ground.
^ ?? They're designed to amplify whatever signal you feed them, given a suitable antenna you could make a radio receiver with one.
LM3875 datasheet:
Applications
- Component stereo
- Compact Stereo
- Self Powered Speakers
- Surround Sound Amplifiers
- High End Stereo TVs
Designed to work in cars? They aren't multi-channel BTL chips, have a spec'd "typical" voltage of +-18V (LM3875), not single rail 12V-13.8V, and do not contain any filtering or specialized circuitry specific to ignition noise frequency, nor is there any example or suggestion of automotive use in the datasheet and they are not automotive graded like other National Semi. chips.
You can design a PSU to filter that noise, or pre-filter, and of course boost and split the supply rails, but likewise for other amp chips.
LM3875 datasheet:
Applications
- Component stereo
- Compact Stereo
- Self Powered Speakers
- Surround Sound Amplifiers
- High End Stereo TVs
Designed to work in cars? They aren't multi-channel BTL chips, have a spec'd "typical" voltage of +-18V (LM3875), not single rail 12V-13.8V, and do not contain any filtering or specialized circuitry specific to ignition noise frequency, nor is there any example or suggestion of automotive use in the datasheet and they are not automotive graded like other National Semi. chips.
You can design a PSU to filter that noise, or pre-filter, and of course boost and split the supply rails, but likewise for other amp chips.
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