Need help to select DIY amplifier.

Hi I have searched the internet thin, in a try to try to answer my own question, but often do I just stumble upon a lot of marketing, snake oil or articles that do not quiet answer my question.


My budget and my goal do in no way allow me to just go and buy some of the really high end amplifiers, so I want to build my own and be able to do it step by step, until I am happy with the result.
On the other side do I also lack the knowledge of just start designing, and I know that some of you, have made amplifiers who easily kicks the main stream brands. :)


What I am looking for is what Densen called "the air guitar effect" or maybe better to describe it like this: You know that sometimes you just stumble upon a system, where even you less preferred music, just for some reason, makes you enjoy it, you suddenly want to hear some of that awful music you bought by a big mistake, and you enjoy it.
I'd rather sacrifise minute details or bass below the center of earth, then compromise on the "music love". Also the amount of wattage, power or anything else, is second, first find the perfect sound, then the data.



Do any of you, know a class A/B project, that needs my goal?
 
A good audio amp won't do anything but reproduce accurately. Emotional response is in your head, not the electronics, despite what a lot of people seem to believe. Turning up the volume will always improve the perceived sound quality!

Good room acoustics and speakers are the best places to look for improving sound quality, most good SS amps are transparent and have no effect on your experience if they are working, have a flat response (trivial), low enough distortion (not hard), and adequate power handling for your speakers in the listening space.

The thread on the Honeybadger will get you started on an excellent class-B design, there are simpler and cheaper alternatives of course.

You might want to checkout JohnAudioTech's video series on YouTube about designing/building an audio amp: YouTube
 
A good audio amp won't do anything but reproduce accurately.
Good room acoustics and speakers are the best places to look for improving sound quality, most good SS amps are transparent and have no effect on your experience if they are working, have a flat response (trivial), low enough distortion (not hard), and adequate power handling for your speakers in the listening space.
I spent $1000 on my last pair of speakers, some Peavey SP2-XT. Sort of Klipsch LaScala without 14.5-20 khz which I can't hear anyway. Look at the HD specs! at 1 W which is where I use them. Most speakers don't even have +-3 db frequency specs, just some unspecified response that may be +-10 db for all you know.
I spent $40000 on a house with a 14'x33'x11' room, shaped like Wein Philharmonica hall, on a lot where the nearest neighbor is 40' away and can't hear me play music at 3 AM. I've got enough couches, carpet, book/record shelves, organ/pianos to break up the standing waves and those have a lot more utility than acoustic foam on the walls.
I spent $100 on the amp. $50 burnt up ST120, 4 new output transistors, an AX6 board to replace one PC14 that had been patched too many times, a djoffe bias board to make the surviving PC14 sound good. New regulator board.
Better sounding is an $80 amp, a PV-4c I paid $32 with freight (amp for parts or repair), 8 output transistors, 4 rail caps and some more heat sink fins.
If you HAVE to build it from scratch, a honey badger is great but the case transformer/switcher supply, heat sinks, jacks, controls, circuit breaker blah blah blah will cost you a lot more than $80.
I learned as much repairing old amps as I would IMHO building a kit. Plus I don't need a state of the art computer to run sim software or PC layout software. I don't need to keep up a printer that would need a new $40 cartridge every 8 weeks since I don't use one enough to keep the ink flowing.
Ebay is a little sparse on amps for parts or repair this time of year with everybody indoors. Look in May-August when everybody is in a boat or at the pool. Or cruise pawn shops or musician's resale shops. Don't buy a dog like a SWTC Tiger (unstable) or a Behringer (no schematics, not much help available). Find something attractively priced, check out the opinions on here before purchase. Smell the transformer at $100 up, a burnt one doesn't save you any money.
Now that flat undistorted response is reliable, I'm fiddling a bit with tone controls and reverb on certain tracks. I hate Mozart imitators that were forgotton because they weren't any good, and most string quartets, but if that is what WUOL-FM is playing, a little reverb helps the medicine go down. Digitech Studio V4 Quad effects box came with the SP2's, need a pot. Peavey Q215 graphic equalizer came with the SP2's, dead channel was caused by a bad solder joint. CS800s came with the SP'2s, burnt input resistors cost $.01, new PS caps $20, haven't beat the channel dropping out due to a bad punchblock (probably) yet.
Happy shopping, & maybe building.
Have fun with the hobby.
 
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Do any of you, know a class A/B project, that needs my goal?

Hello Fred...
Amplifier design and implementation is easy ... getting it right is hard.

Before you get in too deeply you should spend a bit of time studying up on the theory behind it all. Follow the link in my signature... just start reading, they take you through it in such a way that each new lesson brings you closer.

A good amplifier has no voice of it's own. As Mark points out it's goal is accuracy, whatever you feed it comes out the other end as a bigger, exact copy of what went in. Low distortion, level frequency response, stability and current capacity are the main goals.

The air guitar effect (or in my case the air-drummer effect) is a function of sources, speakers and rooms... everything else is just relaying electrical impulses. When it's right, it's pretty hard to just sit and listen.

As for where to start... look for small chip amp kits, the 10 and 20 watt stuff. This will let you get your feet wet before you build your big amp and black out half of Northern Europe. It may seem unnecessary but first time builders taking on complex projects seldom succeed... practice is an essential step.

I wish you the best with your ambitions. Electronics is a very rewarding hobby (or profession) and audio is just the bees knees....
 
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Sadface

Member
2012-01-21 10:57 pm
Auckland
As for where to start... look for small chip amp kits, the 10 and 20 watt stuff. This will let you get your feet wet before you build your big amp and black out half of Northern Europe. It may seem unnecessary but first time builders taking on complex projects seldom succeed... practice is an essential step.


I would agree,

New 20W LM1875T Mono Channel Stereo Audio HIFI Amplifier Board Module DIY Kit | eBay
This would be a great place to start. These LM1875 boards can put out some impressively good sound for their low cost. Especially if you replace some of the parts that come with the kit for name brand components such as the capacitors. If you can stretch the budget, you could buy half a dozen sets and experiment with iterative component changes to see what things do.

This has been suggested as a suitable power supply for starters.
dual group output +-24V and DC12V 300W power board MX50 L20 audio amplifier board power supply instead toroidal transformer-in AC/DC Adapters from Consumer Electronics on AliExpress

Here is a good thread for more information.
eBay mono LM1875 kit

Simple and high performance for the costs involved.

On a side note, often the costs of chassis, heatsinks, sockets and switches etc can be a larger chunk of the build cost than you might think. I often keep an eye on our local auction website for cheap/faulty amps/vcr players etc simply for salvage chassis, heatsinks and transformers etc.
 
Happy shopping, & maybe building.
Have fun with the hobby.
Thank you a lot for that great and interesting answer! :)


Hello Fred...
Amplifier design and implementation is easy ... getting it right is hard.

Before you get in too deeply you should spend a bit of time studying up on the theory behind it all. Follow the link in my signature... just start reading, they take you through it in such a way that each new lesson brings you closer.
You are completely correct but I am not intending to design, calculate, build and test. My idea were to grab a project from one of you geniuses, among all these forum posts, am I sure there have to be some diamonds. So I am most looking for a tread where someone have made something super special. Just take the Lightspeed passive preamp, it's something no other have ever matched but is right here on this great forum. So the hope of an amplifier here, should not be impossible:)



A good amplifier has no voice of it's own. As Mark points out it's goal is accuracy, whatever you feed it comes out the other end as a bigger, exact copy of what went in. Low distortion, level frequency response, stability and current capacity are the main goals.
I think it's a discussion many have every day. If it were so easy, would you never have the BBC-dip in speakers or tube-amps. It would also be super easy to design the perfect amplifier, just measure it to be flat and there you go:)

The air guitar effect (or in my case the air-drummer effect) is a function of sources, speakers and rooms... everything else is just relaying electrical impulses. When it's right, it's pretty hard to just sit and listen.
Exactly, and that is what I am looking fore. It would be almost insane for me to expect to be able to start from scratch, reading basic electronic and a year later, build the best "air-drummer effect". But there have to be some designs somewhere, either here, an old schematic out there or something else.

As for where to start... look for small chip amp kits, the 10 and 20 watt stuff. This will let you get your feet wet before you build your big amp and black out half of Northern Europe. It may seem unnecessary but first time builders taking on complex projects seldom succeed... practice is an essential step.

I wish you the best with your ambitions. Electronics is a very rewarding hobby (or profession) and audio is just the bees knees....
Exactly, so no start from scratch for me, first just take a design and then build it, while learning:)
 
You are completely correct but I am not intending to design, calculate, build and test. My idea were to grab a project from one of you geniuses, among all these forum posts, am I sure there have to be some diamonds.
...
Exactly, so no start from scratch for me, first just take a design and then build it, while learning:)

I think you misunderstand. You don't really need to study theory to buy pre-made boards and parts then solder them up and get a working amp.

You need it for when you do that and the amp does not work . That is when an understanding of theory and why things are done in certain ways will prove to be invaluable to you. The alternative is to scrap your project and start over.

A friend of mine who's an auto mechanic summed it up pretty well. "I fix cars. When the car works you don't need my skills. But when it doesn't you will end up at my shop."

If you don't think this is an issue take a look at the huge number of threads where people come here asking for help or advice on their DIY projects that haven't worked out as planned. Look who's helping them... yep, the ones who took the time to study the theory.

Once again...
You are not going to get the toe tapping effect you seek from an amplifier. Trust me, it just won't happen.

In fact, if you took 20 of the best quality amplifiers, lined them all up with switching and level matched them to play at the same volume... you'd be very hard pressed to know which one you were actually listening to. Yes, the good ones actually do all sound pretty much the same.

The effect you seek is in the domain of room acoustics, speakers, and your source recordings. The job of the electronics is to faithfully reproduce what is on your your source recording, converting it's data to a waveform that is useful to a speaker. The speaker's job, as a transducer, is to get that waveform off the wires and into the air as faithfully as possible and the room is going to affect that sound transmission rather noticeably.

Some of the most fun I've had with music has come from systems that most would consider mediocre at best... but with really good source recordings. On vinyl, tape or digital doesn't matter. What matters is the quality of the sound mix and the performance itself. The recording is merely a medium to distribute that effort. Even the world's best amplifier can not fix a bad recording, crappy speakers or a noisy room.

The BBC Dip is not what you seem to think it is. It was originally a gap in the crossover frequencies of the woofer and tweeter, intended to address a phasing problem they could not solve. Trust me it's been solved a long time ago and speakers are the better for it.

Tube amps are no panacea either. Before solid state and chips, there was only tubes. They were inefficient, prone to all kinds of strange problems and often very high in distortion with poor frequency response. Granted today's designs are better but they still remain a throwback to a time before "HiFi" even existed.

But, don't be discouraged. Many people come to this hobby with some pretty strange expectations of what can and can't be done... or what should or should not be done. If they are sufficiently interested they will spend the time and make the effort to learn and the ones who do are most often very glad they did. These are the people who stay with it and develop the very projects you are looking to try.
 
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amplidude

Member
2016-02-04 3:20 pm
Also take in consideration how much power you really need, if you're speakers are high efficient I would go for low power ab or pure a , a jlh for example.
All amplifiers are made by compromise, low power, low distortion.
Am building greg ball ska150 now, and I really feel it's a amp I'm gonna love.
 

phase

Member
2004-10-04 11:59 pm
I would spend lots of time reading and researching, mostly on this site to begin to discover the ins and outs of this great hobby.
You’ll find that it’s only a re-creation of a musical performance, is not ALL about accuracy, but balancing harmonics as well. Another thing to consider is that there are many different backgrounds, and viewpoints that make it all work here on this site.

The chip amps are a great way to start for sure, as can be DACs, headphone amps, but definitely research before buying, as many diy kits and assembled boards have their, uh, trade offs(tragic errors).
As for power, it can depend on other things like expectations, size of room, speakers, but overall, for me, around 100 watts is plenty. Less can be just as rewarding however, and much easier to start small to appreciate the effects of a power supply, etc.

A decent multi-meter, a low amperage soldering iron, and did I mention research?
 
@phase ... you forgot the Oscilloscope... an essential tool on any electronics workbench.
After 61 years in the electronics hobby, I finally have a problem subtle enough to make it worth the 20 hours it took to fix the sweep on the B&K 2120 scope. Hours & hours were spent scraping glue off boards & controls to get one out. OTOH I could have put a 100x gain circuit in front of my Simpson 266XLPM meter and carried on.
Note analog TV's are a different animal, and hideously obsolete.
 
Scott ... if an amplifier has it's own characteristic sound it is anything but a "great amp". In fact, it doesn't even qualify as "HiFi" which by definition speaks to a high level of accuracy in reproducing the signals handed to it. By changing or modifying the signal it entirely rules itself out.

On the off chance you are referring to some bizarre contrivance that talks to you... Naaaa... not funny.
 
Pass Labs amps are considered great amps, a number of them have quite high distortion, but it appears distortion isn't necessarily a very good measure of the quality of the perceived sound, and some people quite like a bit of second harmonic distortion. What could well be more important, even in hi-fi terms, is having a large bandwidth.

The OP might like to check out the ACA from Nelson Pass
 
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AllenB

Moderator
Paid Member
2008-10-18 11:31 am

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Wow you are all great, I'll try to reply to you all in this one long post:)


I think you misunderstand. You don't really need to study theory to buy pre-made boards and parts then solder them up and get a working amp.

You need it for when you do that and the amp does not work . That is when an understanding of theory and why things are done in certain ways will prove to be invaluable to you. The alternative is to scrap your project and start over.
Yes sorry, I did clearly misunderstood you but thanks for trying again!
I have seen great projects on this forum, the type where you just have to get the board made and then solder the components in the right places. At that niveau do I think I can manage to troubleshoot and get a usable board:)


So in short, if somebody has a "silver platter" project, where I just have to get a board made and place the components, I think I can manage.


A friend of mine who's an auto mechanic summed it up pretty well. "I fix cars. When the car works you don't need my skills. But when it doesn't you will end up at my shop."

If you don't think this is an issue take a look at the huge number of threads where people come here asking for help or advice on their DIY projects that haven't worked out as planned. Look who's helping them... yep, the ones who took the time to study the theory.
LOL how right you are, I can't tell you how many times I ore one of my employees have been out to repair a computer, because a "don't know sh*t" had played expert. It do take a lot of knowledge, unless you just have to follow a "put C1 there, solder here".



Once again...
You are not going to get the toe tapping effect you seek from an amplifier. Trust me, it just won't happen.

In fact, if you took 20 of the best quality amplifiers, lined them all up with switching and level matched them to play at the same volume... you'd be very hard pressed to know which one you were actually listening to. Yes, the good ones actually do all sound pretty much the same.

The effect you seek is in the domain of room acoustics, speakers, and your source recordings. The job of the electronics is to faithfully reproduce what is on your your source recording, converting it's data to a waveform that is useful to a speaker. The speaker's job, as a transducer, is to get that waveform off the wires and into the air as faithfully as possible and the room is going to affect that sound transmission rather noticeably.

Some of the most fun I've had with music has come from systems that most would consider mediocre at best... but with really good source recordings. On vinyl, tape or digital doesn't matter. What matters is the quality of the sound mix and the performance itself. The recording is merely a medium to distribute that effort. Even the world's best amplifier can not fix a bad recording, crappy speakers or a noisy room.
Yes you are right in so many ways. I have heard gear that costs a kidney from every member in a large family, that I would not own, due to lack of musicality, and I have heard others for nearly "nothing" that would be allowed to sleep under my pillow:)


On the other hand do I think there are several philosophies about what the systems job is:) I know that for some do details matter, if the recording contains a fly farting 50 ft away, they want to be able to determine the flys gender by the fart sound alone.
Other don't care about anything, and is living happily by listening to there clock radio.




My idea for a great system, is if I can put anything on the system and like it, good/bad recording, my music "style" or the opposite.



The BBC Dip is not what you seem to think it is. It was originally a gap in the crossover frequencies of the woofer and tweeter, intended to address a phasing problem they could not solve. Trust me it's been solved a long time ago and speakers are the better for it.
Okay I thought it were because BBC did order the perfect liniar speakers and did get it, but they sounded awefull and unnatural, so they had to add a "flaw" in the liniarity, a "BBC-dip" to get the sound right.

Tube amps are no panacea either. Before solid state and chips, there was only tubes. They were inefficient, prone to all kinds of strange problems and often very high in distortion with poor frequency response. Granted today's designs are better but they still remain a throwback to a time before "HiFi" even existed.
That was my point, If the only goal and the definition of a great amp, were there literally and ability to deliver the correct sound. No one would ever boy a tube amplifier:)

But, don't be discouraged. Many people come to this hobby with some pretty strange expectations of what can and can't be done... or what should or should not be done. If they are sufficiently interested they will spend the time and make the effort to learn and the ones who do are most often very glad they did. These are the people who stay with it and develop the very projects you are looking to try.
Hmm maybe I do have strange ideas, but I do think that if you asked some of the best, to design an amplifier, and then publish the project, so people could order board and assamble them self. You would get a lot of great results out there. I have no hope of making an amplifier that sounds better then a car-crash. If I have to start from scratch, but if i get a great pre designed project in my hand, do I think I can end up with something, better then a clock radio:)





Also take in consideration how much power you really need, if you're speakers are high efficient I would go for low power ab or pure a , a jlh for example.
All amplifiers are made by compromise, low power, low distortion.
Am building greg ball ska150 now, and I really feel it's a amp I'm gonna love.
Yes, I have sometimes wondered why some are going after the wattage number, "I have 1500W"... "pfft I have 2500W". I think that headroom is fare more important, so a 50W or 100W with lots of headroom is the ting to go for.


I would spend lots of time reading and researching, mostly on this site to begin to discover the ins and outs of this great hobby.
You’ll find that it’s only a re-creation of a musical performance, is not ALL about accuracy, but balancing harmonics as well. Another thing to consider is that there are many different backgrounds, and viewpoints that make it all work here on this site.

The chip amps are a great way to start for sure, as can be DACs, headphone amps, but definitely research before buying, as many diy kits and assembled boards have their, uh, trade offs(tragic errors).
As for power, it can depend on other things like expectations, size of room, speakers, but overall, for me, around 100 watts is plenty. Less can be just as rewarding however, and much easier to start small to appreciate the effects of a power supply, etc.

A decent multi-meter, a low amperage soldering iron, and did I mention research?
My thought also, instead of just randomly selecting any kit, I'd decided to ask you guys, I know that some of you have created amazing things, only a commercial can dream about:)
I do normally put people in 1 or more of these 4 categories:
1) Music user, don't care what are making noise, they just want something while vacuuming.
2) Gear lover, it's the hunt for the best gear, the joy by finding gear that blow you away.
3) The analyze lover, here is it all about clean sound, details, deeeeep bass and being able to hear a fly 50 miles away.
4) Music lover, here is it all about the music, the nodding, air guitar and air drummer. It does not matter so much if the sound is a bit off or noddy, just as long you get a smile on your face.


I am maybe thinking of getting an old used amplifier and then maybe add some voltage, ampere and capacitors, just to give it more punch and power to force the speaker to cooperate:)
 
I do normally put people in 1 or more of these 4 categories:
1) Music user, don't care what are making noise, they just want something while vacuuming.
2) Gear lover, it's the hunt for the best gear, the joy by finding gear that blow you away.
3) The analyze lover, here is it all about clean sound, details, deeeeep bass and being able to hear a fly 50 miles away.
4) Music lover, here is it all about the music, the nodding, air guitar and air drummer. It does not matter so much if the sound is a bit off or noddy, just as long you get a smile on your face.
I'm type 5. Music lover, owns & plays a great piano, wants my hifi to sound like that on pieces I don't have time to learn to play. Piano is about the hardest instrument to do right, and a great test for speakers if you are out shopping. If it will do that, the other instruments will be accurate also, IMHO. That's how I ended up with SP2 speakers, best sound I've ever heard in this flyover state. Piano has a high crest factor when the hammer hits, and solo top octave tracks are a great high freq. intermodulation test: no sibulance allowed. Plus tinkly bells & percussions instruments stress top end. check the bass too, low A note piano is 27 hz.
Per your watts comment, I listen on average base level 1/8 watt/channel on 101 db 1w1m speakers. When the cannon goes off in 1812 overture, that is 72 db up on a CD. Takes 40-50 watts to do that. My AX6 board does 70 w for 5 seconds at a time. It will not do that for much longer, the single pair transistors would violate soa limit and short. Secret, 70 v rail for average 1 Vpp out into 8 ohms, so it can peak at 28 v (average) when called for. Occasionally.
If you're listening to low crest factor music, like singer-songwriter acoustic guitar, or by contrast compressed hard rock that's the same volume all the time, you don't need that dynamic range. LM1875 @ 25 W is fine for that. (suggested previously).
The PV-4c with 2 output pairs/channel is rated 140 w/ch, I don't need that much, but it works more reliably than my AX6 built point to point which is humming right now. (after 5000 trouble free hours, 14 hours a day 3 years).
Look around, there was a parasound in town for $400 on craiglist, probably buggy but that's why we diy.
BTW trouble with PASS ACA as shown previously, is the LSK489. Digikey, farnell, mouser never heard of them, didn't check reichelt as I can't read German. Watch lateral fet amps too, available in Europe but NOT HERE! Without passing through customs where majic fingers lifted some TI CMOS IC of all things last year. (farnell made good after 3+ week delay).
 
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