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Old 17th August 2008, 11:29 AM   #1
lineup is offline lineup  Sweden
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Wink DIY Power Amplifier designing by Listening Only

01. take one idea for power amplifier AMP
02. build one power supply for AMP
03. build one prototype of AMP
04. attach dummy load
05. power on AMP
06. if no smoke, power off AMP
07. attach your favourite speakers

08. power on AMP
09. play some music
10. listen carefully
11. power off AMP
12. make eventual changes in AMP according to listening result
13. repeat from 08. until satisfied

14. design complete
15. post images & schematic at

This way you need only one multimeter to check out voltages
and eventually one thermometer to check out temperature of heatsinks.

And you need not much more than your ears and good portion of patience.

No simulation software.
No analog or digital oscillopscope.
No datasheets and curves of one million things.
No boring technical discussions and interference from besserwissers that do no good.
No bother about strange & complicated theoretical audio unconfirmed hypothesis.
No worry about any distortion levels, harmonics, bandwidth, damping / feedback factors and other such junk.

Just build, listen, design & enjoy
We should not make diy power amplifier design & construction more difficult than it is.
When it is so very easy & simple, in fact.

Lineup audio regards
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Old 17th August 2008, 02:20 PM   #2
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Default Yep... we cannot avoid some calculations...but very basic ones.

The good judgement is made by the ears that will evaluate latter.

Human ears judge, because human ear plus brain will listen.

This kind of personal adjustment is great... all of us have competence to adjust into try and error substitution of parts..there's no one unable to do that...have only to learn basic calculations and how circuit works and biasing... some formulas of frequencies used to input filter, input capacitor, zobel filter, feedback network and a good knowledge about how miller capacitors works, mirrors, current sinks, bootstrapp and other simple things.

It is a hell easy..... but it is a hell hard.... hard work, to adjust...and we have to build keept basic, and the other one is tweaked... this way you have reference.

Or the reference can be something considered JLH, and to some folks the LM we have to tweak to make the amplifier sound better than those ones into your own evaluation and perception (taste, experience, preferences)

Never evaluate an amplifier without compare with other, we use to fool ourselves...the last one will be the better if you have not compared...the most expensive one will decided as better if you have not compared, the most sophisticated and complicated one will be considered the better one if you do not compare them with a reference.

We judge because brand is famous... we judge because others have must be good... we judge as good because is expensive..we judge as better because has more power, because is more pretty, we judge something you have made as better BECAUSE YOU HAVE MADE..... because you have created, assembled or designed or tweaked...humans are self centered..... so.... have not good qualities to judge...humans have not competence to judge their own things....must be...have to be a A to B blind comparison testing... you cannot know the other amplifier into the competition.... other guy will operate switches sending sound to a single speaker (of course the one result in a better conversation with that speaker will have ...try other speaker too)...... you will never know the one is A and the one is B...... adjust both amplifier to same level of power.... you cannot see them.... dark room...just listening and sitted very confortable... cannot be feeling unconfortable, having pains, hungry, angry, nervous or anything that can disturb your listening..... the one will operate switches will say.... this is A.... now b



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Old 17th August 2008, 06:04 PM   #3
lineup is offline lineup  Sweden
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Smile we have not to calculate if have some other schematic to go from

only if is a totally new design we need do any math or calculation

otherwise we an just setup the standard circuit

then use my described listening test
to tweak and modify until we get most satisfactory sound
note: this may be very different for different ears

Such tweaks as
- power supply diodes: silicon or schottky
- different power supply caps, values uF and Brands, like RIFA, ELNA etc.
- bias in output stage power transistors: e.g. 20 mA, 100 mA, 250 mA
- input caps, values uF, type e.g. electrolyt, polyester, polypropylene, ceramics
( yes, ceramics ... have you tested and listened .. if not, shut up )

you get the thing i am talking about
don't you

ain't nothing new,
good audio people has done this for 100 amnd 100 of years
without any calculating, measuring and hard thinking & figuring out
without all other complicated junk overload that some geeks like to use

ordinary plain and good hobby audio and tweaking
that's it people

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Old 17th August 2008, 08:40 PM   #4
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Default A very good idea... this develops a lot and produces fun

Good idea....but people need to work on burn fingers.... it is very pleasant despite the burns into the finger tips.

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Old 17th August 2008, 10:42 PM   #5
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Location: Smoky Mountains , Tennessee
Yeah. I agree. To with stupid simulations, your ears
are the final judge. I built HT sub amp and know the distortion is
<.1% but woofer outputs 1% maybe 10% at 200 watts but it sounds so good ..

With full range audio I've done some crazy stuff , like change caps with the power on!!

Ceramics don"t sound too bad, Ive used them when I couldn't find mylar or silver mica in junkbox.
the only area in a amp not to use them is miller comp. in VAS
I had a amp become a tone generator once ... Blew caps like
firecrackers .. also at certain frequencies in the
input filter they resonate.With current sources ,ps ,bypass duties
ceramics make no differance.

It is fun and rewarding to round up all the old stereo junk on the streetcorner and build away(good for environment too!)
My present amp is a old fisher stereo 500VA 44-0-44 transformer,
scrapped hammond PS heatsink(huge),2- 12000uf caps from run over sanyo receiver,small driver heatsinks from PC monitors.
I pay finders fee (deposit)5$ for old stereo/pc so I get cheap
parts and get to see how cheaply commercial amps are made..
(no heatsinks on drivers )ha ha..

All these people on the forums who spend 1000$ on parts/cases.
shop on Ebay find old junk hafler or other commercial amp
that is broken,get circuit from Quasi,destroyer ..modify to PS in
junk amp..all done TRUE DIY for 150$ ..wife won't kick your butt for spending grocery money on new toy!

P.S. I read that you need no spec sheet on component.. BUT,you
will most likely stink up house with many burnt parts
and make your hobby expensive. Go download as many tranny
datasheets and schematics as you can possibly pirate(I have
all schematics, now he gives you none.)start with 2SA-D,TIP,MJx,BD, 1N-diode,etc.Get it all , then organize,
get 20-30 thousand of them...all set. IF any here need schema
or datasheet I have 50k and will post private ip(all are PDF,high
quality and sorted.)happy building/listening.
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Old 17th August 2008, 10:53 PM   #6
Dave is offline Dave  New Zealand
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No datasheets and curves of one million things.
Reading the datasheets is probably a good idea.
DIY DAC, 24/192 inputs, fully balanced
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Old 17th August 2008, 11:36 PM   #7
Tim__x is offline Tim__x  Canada
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Location: Edmonton area, Alberta
How are you going to start?
Obviously you can't listen your way to a working amplifier topology, from let's say a single resistor, adding components as they 'sound'.

To have any hope of a functioning amplifier requires, thought, design, and sound numbers based engineering.

Trying to design an amplifier by purely by ear seems analogous to trying to formulate an argument against reason (which, disgustingly, I recently saw in a major scientific periodical), any attempt contradicts the very premise it's based on.
Sorry to intrude on your thread.
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Old 18th August 2008, 07:17 AM   #8
snoopy is offline snoopy  Australia
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Location: Melbourne
And the end result which meets all of the above requirements is ...........

Click the image to open in full size.

Instructions on how to use:-

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
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Old 18th August 2008, 08:14 AM   #9
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good one!!
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Old 18th August 2008, 10:33 AM   #10
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Default Yes... speaker are so bad that you really need a horn to help them

The best ones are 1 percent efficient..... so.... you pump 100 electrical watts and have as a result 1 acoustic watt... and this is the best ones...the superb ones.

When you, dear folks, start to dominate all the theories and measurements, and simulators, and spectrum analisers.... when you reach around 60 years old alike me and Mr. Line up.... both of us building, creating, designing, testing into simulator, measuring, comparing, listening and sharing informations with others you also will perceive that the solution is to listen and to adjust using your ears, even perceiving that as ridiculous today, you will revert to that basic thing after you have experienced the sophistication.

I have 48 years doing...more than 4300 amplifiers made... have worked into service places, not only audio but also Radio and also Video Tape Recordings..... the step by step adjustment were made using spectrum, scopes, distortion measurements and deviation and frequency counters and so on.

It is strange to you... also ridiculous and seems foolish..but i ensure you that after you have obtained really big experience..years will realise that simple thing...ears...human ears is the big tool... the best tool to evaluate audio.


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