Destroy It Yourself Pre and Power Amps

Levi_501

Levi_501

Its in The Jeans...
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Speakers are quite common to build. However, is it possible to build pre amps and power amps, successfully ? and power supplys if we can go that far.

How do you know what sort of sound you will be getting ?

Any comments on either transistor or valve would be greatly received.

Thanx
 
Yes, it's possible. Just as I am designing a DAC at the moment, doing a pre is very "easy" (in circuit terms... in terms of actually getting a good implementation it's much harder!), and power amps can range from the extremely simple to the fearsomely complex.

Power supplies are also relatively easy to build as the de rigeur hifi power supply is the hefty unregulated linear supply, which consists of a transformer, rectifier and a whole load of capacitors.

How do you know what sort of sound... well, to some extent that will be dictated by the choice of components (valves? TDA1541 dac? Resistor ladder volume? Black Gate caps?) and the implementation (class A? Class AB? Class D?). Beyond that, layout and specifics in the implementation will have an effect which you can't really judge beforehand unless you're really, really good (not me).
 
IMO speakers are the hardest thing to DIY properly. I'm not talking about things like Julians IPLs as that's a case of assembling a kit that has been well researched and designed but I reckon anyone thinking they can just bolt a couple of drivers and a xover into a box will end up with terrible results. Electronics OTOH are generally pretty straightforward and it's pretty easy to get very good results.

Michael.
 
Not THAT straightforward michael... it's easy to take a design out of a book or datasheet... originating new designs is rather harder. For example, the part of a speaker that really tends to floor diy designers is the crossover as the mathematics behind it are complex, especially when it comes to trying to take into account box resonances and so on.
 
That's what I meant (in relation to electronics). I just think that the maths and physics involved in a good speaker design (not to mention the tools for measuring the results) are way beyond even very competent DIYers.

Michael.
 
Ok then, for a novice at building amps;

Ideally I would like to make up a pre amp, with phono stage and then 4 monoblocks, might be over kill, but hey you can never have to much power ! Power supplys as I need them, is remote pushing the boat to much !

It seems that valve amps are more common to make, but I might be wrong.

I looked at the www.affordablevalvecompany.co.uk however they only sell made up.

I know of Stoekit and World Audio but that is about it. Are then any others ?

Any thoughts where I might be able to go ?

I have never built anything like this, however I did study about some geezer called Ohm, Watt and some other old chaps that had massives beards ! prob should have stayed awake !

Despite of this I am confident with a soldering iron, strippers (oh definately) and machining parts and so on.

Isaac – making a DAC ! blimey that can not be an over night job !

Thanx
 
Heh... it's not as complex as it might seem. Would go quicker if I spent less time on here and actually did it :p
 
If I was you I wold maybe make a Gainclone (just google for it or go to www.diyaudio.com and then chip amps). Dead easy to make and sound pretty good. If you want make one with an input buffer, input witch and volume control and hey presto one very good amp for less than £100.
 
LiloLee said:
If I was you I wold maybe make a Gainclone (just google for it or go to www.diyaudio.com and then chip amps). Dead easy to make and sound pretty good. If you want make one with an input buffer, input witch and volume control and hey presto one very good amp for less than £100.
Click to expand...

Thinking about doing one myself :-

http://www.chipamp.com/
 
I had a chat with a mate who I went to Uni with, he paid more attention to the bearded bloke at the front !

He was said making amps and so on is very easy. All I had to do was get hold of an amp I liked, take the lid off copy the circuit, make one identical and Hey presto !

Is it possible to buy wiring diagrams of manufactured equipment ?
 
There are less savings to be made building your own electronics than there are in speakers. If you buy an amp kit form, you may save 1/3 of the retail cost [or nothing].

Designing a high power power amp from scratch requires a good workshop with scope, sig gen, vaiable psu etc. A TV repair shop 30 years ago would be a good setting. Isaac would probably rightly say you need spice circuit emulator on a PC, otherwise you are basically guessing as you do it, although there are plenty of 'worked examples' out there.
With speakers, it's more a case of using parts that manufacturers would not economically use [ie very good ones], or building speakers that are not UK available - like medium cost, large 3 way designs - not suprisingly when you see most UK houses.

When I eventually find a part time job I like, I will have time to

finish my [in use anyway] DIY speakers

build an attenuator/mono combiner/DI box for various bits like my bass processor [so I only need to handle the bass from the processor, not full range]

build the mother of all pre-amps: RF friendly, with loads of ins-n-outs, various knobs n whistles, M-S processing, etc.

Then I will just run whichever commercial power amp suits.

If any of this is of interest whn it happens, I will gladly share details ala Julian
 
Levi_501 said:
I had a chat with a mate who I went to Uni with, he paid more attention to the bearded bloke at the front !

He was said making amps and so on is very easy. All I had to do was get hold of an amp I liked, take the lid off copy the circuit, make one identical and Hey presto !

Is it possible to buy wiring diagrams of manufactured equipment ?
Click to expand...

Sounds great! bung this guy a tenna and let him get on with it. I'll have a pair of those big Mark Levinsons if he's not too busy..
 
Levi_501 said:
He was said making amps and so on is very easy. All I had to do was get hold of an amp I liked, take the lid off copy the circuit, make one identical and Hey presto !
Click to expand...

Hmmm ....... not too sure about this, what about multi layer PCB boards.
 
Levi - it's not quite that simple. You can have two amps that are schematically the same and use the same components in the same places. One hums and generally sounds pretty poor, the other may sound very good.

Layout is a very significant factor in an amplifier.
 

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