Transistor equivalent

[spec]

I meant I didn't get any chances to learn electronics in school (because there's no electronics education in our school syllabus) and in college (electronics colleges are very limited and I was not able for that, that time). I studied linguistics education instead, even I had no interest on it.

I see- the opposite to me. I had plenty of oppertunities, but too many distractions. The other thing is that many of my mates left school at 16 and got jobs paying big money, for those days, while some of us continued education for another 5 years on peanuts. They had cars, motor bikes latest clothes etc and we were poor.

It is very important to get a good all round education, incuding laguage and maths. Then chose a specialist subject say: electronics, physics, chemistry etc.

I was far too focused on technical subjects at the expense of language etc. To do well you need wide knowledge.

Sometime I feel would be VERY happy with electronics career.

Good choice- many jobs in electronics, well paid too

But do you want to go to work to earn big money or enjoy yourself. If you wan't money become a doctor, dentist lawyer, futures dealer... You can still do electronics as a hobby.

I don't like to discourage you, quite the reverse, but unless you are a junior engineer, you will not be doing design work. Instead it will be managing people, attending meetings, writing reports and so on. When you go up the ladder again you might not even see a peice of electronic equipment.

I am not from so rich family (a son of a farmer). So I never got any chance to feel rocking lifestyle, motor-biking, girlfriends etc.

Rich family/poor family makes no difference as long as you have a good family, good health and good brain. As long as you can get the essentials of life that is all that is necessary. When I first got married I was poor. If the TV went wrong or the cooker went wrong or the boiler it was a big issue. But gradulaly things got better. Now if the cooker goes wrong I would phone the local store and ask them to replace it without further thought. I bet you have some nice countryside to enjoy.

 

[spec]

I learned a little about electricity in school but nothing about electronics. I learned a fair amount about electronics from magazines...

Same here- my dad was a big influence too- he was an electronics hobbiest

...I am also still learning...

again me too- learnt/revised a lot on ETO

I always like hearing music but I did not like the distortion in rock music, maybe the performers were deaf to the horrible high frequency noise of FUZZ.

Know what you mean. I prefer the Fender/Vox amp sound, but unlike you also like the distortion of a Marshall amp. What I don't like is the overmodulation and compression on some rock recordings. Makes it sound dull and lifeless compared to live rock

I never had a motor bike

I only had one motorbike and had numerous incidents but others had motorbikes. I made a copper silencer for one of my mates- did it sound good. You could hear it from miles away. I did a bit of tuning too- port reprofiling and raise compression ratio mainly. But I always read about motorbikes- have many emags on laptop.

I am still attracted by a pretty girl.

It's part of male ROM

 

[audioguru]

Maybe I am a Professional Dirty Old Man.

 

[spec]

Maybe I am a Professional Dirty Old Man.

Just a normal healthy male.

 

[Nikolai Petrenko]

Huhuhu, I fail exam . But have you finish the circuit yet? spec?

 

[spec]

Huhuhu, I fail exam . But have you finish the circuit yet? spec?

Sorry to hear you failed your exam- what subject?

Can you clarify- which circuit do you mean?

 

[Nikolai Petrenko]

Sorry to hear you failed your exam- what subject?

Can you clarify- which circuit do you mean?

Physics, I was fool,(but the exam not easy)

I mean 20W amp circuit and (need preamp circuit?)

 

[spec]

Hmm, Physics never easy.

About the power amp

(1) 8 Ohm speakers?

(2) single supply rail or dual supply rail?

About pre amp

(1) What input?

(2) What controls?

(3) Opamp or descrete transistor construction?

 

[spec]

ERRATA

 

[spec]

 

[spec]

 

[Nikolai Petrenko]

Thanks you, I think preamp use NE5532 is better than TL072, but I still like discrete transistors ones,

 

[spec]

Hi Nikolai,

The NE5534, is not available from your supplier. Thats why I used the TL072. The TL072 is designed for hifi and sounds ok. It is slightly smooth and pleasent sounding. With the basic circuit, if you fit an IC socket (turn pin) you can then try, more or less, any opamp, including discrete, like the Buriston amp. I would suggest that one of the audiophile opamps would be bar far the best- they sound superb. I will post a list for you to have a look at. But suggest starting with a TL072 to get the system going.

If the power amp is too complicated for your liking it can be stripped down to the basics. But when you lay out the PCB alow for all the circuitry so you can upgrade later. The only way to test an amp, after the technical side has been sorted and it is running reliably, is to listen to it on your chjosen speakers.

By the way, never connect an amp that hasn't been proven to your speakers. Get a nice big 15 Ohm or so resistor and put that between the amp output and the speaker- I say this from experience!

 

[Nikolai Petrenko]

NE5532 still available, but this amp will need preamp? Or the preamp is necessary? If make preamp, I would like it is a tone control 3-5 bands

 

[spec]

NE5532 still available.

Are you saying that you want to use the NE5532. If so, no problems. Let me know and I will have a look at that.

but this amp will need preamp? Or the preamp is necessary?

The audio power amp can be used without a preamp; it all depends on your signal source.

If make preamp, I would like it is a tone control 3-5 bands

OK , but tone controls equilisers etc, not good for hifi.

 

[audioguru]

Tone controls can adjust the sounds to the way you like them. Maybe the original recording or your speakers has/have too much high frequency boost or cut, midrange boost or cut and/or too much bass boost or cut.
Every radio and TV station sounds different and tone controls can make them sound better. Use 5 bands only if your speakers are really bad.

 

[spec]

Some audiophile opamps:

 

[spec]

Tone controls can adjust the sounds to the way you like them. Maybe the original recording or your speakers has/have too much high frequency boost or cut, midrange boost or cut and/or too much bass boost or cut.
Every radio and TV station sounds different and tone controls can make them sound better. Use 5 bands only if your speakers are really bad.

Agree. It is much better if you need it to have contols for sorting out a poor signal source, but if you are talking hi fi by definition you would not have a poor signal source. Every stage you put in the reproducing chain detracts from the quality. I think that graphics equalisers and such should be separate from the hi fi chain. Most upmarket amps in the UK don't even have tone controls.

It makes no difference to me though and if a gra[phics equalisewr are really needed- no big deal.

 

[KeepItSimpleStupid]

spec
Generally, you don't fuse neutrals. Not sure about rules in Vietnam. You "generally" don't fuse Neutrals, but only one system (in the actual device) I ever worked on fused (had a breaker) one in the US. 3 phase (90 A 208 V) with neutral and ground. Power out was at least 15 kV at 1.5 A. Open for discussion.

OK , but tone controls equilisers etc, not good for hifi.

Well, don't "quite" buy that. I put better speakers on a crummy OEM car amp and heard nothing but hiss. One car, the amp has built in equalization in it. The there are tone controls. I think there's always room to match acoustics.

You have the bass, treble and midrange, the octave equalizers and the parametric equalizers.

 

[spec]

spec
Generally, you don't fuse neutrals. Not sure about rules in Vietnam. You "generally" don't fuse Neutrals, but only one system (in the actual device) I ever worked on fused (had a breaker) one in the US. 3 phase (90 A 208 V) with neutral and ground. Power out was at least 15 kV at 1.5 A. Open for discussion.

Hi Keep, I'm not sure what you are saying about fusing neutrals. The various PSU scematics I have posted only have a fuse in the live line, which is normal practice as far as I know. Are you looking at the double pole switch which disconnects both live and neutral. Perhaps I have used the wrong symbol- it is only supposed to be a double pole double throw mains switch, which is pretty standard.

Well, don't "quite" buy that. I put better speakers on a crummy OEM car amp and heard nothing but hiss. One car, the amp has built in equalization in it. The there are tone controls. I think there's always room to match acoustics.
You have the bass, treble and midrange, the octave equalizers and the parametric equalizers.

Oh sure, I am not saying that graphics qualisers are not useful, far from it. I use them myself for listening to SW radio and testing cheap earbuds, but by definition that is not hi fi- more like very low fi.

With hifi the less you mess with the signal the better. This is a big subjet- much scope for discussion.