Who has built their own?

Status
Not open for further replies.
Jump to Latest
#21
Hi Mike!
Yes, it is an art.

I did my first steps when I was about 16 years old
and still in school and I thought that this would be a good oportunity to save money 😉
.... needless to say, that nothing was working in the beginning.
It took me 2 years and all my money (and several inconviniences in school :angel: ) to learn the basics. Especially to
learn about oscillations....!!!
But it's more than a hobby. It's passion.
....a forgotten passion until I found this forum....

Good luck
Markus
 
#24
Chris!

I think very well! The biggest one is 2 kW. To be honest the distortion at high frequency is definitely high, it can be clearly seen on oscilloscope, but I didn't hear any problem when I tryed it. Maybe because harmonics are over 20 kHz (tipically 40kHz). It is undestroyable by output short circuit, switches off above 60-90A(depends on tr. chip temperature), and bridged topology avoids supply pumping. On testing with music, temperature exceed 40 C only when I turned off the fan.

S/N is over 110 dB at mono operation, and about 80 dB if I use 2 of them side by side.

I would work on lower distortion, but somebody has taken off its power supply! 😱

The other one has better quality, but lower power. It can be synchronised, this way stereo operation is not problem. (There are 2 version of this on the page.)
 
#25
ChocoHolic said:
Hi Mike!
Yes, it is an art.

I did my first steps when I was about 16 years old
and still in school and I thought that this would be a good oportunity to save money 😉
.... needless to say, that nothing was working in the beginning.
It took me 2 years and all my money (and several inconviniences in school :angel: ) to learn the basics. Especially to
learn about oscillations....!!!
But it's more than a hobby. It's passion.
....a forgotten passion until I found this forum....

Good luck
Markus
Click to expand...

Oh yeah, i started with some amps at the same age, but with very
moderate success. A year ago i started again, now with much more
success. Somehow its curiosity what keeps me working on these.
And yes, "Passion" was the word i was looking for...

I still have to learn much, sometimes amps seems to be like voodoo
to me, changing minor things can completely change the sounding
of the amp. This must be mystical art... 😉

Michael
 
#26
"distortion at high frequency is definitely high, it can be clearly seen on oscilloscope, but I didn't hear any problem when I tryed it. Maybe because harmonics are over 20 kHz (tipically 40kHz)."


That particular light went on in my head not too long ago - namely even at 10kHz harmonic distortion is almost irrelavant. The exception is if it is a surrogate for IM. I have seen bandwidth limited THD plots - very interesting since calculated that way, peak THD starts falling after 5kHz depending on the bandwidth choosen. This may more a more useful indication of audible sound quality than the conventional plot. It might me a good idea though to distinguish between THD and THD+N.
 
#28
demons_wing said:
pafi..would you have a switchmode power supply design of your own that you would share?...what i am asking for is calculations for the components...maybe its too much to ask lol?:bawling:
Click to expand...


Ohoh, DIY on a switchmodepowersupply ?
Some diyAudio-moderator might hurt you bad, as you are talking
about lineoperated stuff here... 🤐
Just think about some 1000uf-cap loaded with 360v, ouch ! :bigeyes:
I once had a 220uf-cap loaded with this voltage, und accidently
shorted it. The cables were about 2cm shorter, and i had loud
beeping in my ears for hours. Imagine what happens to a BJT
getting this much energy after breaking.... :bomb:

Michael
 
#30
hahhaa..i see your point mike..i used to be a PSU tech back in the day...have been electricuted many a times...my first was from a 500W PSU with PFC...420V across the boost caps..lol...not fun..i have always wanted to get into switching design..that why i asked..
 
#32
This also deserves some respect when charged, I use it for SMPS prototyping. It measures 65x105mm and weights about 1Kg

An externally hosted image should be here but it was not working when we last tested it.


Pretty obvious disclaimer : This is strongly NOT recommended for unexperienced people, some risks include : Lethal shocks, fire and the capacitor exploding on your face...
 
#33
demons_wing!

Sorry I can't show you calculations. I allmost never put it down, and there are parts whom value cannot be determined exactly. Calculations of main parts are on the net many places, for example: http://henry.fbe.fh-darmstadt.de/smps_e/smps_e.asp

You will also need some creativity and experience for designing PSU.

EVA!

What about these?

http://www.hszk.bme.hu/~sp215/elektro/3300_uF_350V.jpg
http://www.hszk.bme.hu/~sp215/elektro/330_uF_320 V.jpg
http://www.hszk.bme.hu/~sp215/elektro/345A_1000V_tirisztor.jpg

One of these is a piece of cake, but in supply of telephone centrals there are many dosens in parallel.

Earlyer I had a 10uF 6000V capacitor. I didn't dare to discharge. 🙂

Everybody!

I think one shouldn't be affraid of 230V, but learn about it! It is only Low Voltage! With a little care it is perfectly safe. (IMHO!) (Except if there is storm out there.)
 
#34
Oh, the problem when talking about risky practices is the stupid justice system of U.S.A. and other countries

In these countries, if somebody hurts herself building a project whose schematics are on that forum or doing something proposed here, then he can start a lawsuit against the forum and has lots of chances to win it and put the webmaster in serious trouble

Stupid, isn't it?. In other countries these things are just not possible [ie: In Spain everybody would laugh at you if you try to start such a lawsuit]

In these circumstances it's better to put disclaimers everywhere

Some examples of stupid laws, lawyers and judges that operate in U.S.A. :

Main page of Stella Awards : http://www.stellaawards.com/
2003 Award winners : http://www.stellaawards.com/2003.html
2002 Award winners : http://www.stellaawards.com/2002.html
 
#36
Hi Eva !

I think these caps are really hard to top:

http://www.alltronics.com/images/20p002.jpg
Rating: 14 uF 20KV 2800 Joule 14" x 8" x 24" --- Mineral oil filled

http://www.alltronics.com/images/23p020.JPG
Rating: Aerovox PX15QD58 7.14uF 50KV approximately 9000 joules.
30" x 11" x 14"

I believe, these caps wouldn't only kill you, they vaporize you !
Have no idea what these are good for...

Another Disclaimer:
Don't even think about playing with these, sudden death WILL result !

Michael
 
#39
Hi all,
Nice caps you found out there. Thats something for a beginners
right of the 20kV power-line electrostatic speaker project.

Seriously, thats probably the target application of theese guys, VAR compensation
for inductive loads etc on powerlines.

/ Mattias
 
#40
If energy is the most important, then Ultracapacitor is the best. But sadly it can't be lethal. 😉
 

Attachments

  • ultraca.gif
    ultraca.gif
    37.1 KB · Views: 155
Status
Not open for further replies.
Top Bottom