Meet my DIY Amp ... The Exploder

[Kannan_madhu]

After Twelve years the DIY bug bit me again ,recently I assembled an IR receiver for my HTPC which once again got my interest back to DIY . So i decided to do a second project a LM 1875 based amplifier . i got this reference design Lm 1875 datasheet collected all the components and started with a strip board . Today morning i finished soldering the miniature beer cans and parippuvadas to the board and finished the power supply also . I connected my sony ericson to the input and played "Welcome to the Jungle" and I anxiously pressed the power button to the amp hoping it to work and not to have the hum ... i was surprised there was No Hum... NO Crackle .. No Noise ... only problem was there was no Song also . Non of my DIY projects worked in the first go , so i reconnected the wires removed varnish from transformer lead outs, checked the mains etc.. and once again switched it on ... and the speakers welcomed me to the Jungle . i was thrilled like every time a Diy becomes a success. The sound was good but in a moment the volume got reduced and ... KABOOOOM. "Welcome to jungle" turned to "Smoke on the strip board and fire in the capacitor" .....

 

[Kannan_madhu]

 

[Thad E Ginathom]

I always admire electronic DIY, because I can't do it!

Your writing (and building) style is great: grinning at failure, and laughing in the face of disaster. I'm sure it will work [out] in the end, and I'm looking forward to reading the following chapters. For your sake, though, I hope the story is not too exiting.

By the way, aren't exploding capacitors quite dangerous? Or is that only the big ones?

 

[Kannan_madhu]

Thanks for the encouragement Thad E Ginathom
Its a small capacitor a 22uf one which went bust and i was away from the board so nothing dangerous happened , I don't have a spare one right now, so tomorrow i will get one and will be back with "Adventures of Exploder" hopefully with out another Bang . And if it becomes a sucess you can expect more exiting amps like "The Fuse Blower a LM 3886 design" and "The Mains Tripper " sub amp with LM 4875

 

[captrajesh]

I can see the Beer cans but where is the parappuvada?

 

[ukjeyaraj]

Best of luck on your DIY project.

 

[Kannan_madhu]

Captain ,
Paripu vada was there but i replaced it with a coffee bite (polyprop cap) as per audio docs suggestion .

 

[Audiodoc]

This is catastrophic capacitor failure. I had one once and that one was a large 4700 MFD. It was so loud that my parents thought that there was a cracker explosion. It should always be kept in mind that the capacitor voltage ratings be almost double the operating voltage. So if the supply DC voltage is say 25V the capacitor voltage should be 50V or above.

 

[Thad E Ginathom]

...you can expect more exiting amps like "The Fuse Blower a LM 3886 design" and "The Mains Tripper " sub amp with LM 4875

The Substation Destroyer Monobloc power amp? That should blow people's ears off!

Keep up the good work. And the sense of humour

 

[Gijo George]

Had a good laugh just reading your signature:clapping:

 

[ssf]

And if it becomes a sucess you can expect more exiting amps like "The Fuse Blower a LM 3886 design" and "The Mains Tripper " sub amp with LM 4875

:lol:

All the best to your DIY efforts. Keep us updated.

 

[josephjohnt]

Nice effort Kannan. Way to go.

Hope the replacement cap doesn't end in fumes.

 

[jls001]

Thanks for the encouragement Thad E Ginathom
Its a small capacitor a 22uf one which went bust and i was away from the board so nothing dangerous happened , I don't have a spare one right now, so tomorrow i will get one and will be back with "Adventures of Exploder" hopefully with out another Bang . And if it becomes a sucess you can expect more exiting amps like "The Fuse Blower a LM 3886 design" and "The Mains Tripper " sub amp with LM 4875

Great DIY.

Is the blown cap due to reversal of polarity, or due to using a cap with less than adequate voltage rating?

Asking because I've had the "honour" of a blown cap due to wrong polarity:lol:

And it was loud, and it hit the ceiling with great gusto. I was lucky not to be in its projectory.

 

[GeorgeO]

I've heard of the Xplod series, first time I heard of the exploder! Good luck..

 

[Kannan_madhu]

Thanks all for the encouragement, i think its the reversal of polarity may have caused the explosion . I couldn't buy the capacitor today i have a 100Uf one with me, thinking of an experiment with that .

 

[josephjohnt]

Thanks all for the encouragement, i think its the reversal of polarity may have caused the explosion . I couldn't buy the capacitor today i have a 100Uf one with me, thinking of an experiment with that .

Now you are becoming brave for more experiments with all our encouragement hyeah:

 

[Kannan_madhu]

Exploder breaths again ...

I did the critical organ replacement of Exploder today , wired it up and took a AC extension cord and placed the amp in a different room .. plugged it in closed my ears with one hand and a shoulder . And like firing a "Thrissur pooram Gundu" i switched it on ....... no explosions ... i peeked through the door .. no smoke also .. switched it off and connected to my Sony Ericsson, played Karukara Karmukil of avial, powered it again and the speakers served me Avial ... finally it worked . Sound is clean, no humming but volume is low do this need a pre amp ? . I will try with a different source .





For those who haven't heard Karukara Kaarmukil
Karukara by Avial - YouTube

 

[Kannan_madhu]

 

[gopib]

Slowly you are getting there. You may soon have to change your signature
from "thallipoli" to "adipoli":clapping: . I will let you explain the terms for the benefit of
others.

That said, your volume levels is subjective. IMHO it should be sufficient. Check
everything once more....

 

[spy king]

Hey!

Neat Amp, really like your writing style!

Got a few noob questions,

1. Is the chip easily available here?
2. What is the input voltage for the chip? I have been reading about 18V, Will 12V work? I have a SMPS that puts out 3,5,7,12 and 17V, so wondering if I can do away with the transformer section?

Thanks!