What do you think of my home built stereo amp from the 80's?

[mp3streetparty]

I would of bought the 2 ETI 480's 100 Watt version about 30 years ago.

I had the amps in the back of a Philips Radio Gram for many years but only with one transformer a 24-0-24V instead of a 33-0-33V so the output power was down, I had connected a Musicolor 3 to the coloured lights in the Phillips box also.

In the mid 90's I rebuilt the amps into a scrap desktop PC case.
When I was rebuilding it I came across a dead 600 VA UPS, I used the transformer out of it to boost my 24-0-24 V transformer by about 10.5 volts AC so 34.5 V AC on the secondary, a little bit higher than recommended but I have 3 fans in the case.

Do not try with normal amp may/will self destruct.
Another trick is to connect 2 transorb diodes from the output to the rails and drive an ignition coil to the tune of AC/DC and have T.N.T with sparks FX.....

I have only had 2 faults since I built the kits in the 80's.
A few years ago the bias pot went open, I ended up soldering a fixed resistor across it.
One channel has a slight low frequency oscillation in it now so I guess its time to recap the amps after 30 years.

Here are some Pics of a amp that has some reused materials to build it.

Mod for driving ignition coil with AC/DC

Added more supply Caps as time went on now has 3 sets about 7000 uf

Low voltage power supply section, most of the wires came from a cars wiring harness and whatever I could find lying around.

Reused 35 A bridge rectifiers out of something I found and scraped.

Has 3 Transformers 2 connected in series to drive the amps and the other one for the 3 Fans.

I looks like a PC...

Rear panel

Speaker outputs

 

[Adam]

Hats off for building an amp out of spare parts that you had around. A suggestion - you could always clean up how the wires come out the back so that the jacks are mounted against the back of the case.

Have you used it? If so, what do you think?

 

[KEW]

... you could always clean up how the wires come out the back so that the jacks are mounted against the back of the case.

I dunno, I like it as is.
It has a certain grunge/post-apocalypse aesthetic to it!


Whats up with the wood screw siliconed to the side of the fan and the other one tie-wrapped with the wires?

 

[Adam]

I dunno, I like it as is.
It has a certain grunge/post-apocalypse aesthetic to it!

I hear ya. "Two amps enter, one amp leaves."

Whats up with the wood screw siliconed to the side of the fan and the other one tie-wrapped with the wires?

I saw the one on the side, too, but...well...I just didn't know what to say.

 

[KEW]

Do not try with normal amp may/will self destruct.
Another trick is to connect 2 transorb diodes from the output to the rails and drive an ignition coil to the tune of AC/DC and have T.N.T with sparks FX.....

Did you do this? If so, two words - YouTube video!!!

I had a friend who stretched a condom over a 2.5" speaker, glued a small mirror to the center, shot a laser onto the mirror with another mirror to reflect the resulting light patterns to the ceiling. Made a pretty nice light show!
He probably had $200+ in it via Edmund Scientific back around 1980, but you could probably do it for $30 today.

 

[mp3streetparty]

Hats off for building an amp out of spare parts that you had around. A suggestion - you could always clean up how the wires come out the back so that the jacks are mounted against the back of the case.

Have you used it? If so, what do you think?

I could clean up the wires but there is not much room left on the back panel though. I had it in a 19 inch rack cabnet see pic so the wire did not matter.

I used it a lot to drive half of these subs, some movies they rattle the window, I had to put silicon on the backing wood of the wall unit to stop it colouring the sound.

 

[mp3streetparty]

I dunno, I like it as is.
It has a certain grunge/post-apocalypse aesthetic to it!


Whats up with the wood screw siliconed to the side of the fan and the other one tie-wrapped with the wires?

The wood screw was used because on the other side of the heat sink the amps are mounted so there was no room. The cable tie on the screw is for strain releaf of the cables.

 

[mp3streetparty]

Did you do this? If so, two words - YouTube video!!!

I had a friend who stretched a condom over a 2.5" speaker, glued a small mirror to the center, shot a laser onto the mirror with another mirror to reflect the resulting light patterns to the ceiling. Made a pretty nice light show!
He probably had $200+ in it via Edmund Scientific back around 1980, but you could probably do it for $30 today.

Cool.
I need to recap the amp and find a old 12 volt coil not a 6 volt one.
I will let you guys know when have video.

 

[mp3streetparty]

I found the Tone control box today

This bass and treble control circuit was from and Electronics Australia Mag.
I had a dig around for some parts and went and bought the rest.
I used an old PCB from where I used to work and built it in 3d or if there was not enough room I went vertical with the components.

I put it into a AT power supply case it the mid 90's previous to that it used to hang in the air by the wires connected to the controls.

Not sure if it still works today, Its not very serviceable because you have to disconnect large parts of the circuit to get to some parts and I do not have a circuit for it.

I know its nothing flash but you can paint it any colour you like.

This is inside the box.

 

[monkish54]

I had a friend who stretched a condom over a 2.5" speaker

LMFAO!!! I'm not so sure that was the application they were designed for...

 

[Nestor]

I dunno, I like it as is.
It has a certain grunge/post-apocalypse aesthetic to it!


Whats up with the wood screw siliconed to the side of the fan and the other one tie-wrapped with the wires?

Latest tweak from AudiogoN?

 

[ImcLoud]

now this guy loves music