IRAUDENSTEIN: A parts bin monster

[theAnonymous1]

I just finished a beast I dub "IRAUDENSTEIN". This is a dual mono BTL amp based around two IRAUDAMP1 boards. I managed to build the entire beast out random parts on hand (yes, even the IRAUDAMP1 boards were tossed in a parts bin). It weighs in at a whopping 44lbs.

I built an input buffer/bridge adapter out of one LM4562 and two OPA1632 to run the amp boards bridged and add some gain. The overall system gain is just a little over 32db and rail voltage is +/-50VDC. There is a small 555 timer circuit that delays the turn on of the amps boards when the mains switch is turned on.

The IRAUDAMP1 boards have a few mods done to them that I won't really go into. The output FETs have been changed to FDP42AN15A0.

Here is a list of parts used in the power supply.....

Transformers: 4x 150W 100V audio transformers used as power transformers.

Capacitance: 160x 820uF 63v panasonic FC (32,800uF per rail).

Rectifiers: Two separate bridges made out of 80A 600V Ultrafast diodes.

I also built a "ground loop breaker" out of the same diodes used for the power supply.

I have no clue how much power this will put out...... all I know is this thing scares the **** out of me . I've been testing it on two 12" 4 ohm car subs in a sealed enclosure. I know a mutli meter and clamp on ammeter isn't the best way to measure power output, but I measured about 74Vrms @ ~17A at the speaker terminals. It didn't sound distorted at all, but I was scared to push it any further.

The great thing is I have absolutely no use for this monstrosity. It will probably just end up in the closet when I'm done playing around with it. I wish I had a garage or basement to use it in.

Here are some pics. The front panel is in the process of being repainted.......

[Baldin]

Looks nice

"ground loop breaker"

What's that??

with +-50V and bridged you should be able to get something near 1000 W I guess .......

[theAnonymous1]

Thanks, this is the most powerfully amp I own and I have absolutely no use for it.

Scroll down to "Figure 3" at the link below to see what a ground loop breaker is......

http://sound.westhost.com/earthing.htm

[gurley123]

Thanks, this is the most powerfull amp I own and I have absolutely no use for it.

Maybe you could learn to arc weld now.

[theAnonymous1]

Originally posted by gurley123


Maybe you could learn to arc weld now.

Heh, that was actually my biggest fear when I first turned it on.

Below is a pic of what I've been powering with this beast for the last day. It might not win any HiFi awards, but man this mess can scream....

[theAnonymous1]

I just did a torture test of a 20hz sine at full volume, both channels driven. The heatsink heated up quite a bit, but nothing blew up (to my surprise).

I measured ~60Vrms @ >9A, which is less than what I measured with music, but that's to be expected. The rail voltage dropped to +/-33V during the testing, but the mains also dropped from 118V to 110V. I wasn't thinking when I wired the primary side of the transformers and only used 18AWG.

Oh well, >500WRMS per channel with a 20hz sine is pretty good I think.

[luka]

OMG, this is overbuilded, I LOVE IT, great looking too

[dudaindc]

I love it too!
It never occurred to me to use 100V audio transformers the way you did - just great!

[theAnonymous1]

Originally posted by dudaindc
It never occurred to me to use 100V audio transformers the way you did - just great!

Yeah, probably not the smartest thing to do, but it seems to work just fine. There isn't any leakage that I could measure and they don't get warm at all.

It probably would have been safer to run two 70V taps in series with the mains, but then the secondary voltage would have been a bit lower than I wanted.

I definitely wouldn't suggest using them in a piece of equipment that you plan to move more than once.... these things are heavy!

[dudaindc]

Originally posted by theAnonymous1
...
Yeah, probably not the smartest thing to do, but it seems to work just fine.
...

Agree, but that is not my point - building something entirely from "whatever you can find in the parts bin" is. Well done!

(I have some of those Altec transformers... )