2x250 IRS2092 amp build

[[email protected]]

Re: 2x250 IRS2092 amp build

Hong,
Yes technically if you are looking from +V to -V there are two caps wired in series. But every thing in the electronics world is almost always referenced to common (or ground). In that case there is only one cap (it is actually two 20,000uF in parallel) from the +V rail to ground and one cap from the -V rail to ground.

From +v to ground and ground to v-. They are polarized so should the cap on the v- be turned around?


In my case, with dual rectifiers, should the ground be omitted and the caps be wired individually?

[Wolf]

Re: 2x250 IRS2092 amp build

From +v to ground and ground to v-. They are polarized so should the cap on the v- be turned around?

No- don't flip it around.
Later,
Wolf

[[email protected]]

Re: 2x250 IRS2092 amp build

My psu is exactly like the top one here. GD does not go to the amp, only to ground like the top pic.

http://techtalk.parts-express.com/attachment.php?attachmentid=46993&d=1400451374

[neildavis]

Re: 2x250 IRS2092 amp build

My psu is exactly like the top one here. GD does not go to the amp, only to ground like the top pic.
http://techtalk.parts-express.com/at...3&d=1400451374

Here's maybe an easier way to see the problem with the original configuration: If you connect a preamp or some other device that has a chassis ground connected to its signal ground (which is often the case), then the "Gnd" at the IRS2092 ("G" in the lower drawing and signal ground for the preamp) will be connected to GD through "earth". That doesn't cause any sparks or high current, because those caps don't have any voltage on them anyway. However, it becomes obvious that the caps "in the middle" aren't contributing to the power supply filtering.

So you want to get rid of that GD connection. If you just remove it, your caps would be in series, as others have pointed out. So you need to do some rewiring to get all of those caps in parallel. What you have now will actually work, but you are only using half of the capacitors to filter the heavy supply current and the chassis isn't properly connected to signal ground.

I only posted because it looked like there was still some confusion as to why the original configuration wasn't correct. Hong has the right circuit now. In this case, simpler is better

[[email protected]]

Re: 2x250 IRS2092 amp build

Thanks so much for being patient with me. I will make the changes.

[neildavis]

Re: 2x250 IRS2092 amp build

Thanks so much for being patient with me.

You did a good job on the chassis. I'm glad to see more people getting involved in amp-building.

The grounding is always the most mysterious part of amp-building, especially when you make your own boards. Many years ago I built a six-channel amp that oscillated and fried the outputs whenever I turned it on. By the time I separated out all of the grounds and got the amp stable, I was no longer interested in working on it. Also, I had used power-hungry TTL logic for front panel touch switches and needed to redesign too much to use those new CMOS devices, so I moved on...

I've always been afraid of electricity--I always dread that first flick of the switch. Too many exploding parts over the years :eek:. The worst scare was when I was debugging that six-channel amp with an oscilloscope. It used a triac/zero-crossing circuit to turn on and off the power, and it never occurred to me that putting a scope ground probe on the AC line wasn't a good idea. It actually vaporized the scope probe ground wire. I know it takes some nerve and guts to work on amps, so I admire your desire to work on this stuff.

Keep it up and don't get frustrated--it's a fun hobby with good rewards.

[hongrn]

Re: 2x250 IRS2092 amp build

I don't feel too bad now after reading this Neil. I've had exploding caps, major sparks from allowing wires to touch each other, melting resistors, and too-numerous-to-count mishaps trying to understand how to put an amp together. Thanks for the encouragement, the guidance, and taking time to answer our noobish questions.

Hong

You did a good job on the chassis. I'm glad to see more people getting involved in amp-building.

The grounding is always the most mysterious part of amp-building, especially when you make your own boards. Many years ago I built a six-channel amp that oscillated and fried the outputs whenever I turned it on. By the time I separated out all of the grounds and got the amp stable, I was no longer interested in working on it. Also, I had used power-hungry TTL logic for front panel touch switches and needed to redesign too much to use those new CMOS devices, so I moved on...

I've always been afraid of electricity--I always dread that first flick of the switch. Too many exploding parts over the years :eek:. The worst scare was when I was debugging that six-channel amp with an oscilloscope. It used a triac/zero-crossing circuit to turn on and off the power, and it never occurred to me that putting a scope ground probe on the AC line wasn't a good idea. It actually vaporized the scope probe ground wire. I know it takes some nerve and guts to work on amps, so I admire your desire to work on this stuff.

Keep it up and don't get frustrated--it's a fun hobby with good rewards.

[PWR RYD]

Re: 2x250 IRS2092 amp build

I'm not sure if that is encouragement or discouragement :eek:

[hongrn]

Re: 2x250 IRS2092 amp build

Craig, you wouldn't qualify to work on the suicide hotline for sure.

I'm not sure if that is encouragement or discouragement :eek:

[[email protected]]

Re: 2x250 IRS2092 amp build

made the changes and no magic smoke! Thanks to all!

[robertcottiers]

Re: 2x250 IRS2092 amp build

I'll bet the fingers were trembling a little bit before you hit the Power Switch.....That would be normal.:D


Bob

[howard]

Re: 2x250 IRS2092 amp build

Can you tell any difference?

[[email protected]]

Re: 2x250 IRS2092 amp build

NO Robert. I just knew that it would be fine. Hong said he would go on a gameshow and win me a new car if it didn't work perfectly!
I won't really know if it is a huge improvement until I get it in the home theater. In my small room, its great.

[[email protected]]

Re: 2x250 IRS2092 amp build

oops

[hongrn]

Re: 2x250 IRS2092 amp build

Hong also promised to install a stainless steel pole in Lowell's living room, and give him a one-year free supply of strippers if the PSU didn't work. Anyone else wants this deal?

NO Robert. I just knew that it would be fine. Hong said he would go on a gameshow and win me a new car if it didn't work perfectly!
I won't really know if it is a huge improvement until I get it in the home theater. In my small room, its great.