Infinity BU-120 with Audiosource Amp-100?

[CorrND]

I just bought a pair of refurb'd Audiosource Amp-100's from ubid yesterday.

http://www.audiosource.net/amp100.html

One is going in our bedroom to run a pair of Polk R15's off our TV (nice cheapie system). I bought a second because it was a good deal and thought it might be useful to have 2 in the future. Now I'm thinking I have a use right now.

I have one of the infamous Infinity BU-120 subs with the crappy amp. I've managed to keep is running over the years by connecting it to the switched output of my amp. I've also tinkered with it a bit and replaced parts as they blew out, but the simple fact is that the amp is a piece of junk. Despite the amp, I've been lead to believe that the driver and housing is actually fairly good. So, I've got couple questions:

1. Is it true that the BU-120 driver is at least half-decent?

2. Would a monobridged Audiosource Amp-100 be a decent amp to drive the sub?

If both are true, I'm thinking about just ripping off the BU-120 amp and replacing it with a plate with some nice binding posts. Any advice would be very much appreciated.

 

[j_garcia]

Normally I would say just replace the sub, but since you already have the spare amp, I say try it out. I'd have to say it will probably work, but not being a sub amp, it may not give the best results. Try it and let us know.

One thing to note - you should NEVER plug a sub or amp into the outlet on the receiver!!!!

 

[CorrND]

Normally I would say just replace the sub, but since you already have the spare amp, I say try it out. I'd have to say it will probably work, but not being a sub amp, it may not give the best results. Try it and let us know.

One thing to note - you should NEVER plug a sub or amp into the outlet on the receiver!!!!

I'll try it out and see how things go. At the very least, it should get rid of the damn background hum!

What's the reasoning for not plugging a sub into the receiver switched outlet? Back when the BU-120s first started dying, many people were reporting that they died with an extremely loud and annoying machine gun sound, sometimes when no one was around. By plugging it into the switched outlet, the theory was that at least the sub wouldn't die when the receiver was turned off. Some (including me) have also been able to extend the useful life of the sub amp in this way.

I suppose the reasoning is insufficient power available on the switched outlet (with resulting overheating, etc.)?

 

[Jack Hammer]

I just bought a pair of refurb'd Audiosource Amp-100's from ubid yesterday.

Not bad for $50 each! I picked up two myself for $49 each. I really didn't expect to get them at that price, but threw the bid in just in case. One's going to a friend who's been thinking about using his zone two, I'll set it up and see if he likes it, if not, I'll find a use for it. I also figured I'd keep the second for future use. I can always sell them for what I paid.

As for the sub in the switched outlet, I'm not fully clear on the reasoning behind it, but I've always heard it was a big No-No.

Jack

 

[CorrND]

So, the experiment was a failure. Either the amp is grossly underpowered or it simply does an awful job in the subwoofer frequency range. Even when I bumped up the subwoofer output on my receiver AND put the volume on the AMP-100 almost to max, the BU-120 was still barely noticeable in my system.

The AMP-100 documentation claims that it puts out 134W in bridged mode, so that should be more than sufficient.

I can't find the review now, but I believe I read someone reviewing this unit that stated decent repoduction in the mid to upper range and weak reproduction in the bass range. Trying to reproduce ONLY sub frequencies probably just brought major attention to this shortcoming.

On the bright side, I'm quite pleased with the AMP-100 / Polk R15 combo. As Jack Hammer said, they're a great deal at $50/each. I got the Polks on a $40/pair sale at Fry's, so for only $90 total, I certainly can't complain about this setup!

 

[j_garcia]

Yes, the problem with plugging the sub into the receiver's outlet is they are meant for low power draw items, of which most subs are not. I tried my Amp One with my sub, which should have been about 150w bridged. It definitely did not do the trick either, which is why I said it may not give good results. My sub is a bit of a beast though...