2-Channel Amps

dr1978

Was telling my buddy about this fiasco and he said he has an AMC 2100 sitting in his closet that he'd give me! Only 100 wpc but it's better than nothing and should allow me to cool my jets and take my time on my next purchase.

Any opinions on AMC?

verb

Some anecdotes on Audioreview:
http://www.audioreview.com/product/amplification/amplifiers/amc/2100.html

dr1978

Sounds like I should be happy enough for $50. Decided to offer him a fifty spot for it.

Down the road what do you guys think would be a better use for this amp? Bridging it and putting 200 watts into my center, or just using it to power my surrounds? With bridging I have read that it can cause a loss of clarity. Plus this would be for HT duty, and I could run into trouble with whatever new amp I get for my fonts not matching up well.

I guess the other option is to just sell it when I get upgraditis and make a few bucks.

tonyb

You could still use it for your center, but I wouldn't bridge it though. This is for HT, you won't have any issues with whatever other amp you buy for the front left and right.

You can also keep it to power the surrounds and find a 3 channel amp for the fronts.

EndersShadow

I think @ZLTFUL has a AMC amp, maybe even that model....

dr1978

Finally got the AMC put in place.......eh. I'm straining to hear any real improvement. I didn't listen to much 2-channel when I was just using my AVR, so I can't make a great comparison, but it seems like I'm turning up the dial even more than I did before. If I listen closely I can convince myself that I'm hearing some increased depth and detail, but again, I didn't really listen to 2-channel all that critically in the first place.

I'm going to give it some more time, but right now I am thinking of going down the 3-channel path and using this for my surrounds. My issue with that is my "rack" is really more of a decorative piece that I purchased as a compromise with my wife that matches our decor. Because of that I have serious size restrictions. If either the width or depth isn't <15.5" then it won't fit. I don't really have the room for a separate amp stand either. So unless I magically come across a moderately sized, affordable, 3-channel amp then I'll just have to wait until I earn enough additional brownie points and can get a real rack.

tonyb

Could just be a bad match. I would look at the input impedance of the amp, and compare to the output impedance of the receiver. Most receivers will have a 1mv output, but many amps may have a 2mv input. Which means the receiver can only drive that amp to half it's power.

Most pre-amps have outputs high enough to drive any amp, which is why the combo of a pre-amp/amp is usually preferred.

What model is the amp ?

dr1978

AVR is Marantz SR5011, Amp is AMC 2100.

I'm having a hard time finding the input and output impedance of the amp and avr respectively.

WLDock

The amp has a 1V input sens. https://www.hifiengine.com/manual_library/amc/2100.shtml

however, the AVR spec does not seem to be listed. I would think its at least 1 volt? You could always check the output voltage of the AVR yourself.

http://www.hometheatershack.com/forums/home-theater-receivers-processors-amps/35677-gain-structure-home-theater-getting-most-pro-audio-equipment-your-system.html#post317692

tonyb

That's actually a good thing the amp has that low of an input impedance, means your receiver should drive it fine to full power. I'm assuming you have it hooked up to the front left and right pre-outs of the Marantz ? If so, with what cables ?

mhardy6647

You guys (and I know you know this!) are talking about source voltage output and load sensitivity, not source/load impedance, in the posts above. All of the above is true, and important -- but it is also true that appropriate alignment (shall we say) of source (output) and load (input) impedance is a good idea.

The old rule of thumb is that the input impedance of the power amp ("load") should be at least ten times the output impedance of the preamp ("source"). The question is, can the OP find the input and output impedance ratings for the components in question.

There was a recent thread at AK on (sort of) this same topic. It might be worth a look, but like so many discussions there in the past couple of years, it sort of degenerated into an off-topic "urinating contest" along the way PM me if you want a link.

You can also try Steve "Decware" Deckert's white paper on the topic (typos and all), if you like.
http://www.decware.com/paper55.htm

alucididea

I’ve got a question on this subject. I just got the following hardware:

Yamaha RX-A3070:
• Rated Output Level / Output Impedance
PRE OUT
SUBWOOFER (50 Hz) ................. 1.0 V/470 Ω ExceptSUBWOOFER(1kHz)..........1.0V/470Ω
ZONE OUT ................................... 1.0 V/470 Ω
• Maximum Output Level
PRE OUT/ZONE OUT ..................2.0 V or more

NAD M22:
Input Sensitivity ............. 1.6 V (ref. Rated power)
Input Impedence ........... 17kΩ + 200pF

This seems like a decent match, however I’m a bit confused by the specs. Does this mean it has a minimum 1V output with a maximum of 2+V? I was hoping you could help me make sense of the specifications. Thanks in advance.

tonyb

alucididea wrote: »

I’ve got a question on this subject. I just got the following hardware:

Yamaha RX-A3070:
• Rated Output Level / Output Impedance
PRE OUT
SUBWOOFER (50 Hz) ................. 1.0 V/470 Ω ExceptSUBWOOFER(1kHz)..........1.0V/470Ω
ZONE OUT ................................... 1.0 V/470 Ω
• Maximum Output Level
PRE OUT/ZONE OUT ..................2.0 V or more

NAD M22:
Input Sensitivity ............. 1.6 V (ref. Rated power)
Input Impedence ........... 17kΩ + 200pF

This seems like a decent match, however I’m a bit confused by the specs. Does this mean it has a minimum 1V output with a maximum of 2+V? I was hoping you could help me make sense of the specifications. Thanks in advance.

You'll be fine, the Yamaha has 2v on the preout and the amp has 1.6 on the input. Your kosher...

alucididea

tonyb wrote: »

You'll be fine, the Yamaha has 2v on the preout and the amp has 1.6 on the input. Your kosher...

So I will be getting the full power from my amp?

dr1978

Well I finally did what I should have done in the first place and did a comparison with and without the amp. I'm getting deeper bass and maybe overall fullness, but it's not enough of a difference for me to settle on. I'm happy with the pickup at the price, but I'll be in the market for another 2 or 3 channel amp.

dr1978

tonyb wrote: »

That's actually a good thing the amp has that low of an input impedance, means your receiver should drive it fine to full power. I'm assuming you have it hooked up to the front left and right pre-outs of the Marantz ? If so, with what cables ?

Yep, it's hooked up correctly, and the cables should be ok. I picked up some blue Jean interconnects.

deronb1

Sorry to hear about the amp. Rarely read about bad experiences with Parasound. I had a 1500a that was fantastic. Kinda wish i still had it.