Which Emotiva amp for stereo listening?

[RichB]

Isn't it the- chocolaty bass and the highs full of vitality, while the mids have much more depth and richness...

Milk chocolate don't bother.
Dark chocolate, that's a keeper

I am still in search for the "heft and last bit of air and openness" that many reviewers find only in amps costing 10 x as much

- Rich

 

[mister wiggles]

Well, the midrange has more clarity, depth, and richness, but the highs are usually smooth, sweet, chocolaty, and the bass is usually faster, punchier, meatier, deeper, more powerful.

And the soundstage just really opens up.

And...and.... the imaging is more precise.

Yep, my speakers really sing when being fed with mono-blocks.

I'm typically on the delivery end of sarcasm. As I suspect i may have fallen victim in this instance, I am requesting clarification.

 

[ImcLoud]

Nothing to do with you, we were just being funny, you only have 23 posts, we won't have fun at your expense until at least 25 posts... Sime of us think its funny that some reviewers find nuances and hidden magical material once they hook in a $20K set of bookshelfs and a $15K amplifier... And how they word it is funny to read sometimes.... Not all reviewers do this, just the really good ones...

 

[AcuDefTechGuy]

I'm typically on the delivery end of sarcasm. As I suspect i may have fallen victim in this instance, I am requesting clarification.

Yeah, just attempting humor.

As I've said before, I don't think there are any audible advantages of mono-block amps.

 

[ImcLoud]

With sterep listening mono blocks are nice "just because", but for HT and your front 3 I would get the xpa3...

 

[mister wiggles]

okay now that we've gotten the mono vs multi channel debacle out of the way. How do i determine how much power i need to my speakers before SQ benefits diminish?

The XPA-3 makes sense but another but the larger power supply and another 100wpc in the XPA-2 is awfully tempting. That and i'm not sure how much the htm4s center will benefit from more power for HT usage. Any way to tell from the numbers or do i need to listen 1st hand and decide?

If the XPA-3 works, why not get the 5 and drive the rears too?

 

[fuzz092888]

I may have missed it, but what size space are you trying to fill?

Either the 3 or the 5 would be fine. What you can't forget is that for HT, the shared power supply means that an individual channel or pair of channels can get much more than the rated power for a period of time. This is important because in real world content you will probably never run into a situation where all channels are demanding full power. This means that a lower powered multi-channel amplifier might perform better for HT use than a dual mono or mono-block amplifier.

 

[ImcLoud]

I use an xpa5 for my ht but that is because I run a processor, if I had an avr and needed more power, I would run my surrounds off of the avr and the front 3 off either 3 apa150's or an xpa3 depending on if I needed the extra 50w per channel... 3 apa150s costs 375 which will give you 150 wpc, the xpa3 is almost double that and only gives you an extra 50wpc, which as we all know the higher you go the less the numbers mean {I know I didn't say that rite} but in terms of db 50 watts comparing 10 w to 60w is a big difference but when comparing 200w to 250w its not as substantial... So if you just want to take some pressure off of the avr, 3 apa's should do it just fine, I used to run a system with 4 apa150s {3 mono''d to the front end and 1 split for the surrounds} and it worked great...

 

[AcuDefTechGuy]

How do i determine how much power i need?

First, you get out a good SPL meter and measure the PEAK volume you listen from your listening distance (10ft = 3m).

The 804s has a sensitivity of 90dB/2.83v/m & minimum impedance of 4 ohm, nominal of 8 ohms.

If listening distance is 3m and total peak volume is 94dB (for me personally in 2.0 Direct mode), each speaker needs 11 watts (8 ohms) or 22 watts (4 ohms).

If peak is 97dB, then it's 23 watts/8 ohms or 46 watts/4 ohms.
If peak is 100dB, then it's 45 watts/8 ohms or 90 watts/4 ohms.
If peak is 103dB, then it's 100 watts/8 ohms or 200 watts/4 ohms.

If your measured peak Volume is the same as mine, which is 94dB, then add 9dB more if you want to feel really "safe" = 103dB.

So then you need about 100 watts into 8 ohms for the "nominal" impedance and 200 watts into 4 ohms for the "minimum" impedance.

In conclusion, you "WANT" an amp that can deliver 200 watts into 4 ohms, even though you only "need" 22 watts into 4 ohms. So any amp that can deliver 200 watts into 4 ohms or more is good.

 

[mister wiggles]

I may have missed it, but what size space are you trying to fill?

Either the 3 or the 5 would be fine. What you can't forget is that for HT, the shared power supply means that an individual channel or pair of channels can get much more than the rated power for a period of time. This is important because in real world content you will probably never run into a situation where all channels are demanding full power. This means that a lower powered multi-channel amplifier might perform better for HT use than a dual mono or mono-block amplifier.

Room is 20x28x12. the entire floor is open. I don't expect to fill the room with music, but listening distance is about 10ft.

 

[mister wiggles]

Thanks for all the great input guys.

I'm going to look for an XPA-3 to drive the front LCR. Depending on how happy I am with the setup, I may add a 2 channel amp to drive the front LR and rededicate the XPA-3 to drive the center and surrounds.




Found these on local craigslist. Any thoughts

Rotel 1075
Home Theater System Surround Sound Amplifier DVD Player - Rotel PRODUCT SPECIFICATIONS

Crown CTS600
CTs Series

 

[fuzz092888]

Thanks for all the great input guys.

I'm going to look for an XPA-3 to drive the front LCR. Depending on how happy I am with the setup, I may add a 2 channel amp to drive the front LR and rededicate the XPA-3 to drive the center and surrounds.




Found these on local craigslist. Any thoughts

Rotel 1075
Home Theater System Surround Sound Amplifier DVD Player - Rotel PRODUCT SPECIFICATIONS

Crown CTS600
CTs Series

That would be fine, and I think the the 2 channel for the L/R and the 3 channel for the center and rears is a great idea. It's kind of like what I have now.

The Rotel 1075 is an awesome amplifier. Don't let it's power rating fool you, it's a beast of an amp. If we compare it to the XPA-5, the rotel has half the power rating, but a larger transformer and more capacitance, which points to a conservative rating and one that sounds more fuse limited than capability limited. I used to have one and can attest that it's stable into low impedance loads (~2ohms) and delivers lots of good clean power. Definitely worth a look for the right price.

 

[mister wiggles]

Also found a Rotel RB-993 that might fit the bill.
Home Theater System Surround Sound Amplifier DVD Player - Rotel PRODUCT SPECIFICATIONS
http://www.rotel.com/content/manuals/rb993_eng.pdf

Gonna check out the 1075 this weekend. stepping into another greyish area, would utilizing 4 of the 5 channels to bi-amp the L/R speakers have any benefits? the 804's should allow the HP and LP to be driven separately, wouldn't a dedicated channel be better?

 

[fuzz092888]

Also found a Rotel RB-993 that might fit the bill.
Home Theater System Surround Sound Amplifier DVD Player - Rotel PRODUCT SPECIFICATIONS
http://www.rotel.com/content/manuals/rb993_eng.pdf

The 993 is more or less a 3 channel version of the 1095. Good amp, tons of power.

Gonna check out the 1075 this weekend. stepping into another greyish area, would utilizing 4 of the 5 channels to bi-amp the L/R speakers have any benefits? the 804's should allow the HP and LP to be driven separately, wouldn't a dedicated channel be better?

None whatsoever. That's called passive bi-amping, since the passive crossover is still in line, and all the benefits are merely technical or highly subjective. It sounds good on paper, but when you really examine it, it doesn't give you any of the real benefits of having an active crossover, which is what it is trying to mimic.

 

[RichB]

First, you get out a good SPL meter and measure the PEAK volume you listen from your listening distance (10ft = 3m).

The 804s has a sensitivity of 90dB/2.83v/m & minimum impedance of 4 ohm, nominal of 8 ohms.

If listening distance is 3m and total peak volume is 94dB (for me personally in 2.0 Direct mode), each speaker needs 11 watts (8 ohms) or 22 watts (4 ohms).

If peak is 97dB, then it's 23 watts/8 ohms or 46 watts/4 ohms.
If peak is 100dB, then it's 45 watts/8 ohms or 90 watts/4 ohms.
If peak is 103dB, then it's 100 watts/8 ohms or 200 watts/4 ohms.

If your measured peak Volume is the same as mine, which is 94dB, then add 9dB more if you want to feel really "safe" = 103dB.

So then you need about 100 watts into 8 ohms for the "nominal" impedance and 200 watts into 4 ohms for the "minimum" impedance.

In conclusion, you "WANT" an amp that can deliver 200 watts into 4 ohms, even though you only "need" 22 watts into 4 ohms. So any amp that can deliver 200 watts into 4 ohms or more is good.

Hey, that's what I did on this thread and took some serious heat for for it.
So, are you buying into measuring peak volume and inferring power usage?

- Rich

 

[AcuDefTechGuy]

Hey, that's what I did on this thread and took some serious heat for for it.
So, are you buying into measuring peak volume and inferring power usage?

- Rich

Well, my present thinking is that if your speaker's impedance is not lower than 4 ohms, then pretty much any AVR will do most of the time.

But if your speakers go below 4 ohms, then all bets are off since most people don't measure AVRs below 4 ohms. Some AVRs may be able to handle 3 ohms, some may not.

I'm seeing reports of speakers causing AVRs to shut down when the speakers are relatively efficient, except for the fact that the speakers go below 4 ohms at certain frequencies. I can only guess that some AVRs just suck when presented with 3 ohms loads.

I think many external amps will handle 2 ohms just fine, so I am not concerned with running out of external amp power.

IOW, I would be more concerned with amps being able to drive difficult loads than the actual power output if the speaker is a difficult load.

Finally, it's not WHAT you say, but HOW you say it.

I'm just more agreeable than you. Simple as that.

For the love of gods, get over it, man.

 

[RichB]

Well, my present thinking is that if your speaker's impedance is not lower than 4 ohms, then pretty much any AVR will do most of the time.

But if your speakers go below 4 ohms, then all bets are off since most people don't measure AVRs below 4 ohms. Some AVRs may be able to handle 3 ohms, some may not.

I'm seeing reports of speakers causing AVRs to shut down when the speakers are relatively efficient, except for the fact that the speakers go below 4 ohms at certain frequencies. I can only guess that some AVRs just suck when presented with 3 ohms loads.

I think many external amps will handle 2 ohms just fine, so I am not concerned with running out of external amp power.

IOW, I would be more concerned with amps being able to drive difficult loads than the actual power output if the speaker is a difficult load.

Makes sense.

I'm just more agreeable than you. Simple as that.
For the love of gods, get over it, man.

Most of the time...

It's all good now

- Rich

 

[AcuDefTechGuy]

Makes sense.

Most of the time...

It's all good now

- Rich

I'm thinking about buying a Lexus GX460. Do you agree?

 

[3db]

Guys, 4 ohms is not a big deal if the phase angle is small. However, when you get into electrostatics with high reactive components in the impedance, then most AVRs won't do. I rather drive a 4 ohm load with a small phase angle than a 16 ohm load with a large phase angle such as those generated by driving Electrostatics. You need to step out beyond the 4 ohm world now and look at impedance as a whole.


Here's a link


http://www.dummies.com/how-to/content/generalize-impedance-to-expand-ohms-law-to-capacit.navId-407033.html

 

[RichB]

I'm thinking about buying a Lexus GX460. Do you agree?

I weep for the planet. I staying with my more modest RX300.

- Rich