Amp protection lights on

[PWRmx24]

So the LSi15s handle up to 250w and are 4 ohm speakers. What about the NAD C 268? Thats more in my price range. But its low on watts. I can get a RB-1080 for $700.

 

[PWRmx24]

I see a lot of those RB-1080s and RB-1090 and RB-991s and RMB-1095s around still kicking after all these years so they cant be that bad.

 

[PENG]

I see a lot of those RB-1080s and RB-1090 and RB-991s and RMB-1095s around still kicking after all these years so they cant be that bad.

The Hypex or Purifi suggested are your best bet for those LSI speakers. Without knowing what you actually "power" (almost useless term, but..) requirement is, it is hard to say which model would be suitable, but Polk rated them for 20-300 W (dynamic) so the low cost NC502MP will be able to get them to sound their best.

Class AB amp will do the job too of course, something like the Monolith's 200 Wx2 8 ohms will do but the recommended class D amps will be better if you really want to push them to their limit. All amps (AB, A, or D) rated more than 200/300 W 8/4 ohms with THD<0.01%, 20-20,000 Hz in the price range $1,000 to $infinity will sound virtually the same for those speakers. There are just too much BS/hearsay on the internet so, to save time and money, it is best to stick with specs and measurements that are at least consistent, repeatable, provable facts.

 

[Golfx]

Hi again—you came to this forum for advice. All forum members, so far are recommending you buy and use Class D amps. Engineering science and applications have moved forward onto Class D amps. Are you still wanting old used AB amps? Why?

 

[everettT]

Ok so are you all telling me I'm wasting money on a used Rotel RB-1080 or 1095 or 991 and can get a brand new unit that's as good or better sounding for the same or less $ that will last as long?

Absolutely . If going with a small package and no heat sinks, I'd recommend the Purifi first as their modules produce the least amount of heat based on studies from top reviewers, ones that are only interested in science and not fluffy buzzwords. This is not to say the others will have issues, just playing the very long game personally.

 

[Trell]

Hi again—you came to this forum for advice. All forum members, so far are recommending you buy and use Class D amps. Engineering science and applications have moved forward onto Class D amps. Are you still wanting old used AB amps? Why?

If I would buy a new amplifier then a good class D is what I most likely would buy, and as @everettT wrote low heat generation is important to me as well. Also note that an efficient power supply is very important as well as most of the time the amplifier will output low power (1-5 watt or so). I look at idle power as well as standby power as important factors when buying something as that is the state the device would be in most of the time.

That said, I'm only using an Denon AVR that has the amplification I need, but has class AB amps.

I do have two Genelec 2.1 setups that have internal class D amps. The alternative was active monitors from Neumann but they use class AB internal amps that uses much more power and produces much more heat. So, that was an important part of my reason to buy Genelec. The most important part of not buying Neumann a few years ago was that their room EQ and setup software was of flaky beta quality at that time, reading from posts on ASR.

Both Genelec and Neumann makes excellent active monitors.

 

[PWRmx24]

Thanks for all the comments. I spent some time reading and watching Gene's reviews and articles here on the improvements of Class D amps. Pretty cool that the tech has advanced. I'll think it through. My budget is in the $1,000 range for 2 channels. Maybe I can find a unit that incorporates the Purifi module in that range.
Someone mentioning "power requirements". I've probably outlived the topic of this post.....but I just know the RB-1080 and RMB-1095 do what I want for now in 5.1 or 7.1 use. I use the RB-1080 for the F LRs and the 1095 for the others. Regarding the sound level comment, the sound doesn't seem to "come alive" until my Rotel RSP-1570 is at the 60 (of 100) setting in a 20x13 ft room and I don't see a need to go above 75 ever.....whatever that means. I don't have any leveling settings.

 

[Golfx]

Thanks for all the comments. I spent some time reading and watching Gene's reviews and articles here on the improvements of Class D amps. Pretty cool that the tech has advanced. I'll think it through. My budget is in the $1,000 range for 2 channels. Maybe I can find a unit that incorporates the Purifi module in that range.
Someone mentioning "power requirements". I've probably outlived the topic of this post.....but I just know the RB-1080 and RMB-1095 do what I want for now in 5.1 or 7.1 use. I use the RB-1080 for the F LRs and the 1095 for the others. Regarding the sound level comment, the sound doesn't seem to "come alive" until my Rotel RSP-1570 is at the 60 (of 100) setting in a 20x13 ft room and I don't see a need to go above 75 ever.....whatever that means. I don't have any leveling settings.

The differences between NcoreX and purifi are so small there will be no audile differences.

 

[everettT]

Thanks for all the comments. I spent some time reading and watching Gene's reviews and articles here on the improvements of Class D amps. Pretty cool that the tech has advanced. I'll think it through. My budget is in the $1,000 range for 2 channels. Maybe I can find a unit that incorporates the Purifi module in that range.
Someone mentioning "power requirements". I've probably outlived the topic of this post.....but I just know the RB-1080 and RMB-1095 do what I want for now in 5.1 or 7.1 use. I use the RB-1080 for the F LRs and the 1095 for the others. Regarding the sound level comment, the sound doesn't seem to "come alive" until my Rotel RSP-1570 is at the 60 (of 100) setting in a 20x13 ft room and I don't see a need to go above 75 ever.....whatever that means. I don't have any leveling settings.

I don't know how to say this any more clearly, the modules listed are much better suited for your speakers demanding load. Not that Rotel is bad, but these will give everything you need without effort.

Here are the bad with your speakers.
"Impedance reaches a minimum of 2.02 ohms at 94 Hz and a phase angle of -43.97 degrees"
That is brutal with moderate volume and unless you're crossing over to a sub at 300hz, the modules listed are best to handle that load, easily.

Polk LSi Speaker System HT Labs Measures

HT Labs Measures: Polk LSi Speaker System This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the LSi25 L/R (purple trace), PSW650 subwoofer (blue trace), LSiC center channel (green trace), LSiFX side surround channel (red trace), and LSi9 rear...

www.soundandvision.com

The same applies for your model...

 

[PWRmx24]

Evertt,
When you say "modules", I take that to mean the "brains" of the amp that can be used by different manufacturers. Kind of like the same Intel processor being in an HP laptop or a Dell desktop computer. The modules recommed in this thread are the Hypex NC (what designation omes after that?) and the Purify (what designation comes after that?).
I'm guessing the designation is impotant.

I noticed on the Buckeye site lists "Power" then "Fidelity". "Power" shows a THD of 1% and "Fidelity" show a THD of .0006%.

 

[PWRmx24]

 

[Golfx]

View attachment 71344

you need to read a review from Audio Science Review and look at the power graph ”knee” bend upward into distortion. There is very very little difference in power ratings between 0.01,0.1, & 1.0%. These are light years ahead of rotel‘s numbers.

Hypex NCx500 Class D Amplifier Review

This is a review and detailed measurements of the Hypex NCx500 NCOREx reference design amplifier. It was sent by the company and kindly assembled by our local expert, @Rick Sykora. As you see the sample is a "monoblock" configuration (one channel) driven by Hypex SMPS1200 switching power...

www.audiosciencereview.com

Read through this review it is a master class in how to design an amplifier. You are trying to understand and what you are asking would take a very long post just to help with the definitions of the terms. You may have to just trust our knowledge. We are trying to help you not make mistakes and buy the best amp for the money.

 

[everettT]

Evertt,
When you say "modules", I take that to mean the "brains" of the amp that can be used by different manufacturers. Kind of like the same Intel processor being in an HP laptop or a Dell desktop computer. The modules recommed in this thread are the Hypex NC (what designation omes after that?) and the Purify (what designation comes after that?).
I'm guessing the designation is impotant.

I noticed on the Buckeye site lists "Power" then "Fidelity". "Power" shows a THD of 1% and "Fidelity" show a THD of .0006%.

Yes, the modules are the amps. The way Buckeye list their power is typically, with power allowing for a higher THD.

 

[PWRmx24]

Thanks guys.
So make sure I see this right.....
Buckeye, the company, uses Hypex NCORE or Purifi Eigentackt modules. Other "manufacturers" (like Appolon or ATI) can choose to use the same modules. Is the NCore x the follow (improvement) to the NCore?

I posted the picture from the Buckeye website because I'm not familiar with two THD numbers. One power and one fidelity. I've always seen just one. e.g. Rotel flyer stated all channels driven THD .06% for my RB-1080. So I was confused to see a THD 1%

If I get a Buckeye amp I don't see a need for the massive power rating of the NCorex 500 (700 watts at 4ohm) for my LSi15s rated to 250watts. (Which I have 2 pair, 4 total)
The Purifi 1ET6525SA is 450w at 4 ohms. But they are within $100ish of each other.

If i go with Buckeye I like the idea of having a three channel for my LCR. Then use my Rotel amps (1095 and 1080) for the others until they eventually die I guess.

 

[PWRmx24]

Seems like 20ish years of flawless performance from the 1095 and 1080 is a good run though.

 

[everettT]

Thanks guys.
So make sure I see this right.....
Buckeye, the company, uses Hypex NCORE or Purifi Eigentackt modules. Other "manufacturers" (like Appolon or ATI) can choose to use the same modules. Is the NCore x the follow (improvement) to the NCore?

I posted the picture from the Buckeye website because I'm not familiar with two THD numbers. One power and one fidelity. I've always seen just one. e.g. Rotel flyer stated all channels driven THD .06% for my RB-1080. So I was confused to see a THD 1%

If I get a Buckeye amp I don't see a need for the massive power rating of the NCorex 500 (700 watts at 4ohm) for my LSi15s rated to 250watts. (Which I have 2 pair, 4 total)
The Purifi 1ET6525SA is 450w at 4 ohms. But they are within $100ish of each other.

If i go with Buckeye I like the idea of having a three channel for my LCR. Then use my Rotel amps (1095 and 1080) for the others until they eventually die I guess.

I'd go for the NcX or Purifi in the larger case for 3ch but definitely call (or email) them and explain your setup and they will make sure you get the proper setup for your gear.

 

[TLS Guy]

Seems like 20ish years of flawless performance from the 1095 and 1080 is a good run though.

Not particularly. 20 years is nothing special for an amp. If we were talking sixty years that would be of note.

Plenty of those Rotel amps have blown in just the manner yours has, including the one I was asked to look at, but I can't lift as it is nearly 100 lb. If you think that is good satisfactory design then I want to know what you are smoking. It is bad design and that is the end of story.

The great designer and forward thinker said that " you could measure human progress by performance per pound." On that basis alone your Rotel amp is a massive failure.

I attended one of his lectures when he visited the University of North Dakota. He started his lecture as was his custom of standing on a geodesic structure made only of this wire and matchsticks.

You have received a lot of good advice, here, either take it, or stop wasting people's time. This thread has gone on too long.

 

[PWRmx24]

Merry Christmas TLS Guy.

 

[PWRmx24]

Thanks to everyone who took time to share their opinion. I've learned a lot on this thread and will keep learning from you all.

EverttT, I did email the Buckeye folks and look foward to their response.

 

[PWRmx24]

I've pretty much narrowed my choices down to the Buckeye 3 channel Hypex NCx500 or Purifi 1ET6525SA ("2nd gen Eigentakt") for my LCRs and then demote the Rotel RB-1080 (2 ch) and RMB-1095 (3 good channels left) to the surrounds until they die. The NCx500 power supply has active PFC and Dylan seemed to indicate in a YT video the Micro Audio power supply on the NCx500 may have better components. As you guys mentioned, sound wise, not sure I could tell the difference between these two amps with my Polk LSi15s (LR) in 2 ch music listening or movie watching with Polk LSiC and LSi15s (yes I have four of them) and LSi9s for surround. The Purifi 3 ch he is building right now has the Hypex SMPS1200A400 which is the same PS in the 2 ch or 3 ch which seems good for the 2 ch but probably fine for the 3 ch. The price diff between the two is negligable.