Calling all Polkies:Official Polk thread - Page 474

Amps are designed for one primary application regardless of home, studio, or pro use: Take an input and faithfully reproduce it with gain.

There is nothing wrong with the Crown XLS Drive Core. I've AB'd to my Parasound and you would be extremely hard pressed to tell me which is which with out seeing the one that is currently hooked up.

You can't compare weight. You can't directly compare topologies. Class A / AB are extremely inefficient designs. They require large capacitance banks and transformers to get the job done and some can run only around 30% efficient while Class D can run upwards of 90%. So you have inexperienced and unknowledgeable people comparing items like weight and capacitance (uF).

Class D actually solves the problems that class A/AB presented: Lack of efficiency and weight.

Lastly: You can go to Guitar Center, pick up a Crown XLS 1500 or whatever and have 30 days with it. Return it no questions asked. You don't need a review when you can get ears on.
Edited by Jinjuku - 7/8/12 at 9:04am

Jin:

I dont know how I can be any more neutral than what I posted. Have I personally listened to a Crown amp in my setup...NO. Have I heard what a Crown amp sounds like.... YES. My uncle who I just visited in WI has been running sound for a long time using Crown amps so I am familiar with how they sound and the noise the fans can produce.

You will notice I told the OP you will get opinions one way or the other and then I stated my opinion..... with caveats that it was that at the beginning and end of the post... what else do you want from me?

I simply stated my opinion, which I am allowed to. I didnt present it as truth, didnt say 99% of people do this, ect. I simply stated my opinion, why must you follow me and everytime I post about pro amps quote me?

Why do you need to always quote anything I say about pro amps? Jesus man, stop following me acting like the "pro-amp fan club".

Thanks for the info. I already know I'm going to need a dedicated amp for my mains as my aging yamaha htr-5250 routinely shuts down in protective mode if I try to push it. I have a cerwin vega LW-15 sub that I'm reasonably happy with for now but don't think I'm interested in the 9's as I like towers for my mains. I prefer to listen to music in surround (though I've never had GOOD mains) and already have some RTIa stuff so I will probably be mostly in that line. In your opinion would 15's for mains mesh well with RTIa everything else or would I be better off with A9's and keeping everything in the same line?

How about a no BS A/B of a very reasonably priced Crown XLS-1500 or Yamaha PS2500 which are two amps recommended for their feature set and fidelity in your setup vs your Carver? You have opinion but real zero facts and/or competent experience however to back that opinion up. One potential problem is you see the latter sentence as a slam vs a learning opportunity. How about an opinion based on a side by side comparison? I'm not asking anyone to do anything that I haven't done before.

Up to the point:

1. Offering to bring one next time in Indianapolis have a good time and put one in your setup

2. I believe I have offered you in the past a free Parasound HCA 1000A if you wanted to come down and A/B it vs my XLS 402D. With the caveat you could pick the Parasound out as 'superior'. And again have a good time, cook out etc.

Notice no one is saying to go out and just pick any old pro-audio oriented amp out. As a matter of fact the last GTG of PartsExpress Tech Talk members a Crown ComTech was used. The one I attended was a Hafler. Every single speaker there (about 14) were from the ground up designs. All of them actual speaker designers and x-over gurus.

People are allowed their opinions. Even improperly informed ones. Note that I am not saying that when you hear your Carver and say the Yamaha or Crown that with a towel thrown over the stack you won't be unable to form an opinion. At least you will have a bone of experience that you can wade in with.

I do however have a concern that you have noise on one channel of your Carver. Does it switch speakers if you swap inputs from the pre? Does it switch speakers if you swap the outputs?

Quite simply: You're currently dangerous in that regard.
Edited by Jinjuku - 7/8/12 at 10:48am

The noise does not switch channels when I switch inputs. I haven't tried to switch the speaker cables as they are a PITA to switch as the M1.0t accepts ONLY bare wire and I have enough trouble getting the current speaker wires connected lol. The noise isnt horrible, its just something you pick up on a bit when the AVR is muted. I know this amp is known for having some slight noise if its not been serviced.

I plan to have this amp serviced to have its capacitors replaced (the SN on this amp and transformer indicate it was built in 89), as well as get the now standard 5 way binding posts installed so I can use banana plugs. That should fix what I am hearing now.

Hopefully I will get it serviced soon so its good for another 30 years.

Wow man. You need to chill out a little when talking to grown men brother.

Feel free to quote me where I have been argumentative. Seriously.

Can we go back and talk about Polk speakers?

I know right? Every time this "member" gets involved, the thread gets derailed, EVERY TIME.


ROFLMAO, that's because you haven't had a sub in what, 500 years? Come on over Enders, I'll let you stand right in between my dual 15"ers.

I'm watching IM2 last night and my No Cell Phone sign fell off the back wall. This is at +3 with just over 1/4 gain. Can't describe it, just come over.

Yep and every time I see some fantastical BS about amplification this 'member' is going to call it. Get used to it I guess.

I see the Onkyo 3009 that i have is class B. Why do companies go with class B instead of class D in your option. is it because they are in expensive?

Some pics of the new Carver amp internals are here.

I havent totally worked it into my rack yet so no new pics of that just yet

I can't wait till I purchase my QSC pro amp. I hate this thread but love it at the same time . Glad your enjoying the speakers.

Question, I don't see a 12 volt trigger on the Carver from pics...is there actually a 12V trigger that I'm not seeing? I think I will have to get one of those green Belkin strips for the amps I'm getting because they don't have 12v triggers.

I can pull the 12v trigger from my Integra receiver to the APC H15 and I believe configure it so that when the Integra goes off it turns off the high current outlets on the APC H15 which is what my amps are on. I need to do some more research to make sure I can make that happen however....

I'm really excited to hear how the Pro amp works with your setup. I've never used one for a HT or home music system. The only exposure I have with Pro amps is with pro sound boards and guitars.

I think the Onkyo NR3009 is a class A/B. The manual talks about FCC Class B digital device which is:

"Class B Digital Device. “A digital device that is marketed for use in a residential environment notwithstanding use in commercial, business and industrial environments. Examples of such devices included, but are not limited to, personal computers, calculators, and similar electronics devices that are marketed for use by the general public".

Most higher end "audiophile" style amps use Class A or class A/B push-pull amplifiers due to their amplification fidelity. Class As are on 100% of the time and use the full 360 degree sine wave (very inefficient). Class B amps are only 180 degree push pull amps (slightly more efficient due to 50 on/off time) but have crossover noise filtering problems. A/B amps combine the best of both.

D class amps are very efficient and lightweight and provide excellent sound quality for most any application. They do, however, (and this is where the preferences come into play) convert PCM digital signals to PWM signals. There is an inherent loss of fidelity, arguably negligible though, and is probably why some don't use them. I have class D amps in three or four sound systems (although not high end) and they sound great.

When I have been exposed to and had to set up Pro amps for bands, concerts, and pro building sound systems, I have always been curious how they would work in the home. The only thing that has prevented me from going with pro amps are the input requirements, which can be a little different than my home setup.

That is an incredibly clean looking amp inside. Those are some big ol' caps you got there brother. Looks like te 1F cap I have in my truck for my sub... LOL

Expense doesn't have really anything to do with it. Engineers make design choices all the time. Wyred4Sound has some class D stuff that will cost you a good chunk of change and so does NAD. Pioneer uses Class D as an example also.

Class D was one of the harder topologies to get done correctly which is why you tended at the start to see it only from big outfits that had the manpower to engineer it. Since then it has trickled down.

Crowns class I spec is really interesting in that the spec features some of the best of both the class A and class D world. It's a push push output stage (so like Class A no cross over distortion) and light weight with decent efficiency like Class D plus high power handling. Their top end iTech HD will set you back about $5-6K.

The 3009 is indeed a Class AB amplifier. The Onkyo website shows a "dual PUSH-PULL" design. Dual push-pulls are AB (one NPN and one PNP transistor amplifier).

I have a QSC CX902 amp laying around, I'm gonna try it with my RTi A9s this week. I'll put some impressions and comparisons between the QSC and my XPA-3. First thing I need to order two XLR - RCA adapters

The Carver has the looks like a Class D amp
Edited by Jinjuku - 7/8/12 at 5:28pm

That is one of their multi-format models (70v distributed audio). The GX/RMX/PLX series would be the ones to use. But give it a whirl. Be interested to hear your thoughts after gain matching.

I got three RMX 4050HD and two RMX 2450 for my church. Those are really good amps but are too noisy. You can hear the fans running even at 20 ft apart from the amps. CX amps are the most quiet from QSC, also the more expensives.

That is why the amps should be installed in a utility closet somewhere. For house hold use fidelity isn't a concern but placement is. Yamaha, Crown, AB International etc... all make amps that can sit on the shelf in your entertainment room and be 100% silent.

We've done whole house A/V installs with Crestron and covered the Home Theater, the Two Channel Room, Kitchen and back yard all from one equipment rack tucked out of the way.

Are there any other centers that would match my RM6750 set ? Ideally I would like to just replace the center without having to get new fronts. Realize the front three need to match and was hoping that another Polk center could work. Use is primarily tv/movies and some Wii, very little music if that changes anything.

Thanks in advance,
Chris

The matching center for the RM 6750 set is the RM 6752. You can find it here:

http://www.amazon.com/Polk-Audio-RM6752-Channel-Speaker/dp/B0009X09IQ/ref=sr_1_1?s=electronics&ie=UTF8&qid=1341852708&sr=1-1&keywords=rm+6752

http://www.ebay.com/itm/RM6752-Titanium-RM6750-Center-Channel-Polk-Audio-/360462816058#vi-content

Hi Enrico,

I know that's the one that is currently in my 6750 set, but was wondering if I could replace the 6752 center with a larger and better center without having to replace the fronts.

Thanks again,

Chris

Can you: Yes. Should you: No

If you replace your stock center with a bigger one you will get higher dialog at lower volumes, but find that the special effects (which mostly come from your Left & Right speaker) underwhelming because they cant keep up with the center. Just like if you replace your Left and Right speakers with big towers and keep the center really really small you will get great effects, but hard to hear dialog.

When I first started out I purchased Monitor 60's for my left & right to replace the HTIAB fronts I had. I wanted to wait to get the center for a bit. I was watching "The Matrix" and everything sounded GREAT, until dialog came on. I found myself cranking it to hear people talking, then having to turn it waaaayyyy down when effects came on. You dont want to have to do that 24/7, its no fun. Needless to say 30 mins into the movie I had ordered a matching center from newegg .

You normally want to have your center and fronts matched within the same series of speakers so for instance TSi Fronts with a TSi Center, as this way they are timbre and SPL matched closely.

If you wanted to step up and not spend a fortune I would suggest Monitor 30's for your Left and Right and a Polk CS2 for your center. That would be a big improvement over what you had for not a lot of cash. You could also get the Monitor 40's for your fronts, but they cost more .

Check newegg often as they run specials on the Polk Monitor series all the time . Happy Hunting.

Thank you very much, that is the info I was looking for. Figured it would not be that easy to just switch the center but figured I would ask first.

Any thoughts as to whether the TLs are noticeable better than the 6750, or am I just going from one small set to another and likely to run into the same issue ?

Cant answer that one as I have no experience with them. I do know the Blackstone's are getting some good reviews from folks that are using them.

I personally went directly from the Monitor series to LSi's but thats QUITE a bit more than I think you want to spend .

OK my setup...

TV - Panasonic Viera GT55 3D Plasma
Receiver - Yamaha RXV671
XBOX 360 (also still rockin the HDDVD too)
Panasonic 3D Blu-Ray
Apple TV (gen 2 with 1080p)

Speakers
Front Main - Polk Monitor 60 Series II
Front Center - Polk Monitor CS1 Series II
Front Presence - Polk TSi100

Sub - Polk PSW110

Surround - Polk Monitor 40 Series II
Back Surround - Polk TSi15