What amp for the RTi 12 [Archive]

starflight

12-29-2007, 12:18 AM

Hi guys,

I just bought a new HT setup with RTi12's as my main fronts. Beautiful beast these. I absolutely love them but I find that my Yamaha RX-V2600 is not giving as much as these things can eat up. My receiver amp is giving 130WPC but these things can handle up to 500Watts!!!!

so I'm considering Behringer A500's, 2 of them running bridged Mono that should give 500W @ 8 Ohms. This will run me about $400 for the two no tax, free shipping. or as others have suggested, get the bigger beasty Behringer EP2500.
Not sure what you guys think of these two amps. I just want to make these puppies sounds as good as they can and I know that extra power will help. I appreciate your assistance.

Starflight
*******

Yamaha RX-V2600 Receiver
Viewsonic PJ503D DLP Projector
Fronts: Polk RTi 12
Center: Polk CSi 5
Side surrounds: Polk RTi 6
Rear surrounds: TBD
Sub: Polk PSW10
Sony PS2 Slim modded

zingo

12-29-2007, 02:49 PM

Behringer is a "budget" pro audio company. It's not unheard of to have a good system that includes a pro amp, but the A500 is cheap for a reason. It is not a hifi amp, and you can do a lot better. I have not heard the EP2500, so make sure you demo one before you buy it. Having pro amp experience myself, here is what I have picked up:
Pro amps provide tons of power and can sometimes be had at a great price. However, they are also noisy in many ways since they are made to be in a loud environment and critical listening may not have been a goal when created. The transformer may have an audible hum, so check that out model to model. Most pro amps have fans, and they can put of quite a noise, especially at higher outputs. And some pro amps just don't sound good. They may be distorted, sloppy, or just lacking clean power. (When you're using them in a club, does that stuff really matter?)
Here is what I did:
I am running a Carver PM1201. It's 600wpc @ 4ohms so plenty of power. The transformer has a hint of a hum, but cannot be heard over the slightest volume when I am using it for my SDAs. I cleaned all the connection on the amp to clean up the sound, then installed a thermal switch so that the fans don't turn on until the amp is really warm. (They usually stay off) One of the things that impress me with Carver is that he built his pro amps similarly to his home amps. They are the same high quality circuitry and sound, but mods a little differently. If you have any questions, feel free cause there is a lot here.
PS. RTi12s are awesome and welcome to the club.

Mike Reeter

12-29-2007, 05:06 PM

I have our 12's bi-amped with a couple of Adcom amps. 200 wpc driving the bottom end (woofers) and 125 wpc powering the upper end (mids & tweeters)

You can pick up very good used amps. from Audiogon.com at a little over half price in most cases.

Amps such as these are a far better choice than any pro amp out there IMHO.

cfrizz

12-29-2007, 05:20 PM

Here are some options for you.

http://buy.audiogon.com/cgia/cls.pl?ampsmult&1203370332
http://buy.audiogon.com/cgia/cls.pl?ampsmult&1202864099
http://buy.audiogon.com/cgia/cls.pl?ampsmult&1204040955
http://buy.audiogon.com/cgia/cls.pl?ampsmult&1204135286

MADGSF

12-29-2007, 05:44 PM

I agree that pro amps are not the way to go for this application. Assuming you have a 400.00 budget, only want to power the RTi-12s and are ok without a remote power on amp I found these on audiogon:
http://buy.audiogon.com/cgia/cls.pl?ampstran&1203008490
http://buy.audiogon.com/cgia/cls.pl?ampstran&1203747615

tonyb

12-29-2007, 05:56 PM

Some good links here that are great choices for you to consider.Forget the cheapo pro amp thing,hardly ever works out well.

Welcome to the hotel....you know you can never leave now...right??

zingo

12-29-2007, 08:20 PM

Just to clarify, I was not suggesting that pro amps would be better in this application then home amps. Both of the amps that he was discussing were pro, and so I thought I would give him the pros and cons of the kind of amps he was looking at.

starflight

12-29-2007, 09:41 PM

Thanks all for the great suggestions. I should have clarified. My budget is about $400. This is why I was considering those Behringer amps. I should say that I spend as much time listening to music as much as I do movies.

Another amp I was considering is the ADCOM GFA-555 at 200WPC @ 8ohms. I've heard some great things about this amp and it was serious consideration but these Behringer A500's at 500W bridged in a mono config sounded like a perfect mate.

I must admit I am very happy with the sounds of the 12's right now. I don't tend to blast music all the time but I do from time to time. In my config, I have the speakers set to LARGE and bass going to both the sub and fronts.

Would these amps mentions above even at 200WPC make that much of a diff from my Yamaha's 130WPC?

cfrizz

12-29-2007, 10:08 PM

That would be an unequivacable YES!!!

BaggedLancer

12-29-2007, 10:43 PM

Don't listen to cfrizz, if you had said 195wpc she would have told you it wasn't enough! :p

starflight

12-29-2007, 11:13 PM

all right so if I'm not going to go for the Behringers my option of choice is Adcom since I have done enough research on them. I found a GFA550 for about $400 after shipping. Thing I do like about this amp is that it has great reputation and in the future if I choose to get a second one and bridge them I would get a whopping 600WPC.. I think that is insane.

Seriously though, I have just spend a few thousand in the last month, so if I am going to fork out another $400 more, I really want there to be a noticeable difference. From all the I have read, it sure sounds like these 12's will gain from the amp.

come on gang,, help me justify the purchase and seal the deal. =)

cfrizz

12-30-2007, 12:04 AM

Go watch your football game!:rolleyes::p:D

Don't listen to cfrizz, if you had said 195wpc she would have told you it wasn't enough! :p

BaggedLancer

12-30-2007, 12:05 AM

Go watch your football game!:rolleyes::p:D

I am!

195wpc is enough.

Sherardp

12-30-2007, 01:11 AM

D-Sonic Magnum 1000S, 525watts x2 @8ohms, 1000 watts x2 @4ohms. Cant go wrong there.

www.d-sonic.net

starflight

12-30-2007, 01:35 AM

D-Sonic Magnum 1000S, 525watts x2 @8ohms, 1000 watts x2 @4ohms. Cant go wrong there.

www.d-sonic.net

Unfortunately I said my budget was $400, not $1400. Looks really sweet though. =)

anonymouse

12-30-2007, 01:53 AM

Did you mean the GFA5500?

starflight

12-30-2007, 01:58 AM

Did you mean the GFA5500?

oops, I mean the GFA-555. It's an older one.

starflight

12-30-2007, 02:05 AM

Well, so the saga of my search for an amp ends, for now. I "accidently" clicked on the Buy It now button instead of the X to close the window. =) The model I just bought is the ADCOM GFA-555 and I can't wait to receive it. Thank you all for your suggestions. I can't wait to receive this unit and plug it in. I will be sure to follow up and give a review of it's match with the RTi 12's.

Although, I'm a numbers kind of guy and feel the urge to see how they will perform in a 2 channel mode on the RTi12's and then bridging it and giving 600W mono to one of them. LOL

Oh it's like waiting for Christmas morning all over again. Oh joy!

Mike Reeter

12-30-2007, 09:56 AM

george daniel

12-30-2007, 10:29 AM

Along with a new amp. comes the need for some "quality" interconnects and speaker cable.

These are also components that will contribute to the final sound,and are the most overlooked.

Let us know your thoughts when the Adcom is in the house.

yep and yep,,having owned a system similar to yours,,you might want to give some MIT T-2 (grey) interconnects and speaker cables a try.They seemed to tame the "brightness" that I felt the adcom 555 had.But, like Mike said,,components,,,Source cannot be overemphasized,just ask some of the long time members.Good luck,enjoy,and most of all have fun,or vice-versa :)

tonyb

12-30-2007, 10:53 AM

The Adcom will serve you well,good choice.But don't get caught up in numbers and bridging one channel.This will most likely empty your wallet with very little improvement and possibly damage your speaks if you have no self control over the volume dial.As others have said,get yourself some decent cables and I/C's,they will make a difference.
Good luck and let us know what you think.Make sure you have some cables on hand to hook it up when you get it.

starflight

12-31-2007, 12:22 AM

Thanks for the additional suggestions about the interconnects. I have already wired all my speakers with 12 gauge speaker cables from KnuKonceptz. Also I have purchased banana plugs from them as well. Every speaker is connect to the back of the Yamaha. The fronts and center also have them as well. The surrounds are bare wire but I think they sound fine for now.

I do noticed that the Yamaha and Polks sounds bit bright but I have the bass dialed to 6+ db and the treble set to -3 db. Sounds good to me. I haven't had the chance to take pics yet, but I intend to once my Adcom and Theater Director surge protector arrive. I'm also waiting for the center speaker stand to arrive. Right now the center is on top of the box it came in....

Just not ready for the camera yet =)

cfrizz

12-31-2007, 01:56 AM

You will need interconnects to connect your amp to the receivers preouts.

tonyb

12-31-2007, 02:23 AM

Just for giggles...where do you have the crossover set in your receiver?

starflight

12-31-2007, 03:11 AM

You will need interconnects to connect your amp to the receivers preouts.

any suggestions on good bang for the buck interconnects?

starflight

12-31-2007, 03:16 AM

Just for giggles...where do you have the crossover set in your receiver?

Good question. I let YPAO do all of the calibration and work. Looking at my setup in the GUI, I see that all the speakers are set to Large, front center and surrounds. Bass Cross Over at 80HZ (THX). Hope this answers your question.

tonyb

12-31-2007, 03:30 AM

starflight

12-31-2007, 03:56 AM

Sometimes when you auto calibrate,you still have to fine tune alittle here and there.To me,80 is too high for the 12's.Try lowering it to around 65 and see if it sounds any better.If not,you can always put it back to 80.Also try setting the 6's in the rear to small.Enjoy the toys.

Thanks. I think that when I let it calibrate, YPAO actually set this to 60 but I manually changed it back to 80 when I was watching a THX movie. I don't have too much knowledge of the cross over stuff yet, but I have set the bass cross over back to 60. I guess this would affect all the other channels and not just the RTi12's right?

I just experimented a little with setting the RTi6's from large to small, but I think I like the sounds of them set to large more but thanks for the suggestion!

Mike Reeter

12-31-2007, 11:15 AM

any suggestions on good bang for the buck interconnects?

Solid cables at an affordable price

http://signalcable.com/index.html

MADGSF

12-31-2007, 02:43 PM

As far as the interconnects go all the above are good suggestions. I ended up with Audiquest Sidwinder which helped tame the brightness of my RTi-10s.

cfrizz

12-31-2007, 07:26 PM

www.bluejeanscable.com

starflight

01-03-2008, 03:55 AM

Solid cables at an affordable price

http://signalcable.com/index.html

DAMN... those ain't cheap interconnects... Is it really necessary to spend close to $40 for a pair of interconnects to an amp?

starflight

01-03-2008, 03:59 AM

thanks for all the suggestions. It seems as though decent quality interconnects in all the brands I have checked out so far, knukonceptz, bluejeans, and signalcable are all around $40.

I understand that better cable has more resistance towards signal interference and perhaps use thicker cable and such but honestly I wasn't planning on spending more than $20 on interconnects.. am I skimping out if I say consider a pair of these....

http://www.knukonceptz.com/productDetail.cfm?prodID=KRY2.1M

or

http://www.knukonceptz.com/productDetail.cfm?prodID=KARSS2.05M

RuSsMaN

01-03-2008, 04:09 AM

starflight

01-03-2008, 04:15 AM

The Adbomb 555 is a cool amp. I've seen two modded, added an extra power tranny and upped the voltage on the rails (with computer grade caps), and it benched at nearly 800w per channel before the wheels shot off.

Gary Dodd set in on fire on a pair of GR Research Alpha line source. I've never heard anything so loud.

Good choice at your pricepoint.

Cheers,
Russ

Hey Russ,

interesting story. Are you saying that if I use lower quality interconnects, i can cause problems to the amp? I am not planning to do any mods to the amps at all. Could you clarify what you consider a good choice at my price point? Thanks.

RuSsMaN

01-03-2008, 04:20 AM

starflight

01-03-2008, 04:25 AM

I didn't say anything about interconnects, and can't imagine any problems rearing their head with a $3 or $3000 pair, sound quality aside.

For four Franklins, the Adcom 555 offers a lot of bang for buck in the power department, you did good.

Cheers,
Russ

Ah that explains my confusion. Thanks yeah I think I got it at a good price. Haven't received it yet though but I am already eagerly awaiting it.

RuSsMaN

01-03-2008, 04:36 AM

You've got a stellar system in the works, take your time, and use your budget wisely (the guys and gals here will help with that). Welcome to the boards, and thanks for choosing Polk Audio!

Cheers,
Russ

revfanbak

01-03-2008, 10:33 PM

Long time car audio enthusiast. I've been looking at the Polk website and Forums for a year+ but never pulled the trigger until recently. On Tuesday I purchased one pair RTi12's(fronts), RTi8's(rear) and a CSi3 for center chanel. I have seen a few high end cars with solid state amps on the subs and tube amplifiers on the mids and tweets. How would this set up work on the RTi12's? Or should I just stick with solid state(transistor) all the way around? I have Carvin (carvin.com) amps and guitars and I know they have "Pro Audio" amplifiers that have very good specs. It looks like the opinion here is that these amps are not good for home audio and home theatre. I used to manage a movie theatre and all amps were QSC, never had a problem with them and they were very explosive. I have never scene them used or posted by anyone on the forum. Any opinions? Also I have not scene anyone on the forum mention equalizers, which in car audio is a must(thirty band, 1/3 octave), worth the extra $ or not?

Mike Reeter

01-04-2008, 09:06 AM

DAMN... those ain't cheap interconnects... Is it really necessary to spend close to $40 for a pair of interconnects to an amp?

Yes,You have paid good money for a great set of speakers and a quality amp.

Why sacrifice the end sound quality with a $1.00 set of p.o.s. i/c's and cables???

ward91

01-04-2008, 09:14 AM

i dont know about Audiogon as i live in the uk a do however know that most of the pro sound industry hate behringer ,and the audiogon will be betther than the behringer as it for a starter will most likley work out of the box (not a doa) and secondly it will most likley last longer than its gaurantee period.

chargerman426

01-05-2008, 12:30 AM

i have a carver M1.5t (350x2 rms, 600x2 for musically significant points into 8 ohms) hooked up to my rti12s and it sound amazing and i picked it up on ebay for like 340 dollers shipped. i just picked up another M1.5t so im going to try bi amping the speakers and see what it sounds like.

starflight

01-12-2008, 03:01 PM

I finally received my Adcom amp yesterday and I hooked it up last night. At first I wasn't able to tell the difference but I recalibrated my setup with YPAO and then set the bass output to the Fronts and all could say was "HOLY SH_T!" These woofers came alive as I expected them too. The bass was soooo good that I had to dial down the bass on the receiver down.

I did some further testing with different music and I'm very pleased with purchase. The amp heatsinks in the back do get pretty warm so I separated it and put the amp in bottom of my rack so that it would not get close to the other components.

I think I read this somewhere before but now I can't seem to find the threat as to where I read this, but I do notice that when I change sources on the receiver or when I go from menu to menu on my dvd player, I hear a light pop coming from the RTi12's that are connected to the Adcom.

Do you guys know what I am talking about? Perhaps I should start a new thread on this. By the way, thank you all very much for your suggestions and help. Currently I'm just using regular interconnects for now but I'm still trying to decide between Bluejeans, signalcable or knukoncepts interconnects.

Would this make a difference in reducing the "pop" sound?

cfrizz

01-12-2008, 05:45 PM

Congratulations SF! Welcome to the wonderful world of separate amplification!

starflight

01-12-2008, 08:02 PM

hi Cfrizz!

Thanks. I'm really looking forward it! Now if only I can sort out this pop sound. hee hee

Mike Reeter

01-13-2008, 10:45 AM

This might help...http://www.polkaudio.com/forums/showthread.php?t=26529&highlight=adcom+thump

starflight

01-13-2008, 03:24 PM

This might help...http://www.polkaudio.com/forums/showthread.php?t=26529&highlight=adcom+thump

Thanks Mike,

that thread was a great read. It surely described my situation but unfortunately there is no solution to the issue. From what I have read the thump the guys were experiencing where from the initial on and off start, but mine "thump/pop" happens each time there is silence to signal.

On Audioholics, someone suggested trying a ground loop isolator... what do you guys think?

By the way, I just ordered a pair of Bluejeans Interconnects. Can't wait!

starflight

01-14-2008, 05:13 AM

From Adcom's FAQ I found the following...

There's a "thump" when I turn off my system.
There are usually two reasons for this: The amp has a large power supply and it doesn't use output relays. Let's look a bit more closely at both.

First, a power supply's job is to filter and store energy until the amplifier circuitry needs it. Adcom amps have HUGE power supplies. That's part of the reason they sound as good as they do. But when you turn the system off, that energy has to go somewhere. The "thump" you occasionally hear is the power supply capacitors dissipating the energy. It's not dangerous at all. In fact, it's just another sign that the amp won't run out of steam when you really want serious sounds.

Yes, we could have used output relays that would disconnect the speakers as soon as the amp turned off. That way, you would never hear the thump. But relays, as we've already seen, aren't great for real high fidelity sound quality. If we used them, you would never hear how good our circuitry is either. Is that a sensible tradeoff? We sure don't think so.

Look at it this way: The "thump" is the same thing as a high performance automobile's rumbling exhaust. The sound alone tells you there's something serious under the hood, right?

--------------------------------------

However, it would appear as this should happen only when I turn of the system but this thumping is happening each time I get no sound to sound which can happen alot when listening to CDs and movies or changing channels on the TV..hmmm....