New amp is making me grin from ear to ear =) - Page 15

Hey spacecowboy. I got the fans not so much for the movies as I did for SACD/DVD-A multichannel. Very demanding on a system. And I like it loud. Still may be overkill, but the thermal circuit will engage and let us both know.

BTW, Your siggy from Kirk is a classic! I still remember that scene. One I will always remember

BTW, I'm listening right now to a Carver ZR1000 and I'm very impressed. I have a NHT Evolution system which is not very efficient (86db) and a 59TXi powering them. The difference is startling.

James

Comparing the Crown XLS-402 with the QSC RMX-850: Some thoughts and questions . . .
In doing some searching, I noticed that the QSC amps have a variable speed fan. Anyone had a chance to compare noise levels between the two? If I was going for a full 7.1 system with pro amps, I'd hate to have to change out all the fans, but I don't play my system very loud; variable speed fans might be just the ticket. My equipment is in a closet 10 feet away from my listening position in the theater behind solid wooden folding doors; my HTPC fans aren't audible above the projector fan, but 4-8 amp fans going full tilt might make a racket -- I'm not sure.
The Crown amp does claima little more power (260w vs. 200wpc), though most of the other statistics seem pretty similar. Curiously, the QSC amps are heavier (35 vs. 25 lbs) -- better construction, or just a fluke??? Also, Crowns vent air front to back, while QSC vents back to front -- not a factor for me, but might be important to others. QSC has one fan, Crown two, so maybe the QSC one has to work harder/run faster??? Also, of course, the QSC amp runs about $50 more (ballpark).
Anyone had any experience in comparing sound of the tow amps side by side? Those of us trying to decide would be most interested in people's opinions on this.

One last thing -- QSC RMX 850 has "on-off muting," though the instruction manual says to turn down the gain all the way before turning it on, so I think those of us seeking a easy on/off solution (i.e. no knob turning) are out of luck. I'd love it if these amps had 12v triggers and soft start technology, but that's not the feature set people look for in pro amps at this price level, I guess. It's OK by me to have to turn all the amps on manually, but it's one more thing to scare my wife away from using the theater. I try to get her on board as much as possible, since it's her engineer salary, not my teaching salary, that paid for my equipment!!!


Bart K.

newbie question
am I going to need two cables ( RCA male to XLR Male ) since there are two inputs. 1 Input per channel.

Yes, that is correct. If you have a Pro Audio shop near you, they may have them in stock. If not the are a number of cable mfg. on the net that will be glad to make you some. I got mine from AVCables.com

Terry

After auto-setup on my Denon 3805, I am having problems with getting a descent sound out of my mains. During auto setup, the testing tone was also significantly lower or quieter on the mains compared with rest of the speakers. I have my mains hooked up to the XLS 402 crown pro-amp. (they are connected by two rca male to XLR male cables) The center and surrounds are way more overpowering than the mains in my 5.1 setup. When I go 2.1 for radio, I feel like I am hearing speakers from the 60's.
Any suggestions, I am getting frustrated.

Need to check your gain levels on the 402, and your receiver. Possible cause for what you have described is that the gain (the two little knobs on the front of the 402 for left and right channel control) is all the way down. Or that your receiver is setting gain levels for the front left and right channels too low.
I am running mine at 50% or half way to full on the 402.
Terry

I'm not familiar at all with the 3805, but is it possible that auto set-up does not affect pre-outs?

If the gain knobs are turned up, can you bypass autoset-up to ensure amp is functioning correctly?I doubt it wouldn't be..

brickie

Good point, I would believe the pre-out on the 3805 would have a fixed voltage output. I would turn the gain levels on the 402 up to the sound level I wanted, and then run auto setup and have the 3805 set the other channels to match. Just a thought.

I have my gain levels on the 402 half way up, and I re-tested it. I gave me an error message unlike the first time. However, the test tone was and still significantly lower

should I try testing it without the amp

How do I find out what my receiver's gain levels are, may I can turn those up...for my fronts only. I turned the amps all the way up, and it was still lower in volume when testing

Your menu should have a section for speaker calibration or trim adjustment. You should be able to see what your fronts are set at in relation to the center and rears. After reading Terrax's post I question my initial suggestion that auto set-up does not affect pre-outs. If that was the case then you would be required to make all trim adjustments at the amp and not the receiver. Highly impractical to say the least. I'd try hooking your fronts back up to the receiver and see what happens.

Ok, after re-calibrating the speakers, the test-tone to the mic on the fronts was close to as loud as the rest of the speakers. I did this by disconnecting the amp, and connecting it to the 3805. However, they still sound diluted, like they have no bass coming from them. It is a 4-ohm speaker, but that amp should be able to push these Phase Tech 9.1 mains. Any other suggestions

You don't have a 2nd receiver handy that you could try it with,do you?At least this way we could eliminate that the amp itself is bad.

brickie

Try using a different set of pre-outs, like for the rears or something. If you get the same results I doubt it's the receiver. Do those RCA to XLR cables have the proper pinout?

Jim

Try re-setting the micro-processor on the receiver and start all over again.

Jim

OK, I tried resarting the processor, and I am still getting the same results. The testing tone is louder when hooked up to the receiver compared to the amp. The front sound is coming all from the tweeter and nothing from the drivers. Realizing this, I tried hooking them up differently. There are four speaker terminals on each main speaker,. ( two on top, two on bottom) I have tried both. I was told the bottom one were for Bi-amping or Bi-wiring. If I hav'nt told you this yet, My mains are Phease Techs 9.1 towers. This is very frustrating, I have been working on these fronts for 6 hours now.

Stupid question, but there is a jumper between the two sets of posts right? If there was no jumper then you'd be amping only the highs or the lows, or kind of half bi-amping.........if that makes any sense. That would be a very good reason why you had no low end.

Bill , you have solved my stupid a$$ problem I have been dealing with all day long, and it had to to do with connector plates being connected to two terminals not being used. God I am an idiot. Thank you very much!!!!
By the way! It sounds great!!!!

Excellent! I'm somewhat surprised that the jumper was not hooked up. I'm assuming that these speakers are brand new as well? While many people do bi-amp their mains, I've never heard of speakers set up initially for it. It's typically something the user sets up, not the factory. Either way, glad to hear that it's all up and running. Enjoy!

My rt3000p's are setup the same way, so glad you got it going.

brickie

Ok guys, I'm asking for your opinions here. I mentioned before that I wanted to get two more 402's and run them bridged. I'm rethinking that now, and have my decision narrowed down to two choices.

The Crown XLS602a or the QSC RMX2450. The RMX2450 is more powerful, but the XLS602a is a little cheaper. I am however prepared to spring for the QSC.

Either of these amps would be powering a set of Polk RTi 150's, which are rated to handle 500 watts. The 150's are being used in HT/2 channel duty.

What I'm asking I guess is, which would you buy, and why?

QSC: http://www.qscaudio.com/products/amps/rmx/rmx.htm

Crown: http://www.crownaudio.com/amp_htm/xlsspec.htm

Terry

In this scenario, I'd stick witht the Crown!If it's been good why change?Either way you're going to send those speakers WAY MORE power than what they're rated for!So unless this is a test to see which amp could possibly blow them up the fastest,I'd stick with Crown.Price factor and the performance that I've witnessed so far.

brickie

either amp will do a great job for you!

both companies have excellent track records and great warranties.....

cheers!

I run the rti150s as mains in my system. I originally ran them w/ my PE 53tx, then upgraded to a Crest CPX1500 (300 w. channel), and am now running them w/ a Crest CPA900 (600 w/channel.)

The 300 watter would clip into the 150s with DVD-A music at or near reference.

With the CPA900, no such problems. The additional headroom of the 600 watter is VERY noticable at low volume settings as well.

The 150s are phenominal spkrs. The more power the better they sound.
Buy the most powerful amp your budget allows.

Whether its QSC, Crown or Crest, go for more watts. I buy Crest 'cause a bud gets me great deals.

You have the potential to send more power to the speakers, but that
doesn't mean you will... that is why the volume knob was invented

If you already bought Crown amps and want to add more, but now
you may want to buy QSC, that is fine too.. But to keep the cosmetics
the same, it looks nice to use the same brand so you can show off.

The Crown I have is in my computer room powering some Maggie MGIIb's. My RTi150's are in the living room with my HT set-up. So the matching is not a problem. Also, I would venture to say that the 150's would handle a 1000 watts without problem, as long as I didnt get carried away with the level, hehe. I'm leaning toward the QSC, for a couple of reasons, one, more power, two, haven't heard them yet and a few others. But, really wanted to see what you guys thought.

Terry