Amplifier for NVS Addictions

I see a pair of Addictions on my tower in the near future, and I'm trying to get some input on the amp of choice to power them. I've heard anywhere from 250-400 watts per side is ideal. I'm looking into the followings amps (all output in 4 ohms):

Arc Audio 4150-XXK - 320 watts x 2
DLS Ultimate A4 - 250 watts x 2
Kicker SX700.4 - 350 watts x 2
Hifonics Zeus ZX6406 - 340 watts x 2
Diamond D6600.4 - 300 watts x 2
Zapco 750.2NVS - 275 watts x 2
Rockford T8004 - 200 watts x 2
Memphis MCA3004 - 230 watts x 2
PPI DCX600.4 - 300 watts x 2

Any input on your current setup is appreciated.

Ryan,
Wow, that's a nice list! I don't have the time to get the specs on all of those but if you do would you fax them to me? (408-723-1609)
I'm hesitant to mention this but some are actually running a full 500 RMS on these guys...myself included. But even my partner Todd will tell you that if you don't take the time to set that kind of power up proper, poop will happen.
But if you think you know what you're doing, trow the Zapco 1000.4 in the mix.

Duane, thanks for the response. I can try and put together the specs for each amp and get them to you. I was just doing some research online and compiled a quick list. I've only had experience first had with a few of these companies, but have heard good things about each. Do you have a preference running 2 channels at 4 ohm or mono at 2 ohms. I see on your website you recommend both the Zapco 500.1 and 750.2 for a pair. 1000.4 might be fun as well.

Ryan,
Since the voice coils in the Addiction are actually rated at 250, we did all of our prelim work at this level. This turned out to be a very conservative approach as we started getting feedback from installing dealers that would provid a little more and note an improvement in performance.
So, Good is the Zapco 500.1, (parralel at 2 ohms) Better is the Zapco 750.2-NVS. This however is not just a power thing. As I think you know, many other paramters will make 1 amp perform better then another. The one paramter that I think doesn't get enough consideration is the damping factor. Control over a driver at these power levels is critical IMO, not just THD or Sig/Noise.
I am currently running a 1000.4 on a pair of Addictions. Another 1000.4 (technically only half of it) is powering an Entity 1010 as well. As supply becomes available I'll be switching to a pair of the Tyrants.....and maybe an Entity

"The one paramter that I think doesn't get enough consideration is the damping factor. Control over a driver at these power levels is critical IMO"

Duane, can you explain this more?

Adam, very good q.
Rather then use my interpretation, I found a nice explanation from Crown. It's a bit long but good.

UNDERSTANDING DAMPING FACTOR
Loudspeakers have a mind of their own. You send them a signal and they add their own twist to it. They keep on vibrating after the signal has stopped, due to inertia. That's called "ringing" or "time smearing."
In other words, the speaker produces sound waves that are not part of the original signal.
Suppose the incoming signal is a "tight" kick drum with a short attack and decay in its signal envelope.
When the kick-drum signal stops, the speaker continues to vibrate. The cone bounces back and forth in its suspension. So that nice snappy kick drum turns into a boomy throb.
Fortunately, a power amplifier can exert control over the loudspeaker and prevent ringing. Damping is the ability of a power amplifier to control loudspeaker motion. It's measured in Damping Factor, which is load impedance divided by amplifier output impedance. Let's explain.
If the speaker impedance is 8 ohms, and the amplifier output impedance is 0.01 ohms, the damping factor is 800. That's a simplification. Since the speaker impedance and amplifier output impedance vary with frequency, so does the damping factor. Also, the impedance of the speaker cable affects damping. Thick cables (with low AWG) allow more damping than thin cables with (high AWG).
The lower the amplifier's output impedance, the higher the damping factor, and the tighter the sound is. A damping factor of 1000 or greater is considered high. High damping factor equals tight bass.
How It Works
How does an amplifier control speaker motion? When the loudspeaker cone vibrates, it acts like a microphone, generating a signal from its voice coil. This signal generated by the speaker is called back EMF (back Electro Motive Force). It travels through the speaker cable back into the amplifier output, then returns to the speaker. Since back EMF is in opposite polarity with the speaker's motion, back EMF impedes or damps the speaker's ringing.
The smaller the amp's output impedance, the greater is the effect of back EMF on the speaker's motion. A amplifier with low output impedance does not impede the back EMF, so the back EMF drives the loudspeaker with a relatively strong signal that works against the speaker's motion. When the speaker cone moves out, the back EMF pulls the speaker in, and vice versa.
In short, the loudspeaker damps itself through the amplifier output circuitry. The lower the impedance of that output circuitry, the more the back EMF can control the speaker's ringing.
To prove it to yourself, take a woofer that is not connected to anything. Put your ear next to the cone and tap on it. You might hear a low-pitched "bongggg" if the speaker itself is poorly damped. Now short the speaker terminals and tap again. You should hear a tighter thump.
Damping factor varies with frequency. As you might suspect, damping factor is most important at low frequencies, say 10 Hz to 400 Hz.

ryan have you considered Soundstream ? I just recently purchased a SS VGA 1600 and the thing is a monster. Im running it @ 2ohms 800rms x 2ch. It was recommended by a friend who is a heavy audiophile and I couldnt be more pleased. There hard to find but I got mine off fleabay new for $350. Msrp I think was $900

KG, I've heard nothing but good things about the Van Gogh series that Soundstream used to make. If I was buying used Soundstream and PPI would be heavily considered. From what I've gathered in my research is their new line of amps aren't up to par with the competition.

I agree with you the new SS are not up to speed with the VGA series but my friend that recommended the VGA to me just bought the 1600 last week "new" off fleabay for $350. There out there if you keep your eyes open but few and far between. Good luck ! You have a nice list of amps and any should fit the bill which ever way you go.

What is the story of running an amp at different Ohm ratings? Does it depend on the speaker that you are using to determin wheather you are running 4 or 2 Ohms from your Amp?

depoint,
Be careful with the interpretation of the damping factor description post. It only describes the relationships. You still need to match your amp with the speaker impedance.

Depoint-It depends on how you wire the speakers and wether or not the amp is rated stable at that load. An amp running 2ohms will draw more power and run hotter then at 4ohms but the speakers will see much more power

I understand the damping post. Good read by the way.

So if I understand it right it doesn't matter how you want to hook up the amp at 2 or 4 ohms you are pretty much a slave to what the speakers are set at?

depoint, you are corect . maybe this will help. The resistance (ohm load) is dictated by the speakers and how they are wired

Depoint, you're a slave to what your speakers impedance are in a sense. For example lets say you have an amp that is 1 ohm stable. It's specs will look something like this 250 watts x 1 at 4 ohms, 500 watts x 1 at 2 ohms, and 1000 watts x 1 at 1 ohm. If you are wiring a single voice coil 4 ohm subwoofer your amp will be running at 4 ohm as well. If you run two of the same subs in parallel your amp will be running at 2 ohm and giving out 250 watts to each speaker. Like KG said, the amp will run hotter at 2 ohms. From what I've gathered the benefits of running a low impedance is added power from the amp. The negatives to this is your Thermal Distortion increases and decreases your control over the speaker (see damping article above). Most people see the benefits outweighing the negatives in subwoofer installations and run their amps at 1-2 ohms. However with loudspeakers such as NVS tower speakers, clarity and speaker "tightness" are important, which is why you see people running the amps at 2-4 ohms for this installation.

Depoint -Actually you have it opposite. The ohm impedance is dependant on how you wire your speakers or sub(s). Once the speakers are wired the amp then sees the impedance automatically.

Ryan thanks that helps alot.

Did you mean running two speakers in series? Or are you sending two speaker wires from each of the 1X terminals on the amp to the two speakers?

Depoint, in parallel. I had two JL 10W7s wired to a JL 1000.1. It seems like more and more 1 channel subwoofer amps are wired internally to accept two subs in parallel and have two positive and two negative speaker terminals.

Got it. Did not know about haveing the output for two speakers on a one channel amp.

So for a pair of NVS Addictions you could have a 500.1 amp and hook up both speakers and be golden?

I ran a Hifonics ZX6400 last summer(2x340). It overheated and shut off a few times when I was really leaning on it. Next summer I will be running a PPI 4125, unfortunately they are pretty much gone. Zapco has always made good stuff but it's not in everybody's budget.

Mike are you running fans on your amps? Ive added additional fans to all my amps as they do get driven way harder then if they were in a car and the one in the enclosed space in front of the co-pilots seat wouldnt last long without them.

Ryan,
I notice that most of the amps listed are 4 ch. Why. The last set I did I put a 2500 XXK Arc. Sounded awesome.

Mikeski,you will be really happy with the PPI 4125 but like you said,good luck finding one.I ran my 1010's and the Amp never gets warm,much less hot.I found that my JL 1000 get hotter then the PPI.

Chris, most manufacturers don't make a 2 channel amp that runs 250+ watts at 4 ohms. I listed the Arc 4150-XXK because it produces more power when bridged than the 2500-XXK and costs less. One question though, is there any issues regarding sound quality when comparing a 2 channel amp to a 4 channel amp bridged to 2 channels? Assuming both put out the same power per channel, and are running at 4 ohms will a difference be noted? I guess that's two questions. This is one of the areas where I haven't really learned the difference.

There is also Audiobahn. They make a couple of 2-channel amps amps pushing 300 watts stereo at 4 Ohms. The High current A2300HCT and the Mosfet model A3201T. I've got a A2300HCT pushing my NVS addictions and they sound great. The A3201T is a little smaller and I would have gone that route but they had none in stock and I got the same price on the A2300HCT.

I'll agree with BigEd.......I'm running my 808s with a PPI4125 and they scream. The specs in the book show that at a 4ohm MONO load I'm pushing 500x2 to the 808s.

Highly recommend this amp if you can find one.

http://cgi.ebay.com/Precision-Power-PCX-4125-Amplifier-4-X-100-watts-NEW_W0QQitemZ5860710631QQcategoryZ4950QQssPageName ZWDVWQQrdZ1QQcmdZViewItem

Adam,that is strange b/c my PPI in the specs says it produces 125RMS per channel(4)not 100RMS.



I always thought that 4125 meant the 1st # 4 is the # of channels and the 125 following was the RMS output for each of the channels.
4x125=500RMS @4ohms.....bridge it and you get 1000RMS @ 2 ohm....this is what my manual says about the PPI 4125....the one on e-bay is a little different.(looks the same)maybe it's a misprint?

A little confused as well. Zack, you have 500 x 2 at 4 ohms... how is this bridged?

Ed - I thought it was 125 @ 4 ohms, will have to look at the manual tonight.



(Message edited by coorslight on February 03, 2006)

Ed, I think it was a misprint too.
From what I can tell looking at it that is the 4125. And the price reflects it.

I'll throw my 2 cents out there on the 4125 (while I don't push my 1010's with it) I've heard it on someones and didn't think they sounded any better and definately not any louder than mine....I have no idea what the gain was set at or what the amp was crossed over at. I've been pushing mine with an audiobahn amp for a little over a year now and for the price it's very hard to beat and overheating is not an issue with it even in the 100 degree plus summer days.


Has duane or anyone ever tested db's and judged sound quality with differnt amps?


(Message edited by acurtis_ttu on February 03, 2006)

(Message edited by acurtis_ttu on February 03, 2006)

Ken.......the manual I'm looking at shows the following:

PCX4125
4x125 (4ohm stereo)
4x250 (2ohm stereo)
2x500 (4ohm mono)

I've put up a picture showing my 4125 setup.....channels 1&2 and 3&4 are bridged with each running 1 808.

Guys, nice find on that PPI 4125, and it appears brand new the guy just sold a 2400 from same project car which makes sense. Anyways what would be a good price to pay on that amp if I were to bid. I bet a pair of addictions would scream with that setup.

Nevermind, answered my own question using the search function. It appears a ton of people are pushing NVS with a 4125, and all bought new on Ebay for around $400.

And by the way found the old thread about Ryan "X-Star" when he was looking for info on the NVS. His name is now "Blue Malibu" hmmmm...

right on ryan, lake entiat and roosevelt!

wenatchee boy born and raised

roosevelt is the best. we houseboat there every year in august. nothing beats it and i look forward to it more than anything. take care-

Nice I grew up in Cashmere. Heading back to Wenatchee to watch the Super Bowl with friends. My parents have a cabin at Seven Bays on Roosevelt, nothing like beach camping, waking up to sunshine and butter as far as the eye can see. I'm living by Lake Sammamish right now. Boat should be all setup and out of storage in March for some riding, I'll add you to my contacts, I'm always looking for riders on both sides of the mountains.

lucky duck. we gas up and stuff at seven bays, but usually launch at keller ferry because that's where the houseboats usually depart from. we try to get them let us take off from seven bays, but they'll only do it if they have a boat up there. what a beautiful place. seems to be getting busier and and busier every year though. which is a bummer imo. i'd like to buy a place over there, it's just so far we're afraid we wouldn't use it enough. sorry to hijack your thread, just had to say hello. i'll leave ya with this. look familiar?! --later

Haha White Face Rock. My dad always kills it fishing for Trout directly across from there. If you're looking to buy, now's the time. Even if you don't use it enough, you can sit on it as an investment. Property value is only going up over there. Too nice of a place not to.

Eastern Washington thread hijack, how cool. My son and I spend a week on Omak lake every August at Stampede time. We are usually the only boat on the lake. I have some friends who live there, and we have a blast. I grew up there, so I also sport home field advantage.

By the way...my Addictions are powered by 2 (one for each speaker) JL Audio 300/1s. I just installed them, but I haven't got to hear them yet, as I am ironing out other issues with my winter project stereo install.


Oh yeah...my system
MB Quart NRA 450 head unit with wired remote
6 sets of the new 7.7" components by JL
1 - 13W7 Sub
Addictions
JL Audio 1000/1 Amp for the Sub
JL Audio 450/4 for the components
2 JL Audio 300/1 for the Addictions
2 Blue tops for the stereo
1 Blue top starting battery
(Yeah, it really rocks)

Never heard of a JL 300/1? The only 300s I thought they had were the 300/2 and 300/4.