Need Zu Definition Pro Subwoofer Array Amp for $1k

Hello everyone! I'd appreciate your guidance. I also sent an email to Adam at Zu to get his feedback.

I'm trying to match a stereo amp or pair of monoblocks (or dual mono amp) for my Zu Pro speakers passive woofer arrays. The front arrays are driven by a Yamamoto A-08S.

My other gear:
Canary CA-903 Line Stage Preamp
Ayre CX-7e CDP
Roksan Radius 5 TT w/Zyx Airy S cart.
Canary CA-400 Phono stage preamp
Rane PEQ55

My budget for the subwoofer amp is around $500-$1000, though I could stretch that a bit if an amazing deal surfaced. After spending a few days reading through MANY, MANY, MANY posts and on-line reviews, here are the options I'm considering:
Emotiva XPA-2
Nomad Niagra
Classe CA-100 or DR-9
Carver Silver 7t monoblocks (a SS copy of the Silver 7 tube monoblocks)
Odyssey Stratos
Belles 150A Hot Rod Version or 350A
McCormack DNA-1
Krell KAV250a or KST-100
Bryston 2B-SST or Bryston 4b Pro
Musical Fidelity Supercharger 550K - ok, this is out of my price range, but do I need this much power to control the woofer array?

One other consideration is I'd prefer, though not a requirement, that the amp accept XLR connections b/c I must pass the signal from my preamp through the Rane PEQ55 to the subwoofer amp. This will allow me to filter the signal below 40-65hz and below for the subwoofer array (the subwoofer drivers go down to 16hz and up to 1khz). The Rane PEQ55 has XLR connectors only and RCA/XLR cables are harder to come by on the used market (I prefer not to use cheater plugs), so an amp with XLR connectors would be a better option for me. Of course I can get around this with an XLR to RCA cable, but I'd prefer XLR to XLR.


PS I found a post on Agon about the Pro woofer arrays that was kind of helpful:
12-01-06: Miklorsmith
While the rear arrays of the Pro's seems easy, with their high efficiency, my experience has been anything but.

First, I had a Bel Canto 300, which should have plenty of output. It didn't. Sean at Zu told me to try a conventional Class A/B amp. I found an Adcom 555II, which has 200 wpc and should have been a champ. It wasn't.

I then tried an inexpensive NAD amp which fared no better. All these amps had the same problem of insufficient output and insufficient definition.

Then, I tried the amp circuit of a 60 wpc Audiolab amp - here we go, much better! Then, I went to the local stereo shop and traded the Adcom for an old Hafler 220 DH, with about 110 wpc. I'm sure it gets better, but this amp at $210 is the best I've had.

I'd call Sean and get his votes. Zu has certainly heard more Pro setups than anybody and can surely direct you well. Don't accept anything less than superlative bass. And, don't be afraid to cross over higher than 40 hz. Try 65 hz, which feels to me to blend very well with the fronts and provide some excellent midbass pop which is not possible with the front array.

INSERT FROM ME: The poster ultimately went with a Crown K2 amp which he swears by, though I'm not leaning toward the Crown amp because of the other options I listed above.
Well a few things… I owned the Crowns, and the Odysseys on this setup.. Forget the Odyssey, it is a very bad match, the high damping of the amp does not mate well with low exersion, high damped pro audio drivers at all. The crown is not half bad, good mix because you have to remember something "Impedance" is the killer matching your PRO Rane EQ to an amplifier, not only the impedance match but the fact do you really want to convert over from Balanced operation with the XLR to an RCA adaptor? Not recommended in my experience with these kinds of active setups. Also by the way the Odyssey is NOT a true balanced input on those amps, its just single ended with a ground jumper to the #1 and #3 pin, which are also wired OUT OF phase to the U.S. XLR balanced gear, so you would have to actually go into the amp and re-solder them to match the phase of the Ranes XLR.

Anyway forget all that because your not going that route anyway. I could Highly suggest the Mccormack DNA series for a good price, however I have not specifically heard it in this application, and once again you will lose the GAIN of at least 6 db due to they are not balanced power XLR, this also can increase distortion, and the IMPEDANCE of the Rane matching possibly… I think the DNA 1 is also a problem with its only 10k input impedance. Also that is the other issue of the Odyssey amps, they are VERY low impedance at like 10k ohms… that’s excessively low for a lot of preamps or processors to drive depending especially for low frequency alone, I learned that the hard way! Get an amp with 20k ohm or better input and true XLR balanced operation in my opinion… That’s why the crown in the end made most sense for the money, they are about 40 k XLR impedance, and have plenty of power, run quiet, and are very Rugged for this duty.

In the end however Zu's very own new Plate amps in the Zu DEF II's which of course now cost much more were the ultimate solution that beat all the PRO setups I went thru. Not that it was just the amps, but the full package setup has changed significantly including enclosure materials, split tunning internally etc… Eliminating all the issues with the pros.

So I hate to say it, but go to parts express and buy 2 of the better Subwoofer plate amps for 100 or 200 each, run them as mono blocks in their own wood enclosures if you wish, and you can even run them without the Rane unit for far less complications and use the EQ controls right on them.

Also these plates have way more than enough power, MAYBE Zu will sell you a pair of their new Hypex amps they use in the presence model currently with a standard input to run your Rane to them for control. But if you want pure pro capabilities its gonna take some serious work to get the Rane tuned in correctly and a good matching amp.
Good Luck

P.S. Don't just buy any old PRO audio amp either, get the CROWN K1 Or K2 as mentioned, they run cooler, and Have NO FAN! You will kick yourself buying a cheaper 200 dollar pro amp with a loud fan running all the time in it. Or try one from a local Guitar center at first at least and see what you think.
Finally I also believe running the Pro's with a crossover on the Rane at the 100 to 120 hz is better due to the mid bass much stronger even though its a large overlap to the front drivers... Only way to get the lower 40 hz to 80 hz sounding as good is a lot of room treatments, or the Split tunned Zu Def II models.

By the way if you do go with a better quality Audiophile style Single ended/RCA amp, I MIGHT have the custom XLR with Locking RCA's on them still I could send you for cheap. They are only about 2 feet long I think though, maybe they are 1 meter.. Also I had a pair made by Zu as well, but they are not there. All a XLR/RCA cable are is the center pin "Red, Hot" on the RCA goes to the #2 pin on the XLR, and the #3 and #1 pins on the XLR Are simply combined as one ground, which is just the single ground wire off your RCA jack.


You gave me a lot of EXCELLENT suggestions. If these were your speakers (I just bought them used and I really like them so I'm keeping them), what would you suggest in order? I can buy the Crown K2 on ebay, or the plate amps from parts express for less than buying one of the amps I listed. BTW, SHAME ON ME for dismissing the Crown. I should have been more open minded even though the Crown is a PRO amp. Stupid, stupid, stupid!

You mentioned ordering "better" plate amps from parts express. Which would you suggest?

Thanks again! This is why I love Agon and I'll pay money to sell my equipment here! The amount of experience on this forum never stops amazing me!!!!

Its a tuff one... If you were to get the plate amps from parts express I suggest the ones that I believe have the parametric eq right on them. Its just like a 5 band or something which is really all you need and simplifies much more vs. the Rane.. Also you could recover the cost if that works out just selling the Rane on Ebay for 400 or whatever and you are even! You would be shocked even on this line array of woofers that 100 watts or 400 watts is really not a huge difference. The quality bass and blending I found was simply running the right setup vs. worrying about power or "what the optimal EQ setting is" because these speakers will react well with less finicky integration and "Lost bass nodes" if you simply run them as if they were one integrated speaker, thats why I suggest as many have go ahead and not be afraid to run these up in the 100 hz plus range, these are not Subwoofers in a conventional sense like Movies are rated for THX etc... To run 80 hz and below. Yes Zu for years have even themselves suggested running them at 40 hz which is where they designed the fronts to cut off, but believe me the Re-enforcement of the backs running you more full range giving you the "Punch" up above 80 and 100 hz definitely will most likely serve most recordings much better.

Again you have some decisions to make as to how easy or complicated you want to make this. Also how much really to spend. I can tell you whether you run a 100 dollar plate amp or a 1000 dollar combo pro rig you can end up with better than expected results depending on the room. Only issue is the plates and making sure they can be mounted and kept cool, if they are A-B type, which A-B vs. the Class D amps do sometimes sound much more robust and natural fill type bass. I mean I would for now see if you want to go with the Rane or not.

Is your Preamp XLR true balanced? If not than you might want to go the Plate amp route and eliminate converting back and fourth. If it is True balanced, well than you can keep it clean and make it all Rack gear using the Rane on top of a good XLR pro amp, it does not have to be a crown, as a matter of fact the QSC amps are a little cheaper and probably even better for the application with 300 to 600 watt ranges, but be careful there are many models and some can come with pretty loud fans, although most are 2 speed models that will not be noticed most of the time at low setting, and the Zu's really are efficient so they won't draw them that much. However again efficiency is a real trick here, has nothing to do with how overdriven an amp can get from driving an in-efficient load or even the impedance on these speakers which stays pretty stable at basically 8 ohms, probably dipping down in the 4 or 5 ohm range, but simply low frequencys will sweat an amp much more.

Best amp possible, My opinion although I would never spend this much even used on this application, would be a Mcintosh like 352 or 300... One that is true balanced, and they have relatively low damping factors around 100 - 200. They would really sound organic, but you would end up dropping 2000 to 3000 on an amp and not worth it in this application, so find something comprable otherwise. There are many used XLR amps around, but in the Audio realm over here vs. PRO you have to be careful they are really XLR balanced, not just a dummy jack that is XLR on the back, and that they are a higher input impedance, like I said I would stay with amp inputs of 20k ohms(20,000) or higher. Don't worry about wattage, but worry about quality and current drive, a 50 watt Class A amp would probably drive these better than a Cheap 500 watt Class D, but your talking more money.

If you really want to try a killer amp, the Monarchy Mono blocks are really sweet class A amps, true balanced, No feedback, will Crush those 10" drivers, but maybe just for plenty of Dynamic peak power you would want their like 100 watt per channel plus versions. They are also 100,000 ohm inputs, can be driven passivley with no preamp. So I think they would be excellent. Used you can get a pair around 1000 bucks, even monarchy might be running deals right now, but they do run very hot as they are 100% class A power, but would have an iron grip and sound like pure finess on these. I own a pair of the SM 70's which are sweeter but only 70 watts, they would work fine too, but driven off a Rane really putting them to the test with all super low frequencies I don't know the results. Oh and my monarchys in true balanced XLR easily beat the bass levels out vs. my Old Crown K1.. But totally different setup and applications. Remember my claims are only on very high efficiency and well impedance matched systems..No doubt 400 watt crowns in some speaker applications will be a better bet and run cooler.
This looks like a really short sweet solution!

SC-1250 Subwoofer Amplifier $995.00

The Velodyne SC-1250 amplifier is a combination high-quality 1250W Class D amplifier, with built-in DSP room correction. Velodyne developed this amplifier for their home theater installer based network and their Contract Series subwoofers.
The amplifier section is more powerful than the 1250W rating would indicate. It is capable of significantly more power under transient conditions and it tends to be a fair amount more powerful than most 1000W plate amplifiers. The difference is noticeable with most of our high-output Exodus Subwoofers, giving additional headroom before the onset of clipping.

The DSP room measurement tool is the real kicker. While not as flexible as the SMS-1 solution, it does allow for an Auto-EQ room measurement & equalization. This is the perfect solution for someone who wants a high quality amp, and a no-nonsense set-up routine for any passive subwoofer.

High quality 1250W, 3000W burst amplifier.
High Pass 80Hz (6dB/octave) crossover for main speakers to help reduce distortion.
Low Pass Crossover 30-160Hz, 24dB/octave defeatable.
Inputs: Line and Speaker Level
Outputs: Two subwoofers (limited to 4 Ohm nominal load total), one line-level with 80Hz high pass filter.
Phase: 0°, 90°, 180°, 270°
Dimensions: 4 ¼" x 17.0" x 13.0"


Thank you so much again. I know that reading "thank you" messages may mean little, but I am VERY thankful for the time you put into answering my questions so clearly and thoroughly. Thank you!

My preamp (Canary CA-903) only has RCA outputs, which is the main reason I am shying away from using the Rane which only accepts XLR inputs.

I think the Velodyne SC-1250 is the right solution for me. I don't have any software to "dial in" the correct bass levels. The Velodyne SC-1250 includes a microphone to help me do the set up for my room which is ideal. In addition, the SC-1250 has RCA connections so I don't need a pair of RCA to XLR IC's which will help keep the costs down. BTW, the SC-1250 comes with a remote control which is a huge plus. Vanns is selling the Velodyne SC-1250 for $999 and they're including a pair of 8" Velodyne SC-8 subwoofers and shipping is free. I need one of these in our bedroom and I'm sure I can put the other to use somewhere :-)

The only concern I have is whether or not the Velodyne SC-1250 will support the signal down to 16hz which is the floor for the Zu woofers. Will it?

If so, I'll pick up this unit because it seems like the overall best solution. I know Velodyne makes very reputable subwoofers, so I expect the amp to sound really good.

Unless of course you have any other suggestions that are better than the Velodyne SC-1250. :-)

Thanks again,
I spoke with the sales rep at Vanns and the SC-1250 only goes down to 30hz. Seems there is a 24db loss for each octave below 30hz.

The Monarchy blocks look very good. They are running a 2 for 1 special right now, so a pair would be under $1179. A pair of SM-70's is on Agon for $1k. For $200 more I'll go with the SM-100 Delux Mk2 amps.

I have a call into C.C. Poon, CEO of Monarchy, to discuss the application and determine which amps are the best fit.

I found a less than favorable review done back in 2004 by hometheaterhifi written by Jason Victor Serinus. He wasn't very impressed by the amps, though his equipment budget is 10 times as high as mine. For example, he wrote:
This review must thus be placed in perspective. The Elrod EPS-3 power cables I plugged into the amplifiers list for $1100 each. My Elrod EPS Signature powercords that I use elsewhere in the system cost $1700 each. Contrast that to the price of the amps. It is doubtful that many audiophiles who own $16,000 speakers, a $10,000 DAC/preamp, over $20,000 worth of cabling, a custom transport, and a kaboodle of tweaks are likely to set their sites on these diminutive amps. The odds are that they’ll go for the bigger stuff.

It is equally questionable whether mating C.C.’s bargain products with such revealing components does them an ultimate service. More modestly priced components rarely offer consummate resolving power, and are generally more forgiving of amps built to a price point.

He liked the Monarchy Hyprbids.

Anyway, I think the amps have been upgraded since 2004 based on Monarchy's website.

I'll keep you posted.

Reviews and applications are never always in line...The SM 100 is not quiet as good for really critical Audiophile needs as the SM 70's are. Don't worry about it, trust me the Monarchys are capable of the best and for your application its even sillier as they are in fact only going to do low frequency anyway if you go with the 100's. I believe Monarchy will give you a trial run and you will be a charged a re-stock fee if they did not work out. Yes speak with C.C. Poon he will guide you. I know they would work rather well, but again you could go for something with a little more power and less heat no doubt.

That is strange on the Velodyn? I would almost try it if its possible and return, but that would be ABSOLUTELY silly if in fact Velodyn one of the Kings in subwoofers did not produce a unit that would play down to the standard 20 hz range capability... Hell the Monarchys even though the spec. does not say it I believe will drop in well under 10 hz!

By the way I am still on board for the Velodyn, I think it will produce the frequencies just fine, by the way you will have a nearly impossible time getting anything under the 'A on a steinway piano or whatever at 27 hz to play, the speaker and the room just will not probably do it, you will get some feeling, but thats all that occurs anyway. Even cutoff at 25 hz will play 99.9% of any Techno/ artificial Rap music with all the low end power and authority possible. Rock, Jazz don't get to hung up on specifics, go hear something and use something that works for you.

Too bad you just missed a 4 day old ad on one of these from audiogon, sold quick, it sold for 600 bucks or something, its retail is like 950, its a little more muster and goes very low apparently against the velodyn! However no remote, or digital mic correction... But I have heard they are pretty good. see links They are all different links, but not sure why when posted to audiogon they all look the same! Just go to each one.

Good Luck

In Full Range mode the Gallo amp is 10Hz-28Hz. In Low-Pass mode the amp is 20Hz-180Hz. How can I get it to go down to 10Hz and up to 100Hz that you recommended? I think it would be one or the other, but the specs listed at the bottom of this post seem like the amp supports from 10Hz-200Hz. I just don't know *how* to set it up so that it goes from 10Hz to 100Hz that you suggested.

Is the amps impedence ok? Is it equal to the input sensitivity of 130mV? These are technical areas that are beyond my understanding.

I found them for $675 new with free shipping, so if you think it would be better than the Velodyne or the Monarchy amps I could still get one...or two.

I would have to run the Rane EQ if I use the Monarchy amps which is fine as long as it is the best solution. I would need a pair of XLR to RCA IC's, and I think you mentioned you still have pair.

Basically, I'm open to any of the three solutions you suggested. I just want to make sure whatever solution I use will be the best. Everything else I bought in my system is the best I could afford, so getting the best amp for the woofer arrays is my goal. I know I have a budget restriction, but these are three excellent options. Which do you suggest?

I understand there isn't a lot of music under 20Hz, but I do listen to classical and there are some organ pieces that get down there. The ability for the Zu's to get down to 16Hz was one of the principle reasons for my buying them over Cains, so I want a solution that will utilize the full bandwidth of the Zu's.

BTW, the Veloydyne SC-1250 was specifically made for the Velodyne SC subwoofers, none of which dip below 22hz. I think that's the reason the SC-1250 doesn't go below 30hz without a big drop off.

The Gallo has a "low noise" fan which I can't understand unless it is a class A amp. I don't think I'd hear it even at low listening levels anyway, but it's odd that it has a fan. I hope it isn't always on though. There are no specs for the noise level of the fan which I find odd given the amp is for stereophile applications.

Here are the technical specs for the Gallo:
The frequency response of this amplifier is 20Hz - 180Hz (Low-pass) and 10Hz - 28Hz (full range). It has 240 watts (stereo) or 600 watts (bridged) output. The dimension lists 17/19″ (W) (rack ears removable) x 4″ (H) x 14″ (D). It has possessed a weight of 25lbs. The input sensitivity is 130mV. Phases acquired are dual mono and continuously variable phases.

Output Power: 2 x 160 watts RMS @ 8 ohms
20Hz - 20kHz (stereo mode)
2 x 250 watts RMS @ 4 ohms
20Hz - 20kHz (stereo mode)
450 watts RMS @ 8 ohms
20Hz - 20kHz (mono mode)
650 watts RMS @ 4 ohms
20Hz - 20kHz (mono mode)

Distortion: 0.08% stereo, 0.1% mono
(low-pass @ 100Hz, level and xover at max, EQ at 0dB)
.01% stereo, 0.17% mono
(full-range, level at max)

Input Sensitivity: 130mV stereo, 110mV mono

Signal-to-Noise: 93dB stereo, 83dB mono
(low pass @ 100Hz, level and xover at max, EQ at 0dB)
93 dB stereo, 75dB mono
(full-range full-rated power @ 1kHz)

Load Impedance: 2 ohms or greater in stereo mode /
4 ohms or greater in mono mode

Bass EQ: 1W @ 35Hz (100Hz=0dB, level and xover at max, booster at 6dB)=6.2dB
1W @ 35Hz (100Hz=0dB, level and xover at max, booster at -3dB)=-3.2dB

Frequency Response: 15-200Hz low-pass (100Hz=0dB, level and xover at max, booster at 0dB)
<10Hz - 28kHz full-range (100Hz=0dB, level and xover at max, booster at 0dB)

Crossover: 40Hz low-pass, xover setting at minimum
200Hz low-pass, xover setting at maximum

Power Handling: 250 watts @ 4 ohms
160watts @ 8 ohms (In Stereo)
650 watts @ 4 ohms
450 watts @ 8 ohms (Bridged to mono)

12 Volt Trigger: Tip = (+) Sleeve = (-)

Auto-on Sensitivity: 5mV

Current Draw: 9A stereo, 13.5A mono
(level and xover at max, booster at 0dB)

Protection Circuitry: Short circuit, open circuit, RF burnout, over temp., speaker protection relays, Turn on/off transient protection, DC protection, and limiter circuitry

Temp. Protect: 60°C +/-5

Cooling: A low noise fan is utilized to draw cool air through the chassis using front and rear vents. Do not block the vents.

Power Requirements: 100 VAC 60Hz, 850VA
100-120 VAC 50/60Hz, 850VA
220-240 VAC 50/60Hz, 850VA

Connections: RCA inputs, 5-way binding posts
I just noticed the amp is 10Hz-28Khz. So, that answers my question about the amp supporting the full range you suggested from 10Hz-100Hz.

I wish I could edit my last message!

Well even most amps rated to 20 hz will probably play 16 hz, you are going to have a hard time getting something to support the spec of actually "16hz" this has more to do with the fact the speaker is actually efficient and tunned to play that low, not really the amp spec. If the info is down that low with any kind of authority than it will pass, the amp and any amp that I would know of is definitely down probably 3 to 12 db anywhere around 20hz...

Now thinking back to a Zu rule, they automatically boosted their amps in the Definitions(the ones with built in amps) by actually adding 10 db of boost just in the 20hz alone setting. Almost anything playing on most recordings thru your speakers or anybodys will need a lot of help down that low, unless you have totally perfect room acoustics, with like built int 18 " free air subs built into your foundation or something to boost that much power at those frequencies, which you still might not hear from what I understand, but feel some of the air and vibration. I can tell you this, I have had some of the best speakers show me a spec of 30 hz and just under... They have had better bass due to the tunning was really capable of it.

Most speakers rated at even 20 hz which is obviously for the most part very high end ones that cost some money still in my opinion have difficulty proving or producing it in any kinda viable musical way that will make or break a system.

My suggestion again, Don't get caught up in that spec. even with the Velodyn I bet it will actually produce the signal lower than the 30 hz rating and even if it does will not be that noticeable, so yes honestly you will need about 12 to 20 db of bass boost in the 25, or 20, or 18 hz range to even hear it mostly! This will be hard to do without using pro gear like the rane totally cranked up to its max gain in those frequencies and an amp almost any will do it, but if you fed a signal that deep for any duration it would probably just putter out or overheat anyway in most cases, were talking most recordings will retain a 16 hz signal for about 1 second if your lucky, you will not miss much.

By the way vinyl for example has rumble filters many times on the phono amp to actually Kill off any of this noise at 25 hz and below! Mine can produce 20 hz even thru a speaker rated to be 30 hz.

This stuff is getting taken a little to far honestly, your problem and major wall to hit would be "So what if you did hit 16 hz" because you will probably NEVER produce it in your room, unless you have some money invested in testing the room acoustics, and probably even a lot more money in actually tuning your room to produce it. Pick a good setup for you, money, function, and overall will it sound good on your speaker? It will be fine with any of these amps, ultimately the choice will be whats best to fit your needs...

I will warn you worrying about the 16 hz spec will have you chasing the dragon. Again it was barely any difference with the 20 hz 10 db bass boost as most music never would produce it anyway, I don't care what the rating or specs are... Make sure you can hear and feel everything between about 40 hz and 120 hz and you will be knocking the walls down!

By the way those amps have some serious current draw it looks like... You will need for mono's at least 2 dedicated 15 amp power lines. 13.5 amp is not slouch thats about double any mono I have used, and a 15 amp circuit should really only be run up about 12 amps. Thats why many go with 20 amp breakers in this case. I would stick with Stereo versions or some kinda Class D efficient amps.
Wow, thank you for the explanation about lower frequencies! I had no idea. Learning something new every day!

Here is the feedback from CC Poon at Monarchy about an email I sent him inquiring about both of his amp. I used quite a bit of the information in your posts and described my application. Here is what he wrote:
Our SE-100 is a single-ended amp. The Hot and Cold Signals from the XLR are fed into the same input. (Hence "SE" )

The only True Balanced Amp we make is our SM-70 PRO, which uses two amps for a channel: one channel for Hot signal; the other amp for Cold signal.

Other than the architecture, the two amps are similar in size and price.

Both amps should met your needs for hum free, and good damping.

So, what do you think? Velodyne, Gallo or Monarchy? If Monarchy, which pair?

I don't have room treatments, though after I get all my equipment purchased, I will focus on that next.
Might I step in here with another budget suggestion?

A classic(or two) Hafler DH-500 amp run about $250-$350 ea. These 50 lb beasts are legendary for driving just about anything and are bridgeable to 800 watts into 8 ohms. They were mainstays in the Pro audio world for decades and thousands are still in use. There are also companies that do extensive(& expensive) mods to them.
Power Rating: Less than 0.025% total harmonic distortion at any power level up to 255watts continuous average power per channel into 8 ohms at any frequency between20 Hz and 20 kHz with both channels driven.

Frequency Response into 8 ohms:
-3 dB, 0.5 Hz to 120 kHz at 1 watt
+/-O.5 dB, 5 Hz to 40 kHz at 255 watts

Input Impedance: 47,000 ohms
Input Sensitivity: 2.35 volts for 255 watts into 8 ohms; 0.145 volts for 1 watt
Damping Factor: 200 to 1 kHz into 8 ohms; 60 to 10 kHz into 8 ohms
Rise Time: 10 kHz, 80 volts p/p square wave, 10% to 90%: 2.5 us.

"The over-sized power transformer, the conservative operating levels of the MOSFETs, the computer-grade electrolytics totalling 40,000 microfarads, the enclosed relay, the use of film capacitors in signal circuits-all are evidence of the design efforts to achieve exceptional reliability simultaneously with state of the art sonics and specifications. So rugged is the DH-500 that it can deliver over 20 amperes into a short circuit!"
Obviously, Undertow's experience with Zu's speaks for itself, he really knows his stuff. But the Haflers are worth considering for any subwoofer application. Do a web search on the DH-500's or the pro equivalent D-500, it has a long and illustrious history. I found the fan in the D-500 to be too loud for home applications, but DH-500 works well.
Hmm, that is interesting I was not aware the SM 70 was the only config with the true balanced XLR from monarchy. Not that its super critical as it will still work without an adaptor if you chose the SM 100's and a standard XLR cable will work just fine from the Rane to the amps.

Or as stated above by Darkmoebius, go with an older cheap amp that will do the job and hook it to the rane, or simply try a full on solution if you prefer to try and do this easier eliminating the extra EQ in the path, dumping the Rane....

I mean if you can get an amp or something local to just HOOK up to these speakers to try out would be your best bet just go to any guitar center, or sam ash, buy a decent pro amp make sure you have the 30 day return policy, and go hook this sucker up and have a little fun and knowledge!

At least this way you can get the Rane with a pair of cheap Mic/XLR cables going, by the way all you need is the HOSA brand type XLR cable sold at all your music shops for like 10 to 20 bucks a pair maybe radio shack. Then make a decision if the rane is going to work out for you and chose an amp based on if you want to keep the rane in the system or buy an all in one solution with some extra convienence factors on it like the Gallo or the Velodyn.

If you keep the rane then order a crown or something better if you feel thats how you will like to continue, my thing is learn the Rane system, and see how good of results you can get tweaked in which if its good and works well for you, and you love the sound than you found the answer.

Again these are all going to work for subwoofer control, don't get too caught up on specific attributes.

You did say your preamp is RCA only? Well if you don't want to mess with all this I can tell you whether you spend another 300 or 3000 your gonna be within 5% of what your going to get out of this system. So bottom line is if you want the simplest, most quality, effective purchase its probably going to be eliminating the Rane from the mix due to the conversions, the extra gear plugged in, and the extra dialing in needed. However you have it already, and it is the more expensive solution as it stands so add a 300 dollar pro amp and get to it!

Like I said take very little risk going to a local pro shop grab an amp, and a pair of XLRs, and for the second set of cables from preamp to rane either make them up using RCA jacks you can pick up at the local Radio shack to hack the ends off one side of the XLR, or get some cheap adaptors, which actually I believe radio shack or many guitar centers etc... do carry to convert your xlr to RCA.

Thank you for the direction. If I didn't sense getting kicked out of the nest on this one (possibly a case of paralysis through analysis) I'd ask if Crown or QSC is better.

But, realizing that I have to DO rather than ASK I'm going to get a couple of pro amps and start getting familiar with the Rane.

Adam from Zu also suggested three pro amps to use and the K2 was one of them (Threshold and MC2 were the other two).

Unfortunately, the K2 isn't available new any more, but it is available via ebay.

Time to do. I'll report back my findings. Thanks again for your patience and guidance. Audiogon needs to make gift giving via Agon credits possible.

One last question: can you email me with the price for your XLR to RCA cables? I'm at mark.kellman at gmail

Mark - I am also a Zu Def Pro veteran. The Crown K-2 is what I used for my bottom end ultimately after employing Pass and Bryston. Use a dbx Drive Rack PA instead of the Rane and don't worry about the quality of cables for low frequency. True balanced circuitry cancels noise and you needn't be too concerned below 60 Hz. anyway. I found that $15 mic cables from the music store worked quite well for low end.

There really isn't much to be missed below 50 Hz. on music programs. Home theater is where the bottom is most appreciated.
>>07-04-09: Macrojack
There really isn't much to be missed below 50 Hz. on music programs. Home theater is where the bottom is most appreciated.<<


Using Zu as an example, one need only hear Druid alongside Definition or Presence to know this is untrue. There's a lot of music to hear and feel under 40Hz.

Dealer disclaimer
Thanks guys for your feedback. I've been manually working with the Rane and I simply know that I'm not capable of dialing in the sound the way it should. Although I've been able to get it close on a number of occasions, the sound is not where I want it to be.

[B]So, I have a questions regarding the dbx DriveRack PA.[/B]

The Velodyne SC-1250 has a great function to press a button and the amp calibrates itself for the room. Does the dbx DriveRack PA offer similar functionality? I read a review and it sounded like that is what the writer intended.

If the dbx DriveRack PA doesn't have an AUTO EQ function that calibrates itself, what other solution is out there? Should I have someone come into my home with software and set it up, or should I buy another piece of equipment that would work like the Velodyne? Unfortunately, the Velodyne is engineered for their SC series of subwoofers which only go down to 22Hz. The Zu Pro's go down to 16Hz, so I want a solution that will help me calibrate everything that needs to be calibrated because I don't have "Golden Ears".

BTW, I bought the Behringer EP2500 based o reviews and significant bench testing done by another forum's member. It is a FANTASTIC amp for the money. In fact, it rivals many of the amps at 2-3 times the price. I simply need to replace the fan b/c the fan used is for pro conditions and I'm using the amp for home use. There's a lot of information, pics, and detailed steps to replace the fan. I already found the fan, so it's a matter of installing it. The noise level will drop from about 45db with the existing fan to under 19db with the new fan. Owners who replaced the fan cannot hear from their listening positions and NO ONE has had a problem running the amp with the replacement fan even in HT applications. A $10 fix and about 30 minutes of time. Not bad!

Thanks again,
I used the Drive rack PA... This was my solution over the Rane simply due to cost, and ease of saving the settings in the drive rack opposed to going back and forth on the rane dials.

I don't know if its the answer, the Rane should be virtually as good in theory, but there is a few more toys on the DBX.

There is a standard EQ. and you can change the "Q"? etc... To really work it into a more accurate range I guess, but its hard to say whether its gonna be a perfect solution or not. It has its major learning curves as well, it is a bit complex and navigating the menu of it and saving settings etc... Will take some time and changes. I have not had anything with that for over 2 years myself so I don't even remember where I finally ended up. However cost vs. the Rane to performance I can't say first hand. It did take about 3 months of experimenting and tons of different types of music to do this by ear, measuring might help, but I don't have much suggestion on that.

Good Luck
I use a Drive Rack PA too. When I had my Def Pros I used a Rane. I think the dbx is far more versatile and easier to use. There is a huge learning curve but it offers near universal control for only about $400 from Amazon. I bought the dbx matching microphone along with it for another $90 or so. This allows for RTA room correction which the Drive Rack does for you.

In my experience nothing touches it for this kind of money. It is a serious professional sound control device. And fun to play with, as well.
I spoke with Zu awhile back and they were not very enthused about the dbx auto-EQ feature.

I am not familiar with the PA model but if you buy a dbx product that is supported by their DriveWare software (model 260), you can run a serial cable to an USB/Serial adaptor and configure from you listening seat. You can use graphic EQ, parametric EQ and notch filters (extreme parametric EQ) all in the same configuration. You can apply gain boost if needed. You can see a graphical representation of these, choose among crossover types, etc.

For converting RCA to XLR, there are transformer-based units available from Jensen and others that should work better then simple adaptors.

You could use mild EQ along the crossover rolloff curve to compensate for an overdamped bass amp.

There is a free program SynRTA available from Liberty Instuments that will allow your to see you room response in real time as you make adjustments with DriveWare. Resolution is up to 1/48th octave.

Also you can use a program like XTZ (easier to use than Bare) to identify parametric EQ and notch filter settings.

One track I use for setup is Line Dancing With Monkeys off of Jeff Beck's 'Jeff' cd. It will let you know if you have any bass issues.