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Discussion Starter #1 (Edited)
When I upgraded my theater room to an Atmos setup, I blew most of my budget on the pre-amp (Yamaha CX-A5100) and speakers (DIYSG 1099's + Volt surrounds & Atmos). I didn't want to spend another several thousand dollars on a new 11ch amp at the moment, so I went on the hunt for a high quality budget-priced amp to drive the system temporarily. What I ended up buying turned out to be such a great amp that I decided to keep it for good! And I got it at an absolutely ridiculous price - just $180 delivered!! That was an unusual deal, it looks like you can currently get one for around $350-$450 delivered, which is still an incredible value for what you're getting. Or if you're patient you can wait for a good deal like mine to pop up on eBay. Hell, just last month one lucky person scored one with a winning bid of just $0.99 w/free local pickup! :eek:

The amp I'm talking about is the Crestron CNAMPX-16X60. This is a 16 channel amp made by ATI which was designed for Crestron whole-house audio systems, but it can very much be used in a home theater setup as I'll explain below. This amp was by designed legendary amplifier engineer Morris Kessler, and it was the first ever 16 channel amp to deliver 60W/ch. It uses the exact same amplifier boards and transformers as several other other high-end amps made by ATI - such as the ATI AT2007 (MSRP $3,000), the Crestron CNAMPX-7x200 (MSRP $5,000), and the current bang-for-your buck champ the Monoprice 7x200 (MSRP $1,500). The only difference with those amps is they have 7 two-channel boards which are internally bridged to produce 7 output channels (one channel driving the + and the other channel driving the -), while this amp has 8 two-channel boards with 2 output channels = 16 channels. But, one little known fact about this amp is that ALL channels are bridgeable externally (more on that below), giving you 8 channels of output @ 220W!

The specs on this one-of-a-kind beast are VERY impressive:

Output Power (20Hz-20kHz, all channels driven): 60Wx16 @ 8 ohms, 90Wx16 @ 4 ohms, 220Wx8 bridged @ 8 ohms (NOT 4 ohm stable on bridged channels)
Power Bandwidth: 3Hz to 50kHz, +0/-3dB
Frequency Response: 20Hz to 20kHz, +0/-0.1dB
Total Harmonic Distortion (THD): ≤0.03% at full power
IHF I.M. Distortion: ≤0.01%
SMPTE I.M. Distortion: ≤0.03%
Dynamic Headroom: ≥2dB
S/N Ratio: >110dB A-weighted
Gain: 28dB
Damping Factor: >400
Channel Separation: >100dB, 20Hz to 20kHz

BUILD QUALITY:
The phrase "built like a tank" almost doesn't do this amp justice. It weighs nearly 100lbs, has 8 individual amplifier boards - each with their own power supply and held together with dual-braces along the tops to keep everything in place, the amp heatsinks are MASSIVE, as are the two soft-start toroidal transformers, the boards are all glass epoxy coated for protection against the elements (such as humidity, dust), and the speaker terminals are mounted directly to the chassis - rather than being mounted to a board inside the chassis - so you can use the heaviest gauge wire known to man and still not see any terminal sag! I actually tore the whole thing apart and inspected every inch of it out of curiosity, and to clean all the dust out of it, and I was blown away by the quality throughout. I'll post some pics in a reply below.

ATMOS SETUP:
As shown in the specs above, the output of this amp is 60W @ 8Ohms in single channel mode, but when you bridge two channels it jumps up to 220W @ 8 Ohms. And all 16 channels (8 amp boards) are bridgeable, despite the Crestron manual saying you should only bridge channels 1-4 and 13-16. I'm guessing that is recommended to prevent any chance of overheating, but it's obviously possible to run them all bridged without a problem since the AT2007 and Monoprice 7X200 both have 7 of the same boards running bridged with no overheating issues. And that, my friends, is what makes this such a great Atmos amp: by bridging 10 of the 16 channels you are able to get 5 channels @ 220W (for the L/C/R/SL/SR), with the other other 6 channels @ 60W (for the RSL, RSR, and 4 ceiling Atmos). At first I thought the rear surrounds and Atmos speakers might get overpowered by the mains getting 160W more power, but then I realized they probably don't need as much power since they are located about 8ft closer to my ears. I used an SPL calculator and determined that with my fronts getting 220W @ 16ft and the others getting 60W @ ~8-10ft, the SPL at the listening level will be almost exactly the same! (108.7dB for mains, 109dB for surrounds & Atmos).

GETTING THE AMP UP AND RUNNING:
The first question many people have about this amp - and this is probably what scares a lot of people away from using it for home theater use - is how to run it without being connected to a Crestron system. It's actually VERY simple. All you need to do is provide 24V power to the Crestnet port via an external power adapter. You can use any old laptop charger or wall wart that puts out 24V with at least 1A. First you cut off the plug end, then take the green 4-pin terminal that goes to the Crestnet port and connect the positive (center wire) to the top post marked 24V, and then the negative (outer wire) goes to the bottom port marked G. If your amp didn't come with the green phoenix connector you can buy one on eBay for a few bucks. Once you plug that in you'll see a green light come on indicating that the Crestnet card is getting power, then you just hit the red bypass button and the Crestnet card inside will be bypassed allowing you to use it like a regular amp. Once you've done that you can power the amp on & off via the front switch or a switching power conditioner, but you MUST leave that 24V on at all times. If the 24V ever loses power you'll need to hit the bypass button again when power is restored. I plugged mine into the "always on" outlet on my power conditioner so I'll never need to hit that red bypass button again. It only uses 12W of power to run the Crestnet board so we're talking maybe $1/mo to leave that power on 24/7.

BRIDGING THE AMP:
One very important thing that I figured out with this amp is you DO NOT NEED the special Crestron CNXBRMO bridging module listed in the user manual to bridge this amp! All you need to do is provide two out-of-phase RCA signals to each channel, which can be done nothing nothing more than a $5 XLR/RCA y-cable if your pre-amp has XLR outputs. But even if it doesn't, you still don't need the hard-to-find Crestron bridging module, there is a much easier and cheaper option.

If you DO have XLR outputs, all you need is 5 female XLR-to-dual RCA y-cables. I bought these on eBay for a total of $16 delivered, but they're a tight fit at just 1.5ft long. If your amp and receiver are further away, I found these 1.5m (3ft) cables for just a few bucks more. All you do to bridge the channels is plug the XLR end into your pre-amp, connect the two RCA ends to two channels on the same amp (i.e. 1&2,3&4, etc), and then connect the + speaker wire to the + of the top channel, and the - speaker wire to the + of the bottom channel, and you're now getting 220W over a bridged connection!

Now if you DO NOT have XLR outputs on your pre-amp, then you will need one additional thing - a Henry Matchbox device. They can be bought on eBay for around $30-$40 delivered, sometimes even cheaper if you can find a multi-pack (I once saw a 5-pack sell for just $50!). Each unit will provide 2 XLR outputs which will give you 2 bridged channels, so you'll need 3 of those boxes to get the 5 bridged channels that you need. The way it works with those boxes is you use the RCA output of your receiver, connected to the RCA input of the Matchbox, the use the above-mentioned XLR-to-RCA splitter cable from the output of that box to the back of the Crestron amp. Then connect the speakers to both + terminals as described above. Using this method adds another $100-$120 to the cost of the setup, but you should still be able to keep it under $500.

CONCLUSION:
So there you have it - an audiophile-grade 11ch Atmos amp on a budget! With the cables (and the Matchbox units if necessary) you're looking at somewhere in the range of $300-$500 total, depending on what kind of deal you get on the amp. That is a ridiculous bargain compared to something like the 11ch Yamaha MX-A5000 amp which costs $2,500 and only puts out 150W/ch to the mains (8 ohms, 2ch driven), and nowhere NEAR that much with all channels driven since the amp maxes out at 650W (and that's total power consumption, not output power, so with a 75% efficiency of a Class G amp you're talking more like 455W which is just 41W x 11 with all channels driven!). Or if you go the Monoprice 7x200 route you would get 7 channels at 200W rather than just 5, but then you still need to power the additional 4 channels which would cost another couple hundred for a good quality 4ch amp, so you'd be close to $2,000 for that setup. This is less than 1/4 the price for basically the same exact amp, and it's an all-in-one solution.

I ended up being so impressed with this amp that I actually just bought another one, and I'm going to bridge 5 channels on the first amp and 6 channels on the other for all 11 channels @ 220W with all channels driven. Probably completely unnecessary, but I scored an equally ridiculous deal on the second one at just $165 delivered. So my 2,400W 11ch amp setup will end up costing a whopping $380 out the door....and I'll still have 10 channels left over, which I'm going to use to power my whole-house speaker system that I'm getting ready to install. :)
 

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Discussion Starter #3
Giving credit where due, I got the idea from THIS POST. But I figured out a way to make it work without any internal modifications needed to the amp so it remains 100% stock.
 

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Discussion Starter #4
Here are some pics of the internals, before taking it apart and cleaning it up. The very last pic shows the two wires that need to be connected to the NET port on the back to be able to bypass the Crestnet board and use it like a regular amp.

I can post some teardown pics too if anyone is interested.
 

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A couple things to keep in mind for the Crestron CNAMPX-16X60..
1. Basic build quality from ATI is quite high
2. Double check Craig's list and/or e-bagger for availability as used ones are selling for
 

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Discussion Starter #7 (Edited)
5. Replacement batteries are available but expensive
What battery? I tore mine down to the chassis, only thing I didn't remove is the transformers, and I didn't see a battery anywhere. So the only place it could be is hidden behind/under the transformers. What would be the purpose of a battery, if there is one?

I did some Googling and the only mention I found of a battery for the 16x60 is for the wireless Crestron remote control, which obviously isn't used unless you actually have a Crestron system.
 

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What battery? I tore mine down to the chassis, only thing I didn't remove is the transformers, and I didn't see a battery anywhere. So the only place it could be is hidden behind/under the transformers. What would be the purpose of a battery, if there is one?

I did some Googling and the only mention I found of a battery for the 16x60 is for the wireless Crestron remote control, which obviously isn't used unless you actually have a Crestron system.
The majority of Crestron amplifiers were used for complete Crestron multi-zone systems included the amplifier and a wireless control panel, battery was memory backup power of the control panel. Also as posted previously, depending upon the manufacture date if >10 years old check the power supply electrolytic capacitors they tend to leak and short out. And when they short they take out certain other components, 1st warning sign is an audible fixed hum level.


Just my $0.02... ;)
 

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Discussion Starter #9 (Edited)
**UPDATE: I decided to leave this board in because I found out that it handles all of the amp protection, and it shuts off the power if there is ever an overload or short which could damage the amp. With that board removed you could easily kill your amp by simply touching the + and - speaker wires together**

One small modification that I'm doing to the amp is when I put everything back together I'm going to leave the Crestnet board out, along with all of the unnecessary wiring harnesses that are connected to it. That board serves no purpose if you're not using the amp with a Crestron system. And then I'm going to install this 12V->24V step-up converter which will allow me to use a 12V incoming single to supply the 24V for the main power relay and the output board relays. I'm going to drill a small hole and put a 12V outlet on the back of it as well.

This is the board that will come out, along with all of the wires connected to it.

 

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I just puked up a 12x60 for my surround channels. Thanks to gmanhdtv’s pics on his other thread, the power wiring switch was easy, 20 minutes, tops. Before I hefted the beast into the rack, though, I plugged it and powered it on to make sure it would, and it did power on, but the light in the power switch is flickering. I’ll open it back up and do the basic checks for power tomorrow night, but just wanted to check in and see if anyone more experienced could point me to likely sources of the flickering....just a dodgy switch?
 

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I just puked up a 12x60 for my surround channels. Thanks to gmanhdtv’s pics on his other thread, the power wiring switch was easy, 20 minutes, tops. Before I hefted the beast into the rack, though, I plugged it and powered it on to make sure it would, and it did power on, but the light in the power switch is flickering. I’ll open it back up and do the basic checks for power tomorrow night, but just wanted to check in and see if anyone more experienced could point me to likely sources of the flickering....just a dodgy switch?

The flickering is due to the fact a neon bulb is used. Same switch that was also used in the Acurus 200x3 first generation amp's. The bulb's are available on Ebay, switch is easy to take apart if you are careful and then change out the lamp. I have rebuilt 4 total the switches are no longer for sale. ATI also used the same rocker switch in some of their older designs as well.

Good Luck!
 

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Discussion Starter #12 (Edited)
An update on my project - I have since modified the 2nd one that I got off eBay, and I now have my 11 channels split between the two amps - the whole right side (5 channels) on one, and the whole left side + center (6 channels) on the other. So I'm bridging 10 of the 16 channels on one amp to provide 5 output channels, and 12 channels on the other amp for 6 output channels. And I removed all of the extra boards that aren't being used to increase airflow inside the unit for better cooling, so I have a leftover stack of 5 amp boards - which I'm probably going to sell on eBay to recoup some costs. So now all 11 channels are getting 220W @ 8 ohms, for a total price of just $380! :)

Also, in the meantime I picked up another 16x60 amp on my local Craigslist for just $100! Guy had it listed at $200 and said he doesn't think it works b/c he can't get it to turn on. I offered him $100, he said sure. Took it home and it works just fine when 24V is applied to the Crestnet card! :p I'm going to use that one for my 8-zone whole-house audio system.
 

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Discussion Starter #13 (Edited)
One other thing I did is took out the output board and removed all of the 24V relays on the board. Those are used by the Crestron system to allow the Crestnet card to turn the channels on/off individually, but they serve no purpose when not being used with a Crestron system. And on one of the amps one of those relays was bad which caused one of the channels to not turn on, so I figured I'd eliminate that possible point failure and take them all out. I just replaced them with a small piece of wire to complete the circuit from the amp board output to the speaker terminal. It was kind of a PITA doing all of that de-soldering, but the entire project only took maybe an hour per board.

Oh, and I also completely bypassed the 24V power-on relay so now the amp just turns on & off via the front switch. I thought about swapping the 24V relay for a 12V and installed a 3.5mm jack on the back to conenct it to my receiver, but I'm going to have them plugged into a switching power conditioner so I don't need any 12V or 24V trigger control. If you want to go that route though, it just takes a $15 replacement relay on Amazon and a $4 3.5mm jack, so about $20 total to convert it to 12V triggered.
 

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I saw this thread and thought this would be a great idea for my system. I found 3 of these amps on a great deal so I figured I could use one (or possibly two) and then sell the extra/s. I see the posts where people bridge 5 of the channels and then just use the others as normal. Has anybody actually tried to bridge it to 8 channels to get the full 220 watts out of each one?
 

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Awesome information. Thanks to all for sharing your experiences. Just got one of the 16x60 units and am trying to bridge using several Henry Matchbox HDs. I have DIYSoundgroup 1099s as my L/C/R, concentric 8 surrounds, axiom qs8 heights for 5.1.2. I am hoping to add additional channels for atmos. I am using a Yamaha RX-A3070 receiver as preamp. I was able to power on the unit using a $8 wall wart to supply 24V to the amp combined with a $2 phoenix connector.

I have a 2 Belkin PF60 power conditioners I use to switch on multiple amps and everything seems to be working ok except the Crestron/Matchbox additions have caused hum issues. For some reason, I am getting a relatively loud hum when 2 channels are connected to the same Matchbox HD unit. If I run one channel per Matchbox the loud hum goes away. I'll have to check and see if it's related to the Belkin unit.

Also, there is relatively minor hiss/hum coming from the speakers (inaudible from listening position) connected to the amp - is that typical? When the 1099s are connected straight to the receiver, there is no noise whatsoever. It's my first time connecting 1099s to external amp.

My impressions thus far could be placebo effect as suggested by some other threads on this forum with external amps and sensitive DIYSG speakers like the 1099s - it sounds like a significant improvement to my ears after Yamaha's YPAO calibration.
 

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Also, when I put everything back together I'm planning to leave the Crestnet board out along with all of the unnecessary wiring harnesses that are connected to it. And in its place I'm going to install a 110VAC>24VDC power converter to supply the 24V which is needed for the main power relay as well as the output board relays. This will allow the amp to function like a normal amp without any sort of external power supply needed. I'll tap into the 110V coming in from the power plug, then the converter 24V output will connect to both the main power relay as well as pins 1 & 2 on the output board to trigger the 24V output relays.

This is the board that will come out, along with all of the wires connected to it.

Do you have any pics of the finished modification of adding in that power converter?
 

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Would somebody be able to direct me to an appropriate 24V laptop charger or wall plug that I could cut to make work with this amp?
 

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Awesome information. Thanks to all for sharing your experiences. Just got one of the 16x60 units and am trying to bridge using several Henry Matchbox HDs. I have DIYSoundgroup 1099s as my L/C/R, concentric 8 surrounds, axiom qs8 heights for 5.1.2. I am hoping to add additional channels for atmos. I am using a Yamaha RX-A3070 receiver as preamp. I was able to power on the unit using a $8 wall wart to supply 24V to the amp combined with a $2 phoenix connector.

I have a 2 Belkin PF60 power conditioners I use to switch on multiple amps and everything seems to be working ok except the Crestron/Matchbox additions have caused hum issues. For some reason, I am getting a relatively loud hum when 2 channels are connected to the same Matchbox HD unit. If I run one channel per Matchbox the loud hum goes away. I'll have to check and see if it's related to the Belkin unit.

Also, there is relatively minor hiss/hum coming from the speakers (inaudible from listening position) connected to the amp - is that typical? When the 1099s are connected straight to the receiver, there is no noise whatsoever. It's my first time connecting 1099s to external amp.

My impressions thus far could be placebo effect as suggested by some other threads on this forum with external amps and sensitive DIYSG speakers like the 1099s - it sounds like a significant improvement to my ears after Yamaha's YPAO calibration.
Did you ever figure out a solution to this? I'm pretty close to getting my amps going. Probably going to go the Matchbox route. They're pretty expensive right now though. Especially the new HD ones.
 

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Awesome information. Thanks to all for sharing your experiences. Just got one of the 16x60 units and am trying to bridge using several Henry Matchbox HDs. I have DIYSoundgroup 1099s as my L/C/R, concentric 8 surrounds, axiom qs8 heights for 5.1.2. I am hoping to add additional channels for atmos. I am using a Yamaha RX-A3070 receiver as preamp. I was able to power on the unit using a $8 wall wart to supply 24V to the amp combined with a $2 phoenix connector.

I have a 2 Belkin PF60 power conditioners I use to switch on multiple amps and everything seems to be working ok except the Crestron/Matchbox additions have caused hum issues. For some reason, I am getting a relatively loud hum when 2 channels are connected to the same Matchbox HD unit. If I run one channel per Matchbox the loud hum goes away. I'll have to check and see if it's related to the Belkin unit.

Also, there is relatively minor hiss/hum coming from the speakers (inaudible from listening position) connected to the amp - is that typical? When the 1099s are connected straight to the receiver, there is no noise whatsoever. It's my first time connecting 1099s to external amp.

My impressions thus far could be placebo effect as suggested by some other threads on this forum with external amps and sensitive DIYSG speakers like the 1099s - it sounds like a significant improvement to my ears after Yamaha's YPAO calibration.
Did you figure out what was causing the hum? I'm getting a little bit of noise through my fronts. Haven't done a done of troubleshooting yet.
 
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