The Kramer 907 is a Class D power amplifier for line-level stereo audio signals. It accepts a balanced stereo audio signal on a terminal block connector. It delivers 150 watts per channel of music output to the speakers. I was testing out this Kramer 907 tiny power amplifier the other day and what can I say, this bloody thing can really pump some serious wattage! The following is a description of the features:
• Input and output on terminal block connections
• A volume control knob
• Gain control DIP-switches
• A mute button
• 24V DC power
I must say that power amplifiers like these are really useful for small applications such as powering a pair of small, outdoor speakers at say, a client’s restaurant or maybe even some small front speakers in a board room. very useful and small and I bet it does not cost half the earth. I also like the fact that it uses Phoenix connectors, hence the small footprint.
My client had two of these QSC CX108V 70V amplifiers conk out on them and they were duly sent for repair. Apparently there was a problem with the “housekeeping card” or whatever that is. So those offending electronic items were duly replaced and sent back after repair.
I have always been interested in QSC amplifiers. I can never forget when I had a pair of QSC MX2000 amplifiers 25 years ago in the club, doing a damn good job f powering some Turbosound loudspeakers. So I was equally in awe about these 8-channel units and this is what I found out about them after looking them up o the web:
- 100 watts per channel at 70 volts
- Compact size—only two rack spaces and 14″ deep for reduced rack space
- Channel pairs bridgeable for maximum flexibility
- Exclusive PowerLight switch-mode power supply technology for high performance and compact size
- Active inrush limiting eliminates AC inrush current, removing the need for expensive power sequencers
- Four HD15 DataPort connectors (one per channel pair) for Q-SYS networked control and monitoring
- Custom integrated gain control security cover for tamper-proof installations
- 1-dB recessed detented gain controls for fast and accurate settings
- Detachable Euro-style input and output connectors
- DIP switch control for clip limiters, high-pass filters, bridge mono and parallel operation
- Selectable high-pass filters protect speakers and prevent speaker transformer saturation with minimal effect on program material (50 Hz or 75 Hz)
- Comprehensive front panel indicators including signal, clip, bridge mono and parallel input LEDs
- Fully protected—including DC, infrasonic and ultrasonic, thermal overload and short circuit protection
- High-performance Class AB+B complementary bipolar output circuitry
- Lightweight—only 21 pounds (9.5 kg) for easier racking and shipping
And lightweight is true indeed. Unlike QSC amplifiers of old, these seemed almost featherweight. After installing them, they did the job and sounded as great as ever. Gotta love these QSC amplifiers. They will be giving many more years of service with no more issues…I hope!
I have been planning to get a pair of new NEXO PS15-R2s but I was deciding whether or not to get this amp. The beautiful thing about this amp is that it has the power amplifier and controller all in one package. But this thing ain;t cheap. Some list prices I saw online price it at close to $5000! But then again, it is a darn sight cheaper than the Lab Gruppens whose equivalent to this amplifier would cost twice as much
On Yamaha’s web site (NEXO is a Yamaha subsidiary) for its commercial audio systems, I found some information about this amplifier, in fact, the whole NXAMP line. This is the smaller brother of the bigger NXAMP4X4. This is how Yamaha describes it:
NXAMP is the complete integration of newly-developed high capability DSP processor and state-of-the-art power amplifier technology. NXAMP has higher DSP capability than NX242 and is compatible with all NEXO speakers. NXAMP monitors power voltage and currency of amplifier outputs, drives the whole system safely and maximizes speaker capability. NXAMP also adopts “EEEngine”, a high-efficiency amplifier method by Yamaha, and produces Class AB sound quality with high efficiency comparable to Class D amplifiers. Furthermore, NXAMP boasts overwhelming stability and high reliability implementing an independent power supply unit for each channel (4 channels total).
Quite a mouthful eh? But looking at the NXAMP4X1, it is able to put out 1300 watts @ 2 ohms, 900 watts per channel into 4 ohms and 600 watts per channel into 8 ohms. There are 4 channels as mentioned previously so that is pretty hefty. But this thing is pretty light…only about 16 kilograms.
So if I want to get a pair of PS15-R2s, it is gonna cost me about $3000 per speaker, making it $6000, plus one NXAMP4X1, bringing it to $11,000 just for the sound system. Egads. That is some serious cash but then again, as it is said, you only let your wallet cry once and after that, all should be OK. So decisions have to be made…..
Everytime I see a karaoke setup and if there is a power amplifier like this installed, I know the owner is in good hands. The reason I think so is this. In 1994, I was contracted to install a karaoke room in a hotel in Batam Indonesia. In any case, the electrician that set up the place did not set it up properly wiring-wise and the whole place caught fire. Luckily the place was installed with water sprinklers and the next morning, we were told about the fire. We rushed to the hotel to check the damage. All the audio equipment was ruined…or so we thought. While clearing away the equipment, I saw that this amplifier was charred on the outside and the knobs and power switches were melted. I replaced the knobs, opened the unit and dried the components and cleaned it out and would you believe it, it fired up perfectly!
There are some who are thinking…yeah…maybe this amplifier did not bear the brunt of the fire but let me assure you, it did. Its feet were melted, so were the knobs. And the front panel was charred. Also, water from the extinguishers ended up in the unit. But after some TLC, it worked. Good on you BMB!
My friend sent me this pic of this unknown amplifier some time back, say about a couple of weeks back, asking me for the specifications of this amplifier. To be honest, I trawled the webs and I could not find any information about this brand at all, much less its specifications. It looks like BMB rip-off, like most China amps are. So if anyone has any information about this amplifier, kindly let me know please? Thanks
I was at a client’s place a few days back and I happened to notice for of these in their rack. Interesting, I thought. What manner of amplifier is this that I have only just heard about only today? I mean, I know about Samson’s other offerings but this is the first tome I came across this four-channel variety. This amplifier is a 2U, four-channel industrial power amplifier for distributed power applications. It is capable of delivering 120 watts RMS output per channel at 4 ohms or 80 watts per channel at 8 ohms, but can also run at 70 or 100 volts. Not too bad actually. Its a Class D amplifier too so looks like it will be pretty light but wait…this baby has a toroidal transformer so maybe it may be a slight bit heavier than most other Class D amps. This amp has been discontinued. A shame really. I know of some applications and installs where this amplifier would have come in useful
About a month back, while doing an event, I checked out what the hotel was using as an in-house sound-system. I could not see what speakers they were using but I did manage to get a glimpse of the amplifiers that they were using to power the speakers. This is the one…from a brand called C-Mark. I have seen their speakers in use before in a karaoke bar but this is the first time I had seen this amplifier and I must say that I was pretty impressed.
First of all, its a Class D amplifier so it was pretty small. According to their website, this GA500 model puts out 300 watts per channel into 8 ohms and 600 watts per channel into 4 ohms. That, by itself, is pretty impressive. Notice that I am talking about just one of these amplifier modules. But this is the shocker. It looks like there is only one Speakon connector at the back…an NL4 one at that. Probably that is what it does…using pins 1+ and 1- for the left and 2+ and 2- for the right, or vice-versa. There is a built-in power supply by the looks of it and each module weighs a hefty 3 kilograms.
These amplifiers look interesting. I would love to get one for an install I am doing…