Class D amp technology translates to lots of power in a lightweight package
By Craig Anderton
Senior Editor, Harmony Central
Peavey's been doing Class D (digital) amps since the DECA series debuted about 30 years ago (I still have my DECA 700, and it still works). The IPR series is the latest incarnation of this technology; the IPR 1600 being reviewed is the lowest-powered of the line, with the IPR 6000 being the most powerful.
When the box arrived, I almost wondered if they forgot to pack the amp—I'm still not quite used to a seven-pound power amp. Documentation is on an included CD-ROM; the paper documentation is a "safety instructions" boilerplate, so check out the electronic manual before powering up.
When you plug in, the power switch and Peavey logo light up, making it easy to tell whether power is available. Switch on power and you get a light show—blue LEDs inside the unit provide an inviting glow. The fan on the back is variable-speed, so the harder the amp works, the faster it spins; at high loads you can hear the fan, but under those conditions you're likely pumping out a lot of volume, so the relatively low fan noise is pretty much moot.
Ins and outs
The two inputs use balanced combination connectors that accept either XLR or 1/4" connectors. You can use unbalanced inputs, but of course, balanced is preferred. Each channel also has a thru/out pass-through jack if you want to feed additional power amps, a recording setup, etc. The outputs have 4-pole twist-lock connectors. These can accommodate 1/4" connectors, but twist-lock types are far more reliable—use them instead of 1/4" plugs.
Channel mode functions
Thanks to a 100Hz Linkwitz-Riley crossover filter, the IPR series amps are subwoofer-friendly, as controlled by the three-position Channel Mode slide switch that determines the channel's frequency range. With the switch in the High Pass position, frequencies above 100Hz pass through the channel for driving midrange and high-frequency drivers. The Full Range position applies no filtering, which is ideal for lower-power applications where a subwoofer is not necessary. Finally, the Subwoofer position passes only frequencies below 100Hz. As there are two channels, you can use the IPR 1600 as a mono amp with one channel feeding the subwoofer and the other feeding the remaining speakers. In this situation, a full stereo setup would require two IPR 1600 amps.
As expected, there are also front-panel input level attenuators. Although I always start off with these at minimum, the IPR 1600 does have volume ramp-up circuitry so that turning the unit on doesn't produce output "thumps."
Practicing safe amp
The IPR 1600 includes five LEDs for each channel to monitor signal and the status of the various protective circuits. Individual LEDs indicate active and signal present. Another LED monitors the DDT (Distortion Detection Technique), which indicates if the amp is at the onset of clipping (flashing on transients), or enabling protection (lit steadily, which controls the amount of distortion going to the output). Another LED indicates thermal overload, and remains lit until temperatures return to a safe level. The final LED indicates abnormal conditions (e.g., DC output). If this LED lights, presumably, the amp shuts down, although this didn't light during the course of testing.
The biggest plus for many people (other than chiropractors!) will be the weight. After years of carrying around amps that could serve as boat anchors, this latest implementation of Class D technology is a game-changer—you can carry it under one arm. Put a bunch of these in a rack, and you'll probably still be able to carry the rack around without needing someone to help.
The main caution is ventilation. The IPR 1600 runs cooler than you might expect and the light weight may fool you into thinking it's not working all that hard, but it is. There needs to be good ventilation on the sides, front, and back (for the fan), so keep this in mind when you set it up. Also, remember to read the documentation so you understand what the protection LEDs are trying to tell you, and make sure the Mode switches are set to their correct positions.
I was able to drive speakers to major volume without any issues, but do make sure you're not tripping the DDT clipping protection—occasional clipping is not an issue, as the DDT takes care of that, but sustained clipping means you really need more power for the task at hand.
Overall, the IPR 1600 is pretty boring—and that's a good thing: Set it up, make your connections, turn up the volume, and forget about it while it does its thing. The sound is clean, the bass is particularly punchy and tight, and the crossover is effective. Top that off with a very attractive price, and you start to understand the considerable advantages of Peavey's latest generation of power amp technology.
Features & Specs
- • 800W/channel into 2 ohms, 530W/channel into 4 ohms
- • 100Hz crossovers for each channel
- • Multiple speaker and amplifier protection circuits
- • Class D amplifier topology
- • Variable-speed fan adjusts as needed
- • Extremely light weight—7.125 pounds (without power cable)
- • Combination XLR/1/4" input jacks
Get serious power without breaking your budget—or your back—with this lightweight, versatile stereo power amplifier. Order today with the complete assurance of Musician's Friend's 45-Day Total Satisfaction and Lowest Price Guarantees.