Sunday, April 15, 2012

Old School 1990's 50 Watt Cheater Amps Tested

This post will be a work in progress until I complete my round of tests on the 25x2 Watt "cheater amps" from the 90's. I'll include a spreadsheet showing the results and links to the videos I create for each amplifier. Thus far, the test will include:

1) Rockford Fosgate Punch 45HD - from approx. 1991, not a true high-current amp like many of the other's, but well known to be underrated and able to handle almost any speaker load

2) Orion 225 HCCA - from the early 90's, test will include the "Digital Reference" and maybe the "Competition Amp/X-over" models. One of the most feared cheater amps of the early through mid 90's.

3) Precision Power ProMOS 25 - also an early 90's cheater amp rated to handle 1 ohm loads and promises the warm, smooth SQ of an early PPI amp

4) Phoenix Gold MPS-2240 - part of Phoenix Gold's "Mobile Professional Series" the MPS-2240 is identical in size to the MS-275 and is a high-current amp rated at 24x2 and designed to handle loads down to 1 ohm

5) Phoenix Gold M25 - the "M" series from Phoenix Gold were known for superb SQ and are very popular among collectors and those building old school systems as well.

6) US Amps 50HCA - an early version of a 25x2 cheater from US Amps. No crossovers, no terminal strips, just raw power and old school flair

7) US Amps USA-50 - a late 90's 25x2 amp designed to handle loads down to 1 ohm

8) Zapco Z50C2 - mid-90's amp, small in footprint, big in SQ

Bookmark this page as it will be continually updated with more information on each of these amps!


Tuesday, April 3, 2012

Some Really Powerful Mini Amps? The Rockford Fosgate Punch Boosted Rail Amplifiers PBR300x1 PBR300x2 PBR300x4

Rockford Fosgate Punch "Boosted Rail Amps" - From left to right; PBR300x1, PBR300x2 and PBR300x4

I get questioned all the time as to why I do tests and reviews of new amps on Isn't this website for stereo gear from the 80's and 90's? Well, yes, but I also like to test new products that stand out from the rest. As you may have seen on my YouTube channel, I like to make portable boomboxes and tiny amps such as the Rockford Fosgate PBR series intrigue me. Also, let me make it clear...these Punch PBR series amps pack a big power "punch" and are not to be confused with the other Chinese Mini Amps I've tested in the past. Those amps from Lepai, Kinter and others will brag about "500 Watts" or more and must have misplaced the decimal point when converting from Chinese to English or something...

The Rockford PBR series I'm talking about here are the 300 watt versions; Specifically the monoblock PBR300x1, stereo PBR300x2 and four-channel PBR300x4. Each amp is identical in size, but vastly different in output configuration.

  • The Punch PBR300x1 is a mono block amp, designed for subwoofer duty only. It is rated at 75x1 at 4 ohms, 150x1 at 2 ohms and 300x1 at 1 ohm. The PBR300x1 is also unique in that it relies on the three 15,000uf 25V caps to keep the rail boosted during high power operation. The PBR300x1 has no switching power supply toroid, whereas both the PBR300x2 and PBR300x4 do
  • The Punch PBR300x2 is the most flexible amp in this series as it is suitable for stereo, mono or tri-mode operation and has built in low-pass and high-pass crossovers. The PBR300x2 is rated at 100x2 at 4 ohms, 150x2 at 2 ohms or 300x1 at 4 ohms bridged mono. Before I purchased the amp, I contacted Rockford Fosgate to find out if the amp could be used in "tri-mode" operation (stereo and mono simultaneously) and the answer was yes. This intrigued me as it would allow me to test the amp using an old school tri-mode crossover, and possibly a good candidate for a boombox project.
  • Lastly, the Punch PBR300x4 is a four channel model rated only to handle 4 ohm loads at 75x4. You can choose Low Pass, High Pass or bypass for crossover duties. Unfortunately, no Punch Bass port is provided and the PBR300x4 is not bridgeable. This amp seems well suited for powering front and rear full range speakers.
  • All of the PBR300 series measure  6-15/16"W x 1-9/16"H x 4-5/16"D
  • Street price for the PBR300 series is around $250 US each
Not mentioned above is the recently introduced Punch PBR500x1. The 500x1 is not only larger in size, but also much larger in power output delivering 500 watts at 1 ohm. We may get one of these amps soon to run through the test bench, so stay tuned.

PBR300 series internal components, left to right; PBR300x1, PBR300x2 & PBR300x4

Over the past few months, we've had a chance to put two of the PBR300 amps on the OldSchoolStereo test bench and also run through some real world tests with speakers and subwoofers.

First to test was the original "Boosted Rail" amp offered by Rockford Fosgate, the PBR300x1. After seeing Steve Meade's video about this amp at the 2011 Consumer Electronics Show, I was eager to get my hands on one. PASNATION also has an excellent video explaining the technology in these amps. I also created a couple of videos showing off the PBR300x1. See them below:

Part 1: Unboxing and Overview - See on YouTube in 1080P HD or embedded below

Part 2: RMS Power Output Test - See on YouTube in 1080P HD or embedded below

After the apparent success of the PBR300x1, Rockford expanded the line of "boosted rail" amps with the PBR300x4 and most recently the PBR300x2. I purchased both amps, most recently the PBR300x2. With this amp's ability to work in stereo, mono, or both (using passive crossovers), I decided this might be the perfect amp for a high powered portable boombox. Also, to add some flair of old school, I decided to test the amp using a Phoenix Gold XVR4 tri-mode crossover network. The XVR4 provides 80Hz low-pass filtering at 12dB/octave and 120Hz high-pass at 6dB/octave. I thought this would be a perfect match for my recently created Rockford Fosgate AUDIOphile Bookshelf Speakers and a trio of old school JL Audio 8W6 subwoofers. It turned out to be a great combination indeed! See the full test and demo below:

Rockford Fosgate PBR300x2 Bench Tested and Demo'd - on YouTube in 1080P HD or embedded below

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