Sunday, October 16, 2011

Amps that Rumble...Earthquake PA-2040c and PA-2300

Earthquake PA-2040c and PA-2300 Amplifiers from 1995. Photo (c)

One of the "sleeper" Car Audio brands back in the mid-90's was Earthquake. Competing against established brands such as Rockford Fosgate, Orion, Precision Power, Soundstream, etc. proved to be a difficult task. Everyone had a favorite brand, but how did the lesser known brands survive? Well, building quality products was one way and another was to test well in the Car Audio magazines. Earthquake accomplished both of these tasks and although never became as popular as the brands listed above, they did create a place for themselves in old school car audio history!

I recently acquired two Earthquake amplifiers and will briefly overview them below.

First up is the Earthquake PA-2040c. The PA-2040c is a two-channel amplifier with a built-in crossover. The crossover is non-adjustable and either 80Hz low-pass or 200Hz high-pass at 12dB/octave. You could also bypass the crossover to use the amp full range. In addition, the amp also included rotary bass and treble controls at 45Hz and 12kHz. Going by the model number, one might assume the amp is rated at 40w x 2, however specs in the included manual state 52w x 2 @ 4 ohms. I'm still unsure of the "250 watts at 2 ohms" silk-screened on the amp. I don't see any specs referring to this power at 2 ohms? Maybe Earthquake was following lesser brands with "max" output claims? Well, only the bench test for RMS output power will tell us....

Earthquake PA-2040c Amplifier Controls

Earthquake PA-2040c Amplifier Top View

Earthquake PA-2040c Amplifier Speaker Outputs and Power Connections

Earthquake also produced larger amplifiers, such as the PA-2300. Again, going by the model number, one might assume 2 x 300 watts, right? According to the manual, 2 x 380 watts RMS at 4 ohms and a mind-boggling 1150 watts RMS at 4 ohms bridged. In the mid-90's there were few car audio amplifiers claiming 1000 watts plus. The PA-2300 had no internal crossover, but had a counterpart, the PA-2300c, which did. A rather unusual feature of the PA-2300 was the dual bass controls. One centered at 30Hz and the other at 45Hz. Why two bass controls? I'm not certain, but maybe a tuning choice for those using sealed vs. ported subwoofer enclosures?

Earthquake PA-2300 Amplifier

Earthquake PA-2300 Bass Controls and Inputs

Although these amplifiers look very similar to amps made by Zed Audio (HiFonics VII, VII, Autotek BTS series, Crunch CR series, etc.), Earthquake amps were NOT made by Zed Audio. Although this is the case, rest assured the Earthquake PA series amps were built like a tank. The amps you see above were originally purchased in 1995 and variants of the PA series went back to the early 1990's.

Stay tuned for upcoming power output tests of these amps. Make sure to SUBSCRIBE to my YouTube Channel to stay notified of my latest video uploads.

See the mystery "unboxing" of these Old School Gems below:

Video in 720p HD

or embedded below:


Sunday, October 9, 2011

Orion 275 SX - Old School 75x2 Powerhouse!

Old School Early to Mid-1990's 75x2 (150 watt) RMS Amps from Rockford, Phoenix Gold, Soundstream and Orion

So, you may have already seen some of my earlier amp output tests on the Rockford Fosgate Punch 150HD vs. Phoenix Gold MS-275 and the Soundstream Reference 300....but what about the Orion 275 SX? Well, wait no longer, my friends. I finally got the Orion 275 SX on the test bench for some RMS watt output tests. How do you think it compared to the others? Well, keep reading to find out.

Now, first of all, I think it is important to mention a comparison of the 275 many ways, it is very similar to the 225 HCCA. Both share the same sized heatsink and require a 35A fuse. I've done some preliminary tests with Orion's 225 HCCA "digital reference" amp a while back and I must say the amp was VERY impressive! The 275 SX is only rated to handle 4 ohm mono or 2 ohm stereo loads. As with many of the old school amps, it can handle lower ohm loads, but not designed to handle the 1/2 ohm loads as the 225 HCCA does without a sweat!

Orion 275 SX vs. 225 HCCA vs. Messy Test Bench!

Instead of spending so much time comparing the 275 SX to the 225 HCCA, let's move on to the comparison against the other 150 watt amps I've mentioned before. Here are the specs of the 275 SX:

Specs: rated @ 12.5 volts*
2 x 75W @ 4 ohms
2 x 150W @ 2 ohms
1 x 300W @ 4 ohms bridged
THD: 0.03%
S/N: 110dB
Freq. Response: 6Hz 20kHz (±0.5dB)
Fuse: 35A
Dimensions: 11" x 8.5" x 2.25" (28cm x 21.6cm x 5.7cm)

*note: The Orion 275 SX uses an unregulated power supply, so more volts = more power! Also, my power supply is non-adjustable at 13.8v, nearly a volt and a half more than Orion's 12.5v rating, so take this into consideration.

Orion's 2nd Gen HCCA and SX Spec Sheet / Manual

Ok, enough specs and talk about the amp, let's see how it performed.

Watch the video in 1080p HD

or embedded below:



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Sunday, October 2, 2011

Soundstream Reference 300 Power Output Test

Soundstream Reference 300 on the Test Bench

I recall back in the early 90's patiently awaiting my monthly Car Audio magazines so I could see amp tests. It was very rare to come across a test I actually cared about, but maybe once a year or so. I drooled over the Phoenix Gold MS series, Rockford Fosgate HD series, Soundstream Reference series, just to mention a few. Well, these days, I spend some of my free time bench testing some of these amps I always wanted back in the day.

I recently picked up a Soundstream Reference 300 and couldn't wait to add it to my old school 150 watt (75x2 RMS) amp tests. If you've missed it, I've already done an overview and RMS watt output test of the Phoenix Gold MS-275 and Rockford Fosgate Punch 150HD.

The Reference 300 is a no-frills old school amp. It has no internal crossover and as with earlier Soundstream amps, all connections are made on one side. There are also two openings on the bottom of the amp with switches. One switch controls high power or high current mode, while the other allows switching between mono / coherent stereo / mixed-mono modes. The Reference 300 is rated to handle 1/2 ohm loads in stereo or 1ohm modes in mono, while in the high-current mode. High power modes are designed for loads down to 1 ohm stereo or 2 ohms mono.

See power output specs from the manual below:

Soundstream Reference 200/300/500 Power Ratings at 12v

Also, here are some of the design specs of the Soundstream Reference Series amplifiers:

Soundstream Reference Series Design Features

The ability to drive 1/2 ohm loads was a rarity back in the early 90's. Only a handful of amps were rated to handle these loads. Orion HCCA models come to mind, but there were others from US Amps and Phoenix Gold, to mention a few.

As for the power output test, I was anticipating Soundstream to rate the Reference 300 conservatively. As you may have seen already, the Rockford Fosgate Punch 150HD was rated at the same 75x2 at 4 ohms and delivered nearly 120x2 at 4 ohms on the test bench. Many manufacturers during this time rated their amps based on 12v, not the 14.4v you see today.

150 Watt Old School Amps from Phoenix Gold, Rockford Fosgate, Orion & Soundstream

So, enough talk already, how did the Soundstream Reference 300 perform on the bench? Well, now that you asked, here are the measurements (All taken based on 100Hz test tone and 13.8v input).

Continuous RMS Wattage Output: 
  • 4 ohms Stereo - 105.6 watts/ch (both channels driven)
  • 2 ohms Stereo - 134.1 watts/ch (both channels driven)
  • 4 ohms Mono - 267.3* watts (in high-power mode)
  • 2 ohms Mono - 224.7 watts (in high-current mode**)
*See the update video below for the updated 4 ohm mono test
**The Reference 300 popped it's 30A fuse when I attempted 2 ohm mono testing in the high-power mode.

See the power output test in in 720p HD or embedded below:


UPDATE: One more demo to see if the 4 ohm bridged mono mode would yield the rated 300 watts:



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