Friday, December 30, 2011

Santa Visited OldSchoolStereo - More Old School Goodies!

Yes, it's true...Santa dropped off some Old School Car Audio for everyone to enjoy!

First up is the Rockford Fosgate PBR300x4 "boosted rail" amp to match the PBR300x1 I already have and have tested in a previous video. The 300x4 is a 4 channel amp rated at 75 watts for each of the 4 channels and is not bridgeable. It is the same TINY size as the 300x1 and will work great for a stealth install. More details coming soon on this...

Next up is a rare Infinity Nucleus KPX-2 tri-mode crossover system. This item also came with the optional FC-1 fader control for Front/Rear control. Take an old school 2 channel amp and power an entire system with mids/highs up front, mids/highs in the rear and a subwoofer. The Nucleus KPX-2 offers a 12dB low pass crossover slope at 75hz and a 6dB high pass filter at 150hz.

Last, but not least is a Soundstream Dealer's manual from the mid 90's called the "Heavyweight Boxing" Subwoofer Enclosure design installation manual. It is an extremely detailed with specs of the Soundstream subs of the time (SSR, Granite and SPL models). This extra large manual was for Soundstream dealers and had an original MSRP of $249 and even has a serial number!

See the video on YouTube in 720p HD or embedded below:

See 3 of the latest items arriving at the Labs. I show off two subwoofers and an ultra-rare NIB set of Boston Acoustics 767 coaxials.

First, you'll see an early 90's Rockford Fosgate PCH-812 "The Punch" Classic 12" 8 ohm subwoofer in MINT condition. Next up is an ultra-beefy 10" sub from Eclipse, the 8810.6. This is a single 6 ohm subwoofer made by TC Sounds. 600 watts RMS, 3" peak to peak excursion and an original retail price of $370 make this a desirable sub, especially in it's very good condition!

Last up is the unbelievable...a BNIB set of Boston Acoustics 767 6.5" coaxials. Per Boston's website, these were made between 1987 and 1993. So, these speakers have been sitting in the box, untouched for possibly over 20 years? Simply amazing!

See the video on YouTube in 720p HD or embedded below:

See my latest amp arriving at the labs....a MINT Rockford Fosgate Power 500m amplifier, in the box complete with birthsheet! According to an April 1995 Car Audio & Electronics Directory, the 500m retailed for $929 back in 1995. This amp and the 250m2 were Rockford's most expensive amps as the infamous 4 channel Power 300, 650 and 1000 had been retired from Rockford's lineup around 1993 or 1994.

Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.

See the video on YouTube in 720p HD or embedded below:


Tuesday, December 13, 2011

Rockford Fosgate Power 650 Mosfet - True Old School Powerhouse

Late 80's Rockford Fosgate Power 650 Mosfet

Think old school power....think names like Orion, Precision Power and Rockford Fosgate. Up for review today is a late 80's Rockford Fosgate Power 650 Mosfet. This amp is an icon of the infamous Mosfet Power series by Rockford. People know the Power 300 as the "entry level" power series amp (MSRP $999*) and the "ultimate" power series as the Power 1000 Mosfet (MSRP $2650*). But why no respect for the big brother, Power 650? It's always tough to be the middle child! The Power 650 retailed for $1575* in 1990 and was available from approximately 1985-1993.

(*Pricing above was verified in an April 1990 Car Audio & Electronics Car Stereo Directory)

Here are the specs of the Power 650 Mosfet:

  • Power Ratings: 4 Channel
    • 4 Ohms: 125 watts per channel continuous power into 4 Ohms, 4 channels driven, from 20 to 20,000Hz, with less than 0.05% THD + N (Total Harmonic Distortion & Noise).
    • 2 Ohms: 162.5 watts per channel continuous power into 2 Ohms, 4 channels driven, from 20 to 20,000Hz, with less than 0.1% THD + N.
  • Power Ratings: 2 Channel (bridged) 4 Ohms: 325 watts per channel continuous power into 4 Ohms, 2 channels driven, from 20 to 20,000Hz, with less than 0.05% THD + N.
  • Frequency Response: 20 to 20,000Hz, ± .5dB
  • Bandwidth: 15 to 20,000Hz, ± 3dB.
  • Damping Factor: greater than 200 at 50Hz.
  • Slew Factor: greater than 2.5.
  • Slew Rate: greater than 10 volts per microsecond.
  • Protection: The Punch also employs thermal switches which protect the amplifier from overheating damage. Fuses are provided for speakers which are directly connected with no crossover components.
  • Dimensions: 18 3/10” long x 8 1/10” wide x 2” high, exclusive of knobs and wiring. 19 3/10” long x 8 1/10” wide x 2%” high, minimum mounting requirements.

Disassembled Power 650 Mosfet - Fan Shroud, Amp "guts", bottom plate and fuse cover

You young kids out there don't know much about Class A/B subwoofer amps with the $300 1500-watt Class D amps you have today. The Power 650 and Power 1000 were classic subwoofer amps in their day. Instead of using DVC subs with "fat" surrounds, we had 15's, 18's and even 30" subs (See Wayne Harris' 1985 Terminator Hearse)!!! No mention these old school subs in many cases were 8 ohms, used in multiples and had an x-max of 10 or 12mm if you were lucky...We still appreciate the "Made in the USA" quality of these amps and the pride the workers put in each and every amp. Shoot, the Rockford amps were even smacked with a rubber mallet to ensure they could handle the "punch" as part of their QA process!

One feature lacking on the Power 650 you would find on the Power 300 was bass and treble controls. For the most part, if you could afford a Power 650, you could most likely also afford a matching "Z or ZX" preamp. These preamps had EQ adjustments and even fancy LED lights as a VU meter.

Bottom side of the Rockford Fosgate Power 650 Mosfet

In addition to being a powerful four-channel amplifier, the Power 650 is also a very flexible amp. In the mid to late 1980's there were only a handful of amplifiers with built in crossovers...the Power 650 being one. Unlike modern amps, the crossover settings are set at certain frequencies (instead of being fully-variable). Also, note the high crossover's cutoff begins at 140Hz, whereas the low pass could be set as low as 70Hz. It could be used in four, three or two channel operation. My initial RMS wattage tests have shown the Power 650 ratings to be conservative, more on this in an upcoming video and article.

Early Rockford Fosgate Power 650 Mosfet with DIN and RCA Inputs

Those familiar with the Power 650's know in addition to there being DIN/RCA and RCA only models, there was also a short run of the last Power 650's with a 4-inch fan as opposed to the 2-inch model available since the mid-1980's. From my research, the 4-inch models were the last production Power 650 mosfets and were produced in low numbers. See pictures and some more detail here:

Stay tuned for the RMS wattage output demo of the Rockford Fosgate Power 650 Mosfet. Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.

See the video on YouTube in 720p HD or embedded below:


See the Old School Rockford Fosgate Power 650's in ACTION! Wayne Harris' "Terminator" Hearse Vintage 1985


Sunday, December 4, 2011

700 Watt Mini Amp? Lepai LP-V3 Tested and Reviewed

Lepai LP-V3 Mini Amp

The Chinese Mini Amp Invasion continues!! Next up is the Lepai LP-V3. This mini amp touts use of a BOSE power IC. In fact, the non-grammar corrected text "This Amplifier is use BOSE Power IC" is silk-screened on the amp. You'll also see "700 W Max Music Power" labeled on the amp. The LP-V3 uses the exact same enclosure as the LP-2020A+, I reviewed earlier.

See a size comparison w/ the LP-2020A+ below:

Lepai LP-2020A+ and LP-V3 Mini Amplifiers

In addition to touting a BOSE IC, the LP-V3 promises an RMS Power Output of 25 Watts. No clarification if this 25 Watts is per channel or total watts...

The next two pictures below show both ends of the for the controls, the other for the connections. Here again, the LP-V3 is a clone to the LP-2020A+:

Lepai LP-V3 Controls; Power, Tone/Direct, Bass, Treble & Volume

Lepai LP-V3 Connections; RCA, 1/8" inputs, Spring-Loaded Speaker Terminals and 12v5A DC  Power Input

Well, enough about the connections and controls, how does the LP-V3 sound? Well, in a nutshell, weak. I was expecting much more dynamic and punchy sound as delivered by the LP-2020A+. The LP-V3 appeared to run out of steam quickly and obviously didn't put out anywhere near the power of the 2020A+. In fact, the LP-V3, reminded me greatly of the tiny and unimpressive Kinter MA-150 I tested earlier. Very disappointing, especially considering the supposed "Real" RMS output of 25 watts. I was beginning to seriously doubt the validity of this claim. Fortunately, I have an easy way to determine the actual RMS output of this amp...

Results? Not impressive and not even close to the 700 Watt, or the 25 Watt RMS ratings. Using a 12V 35Ah Sealed Lead-Acid battery showing 13.0V of charge, I was able to obtain:

Output Test Results:

  • 4.43V RMS of Unloaded Output at the speaker terminals
  • 2.0 Watts RMS / channel at 8 ohms
  • 3.6 Watts RMS / channel at 4 ohms
  • 5.1 Watts RMS / channel at 2 ohms
  • 11.9 Watts MAX / channel at 2 ohms

(tests above were conducted using a 1kHz 0dB Sine Wave Test Tone from the SMD DD-1 test disk and output was verified by the DD-1, which detects distortion at 1%. The resistive loads of 8, 4 and 2 were conducted with BOTH channels loaded)

Stay tuned for more tests of these mini amps and see which one (if any) you should buy. Check out my video review of the Lepai LP-V3 below. Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.

See the video on YouTube in 720p HD or embedded below:



Wednesday, November 30, 2011

500 Watts in Your Pocket? Kinter MA-150 Mini Amp

Kinter MA-150 vs. CD: Size Comparison

The promise of 500 Watts in a palm-sized amplifier is appealing to many people. The Kinter MA-150 is another contender in my Chinese Mini Amp Invasion shootout and is the smallest amp in the bunch. Although technology such as "Boosted Rail" has enabled Rockford Fosgate to make the PBR300x1 just slightly larger, it "only" promises 300 Watts of power at 1 ohm. Not to mention, the PBR300x1 costs around 10x as much as the Kinter MA-150...

I picked up the Kinter MA-150 from an eBay seller for around $15 US shipped from China. Now, logic will tell us we shouldn't expect much from an amp only costing a few dollars, right? Yes, this is a rational thought. "You get what you pay for" comes to mind. So, what does the $15 get you? Continue reading...

The Kinter MA-150 has a slightly different design than the other amps in this shootout as it requires molex-style plugs for the speakers and power. The other amps in this comparison have spring-loaded speaker terminals and a 5.5mm x 2.1mm center positive power plug.

Kinter MA-150 Speaker Output and Power Inputs

The opposite side of the MA-150 has a USB port for charging external devices, RCA L/R jacks, Volume knob and crossover switch. See picture below:

Kinter MA-150's USB, RCA, X-over and Volume adjustments

For more details on the technical specifications, please see the Chinese Mini Amp Invasion article for a spreadsheet comparing each amplifier in the shootout.

The Kinter MA-150 is heavily marketed on eBay as a motorcycle or scooter amplifier. Obviously, the main reason is the small size, low power consumption and "rated" high-power output. Now, logic and science will tell us, based on the MA-150's 12v 0.5A power requirement, you can use the equation Watts = Volts x Amps to get 12 x 0.5 = 6. Taking into account 100% efficiency, the amp should put out 6 watts, based on the power going in. Well, unfortunately, the amp is NOT 100% efficient, so even the 6 watts may be a stretch.

Power ratings vs. actual output aside, I decided to run the sound quality test first. I tested several tracks, including one of my favorite "Chelsea's Day" by Sam Cardon. It was readily appearant to me the MA-150 didn't have the power, clarity or dynamics of the Lepai LP-2020A+ . My reference speakers, the Athena Point 5 MKII bookshelf speakers are extremely transparent and it was obvious the MA-150 was struggling to push them to room-filling level. Again, based on the output I was expecting, this wasn't a surprise to me. After a few minutes demoing my reference tracks, I decided to put the MA-150 on the test bench and get some actual numbers.

Results? Not impressive and not even close to the 500 Watt rating. Using a 12V 35Ah Sealed Lead-Acid battery showing 13.0V of charge, I was able to obtain:

Output Test Results:

  • 4.56V RMS of Unloaded Output at the speaker terminals
  • 2.1 Watts RMS / channel at 8 ohms
  • 3.4 Watts RMS / channel at 4 ohms
  • 5.3 Watts RMS / channel at 2 ohms
  • 15.6 Watts MAX / channel at 2 ohms

(tests above were conducted using a 1kHz 0dB Sine Wave Test Tone from the SMD DD-1 test disk and output was verified by the DD-1, which detects distortion at 1%. The resistive loads of 8, 4 and 2 were conducted with BOTH channels loaded)

Stay tuned for more tests of these mini amps and see which one (if any) you should buy. Check out my video review of the Kinter MA-150 below. Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.

See my video review / bench test of the Kinter MA-150 and decide for yourself if this is the amp for you...


Saturday, November 26, 2011

Chinese Mini Amp Invasion! Kinter, Lepai and More

Mini Amps Galore! 3 Models from Kinter, 3 from Lepai and 1 from TeLi

If you spend anytime on eBay looking at car audio amplifiers, then you've surely come across some of the amps I'm going to talk about here. Lepai and Kinter are just a few of the brands you'll see quite often. Some of these mini amps are small enough to fit in your pocket and promise 500 to 700W of power. So why spend several hundred dollars on a fancy name brand amplifier when you can pick up most of these for under $20 US shipped? In the near future, I'll test each amp for RMS Watt output and with some reference speakers and we may soon see why.

After receiving and testing my first mini amp, the Lepai LP-2020A+, I decided it may be interesting to pick up a few more of these mini amps and have a shootout! Here are the models I've obtained thus far:

Lepai Amps:

  • LP-2020A+ - my first mini amp, rated at 550W MAX (20W RMS) output. Tripath design, TA-2020, 2-channel, RCA/3.5mm input, bass/treble/bypass, large volume knob w/ blue LED backlight. 4-8 ohm compatible, 9-13.2V 4A power requirement (per box, amp says 12V 2A?). S/N ratio >80dB
  • LP-V3 - "This amp is use BOSE power IC" (my favorite amp quote). Rated at 700W MAX (25W RMS) output, identical in size to the LP-2020A+ (so why the 700W rating?). 2 channel, RCA/3.5mm input, bass/treble/bypass, large volume knob w/ blue LED backlight. 2-8 ohm compatible, 9-14.4V 5A power requirement (per box, amp says 12V 2A also). S/N ratio >80dB
  • LP-168HA - 2.1 (3 channel) design with ratings of 40x2 and 68x1 watts. Has separate volume for bass, built-in x-over, bass/treble/volume (all same size). RCA/3.5mm inputs, USB port, spring-loaded speaker terminals for Front L/R and Sub. 14.4v 5A power requirement.
Kinter Amps:
  • MA-150 - the smallest amp in the group, rated at 500W MAX. BTL desigh, filter for L/Off/H (x-over?), RCA L/R inputs, speaker/power connections by molex-style plug w/ attached wires. 12v 0.5A power requirement
  • MA-170 - Similar design to the Lepai LP-2020A+, but smaller. BTL design, 2-channel. Large volume knob, bass/treble adjustments, sprint-loaded speaker terminals, RCA L/R inputs. 9-14.4V DC power requirement, no Amperage specified. Rated at 100W PMPO or 4W x2 RMS, S/N ratio >70dB
  • MA-200 - largest amp in the group. 4-channel design using 2x TDA7377 IC's, rated at 41W x4 channels RMS at 1kHz. Has equal size knobs for treble/bass/volume. Includes display for function display; AUX or FM. Includes input for USB and SD/MMC card. 12V 5A power requirement.
TeLi Amp:
  • A6 - identical in size to the Kinter MA-170. 2 channel, BTL design, RCA/3.5mm inputs, bass/treble range +/- 15dB. 8-15V DC power requirement (no amperage mentioned)

See the latest Spreadsheet below with specs comparison or download it if you prefer:

Stay tuned for upcoming tests of each mini amp and we'll see which one (if any) you should buy. Check out the video overview of each amp below. Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.



Big 'Ol Stack of Mini Amps!

Kinter MA-150 in Orion HCCA Red

Friday, November 18, 2011

SMD's DD-1 - New School Tool for Old School Amp Testing

SMD's DD-1 "Distortion Detector" vs. Velleman HPS50 Oscilloscope

Many of you who follow my blog and videos, know I've had a Velleman HPS50 oscilloscope for a while now and keep adding components to enhance the capabilities of my test bench. My primary focus now is testing amplifiers for maximum continuous RMS wattage output. We all know most of the ratings we see on amps today are not RMS, but MAX output. This is a marketing ploy, not useful at all in determining the actual output of an amplifier. I'll soon get one of these amps on the bench and show you actual RMS wattage output vs. the value claimed on the amp. You may be amazed and not laugh so much at the old school amps and their low wattage ratings...

I recently decided to pick up a SMD DD-1 "Distortion Detector". This device was developed by the brains at D'Amore Engineering in conjunction with the KING of car audio on the Internet, Steve Meade ( Steve Meade (meade916 on YouTube) is famous for his 30,000 watt custom Chevy Tahoe and has several hundred videos. Steve is also the largest car audio channel on Youtube with over 100,000 subscribers and over 100 MILLION video views. Impressive to say the least, but this DD-1 is not hype, it is a truly powerful and affordable tool for everyone from electronics enthusiasts to car audio shop installers and many in between.

So, what's the deal with this DD-1 and why might you want one? The SMD DD-1 is marketed as an amplifier gain matching tool. Matching your car audio head unit and amplifier has been a black art for many years. Without an oscilloscope and test tone, setting gains was really just a guess for most folks. The DD-1 costs only a fraction of most oscilloscopes and offers simplicity in setting/matching gains for your car audio equipment.

Here's what's included in the package:

  • The Distortion Detector (DD-1)
  • Protective silicon rubber boot
  • Calibrated Test Tone CD
  • Harness
  • Printed owner's manual

According to the manual, the DD-1 has the following specs:

  • The DD-1's circuitry is 100% analog
  • Distortion Detection trigger level > 1.0% Harmonic Distortion
  • Guaranteed operating range of input signal is 1.2Vrms - 125Vrms (15,000 Watts at 1 ohm) Autoranging
  • Signal Present LED trigger voltage 750mVrms
  • Low Battery LED trigger battery voltage < 5.6Vdc
  • Auto shut-off timer 8-10 minutes after on button is pressed

Now, I must be honest. The unit's ability to match gains is a great feature, but I've had this ability with my Velleman HPS50 portable o'scope for a while. A recent video on Steve's channel about the upcoming AD-1 "amp dyno" got the wheels spinning in my old school head. This DD-1 can be used for more than just matching can be used to assist in amplifier output testing! This feature in a sub $200 device is unheard of. A bench version of a THD analyzer can cost MANY thousands of dollars. I've been watching eBay for a year or more hoping to find a deal on one of these THD analyzers so I could verify distortion during my amplifier tests. After seeing the AD-1 demo, I was convinced to buy the DD-1 to use as a tool in my RMS output tests.

The DD-1 has proved to be an invaluable tool and will ensure accuracy in my amplifier tests. I have MANY old school amps I plan on testing in the upcoming months. The DD-1 will ensure < 1% distortion in my results which is great. As I mentioned above, not only do many manufacturers rate amps by "Max" output, they also sometimes use distortion numbers up to 10% for their ratings. I think it's important to keep the distortion less than 1%, which should be inaudible for most people.

I have done some initial tests with the DD-1 and have been impressed with it's ease of use and ability to detect low levels of distortion. See some videos below and be sure to subscribe to my YouTube channel to stay updated with the latest amplifier and car audio tests and demos.

Buy the DD-1 Direct at




Friday, November 11, 2011

Can The Orion Take The Punch?

Rockford Fosgate Punch 45HD and Orion 222 SX

The Rockford Fosgate Punch 45HD and Orion 222 today's terms would be called "tweeter amps". Go back 20 years to 1991 and people were using these amps not only to power subwoofers, but in some cases entire systems! Since both amps were rated at 45 watts or less at 4 ohms (both channels), people either had really efficient speakers or didn't require high volumes, right?

Well, many people were told and believe the old school amps are always "very" or "highly" underrated. Read on to find out if this is the case with either or both of these mini powerhouses.

First up, the Orion 222 SX appears to have a heat sink surface area advantage at 8.5 x 8.5 x 2.25 inches. It carried an MSRP of $329 US back in 1991 (reference - Car Stereo Review, July/August 1991) and included the following specifications from Orion:

222 SX Ratings at 12 VDC (both channels driven):

4 ohms stereo - 22 watts RMS
2 ohms stereo - 44 watts RMS
4 ohms mono - 88 watts RMS
(not rated to handle 1 ohm stereo or 2 ohm mono loads)

More Specifications:

  • Requires external 15A Fuse, 20A provided by Orion (according to the manual)
  • Stereo, Mono or Mixed-Mono operation
  • Left and Right Peak Power LED's
  • 0.005% THD at rated power
  • Damping Factor - Greater than 500

On one side of the 222 SX are the power/ground wires (10 gauge), plus the 9-pin molex connector for speaker and turn on connections (See my Youtube Video on how to make these yourself!). The opposite end of the amp has input connections from both RCA and DIN connections. The DIN connection supports Orion EQ's and crossovers and provides phantom power for these devices as well. There are also two buttons, one for "EQ", providing a +15dB boost at 40Hz, -4dB at 200Hz and +6dB at 10kHz, in addition to a "Mono" button for bridging the amplifier. The 222 SX also has Peak/Power LED's and a single input gain control. See the connections below:

Orion 222 SX input connections, Peak/Power LED's, Gain control, EQ and Mono buttons

Next up may be Rockford Fosgate's most well known amp from the mid-80's to early 90's, the Punch 45. In 1991, Rockford updated their vulnerable Punch 45 to the Punch 45HD, aka "Hybrid Design". Again, many competitors in the late 80's/early 90's used a single Punch 45 to compete in the 50-watt and under class.

The 45HD required spade connectors for the power and ground inputs. The opposite side includes; speaker/remote connections via 6-pin Molex plug, Bass/Treble knobs, Left/Right RCA Inputs and gain controls for both channels.

(Top) Rockford Fosgate Punch 45HD's 6-pin molex connector, bass/treble controls, left and right RCA Inputs and Gains

The slightly smaller heat sink of the 45HD measures 6.6" long  x 8.6" wide x 2.2" high and carried an MSRP of $275 back in 1991 (reference - Car Stereo Review, July/August 1991).

Punch 45HD Ratings at 12.5 VDC (both channels driven):

4 ohms stereo - 22.5 watts RMS
2 ohms stereo - 35 watts RMS
4 ohms mono - 70 watts RMS
(not rated to handle 1 ohm stereo or 2 ohm mono loads)

More Specifications:

  • Requires external 15A Fuse, 20A can be substituted for "extreme" loads
  • Stereo, Mono or Mixed-Mono operation
  • 0-18dB Bass Boost at 45Hz, 0-12dB Treble Boost at 20kHz
  • 0.05% THD at rated power
  • Damping Factor - Greater than 200 at circuit board, greater than 50 at speaker leads


Now you've read about the ratings and specifications, do you have a choice between the two for powering a single 8" subwoofer? I realize these amps may not be well suited to drive subwoofers, but this is OldSchoolStereo and I'm taking the test back to the old school!! Luckily, I have an early 90's JL Audio 8W1 (4 ohm) which will be the perfect test sub for these amps. In addition to the subwoofer test, I'll also test resistive RMS wattage output from both amps at several ohm loads.

Now, the question I'm sure many of you are asking....did I have a favorite before the tests? Well, I must admit I've tested the Punch 45HD before and knew what to expect from this little "punch". That said, I had high hopes for the 222 SX based on how well the Orion 275 SX fared against the Punch 150HD and Phoenix Gold MS-275. This is a CLASSIC shootout as I expected the results to be very close. I can't go without saying I broke the rule of my YouTube channel saying I wouldn't do "woofer flex" tests. I just couldn't resist seeing how these baby amps pushed the JL 8W1. I also used my Zoom H4 audio recorder for GREAT quality bass without distortion. Just make sure you use your headphones while watching the YouTube video to get the best experience (well, unless you are watching this on your home theater with an 18" powered sub...)

I put the Orion 222 SX on the bench first and connected up the resistor bank, 1000Hz test tone and Velleman HPS50 oscilloscope/true RMS Volt meter. Results are:

Sunday, November 6, 2011

Rockford Fosgate PBR300x1 "Boosted Rail" Amp

Old School Orion 222 SX vs. Rockford Fosgate PBR300x1

As we all know, technology has a way of "shrinking" electronics over time. Have you ever seen an early laptop computer? Or how about a 1st generation iPod? Compared to the latest laptops and iPods, the first generation models are large and clunky.

Transition over to car audio amplifiers. Although this is, I still appreciate technology and have been eager to try out one of the new "mini" amps currently on the market. One which grew particular interest is the Rockford Fosgate PBR300x1. This amp measures a tiny 6-3/4"L x 4-1/4"W x 1-1/2"H, small enough to fit in the tightest automotive locations. Here are the full product specifications:

  • mono subwoofer amplifier
  • 75 watts RMS x 1 at 4 ohms (150 watts RMS x 1 at 2 ohms)
  • 300 watts RMS x 1 at 1 ohm
  • CEA-2006 compliant
  • Boosted Rail amp technology
  • Dynamic Thermal Management cooling system
  • variable low-pass filter (35-250 Hz, 12 dB/octave)
  • differential-balanced inputs eliminate noise from your vehicle's electrical system
  • preamp and speaker-level inputs
  • optional wired remote bass boost (0-18 dB at 45 Hz)
  • 10-gauge power and ground leads and a 30-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 30-amp in-line fuse between the distribution block and the amplifier is recommended
  • 6-15/16"W x 1-9/16"H x 4-5/16"D

  • Something I noticed immediately after opening the box was the inclusion of molex-style connectors for the amp. Am I missing something here or are we going back to the early 1990's? I couldn't help to think of the 1991 Punch 30HD which uses similar connectors. See pictures below for all of the connections, plus a size comparison to the 30 watt Punch 30HD.

    PBR300x1 connections including crossover, gain, hi/low input and Remote Punch EQ

    PBR300x1 Speaker output and Power connections

    2011 PBR300x1 vs 1991 Punch 30HD - 300 watts vs. 30 watts!

    Ok, so an amp almost small enough to fit in your pocket can deliver 300 watts? Well, according to the birthsheet included with my PBR300x1, it will actually do 315 watts RMS at 1 ohm (14.4v)! Impressive numbers from such a small amp, but how does it sound powering subwoofers?

    Well, you can see (and hear) first hand by watching my video below. I auditioned the PBR300x1 on my test bench with subwoofers including; 8" JL Audio 8W1, 10" Kicker Solobaric S10c and 12" JL Audio 12W6v2 D4. The results were impressive, to say the least. I'm really looking forward to getting the amp in my daily driver for a true test of this little beast and how it performs in the harsh automotive environment.

    Stay tuned for an upcoming power output test of this amp. 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:



    Thursday, November 3, 2011

    Recent Arrivals to the Labs

    I've recently done several unboxings on my YouTube channel. I'll have more articles and tests in the near future, but for now, enjoy the videos!

    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:



    Make sure you subscribe to my YouTube channel to stay notified of the latest "old school" car audio videos. Much more exciting tests, demos and information coming up soon...


    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:



    Keep watching and subscribe to my YouTube channel to stay updated with my latest Old School Car Audio tests and demos.


    Thursday, September 22, 2011

    Unboxing Old School Car Audio Gear

    I will be the first to admit, unboxing videos do not appeal to me. Why? Mainly because people do unboxings for things like cameras, camcorders, computers, etc. and there is no excitement factor there. Now, take a plain brown box (with unknown goodies inside), open this up on camera and share your excitement with the world! This is how BigDWiz does unboxings at the OldSchoolStereo labs!

    First off, I must say not all of the unboxings I do on my YouTube channel are from purchases. Many are from trades and barters for other gear. This is a part-time gig for me and I don't have unlimited funds to buy all of this cool, old school equipment. Well, since I know opening these packages is exciting for me, I thought you guys might enjoy the experience? Mystery Box!

    Finding nice, old school car stereo gear is exciting in itself, but opening a package with unknown contents (well, unknown to you) is fun for all. Those of us who enjoy the old school gear also love to see "timeless classics"...the amps, speakers, head units, etc. that have either been babied or unused all of these years. I still find it amazing to see the condition of some of my 25+ year old equipment.

    Most of these videos will just show the unboxing process, but in some cases, I may hook up and test the contents. Honestly, it just depends on how I'm feeling at the current time (and how much space is remaining on my iPhone's internal storage!). This brings up another interesting point....some of you may wonder what equipment I use to record and produce these short videos. Well, I have two words for you; iPhone and iMovie (we won't count "and" as a word!).

    Recently, I've discovered making videos with the iPhone 4, is not only a simple process, but also gives a pretty good output video for viewing online. I also ensure use of the included ear buds / mic combination to get better audio, while still leaving both hands free to tear open the boxes. Once I capture the segments on my iPhone 4, basic editing is handled by the iMovie app for the iPhone. This $5 app turns your iPhone into a VERY powerful hand-held editing machine. If there is any interest, I may show the process I use to capture, edit and upload my videos to YouTube. You guys just let me know by making comments here or on my YouTube Channel.

    While you are visiting, please Subscribe to my channel so you can get notification when I upload a new video. My intentions are to upload a new video every few days. As I've mentioned before, the more subscribers, comments, likes, etc. I have, the more videos I'll put up. I appreciate your enthusiasm as being an "old school nut" is addictive!

    Unboxing Old School Car Stereo Gear


    Unboxing Old School Car Stereo Gear #2


    Unboxing Old School Car Stereo Gear #3


    Unboxing Old School Car Stereo Gear #4

    More text

    Thursday, September 15, 2011

    Old School PPI Pro Mos Amps - Precision Power!

    Most of you old school car audio fans know the early 1990's was a time when aftermarket car audio was getting extremely popular. At this time, it was rare to find a factory CD player and the factory speakers were weak at best in most cases. Manufacturers such as Rockford Fosgate, Linear Power, Precision Power (PPI), Autotek, Orion and Soundstream (to name a few) were some of the very popular aftermarket car audio brands at the time.

    The competition between the manufacturers was intense and each one was trying to best the other. Orion's HCCA series amps, released in the late 1980's were extremely popular and had an edge power wise on most other amps with their rating and ability to handle extremely low ohm loads. These low-wattage rated / low ohm handling amps came to be known as "cheater amps". The cheater amps could put out as much as 8x their rated 4 ohm power rating at lower loads. PPI hit the "cheater" market in 1990 with the Pro Mos 2050. Pro Mos was short for Professional Mosfet. This first gen Pro Mos amp was rated to handle loads down to 1ohm and would provide 4x it's rated 4ohm power at 1ohm. Cough up around $800 for a 50x2 amp, and get a 400x1 monster when loaded down. Interestingly enough, Orion's 25x2 "cheater", the 225 HCCA was stable down to 1/2 (some even say 1/4) ohm loads and would put out in excess of 400 watts and cost less than $600.

    I've shown a comparison of the Orion 225 HCCA and the PPI Pro Mos 25 in a previous posting and video. You can see my preliminary power output results HERE.

    PPI Pro Mos 2050 (top), Pro Mos 12 & Pro Mos 25 - Image (C)

    These Pro Mos amps were available up until around 1995, adding additional models including the Pro Mos 12, 24 and 50 (replacing the 2050) beginning in 1991. They also released 4 channel models; the Pro Mos 425 and 450. These Pro Mos amps were no frills, offering no internal crossovers or bass/treble controls. They offered a DIN connection for powering a PPI pre-amp or crossover in addition to the standard RCA input jacks. The Power and Ground connections were made via 8 or 10 awg leads and the speaker/remote connection was made by an infamous molex connector. I say infamous because this connector has been a huge failure throughout the years. The wires don't stay inside the connector and the molex connector itself breaks very easily. Many people created terminal strips or soldered the leads to the circuit board.

    The Pro Mos amps you see in the photo above are the "art series", finished in white including a unique design by an artist. These amps were also available in black with red lettering.

    See the video demo below:

    Also, visit YouTube and subscribe to my channel for more exciting OLD SCHOOL car audio gear!



    Saturday, September 10, 2011

    Vintage Fosgate Car Amps - PR 220 & PR-250 Pre-Rockford

    Fosgate PR-250II and PR 220 Vintage Car Audio Amplifiers

    I decided to dig out some real dinosaurs in the car audio world....the Fosgate "The Punch" PR 220 and PR-250 Type II amplifiers. These amps were produced by Fosgate Electronics, Inc. in the late 1970's before Rockford joined Fosgate. I believe the PR-250 was 1978 or 1979 and this model was also produced in 1980 as a Rockford Fosgate PR-250II (logo was different than the one pictured above). The PR 220 was also late 1970's, found in the 1978 and 1979 Car Stereo Directory issues of Audio magazine, but not in the 1976 issue. I don't have the 1977 issue to see if they are listed there...

    These amplifiers were state of the art at the time they were produced. Just think, in the late 1970's, many people were still rocking 8 tracks and a cassette player was "high-end". I don't believe there were many (if any) head units with pre-outs at the time. You definitely were lucky to have one of these back then. Don't forget, 3-way 6x9's were considered high-end at this time! Take your PR-250, power up the Sony tape deck and Jensen or Sparkomatic 6x9's and you were rockin'!!

    Another view of the Fosgate "The Punch" PR-250 Type II / PreAmp & PR 220 Amplifiers


    The Fosgate PR-250 Type II had a matching Pre-Amp, which controlled the unit's volume, bass and treble controls. The volume knob was a smooth rotating potentiometer, while the bass and treble controls had a "clicking" type potentiometer (meaning you had only a certain number of positions, by turning these knobs, it would click into position). The PR-250's pre-amp had only two connections, both DIN style plugs. One DIN cable would be integrated in with your head unit and the other would carry the signal from the pre-amp to the PR-250 amp. Then, you would need some speakers capable of handling 50 watts RMS per channel, not the easiest task in the late 70's...The PR-250 was also bridgeable or capable of handling loads more demanding than 4 ohms.

    The Fosgate PR 220 was much simpler and less powerful than the 250. It was rated at 20 watts x 2 channels into 4 ohms, no options for bridging or lower ohm loads. It also came without a pre-amp, all controls (bass and treble) were on the amp itself by 3-way sliders. Your options were low/mid/high for bass and treble adjustments. Again, speaker level inputs were the only signal source allowed into the amp and since most head units were only good for a couple of watts, the 20 watt PR 220 was a decent upgrade and would drive efficient speakers to loud (at the time) levels, around 110dB. Fosgate had a warning in the manual, "Sound levels of 110 dB have been recorded inside a car using the PR-220 and High Efficiency speakers. This is loud enough to lead to permanent loss of hearing after long periods of exposure. So use common sense.."

    Photo (c) 2011 - Dereck Willis -


    So, you know me, I'm good for putting up video demo's right? Well yes, I have posted an overview of the amps below. That said, don't get too excited about seeing these amps in action as I'm a little hesitant to power them up. The PR 220 at least needed to pull power from the head unit for the remote turn on.

    Quote by tomtomjr, one of if not the US's largest Fosgate/Rockford Fosgate collector and radio/amp technician:

    " ...ALSO, on the turn on remote wire (red) , you will need to draw power from it to turn on the amp. We used to use a 12V light bulb and a switch. Put the remote wire (red) to the positive of the bulb, then the switch between the 12V ground and the 12V ground of the bulb. Flip the switch, and it will come on. These have the power-draw on the remote wire rather than the power input like modern amps... Hope this info helps........Tom"

    See the video demo in 720p HD or embedded below:



    Thursday, September 8, 2011

    Saturday, August 27, 2011

    The World's Most Powerful iPod Dock? Athena iVoice

    Athena iVoice iPod Dock

    What is the world's most powerful iPod dock? Is it the Athena iVoice? Well, not likely, but I decided to test one of these iVoice docks on the oldschoolstereo test bench. I have one of these units with a bad speaker, so I decided to pull it apart and test the amplifier using my resistor load.

    The Athena iVoice is an amazingly good sounding iPod dock. I've been VERY impressed with these docks since I first purchased one on closeout a few years ago. The unit also has a 1/8" input so you can also use it with other portable music devices, computers, cell phones, etc...any device with a 1/8" output. Trust me, you won't believe the sound coming out of dual 3.5" speakers! The bass is very punchy, mids extremely transparent and even the highs will surprise you. Another useful feature of the Athena iVoice is the built-in power supply. No external power brick needed with this dock! (just a light-weight 6 foot power cable) Probably the only real downside is the lack of an internal battery for portable usage. The dock also includes a USB port for iTunes syncing and a RCA video output for passing signals from an iPod Photo or iPod Video 5G (not sure about 5.5G or iPod "Classic"?). My iPhone 4 fits on the dock, but will not charge and gives me a "not compatible" warning. That said, it will pass audio from the iPhone.

    Athena iVoice with Metal Speaker Grill Removed

    Athena iVoice Rear Connections

    Here are the iVoice specs from Athena:

    Design:Direct Radiating iPod Dock Sound System
    • Wall mountable - Provides Greater Installation Flexibility
    • USB Connectivity - Allows the iPod to Sync with iTunes on your Computer
    • IR Remote Control - Remotely Controls your iPod and the iVoice
    • Charges iPod While Docked
    Frequency Response:65 Hz — 17 kHz
    System Power:25 Watts RMS / Channel
    Input:3.5mm Audio Input - Can be Used with Any Portable Audio Device (with an Audio Output) or Computer
    Output:Composite Video Output - Allows an iPod Photo / Video to Output Video Content to an External Display Device
    Dimensions — Standard:
    (Height x Depth x Width)
    5" x 15-½" x 6-½"
    Dimensions — Metric:
    (Height x Depth x Width)
    140cm x 393cm x 170cm
    Weight:4.7 lbs / 2.1 kgs

    Polished High Gloss Black

    Well, enough talk about the sound and specs of the iVoice, what about the output power? Athena says 25 watts RMS per channel, which honestly, is a LOT of power for 3.5" speakers. My test involved sacrificing one of my iVoice docks, so see the internals below:

    Athena iVoice Internal Components

    As you can tell by the pictures, the 3.5" speakers appear to have neodymium magnets and a dual-cone design for enhanced highs. A quick measurement of each speaker show a load of approx. 6.8 ohms. Since my resistor loads are setup for 8, 4 and 2 ohm configurations, these are the loads I decided to use for my testing.  I honestly wasn't sure the tiny "BASH" Class D amp could handle the 2 ohm tests, but decided to do it anyway...why not?

    So, did Athena accurately rate the internal amplifier? Well, I guess it depends on the testing parameters they used. For my 1000 Hz tone resistive load test, the amp seems to be somewhat overrated. See the video for the detailed test results, but the approximate measured RMS wattage was 10, 20 & 32 (at 8, 4 and 2 ohms, respectively). 

    Although the Athena iVoice may not be the world's most powerful iPod dock, it is the most powerful iPod dock measured on the oldschoolstereo test bench! (as of August 2011)

    Watch the demo in 1080p HD or embedded below: