More 90's Cheater Amps Coming Soon...

What's up old school fans? Sorry, it's been too long since my last post. I have acquired a few more "cheater" amps from the 90's I'll be testing soon. I've decided to stick with the "50 watt" (25x2) cheater amps as these are more affordable and easier to come by.

Here's a 1992'ish US-Amps US-50HCA, high-current, competition 25x2 amp:

US Amps US-50HCA - 1992 Model in 9.5/10 Condition

Another popular 25x2 cheater amp from the 90's was the HiFonics Ulysses. This mode is the Ulysses VIII, which has the Utilink connectors for speaker and power. Unfortunately, my amp was missing these connectors and since Zed stated these connectors are no longer made (the power connectors were specifically tooled for these amps and no longer manufactured). The speaker connectors are easier to come by. You can either spend $15-20US on eBay or search the Digi-Key catalog for a suitable replacement. I chose the latter.

Fully Polished 1996 HiFonics Ulysses VIII

More details on these cheater amps and maybe I'll be able to come across a few more to include in my shootout. I'm looking for 1) MTX 225HO 2) MTX MTA 225 (clone to the PPI Pro Mos 25) 3) Autotek 9050BTS and a few more I can't think of right now.


Here is the list of 90's cheater amps thus far for my shootout:

1) Rockford Fosgate Punch 45HD
2) Precision Power Pro Mos 25
3) Phoenix Gold MPS-2240
4) Orion 225HCCA (Gen2 and Gen3)

5) US Amps US-50HCA

6) HiFonics Ulysses VIII

So, how will I perform the shootout? Well, I'm thinking a true power output test using my dummy loads and oscilloscope as the first test. I plan to have the means of testing loads from 4ohms down to 1/2 ohm. Obviously, I'm not going to load amps, such as the Punch 45HD lower than 1ohm as it was not intended to handle extremely low impedance loads as some of the others were. Many people may argue the Punch 45HD should not even be considered as a cheater amp, but those people can do their own shootouts!

In addition to the power output tests, I'll also demo each amp powering one or more subwoofers. It will be interesting to see if the most powerful amp also controls the subwoofer(s) best. We'll find out soon enough...

-BigD

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Update: 6/27/11

Many of you have contacted me asking why am I taking so long to post the shootout between the cheater amps I have listed above. Honestly, I was hoping to get the HiFonics Ulysses VIII amps repaired as they were both dead. My repair tech said it would be about $100/ea to have them fixed and since I needed some other amps repaired, I decided to trade in the Ulysses amps. That said, I won't be getting them back, so I'll have to remove them from the test. I've seen a few Autotek 9050BTS's lately, so maybe I'll be able to pick up one of those for the shootout.


In addition, the Phoenix Gold MPS-2240 is experiencing the same issue as many 90's Phoenix Gold amps....leaky output capacitors. These capacitors will need to be swapped prior to any further testing with this amp. Too bad as it may be several months before I'm able to get around to having it repaired. 


Stay tuned for updates....

Old School Cheater Amps - RMS Power Output Test Results

I'm sure many of you have been eager to see my test results from my previous posting on early 90's "cheater amps". Well, I've finally assembled the pieces needed to test RMS power output from the amps. See my previous post for details on my testing methods.

Did I have any favorites? I must say, I thought the Orion 225HCCA would take top honors, but envisioned the Phoenix Gold MPS-2240 would be close behind. Although the Rockford Fosgate Punch 40i DSM was not included in my original "cheater amps" posting or the video I created, I felt it was a worthy opponent to the similar amp models. I put together a separate video on the Punch 40i DSM a while back and it nearly blew me away with it's power and clarity....I guess I was unaware of just how underrated this little amp is!

The Precision Power Pro Mos 25 was no slouch either. It wouldn't win the price/performance ratio, but it outputted 1.5x or greater it's rated output at all test loads. Since this is not a sound quality test, the only comparisons were RMS output power. The PPI Pro Mos 25 would probably gain points to some people for it's "Art" design, but I was always a bigger fan of the black series PPI amps. Also, in the old school, lacking bass and/or treble controls would be another minus for me.

The venerable Punch 45HD was a favorite back in the early 90's and for good reasons. It was reasonably priced ($279 US) and put out at least 2x it's rated power at 2 and 4 ohms. As I've stated in the past, Rockford didn't rate this amp to handle 1 ohm stereo or 2 ohm mono loads; however I've had a Punch 45HD since December 1991 and used it for several years in the 2 ohm mono configuration with no issues whatsoever. It was interesting to see the power output lower in the 2 ohm mono test than the 4 ohm mono test with the Punch 45HD. The limiting circuitry must have come into play to protect the amp from overload.

The Orion 225HCCA and Phoenix Gold MPS-2240 were the only two amps in my test rated to handle 1 ohm mono or 0.5 ohms stereo loads. Unfortunately my current setup provides loads down to 2 ohms and no 1 ohm or 0.5 ohm configuration. I'll add more resistors in the future and test these amps again to find out their full output potential. I have little doubt the Orion 225HCCA will output over 500 watts but have less optimism in the Phoenix Gold MPS-2240...especially when comparing the 4 ohm mono vs. 2 ohm mono loads with this amp.

I hear ya, enough with the jibber-jabber, on with the results! See the embedded spreadsheet below or Click HERE to see the full size image:

Testing Power Output from Old School Amps

Old School friends, have you ever wondered how underrated your treasured amps are? Well, I must say I've always wanted the ability to measure actual output from my amps to show we did actually get what we paid for.

My wishes have come true with the latest 2 items I've added to my test bench....an Oscilloscope and a "dummy load" (aka "Fred Sanford") resistor bank. The o'scope is a portable model by Velleman (HPS50) and the resistor bank is one I put together based on another project I found online. See the detailed layout here:

400W Dummy Load Project

I essentially took his design and doubled it. This gives me (2) 400W loads at 4ohms or (1) 800W load at 2ohms. These resistors can handle up to 3x their rated power for short periods of time. I had originally planned on using 32 instead of 16 resistors, but then decided I could add more in another enclosure as needed. Here is a pic of my creation:

So some of you may be wondering what the resistors are used for. Basically, they are designed to handle the output power from the amps without producing any sound. This allows you to reach max output without damaging your hearing. After I did a simple test with an old Realistic speaker, there was no doubt I needed to build a Fred Sanford. Not to mention, I can safely test many different frequencies, including 1000Hz, which is not pleasing to hear at high volumes!


Next, I needed an oscilloscope to monitor the waveform from the amp. I considered many models, including desktop and portable designs. I finally settled on the Velleman HPS50 portable oscilloscope. I purchased from Kitsusa.net and it was around $230US shipped. I also considered the HPS10SE, but it did not have USB output for monitoring / capturing via PC, which I thought may be important. Another selling point for me of the Velleman o'scopes is the built-in audio measurement tools. They essentially have a built-in True RMS Volt meter and taking the AC Volts x AC Volts and dividing by the ohm load you get max output power (The Velleman does the math for you and just shows power output). The HPS50 will also let you decide between MAX power and RMS power. I decided to perform all of my tests using the RMS power measurement.

Components used in my testing include:

• 100A Audio Authority 978 13.8V Power Supply
• iPod Nano (1st Gen) with test tones - 100Hz and 1000Hz
• 1/8" to stereo RCA adapter
• 12ga Speaker Wire to Connect Amp to Dummy Load
• Windows XP laptop to monitor/capture live waveform from HPS50
• Velleman HPS50 Portable Oscilloscope
• 800W Dummy Load Resistor bank (AKA "Fred Sanford")
  

So, I bet you are curious about some of my findings....stay tuned as I'll post results very soon....

-BigD

Velleman HPS50 Portable Oscilloscope for Testing Amp Output Power

I finally got a chance to test the Velleman HPS50 today. It was pretty simple to setup, even for the o'scope novice like myself.

I don't have my dummy load resistor bank yet, but I do have a 6.5" Realistic Dual Cone car speaker I was willing to donate to the cause. I measured it's resistance to be 4.2 ohms.

I used a 100Hz test tone for my tests and calibrated the HPS50 per the instructions. First, ensure the switch on the probe is set to 10x, also check the display to ensure 10x. Then use the tip of the probe to touch the calibration point on the side of the scope. Lastly, view the waveform, and adjust the small screw on the probe until the wave form has even square waves. (I was wondering what the small, plastic screwdriver was for in the box, now I know!)

You have a few choices for measuring power output. I initially tested Peak watts, then decided RMS was a better test. In the HPS50, it is displayed as W^4Ω. You can also set the ohms (Ω) to 2, 4, 8, 16 or 32. Since my speaker measured 4Ω, I set the meter to "W^4Ω" for RMS wattage at 4 ohms. I'll eventually put together a demo video of the unit, with setting up the unit for power output being the main objective.

I already had a Rockford Fosgate Punch 4020DSM on my test bench, so I decided it would be a good first test. The "old school" amp is rated at 20 watts x 4 @ 4 ohms. My test signal was a 100Hz tone and my power source was my Audio Authority Model 978 100A 13.8V power supply.

Here are my results:

76.65 watts RMS per channel (only 1 of the 4 channels driven) @ 4ohms, 100Hz @ 13.8v. Not bad for an amp rated at 20 watts per channel! The main difference to note is I can't measure THD, so Rockford's measurement (although still way underrated) was tested at 0.1% or less THD while mine could be up to 10%. They also usually test at 1000Hz, my test was limited to 100Hz (mainly to save my eardrums!). Once I get my resistors, I'll be able to test at various frequencies.

I also had a Rockford Fosgate Punch 30HD close by and knew it would be a good test. The amp is rated at 15 watts x 2 @ 4 ohms. I measured 24.75 watts RMS (from 1 channel) @ 4ohms, 100Hz @ 13.8v.

The HPS50 will connect to a PC via USB and capture real-time data as well. I attempted to test with my Windows 7 32-bit laptop and was unable to get the o'scope to communicate with the Velleman software. From reading the forms about this unit, many others are experiencing issues as well with Windows Vista. I'll attempt to install the software on a Windows XP computer to see if I can get the device communicating for real-time capture.

So far, the Velleman HPS50 is a fun tool! More tests coming soon...I'll have my dummy load setup complete and will begin testing the output power of my old school amps. Stay tuned in...

Not Really Old School - Orion HCCA 275g4 "Cheater Amp"

See my recent video review of the Orion HCCA 275g4 below. It is the last of the "Made In the USA" Orion amps, circa 1999-2000. This amp is a BEAST with 180A of fusing with output exceeding 2000w at 1ohm mono loads. 









Here are the published ratings at 12v:

• 4 ohms stereo = 75w/ch
• 2 ohms stereo = 150w/ch
• 1 ohm stereo = 300w/ch
• 1/2 ohm stereo = 600w/ch
• 4 ohms mono = 300w
• 2 ohms mono = 600w
• 1 ohm mono = 1200w

See the video below for more details about this monster amp:

Click the link if you prefer to see the video in HD (720 or 1080p):

http://www.youtube.com/watch?v=71UbM7N2VNU&hd=1

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Here are some images of Orion HCCA 275g4 (actually a 275R in a g4 shroud):

(Guts of a Monster!)

(Size vs. Iphone)

(Input Connectors / Gain Adjustments / X-Over Settings)

Excellent "Old School Showoff" Thread at DIYMA

One of my favorite forums for mobile audio, DIYMobileAudio.com has an excellent thread in their forums about Old School Gear. Grab your popcorn and soda and get ready for some interesting gear and reading:

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/36261-old-school-showoff-thread.html

Enjoy!

Old School Car Audio Magazines - Help!

I'm on an all out hunt for 1988-2005 Car Audio & Electronics and Car Stereo Review magazines. I had most of the issues back to the beginning of CA&E (1988), but tossed them during a move around 10 years ago. I know there must be some folks out there who have not made the mistake I did and still have these mags....right? 

I'm attempting to digitally archive all of these magazines for historical purposes. I've contacted CA&E and they are planning on archiving the issues themselves, but they also said this would take quite a while and was not a priority. I fully understand their stance as they must review and promote the current products to keep advertisers happy and such. As for me, I'm an old school car audio NUT and think it is VERY important to get these mags archived ASAP!

Anyone out there with some or all of these old mags want to be the first to donate their mags for a few months so I can get them scanned? Contact me at oldschoolstereo at gmail (.com) so we can work out the details. 

Let's keep the Old School alive!

Update 4/29/11:
I've received some feedback, even had some VERY generous people offer up their magazines (thank you!). I'm going to keep an ongoing list of the magazines I'm still missing to fill my collection. See the list below and let me know if you can help.




Here are the CA&E's I know I'm missing:

1988 - July (premiere issue), Aug, Sept, Nov
1989 - Mar, Apr, Sept
1990 - May, July, Sept
1992 - Dec
2003 - Jan, Apr, May, June
2004 - Jan, May, June
2006 - Feb, Mar, Nov
2007 - July
2008 - Dec (final issue)


Auto Sound & Security Magazines Needed:

1990 - Nov (I have Nov, but my issue is in BAD shape), Dec
1991 - Feb - Nov
1992 - Feb, Oct
1993 - Jan, May, June, July-Nov
1994 - All 12 issues
1995 - Jan-July, Aug-Oct
1996 - May
1997 - May
1998 - Sept, Dec
1999 - Mar, May
2000 - Sept, Nov
2001 - Oct
2002 - Mar, June, Aug-Dec (final issue = 12/02)

-BigD

New Site Design Coming Soon....

I apologize for the complete lack of design quality in oldschoolstereo.com! This is a VERY part-time gig for me and I'm going to get to a re-design as soon as possible.

Please send all comments/questions/pictures and more to oldschoolstereo at gmail. 

If you would like to contribute to oldschoolstereo, please use the "Donate" button below. Any amount would be greatly appreciated!

Old School Cheater Amps from the Early 90's

I recently did a video review comparing 4 Old School "cheater" amps. This is not designed cover ALL old school cheater amps, but the ones I happen to own.


Here are the amps in my overview:

1) Rockford Fosgate Punch 45HD - I consider this amp a "cheater" because it was underrated and would handle 1ohm loads even though it was not rated to do so. My Punch 45HD was birthed at 91.1 watts/ch into 2 ohm loads, although it was rated at 35 watts/ch into 2 ohms.

I purchased this amp in December 1991 and used it for years in 2 ohm mono configuration powering (2) 10" MTX Blue Thunder 4 ohm subs wired in parallel. No, I wasn't winning many SPL competitions with this setup, but it sounded surprisingly clean. I had a friend who used one of these amps powering all Rockford Series 1 speakers including; (2) 10's, (2) 6.5's, (2) 4's and (2) tweeters using a passive crossover network. Again, no SPL records broken here, but a clean and plenty loud setup with a "45 watt" amp.

Original retail price of the Punch 45HD was $279 USD, although shops in my area were known to push this price up to $299 or more as these amps were in high demand and relatively low supply in the early 90's.

2) Orion 225 HCCA (Digital Reference) - One of the most feared cheater amps of the early 90's. It was rated to handle loads as low as 1/2 ohm in stereo and 1 ohm mono. It was rated to output 200x2 or 400x1 into these loads. However, for competition's sake, it was rated at 25 watts x 2 into 4 ohms.

There were several versions of the 225 HCCA in the 1990's:

• 1st Generation would come to be known as the "Moon and Stars" version. This version required a separate bridging module from Orion to run it in mono.
• 2nd Generation (shown here) was the "Digital Reference" series. These amps, like the first Gen models, had a wiring harness for the speaker outputs and 8 gauge extended power and ground wires for power connection. This model had built-in bridging capability and an EQ button for boosting lows and highs while reducing mid-bass. See the video for the specifics.
• 3rd Generation "Competition Amp / X-over" model, A.K.A. "Pop Top" version has some notable differences from earlier models. For example, a built-in crossover via SLF-1 modules and speaker/power terminal plugs for easy wiring connections. The "Pop Top" name came from the top panel which could be removed to reveal the SLF-1 and/or by-pass modules.
• 4th Generation and later - known as the 225R, 225G4 and 225G5. I don't have many details about these amps other than I believe the 225R was the last model to be built in the USA. I'm also a little confused why the 225G4 was called the G4, when it was actually the 5th gen?

The Orion 225 HCCA originally retailed for around $600 USD. Yep, you could by 2 Punch 45HD's and still have some left over for wiring or other equipment...


3) Precision Power Pro Mos 25 - PPI's cheater amp rated at 25x2 into 4 ohms and designed to handle loads down to 1 ohm stereo or 2 ohms mono. The one I display in the video is an Art Series (white with silk-screened graphic), there were also versions in black.

The Pro Mos series was replaced in the mid 90's with the Pro Art series. Like the early Gen Orion HCCA models, the Pro Mos versions had wiring harness with plug and extended power and ground wires. My Pro Mos 25 didn't come with a wiring harness, so I had to source a re-manufactured one. Many people would just solder wires directly to the board, but I wanted to keep the amp in stock condition, especially due to the warranty seal being in tact and not wanting to break it!

I'm not certain of the original MSRP, but believe it was around $500 USD.

4) Phoenix Gold MPS-2240 - from PG's "Mobile Professional Series" line, the MPS-2240 was Phoenix Gold's least expensive MPS series amp. It was rated at 24x2 into 4 ohms and designed to handle 1/2 ohm stereo or 1 ohm mono loads where it was rated to put out 288 watts total. I don't have numbers to back it up, but this rating appears to be very conservative. I believe it was closer to 400 actual watts, maybe a little more.

As with the other cheater amps I've mentioned above, the MPS-2240 did not have any active crossover built-in. It did have nice terminal connections for speakers and power. Not to mention, the real beauty of this amp was the "guts". If you've never seen an MS or MPS series Phoenix Gold upside down and open, you've missed out! Watch the video to see what I mean!

According to the April 2006 version of Car Audio and Electronics "Directory", the MPS-2240 originally retailed for $529 USD. I recall these amps being difficult to find as Phoenix Gold had few if any authorized dealers in my area.

Again, this video is only an overview of each amp, not designed to be an extensive review. I may put each amp head to head in tests in the near future....so stay tuned!


Click the link if you prefer to see the video in HD (720 or 1080p):

Old School Cheater Amps in 1080p HD!

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Rockford Fosgate Punch 40i DSM Amp - Sound Quality Test - 1080p

Journey back to 1993...Rockford was to replace the VERY popular Punch 45 with a newer model and new design. How could they top the power, versatility and pure popularity of the Punch 45HD? Well, the entire Punch series saw a face lift. Gone were the HD series and out with the DSM series.

Here, I'm demonstrating a model with is unique in the DSM series. The Punch 40i DSM superseded the Punch 40 DSM and preceded the Punch 40ix DSM. It was released in the 1993-1994 time frame. Why did Rockford release only the Punch 40 as an "i" series? I'm not sure if this question has ever been answered. Maybe they thought the "entry level" DSM amp didn't need a crossover like the 60ix, 100ix and 200ix. It would become obvious if this was the case the decision was quickly changed and the Punch 40ix DSM would replace the Punch 40i.

Enough with the model number mumbo-jumbo, what's so special about the Punch 40i DSM? Well, as with most "oldschool" Rockford amplifiers, this one was VERY underrated. Yes, you may notice the 20x2 watt rating into 4 ohms and say, "why would anyone pay $300 for such an amp?" Well, there are several reasons, some referencing quality and durability. Most Rockford fans knew this amp would actually output 50-75 watts per/ch RMS into 4 ohms and around 200 watts bridged at 4 ohms mono. I don't have a birthsheet to prove this output but have seen some from these amps and these are the actual numbers.

In addition to providing more power than expected, these amps also exude top quality sonics. View my video below to experience the sonic quality of these amps. For best results, use high quality headphones. Enjoy the demo!




-BigDWiz