Tuesday, May 31, 2011

Old School Crunch Amp - CR100

Over the years, brand names are sometimes passed along from one owner to another. Remember Polaroid instant cameras? It was only a few years ago when you may have noticed DVD players branded with the Polaroid name. Well, unfortunately in most cases, the same passing along of name brands happens in the car audio world. I myself, dropped out of the car audio industry for nearly 10 years and when I returned, the brands I knew once as high quality, "Made in the USA" were well....not what they used to be. Some people may argue the Internet forced many car audio companies out of business and although I'm not sure it is 100% the case, I'm sure it had an affect on the industry.

Now, why must I bore you with history of car audio brand names? Well, because the next amplifier I'm going to talk about is the Crunch CR100 from approx. 1992. This amp was one of several made by Zed Audio, regarded by many as some of the better old school amps. Other brands, such as HiFonics and Autotek (among others), had models of amplifiers made by Zed Audio. If you happen to visit or search eBay, you'll notice the Zed-built amps usually go for a premium.

Unlike most modern car audio amps, the CR100 has a harness for speaker connections. I'm not sure why companies continued to use these harnesses instead of barrier strips into the mid 90's?. As most of you know, these harnesses are usually lost over the years or have been cut so many times, the wires are too short! Luckily, the Crunch CR100 I picked up had about 8 inches of speaker wire and even more power/ground wiring length. An immediate problem I had was identifying the speaker and remote turn on wiring colors. Some old school amps used red for remote turn on, others used blue...this amp has both! I opened the amp to reveal the guts and it appeared the blue was the turn on, however I wanted to be 100% sure, so I confided in one of my favorite resources - diymobileaudio.com. Within a few minutes, a member posted the wiring diagram and even a link to the owner's manual. Wow, this is great!

Zed Built Crunch CR100 Guts

The CR100 also allows plug-in modules for crossover/EQ and the one on this particular unit has an M30 module - selectable high/low pass crossover, adjustable frequency and bass boost at 45hz. At the time this amp was new to the market, Crunch offered several different modules so you could customize the amp to your liking.

Crunch CR100 with M30 Module

Now that I have the wiring guide, let's hook this baby up and see what she'll do! Since I was unsure if the amp would handle realistic 1ohm loads, I kept my testing loads to 2ohms minimum (2ohms stereo or 4ohms bridged mono). I connected up the amp to my Audio Authority 100A 13.8v power supply to guarantee I had plenty of juice for the test. The manual suggests a 15A fuse, yet strangely enough says it will consume 14A at full power into 4ohms...what about 2ohms? 15A sounds a little small to me. This amp just has to be more powerful than a Rockford Fosgate Punch 45HD....doesn't it?

Crunch CR100 Wiring Harness

If you read some of the enthusiast forums online, you'll hear rhetoric like "extremely underrated" and "highly underrated" when referring to these old school amps. As my test have shown, in some cases this is accurate, but in most cases the old school amps are only slightly underrated.

Here are the ratings obtained from the Owner's Manual:
  • 50w/ch @ 4ohms stereo
  • 90w/ch @ 2ohms stereo
  • 180w bridged @ 4ohms
And here are the official OldSchoolStereo.com test results for the Crunch CR100:
  • 61.93w/ch @ 4ohms stereo
  • 88.84w/ch @ 2ohms stereo
  • 198.8w bridged @ 4ohms
For additional information on my testing methods, see my previous post: Testing Output Power from Old School Amps. 

In addition to the power output tests, I hooked up the amp to a few speakers including a JL Audio 8W1 and a 12" Rockford Fosgate Punch classic sub. I set the CR100's M30 module to low pass at approx. 120Hz. The Crunch CR100 delivered all the power the JL 8W1 wanted and kept great control of the sub during testing. I demo'd several songs including; Jazz, Pop, Rock and Rap samples from my BigD demo CD. The nearly 200 watts at 4ohms mono was ample power to shake items on the wall of the OldSchoolStereo labs (aka "my garage"). Not only impressive from a 200 watt amp, but also from a 8" subwoofer!

The Rockford Fosgate PCH-812 subwoofer is 8 ohms, so it was only seeing around 100 watts. It is a mid-90's subwoofer and only needs 100-200 watts for ample output. Again, the Crunch CR100 provided clean, accurate power allowing the Punch sub to stand up to it's name!

I'm not sure how good the Crunch CR100 would prove pushing late model, heavy magnet, inefficient subwoofers...but it does a great job powering similar age (mid 90's) subwoofers and would be a great amp for a modest system. I guess one day I'll have to get some newer subwoofers to use testing these old school amps. Yep, I'll do that just as soon as the donations help pay for some...


Update: 6/26/11

I just located some Crunch amplifier ads from 1992 and 1993 Auto Sound & Security magazines. These ads show off the CR series amps and plug-in modules. With this information, I updated the post to note the amps were from the 1992 timeframe (not 1994) as originally stated. See a couple of the ads below:

Crunch Amp Ad from May 1993 - Auto Sound & Security

Crunch Amp Ad - November 1992 - Auto Sound & Security


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