"POWER", The Myths and Maths Series Part 3 - Amplifiers

Amplifiers.  Love them or leave them, they're one of the most abused and misrepresented links in the audio chain.

First some myths.  "Digital amplifiers are the best!".  There are digital amplifiers but they're not used in HiFi.  Digital amplifiers are used in telecommunications equipment to boost a digital signal on an analog format like coaxial cable to your home.  Even that isn't really a 'digital' amplifier, just an analog amplifier boosting a digital signal. (These also may be Class AB, Class D or even Tripath amplifiers)

The "D" in Class D does not stand for digital

Class D also known as a switching amp, is simply a variation of an amplifier in a long line of variations.  For example, Class A, Class B, Class C, Class D.  To keep track of different topologies, the EE community came up with a letter system.  If you invent a new way to amplify, you'll may just be granted the next letter which could be Q or W which I know doesn't sound as cool as D but it'd be a great addition to the community.  This letter system is helpful as some variations use combinations of topologies / formats.  Like Class AB which is by far the most popular.  Another example is Rockford's use of the combination of Class B and Class D amplifier topology, (BD).  My favorite is Class GH which has the sound quality of Class AB but the efficiency and low impedance features like Class D.  Class GH however is a proprietary technology and must be licensed if put into production.  Several brands have brought Class GH amps to market including Diamond Audio, Cerwin Vega Mobile and most recently new to the US, Vibe Audio.


Used and Abused

Amplifiers are the most mysterious item to most consumers.  The dials and controls mean nothing.  What the hell is impedance?  Why can't I bridge a mono amp?

The fact is that most of the people buying amplifiers do not know how to install them let alone how to set them.  Some manufacturers took extra steps to head this bad horse off at the pass.  In my work with Arthur Wilkes, he was in charge of testing at MTX.  His method was very practical and realistic.

At MTX, they used to test new equipment or factory samples by turning all the knobs to the right and letting it play full blast in a 'boom room', hooked up to real woofers, not resistors and seeing how long it lasts.  If it lasts a full day then it made it into production. (That's simplified of course).

Unfortunately, Mitek and it's brands in general are changing and it hasn't been for the benefit of it's customers.  It's now cheaper and easier just to replace a recently made amplifier than to fix it. This is now common for most all brands. There are of course exceptions, namely old school equipment that holds more value due to emotions than performance.



Today, nobody makes a bad amplifier.

Build houses cannot afford to make a dud, so they simply buy, "the best", and copy it.  That copy makes it's way to all the build houses.  There are exceptions of course and this is when the build house has good engineers on staff or on contract.  There are also still many brands here in the US that make tweaks to poorly executed products instead of new designs.  The problem with dealing with a build house that doesn't have integrity, know-how or just lost in translation. You can still have a great design but if it's stuffed with the wrong parts or substitutions have been made, it can lead to problems.

These build houses then figure a fail rate and compensate the buyer with more units for, 'free'.  So if an amplifier has a 50% fail rate and you order 1000 pcs.  The build house will send you around 1500 to 1650 pcs for the same price.  That seems to be the current solution to keep customers happy and and that means CHEAP boom.



Branded Cattle

Brands like Sundown have been using a higher quality / integrity build house like Chung Lam or Zenon in Korea as a means to compete in the ocean that is car audio.

(Chung Lam is most famous for being the build house for Orion and PPI in the late 90's and early 2000's before the brands were sold to DEI. DEI continued to use them until other, cheaper build houses were ramped up. If your Orion or PPI product says Designed or Engineered in USA, this was made by Chung Lam and assembled and tested here in Tempe, AZ)

Most larger companies that are serious and get good quality in China use a company called Boss.
It's not this Boss, but if you can pay, you'll get perfection.  The trick is will your customers agree with your $100k decision?

Several brands have followed in the same direction as Jacob.  Jake wasn't the first to use Zenon but he now has their ear and Sundown leads the changes in the cottage brand industry.  Sundown has created many of it's own, "me too", brands with many making exact copies with exception to branding.  Some include DC Sound Labs and Skar Audio leading the way.  Others come from another lineage created by Mark and Scott of RE Audio aka Resonant Engineering.  With Scott selling his share in RE to then go on and start Fi Car Audio and now building for brands that want to tout, Made in America, like Ascendant Audio and SSA.  This is the reason why most brands look and function the same, they ARE the same.

Some brands use a combination of off the shelf and new engineering like Nick Lemons at Stereo Integrity and Obsidian Audio.  Running Obsidian allowed him to use those funds to engineer the ultimate in thin subwoofers the SI BMIV.  Obsidian basically made a fancier version of the Sundown SA series. (Nick and Jacob also ran out of the same facility and shared in shipments.  Making subs and money with friends is the ultimate.)

For me it boils down to value or Dollar per DB.  We offer many styles and formats and many have a full 1yr warranty against anything.  Even if you screw it up during the install.

If you buy new, you may want to look at new / upstart brands like Twisted Sounds for amps or DS18. Both use mainstream construction channels from Asia but are new to market so they compete on price and quality.  They are still, "me too", brands but are a better value for now.

Later like we saw from the Audiobahn group, they may start dulling down products by leveraging your emotions about the brand. Brands like Rockford do this about every 3 years.  Last year's P3 is now this year's T1.  Some go the other way as well to make it look like they're improving.  Either way it's always shifting and changing and it's tough to lock down solid information.  I feel like this every time I buy paper towels.  There's a sale but that one's a better value all the time and I really like Select-a-size.... etc.  Sometimes it's just chrome and led's to get that emotion about a brand or a paint scheme like the old PPI Art series amps.

DS18 has already started doing this by making knock-offs of Sundown and other brands.  Twisted Sounds products will remain strong and should start to enter the woofer arena.  Travis is helping the cause by also diversifying into other aspects of the goal of loud bass like using lithium batteries rather than lead-acid.


New Sprouts of Innovation - Good Seeds and Bad Seeds


New technologies are being developed every day.  In the audio industry, this race is quite fierce.  Some brands have learned that to survive and prosper, you can't use, "off the shelf", or "open tooling", products forever.

As mentioned, many of you know about Travis Young of TS and his work to produce LiOn batteries for audio use.  Look for him to start producing solar products for DIY'ers that need energy storage. Some companies will actually land a high volume contract to pay for expensive tooling on the other end of their brand or another brand under their umbrella.  We saw Rockford Corp do this when they acquired Lightning Audio.  Larry and Scott sold Lightning to Rockford for a nice chunk.  Scott then got to retire with is new bride and Larry when and bought Cerwin Vega Mobile and Diamond Audio.  Larry helped form a brand called Fierce that you may have seen in Best Buy.

Kicker can now be found at WalMart.  Don't get mad, this is wonderful.  Kicker will displace other brands that are moving away from car audio like we saw Boston Acoustics do.  Look for Sony to be leaving as well.  Kicker will now fold that $50k to $1M a month back into the brand to tool up some really cool gear.  Someone has to pay for pimped out speedboats and coked whores, (your mom).

Not all money is well spent.  DC Audio shelled out tooling dollars for new frames like their new 8" sub the M38.  However it's still a copy of Sundown products as for performance.  So what are you buying?

For me it's always been about performance.  Choosing an amplifier for me now is about price / value.  If you can give up the need to show off your system and have confidence in your know-how and execution, you can have a fantastic system for less and that's what we've been doing at Robot Underground for over 20 years.

I love showing off a system that uses Pyramid brand components after people hear it.  One of my mentors, Mike Q. told me to, "bench it before you bitch at it".

Be aware of when a brand touts a patent.  Many times the patent will be an ornamental type, meaning it has to do with the product look, not function.  Other times like in the case of JL audio and their, (at the time), new, fancy tiny class D amplifiers.  It was another company's patent.

For the most part, make sure if you can, that the amp has a warranty.  Make sure you know what the warranty covers.  Most DO NOT cover abuse / misuse, so educate yourself on how and what to do.  Make sure you understand the shipping policies.  The norm is for YOU to pay return shipping to the seller.  Then the seller determines whether or not it's abuse or defect.  The SELLER then has the CHOICE on whether to fix, replace or just no honor the warranty.  If it is covered, SELLER pays return shipping.  Even if it's not covered, a good seller will still pay return shipping.  For us though, we buy dead subs so we often will give a 'core credit' for a dead sub towards a new one.  We also have a Forever Upgrade policy.  So if your item is covered under warranty, we'll give you full credit for it towards an upgrade to something that's more to your liking or application.


"Scotty!  We need more power!"

One of the most debated myths about amplifiers is that you can blow your sub by not having enough power.  This is misleading.  Subs don't catch on fire by sending small signals to them.  The idea behind the myth is that if you are pushing your amp too hard, (clipping), you send a distorted and usually a signal that's double the power to the speaker.

The sine wave is your friend.  If your amp has too much input, or the output is too close to a short, the amplifier will distort or 'clip'.

If you have say, a VR3 200wrms amplifier that you can find for very cheap and you turn it up too loud, aka - clip the input of the amplifier.  That perfect sine wave you're after turns into a square wave.  Square waves aren't usually the best sounding so USE COMMON SENSE and if you hear distortion or you find that if you turn it up past 20 and it doesn't get any louder, TURN IT DOWN!

20 in this case, is the maximum loudness you'll be getting.  A fully clipped square wave contains more energy than a sine wave.  This higher energy level along with being square pushes the coil out of the gap suddenly.  The more time that the coil spends out of the gap, the hotter it gets.  It's basically a portable toaster oven.  This also occurs when you push the subwoofer to the ends of it's excursion.

Some subwoofers have limiters build into them to prevent this. (Both JBL and Boston Acoustics at one time used a shorted coil of wire, above the voice coil, on the former to keep the coil assembly from traveling too far.)  Most do not so it's up to you to use common sense.  If you want your subs to go to 11, you'll need at least a bigger, more powerful amp and speakers that can handle that power.

Running a clipped signal to the amplifier also causes the amp to draw more power than normal.  This can cause anything from killing batteries and alternators to melting wire.  Remember that your system is only as strong as it's weakest link.  I would recommend a shop or brand but most all of them always have an agenda at the end of their explanation and that's a terrible abuse of the trust you just built with that client.


Lies, Lies, Lies

I wrote about power ratings on subwoofers in the last issue and they don't get any better with amplifiers.  Most all, including mainstream brands like Alpine and Pioneer post a completely imaginary power rating on their products.  I saw an Alpine Type R subwoofer rated for 3000 watts!? Even the 1000wrms rating is a lie.  The question is, "How much of a lie?"

For years bass heads have shunned brands that over rate their amplifiers.  Some common culprits include any brand from the Pyramid Group, (Pyramid, Legacy, Pyle, Lanzar).  Others include those from the Boss Group, (Boss, SSL / Sound Storm Labs, Planet Audio).  Also included are 'higher' end brand groups like Epsilon Group, (Precision Power, Power Acoustik, SPL, Soundstream, Farenheit and now shelved, Kole Audio brand).  Don't forget the crazy German at American Hifi, (Nitro, Rockwood, Volfenhag and their flagship brand, Performance Teknique.

All of these brands then have 2-5 lines of amps, PER BRAND!  That's a lot of skews and amps to sort through.  These brands, or any brand that posts a peak rating is taking advantage of the end user's ignorance.  I've had more than a few clients pick an inferior product because of the peak rating even after I did my best to present a clearer picture.  The good part for you, is that NONE OF THESE AMPS ARE BAD!!!!  None of these brands even do engineering work.

They're all designer brands.. That makes them sound fancy now.  But that's what a designer brand is, they take something off the shelf.  Meaning they use parts or a whole product that's already made by the factory.  Then they bling it up or package it in a way that makes it seem more in line with their target market.  This is where the market is now to stay in line with customer expectations of affordable boom that looks cool and performs well.



None of these brands are "bad", or "cheap", or poorly constructed.  They're made in the same factories that many of your favorite, "name brands", are made.  Many times they are even the same amplifier with small changes to color or screen printing.

I would show you what used to be a great site called Ampguts (can't even show archived pages), but Anthony, "Ant", Collova bought the site as part of the ROE forum, (Realm of Excursion), and now asks for a FEE to look and compare the boards of amplifiers that users submitted.  This may be unfortunate for now, but that's why I started AudioGuts.org which will ALWAYS be free and open for discussion by everyone.

Some examples were a local retailer called, RAS or Rabadi & Sons bought the Majestic brand and created Niche Audio.  Both use THE SAME class D amps used in several Treo Engineering amplifiers.  Funny that a brand with the word, "Engineering" in it would use off the shelf amplifiers.  Also, please update your website at least every 10 years and put some pics next to each series.  I know, I shouldn't criticize a big brand like Treo.  I guess I'm not awesome enough to own expensive stuff like that so I can show everybody I'm cool and successful.




"I want to hear solutions, not problems!"

To sum it up, here are some tips to help you navigate the growing field of electronics.  A quick way to tell how powerful and amp is:



1. Look at the fuse rating and add a zero. (Amperes x Voltage = Power in watts)

Using a conservative version of Ohm's Law we're simply multiplying the maximum current rating in amperes by voltage to get power in watts.(We're using 10 volts in this case which makes the math easy and provides a more, real world, power rating for the amp.  The amp has losses and inefficiencies that are impossible to measure without a test bench.  Remember this is a primafacie example for shopping for amps.

This is a quick way to find out the real rating on an amp.  We love the Boss / SSL tiny class D amp.  It's very compact, has great controls and features like a volume knob and high level input.  It's NOT however 3000w.  The fuse rating is accurate at 40A.  If you add a zero to 40, you get 400 which it does a solid 400wrms and is 1 ohm stable.

Exceptions: We have found Lanzar making an amp with dual 30A fuses but they're wired in series which makes it a 300wrms amplifier or better.

Also some makers just say, "Flux it!" and put an oversized fuse on it like the BAMF 5500D from Power Acoustik. (You can tell just by looking at the power supply transformers that there's no way each one does 1000wrms.  It used to have 3 450 transformers but they changed the design to two 650w transformers.)

Which leads to the question I usually get after that, "How can I get a better idea of what an amp can do without testing it?"



2. AudioGuts.org

Audio Guts dot ORG is a free forum I'm setting up to allow ALL audio item information to be shared with others in the community.

One thing I've been doing is a simple inventory on the 3 dozen or so amps that pass through here each month.
    A. I take a few quick pics of the amp and it's board. (All sides if possible)
    B. I write down the fuse rating
    C. I write down the number and values of the capacitors the input section of the power supply.
    D. I write down the number and values of the caps in the output section of  the power supply.
    E. I write down the number and model of the devices in the power supply
    F. I write down the number and model of the devices in the output section

Using these numbers you can get a better idea of what the amp can do and what the engineer was thinking when they created this amp.

For example:
The MTX MTA225 is a great old school amp.  Made by PPI and uses 6x 2N6488 & 6x 2N6491 in the output.  With 8x 5N05E in the power supply.

You can look up the spec sheet on the output devices and you'll see that the total dissipation per device is 75 watts.  So 75 watts x 12 = 900w.  But the amp is only as powerful as it's weakest link.  The power supply devices are... Well, I don't know because I wrote down the wrong part number.  It's most likely in the RFP50N06 family which is 50A version of the device.  Very old, late 80's and used on several PPI and Orion designs.  Which makes sense because each device is good for 131 watts.  That would make the power supply capable of 1048 watts. (Remember too, that some devices are rated MORE than their package can handle.  This package type is called TO-220 and is only good for around 70W.  That's why some makers move to larger package types for the same device like the TO-247 or TO-3  Overall due to losses the amp should do around 650 to 800wrms right?  Nope.  Most amps when engineered, usually aim to use only half the rated power of each device.  So this ends up making it a solid 400wrms amp.  The idea though is that you can now compare to other brands to see what you're getting.

There are of course exceptions like the drag race here on Oldschoolcarstereo.com.
There seems to have been a blow out on the MTX amp.

Remember that on older amps, the caps dry out and aren't able to store the full electric charge.  That's why older amps should be serviced and gone through / inspected by someone familiar with electronics repair.  Update the caps and if it's got dead devices, ALL devices should be changed on that section of the amp so that they match.  Newer devices are much more powerful and have a lower resistance.  If you change out just one device, that device will carry more current and blow.  So in a small amp like the 225, a good tech will change out all the devices and update it.  The weak link in the chain will then fall to the caps and transformer which can of course be upgraded as well but then you basically have a much bigger amp in the same size heat sink and then that can lead to problems as well.

MTX actually toted this amp as being .5 ohm stable, (for a limited time, like for competition).   Though I'm sure people abused it and ran it .5 ohm per channel or even lower and claimed it as a superior amp because it didn't go up in smoke right away.  PPI was at the same time building a version as the ProMOS25 and of course at 2x the price because it was far superior and many fans believe it to be true.

AudioGuts will also cover ALL aspects of products including how to repair, work arounds, schematics, hacks, possible conversions and even down to the screw size thread and where to find the best price on them whether it's a personal or commercial source.


That's a wrap!

The take away from this article is that there is more, much more there than what the sales person is telling you.... and that's ok.

One reason I started Robot Underground was because I wanted to learn and was tired of being lied to.
Sales people do not get paid to teach.  They get paid to sell.  Be aware of that when you go into a retail store.  I used to hold this against them but it's not their fault.  Retail stores paint themselves into a corner by having a 'good', visible location.  This is more expensive than a warehouse or as many of you remember me working from home.  They also have a staff and they want to be paid for just being there, even if they're not doing anything and that costs money.  Insurance and utilities are even more expensive too because they know you're there to make money and will charge you more.

In the end, most shops follow the same patterns of bad behaviors.  Up-selling when it's not needed.  Charging too much for an item to begin with.  Charging you for 12ga OFC when they really gave you 18ga aluminum wire.  Charging you for a custom box when they buy it pre-made for super cheap.  In the end, just lying to you and taking advantage because you don't know any different.

If you did know different, you wouldn't be there in the first place so it's kind of your fault too.  No need to blame.  Just chalk it up to a learning experience and do something different. Just don't be the person that goes $50k in the hole for an education, just to end up working at Starbucks.

This day and age is much better than it was yesterday.  I learned what I know from car audio magazines and literature.  In fact, once I figured out how to use that information, I became one of the better students in my military training.  Without that information I would have ended up in a grunt job.

Computers and the interwebs allow you to learn at your own pace.  You can check and recheck multiple sources to make sure the information you're getting is true.

Finally, take responsibility for your education and test these lessons in your own space and time.  Experience is what really makes you a pro at something and that's why we teach the way we do.

See you next time.  We'll tackle energy sources as well as batteries vs caps with a revisit to wire.  After that we'll address audio addiction and hoarding.



Patrick Chandler
Co-Founder of The Robot Underground.
robotunderground@yahoo.com