One other note: For some designs, empty space can also put components with high interference like transformers away from critical areas of the device to avoid noise, and in some cases empty space helps isolate components from excessive heat.
Another reason for an amp case to be large is to do with ventilation and air flow. Many components get hot and keeping the components around them cool will extend their life.
I remember this in the old Sunn Coliseum bass amp; there were warning not to thouch the heat sinks or power output transistors.This is not so much of an issue in class D amps.
17" wide audio equipment became a "standard" so it could fit, either on a shelve or with front mounting "ears" in a standard 19" rack. The 19" rack format with rack-units "RU's" of 1.75 inches was established as a standard by AT&T in 1922. The 19" rack format has remained constant while the equipment mounted in it has changed over the decades. The 19" rack is widely used throughout the telecommunication, computing, audio, video, entertainment and industries.
@@TheElverma I like the story that relay racks originated in railroad switching yard control systems. Wiki says there's no evidence they were standardized before 1922 which is not surprising. AT+T needed lots of relays to connect phone calls and the railroads already had the hardware, using racks of relays to remotely control switches in rail yards. AT+T didn't invent it, they just standardized it.
Marketing is critical to sales. I see something very similar in the tire industry. Ever wonder why a high performance tire may cost four, even five times as much as a standard one? The tire dimensions, tooling, labor force and most parts are the same. Yes, some ingredients are more expensive. But definitely enough to justify such a high cost. The reason why high performance tires cost so much is because most people believe they should. Marketing.
Never new why products were sized the way they were. Thanks for the explanation. I remember as a teenager going into audio salons and drooling over the components in the 70's. Audio racks were really cool.
If you want to see empty inside. Check out mini stereos from the 90s, the all in one units with tape, CD and tuner. There’s a few circuit boards and the rest is completely empty.
Our Knock Knock test we did was to do with throwing a newly finished piece of equipment down several flights of stairs (test sample and fully ready for delivery) just to see how it would withstand postage! Speaks volumes about our UK postage delivery services :)
The 19” was standardized by the EIAJ if I’m not mistaken. Most of my equipment is rack mount. Only real drawback is you have to have supports at the rear of the equipment and a lot of manufacturers don’t supply rack mount “ears” for their equipment.
When mt dad transitioned from a music centre to components in the mid 70s he did a fair bit of research before reaching his final choice. He said that the thinner a unit was the less substantial the components inside were. He also directly attributed weight to quality. That has definitely rubbed off onto me I'm afraid.
Standard case sizes make installers happy. "Heavy" has always been a good seller of electronics because it was unavoidable for most of design history. Put in one heavy design element and everything else has to made heavy to compensate. "Broadcast" turntables, Marantz flywheel tuning, and iron core output transformers, come to mind of designs that set trends. Until Class D amplifiers came along, I judged an amplifier by its physical weight. There was a fad in the 1960's when hi-fi components were installed in cutouts in the walls.
I got the big speakers hooked at the moment: You could hear the weight of the smaller unit as you placed it back on the table. It had that 'knock knock' approval sound.
Yep, true on 19" rack. Even my standard ole Onkyo Surround receiver measures just a tad over 17" across. I also use a steel rack too for other gear. If I fabricated adapter "ears" for the receiver, it would probably fit in the rack!
To some extent , Transistors still have to deliver both Voltage and Current enough to drive the speakers and there is a Physical limit to the size of them to be able to deliver , after all byproduct is heat and it take a certain amount of size to dispose this combined with a good big heatsink too . Even smaller you make the component even less power they can handle , it is physics . Big heavy duty amplifiers with big strong transistors and heatsinks combined with a power supply that can deliver the voltage required with enough ampere is of course less prone to clipping and thus produce much more clean signal at high output compared with a typically small system with socalled same WATT number . A 300 watt amplifier with small transistors and little powersupply that cant deliver enough ampere will of course be clipping and most often can NEVER reach the socalled 300 watt in more than a few micro seconds . Where an Amplifier there is constructed with transistors big enough to handle the load and a power supply that can deliver more than just a few ampere can run this power continurly thus at same measurement methods it of course spit out much much more Watt in the same micro second ,, but the 300 watt is constant and to do this you cant just squice in some small micro component and call it a day . ( If that wasnt true then nobody would still produce those big heavy amplifiers ) Those small class D with switch mode is a HYPE and as we all know a Hype is SELLING and compare this with very CHEAP constuction / components and you have a BIG PROFIT ..
@@kennethsrensen7706 totally agree with you, no replacement for displacement (speaking in car terms) Also manufacturers need to stop running components in equipment to their limits most of the time, no room for error. If it is cooking hot at idle then it's not going to take much to push it over the edge and go poof!
@@kennethsrensen7706 And yet my 5kg class D power amp in my living room utterly destroyed the 25kg Arcam amp rated at a true 200watts per channel. Not even close. I sold the Arcam within days. Truly feeble sounding next to the Class D
When I bought my first ‘proper’ amplifier (Arcam Alpha 10) about 22 years ago it definitely passed the knock-knock test. It felt like I was picking up a block of lead and it’s built like a brick. The heat it generated when powering the front mains on my home cinema setup was significant so it got extra room in my rack. It has a large ‘air-space’ on one side, presumably in part to ventilate that heat. Today, it’s semi-retired, replaced by a Denon AVR - which passes KK test - but I could never let it go. Such a lovely piece of kit. I just want to find another use for it. Suggestions welcome. By comparison, my 40 year-old Denon CD player has almost twice the internal volume, mostly air, and feels plasticky. Fails KK test - plays beautifully though.
The Arcam alpha 10 was a wonderful amp in its time. Handily beats far more expensive amps like bryston B60 & Accuphase 203. To me of cos. YMMV. Later Arcams such as A85 & A38 were also very good value for $$. Just make sure the gain in these amps are set to the max otherwise they will sound weak & lacking in dynamics.
The Earliest recollection of Exactly that Same Test that I Believe Started it: The Two Stereo Companies were Scott & Fisher !! The event happened prior to me working for one of them in 1972.
This is why I love my Bang & Olsen bowmaster 6500 with penta 3 speakers the amplifiers built into them and sound that you have never heard if you've ever heard these speakers before. I have my set of pentas that I got over 20 years ago that were built in 89 and they still run a perfectly today as it did back then. But then again you expect that kind of quality from a manufacturer like Bang & Olsen. When I first heard Pink Floyd on my new system that I got back in the late '90s it sounded like I was hearing Pink Floyd for the first time. Notes and sounds that I never heard before we're coming out of my speakers that made it sound that much better. These speakers never crack and you just turn them up louder and louder and the louder you go the more insane you get. They penetrate through walls like they aren't even there. The further you are away from it the better it sounds it seems. But even turn down to two you can have a hard time hearing if you're on the phone with somebody. I believe it goes up to 60 but I've never had it above about a 56 because it's just too loud. I don't believe they ever made anything 17x19. They always did things their own way and it shows with her quality. Did I mention I had to spend $5,000 to buy the last set of Penta speakers sold in United States... Back in their Mission Valley San Diego California store. Which was right across the hall from a Bose stereo store which if you walked into both of them you could unmistakably hear the quality of the Bang side and the Bose sounded like an empty hollow tube
The knock knock test, that's a new one, never thought of doing that to an amp. My favourite is to lift one corner and see if the chassis flexes, i.e. one foot of the table, the other three still on the table is a fail.
in the 90's I worked on CD players and VCRs. One top of the line denon CD player that crossed my bench was cheap plastic inside but it had a 1/8" thick steel plate spot welded to the bottom cover plate.
Nearly all "professional" sound equipment is based on standard dimensions and usual is listed as per how many Rack Units or RU's it is. So you will see 1RU, 2RU etc. They also have "wings" to allow them to be mounted into the carrying rack. A lot of consumer audio still follow the same dimensions.
Both my reciver and my stereo/power amp (dedicated pwr amp inputs) are stuffed full😝 The stereo amp even has two power supplies since it's built as a dual mono.
A lot of electronics have gone from discrete components to semiconductor modules. I think these came out of car audio but I’ve seen a few home audio-video receivers have them too. Just a big black chip that is a 60 watt amplifier. Line level in, 24 Vdc and outputs to the speakers. Designed to be mounted on a heat sink. Smaller than a car key fob. This takes the place of a much bigger circuit board.
Years ago, my company made the tools to produce a plastic housing for a Pioneer power amp. The housing had some weird features on the inside. I questioned what they were being used for. The answer was that they held section of rebar. The heavy metal rods used to strengthen concrete structures. They were using rebar to add weight to the power amp. Light weight amps didn't sell as customers expected a power amp to be heavy to really produce high power output. Total BS.
Funny you mention the air / empty space. I have a Phase Linear 400 and even with the reduced depth as compared to a Pioneer Spec series, there's more empty real estate inside than the Pioneer. That Spec amp is chock full to the brim. BTW, they both pass the KK test and the weight test. As one friend said, these things are like a window AC unit with handles.... and a power cord to match.
I took apart a Sony phone to fix a broken wire only to find it had a piece of cast iron in the handset. Took it out, felt cheap as hell. Put it back in, yup, better quality feel.
A full-featured amplifier could fit on a circuit board the size of a 3 X 5 card. It just won't have much amplification. Powering woofers etc. creates heat.
I know no one that listened to great sounding gear, was ready to buy, but chose not to do so based on a "knock knock" test. There are people that buy without listening. So perhaps they do the "knock knock" test? Paul, your Aesthetix Calypso has a light cover on it. And you have praised that pre-amp. It changed your mind, such that you no longer connect your CD player directly to your amps. I am not buying that someone that auditioned that that pre-amp would decline to purchase it, due to its light-weight cover. In a department store, that seems reasonable. As far as I know, PS Audio gear is not sold in department stores.
A lot of amplifiers today use a switch mode power supply negating the need for a large heavy power transformer, SMD components that take up much less space, and much more efficient Class D amplifier modules negating the need for bulky heatsinks. In fact, PS Audio's own Stellar S300 is a perfect example, with 140 watts per channel, weighing just 13 pounds, and with lots of extra space inside the chassis.
I use the "Knock Knock Test" on speakers, but not only the top, the middle of the back, the sides, etc. You don't want the ones that sound like a wooden shipping crate. You want the ones that sound like a block of cement. The ones the drivers won't thump and make sound like the box are the ones you want. Yes they are heavy and expansive to ship. Try it next time in your local high end audio or home theater store.
I recall seeing some impressive looking car audio amps back in the early 90s. Manufacturers were all trying to out-impress each other. I saw a few of the cheaper ones opened up and was just shocked at how little was inside and how crappy the components in it were.
Have you seen Derek BigD (Williston Audio Labs) on RU-vid, where he tested one of those "reverse cheater amps" on the amp dyno? I think it was a Pyramid model from the early 90's or late 80's. Big looking amp, but when it got opened up, the inside components were a joke. A tiny circuit board on one side, with a bunch of long wires soldered on to reach the inputs and the dials on the other side
The SET monos I build - have a very low parts count in a small box. The box is 5 mill steel. They feel weighted. They sound right when driving the right drivers.
The other thing that "makes for more empty space" is that components are way smaller than they use to be. For example, tuner sections in stereo receivers are no where near as big as they use to be. Also, most amplifiers don't use the old TO3 transistor banks anymore. They were big and required BIG heatsinks.
@@dizzywow ... yes, but in those days you needed size just for the heat handling ability. Basically the same reason a large radiator in your home can deliver more heat to the air.
Really awesome amp right there very nice Paul. I have a Nakamichi PA-7, What? lol. Yes they are, becoming smaller because a lot are implementing switcher amps with caps instead of transistors and massive transformers. Less heat, no noise and the winning part: cheap to make. Though I’ll take my transformers and noise any day over a class ‘D’ switcher. Just not a true ‘amp’, no soul and ‘sim’ sounding. Great video, long live two channel.
@@peterlarkin762 Hey Peter, outstanding for its age. Very dynamic amp, (some have said ‘veiled’, but that’s just slander imo and using Audioquest Evergreen for signal) love the older stuff that’s built like real equipment. Nice to have something Mr. Pass worked on, what a talent. It was part of Nakamichis flagship line back in 1988, a good friend here in Daytona that owns ‘Stereo Types’ was upgrading in 2000, and wanted 3k for the amp, pre and tuner. I gave him the “So is that the price for your FRIEND” line, and he looks at me and says: “Go get me 2k cash before I change my mind” with a smile lol. Not a bad day at all at that point, pretty righteous for a decent system. Thanks for your interest Peter, enjoy sir.
Thanks Randy, man! Think it's an amp on my 'see it, buy it' list now. Honestly, discrete power amp circuitry has not evolved a huge amount since that was produced. And it's such a beautiful chassis. Rare here in Ireland. A PA5 would suffice. You got a seriously good deal for the stack! I've also been researching the amazing Nakamichi Dragon CT turntable and it's self centering mechanism. Ingenious. Best wishes and peace. Peter.
How many Class D have you heard?? I've been listening to amps for years (35 +) class A class A/B as that was all that was available I'm currently using a tube preamp with a class D power amp (600 wpc). It utterly destroys any of the traditional Amps I've had ( creek, Arcam naim Denon etc etc) I'll never buy another class A classA/B. Why do I feel like this ? Why does this combo sound so superior to anything else I've ever owned??
As an audio guy, I am continuously frustrated with the way that people “hear with their eyes”. I deal with it on every level and in every situation. I learned from doing corporate work that the sound is only important when there’s an obvious sonic problem that can be easily heard by a layman. At all the other times, looks and general appearances matter more than anything.
The knock knock test reminds me of the computer industry in the late 70s to early 80s, where computers had to be big cabinets full of equipment, but the industry was starting to use desk top systems. The owner of the computer company I worked for said we don't make furniture, and missed the boat and the industry outran his tiny mindset, and he went out of business.
I have 3 pieces of InterM 500 amplifiers. And they are convection cooled! And there is space inside. And the bottom and the top plate is open. Plenty of slot's on the sheet! Then I have an InterM 1000. There is no place what'soewer. But it's cooled with fans!!
Oh yes that’s why i absolutely LOVE brit amps. The small form factor & high performance has always been very appealing to me. Recall my friend’s puny naim 72/180/hi cap killing many other huge amps in the control, dynamics, speed, slam & musicality stakes. The brits just do it better when it comes to elusive things like toe tapping & head nodding. They were simply far more involving. The brits call it PRAT! And up till now, no one does it better other than the brits.
I recently bought a tuner and true to form I had to have a look. Turns out there's just a fat chip on the little front panel PCB, a few tact switches, an LCD AND NOTHING ELSE! So where's the tuner? It's all in software and the entire chassis is empty save for a tiny little SMPS at the rear by the massive AC inlet. And it works great as tuners go. Why have rows of LC stuff when you don't have to?
Topping and others are turning this 17" thing on its head... Can fit separates from Topping (DAC , Preamp and Amp) all inside of a 17" 2U case with arguably better specs
The last Topping amp I bought sounded worse than the Dayton Audio amp that used the same chip. It didn't sound too bad, but not worth the extra $ over the cheaper one. More of a complement to the parts express folks than anything else I guess. I think both models are now discontinued.
You would think that by adding space in between components. That it would help reduce crosstalk. If thats the word im looking for. One reason why separates and external power supplies can have lower noise floor. Some people may call it fog.
👍 Even though he did not mention class D amp, we can imagine the class D amp in the standard chassis looks so "empty". Chinese manufacturers make very compact class D amplifiers like SA-98E ignoring the standard 17"(430mm) width, with an external AC/DC adapter.
I do the same with acoustic guitars, rap with your middle finger a few inches from the edge of the bridge it should have a nice woody tone with a long decay, if it has a cardboardy sound with a fast decay it will sound bad.I know, why not just play it, some old guitars may not have their strings on or the strings are so old you cant make a good judgement on the sound.
I purchased, online Ebay, a duel 8" speaker with duel horn tweeters Karaoke bluetooth and aux. Typical setup. It sounded flat and horrible. After opening it up, speakers had tape shocks no foam rubber, and NO tweeters in the molded horns at all. I was shocked. It needs an amp but I haven't learned how to build one to add on. Yet. Lol
Standard sizes of cases started to get too big for standard components due to miniaturisation. When I purchased my first stereo set in the 80s, it was the standard 19“ size. The rack had to be that wide because of the vinyl record player on top of it. But then CDs were about to take over, and there wasn’t any need for big cases any longer. So Sony decided to produce smaller sets. But they still had to provide stereo sets of the ‚classic' size. What did they do? Produce the smaller form factor PCBs, mount them into the big cases and leave half the case empty.
Yeah mostly empty space because of highly integrated circiuts. However, even higher powered audio amp chipsets should be a little more substantial just to handle the power passing through through and probably heat sinks to dissipate heat energy that doesn't come out as sound energy.
Once I looked inside a musical fidelity amp, and that one had a transformer in one corner, a green circuit board in another and the rest was just air and heatsink on the outer edges.
You didn't mention this, but it is important to remember that in order to maximize audio performance and minimize noise and distortion, certain of the components must be kept physically distinct and as far as practical from the other. Any component in the signal path can receive interference from a component in the power supply path - so a careful audio engineer designing a new device has to make isolation of the signal and power supply paths an extremely high priority. Many times the best way to accomplish this is just with a little extra distance between components.
Wasn't there also that old classic theory of trying to reduce the number of parts or components to try and reduce any artifice or sonic interference in the signal path too?
It is actually in reverse. You will still find the better and more expensive hardware bragging about discrete components instead of ICs. Thermal noise crosstalk when multiple devices are on one silicon! Point to point wiring over circuit boards. Less capacitance and path crosstalk....
The knock knock test really made me laugh…..i am also from singapore & i recall in the 70s & 80s, many ignorant audiophiles back then judge an amplifier by its weight. The heavier they weigh, the better. I fondly remember how a group of older audiophiles went totally nuts when my puny 3.5kg Creek 4140 integrated amp massacred a humongous 50kg pioneer receiver in terms of bass control, dynamics & sound quality. They couldn’t believe what they heard. Scratched their heads real hard. 2 days later i repeated the same trick with another puny amp in the form of Mission Cyrus 2. Today i own LFD LE 3 which is also puny & has plenty of underutilised real estate inside. But i far prefer its sound to many 30 to 50kg behemoths. Pick your poison!
A lot of old Amps need a lot of cooling special the first class a/b Amps. The big weight come from cooling heatplate and the travo ring . After a/b with Mosfet the amp las weight and cooling need IT. Later airflow by a fan and again lower weight . After dat class-d amp what do not really need a lot of cooling. Its how a/b VS d amp works. A/b Amps have always power on the speaker. A class-d and somtimes digital d amp . Can set the power of to your speakers. No sound means no Heat . Than real old class a Amps. Well that have to Heat u for a good sound. Its Just what the type amp it is.
Coming from the semiconductor field, electronics have become more efficient, and therefore smaller, while keeping the shell the same, so over the years its gonna get worse. I remember back in 1986 while stationed in NY i bought my first CD radio built by JVC, it was ~$100 with detachable speakers, and "chock full of parts, It was a solid Japanese radio, some one else bought a Koss or something like it but it was Chinese. When he opened his up and found a few electronic boards with metal plates giving the false impression of a quality radio, but was junk that caused more interference than it was worth.
Another reason for space is that electrical components got smaller and more powerful. Think back to the Crown DC 300. Large E-frame transformer, large low-density capacitors, TO3 transistors, etc. Transformers are (for the most part) smaller toroidal transformer, Higher density caps, (switch-mode supply in some lower grade amps) TO3P or TO220 transistors, etc.
Also components have gotten smaller. Back in the day caps were a lot bigger actually everything was a lot bigger so it made it look like it was full. TDA chips are basically a amplifier in itself with minimal components. So now we have Palm size amplifiers that are pretty loud. 😁 In my opinion minimal components are good because the sound doesn't have to travel as far to get to the output. It creates a cleaner sound the more components the sound has to travel through it can become diminished and not as clean or clear in my opinion. And also people want lightweight amplifiers not heavy ones these days. Class D lightweight with minimal components and they're very powerful. Downside to class D amplifiers I don't like the switch mode power supplies I prefer a transformer they last a lot longer.
Seem like new generation don't have need for high quality sound! In the 80's most young people know brand for good high quality sound and we save money to buy it. Today they just listen to phone speaker or headphones. I think they missing a lot.
