MOSFETS normally have a very high gate impedance, yet usually requires a fair amount of Volts to turn on with high current loads. It also suffers from significant gate capacitance, so needs a low impedance driver to reach those higher audio frequencies. Just a thought: I always thought it was the dominance of the second harmonic that made a valve amp sound warm, they would also clip rounded. A BJT Amp will mostly clip as a square wave, so making the third harmonic dominant and sound harsh. Excellent videos/equipment you make, Paul.
It would be nice if other RU-vidr's took notice and learned by watching quality videos like Paul's that having people you fiddle with something for 5 minutes while talking about what you and your girlfriend ate last night (and its not a food channel) before even getting to the point of the video is not entertaining. Nor is going to a concert and trying to record the concert on your phone, think it will be "cool". And all you end up with is a blurry and bouncing video that sounds like crap. But everyone seems to want to do it. It's annoying to the fans trying to watch the show, and certainly not entertaining by any degree of measure for someone to watch on your RU-vid channels. Yet, there's thousands of videos like that on RU-vid. "If" you have an iPhone (Apple) and can stabilize the phone you may get some decent video. The cameras on those things are crazy good. But there isn't a single cell phone out there with a decent microphone, especially one to record live music so your good video is still going to sound like crap. It's a music a concert. The sound quality is the most important aspect of the recording. You'd think before going and doing that they would look up online some of the processes and equipment professionals use to record concerts. And learn it's best to not even try. Just enjoy the show! lol Sorry, but as much as I like RU-vid for the most part, there are way too many crappy produced channels. No Quality Control. Everyone wants to be a "star". lol Take care.
I had a Pioneer FEX-95 (Centrate). Nicest car deck I've ever had. Sold the car. Moved it indoors. Long story short, a buddy and I compared it to a Sony ES deck and a Harman Kardon 391. All three of those decks sounded about the same. Perfect. That was back in the days we recorded albums for playing in the car. There were some astonishing car decks, back in the day. Of course, there was a lot of astonishing stuff, back then. These days, only a handful of small manufacturers, like PS Audio, still care about sound quality.
Far too much is made in China. There are over 200 brands of aftermarket car stereo brands (I do car stereo installs, when people have money anyway. lol) and 95% are all made in China. A number in South Korea of some of the better brands (and if you can afford should look for South Korean made eqpt) with just a handful made in America (which is the best in my book) and a few in Europe, and Japan. Japan hardly makes car stereo equipment anymore like they did back in the day. And Japanese stuff is very good too. But that's the problem with what you mentioned about sound quality. Too much crap made in China with attitudes of not caring what is being produced, and poor quality control on top of it. Since you are a purveyor of fine equipment, I'll let you in on a little known secret. You want "the best" stereo drivers (woofers, mids, and tweeters) that are better than 99% of the offerings out there, and are affordable without the crazy prices: SB Audience. They are made in Indonesia by one of "the finest" speaker manufacturers in the world because they are 100% vertically integrated. In other words, they do not use any outside parts, making everything in house. Something very few speaker manufacturers do. SB Audience only makes professional level speakers. But, not finished speakers, only the drivers. Most of their offerings come in both 4 ohm (car) and 8 ohm (home). However, the only distibutor in America is Madisound. Still, the speakers are affordable compared to other high end speakers. Ex. woofers start a little over $100 each. Tweets $40-$60. Sure you will need to come up with boxes or cabinets. Or many will fit in standard speaker placements for cars with just a plastic adapter ring to secure the speaker. You can't go wrong with these speakers. Soon as things get back to "normal" on my end, I'm going to outfit my car with all SB Audience speakers. By the way, pretty much "anything" offered by Madisound, regardless of price, is a very good performing speaker, much better than what you will find most online stores. Meaning anything you purchase from them will make you happy. They are a little "audiophile" snooty, but that's because its ran by engineers, not marketing guys. I highly recommend anything they offer. As well PS Audio as well. I sure would like to. Most likely in a "used" form most likely. lol. But a higher end used system is better than a new crappy stereo system in my book. And generally how I come across my personal audio gear since I'm working to make ends meet these days like so many others. Hopefully that will change this November, and America can get back on track being the badass country it used to be. lol. Take care my friend. (PS. If you are wanting to "upgrade" your car stereo, don't buy car stereo eqpt. buy Marine audio eqpt. Marine audio is all 3rd party tested and certified unlike car audio. So even your non-name brands Marine audio is on par with name brand stuff. It has to be to pass certification. The best offerings by most mobile audio companies is their marine eqpt. I used to live in Houston, TX and do boat stereo installations, and that is how I learned marine eqpt really is much better than what is offered for cars. In both durability and sound quality. Even, or especially the Chinese stuff). Now go and crank it up. lol
MOSFETs are superb for switch mode power supplies. For audio great sound can be had with MOSFETs, tubes, and bipolars. Maybe a discussion of JFETs in phono preamps is in order. One thing I've noticed about large power amps with MOSFET outputs is that they tend not double their output into loads where the impedance is halved whereas serious designs with bipolar outputs do. Two examples that come to mind would be Krell & the old Aragon amps. With those you'll see ratings like 200W into 8 ohms, 400 into 4 ohms, and even 800W in to 2 ohms. What remains consistent is that every setup requires individual evaluation. The best sounding amp I've ever heard through one speaker might not be through another.
@@davidstevens7809 I'm an EE but I haven't looked into the reason why. Their gates do have significant capacitance but I haven't studied what that does to slew rates and other factors. A very low "on" resistance is what makes them so efficient.
Still to this day, one of the greatest sounding amps I’ve ever owned was the Precision Power A404 Art Series amp from the mid 1990s. I believe this had a MOSFET design.
No.its not mosfet.. its 2n6487 and 2n6490.. bjt output..thats why they are current limited..now is the time to tell..I HAND MADE PUNCH 45s for rockford in the 80s.. Im directly involved in amp evolution..and design.. ha ha..
@@koprcord5338 ? Explain..are you asking about makers distillery? Its hour from louisvile..but..i actually cut some shutters for the buildings back 40 years ago..yup..i worked there..temporarily.
I had a Pioneer DEH-6700MP (yes, the swimming dolphin display one) in my old '92 Crown Vic. Best sounding stereo I've ever had. Kept it when I sold the car. Clearest, deepest sound. Pioneer used to make really good stuff. I never knew if it was the Mosfet architecture or something else that made them sound so good
MOSFETs are voltage controlled current sources while BJTs are current controlled current sources. MOSFETs have high input impedance so they require little current to be turned on but fairly high voltage. They do not suffer from thermal runaway as found in BJTs and they exhibit distortion similar to tubes in that they predominantly have even order distortion products. BJTs have both odd and even harmonic distortion which is more objectionable to most listeners. The even order harmonic characteristics of MOSFETs are likely what give them "tube-like" warmth
I did notice that in the car it would get extremely hot and it wouldnt be quite as good sounding but in my house in the ac it stayed cool even when cranked up full volume
Lateral mosfets are the only sub-type, where the drain current vs gate to source voltage drops with the die temperature from about 120mA of DC bias per pair. For hex-fets, this relationship still exists, but only for drain currents measured in amps. Distinction in regards to thermal runaway susceptibility should be made between the two.
@@BruceCross Hate generalizations, as the devil is in the detail, but lets say hex-fets should ideally still be thermally compensated, whilst lateral fets need not be. Lateral mosfet output stages are rare as hens teeth and the ones designed correctly even more so. In my opinion and to my ear, lateral mosfet current stage amps done correctly sound superior to pretty much anything else, including tubes, but at a price.
Pioneer literally pioneered using Mosfet chips in their car stereos in the late 1990s. The first ones were branded "MOSFET45" which quickly became "MOSFET50" shortly thereafter. Any Pioneer radio that had a Mosfet chip also came with a parametric 3 band EQ (branded as "EasyEQ" or "EEQ" for short) which was also a breakthrough. Most aftermarket car radios at that time only had bass & treble controls. Very few had a midrange control and nobody had a parametric EQ built into the head unit until Pioneer did it. Car stereos really haven't advanced too much in the last 25 years since then. Pick any major brand and the amp chip they use now is nearly identical to the one they used 20 years ago.
My first real higher-end amp was a Adcom GFA- 5500. It had a smooth and sweet tube-like sound except with more authority in the lower registers. Being voltage-driven devices (like valves), MOSFETS tend to be more tube-sounding and the 5500 exemplified this. Bias (like other Adcom amplifiers) is toward class A, so it ran warm. They didn't heat the room like older Krell monoblocks. But it's also smoother sounding and less transistor sounding than the Krells.
There are many electronic engineers and physicists who would disagree with you about BJT's being current operated devices. Base current is a 'side effect' to the base voltage. There are many variations of FET from the low voltage J-Fets which operate a lot like vacuum tubes with similar circuitry, to high power devices MOSFETS using insulated gates in enhanced or depletion modes to handle high powers. Compared with a BJT output stage a MOSFET in class B will require a big bias voltage to control the cross over region. This reduces the power capability a little. Due to gate capacitance MOSFETS may be prone to oscillation. Horses for courses, as they say.
I once had a Eclipse (a brand of Fujitsu Ten) radio in a car and it sounded wonderful - so much so that at least one non-audiophile commented how good it was. It used MOSFETs. I wish they still made units for aftermarket installs. I think they are now exclusively OEM for auto manufacturers.
Trying to learn a little more about mosfets myself. My son picked up an old Hafler DH-200 amplifier which uses 4 mosfet devices per channel. I am familiar with BJT's and tube circuits, but if anyone knows any books of videos on how these devices work differently in the circuit I would like to learn more about them. Yes, high impedance voltage amplifiers they are. With that being the case, I would imagine they have more linear voltage gain than a BJT device. Thank all of you in the audio community, lets enjoy the music, cheers!
A few authors pop into my mind Bob Cordell and Douglas Self. You also have the Elektor Magazine crescendo millennium edition. But I have to warn you using older drawings even 10 year old for an amplifier project. Always check you can get all the components before doing anything. Like in the crescendo millennium edition. One of the transistors the 2sk537 is hard to get unless you are willing to pay exorbitant prices. Sorry RU-vid allow no links. But well the information is out on the web
Holy cow im sure you hear it all day but i have been researching transistors in my free time for the last 6 months and did not know that bjt's are for current and FETs are for voltage mind blowing 😮 wish i grew up with someone so clear spoken 😢 maybe i could have been an electrical engineer 😢
Many amplifiers nowadays have a little bit of sound that is not so warm. Especially class-D amplifiers? but also newer cheaper class-ab. This type of sound can be a bit sterile and boring and tiring for the ears.
@@36karpatoruski Do you have speakers and amplifiers that were made when cassette tapes were popular or radio. Talking about the 60's 70's and 80's. then this can sound too cold and bright with CD or MP3 music. What's Your opinion?
Yes, my hobby started in the late 60’s. Never heard a cassette sound harsh, but only made my own cassettes from LP’s, never bought any pre-recorded. Some harsh or thin sounding amps or receivers include units from Phase Linear, Crown, Carver, and Sherwood. 60’s - 80’s vintage gear. Of course, poorly recorded CD’s will sound harsh using just about anything for amplification. Also, harshness is a matter of degrees. What some people find objectionable, others may be ok with.
@@ford1546my dad had a home stereo from the late 70s (it had quadrophonic sound) that me and my brother used to play cds on and it sounded great we used it with a pair of speakers my dad built when he was younger
Another great video by Paul. I just want to point something out... Yes, Pauls initial is in the name of his company, but the amplifier is literally named after the engineer who designed it. I don't think I can name another audio company the size of PS Audio that does that (BHK 600). Nice!
Do mosfets improve the sound compared to bi-polar transistors when used at power amplifier outputs? I doubt it. The word "warm" in general evokes comfort and pleasure, but unless It is analysed, explained or measured, means nothing in relation to audio amplification.
I understand what your sayin but its hard to describe the sound without using all the buzz words like soft, pillowy, or warm. In audio terms i would say a colorization of the high end around 5k to 10k that makes sound less fatiguing to the ears, less harsh. It just sounds good though
@@JohnHarnickclass d are praised for their efficiency and size i have a one volume knob class d thats fits in the palm of your hand thatll get loud enough to drive the rest of my family crazy
@@Durkhead that gain in efficiency means (much) more current is going to the voice-coils. A/Bs intentionally drain that current. A/B amps were one of the great hoaxes of audio. A 'd' amp at 20 watts, was made in 1965.
Best sound I ever heard was 2 x Leak TL50 power amplifiers preceded by Leak .1% pre amps The speakers were Tannoy 2 Westminster monster speakers! Soft clipping even harmonics made music sound like it was live! Pipe organs are difficult instruments to record clean because of the frequencies and harmonics and the acoustics of churches or cathedrals! Listen to Bach’s to Tocatto in D minor and you will see/hear what I mean! Some organs have pipes in the thousands from piccalos to bass monsters 32 feet or even 64 feet in length! We are talking here bass frequencies 16HZ and lower which you don’t hear you just feel the modulating air around you! Trouble with valves is they are finite and emissions start to fade. replacing matched pair of KT88’s or 6L6’s is costly nowadays maybe £140 and more! I have heard some setups where preamps have valves in the early stages feeding into mosfet power amps and they sound pretty good and they cost very little! example is EF86 and others ! Some simple headphone valve amps sound very good even if they feed into mosfets although impedance matching can be a problem! Any body else find valve sound pleasing? Fraser
That's alot of "big" capacitors! I can't imagine that piece of equipment having a poor signal! lol Paul is right, sometimes you do come across a mass marketed piece of stereo equipment that exceeds all of its siblings and exceeding your expectations by offering really good sound quality. Or end up matching perfectly to a particular set of speakers allowing for the same result but wouldn't if other speakers were used. That's the funny thing about electronics. But when it happens, it's like winning the lottery.
@@terrywilliams7827 *Quadrax* That was the name of their new 4-way car speaker in 1981. When you mentioned "axle" it just didn't sound familiar. I finally found an old magazine ad online. I kept searching Quaudaxle and nothing but coaxial and triaxial would show up. I was beginning to think you had the only pair ever made, lol! Back in 1976 (when I was 17.) I bought a pair of new Triaxial 6x9 along with a Pioneer Super Tuner cassette deck to mount in my '68 Chevy Chevelle. Driving though an intersection on the way to my gas station job someone decided they didn't want to stop for the red light and plowed into the passenger side. It was totaled, so I removed the speakers the cassette deck and my almost new battery; set it up in mom and dad's basement and continued jam on some Led Zeppelin. Didn't sound half bad, lol!
Derek in Florida has obviously not heard some of the finer offerings from PS Audio, or in my case a used JBL system. My system is completely noise free, no hiss or hum, and neutral with its soundstage with high headroom. You hear the music as it was recorded. Most of the time it is a good thing. But on older recordings from the '80's and earlier you sometimes wish there was something you could do to make the music sound better. And I would guess nor has Derek heard a professional sound setup in a recording studio, which to me is on par with any "audiophile" system that costs tens of thousands of dollars more. God love PS Audio, and Paul and everyone that works there in their pursuit of the perfect sound system. But sadly, not all of us can afford the perfect system. However, that sure doesn't mean I wouldn't like to own some PS Audio equipment someday. As I listen on average to 4 hours of music a day, and I'm a musician (drummer) and music is the most important thing in my life after family. But even my JBL system I picked up used. Believing it's better to have a used higher end stereo system than a new crappy stereo system. lol. Life without music would be a mistake. Peace.
I had an amp that was sending a pulse (came out as a loud thumb) to a speaker when on standby and later when playing. The manufacture immediately identified it as a degrading MOSFET. I hadn't a clue what they were.
What is the bias in and amplifer and what is it for? I live in Trinidad in the Caribbean, a fan of your videos. I currently own a creast 9001 and on one channel the clip light come's on and off continuously. Someone told me that the bias need to be adjusted.
Are you sure ?? I mean I heard every word you said and it makes sence . But ; Mosfet! I am pretty sure that has something to do with Moses in the Bible. ( I hope this takes the price of the "best" nonsensical post of the day😬) Have a great day all Hifi lovers🙂
Ok . The pioneers have a part #pal 002-or as they update ..003..004 etc..the the pioneer number..in reality theyre Tda7384 parts made by ST semi..I think.every car radio brand uses a varistion of that part..yes its mosfet.. alpine uses tda7560 I think ..an ability of mosfets is they arent as picky about load impediance..bjt designs are plagued by a problem called thermal runaway..there are ways to calm the problem.( emitter bypass cap) but thats another topic..mosfets are more stable for the most part.I can tell you my friend invented the all N channel output stage design that everyone copies these days..the reason is..p channel mosfets are inherently weaker that the N channel ones .they dont bias exactly the same either..so my friends All N channel changed the world. I suggest amps with all n channel output design..
In an earlier video you said that class-A amps use full power at idle. The correct is half is it not? Because the Q-point is placed in the middle of the transfer curve. If it used full power at idle it would only be able to handle negative swing(amplitudes) and no or very little room for positive swing
Class B and AB are inherently push-pull. Class A can be single ended or simply a class AB where the "pull" side turns off only on the full "push" side and vice versa. But if you have that for 8 ohms and load it with 4 ohm, that will run out of current and become somewhat class AB; if you load your typical class AB with 1000 ohms, it will probably be able to do that in class A...
Topics that can be easily googled shouldn’t be answered on here. Also, too many repeat questions from people who actually don’t watch this channel at every upload.
Approximately 6 or 7 years ago, the CD player in my 2003 Nissan Sentra was unable to eject CDs. Something mechanical finally failed. I purchased a Pioneer replacement, based on the recommendation of the store. Argh! Horrible. It yelled the music at me. I struggled to make it through any song to completion, inevitably skipping from song to song, and within 3 or so minutes, I had to turn it off. I returned that Pioneer unit. I went to a different seller. He was kind enough to hook up a Sony, JVC, and Kenwood, in order for me to choose the one to my liking. All were better than the Pioneer. But the Sony and JVC were boomy. I got them to sound decent. But it was two steps down from my stock stereo. Then when I tried the Kenwood (it was the last one I tried), it was a breath of fresh air. It sounded every-so-slightly better than the car's stock unit. And it has USB inputs... so no more CD swapping. I also own a 2020 Honda Accord, and its stereo is decent, but no match for what Nissan put in my 2003 Sentra. Someone at Nissan had a great ear for sound quality back then, and got it right. For a stock stereo, in a nothing special car, it was very clean, musical, and I could listen and listen and listen. I would love to swap out my Accord's front-end unit. But cars these days have everything integrated into the console, making a swap expensive, and will void the car's warranty, and who knows what wiring or computer issues might surface. So customers are basically stuck with factory head units in today's cars. Anyway, that Pioneer unit was torture. You could not pay me enough to listen to it for 20 minutes.
Just to let you know, your 2003 Sentra probably had some small DSP functionality built-in which probably included a factory EQ curve to improve the sound through the factory speakers. Were these types of vehicles swapping the OEM head unit can actually make things sound worse because you've removed the eq. I don't think that would explain why some aftermarket radios sounded better than others, but it's something to keep in mind. As newer vehicles became more complex and radios were more heavily integrated, a whole new market opened up that allows people to upgrade late model cars.
Hi, I also bought a Pioneer car stereo, I too found it very harsh sounding no matter what you did with the settings couldnt really get it to sound nice, I returned it and also got a kenwood, really nice solid warmer sound, kenwood car stereos seem to have a unique sound quality
@@andrewwalsh5837 Both of you guys are acting as if the brand has something to do with a sound. Each of these brands makes many different head units over a wide price range. If you were listening to the cheapest Pioneer model it may not have sounded as good as a medium-priced Pioneer model. And an upper priced Pioneer might have sounded amazing. So there's really no rhyme or reason to believe that an entire brand sounds bad and some other entire brand sounds good. That's kind of silly.
@@JasonWW2000 "Both of you guys are acting as if the brand has something to do with a sound." Well, of course the brand has something to do with the sound. In fact, it has everything to do with the sound. "Each of these brands makes many different head units over a wide price range." The differences in price were due to features. According to the shop that sold and installed my Kenwood unit, all of them have the same sound quality (same built-in pre-amp, and amp). Pioneer did make a unit that was 5x the price, which I did not hear. But among the Pioneer that I did demo, and the Sony, and the JVC, and the Kenwood, they were all priced within $20 of each other. I did not go for any features that I would not have used (I can't remember what those features were, but they had nothing to do with the sound quality). The Pioneer sounding nothing like the others. The Sony and the JVC were both boomy (I did not spend time critiquing the rest of its sound quality, because I would never buy it, and I was using the shop's time). The Kenwood, with all of its DSP, equalization, or whatever else it has or whatever it is called, sounds fantastic, with everything set to neutral. The other brands just sounded bad. And since I rode around with the Pioneer for a few days, I tried every setting it had. It simply yelled the music. It was an irritating sound.
@@NoEgg4u The guy at the shop that told you they all sound the same and it's just different features didn't really know what he was talking about. Logically, does that even make sense? The different radios have to hit different price points. The more expensive units can use higher quality components and design to deliver higher sound quality. The cheaper units have to compromise on the design and use lower quality components which tends to create a lower quality sound. It's pretty much the same with any audio company talking about receivers, speakers, amplifiers, etc...
