When is a tube power amp not a tube power amp? - Aiyima T9 review

If you think that this is a tube power amp you'd be wrong. A power amp with tubes though? Maybe you're right!
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Irritating unboxing music by some geezer called David Mellor.
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CHAPTERS
0:00 Chat
0:42 Unboxing
2:24 More chat
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Disclaimer: Videos on this channel may include affiliate links and may feature software that has been received free of charge with an NFR (not for resale) licence, equipment that has been loaned or donated by a manufacturer or distributer, or equipment that has been bought for less than full retail price.

[@Smithy225]

I can't quite put my finger on why but I could listen to you all day. I'm not even sure the topic would matter. You're very articulate and interesting

[@richardmarkham8369]

Yep, great speaking voice!

[@richardgoldsmith8592]

It’s sort of like ASMR for geeks 😅

[@garymalone547]

Haha me too. However I am fascinated by the snake oil which is rife in this hobby. Plus I renounced analogue sources many moons ago in favour of streaming. Qobuz at the mo. Wasn't sure what to say when a girl asked me if 200 watts was good for a Bluetooth speaker yesterday. Started talxking about RMS and ended by saying bigger is better.

[@QuintEssential-sz2wn]

Interesting, because while I like some of his topics I have a hard time sticking through the videos because of the delivery. I find there's a sort of smart alecky, yanking-your-chain delivery that's a bit off-putting leaving me often wondering "what is his actual point, or opinion on anything?"

[@Smithy225]

@QuintEssential-sz2wn I guess we all see things differently. It's all good though 😌 👌 ☺️

[@billklement2492]

I've had one of these for a year now. My PC feeds it through optical. Sounds pretty good. I like the tubes. They glow! And don't negatively affect the sound. I also like the VU meter. If you need more than 25 watts, I'd look elsewhere. And check the power supply! You can't get 200 watts from a 100 watt supply! But I highly recommend! I generally prefer simple amps without tone controls or switching. As little in the signal path as possible. But this one sounds fine. Always remember... The music you listen to has been encoded through a microphone or other transducer, generally brought into the digital realm for mixing and processing and returned to the analogue realm in some manner. So having a $5000 amp isn't going to make that recording any better! If you want really accurate music, get an acoustic guitar. Then you can argue about the best guitar!😁

[@user-fu8vn7xo6c]

Yes, this is a compact hybrid integrated amplifier, with tubes for the preamp & a solid state amp. A good value for the price.

[@barlow2976]

I couldn't stop laughing when you went fuzzy as soon as you said the analogue word. I too grew up in the transistor world, though I had a huge radiogram in my bedroom, full of tubes. I was bought a tiny, tinny, transistor radio for my eigth birthday, and gained more pleasure from looking at its circuit board than listening to it. I had no idea what all those multi colour transistors actually did, but I knew it was the future. I had no idea we would be seeing tubes again- in the 21st century ! I thought we would be wearing Baco-foil suits and have flying cars!

[@jefierro]

if I had a hat Sr. I would use it to salute you, I love you fantastic , no nonsense, fun and straight forward review. here here!

[@earthoid]

I burned out on tubes back in the late 60's (yes I'm very old) when my stereo tube amp had two versions of turning on: 1-start up normally with audio, and 2-plates in the tubes glowing red hot with no audio. I switched to relatively harsh sounding transistor amps of that time because at least they started up reliably and didn't try to melt down like the tubes sometimes did.

[@peterdavies5358]

We don't have enough information to specify the quibble factor. I bought a headphone amp in kit form with valves in it for added warmth. Once I got to look at the circuit I could see that the valves weren't in the audio path so the only warmth that the valves could add were in their ability to radiate heat and warm up the room a little bit. If you could post the schematic or circuit diagram then we can perhaps judge the quibble. They might be a preamp and therefor add a bit of audio warmth or they might do what mine did, I can't remember what that was or even if they did anything at all but beyond the quibbleisation, you didn't give a price that I noticed but these things are great fun if they don't cost a lot and there's a lot of stuff and nonsense said in judgement of class D. You can have a big, proper hifi and a second one with a few different kinds of weird amps and preamps and muck about with them to your hearts content. Like Lady Bracknell said, a man needs a hobby. I say buy it if it doesn't cost a fortune and calibrate your own quibbles.

[@ghostjacker]

That was a pretty good Jeremy Clarkson "Power" imitation 😂

[@AudioMasterclass]

Sadly I think that's who I got it from.

[@DPSingh-px4xu]

The lesson today is precisely why I attend this class and most importantly I fully understand everything Sir said today so pleasantly...thank you very much

[@johnbrentford5513]

Honestly USB 2.0 is all you need for music the transfer rate is already higher than you need.

[@thefloop2813]

Love the videos! Ill start there It's pretty obvious to me how these measurements are taken, and many others too, and i dont see anyone trying to hide it. And if you know how a capacitor works and have seen the inside of a modern class d amp, no one should have to explain this to you at all. BYou can most definitely get more then a total of 100W of output power from a modern class D amplifier running on a 96w brick. You wont get sustained power that large, but you can absolute go beyond that 96w in peak burst for kick drums and whatnot. If you open these up youll find a couple massive 2200+ UF very high quality electrolytic capacitors to store and supplement the power of whatever supply is attached. And these chip amps are incredibly, incredibly efficient now a days. You can absolutely set that amp with that brick at a constant output of around 85w with peaks upwards of 150 and you likely wont ever even perceive any clipping, or just barely. And if you have a good psu or quality brick, it wont even get much more then luke warm to the touch. Even when our systems are loud, the majority of what we hear is under 50 watts of power per channel to reproduce, rest is peak unless your trying to drive a line array or something with drivers out the ass. Those bigass energy storage capacitors in the class D amps ARE indeed being used for something... Energy storage. If you short the legs on those caps, or pull em out and bridge the gap, your amp will still work, with a max peak wattage of whatever brick is attached. (DO NOT DO THIS EVER, you could very well start a fire with your psu) you can even increase the capacitoy of these large caps as long as you keep the same or higher voltage rating, and you can actually increase the peak output power just a hair and push the clipping back just a bit. Although anything beyond 2800uf doesn't really change much. For a reason i dont care to ponder or bother learning. There's a good chance if brought up to a clipping at, probably around 90-92w total draw from the brick, youll be able to pull 100w per channel, peak output (albeit with plenty of distortion) without taking ANY of the equipment beyond its max rating, assuming they used high enough value, quality electrolytic for energy storage in the amplifier. Most people would probably find this uncomfortably loud already unless they have large low sensitivity speakers, or arrays of many drivers For anyone curious this is also why Fosi isn't being eaten alive by the market for "Lying" so blatantly. They aren't lying, they are just very aware what kind of power these amps can pull off what kind of source and dont care to take measurements at huge distortion levels just under the limits of the hardware. Cats over on the forums have shown this time and time again as well how they get the output ratings they do. Its far from the best way to take these measurements, and it is borderline gimmick, but they aren't lying about output anyway. Nowhere on any of these specs does it say "RMS" and we have ALL known for years that if a manufacturer doesn't put "RMS" next to the output figures, it's peak rating by default... And there is NO WAY you dont know how capacitors work. Class D amps tend to have even larger capacitors then the attached power supplies for a damn good reason lol. It makes the direct wattage rating of a power supply less important for total perceived volume and keeps the attached psu from having to work as hard or respond to changes in dynamics so quickly. Plain and simple. Itd be cool if they posted RMS figures, but thats getting harder to track down these days even from larger more reputable companies. And this should all be quite obvious and assumable imho by anyone in the audio world besides the beginners. To beginners, If you google the question the first hit will likely be a forum post on DIYaudio explaining exactly how they land at these figures, these amps were somewhat designed over time with the help/input of the guys over there to begin with.

[@chrlz904]

Long winded, but .. yep. 😊

[@shipsahoy1793]

@@chrlz904 yes long-winded and way over analyzed lol bc the bottom line is .. regardless, it's still a cheap "chit" amp, mainly for appealling to people who like small packages and their own personal version of eye candy.😉

[@richh650]

Another great review.

[@bgravato]

Class D amp with tube preamp, that's what it is... I haven't tried the T9, but I had the T9 Pro for 2-3 weeks. It was disappointing and I eventually returned it to amazon for a full refund... I first tried it just as a DAC/preamp (USB to PC and aux out to a pair of powered monitors, in a near field setup on my desk) and compared it to a Motu M2 interface. First thing I noticed was that it added a fair amount of extra "reverb" (I'm guessing that was the effect of the tubes?), which actually sounded kind of pleasant in "dry" recordings, but way too much "wetness" on not-so-dry recordings. Then I tried it with a pair of passive speakers and compared to a vintage Philips FA950 amp. Differences were fairly noticeable... With the T9 Pro it sounded kind of veiled... it wasn't lack of power, but it sounded like the sound was coming from the end of the room, behind a thick curtain, poor soundstage/imaging. With the vintage Philips, soundstage was much more "upfront", everything was more lively and acoustic instruments sounded more... "natural". Bluetooth had issues and so did the remote (sometimes it worked sometimes it didn't...). I ended up returning the T9 Pro for a full refund from Amazon. A few months later I got a Fosi V3 and compared to the same vintage Philips, my middle age ears couldn't really tell much of a difference... I still have the Fosi V3, which replaced the humongous Philips, that was way too big for the space I had available for it... with the added bonus of the class D efficiency that reflects in the electricity bill too. Maybe I got a defective T9 Pro, or maybe cheap tube preamp sound isn't for me... I probably will never know :-)

[@AllHandlesHaveBeenTaken]

The GE tube sound much better

[@msingh1932]

I like the Master for letting the ladies have the last word...A true gentleman.

[@djtbs1]

Another greatly enjoyable video.

[@DaveMorris]

As an audio guy (phile might be pushing it), I'll be settling in to watch all of your videos. I find it interesting that I have a little tinnitus, and I'm almost 60, but I can still hear mostly the whole range. Maybe my brain has a built-in algorithm that fills in the missing material. Or maybe I'm clinging to some hopeless fantasy that I'm still the man i used to be. Either way, I get by, and I'm glad i found your channel.

[@Karto86]

Can you really hear 15k+ hz?

[@DaveMorris]

@Karto86 I can, yes. 16k is about my limit, but it has to be very quiet in the room. And, it does depend on the time of day. After editing and mixing all day, I'm much less likely to be able to hear it than fresh in the morning. I'd best enjoy it while I can, I'm sure within a few years that upper high end will be gone.

[@curtiscroulet8715]

I emphatically agree about auto trigger or on/off circuits in amplifiers. If I turn it on, I want it to stay on until I flip a switch to turn it off. I listen to mostly classical music, with occasional forays into pop and jazz. Some classical pieces start very quietly. Will the amp turn on in time?

[@thomaslutro5560]

My guess before watching: A tube amp stops being a tube amp when it stops distorting, and starts having a flat, impedance independent, frequency response. Or when it starts being a HiFi amp, and stops being a guitar amp.

[@MichaelYates]

Nice review. I had a couple of these types now and they are ok for what they are, but not real HiFi.

[@edholmwood2263]

USB "A" and USB "B" connections are far more robust than type "C".

[@AlanJEdmonds]

I’m not sure what the encoder resolution is like, but if it’s high enough that breathing on the volume control would generate pulses, perhaps the detents help prevent unwanted volume changes. (Or maybe the maker thinks it gives the control a more upmarket feel…) I’m sure some will assume the valves drive the speaker, and even though it should be obvious this isn’t the case for the reasons you stated, I still think it’s misleading. Oh, and the auto power-off would annoy me too!

[@amcluesent]

My Audio Analogue Cherubini VT Tuner has a tube output stage, it takes about 30 seconds to heat up from turning on

[@josecintron85]

if the auto sleep is an issue the t9 pro fixed that problem.

[@frogandspanner]

Old valves were often not tubular - but tapered. So why did 'Merkins call them tubes? I have built a valve amplifier in a bell jar. It has a high-vacuum system, now with an air-cooled diff pump since I removed my turbo-molecular pump after doing some calculations that showed that if the bearing seized it would take the wall out of the front of my house. My system is a damned sight more impressive than the amp shown here, but at a metre tall and 300 mm in diameter is not likely to promote marital harmony. I have a recording somewhere of it being used to play the Beatles in German, with the sound of the vacuum backing pump providing backing harmonies.

[@andymouse]

Turbos don't cut peoples knees off any more :)

[@frogandspanner]

@@andymouse Calculate the kinetic energy of a TMP at 90000 rpm.

[@EElgar1857]

IMO, anything like the device in question should be called a hybrid amp; the tubes on top are just for advertising purposes.

[@keithkrieger7075]

The power input says it will take 16 to 30 volts. A 30 volt power supply would definitely bump the output.

[@xxxYYZxxx]

The seemingly outdated USB input is ideal for connecting to a stationary PC, such as in a desktop system. The USB input frees up the Bluetooth input for a smartphone, iPod, or a laptop computer. I have an Aiyima preamp with the tubes, and its BT input sounds unmistakably better than running a USB from the headphone jack on my laptop.

[@karlos543]

Considering this amp has been out for a long time, I don't understand why you didn't test the 'pro', which took over this I suppose. Loving your presentation though 👍

[@atoptip6193]

Half a century ago, the claim was, when pushed to their limit, transistors start distorting in a harsh, unpleasant hockey stick manner, whereas with tubes it is gradual (like a jai-a-lai stick?). At some point, somebody must have said, why not buy a bigger amp and never have distortion? So now it all about warmth…embracing the distortion.

[@AllHandlesHaveBeenTaken]

The tube is in the "preamp" stage which is the only place you might want a tube. And tubes have distortion on even harmonics vs transistors on odd harmonics. The human ear is more sensitive to odd harmonics and that is why tubes can sound better to humans even though they measure worse on the bench

[@scottlowell493]

I’m not sure how many products are like douk/ nobsound, but a lot of that cheap tube gear is at best, a tube buffer. Mosfets are the output.

[@MichaelBeeny]

I wonder if this uses the usual RF valve. I have never seen any of these cheap amplifiers actually use a proper audio valve like an EF86? I doubt it. The gain these RF valves gives is very low. Most of the gain is normally given by a NE5532. Or similar IC. The valve is not really needed at all in these circuits. Just eye candy for those that think it will sound better. In reality all it does is add colour (distortion) and generally degrade the sound. If you think it makes better sound, go for it, why not!

[@damirhlobik6488]

Maybe NOS Telefunken ECC 803 S will improove sound 😂

[@depafeo]

Kind of off putting that this doesn't have a headphone output. I would think a main use case for a desktop amp would be for headphones?

[@pablohrrg8677]

I grew up in an era when tubes were like dinosaurs that should go extinct because the list of problems with them were longer than the benefits of a supposed "nice distortion" (now called warmth).

[@ryanlawrence3690]

A VoiceOver during unboxing is the way to go sire

[@AudioMasterclass]

No thank you.

[@Projacked1]

Ahhh...that good old muscular control knob. Where did the times go.....? damn.

[@ohwhyevenbother]

Class A baby! It's the only way to fly............))

[@chaoticsystem2211]

maybe the power is interlaced :D does it draw more when you feed it 30V?

[@AudioMasterclass]

I don't have a 30 volt power supply so I don't know. As for the interlacing, I might ask Phil to comment.

[@paulstubbs7678]

Yes to all your comments, these amps seem stupid to me, kind of a valve filtered pre-amp feeding a class D I did think of using one as a pre-amp, forgetting the class D bits, but then there are those valves poking their heads out just asking to be broken.

[@bluelines1792]

There isn’t a place for the sticker to go on it but it can stick it to a pole near a hifi shop.

[@richardmarkham8369]

So when it goes to sleep, does it turn off the valve heaters? I mean valves just love being switched on and off all the time!

[@thefloop2813]

its recommended to keep transistor A/B amps on all the time. I would not recommend this for class D amps or tube amps though. Not one bit. That is unless you want your tubes to only last 3 months. The heaters will outlast the grid or the plates, and generally only tends to go if the tube loses vacuum. And the plates, which often run upwards of 300-400v (Probably only 60-80 in this amp though) will definitely thank you in the long term for not having power running through them 24/7. Just my 2 cents 👍 Although the few mosfet class A power amps with tube front ends that exist, usually have a way for you to power down the tubes without turning off the rest of the amp for this very reason. Were not playing recordings through guitar amps here with cascading gain stages and tubes that have to be hot for a bit to saturate with gain properly lol. Nor is the heater filament anywhere even CLOSE to as fragile as the filament in a modern, engineered for profit, incandescent light bulb either, which definitely doesn't like being flipped on and off repeatedly

[@keithkrieger7075]

a linear power supply would improve things as well.

[@malectric]

I think tube/valve (yeah, living in New Zealand it was always valves up until the internet struck) preamps are a waste of money. A class A low level stage is still a class A low level stage (but with "tubes" running off AC heater voltages, with a bit of mains hum thrown in so you know it's genuine). Not to mention some microphonics if the DC supply voltage is high and possibly rattly guts as well. But of course the heater supply for this little darling will be DC so that disposes of an artifact that should have been included. To the point: if the output stage ain't tube, it ain't a tube amp. It's all about the way the output stage interacts with the speaker because as everyone knows, if it doesn't have overall negative feedback driving the output impedance into the dirt, it is instantly differentiated sonically from a transistor amp (if its not a transconductance type). The enormous benefit of the little package being demonstrated is that you can see the tubes lighting up so you know something is happening (as well as being a pretty little display for stoners listening in the dark). And if the anode voltages are high enough you might even see a dim blue glow in the glass envelope. And one last point: some of the power from the power supply goes into lighting up the heaters which only decreases available output power. My comment summary: Truly a "You Tube". Not!

[@theheathster2]

I’m not convinced that a unity gain valve stage is anything other than marketing nonsense. I got one of those valve phono preamps, Fosi I believe. My all transistor/op amp preamp was a far more pleasant listen.

[@dangerzone007]

Drinking warm beer that's your first mistake.

[@arielcandoleta5347]

Valve is a more accurate description I think.

[@maxbg]

Get the T9 pro with the higher voltage power supply. Problems solved.

[@Synthematix]

Theyre probably 12AX7 valves, meaning this is only a valve preamp

[@ac81017]

Cool little amp if you want to become an amateur Audiophile. As an Audiophile i wouldn't touch it with a barge pole, i'm sure audio Phil agree.

[@AudioMasterclass]

Don't worry, Phil has one. He's using the ultrasonic Class D switching noise to try to communicate with the bats in his belfry.

[@hdrmadness2731]

@@AudioMasterclass 😂 see now that joke should have made it into the video, I’m dying over here

[@1974UTuber]

It's better described as a Class D amplifier with a tube preamp stage. So glad we didn't hear from Audio Phil. That guy creeps me out.

[@AudioMasterclass]

Don't worry! Phil's taking a break to upgrade his supercooled cable lifters. He'll be back soon.

[@schemkesa]

😂😂😂​@@AudioMasterclass

[@1974UTuber]

​@@AudioMasterclassNnnnooooooooooooooo

[@mycosys]

When its a Hybrid starved plate distortion monstrosity

[@philipkershaw7918]

To deliberately introduce colour and warmth - ie., distortion - into the signal path is, well, just plain bonkers. Amplifiers should be heard but not seen!

[@andymouse]

No LEDs and a genuine 5532, just fine....cheers.

[@virtuosomaximoso1]

"Valves are knobs and tubes arent knobs, logic states they're tubes. " -reddit

[@turbomustang84]

I'll continue calling them tubes even though valve might be more accurate mostly because the crap I get from Brits over us in the United States calling gasoline Gas because it's short for Gasoline which is perfectly correct but they refer to it erroneously as petrol which although it is made from petroleum it is refined into Gasoline so Petrol makes no sense and that's my protest LoL

[@AudioMasterclass]

'Motor spirit'. The term is 'motor spirit'. That's my protest.

[@ryanlawrence3690]

maybe it turns off due to thermal issues

[@AudioMasterclass]

It sleeps after about ten seconds of silence. With audio playing it will go on all day.

[@ryanlawrence3690]

noice, cool product@@AudioMasterclass

[@EricIolo]

All fur coat, and no knickers what I can see!

[@maidsandmuses]

Not a tube power amp; I would call that misleading. A transistor power amp with a tube distortion filter. Combined on/off/volume/mode controls are an ergonomic & functional mistake, big time. Call me a dinosaur but I prefer a dedicated button/control for every function, even if that means the front of the appliance looks like the cockpit of a 1950's Lockheed Super Constellation. Instant visual feedback on every control please.

[@MarkThomas-hm3ju]

VAAAALVES! ... Hopefully that brings THD to an absolute 0.00000000 % which current technology can only measure to 9N.

[@MarkThomas-hm3ju]

My poor attempt at humor. Not even sure what I meant by this.

[@mycosys]

They arent 'real' tubes if they arent hot and high voltage. This is a starved plate monstrosity

[@bert_52]

The tubes are 6K4 and those are Pre-Amp tubes. So this construction should be called hybrid. This thing is rubbish and I would never ever buy it. Btw, the amazon link says it is unavailable. Oh, I have turntables and my Pre-Amps are Chip-Amps, only the Power-Amps are Tube-Amps. I am not an Audiophile, but a HiFi enthusiast.

[@Charlie-UK]

Either people want a Valve Amp or they don't. Transistor amps with a couple of valves on top for bling purposes are not real valve amps simple as that. The Internet seems to be flooded with these dubious devices at the moment. There are many real Valve amps available, from reputable sources some even assembled in the UK, consider those instead. You won't be disappointed...

[@atoptip6193]

I thought your female helpers were the rational counterpaoints to Audio Phil’s goobledygook. What happened? Did they have a ménage à Phil? Decamp to his camp?

[@AudioMasterclass]

They're quoting comments found on the web and KZbin.