Kinki Vision THR-1: Will It Blow Up?

After repairing the Kinki Headphone Amp, Mark puts it through a Kinki Endurance Test, to see if he can blow it up again. Is it really over-engineered?
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[@Matt_Aquila]

"If you don't connect anything silly to it, it won't blow up!" - best electrical advice ever!

[@luminousfractal420]

and ive been told that before. my grandpa when he was teaching me to wire a mains plug as a nipper 😂 my parents werent so happy. and i proved them right when i plugged my scalextric to the mains in an attempt at a 30ft car jump out of the window. i got my bed on fire instead 😂

[@matthewseymour8972]

@@luminousfractal420That's known as the Clarkson approach "More POWERRRRR"

[@mr_b_hhc]

On par with "Don't touch it when you're wet"

[@AntiDot70]

Mark, you really need to start selling stickers and t-shirts with "If you don't connect anything silly to it, it won't blow up!"

[@nudebaboon4874]

I'd buy one!👍

[@AstrosElectronicsLab]

I want a t-shirt with his facial reaction after being shocked with that SMPS, with the caption: "Cor! Fkn hell!" haha that'd be funny.

[@RickMahoney2013]

I totally agree !

[@andrewwturner]

It's always a treat when you release a new video and what a gem this was. Not many people could explain thermal dissipation without sending their audience to sleep but you pulled it off perfectly. I bet you spent a considerable amount of time working on this short video... Thank you.

[@bask2140]

You often sound like an old radio announcer from the 1930s using a carbon microphone 😄

[@glennbarker222]

Good job you decided to do the follow up test and identified the duff input socket. Nice bit of testing, interesting.

[@abigailhowes5944]

I wish you lived near me, as I would bring some of my electronics that need repair to you. Mark you are a true technician., not just a parts replacer. I watch you repair things, make new parts from scratch, and analyze a problem. I have only seen once where you couldn't fix something, but everything else you could. You are a joy to watch! Thank you and keep up the good work!

[@BoredSilly666]

I have no idea what you are doing half the time or do I understand Electronics but I find these strangely fascinating to watch. : )

[@danhorton6182]

Would have been cool if they had made it so that when you put the top of the case on that it would made connection to the heatsink and drawn heat from it. Essentially make the whole case a heatsink.

[@allantoft9961]

And mark would have so much fun getting the case of then I tell ye!

[@Edisson.]

I have a 100W test amplifier for SW cooled in this way - a 50x20x17mm aluminum monoblock connects to the entire case - total external height is 30mm.

[@hashtag-shaneiacs]

Naim amps are made this way but they're bolted to the case floor with a thick substrate. I imagine the top would be too hot to touch if they're bolted to the lid instead.

[@Edisson.]

@@hashtag-shaneiacs I don't know about Naim amps, I built it myself

[@thedevilinthecircuit1414]

There are so many little things that occur in your diagnostics and demonstrations that are unintended teaching moments--but when I pay attention I pick up stuff that's not in any book. Thank you sir!

[@BenState]

Like what?

[@TheStuffMade]

It's a very strange design, usually you'd want the output impedance to be as low as possible so variations in the headphone impedance will not affect the frequency response.

[@ulrichfrank4270]

Repair video made me think this device was at the same time over-engineered (for show) and half-baked.

[@JohnCompton1]

$1,300? She's way too Kinki for me...Thanks so much for sharing!

[@Clusterworldde]

Did you see the USB cable with 20cm for $309 🤣

[@Petertronic]

Audiophools and their money 😂@@Clusterworldde

[@PaulHigginbothamSr]

John: when they put an insulater on their mosfets I don't want it either

[@sickofthestupid1067]

China has learned capitalism well ..........

[@markianclark9645]

She's too hot for me..even at my peak 30 years ago

[@DominicClifton]

Thanks for answering my question regarding the use of Kapton tape, very interesting. So essentially it's good for protection, but is definately worse than a thermal pad which is what I thought, but not quite as terrible as I thought.

[@peterlarkin762]

Kapton is better than some thick silicon pads. Thin Mica is better than silpads but you need thermal paste then, which makes them equal. Aluminum oxide is best.

[@richbrock9876]

Know yer onions 🏆

[@Dave.Wilson]

He knows his currents as well!!😉

[@enoz.j3506]

Unless someone overloaded the output,thermal stress probably killed it, the cooler you keep electronics ,the longer it lives. Nice one Mark.

[@codebeat4192]

Exceptional amount of detail, very talented at many fields.

[@rvmeushaw]

Fantastic repair as usual and an engineering lesson to boot! Great job.

[@TechGorilla1987]

This is the deep dive that I never asked for, never thought of and didn't know that I couldn't live without. What a fantastic series of tests to gather empirical data. Well done, lad.

[@mortjoer]

I'm a carpenter by trade and people seems to love to look over my shoulder when I work on stuff. This is where I get my own curiosity satisfied about other trades thanks to people like you Mark, Thank you 😊

[@alphaLONE]

Excellent work of verifying the claims. Love your stuff!

[@nabman_]

2.2W into 30ohms is 270mA. Why such hefty transistors? Why such complexity for driving headphones? The least sensitive ones would still reach painful SPL with mW. I don't get it.

[@chrisbartram3034]

No, nor me. Loads of power loss heating up the amp to drive a low-level load...

[@nabman_]

@@chrisbartram3034 with 70V rails....the art of snake oil....

[@eddieMurphy11111]

I often wondered what that plastic was called now I know thank you and thanks for the video

[@nevillegoddard4966]

@@eddieMurphy11111 Yeah capton. Cool name!

[@jinxterx]

@@nevillegoddard4966 Kapton.

[@davidtomsett]

Kapton is also used to make membranes for electrostatic and planar speakers.

[@Michael-h7y5k]

Mark, I know you hate them but I request more tape deck repairs. Pure joy for me. You are my favourite channel on KZbin.

[@gordonm2821]

Thanks for the in depth reply to the comments. I know there were many armchair expert comments on the original video but great to see the science behind the design. Still over the top for a headphone amp IMHO!

[@nordin_gh]

Adding fan on top would be nice but need more work with CNC machine to make the hole. Love your video always.

[@glynnetolar4423]

Oh no. You may end up with electrical noise from the fan.

[@quantumleap359]

Oh goodness NO! That would introduce distortion and offend those "golden ears".🙃

[@chrisbartram3034]

Why not just use the case as a passive heatsink, though?

[@tony359]

Thank you for adding science to the previous video!

[@ЮраЧернышев-ь9р]

A square wave signal of 500-600 Hz is also necessary for signal passage and transient processes in the amplifier. Always.

[@user-sh4zq4ge1o]

Love this style of video, more of these deeper dives into particular part of a design would be great.

[@Cee.Jay.71]

I've been away for a while but it's nice to see your channel is blooming. Thoroughly well deserved Mark.

[@s.wilson5675]

Well Mark, I'm glad you solved that 'heated' debate about whether the Kapton tape was good enough or not!

[@stephenyoud6125]

Nicely done Mark, as per usual !!

[@Dinobaburas.]

I got lost after you opened the aluminium lid 😂

[@stianhus]

that was just brilliant, you never cease to impress (and educade) Mark!

[@OldePhart]

Liked this one. First time I've seen the thermal gradients explained at all.

[@PileOfEmptyTapes]

Good lord, that thing can dish out as much voltage as a 150wpc speaker amp! Clearly a very particular design for those who really love their vintage AKGs (aside from the 120 ohm K1000 "ear speakers", the 600 ohm K340s come to mind). I imagine most folks are going to find the likes of a Topping L50 a more sensible proposition.

[@pantelisEVs]

Thanks for making this video! Really interesting getting into expensive audio equipment (for personal audio project design ideas :-)

[@bobgrob4]

Alright, Mark! Keep cranking out the vids! Mark I feel in my gut that your channel could be the most popular electronics repair channel on KZbin, given enough time and make a lot more videos. Before you know it, you could be repairing stuff and doing projects just for fun. Keep going, sir!

[@dvsbangkaeedivisi9369]

Yang selalu saya Tunggu....

[@TheFlyingBusman]

For a headphone amp, I’m surprised at the chunky MOSFETS but even more so at such a poor heat sink. The Chinese, bless them, churn out some interesting kit but let it fail due to attention to detail. I’d be much happier with some slots milled into the heat sink to give a bit more surface area or a few vents and small brushless cooling fan. Who would have thought a headphone amp would get so toasty but there you go.

[@chrisbartram3034]

I'm also a bit mystified by why so much power is dissipated in the amp to drive only a few watts into headphones.

[@crushboss]

If you are going to use a thermal imaging camera for heat transfer differentials (especially between different materials) you need to study and understand emissivity! Especially when trying to gain a accurate temperature on reflective surfaces. 2 Small pieces of black electrical tape on each surface will help, and set your emissivity to 1.

[@MlokKarel]

Mark... I would abandon my 15 years long career as a dentist in a blink of an eye, for a chance to become your apprentice. 👍🍻

[@semsem2841]

I watched your video in Thailand.

[@foxbeef1983]

My new favourite KZbin channel!

[@hugh007]

Excellent video. If I hadn't seen this, I would never know how over engineered a headphone amp could be. Cheers.

[@vinatechcoy]

Mark!. Thermal transferal from the internal heatsink to the case (top cover)

[@andyb7813]

Another Really interesting video Mark. Thank you

[@AstrosElectronicsLab]

I'd love to see you purposefully blow up a transistor due to exceeding the SOA.

[@xxxxDuke]

These videos are such a labour of love - thanks Mark.

[@schummiehugo]

good job happyman !

[@barrybradfordlocksport]

Love the channel need more uploads please mark

[@that_thing_I_do]

Can't wait to watch it at home!

[@NotMarkKnopfler]

It's all a bit much for a blimmin' head phone amp really, isn't it?!

[@scossa_vr]

Great Mark, very interesting, thanks for sharing! P.S.: your youtube channel is the only one whose intro I also always watch, too funny!

[@fretlessfender]

Wow! Nice new concept Mark! Love this! Something different for a change. If you ever find a stupid design, please show it! It's always nice to see pro-brands doing silly things!😂

[@juarezcastelo]

Ok ok! You were right about the kapton tape! You happy now!!? Great vid btw.

[@sjqideez6626]

Fantastic stuff Mark, much appreciated

[@Tintukees]

Hi, I have been watching all your videos. A lot of new things to learn from you. I wonder if you you could make a video on your tools and shop. The soldering iron you use seems to be your favourite, being small yet handy and long lasting.

[@GaitaPonto]

OK, you proved it wont blow up. But I still think this design could be improved. With all this aluminum available, why not use it in our favor and keep components cool and comfortable?

[@acswales]

Head in a shed again. Cheers Mark. Keep 'em coming. Thanks

[@jamescarver6275]

Thanks

[@wdavem]

Most interesting! I'm learning, I'm learning!

[@Dave64track]

Great content that test would certainly show up any problems if it had any. Trouble shooting is great when you find the fault and it works it's when you don't find all the faulty components and you get the dreaded magic smoke coming out.

[@greevooo]

Fascinating

[@cymaz100]

Brilliant 🎉🎉

[@billsmith5166]

Very interesting. Well done.

[@Bigbluevwvan]

nice in depth testing

[@johnmarchington3146]

I suspect the intermittent RCA socket might be due to its outer diameter (the earth) being ever so slightly smaller than usual. With my own audio system I've been surprised how much the diameter even high quality gold-plated plugs and sockets can vary and I've had intermittent connections on occasions.

[@edmaster3147]

Thanks for the follow up. Nice work as always.

[@kenneths9522]

Thanks, nice job Mark! I always enjoy your videos.

[@absurdengineering]

I have a 1kW brushless servo drive power stage on a tiny heatsink for messing about on the bench. Under full rated load, switching at 40kHz, it gets just about as hot as this headphone amp got. That’s running from rectified 400V 3 phase mains. That very power stage can be easily cranked up to 100kHz switching at lower voltages, and 70VDC would be considered nothing much for it. Then it could drive headphones as a D-class power stage. It will get maybe tepid with no heatsink at all then. I’m thinking Kinki could put a much better amp in the same case for same money, just reusing industrial VFD/servo power stages from scrap lol.

[@mixolydian2010]

Cheers Mark,nice experiment.

[@gijoemolinaro]

Love your vids Mark absolutely brilliant

[@oiygfdxssfgg]

I really enjoy your videos Mark.

[@awaazhoosein6565]

Hi sir I'm waiting for u to post more videos i love all the videos

[@christophermarshall5765]

I reckon you could build a decent amp using the Motorola high power output transistors. Those are MJL21193 and MJL21194, or you could use the TO3 package type MJ15003 and MJ15004. The latter require 160V and have output of 250 watts.

[@rjk5559]

Complementary output? Wouldn't a single-ended Class A design be preferable if fidelity was really the goal of a headphone amp?

[@peterlarkin762]

Then it would need a proper heatsink and bigger power supply, and a bigger price tag! Nothing wrong with complimentary, most class-A amps are exactly that. Single ended technically performs worse, and requires and output capacitor or transformer. They do sound lovely though.

[@rjk5559]

@@peterlarkin762 Class A is less efficient than A/B but this thing only need to drive headphones, not speakers.

[@LawpickingLocksmith]

Really Kinki!

[@Edisson.]

Hi Mark, phenomenal work, problem analysis worthy of a university professor 👍 PS.: How is AIWA doing 🤔 Nice day 🙂 Tom

[@billmilosz]

That bespoke headphone load box - very nice execution! How did you fabricate that front panel? Very nice. By the way, something like an AMB Labs Beta 22 headphone amp is much more rugged, has lower output source impedance (better damping factor, important with certain headphones) and an be made DIY.

[@Trucam2020]

Excellent education video 🎉

[@djdoo]

Very nice answer video ! But now I have a new question: What was that silly thing the owner connected and created some much damage to that expensive, and proved to be, well made headphone amp? In other words define the term 'silly' for this device.... Maybe 4 Ohm speakers?

[@davignonmemarc3000]

Again, a lot of fun !!

[@TechGorilla1987]

I was pleased to see on your web site that you're fully booked and can no longer handle new business. It's no wonder with your attention to detail, fastidious nature and overwhelming knowledge.

[@michaelcarey]

The "Mend It Mark Stereo Headphone Test Load" looks most interesting. Have you published this design anywhere Mark?

[@ZombieHorror666]

"For the specialist market.." haha.

[@samb2936]

This heatsink is a sweet one...loool

[@zuvinrat4155]

great as usual

[@ibrahimkocaalioglu]

I thpught you would change capton tape with thermal silicon tape and solid aluminium with fin one.

[@paulchisholm9392]

Thanks for the video. I have beem playing with Exicon MOSFETs in a Power Amplifier design and they do like to oscillate at many MHz. Maybe the MOSFETs died due to cross conduction of the N and P channels because of this?

[@peterlarkin762]

I've seen some references to this... sometimes people don't use gate resistors, or emitter resistors. In real life they are needed, as is a zobel and thiel network. As is a miller compensation capacitor on the n-channel fet. Bad grounding can create oscillations too. Also I found out that lateral mosfets can get minor capacitive interference from the grounded heatsink. So better to use silpads instead of mica or kapton apparently.

[@gjvdspam]

Top notch vid, thank you

[@caprimen]

Just brilliant- now can you do a 1970 nad 3020

[@558vulcanxh]

Thanks for sharing 😊, really interesting 👍

[@v1970lima]

Hey, Master, we need new videos!

[@oCidadao]

Tape deck Aiwa????

[@rayc1557]

Really enjoyed part 1 of this! Thank you for the follow-up. The amp is awesome too. If played at normal listening levels with headphones, I'd love to know the temperature of the heatsink. That would give insight about the bias level. If you're so inclined, please see if there's a resistor in the output chain by which to measure the quiescent current. Am interested in knowing how far into class-A it's operating. Also, is the driver stage running open loop or, does the the output backtrack to feedback loop?

[@FirstNameLastName-tp5bu]

Did you check the RCA socket's outer diameter? It appeared that there was very little friction between the plug and socket. Just curious, wondering if it was slightly undersized...???

[@mattinwinkymg]

This thing !!? FOR HEADPHONES !!?? I swear to god if I was a stranded alien lifeform and needed to amplify signals to outer space to phone home, I would rip this thing off the counter with my speak and spell and would end up with 600 UFO's from the furthest reaches of space crashing into each other trying to rescue me.

[@तपोभूमिःश्रेष्ठम]

Mark brother!!make a repair video of Kenwood x91 double cassette auto reverse tape deck and A91 integrated stereo Amplifier,,please brother

[@bluesplayer59]

Love the music 🎉