Headphone Tube Amps - Follow-up & Tear-down
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- เผยแพร่เมื่อ 9 ธ.ค. 2015
- Due to 'popular' demand - in this video I revisit the Budget Headphone Tube Amplifiers from an earlier video - run some tests and tear them down in an attempt to discover whether the tubes are functional or just decoration. CLICK 'SHOW MORE' TO EXPAND
The NTNON Hi-Fi shop sketch: • Not The Nine O'Clock N...
My original Headphone Tube Amp Video: • Is it worth getting a ...
PLEASE DO NOT SEND ME ANY MORE LINKS TO THE TEAR-DOWN VIDEO BY EEVBLOG
Important note. I am fully aware of the tear down video by Dave at EEVBlog of one of these headphone amps, which he kindly performed to lay this matter to rest.
My first video about these headphone amps was uploaded in September 2015, a kind viewer went on to send Dave one of the amps so he could perform a professional tear-down, which he subsequently did in January 2016.
If you haven't seen Dave's video...here's a link. • EEVblog #837 - Reverse...
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Techmoan channel - Content is good. Reviews are good. Pronunciation is good. Terminology is good. Enjoyment factor, at this end, is good. So, all in all, all good. Thanks for all your hard work Mat. It is much appreciated.
Couldn't have said it any better than that.
what can you say about the comments? :D :P
I realize it's kind of off topic but do anybody know of a good site to watch newly released tv shows online ?
@Mayson Kade flixportal :D
@Korbyn Alec thank you, I went there and it seems like they got a lot of movies there :) Appreciate it !!
10:49 "Ya sorry about the breathing there, it's something that I do from time to time. I've been trying to stop, but it just seems to keep happening." Very good sir, and watching this now in 2019, you were saying tubes fine as far as I am concerned. We all have accents and if literally everyone knows what you are saying, they are just being rude. Anyways thanks for the content.
Man I love how the first 7 minutes is roasting the comment section lol
And the last 7 seconds is effectively a ‘death threat’, lol 😂
The most well-equipped high end home electronics store in my city is easily one of the least welcoming places I've ever been to. Watching that "HiFi Shop" sketch definitely reminded me of being condescended to by old dudes who were very proud of their vast knowledge that they were blessed with at birth. I appreciate your sincerity and your enthusiasm for plain speaking. Carry on, Mat!
Hi, electrical engineer here.
Gold Xuan Zu: the circuitboard is a combination of through-hole components (soldered THROUGH the circuit board, mainly on the right) and SMD components (Surface Mount Device soldered ON the circuit board mainly on the left) which is why they don't seem connected if you look on the back. It uses HQ surface-mount capacitors which filters the high/low pass frequencies and along with the tubes/valves (which act like old-school transistors) creates the analog vibe. The two IC's at the front are (digital) dual amplifiers and actually seem high grade. Generally the circuit is of very high quality and an amazing finish for a budget tube/valve amp. So no suprise on actually being better.
Zhilai: "A worthless heap of shit" as my favorite Aussie EEV-blogger likes to call them. All of the capacitors are of terrible quality and one of them is already busted (the electrolytic caps as we call them have fluids inside that swell up after time). Not worth explaining the rest. Garbage.
Little Bear: What. The. Actual. F*ck? Almost ALL of the components are obsolete/refurbished, it's a wacky mix of horizontal and vertical circuitboards probably to cram all that circuitry inside. All I see is trouble. Not much to add.
gigglygigglydude Could you comment on the new little bear b4 as I would love to see what you think of it’s internals?
Agree with all of gigglygigglydude's comments and would like to mention that a better set of tubes will probably get rid of the microphonics in the Gold Xuan Zu amp as this is a mechanical issue with the internal components of the tube.
might be wrong but it looks like they might be using a switching boost converter to jack up the voltage to run the heaters and just filtering out the noise post amplification, at least on the first two. Don't know much about tubes, but i'm not sure what else that other little smd chip could be doing. agree with giggly, xuanzo looks descent others are junk
Well, there is nothing "digital" on the Op-Amps, as it is analogue in and analogue out. Per definition, as tubes are of course analogue. First amp looks the cleanest build. Little bear components obsolete/refurbished: no, it is just the standard Chinese junk. Nothing valuable enough to salvage / refurbish. Wacky mix: I guess you never saw electronics in confined spaces before? Signed, a real electronics engineer.
gigglygigglydude Thanks so much - really appreciate the knowledge. Went and bought the amp you recommended cos I want to do my toe in the water without spending a ton. Please keep helping people with posts like this.
I loved the use of the Walkman in response to using a Pono. I actually physically laughed from that. Thumbs up.
A blast from the past. But I thought the cassette was the most intriguing thing I saw.
A good thorough layman's review (and easy video to watch too). Some times you find out they're duds. That's the point.
For the ultimate in troll, use that old stainless steel wire device. 🤣👍
Next time use a minidisc player. That will really drive the purists nuts.
With ATRAC compression turned up to max! (equiv. to about 64kbps MP3 if I recall rightly).
They'll be foaming at the mouth!
I am listening to music from TH-cam, using earphones-with-microphone, plugged into the front jack on the pc.
Na, use your Tififon!
Next time plug into a potato.
128MB Mp3 player will just do it
A few short comments (I don't like typing a lot):
In the late '60s I watched my father and uncle build hi-fi and electronics kits (Knight, Scott, Dynaco etc.)
From early to late '70s I built Heathkits and Eico, and worked in TV repair shops.
I got to the point where I can look inside a tube and identify which leads go to the anode, grid(s), cathode, heater etc.
Came in handy when the ID was rubbed off.
Never worried about leaving fingerprints on the 1000s of tubes I handled.
In fact skin oils on the higher power tubes only made a distinctive odor.
Looking in my 1973 RCA Receiving Tube Manual I see that the 6J9 is a high mu triple triode.
Doesn't list the others mentioned.
To those who like the sound of tubes I say "have at it", the added distortion is like the fungus in a good cheese.
Nicely put
The 6021 subminiature tube is a twin triode. It looks like it was high quality as it was one of those subminiature tubes that were built to US Military specs back then. It was used for RF Amplification and Oscillation.
maybe we should call youtube "youvalve" from now. :-)
And therefore at this moment I shall declare this comment by +Johan Ouweneel as the best reply for all those who paid their attention to the unrelevant on the previous video on this topic.
+Johan Ouweneel or youpipe
+Johan Ouweneel
no.
these are different "tubes". youtube is called after a tube which is not a valve.
Oh. You're just being silly.
+Silly Sad No it isn't. It is named after a cathode ray tube (as in TV) which IS a valve.
***********TEARDOWN TEARDOWN TEARDOWN TEARDOWN*********
There is a choice to make... You can either be
A) The 50th person who links to the eevblog teardown video
B) Someone who reads comments & click here th-cam.com/video/coSt5HWRvv4/w-d-xo.html
+Techmoan my only concern was the price of the units as i have a ok valve amp but the valves cost around £10 each So i couldn't see how the ones you tested were going to be much good.
+Techmoan EEVblog (David Jones) in Australia did a TH-cam technical tear-down of the gold valve amp, shown at 11:38. The valves in it are hard wired as cathode follower triodes. Thus, they have no voltage gain, but will operate on voltages as low as 12.
+Stephen Clementson so you went for option A did you?
+TheBaconWizard Dave Jones (EEVBlog) drew a circuit diagram of that amp, which showed that the valves (tubes) did not provide any amplification. Even the buffering they provided served no purpose, and it was clear that the valves could be bridged out of the circuit. Bridging the valves out would undoubtedly reduce the distortion. Not worth the cost.
Stephen Clementson Correct. So option A, then.
Also, these are multi layer circuit boards. The tracks on the bottom are only parts of the traces going to the tubes. Look carefully art the top view. There may also be traces in between layers.
I was about to comment this, but I scrolled down a bit to see if it had been mentioned. You've hit the nail right on the head.
i just want to say as a 22 y/o who is slowly getting into the HiFi scene (especially headphones), I really enjoy your videos and i find them very entertaining! I'm on a binge of watching at least 10 of your videos a day for a few days now and i have no intention of stopping. I love how in depth you go into the small things that are good and bad about each product. Also i love how you handle the haters lol. Keep making great content Matt, most of us really enjoy your time. God Bless
I'm no engineer (yet) but from what i know and can see a) all of them send the audio through the tubes, but are not necessary using them for amplification (microphonics are a clear sign the audio is going through, but the tubes could just be configured for a gain of one), b) all of them have ne5532 dual op amps, that probaply do the actual amplification.
On the gold one it seems to be pretty obviously using one on the input and one on the output, so probaply in->opamp->tubes->opamp->out, the tubes probaply have no or almost no gain, just to colour the sound. COuld be that they actually do the gain an the output opamps are just used as buffers.
There are coils and some smd chips on there, together with a bunch of caps, so that's probaply a power supply section, but as the caps are all 16 or 10V ratet it's not gonna be a step up converter, my guess would be switching step down to power heaters, so they don't generate to much heat as they would with regular linear regulators.
The silver one has only one ne5532, so only one solid state stage, the smd device at the rear is probaply a buffer for the line in. There is angain an inductor with that to220 package device stuck on the back, so again probaply voltage drop, but this time probaply just a 78xx linear regulator and the coil for filtering something, but only one this time, wich makes sense because only one tube... wich makes me wonder, why the golden would use 2 separate power supplys for the heaters, normaly you would just put them in series and power them with a higher voltage (generally 6V or so per tube on those, so 12V, wich I would guess is also the input voltage), so maybe the re is just some power filtering on the golden one, who knows...
The little bear looks really bodged together from modules, obvously the battery indicator on the rear panel, battery charger/protection on the thin part and the green module actually looks like a voltage converter, but it seems to be a step down converter from what I found, probaply again to run the heater more efficiently.
Again only one ne5532 but some damn huge capaciators, much more like in a decent, powerful audio device, so either the circuit pulls a lot of current spikes or the battery converter generates a lot of noise. Also, two of those caps seem to be nichicon, wich is one of the top brands and I would not expect those in a device as ceap and shoddy as this, so could be fake.. then again, it looks like something built by some single dude in his basement, so maybe he got genuin ones because he knew they were better... probaply not though.
About running the tubes with low voltage, while all of these are ment to be driven with 100s of volts, a lot of those small ones can operate on low voltages, even 10 and lower, but the possible output power drops significantly as well as amplification headroom, as there will be much more distortion (called operating in starved plate modey sometimes used as an effect for guitar sounds), but as a weak preamp/unity gain stage it should work
That's what came to my mind, hope im not talking bullshit
Very interesting! Thank you for your input!
Very competent analysis, grateful of your essay.
Good read. Hope you got your engineering degree.
Also, I can't help myself;
probably*
Correct, they are not doing any amplifications, thats all left up to the op-amps(NE5532), the signal is passed through however.
Even if they were used at low voltages, they would be firmly on the lower part of the gain curve where they are very unlinear.
The problem, I think, is that for some people, being angry on youtube *is* their hobby.
"You nailed it." -- seems appropriate again!
@tone167 - Sometimes the upload warrants some backlash though. Not to mention the shear number of brain-dead morons that comment. ... But one has to be selective in one's response. On uploads such as this and mostly other electronic or technical/DIY uploads, good etiquette is appropriate. But when one comes across an upload that is spouting bullshit, then one straps on the Colts, dons the poncho and flat-brimmed hat, boots and spurs, stuffs a Virginian in the gob and walks out onto the dusy street, with a determined countenance.
I'm former electrician technician from Hungary (former communist country where even the TV and radio bandwidth was different) who live who live in a USA and audio file. I'm interested in the things what I didn't see before 99% what you show. I don't care how you call it. Thank you for your hard work!
Long live communism
"...remember to enjoy yourself, it's later than you think." Very wise words, Matt.
Excellent follow up to a great video. Although strictly speaking the guitar music at 8:21 should have been on a left-handed 12 string guitar, otherwise it sounds like rubbish and is a waste of money.
😂
ROFL!
Thank you - that was a good laugh!
That is why Jimi Hendrix died when he started to play right handed.
Hey man, you can't get bent out of shape over youtube comments. you will never be able to please everyone. I think your videos are nice and a good mix of technical and plain english.
Keep doing what you do, you do it well.
I've been watching your videos for a while they are great and informative as your opinion is based on what you have in front of you. I've personally been more involved in my HiFi passion in the past years with a complete CD / Turntable setup in the living room and a vintage cassette player in the kitchen. As I was doing researches about audio equipment when I first got into HiFi, reading online and going to audio stores, I got sucked in the HiFi world / community where everybody knows best. I can't stress this enough, most people who are into HiFi are taking it way too seriously and are very opinionated. At some point, I realized most of all opinions you get from those fanatics are rubbish and I learned to appreciate the time and care people put on their setup instead of what type of brand or equipment they own. Lets face it, you dont need 20,000$ of audio equipment to appreciate music.
A lot of the HiFi enthusiasts seem to never listen to music...they just argue about the best way to listen to it. Meanwhile I'm enjoying an 8-track.
I don't need $20,000 but it sure would help...
Do what you like. Ignore the trolls.
I do what I like...but I laugh at the trolls.
Laughing at stupidity is not the smarter approach.
But its the more fun one
PlebzOr Blapparapp
Why, thank you!
many people comment part way through a video, dont realise its been said later on, and dont bother editing their comment, that or they stop watching half way, who knows, many viewers are about 16 and have never heard of a valve or anything that isnt an ipod shaped object
Hey Techmoan! I have a degree in electrical engineering and nuclear engineering, so I took a close look at all three of the devices you have here to see if I can help you out a bit. I specialized in control systems and power distribution, so this isn't *quite* my area of expertise, but I'll see if I can take a crack at this.
The IC chips that you see on the boards are NE5532 Op-Amps. It seems as if the IC's are working as a pre-amp and the signal that they output is fed to the tubes to boost the signal. I believe you refer to this as a hybrid amp.
The two-tube amp has a separate op-amp and tube for each audio channel while the single tube amp has a single, dual channel op-amp and a single, dual channel tube. The single tube is pretty much just a two-in-one solution. Either way, both amps provide stereo hybrid sound.
The pocket amp does the same thing as the others as well, but has a micro-tube and some dodgy components, leading to the lesser quality sound.
Hope this helps!
+Classical Rips Hello fellow engineer!
Indeed, there are opamps are inside each amplifier. Probably for coupling _chube_ output impedance to lower *impedance* of headphones. Choobes do amplification, opamps do coupling here, just my guess. Anyway that means they are hybrid and not cool enough and basically an abomination for a true audiophile.
No sign of poweramp (_post-amp_, really?) ICs though as they usually come with heatsink pad even for a small headphne amps. The second (blue one) has something with a heatsink on a bottom side, but probably that's a part of power circuit.
PS. CHUBE-CHUBE-CHUBE-YOUCHOOBE. Hope you forgive me for a little irony, Mat ;)
+Classical Rips yes, thanks for the info.
A pair of NE5532 (and many other) op amps are quite capable of driving stereo headphones all by themselves. The tubes are window dressing.
I built my own tube amp with pencil tubes for the fun of it. Tubes are high impedance devices while headphones are relatively low impedance. The NE 5532s are being used as the outputs as they have a high impedance input but low impedance output. The only other way to get an output from a tube that could drive most headphones would be to use an audio transformer which adds weight, complexity, and low level distortion.
Whatever you do, don't change your presenting style Matt. Love the lost format stuff and hope you wont stop once your audio and video cabinets are full. I love the fact you try stuff out, its always interesting. I have no interest in dash cams, but I haven't missed an episode! :-) Compulsive viewing.
+Paul Grimsley ive got plenty more things to show. Two large parcels turned up this evening and hopefully if the contents work they'll be used in some HiFi videos next year.
+Techmoan Excellent, Thanks for the reply Matt. I hope you continue your logical stance on audio demonstrations too, maybe with a quadrophonic a setup review! As far as I know TH-cam can't output audio in quad....? :-). All the best.
"sorry about the breathing, i try to stop but it just keeps hapening"
Ur amazing. I needed that joke today.
I hope negative comments will never discourage you from making more videos. I really enjoy your style of presenting. I learn a little with each video and you've inspired me to re-look at my hifi and think about making changes....although maybe I'll stay clear of these headphone amps ;-)
Electronics APPRENTICE/ENTHUSIAST here (I AM NOT A PROFESSIONAL), I will try my best and to keep it simple:
In order to simulate a delay, you have the following options:
1. Microcontroller or microprocessors with a special software
2. A timer IC (like a 555)
3. PTCs/NTCs that heat up over time
4. Slowly charging/discharging capacitors
Option 3 (SMD PTC/NTC) or Option 4 (multitude of caps on all boards) could apply to all of those, so I will not mention that.
Let's go through all 3 amps:
#1 @11:36 - Has an IC with a sanded surface on the left side (idk what they're trying to hide here), option 1 or 2 could apply here. The two ICs on the right side are NE5532 OpAmp-ICs (one IC contains two amplifiers, they went overkill here), but I don't think they would be enough to supply headphones. The through-hole connections on the back also look a bit weird, they usually expose some copper instead of having a solder mask. Conclusion: Probably legit.
#2 @12:16 - Also has an IC (sadly I can't read it). Only one NE5532 this time, proper through-hole connections and another IC in a TO-220 package, most likely a voltage regulator (two pins would not suffice for a stereo MOSFET). Conclusion: Legit if it outputs stereo to two different channels.
#3 @13:22 - This one is a bit weird, as it has a lot of ICs on it, half of which I don't know what they do. I guess some of them are charging/monitoring circuits for the batteries. We also got one NE5532, an XL6009E boost converter (makes lower voltage to higher voltage) to reach 12 Volts. Conclusion: I don't know, the green board looks sketchy. The white stuff on the back is just solder flux by the way, meaning unlike the other two it got actually hand-soldered.
tl;dr: They could all be legit and I think they are. I need some help.
To clear some myths: Tubes and their sockets have form-factors. They don't use all of their pins because they don't need them, most pins probably aren't even connected internally.
+NKN1396 "An excellent comment"™
+NKN1396
#1 Yeah the hair rose up on my neck.
#2 Agreed.
#3 See #1.
+Yu Lei I'm crying with laughter reminiscing about all the Chef Excellence shit. God, I miss Ashens. I'm going to head over there now.
Is life real ,or is it just shadows on a cave wall?
+NKN1396 And you forgot valves. The grid needs to be heated to emit electrons.
So it DOES take time at the beginning.
Great videos. I love these meta ones as well. Kudos to you for responding to all sorts of comments and not just ignoring them all as the rabble they may well be. TH-cam is a rough place to find respect, but you certainly deserve a helping or two for your approach.
First time to your channel and your feedback on the comments is exceptional and the amount of detail and effort gone into them is what most people need to do. It’s great because anyone who doesn’t have a chip on their shoulders or will actually watch the video in its entirety before making a comment should appreciate your effort in trying to share an interest and that’s it.
Welcome to audiophile land. You'll hear from people admonishing you for not polishing your tubes, or how you muststoring them in a freezer when not in use. While I know the actual proper way to use tuvbes is to have pure clear quartz rock crystal the, each weiging 25 grams apiece (very critical) 120 degrees apart Exactly 25 mm from each tube. Otherwise, the sound doesn't reflect properly, and you'll get listening fatigue. And forget about it is you use anything but a Zinc carbon battery to power them. Lithium batteries introduce serious temporal distortion
LOL - Temporal distortion. Excellent comment!
Mine are positioned on ley lines. No one serious about their audio would do a review without mentioning this. ;-)
Don't forget to polish nice and hard your mpingo woodie ,shunmook wouldn't have any other way.
not gonna lie you had me going for a second thumbs up to your comment.
OMG - You need to elevate your interconnect and power cables off of the desk at least 3 inches and at least 90% of the run aligned parallel with the equator.
The tubes are actually being used; 12 volts plate voltage is enough to run many miniature tubes in a "starved anode" configuration. That said, most of the gain is provided by the 5532 low noise op amp; the boost converter is generating the voltage for the IC, not the tube. The same circuit without the tube section would work just as well.
I'm have EE background myself and always enjoyed your presentation method. Learned a lot from your videos.
Layman's terms or understandable words is best communication for general public.
Just do what you're comfortable with.
We subscribed due to that.
I'd turn away if your presentation was too technical.
Your videos are great. As a Canadian, your terminology sounds completely fine to me, including the word 'Tube'. I'm quite glad you skim over some of the technical discussions; I already know about matched impedence, what the mpeg-1 format is, and how CDs work; if not, I can always pause the video and spend sometime to look it up. To get a lesson on all that again in-video though would likely bore me, and sometimes I do skip chunks of your videos as a result. What I'm really here for is the same reason you enjoy making these videos -- playing with gadgets, technology, and all-around curiosity.
Audiophiles spend a ton of money and time trying to get the very best audio experience, even if it is often a placebo or a matter of taste. Inherently, those types of people are naturally anal retentive. I wouldn't let them get to you; your videos are great and I highly enjoy them.
Bonus tip, though, always make sure to keep the plate axis of your tubes aligned with the Earth's magnetic field for extra audiophile quality. 👍 👌
If you don't have £30 000 cables, you can straight out forget enjoying music.
The "Don't switch them on, TAKE THEM APART!" comment is actually a popular phrase that Dave from EEVBlog uses.
+ChillCosmos All to often, tech products come with a "Disassembling, reverse engineering, or tinkering with this product is prohibited" warning. This is so bad, it stifles innovation. How much of today's technology would exist if someone in the past had not disassembled, reversed engineered, or tinkered with their electronics? Louis Fender got ideas for his guitar amps by studying old radios and electronics manuals. His Champ was supposedly a modified circuit from a Western Electric tube manual. And his amps were studied, copied, and modified by just about every amp maker since.
+Doug Browning I don't think anyone that would want to take something apart to reverse engineer it would pay attention to such a warning. It's not like they are going to come to your house and throw you in jail for taking it apart. I don't think simply having such a warning on it "stifles innovation" at all. They are mostly only there to stop people that don't know what they are doing from electrocuting themselves anyhow.
+Kandi Gloss I think it may have more to do with the fact that a lot of tech today includes embedded software. Tinkering with that stuff can get your device brick-housed, and you may even be in trouble with the copyright police. However, most of today's programmers learned from examining somebody else's code. I don't think there's a programmer alive who can say they didn't play with an Apple II or similar system when they were kids. In the old days the warnings just pointed out that there were dangerous voltages inside the product, and often refereed to no user serviceable parts, and that you should take it to a qualified technician for service, TVs also added warnings about CRT implosion and x-ray exposure risks, but never actually prohibited users from tinkering with them. What you do with your own property should be your own business.
Try telling Big Clive not to disassemble, tinker or reverse engineer, and you could guess how obedient he would be. If he obeyed, there'd be no bigclivedotcom on MeValve.
Actually, EEVBlog did a reverse engineering to one of these amps, and "The tubes! They do nothing!" (almost): th-cam.com/video/coSt5HWRvv4/w-d-xo.html
Dear Techmoan. The thing that drew me to your channel was your excellent reviews of retro kit from the 70's and 80's. Little did I know that when I subscribed to your channel (which I did very quickly incidentally, after watching just two of your videos) I would be getting videos like this as well! Videos like this (and those brilliant the muppets videos), are pure gold and really do make me laugh very much indeed. Keep these up please, they are absolutely priceless - and of course, keep laughing at those trolls.
I 2nd that. Great video ol boy. God save the queen and all that..LOL
Hear ear
@@woodysgeekchannel2204 - I'll third that.... But fuck the Queen... (figuratively), monarchy is long passed its used by date. (I'm a British anti-monarchist btw....).
Excellent comment *Alan J Woodward* - My sentiments entirely. And you gotta love those two muppet Dudes.
I'm just a southern boy in the US and found your videos very informative and your accent pleasing, piss on those who criticize on detail and being politically correct. Most of the comments I read just shows that some folks have no electrical/technical background but yet insist on commenting about something they know nothing about. Funny how kids these days can search the internet for anything and still learn nothing.
Techmoan, I think you are doing great. I like it that you explain things for the layman who would be lost with all the technobabel. Your videos are very informative and entertaining. I've learned a lot from watching your channel. Keep up the great work.
The 6N11 is a Chinese version of the 6DJ8/ECC88. It is a twin triode (three electrodes, cathode, grid, and plate; similar to the collector, emitter, and base of a transistor) originally developed as an RF amplifier for TV receivers. It is a nine pin miniature tube. The pins used are 3 and 8, cathodes; 2 and 7, grids; 1 and 6, plates; 9, internal shield; and 4 and 5, heater.
The 6J9 is a triple triode, 10 pin miniature tube, originally used as an RF amp, oscillator, and mixer in FM radio receivers. It's pins are 3 and 10, cathodes; 2, 9, and 7, grids; 1, 6, and 8, plates; and 4 and 5, heater.
The 6021 is an eight pigtail sub-miniature industrial twin triode used as an RF amp and oscillator. It's pigtails are 5 and 4, cathode; 7 and 2, grids; 8 and 1, plates; and 6 and 3, heater.
I have no idea why they are using VHF RF tubes as audio headphone amplifiers, where audio tubes like the 12AX7/ECC83 would be more appropriate. I also have no idea what the ICs are for in those units, as the tubes alone should suffice in this application just as they did in the 1950's-60's.
+Doug Browning Old surplus stuff. Personally, RF tubes always sound narrow.
Any chance we can measure heater voltages?
+Don Petrik All three tube types use 6.3 volt heaters.
6DJ8 - plate = 90V, grid = -1.3V, amplification factor = 33
6J9 - plate = 125V, grid = -1.0V, amplification factor = 57
6021 - plate = 100V, grid = -6.5V, amplification factor = 35
(all ratings per section)
+Doug Browning
"measure"
On paper is fine, what are we getting in the device for real? (measured heater current under load would be even better lol)
The ICs are mostly likely being used to generate clock signals to boost voltage from that battery through that 6800 uF capacitor. Think Dickson voltage doubler. That's likely how a 12 volt power supply or that rechargeable battery can achieve enough voltage to push a tube.
+Doug Browning A lot of the headphone amp designs I've seen tend to pass the signal through the tube, then use solid-state components to provide the final drive current to the relatively low impedance headphones. Most tubes have fairly high output impedance, unless you're using a cathode follower...
This man is an excellent communicator and thank you for sharing your knowledge with us my friend
Techmoan, I just want to say thanks for your reviews, I realy enjoy watching your channel. I discovered your videos a month ago and all I can say is you're doing a great job. Your reviews are well balanced, they contain a little bit of history, prices, estethics apretiations, technical specs, testing, and the mosts important thing: your conclutions. If I can make a suggest, it will be: dont waste time in some useless people that is always around. Keep like this, sorry for my english, Im from argentina :-)
Hi, I would like to thank you for all your efforts to provide an informative, and high quality videos for everyone .. Keep up the good job!
I really like this reply video. Super sassy replies, that were well deserved. A lot of people that never become fully invested in X hobby, are steered from the experience because of other enthusiasts. Specifically, the ones that chastise others for things like terminology, knowledge and questions about said hobby/interest. Just stop. We get it. You're awesome.
Dear Techmoan thank you for your great videos first of all. Addressing your questions - those tubes seem to be a part of the electric circuit and sound signal path. Circuit boards are double sided so you should not be confused with the fact that some of the pins are not connected on the one side. Whats a little bit disappointing is that the actual amplification is performed by an operational amplifiers and not the tubes, which are most likely connected as a cathode followers. Making a long story short - tubes are part of the signal chain but mostly for decoration and I would say marketing purposes (besides adding a little bit of distortion). You may find true full-tube devices with a higher price tag.
Matt your videos are pure gold.. Platinum even. Love this stuff and the sense of humor is priceless thanks.
I really love your videos and your passion for audio. I always find myself searching the web after seeing something cool that you demonstrate
i like your walkman cassette player.
thats a pretty nice vintage piece there.
Probably couldn't get his hands on a gramophone :P
People often display a lack of civility on the Internet that they would never consider doing face-to-face.
+Milosz Ostrow Yes, quite indeed. My favorite ones are:
1. My generation sucks/living in the wrong era
2. General snobbism about music, genre etc. Closemindedness.
3. Being rude to people who give free tutorials that they don't provide the info fast enough because they speak.
4. Thinking there opinion is a rule, not a matter of preference or viewpoint.
5. The bad kind of trolls who just want to be rude and impolite.
6. The people who think everything needs a label and that everybody who doesn't know what it means is a donkey.
7. The ones that have good info but brought by very, very , very angry people because someone made a mistake (we're all human)
8. The grammer nazi's who like to exterminate the ones that can't grammer.
9. The ones that just talk nonense with meme's/hypes like the whole lizard thing.
10. The ones that ask for attention (DOES ANYONE LIKE THIS IN 2015)...
11. The people that think this has something to do with something that somewhere in their lives and tell a very long story what ends in a beg for attention.
I think I've got all that I think of....
+Jelte Derksen You've just described just about everyone on Facebook.
+Milosz Ostrow Of course they wouldn't do it face-to-face, they would be to afraid they would get there teeth kicked in, and rightly so.
+Jelte Derksen I was born in the wrong generation. Vinyl is the only way to really listen to music. Techmoan needs to talk faster. My opinion is fact. Fuck you. Everything needs labels. Actually you're not supposed to touch the tubes, goddammit Techmoan you piece of shit. *Grammar.
Hissssssssss. DAE LIKE TH-cam VIDEOS IN 2016? Once upon a time, some relevant stuff happened, so like my comment.
+Milosz Ostrow I have found the opposite to be true as well, really, just like anywhere there are dicks and there are decent people. Just on the internet the dicks might be decent people irl and the decent people might be dicks.
Came in for the follow up, was immediately reeled in by the sharp, dry wit of the opening few minutes. Love your videos!
I’m glad you brought up those comments. Some people take these things way too seriously. Keep doing what you’re doing and have a great time doing it. You make great videos, you’re having fun, and there’s lots of us who really enjoy viewing your creations. Thanks.
Your dry sense of humour and your love for electrical oddities are the reasons that keep me coming back to your great channel. A regular viewer from Austria (maybe the only one from there)!
+Uli Mativ Nicht der Einzige nein ;-)
Great video as usual. There isn't a video on TH-cam that doesn't get trolled or hated on in some way, please just keep producing great content and ignore the uninformed masses that comment before they have even watched the whole thing...
Hey Techmoan, Love your videos! I never knew such things exist before :) Keep up the awesome work !!
I, like many others, saw your original value amp comparo and thought it was great. I loved the fact that you took the time to address many of the comments. I hope you don't let the negative comments bother you too much. Just do what you do best and let the trolls vent. I'm sure it's therapeutic and hopefully they feel better for it. And having lived in England for a number of years back in the 80's, I appreciate the more elegant and straight-forward way the Brits use language so please don't change that.
Thanks for your efforts. I appreciate it. Subscribed.
LMAO. I love it. Tubes vs Valve. finger nails, touch vs don't touch. Priceless really priceless. You are always entertaining no matter what you talk about. Keep up the great work I really do appreciate all the hard work you put into these videos. -John
The PCB's are double sided and it seems that some of the tube pins are connected to components on the top side.
Preamp tubes like these are often used with low plate voltage in guitar distortion stomp boxes and some cheaper microphone preamplifiers, the operation mode is called "voltage sagged" and can work alright, although most of the magic happens at way higher voltages as seen in properly designed preamplifiers. The "Little Dot mkIII" is a very popular and well sounding all-tube headphone preamplifier.
The opamps are there to buffer the signal, tubes are high impedance devices.
Søren Hammer In fact they behave similar to FETs.
I love my mk lll!
These amps may have one or more voltage multiplier stages, my electronics knowledge isn't really good enough to tell, but the "gold" amp certainly has enough components on the board for that... a ditto on the double-sided board, and the amps may have more layers than that - PC's now operate with motherboards in the five to seven layer range!
So they look cool! :D
There are two types of amplification - voltage amplification and current amplification. The tubes amplifies current. They are NOT eye candy.
Mate I think you should stop obsessing over the TH-cam comments
You can't make 100,000 people happy at once.
Most of us love your content and don't care about a silly mispronunciation or whatnot.
Sam Roberts eh, but but he wasn't seeking out the bad or anything, for that video the majority of comments really were cancerous
Comments seem to be blocked there now. That's probably a Very Good Thing to do, given the sample shown here.
While I agree, I actually found the teardown of the comments in this one very enjoyable. If he did that all the time it would get tiresome, but every once in a long while it's kind of nice.
I honestly really enjoyed him addressing the comments
@@RWBHere - Indeed.
As far as powering the tube, the current required is low, so these circuits can use a step-up ("buck") converter to raise the voltage from 12V. [Edit: confirmed; the tube is powered at 190V with a 6.3V heater]. The heater (a second circuit that powers the tube) is typically 6 or 12V, AC or DC, so good to go there. Finally, there is also the "Starved Plate" design where you don't run the tube at the highest voltage possible, but use a lower one. This can reduce noise and lead to extended tube life, although these small-signal tubes last a very long time (10,000 hours is typical). The Blue LEDs are somewhat bling-y, although the Chinese love an excess of bling, so to them it's probably minimally decorative rather than over the top as it might be seen in the West. There are diodes in the circuit, so the LED may simply be in place of a diode in the circuit that does not light up. In other words, possibly not useless as far as the circuit operation goes. I'm not suggesting these offer good, or even adequate performance; they are very cheaply made and little effort is made to increase or even address fidelity. Novelty items, but neat if you like that kind of thing.
Thank you for making this video and your other videos. Keep up the great work.
I'm an audio engineer by profession. I have to laugh at these hi-fi guys. It's very much all snake oil and suffers from opinion riding over physics. Take a look in a professional recording studio. There's no gold plated connectors or £1200 IEC power cables there.. Keep up the great videos pal and thanks for your efforts..
+Andrew Kirkby I'm not a professional anything, but I quite like to do my own automotive work. 1) I find a sense of pride fixing my vehicle, 2) It's old and needs it often, so it saves me money, and 3) It's hard to find a garage that doesn't break more parts than it fixes. That being said... I hear people give me all kinds of vehicle advice, and much of it is snake oil as well. Telling me to put in additives and "HIGH POWER" spark plugs, telling me I should buy this or that to make the car work better. The truth is regular factory maintenance is what's important, no amount of snake oil will do a lick of difference.
+Jesse Crandle It's so true. Some things do alter your perception of sound but most listeners wouldn't know the difference and often those who say they had a better sounding system after an expensive upgrade have fallen short of the placebo effect to a degree.. I have a similar feeling about car repair. I do a lot of my own and tend to use manufacturer's recommended parts because that's what the vehicle was tested with and will likely get the performance I paid for when I bought it but adding expensive engine health additives etc will just burn the money you spent on them. A haynes guide to save the labour cost and a trip to a parts site like lings honda for instance is my robust solution... Unless the clutch goes.
Andrew Kirkby Best investment I've made in audio is a pair of Grado headphones. I had some SR80s, but after they broke I went to SR225s. The SR80s were a little lackluster in bass, so I went to the SR225s which has quite a bit more. A pleasant bonus was I could actually tell they were noticeably cleaner sounding, and the SR80s were already pretty impressive (coming from just sad Sony headphones that were 30 bucks, whatever you find online and in stores for less than $50).
+Andrew Kirkby I bet you guys don't even use an atomic, gps compensated clock for your 50hz/60hz AC line conditioner, do you?
Stop trolling him :p
I swear you're the only youtuber I really fully watch because you provide an archival style into electronics. I'm still trying to release my new album on Minidisc, currently! XD
Haha I love the beginning of the video with all the corrections! I love your sarcasm, I hope you had fun with the whole video
I like the cut of your jib. The polite sarcasm you employ is a perfect retort to the nonsense people spout in YT comments.
Try not to feed the trolls, most of the people that complain don't even upload any videos them self's. I think you do a great job in your videos and what people have got to remember you are a one man band and do it for a hobby and never claim to be a professional. That's my 2 pence.
I enjoy watching your videos. I grew up with tubes, and I don't know anything about tube theory either. But, I did have a tube amplifier, a Fender twin reverb that constantly crackled and spit. I gave it to my brother in law who plugged it in and left it running for a week. Now it is fine. No criticisms, just enjoy what you do.
I absolutely love your videos and your attitude mate, don't bother responding to comments unless it's a legitimate question or something. Keep up the good work.
You can only please some of the people some of the time. Keep up the great work, please continue with the common speak and the accent is part of the charm in the video. Please do continue to have a great time with your hobby!
great video, keep doing what you are doing, what do you think about minidiscs? I am surprised you haven't mentioned them at all as a discontinued device
I'm an electrical engineer so maybe I can clear a few things up.
Low voltage isn't an issue here. See all the capacitors (labeled 16V)? (There is also an inductor.) Those are for a boost converter. Boost converters allow you to raise the voltage of DC with some tricks from AC electronics design.
The circuit boards in those amps were double sided. So even though only a few of the traces are visible from the bottom of the board, on the top layer there are connections to the other pins.
Please be careful with open tube amps because they utilize high voltages. The capacitors can retain the voltage after the device is powered down.
Thanks for all the great videos! This is my favorite TH-cam channel.
I'm glad you went back and called out everybody that didn't pay attention and all the snobs. Love your content. I have no problems with anything youve done or will do. Keep it all up.
These people are " nit picking " I'm in detroit Michigan and have NEVER had any issue listening to, comprehending, or understand your videos! Keep up the great reviews!!
Ah.... But that is because Matt tends to monitor his demographics and chooses to use the word 'Choob' instead of *valve* accordingly.
It's because those who complain here are from Grosse Pointe
TH-cam comment sections are almost always full of junk. But you said your original video even had an intelligent discussion, so that's great! You should probably heed your own advice from the end of the video and don't get too upset about all those comments. There will always be haters, stupid people, and those with a short attention span. No wonder the term "TL;DR" is pretty popular these days.
I know taking criticism is hard. But it's even harder if one also takes to heart stupidity or lack of attention that is not really criticism. Sometimes it's neither, but just a serious question that meant no harm.
Don't worry, your videos are great. They're on a professional level. I like every single one, even when they are about cameras that don't really interest me. They're still fun to watch.
Continue what you do. Me and your thumbs up/down ratio are telling you you're doing it right :) Thanks!
I know I am years too late here. But can I just applaud you for getting TH-cam Music Library music onto a cassette? Because that is absolutely fantastic.
"Because its later than you think" Thats deep man. Love the videos!
6N11 and 6J9 are low noise amplifier tubes. The serials are Chinese variants in Europe the 6N11 is an EC88, and the 6J9 is a variant of a 12AU7 also a low noise amplifier. In my first valve amp, a CR Developments Kalypso 12AU7s were used as pre amplifier tubes, the power amplifier valves were EL84 - the big box(es) on valve amps are normally power transformers to drive the heaters in the valves. The Kalypso only produced 15watts total output which is why I used Triangle Comete loud spears with high impedance (I think they were around 96db) to get the best out of the amp. That was back in 1995. I was lucky to come across a pair of Quad valve amps from the 40's (which I had reconditioned) they used 500B power amp valves and were gorgeous. These were produced before the transistor was perfected in 1947. So yes Valves/tubes do work. They sound awesome though do 'colour' the sound, which I don't mind, I'm not that much of a purist, I like the warm tube sound.
Tube amps typically have an impedance transformer to step the impedance down from thousands of ohms at the plate of the tube to around 8 ohms for the speakers. At high power levels these transformers get large, heavy, and expensive to make.
You tell-em mate. Me personally I enjoy your videos. Keep them coming. Cheers
Thanks for all the great videos. I enjoy them very much. Keep doing what you do.
I'm not an engineer or particularly knowledgeable on electronics. I enjoy the general videos from Techmoan quite a bit. I also sometime enjoy videos that discuss things in a more technical way, although my level of understanding varies. These two things aren't in competition with each other, they go along with one another quite nicely.
Mat makes a good point about the importance of fun, that's a healthy reminder that I need every once in a while.
I think the stupidest thing about those comments is the Americans correcting a well spoken English person about his English pronunciation. The English language in America has changed from the original English in a lot of ways, for better and worse but in typical fashion there are many Americans who have no idea what they're talking about and think that just about everything in the world comes from there.
English “person”
I really enjoy these comment answering videos...
The first amp has two ne5532p chips. Those seem to be common on headphone amps of all types. I just built one using two of those with no tubes.The second one only has one. What I find interesting is the amp that you said sounded the best uses two of the NE5532P chips and has the cleanest board. The other two only use one chip.
Are they running as stereo one amp per channel or chained together ?
Great, and thank you for the sincere comments!
Techmoan, thank you for your excellent work, it is look like the whole TV team is behind your work.
The thing with fingerprints is that the acid in the grease etches the thin glass thus weakens it and it can then crack,
however, that is only valid on high power bulbs like Xenon headlight for cars where the rapid heatening may crack the glass where it's weakened.
For tubes it does not matter due to it's thick glass and slow warming up, the grease does effect and tends to remove the usual white printning though, as moist also will do.
+senohpi Acid in the finger oils? Now that's a new one to me. Would have to be some seriously acidic stuff to etch glass... :D
Now grease stains do have an effect on halogen bulbs and the like, but it's caused by the greasy spots heating up significantly more than the surrounding areas.
+MosoKaiser Only if he`s an alien )
While why fingerprints on bulbs is bad, your theory is incorrect. In halogen bulbs and Xenon bulbs, fingerprints prevent proper cooling of filaments and cause them to prematurely burn out. It has nothing to do with glass expanding or contracting, and more to do with heat dissipation. I've burned out bulbs on purpose as a demonstration, never had the glass fail as a result of fingerprints.
+Richard Stifle just to be clear, I understand you do agree that the fact remains fingerprints have no effect on the sort of low power diode and triode tubes used in home stereo systems.
Fingerprints do affect tubes that get incredibly hot, but not low temperature tubes found in these audio amplifiers and old TVs.
+senohpi You are right guys, i certainly mixed things up :)Regarding the halogen bulbs i suspect that the grease acts as a dark or reflective spot for a certain amount of the spectral energy that the filament emits, halogen have of course a very different distribution of the spectral energy than, for example the sun, has,thus gives insuffiecient cooling on that part where the grease is applied.Does it sound reasonable?.. i have to get a bunch of bulbs and do some experiments now :)
Ive been watching your shows for years now and I only managed to see this one now (thats COVID-19 lockdown for you). TH-cam comments, for some strange reason, can be particularly nasty and i've seen some of the unkindest things mentioned in the posts. I have always felt a bit of pity for the youtube creators putting the effort they do into these videos (and theres a lot that goes into it!) only for some 12 year old to tear it apart.
Dude your shows are great! Never change them :)
Oh and when it comes to audiophiles your'e opening a pandora's box. As a sound engineer I take a pretty pragmatic approach to audio, there are no rules to all this, even the noisiest pre-amp serves its purpose somewhere. Life is just too short to over think this all :D
Really enjoy your videos. And I like that you use terms that anyone can understand. Keep it up.
Many years ago, I had an old consul stereo, she was cheap but the speakers were from an older consul and they were great quality. One day I was at an auction sale, and I purchased a Heathkit stereo receiver. She had dozens of tubes and I really wanted to know how it sounded, it must have been twenty years old back then. So I run the wires from the consul up to the amp, hooked up the record player which was a junker Gerard with changer, and played a few records. MAN what a difference! Those tubes changed an average consul stereo to almost BEING there! I loved it. It remained sitting atop that old consul stereo till my kids knocked the whole thing over roughhousing in the rec room in the basement where it lived.
You are a legend.. Keep posting videos in the great British way!
Your sense of humour cracks me up! You could be talking about a block of cheese and I'd still be entertained!
Keep doing what your doing and have a nice Christmas 😀
+GRUSS Newton Oh man... techmoan cheese reviews. I'd watch it, I love cheese...
You´re having a great channel! Just keep doing what you do.
You really inspired me to start experimenting more with my hifi setup. Before i watched you i would never put a cheap Chinese thing like that in my hifi and now i did. I bough one of those cheap 6j1 kits on aliexpress, i replaced the tubes with better ones and put some brand name capacitors in it. I use it with my cd player that i always thought sounded too bright, now it sounds a bit richer.
I love the rants you have at the beginning of some of your videos. Hilarious stuff, lol
"it's later than you think" I like that, thanks.
Matt, your delivery is fine and your channel is a pleasure to watch. As a fellow 'old-skool' - retro hifi buff, I find your uploads a breath of fresh air and always engaging as is your typically Brit dry witt (much like *John Ward's* channel). It is to your credit that you take these assinine comments in your stride. KEEP UP THE GREAT WORK.
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Tech bit....
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In the XuanGold - The two 6J9 'thermionic valves' (or 'electron vacuum tubes') are triple triodes - More at home in a receiver (local oscillator/RF detector/mixer). Here probably being used as a two stage class A amplifier (on each channel). The op-amps being either input buffers or output power amps It is entirely possibly, that one of the triodes (out of the three in each valve...) would be redundant, hence the pin-outs not being connected to the circuit traces (which is common in valve/tube technology) and might even be the cause of the microphonics.
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The silver Zhilai - single valve/tube - 6N11 is a double triode. Being used in a similar hybrid configuration. but using one valve/tube shared across two channels, which coupled with inferior electrolytics, would explain the inferior/mundane performance compared to the former XuanGold.
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The Little Bear - Uses the 6021, a subminiature double triode. Most likely using a similar circuit configuration to the Zhilai. These Raytheon subminiature valve/tubes are designed specifically for harsh environments (military spec). Ironically, probably better specs than the previous valve types and appropriately employed in this 'mobile' headphone amp. The hiss audible, might be simply down to either inferior capacitors, poor soldering (likely), duff components (resistors), low quality op-amps, or a combination of all.
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High grade military electronic equipment of the WW2 and the Cold War used similar sub-miniature electron tube technology (I've worked on many such devices), where space (in a military aircraft, ship or tank) is at a premium and efficiency is paramount. Those early pre-transistor 'walkie-talkies' used in the latter years of WW2 contained such devices, whereby the tubes were soldered in place and suspended in rubber glands, to minimise shock.
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As always, like with climate science denial and politics, there are always those that try to find a conspiracy in everything. Whilst I concede that conspiracies do exist (9/11 being the obvious prime candidate...), I think it is likely a very American thing, to suggest that the Chinese would design and build a 'faux valve amp'. A totally absurd notion, but hardly surprising given their abhorrence to Chinese goods and their country's ongoing, but equally absurd 'trade war'. [smh].
I have a Chinese built 18 watt valve amplifier, that I use for my guitar in my studio. It is designed around the famous Marshall amp of similar wattage and is simply quite superb (at a fraction of the cost of the Marshall item). The standard of circuitry is high quality and the bottles (valves/tube) are exactly what one would find in a British valve amp of similar design. It has a spring reverb circuit and built-in speaker attenuator. With Pentode/triode switching. It even has (foot) switchable twin channels, a line output and effects loop built in. All encased in a robust steel chassis and enclosure. All for less than £300. Streets ahead of any contemporary brands.
I prefer a tube/valve guitar amplifier. Never really considered one for just headphones. Thats audiophilia on a whole different level. Wow. Great video as always.
Thanks for uploading this video to YouChoob!
The circuits look legit from a first look.
The NE5532 chips look to be used as pre-amps before the valves, all the electronics seem to be fully analog from what is shown making a dummy delay circuit unlikely, the small surface mounted chips look like part of the DC-DC step up converters as valves generally need a high voltage to operate. There are exceptions to this of course.
I agree hobbies are for enjoying, tinkering with electronics and computers is very much fun for me. Good to see you don't worry about the Ellettest numptees, I tend to find such individuals amusing.
This video definitely got my subscription. Thanks for making these videos!
This is seriously entertaining, you should do this with all your videos.
That "The NTNON Hi-Fi shop sketch" was halerious!!!!
You have the patience of a Saint and some people need to get a live...
My mom says that patience is the virtue of saints...
wonderful job Techmoan!!! your vídeos are amazing
I love your response to the comments. I 100% agree with you on what your said! Loving this channel more and more