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+Mr Carlson's Lab Whats a "space charge" tube??

+Jack neff Hi Jack. Space charge tubes were used in equipment when no high voltage was present (IE: late 50's car radios.) They use the space charge grid principal to accelerate electrons at low plate potential. They differ a little in operation from a normal tube... EG: The control grid is is positively charged to act as an accelerator grid. The screen grid is where you feed your signal to be amplified. The suppressor grid (if any) in some applications is also positively charged. The tube 12K5 comes to mind.

+Mr Carlson's Lab China needs to start making space charge tubes again if they are going to make things like this instead of sticking random tubes in a random circuit.

I agree!

Unless...no...they wouldn't...of course they would, it's China, the home of cheap and electrocuting electrical ;-; *unboxes new amp wall wart, reads back* Class I Power Adapter Input: 100 - 240VAC 0.2A Output: 200VDC 0.1A

+jjensen2492 and cycle through RGB heh

+transistortester Ikr? Plus being the color blue, makes it look like a dyeing tube lol!

I agree, nothing like the soft glow of those tubes. blue...what the hell is blue doing in a tube? i grew up around that stuff. my dad was always fiddling around with that stuff. he was pretty good at it. i wish I had his collection of radio tubes and amps.

+Travis Piper Yeah, last time I saw tubes glowing blue it was a set of four EL34s experiencing The Who at extreme volume. The audience were happy but the tubes weren't.

+transistortester fully agree, seeing a blue led under any kind of tube makes me very sad. It's not anger anymore, just disappointment in humanity.

i have one also and totally agree! its noticeable to soundstage. this review just talk about electric thing but amplifier is about sound.

Subjectivist audiophiles just LOVE not talking about noise, distortion, etc. (IOW, objectively determining how good something is). It's all about using purely subjective terms like "soundstage", one of the favored buzzwords.

+neil huband Nope, she is many things, but a skookum choocher she ain't.

digitalradiohacker right into the art bin

+JinzoDefiler yeah, I'm an engineer myself (CNC programmer/operator), so I find some of his videos interesting. I do wish he'd do a couple more in depth power tool teardown reviews, not seen one for a while.. +AvE if you're listening? ;-)

+neil huband NEED MOAR BOLTR!

+Bindo yeah, +AvE ! we need moar of teh BOLTR! He's not done an in depth tool review for ages now. That was the main reason that I subbed to his channel. I miss them. :-/

+MattExzy Well, using FLAC is not that stupid. You typically won't hear the difference, but when MP3 is used with a high compression rate, definitely will. You normaly don't run into space problems on your hard drive nowadays, so I see no point in not using loss less compression formats like FLAC. No need to say that oxygen free cables are ridiculous.

+MattExzy Sunk costs need some kind of justification. I cannot believe he actually insisted it sounded better though. Belief is a hell of a drug.

I had a long conversation once with some folks who SWORE that there's a difference in audio quality between FLAC, Apple Lossless, and Wave. I even encoded a source file into each, then back into raw PCM samples, and ran a binary compare on the result. The (totally unsurprising) result: 0 differences encountered. "Well, *I* heard a difference." sigh.... You can't save everyone.

+as df You missed the point... This guy converted MP3 to FLAC...

***** Yeah I know - that's my point.

Harlequin314159 They put a lot into it 😂

Hilarious.

+NatureAndTech But at least, it doesn't have an output transformer...

+AltMarc adding a transformer will significantly reduce any static noise.

+NatureAndTech I find the best bit being the tube in the "Tube Amp" is actually removing amplification.

+NatureAndTech They heat up the room too.

+Ivan Taranov "Where's the Beef?", That's a few years back.

I disagree tubes are best all the way around. I remember even an AM radio with tubes the sound sounded like stereo. Not the all American 5 tube radios I mean Atwater Kent and Zenith radios. they mainly used 6V6 or 6F6 amplifier tubes, even the rectifier made the sound better. The youth of the 80's and beyond havent heard the real Hi Fi sound only tubes can produce. I had an Admiral Record Player that used 2 6aq5's and one 12ax7 and a 5y3 rectifier and the sound was outstanding especailly when I used a 10inch woofer from an old B and W TV set. Tubes rule in good HI FI audio.

@@ronb6182 No Ron B, it's because the music was better then. ;-)

@@j.w.8663 the music is the same same songs we are talking about fidelity. I have and played the same records on both type of amplifiers and tubes win every time. Even the rock song seasons in the sun sounds better on a dynaco amplifier than on modern stereo equipment. My friend listens to rock music I don't as a general rule. I may have a handful of popular tunes I like but my main is classical music. Big band music was what I grew up listen to when I was young, I had a few years listening to 50's rock when I stayed at my birth mothers house but when I was really young like 3 years old my adopted parents listened to big band music. The classical music came into my life when I was 7 years old when I started piano lessons. I agree the over the air music was better then because you had a choice what type of music to listen to. The old Atwater Kent radio could pick up stations all over the country on AM. The tv antenna was also used for my radio I just used one side of the 300 ohm twin lead line. I don't remember grounding the radio. AM today has nothing to offer. You can get choices on the internet like you could over the air in the 70's. I haven't tried cds on my tube amplifiers yet because I need to recap my equipment, I just aquired a varac that my work gave me for helping unload a storage hanger at the local airport. He said he used the varac when he repaired tvs and radios.i will try it on some of my tube amps. I would never run on 125 volts the tubes need 110 volts for that was the voltage back then. I believe the best of both worlds will sound good. I will post later when I hook my cd player to the tube amps I will also try my computer sound on the tube amplifiers as well. They sell headphone tube amps on amazon and ebay, but I don't have that kind of money to spend.

Tubes/Valves adds presence to recordings, mainly because of even harmonics and soft clipping! Guitarists like overtones like the octave 5th’s , minor 7th’s etc - physco acoustics, Fourier analysis, Taylor series, mathematics way beyond my uni days!

That is one thing I dislike about Windows and many of the drivers as there are so many forms of electronic distortion that can easily be added by the software drivers, if I wanted my audio to sound like it was music out of a well I would buy the cheapest speakers.

But even all solid state amps sound different from one another, so in effect they are all adding coloration to the 'original' sound.

+dogastus Now that would have been very revealing and a good indication of performance with a 24v potential.

+dogastus what would be the difference?

+Son of a Zombie It would give an indication of frequency response. Rounded slanted edges would indicate an HF roll off, sloping top and bottom would indicate LF roll off. Any ringing on the edges would indicate poor phase response and/or marginal stability.

+dogastus I wish he would have done a frequency sweep!

cbbuntz: "+dogastus That dual opamp thing looks like a stability nightmare." No. That is not an uncommon circuit configuration.

+Runar Damnes yea, but this EF80 alikes aren´t made to operate at low plate voltages

+TubiCal  EF183 will work down to 20V or so. Not sure about the EF80.

they don't? people read the title or skipped ahead

valves do have a different sound by them selves if used in a old school full valve job running at the full 160v with the beefed up components but as a hybrid its a wanking matirial just to say u got valves. I reckon valve should stick with valves and silicon should stick with silicon.

+John Ridley Agreed. I was hoping he'd just go ahead and jump grid to cathode across the missing tube socket and fire it up with a tube channel and the 5532 channel and compare the two. Take a bit of messing to set up to test it, but might be fun to see the results. And the reactions... If someone had gifted me one of those things, that's the treatment it would get. Make a decent headphone amp, the simplified way. (And chop out those LEDs!) Stu

"How can people possibly know this much about this 26 minutes long video 5 minutes after it being uploaded?" Because some of us are old farts who grew up using tubes.

William Beckham, I wonder if your old teacher was correct......as I understand the human ear, it is just a series of tiny hair cells that respond to excitation by different sound frequencies. If that is true, would they be able to distinguish between the different harmonics? One note's 5th harmonic can be the same as another note's 8th harmonic, and how is the ear supposed to react differently (and one is an odd harmonic while the other is an even harmonic). Seems to me that a lot of audio snubbery is really just folks misunderstanding, or improperly applying, physical truths.

+mikeissweet Good troll, but it has to be slightly more subtle.

+Spirit Lmao ding ding! Damn those audiophools.

+mikeissweet You almost had me until the magnetic field stuff. That is just a wee bit too far for even the nuttiest audiophiles I've happened across.

ugh, theres so much 'audiofool' bullshit 😉

Awesome... until the Earth's magnetic field, then it goes off the tracks. White laser? All fiber is "rigid", glass is glass. You redeemed yourself with the gold-plated brass however.

+mipmipmipmipmip Tubes, even crappy tubes, are more than capable of producing excellent quality audio. Even this one with a 1.6% specced distortion can most likely be coaxed into being plenty clean with a high enough voltage (which provides headroom) and relatively careful choice of biasing and impedance. The thing is though, transistors do all that stuff way better and easier and smaller and cheaper and less dangerously .. one of the only real uses I see for tubes these days is in guitar amplifiers, where the whole point is to slam the shit out of the tubes with insane gains and voltages, and really ride them past the edge of their standard characteristics. With all their analog goodness, the real fun comes when you mistreat them. The boring, linear region is not exciting and is better represented by transistors.

+TubiCal As MrCarlson said they would have been better off using space charge tubes. China needs to stop making random tubes and sticking them in stuff but building tubes designed to work on low voltage. Or they could simply use a tiny boost converter to generate the high voltage instead.

TubiCal The 1.6% figure is for a common-cathode topology with no NFB. Not a practical circuit.

If the signal level is low, there is no clipping due to bias.

When you're *producing* sound, you can use any method you want to achieve the sound you want, so using vacuum tube amps for recording purpose is fine. When you're *reproducing* sound, you should use whatever method produces the mathematically most-accurate amplification of the source signal, so you can be sure you're hearing exactly what the artist intended. That's why my home stereo uses a set of self-correcting JBL studio monitors with built-in digital amplifiers, rather than some ridiculous glow-in-the-dark vacuum tube setup, so I can hear my vacuum-tube-amplified rock albums with perfect clarity.

Supposedly 2nd order distortion 'harmonises' whilst 3rd order would be inharmonious, but I tried adding 2nd order using a plugin and it sounded dreadful.

the same with Tripath and some other amps, they ad distortion, but "good" distortion not the kind of distortion crappy Class B silicon amps ... there are of course good transistor amps, Class A, Class AB, even some good Class B amps ...

@@deusexaethera how do you know that the sound on the record is what the artist intended?

@@dcan911: Because they get to hear the master after the recording engineer is done with it, and request changes to the final mix. Or at least, _good_ musicians do that. I suppose Justin Bieber probably doesn't care.

The "warm" tube sound which, beyond physical laws and general logic, can only come from a real tube. Check out directional speaker cables too. And when buying them, make sure to buy the triple 24K gold plated contact 1999$ ones.

+drkastenbrot yea, but they are only worth to buy if they had been manufactored during moon transition!

"Audiophile" means "lover of sound", it doesn't mean "good at listening".

drkastenbrot Despite you can actually hear the coloration tubes give...

Retro Tech Teardown This is a cheap chinese snake oil unit and not comparable to authentic tube technology.

+Faisal Kadal except with guitarists. we have to feel and listen, audiophiles are just retards.

Logan Le Roux I don't know about guitarists, but I used to modifying and upgrading components in stompbox and guitar amplifiers, on request from my friends, I have many friends are bassist and guitarist, but I never know how to feel and listen to. But, yeah, audiophiles are ridiculous about how can they "feel", like they can "feel" the sound of cable touches the floor, because cable should not touching the floor, wow, just wow...

Come now, there is as much BS in the guitar community as there is the audiophile world. From "tone wood" to nitrocellulose lacquer. There are idiots who believe that the amount of beer spilled on their guitar adds all that "tone".

***** since i started seeing those headphone amps with tubes lately ive wondered if they really use the tube or if its just bs and now i know its basically just bs lol

+Michael Beeny I fully agree on that. I built a simple transistor amp with small voltage gain, but decent current gain. Even at same volumes on the output, sound with the amp in the circuit becomes a lil' bit better (better bass)

+Michael Beeny Good transformers won't cut much subbass or introduce any appreciable amount of phase distortion in audio band either. Some people actually even build transformer coupled amplifiers specifically because they're easyto make. The downside is mostly weight and output impedance - in audio applications.

+Michael Beeny LOL totally not true unless you use a garbage transformer. There should be very little distortion in a good transformer.

"Exactly why they didn't use the valve as an amplifier, not sure, . . . " Because that would take work and circuit complexity. There's no way they could meet their price point.

yeah well the price tag for that one is around 20 euros free shipping so.. with or without the tube it's more or less the same price

When you're *producing* sound, you can use any method you want to achieve the sound you want, so using vacuum tube amps for recording purpose is fine. When you're *reproducing* sound, you should use whatever method produces the mathematically most-accurate amplification of the source signal, so you can be sure you're hearing exactly what the artist intended. That's why my home stereo uses a set of self-correcting JBL studio monitors with built-in digital amplifiers, rather than some ridiculous glow-in-the-dark vacuum tube setup, so I can hear my vacuum-tube-amplified rock albums with perfect clarity.

That's a good sounding amp, a 12au7 can be used in 6 or 12 volt circuits. I had a push pull amp using a 12ax7, 2 6aq5's and one 5Y3 rectifier tube and it sounded good and loud for 10 watts.

Michael Moorrees The blue glow produces a "visible illusion" of power. If one were to see a high-power broadcast transmitter using vacuum tubes (e.g. the transmitter of any 50kW broadcast station before about 1980), a blue glow would be visible, along with the brighter orange glow of the filament, simply because so many electrons were flowing so fast with traces of other gases in the tube. Ironically, a blue glow in a receiving tube indicates that the tube is weak - that too much gas has accumulated in the tube.

honestly?... they have to do me a favour:: OR!! they start using white leds as indicators in devices with more that one indicator, OR!! i'll be happy with blue as well.... i don't see any major difference between the colors they use, i mean -greenred -redgreen -yellowgreenred -thatususalcolorusedtodrivedaltonicscrazy :D screw lan cards and arduinos!! i'm a proud daltonic!! :D but i agree

Because in 1990 blues cost £5 each, so to old engineers they still have an aura of luxury...

I'm old enough to remember when LED's were very small dots only on watches and calculators, and when the LM741 originally came out and sold for more than $10 each. Also 4 function calculators were over $200 and had a green display.

From the Peavey product page: *2x EL84 power tubes and 3x12AX7/ECC83 preamp tubes* Those are pretty standard types/quantities of tubes for a guitar head. Sounds like a normal tube amp design to me. EDIT: Electronics repair tech here... I've got a Marshall solid state head sitting down at the shop right now, really should get around to looking at that... :)

+TheEPROM9 Orange LED would be better.

Makes it look like gassy (air leak)

+TheEPROM9 Yeah, kind of sick of everything having blue LEDs. They look cheesy and crap.

Blue LED's have there place, but it is not in everything.

+TheEPROM9 The blue LED craze started in the late 1990s, almost every single bling bling black plastic crap electronic gadget were full of blue LEDs. Remember the color LED computer fans? yea... they had their day.

1% 2nd order harmonic distortion