The plastic box adds a lovely "factory look" to the amplifier. Thanks, really nice video. Greetings from sunny Jamaica.

I made my first tube amplifier after watching this video. Worked perfectly and sounded very good, for a while. Then the HV boost converter failed. Put in another converter and it failed after a few hours. Tried various Chinese boost converters from Aliexpress and other sources. They lasted from minutes to a few weeks. Then they all gave up the ghost. Got a standard linear power transformer replacing the last failed boost converter, amp has been working perfectly for years. Have since made 12 tube amplifiers, all using standard power transformers. None have failed. If people have used a boost converter and it has lasted, then I'm happy for them. And a little envious. I know a linear transformer costs more, but in my limited experience it's worth it. If you have made this amp with a boost converter and it's still working, let me know here!

Single ended tube rocks, back to the basics. 👍 The vintage solid state amp is a gem too.

Tube Amps are so much warmer and sweeter to listen to...Nice Job

I built an amp identical to this except I built a full dc/dc inverter to give me a 230v supply. Can't beat the sound. Love it, the imaging is stunning. Never heard sound this good.

That extra stereo imaging "thing" a decent tube amp and GOOD speakers provide is called "sound-stage", the wow that comes from being able to identify the exact location of each instrument. This design is a great practical new build approach. I love the elimination of the power transformer, when there are so many power bricks laying around everywhere. (I wish I hadn't thrown out all those old, dead big-iron receivers and amps years ago - they had gigantic PT!)

This is a marvellously clear demonstration video! Very interesting even though I may never build one myself.

Great work! The kit companies will not be happy with this video, but us hobbyists are! Thank you.

what an excellent video,thank you. and be assured the sound quality and clarity is not an illusion.i recently built one of those single ended valve kits from china and made a few upgrades (,better valves,connectors,and a diode full bridge rectifier). and got similar pleasing results. thanks again and happy hi-fi

Nice project and well documented. I can tell you have a technical background in electronics. I know tubes sound good for guitar amps. I would like to build a minimalistic stereo amp like this one.

The PCL82 was a common audio output valve used in UK TV's during the 60/70's, the ECL82 with 6.3v htr was used in many a record player of the time.

Man! THANKS! You rock! Super detailed and useful video, hope the YT community learn with you how to do a DIY project

Nice and detailed construction :)

@rodnezstipha4496

7 жыл бұрын

ABC

One recommendation for beginners that want to replicate this design; add a front-panel-mount neon indicator, and wire it across the B+ supply; not only does this act as an on/off indicator, it'll tell you if dangerous HV is still present; once the indicator goes out, then there's only about 60 volts or so (the breakdown voltage of a neon bulb) left in the capacitors in the boost converter. A 220 kilohm resistor in parallel will also help drain away the charge. :)

@Juicexlx

6 жыл бұрын

Yes, a light indicator is a good idea if only because it looks cool in the dark. Lol! He used a power block from an old pc to lower & regulate his voltage. IMO, his amp doesn't need a resistance to bleed the capacitors, but that could be verified with a multi-meter & a chronometer as an experiment of bleed time.

@rubenproost2552

3 жыл бұрын

Also they dont come in overly bright blue.

I like old school analog audio VT designs even if an entirely different generation from digital signal processing, high bit rates AD/Cs and DACs it gives you a lot of skill with your hands and listening. I will certainly build one myself very soon. Of course everything will have some crossover hybrids between the old and the new somehow.Thank you Electrolack its inspiring to see the renaissance of the Tubes these days. Reminds me of old professor's textbook of Frederick Emmons Terman - Radio Engineering.

Nice build ..... I built a single ended valve amp (for guitar) from scratch last year which was fun and I am pleased with the tone quality. The parts for mine were a lot more than £100, although I did use a PT + a valve rectifier circuit and also had to buy a speaker.

@electrolark9841

6 жыл бұрын

I think that's a good choice for a guitar amp because they are usually driven hard into limit which inevitably brings the rectifier into the picture.

Great, awesome build, I’d love to see some more of your videos. Shame this is the only one on your channel 😊

A really nice build. Kudos! It had to be a very enjoyable process and most satisfying result. I really enjoyed watching your video.

Great video...thanks for posting!

Great I've been looking for something like this to build. My Klipsch Forte speakers don't need much power.

This was a wonderful video to watch, well spoken, intriguing to follow too.

@electrolark9841

7 жыл бұрын

Thank you.

@enigma7070

6 жыл бұрын

I second Dave K's sentiment!

@robertbarker2458

6 жыл бұрын

Electrolark the valve amp does sound awesome

Excellent work. Well done!

A great video! I suspect many will follow your example. I think I can hear the difference - the valve amp sounds sweeter. I wonder if that's a shortcoming of that particular transistor amplifier? Only the better solid-state amplifiers are normally referred to as sweet-sounding...

Thanks for this. Only because I watched a video this morning, the LM317 is a good VR, but using a buck converter is much safer. If, for some reason, the 317 gets too much voltage, it will get hot and possibly exceed it's threshold of 125 degrees C (app. 250 degrees F), though this is a high value. Once this happens, it will shut down, then come back on when it cools enough. Just food for thought. Great job.

Great build! Thanks!

Beautifully done!

I built my own tube amplifier using an ECC83 and a couple of Russian 6L6 clones, it sounds great but since I dont have the proper output transformers I just had to settle for using a couple of mains step down transformers instead so it doesn't output anywhere near the amount of power it could do mainly as the impedance is way out (especially if I use 8 ohm speakers) but it still works well. If I ever find any proper output transformers, I'll then go though the process of setting the bias correctly along with the plate voltage and current.

Excellent build, big thumbs up! If I may suggest, using 11BM8 (LCL82) tubes with their heaters wired in series would simplify the project even more because each tube heater requires 10.7 volts and 2 of them would equate to the voltage output of the computer power supply, therefore eliminating the heater voltage regulator. Also, because these xCL tubes love to self oscillate, the addition of grid stopper resistors in line to each grid of the tubes very close to the socket pins (1k at pin 3, 22k at pin1 and possibly 50ohm at pin 7) would help if this phenomenon occurs.

This is lovely. I am planning my first valve build and this really helps thanks.

Nice job man. Nice to see those high voltage modules in a working environment. Jack Ma would be proud!

Excellent video, many thanks. I recognise the PCL series of valves as the ones traditionally used in TVs. They have unusual heater voltages, so have been unpopular for hobbyists. Now with the availability of cheap DC power supplies from China this is no longer an issue. So when I searched Ebay I was expecting the find the PCL82 going for 50p or a quid. Much to my surprise even these valves have asking prices of £5 - £10. Anyway I have a small stash of valves so I will see if I have any ECL82s and I will have a go at building a mono channel. BTW I recognise the schematic (the style is quite obvious) from a magazine called Radio and Electronics Constructor. Also thanks for making me aware of the HV switch mode PSU. £4 - what a bargain!

@electrolark9841

6 жыл бұрын

Thanks for the comment. You might like this archive if you haven't already found it- www.americanradiohistory.com/Radio_Constructor_Magazine.htm They have several other British magazines such as PW and WW.

Nice thing to add would be a grounded sheet of metal bent inside the chassiss as a housing for the power supply parts, so it covers the power supply from other componnents, power supplies tend to generate a lot of noise that you can hear and see on oscilloscope if the amplifier is inconveniently grounded. Wich is hard to tell before you get to test

Tube sounds better from high end of low pass all the way thru the audible limit. In comparison, the other two attenuate same frequencies, the transistor the better. I like how you approached the project; especially starting up. Thanks.

Thanks so much for sharing this, the video, the clear schematic and the slow-start circuit, which is pleasure to watch. I used a BC557 as the pnp transistor- I see that the value of the 240 ohm transistor needs to be quite precise to get to the 15 volts. I do find that the sound is lacking treble on low volume settings. Great instructions - thanks again.

"A lot of what is considered knowledge might just be in people's heads" Classic. No knowledge in my head I can assure you. I thought the tube amp had a pleasing distortion to it. I'm sold - I hope to find time to build my own version.

Hmm nice idea to use a buck-boost converter for the HT. I was thinking of making a guitar practice amplifier using valves, but decided not to when I looked at the price of a suitable 200 - 0 - 200, 0 - 6.3 volt mains transformer !

Fun project. One thing you may not be aware of, your original design to have the left and right output transformers placed at 90° to each other was ideal as it would have reduced the magnetic coupling between them. It appears you changed their orientation to fit the strip between them. Better probably would have been to cut the strip in 2 and orient up-down back-to-back on an L bracket inside the plastic box so you could accommodate the transformers at 90°. If you end up redoing any of it, something to consider as a small improvement. I suspect you didn't include bleed resistors on your series capacitors for simplicity and if they blow up, get the single required size. Thanks for sharing your build. It looks great !

@lannydavidson139

5 жыл бұрын

Good idea, I always mount my output transformers at opposite ends of the chassis,never close together to minimise coupling between them.

Hi, looks like a great amp! Quick question, if I were to use the transformer and diode rectifier instead of the power brick, what kind of transformer would be right to use for US grid? Thanks!

I can hear its much clearer through the tubes. Love the old systems, made almost from raw elements. I think we have to face it - do we like the sound of electricity passed through rocks or a vacuum. I wonder if there is a third medium as yet untried. Tubes of the future?

Really nice work!

I love tube audio, it's warmer

@charleszhao9936

3 жыл бұрын

not too distorted? with this level, the distortion may be too high for my taste

May I know , what speaker you use to play that music for amp test?? :)

great video. what is the exact name of the thing like strip. the part you solder components to it? thanks

Very neat work and layout.. If I lived near your area I’d pay you handsomely for some valve preamp/amp projects I have in mind.

Nice built !

I would love if you put in the parts list and the schematic maybe on the next build great video

Nifty amp, I'm in the process of building a stereo amp but with some 6SN7 and 6V6 tubes from parts sourced from a old Radio and a few Oscilloscopes. At first I was going to just build a preamp and use solid state for the main power amp but after looking at my inventory stock I'll just build it all tubes. I just need to order two matched output transformers.

Excellent video on your build. Interesting using buck regulator for the 220v section . Think that type valve was sound in TVs , Thankyou for posting. I would love a valve amp again might copy your ideas , deffo easier to source the parts you used rather than trying to find an old mains transformer

Great video! Thank you very much.

There's a documented phenomenon of even order harmonics existing in abundance inside a vacuum tube. These are the natural harmonics that are most pleasing to the ears. This is the main reason tube amplifiers feel warmer n sound more natural

Great video and build. At first I was all set to get all upset by the absence of a PT. But the boost converter seems to run well! What current do both channels draw including heaters? And what's the output. Do you need really high efficient drivers? I really love this build. Well done!

@electrolark9841

7 жыл бұрын

I understand what your say about the transformer and had this been a guitar amp then I would have been a lot more concerned myself but as it was for "HiFi" and nothing was been pushed I thought the converter was worth trying. The total draw is 1.7A at 20.5V the heaters are 0.6A for both and each channel is biased at 35ma. I think the speakers are 88dBm so not particularly efficient. Many thanks for taking the time to watch the video and comment - I'll really appreciate that.

@Ratgon

7 жыл бұрын

Electrolark ha! I can't stop watching the video! I'm very new to all of this having just started down the road of learning any of this a year or so ago. Approaching the design this way seems brilliant to me. I suspect it's not the first time anyone's done this but it still kind of blows my mind in it's bucking convention. Not only that but having watched simply 100's and 100's of hours of tube amp building/theory videos I can say that the video itself and the illustration of the actual build is incredibly unique. No one goes into this much detail. It's as if there's an unspoken agreement to hide certain steps from beginners. Hell, I've already ordered three of the converters from EBay.

Um ótimo trabalho, inspira tentar confeccionar um igual, de tão bem detalhado . Um amplificador assim ligado a caixas de alta sensibilidade é um deleite , ainda mais com mídias analógicas Parabéns e saudações do Brasil

I am really impressed.

well done sound much better than the transistor amp The PSU design great idea those valves were mainly just used in black and white tv's from 1960's and still produce great sound.I recommend William's mods

@electrolark9841

6 жыл бұрын

William's mods? you mean a lamp and bleed network?

Great video, am collecting the parts to build one myself. Just wondering what value of potentiometer did you use for the volume control? Thanks

What are the specifications of those transformers? and are they good for 8ohm speakers? also, what is their power rating?

really good video, to the point. thanks

Enjoyed the video. You should make more.

I was wondering how can i get the schematic for this amplifier?

Excellent Mr!

Hello ElectroLark )) I havecbuilt a amplifier preamp combo. The preamp is with 6j1 tubes. The are the smaller ones. Have you tried using various tubes on your amp? Will I get a better sound if I replace the 6J1 with these 16A8 tubes? Are all tube sockets similar?

Just wondering if there should be a chassis protective earth when using a double insulated stepped down supply but then bumping the volts back up again inside the enclosure? If not for shock protection, perhaps for EMI?

@msmith2961

6 жыл бұрын

Great video and build by the way.

I got excited when I saw my class a technics amplifier and I must say, sounded good! Thanks for the tutorial!

@russellhamner4898

4 жыл бұрын

I think I had that same Technics receiver or one very similar back in the day. Early 80s (a/k/a GREATies) vintage. Not great, not terrible. Think it cost me $20 at a garage sale, and I picked up some Infinity bookshelf speakers with it as I recall for a few bucks more.

Loving Your approach, and I've just bought pretty much the same components for My project. Aww Maplins, what a shame they've gone. Anyway Best Wishes Dee : - )

If you didn't know this, many variable voltage regulators can actually be used as an audio amplifier, simply by passing the audio signal to the adjust pin(plus as positive or negative bias you need to add to pull the voltage into the appropriate range).

nice work mate

Interested to know how you printed the plastic in an ink jet. It could be a useful thing that.

Hi.. Kindly help me with the output transformer details.

Awesome video!

This is a great build and a wonderful explanation and video! It was a pleasure to watch. It encourages me to try something similar.

woah woah woah wtf. Picture at 1:45, Hayling Island bridge in winter taken from either the Royal Oak or Ship Inn. Really didn't expect to see my hometown in this random video!

Your video shows 560 k&R resistors when the circuit shows 470 and the 330K (R4) ?

Brilliant video - what is the spec of the o'/p transformers - Thx

The Technics isn't a true Class A amplifier. It's what was called a non-switching circuit. They achieve this by putting the output transistors in what's called a linear state (not hard on). In a true Class A amplifier the transistors are switched hard on and generate lots of heat and draw lot's of current very inefficient but are said to be very high sound quality. The Technics system give you all the benefits of class A/B with just some of the benefits of Class A. Great video love to see people build equipment. My opinion is they do sound much better and warmer than transistors. I still have the two power amps and preamp my late father built in the late 50's. He rebuilt them and did some modifications on them when I showed an interest in the 1990's. They are still working perfectly today.

Nice, what value is the volume pot ?

Good morning friend! I congratulate you on this project! is it possible can you share the diagram? I'd like to do it! since I have the valves PCL82!

Great video,anyone got a link to a budget kit worth building from Ebay ? tia

I can’t believe this is your only video ! Please consider doing more this is the 1st tube build that seemed I could actually take on as a newbie.

I loved the video - I've been looking for a easy to build valve amplifier to get me started and I thing that this amp is the one! One Question @Electrolark : what output transformer did you use ? I cant tell the specs from the schematic.

@Nirky

4 жыл бұрын

Unbranded single-ended 4.2k primary/4 ohm secondary. Anything with a 4-6k primary should be fine.

Really brilliant video, thank you so much. I was inspired to build my own after watching it. The amplifier worked first time, which I consider to be a minor miracle. Could I ask a question please. Although the mids and highs were clear and sweet, the bass and low mid was really thin, and not warm and full, as described by others in the comments below. So I must have done something wrong!!! Do you have any suggestions to try and improve this. Thank you again

@marcusracky3121

Жыл бұрын

Hi, i am just guessing here but to me the input decoupling caps w 10nF seem way too low. Am i wrong?

@andrewsmith1874

Жыл бұрын

@@marcusracky3121 Yes people had said that to me. We tried more common sizes..... but to no avail. Also tried a larger output transformer, but it was not discernbly different. I am now running it through a pair of KEF Concordes, and it is pretty good. Maybe my expectations were too great. eg, Madman Across The Water by Elton John sounds huge, and luxurious, with lots of bass. So maybe it is just me, or just some songs that do not do it. It would be great to hear from other people who have built this amp. I really like the amp anyway.

Any idea what the output power is? Just interested. Really enjoyed the video. I might have a go at this myself!

@electrolark9841

7 жыл бұрын

About 3 watts per channel.

A nice idea to simply use a power brick, and some regulation circuitry. Surprised you only needed 2 amps though. Must only be using 20 V rails or so, and 8 ohm speakers.

I image ECC83 and EL84 would adapt. I like the boost converter. R4 I guess is shunt feedback. ECC81 might work as higher Rp. R6/5 unusual as no bypass. The latter might give it better than average sound.

it is advised to use linear power supply's whit analog amplifiers, but I was surprised how not noisy the audio was!

I don't know what it is with the tube sound... But on a cheap 10w output amp, I could clearly distinguish guitar mistuning in Rammsteins music 😲 I have a blaupunkt Arkansas 58 at home. Mono only and not much power, but the quality is incredible. Never restored anything, only removed webs and dust inside a bit. The whole case is part of the speakers resonator. Also the speakers are high reluctant. Mono only, I need a second Arkansas! 😍

I think this is a wonderful project, and guess what? Going to give it a go....I often pondered about power supplies and this seems to have an answer to the vexing problem of huge PSU supply transformers....I listened to the track by 126ers on youtube and through halfway decent speakers and then your the demo....by comparison between the solid state and tube and even after consideration of Mic placement noticed far more depth in the tube amp.! Very nice job...Ian

@electrolark9841

6 жыл бұрын

Good luck if you do give it a go.

where did you get your output transformers from?

Excellent!

I would like to build this but I'm at a loss....I can't find an output transformer

Hi I have a question about the value of R4--the anode to anode feedback. The first schematic you showed, its value was 3.3 Mohms. On your final schematic it's listed value is 330k. Is this a typo? And if not, why did you change that value? Thanks!

I dramatically prefer the sound of a tube amplifier, particularly in the vividness of the midrange and depth of stereo image. I have solid state gear as well; its good and plays clean, but it just sounds "hi-fi" and not "lifelike".

Since it's a class A amp, the plate voltage should be biased to half the supply voltage. Both sides should be the same. Did you check?

@Nirky

4 жыл бұрын

Datasheets shows PCL82 170v plate max.

a wonderful video

Of course anything analog is going to sound better than digital. Every musician knows this. Cathode tubes rock! The best rigs are point to point wiring. Sending your sound signal through some tiny wafer of copper on a printed circuit board kills the reproduction at the speaker end. Take apart an old Marshall plexi and you will see, and they used el34 pentode tubes which are meh on a good day but powerful. 6L6's or 6550's really sound good. Interesting vid. Thank you.

The tubes attenuate the "ringing highs"?

Hi, can you post the eBay links you get the parts from?

Just looking at your circuit description, where you say the triode is getting 'positive'feedback from the resistor divider in the pentode cathode circuit. This is negative feedback for both the triode and pentode. The signal on the triode anode is out of phase(with input), therefore in phase on pentode anode and reversed again on cathode so pentode cathode out and triode in phase - you generally never want any positive feedback in an amplifier, as it can make it an oscillator. Very unusual circuit though and you normally never see that 'bootstap' style R4, in simple valve designs which is maybe where the positive thought came in? (Bootstrapping was a small amount of positive feedback to improve impedance matching, usually over two stages (of similar type) so it was positive). I may be wrong, I often am, but I can't see any positive feedback at a quick glance. British valve (Mullard Philips) nomenclature had the first letter give the heater voltage/current, 'P' 300mA. Second internal construction of valve 'C' for triode and next same 'L' for pentode (and so on for valves stuffed with bits, EABC80) and then the specific number in a range of valve base identifiers 82 - B9A for this example. 30s for international octal - You can look up the system.

@martinda7446

6 жыл бұрын

PS I note the original design had a 3.3 M (dropping to 330K is pushing it somewhat)) But.. it seems to work OK and has enough gain.

Try triode connection on the output tubes, just tie screen grid to the anode (some use 100 ohm resistor). You will drop distortion to a much lower level and power will drop to under 2W...But you don't notice, it sounds subjectively more powerful - and twice as amazing - to us nutters? Anyhow its so easy to do it's worth a try.

@finneganzahir6598

2 жыл бұрын

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@maximussamir2332

2 жыл бұрын

@Finnegan Zahir Instablaster =)

@finneganzahir6598

2 жыл бұрын

@Maximus Samir thanks so much for your reply. I got to the site through google and I'm waiting for the hacking stuff now. Looks like it's gonna take a while so I will reply here later when my account password hopefully is recovered.

@finneganzahir6598

2 жыл бұрын

@Maximus Samir it did the trick and I actually got access to my account again. Im so happy! Thank you so much, you saved my ass !

@maximussamir2332

2 жыл бұрын

@Finnegan Zahir Happy to help :D

Great video, Electrolark. Question for you: How's the low-end on this amp? Most of the tube amps I've listened to (the hifi ones at least vs the guitar amp variant that I usually build) are quite lacking in the low-end.

@electrolark9841

6 жыл бұрын

Thanks, the trouble is, hifi needs big expensive transformers to get anything like good low end without distortion. The compensation with this amplifier is spatial performance, it seems to offer something special in that regard. I think that might be down to the lack of overall voltage feedback, that means the amplifier responds to the speaker impedance in a very different way. Guitar amps are a different story, the art seems to be getting the right type of distortion, for that reason I'm not sure I'd recommend the solid state power supply approach, but then I'm no expert.

@geraldhinson

6 жыл бұрын

Electrolark I agree on the spatial aspect. It's very easy to hear that difference in my headphones. I don't mind augmenting the design with bigger transformers. I would probably do that anyway. I might also pair it with a tube preamp with tone controls to help beef up the bass a bit too (yeah, I know... i'm not a true audiophile... ;)). Have you done similar? Fun stuff. Thanks for the reply.

@geraldhinson

6 жыл бұрын

Btw, if you still have it I'd love to hear an example of some rock music through it. Zepp, ac/dc, eagles, floyd?

Thanks for this! The quality of sound from any amplifier is purely subjective. Measurements (frequency response, IM distortion, harmonic distortion, and damping factor) can prove which amp more accurately drives a *specific speaker* to reproduce a given input signal. That isn't subjective. I find that tube amplifiers often correct (or hide) terrible recording quality. I suspect most recording engineers went deaf 10 years ago, and most of them produce pure crap. I find that pro speakers (big JBLs, EVs, Wharfdale, older Klipsch, etc) provide the most consistent grins from listeners, but Wife Acceptance Factor of such systems is inversely proportional to sound quality. Carmina Burana is a good test. Tracy Chapman's first album is well recorded. The Voice Squad is a good test.