Small homemade tube guitar amp with 6J1/6K4 pentodes (demo and schematic walkthrough)
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- Опубліковано 27 лип 2024
- This is a small desk-top tube hybrid guitar amplifier with two small chinese pentodes (running as triodes) as the preamp and a TDA2030 Hi-Fi chip as the power amp. All the voltage gain comes from the tubes and the solid state section drives the speaker - which is a generic 3 inch, 4 ohm "multimedia" speaker. The amplifier is built into a box for Darjeeling tea and it runs at a relatively low voltage (off a 24V DC adapter) and puts something between 5 and 10 watts through the speaker at max volume.
Edit: Though the tubes I bought were sold as 6j1 tubes, upon closer inspection they appear to be 6k4 tubes, which have the same pin layout but slightly different specifications.
00:00 Intro
00:29 Demo with camera audio
02:08 Talking about the circuit
19:48 DI recording
A few significant amendments/addenda (sorry!):
On actually measuring speaker voltage while playing, it turns out the output power is limited by the gain. With the guitar plugged straight into the amp it's really about 3 watts, tops (more if I put a boost in front). Still plenty loud for practice, though.
The tubes are 6k4's, not 6j1's. I got them as part of a preamp kit which was listed as using 6j1's, but was actually delivered with 6k4's.
The 6k4 filaments draw more current, so I increased the buck converter output voltage to a bit over 18 volts.
Turns out the 10M anode resistor on the second stage doesn't really give much extra gain after all. I tried a few different values and settled on 470k.
I've never learned so much about circuit design in such a short time before. Thank you!
Means a lot, thanks!
Love your little homemade guitar amp. I was surprised how well the unit sounded at higher volumes it had that wonderful warm tube Distortion just like a Vintage guitar amplifier. Nice Work ❤
Thanks! Glad you liked it :)
@@Psychotenuse You should do a loop rhythm through one amp & a lead guitar through this homemade one.
Finally found a channel explaining the circuits properly, good job mate .
Great content deserve more views.
Waiting for more videos
Yes, a great explanation.
What I know about electronics is minimal, but you present the schematic walkthrough in a way that is easy to follow and understand. Namaste
Glad you enjoyed it! Thanks for watching and commenting :)
Cool, that was like a short lecture. Excellent explanations. Thanks bro.
Glad you enjoyed it! Thanks for watching :)
Very well explained, all your videos are very educational, keep up the good work 👍
Thanks :)
damn bro you are so skilled with all of this !! amazing job !!
Thanks!
Excellent Video, Excellent Build... Thanks For Sharing..
Very cool!!
Great!!
Well explained
Thank you 🏴
Thanks for watching :)
just finished building one.Running on 50 volt with some adjustment to resistor values I found no need for a buffer stage. Sounds very nice
Awesome! You know, I actually have removed the buffer stage on mine since I made the video :P
in the Darlington Buffer, are each of the resistors connected to the tube output , or are they connected in series and the diagram just doesn't show the jump over tube output wire? That confused me when you crossed the lines in the schematic.
Also, is the audio input jack switch part of the DPDT from the guitar input jack? I noticed when you plugged the cable in the green LED lit.
Finally, great video. I liked how you drew the power rail and showed how the other components attached to it. Made it very easy to follow.
That's connected, it's a voltage divider for biasing. Doesn't actually need to be there tbh, you could DC couple that part and it shouldn't make too much of a difference.
Nice project man...I thought to build a tube amp using 6j1 you made my job easy I am planning to make around 50 watt..
Glad you like it!
50 watts is a lot... I assume you're going to be using a class D power amp then?
@@Psychotenuse yes you got That right man..👌
@@adventsmusic8997 you should post when its finished !
please make steps by steps soldering, wiring and stuff, that would be awesome👍
You see, that sort of thing is feasible for simpler builds, but for something with, say, fifty or a hundred solder joints, showing each one would take a lot of effort and would make for a boring video...
Great job. This is such a cool design. Have you checked the max voltage output the 2nd tube and how much input swing the power amp chip can take without clipping? I was thinking about hybrid guitar amps and how to ensure that only the tube stages get overdriven while the solid state output stage has lots of headroom.. so all the distortion is from the tubes!
The power amp section here has no voltage gain, so there are no headroom issues as such. If you want to overdrive the tubes though there's just not enough gain so you'll need more stages.
Kya baat hai
Beautiful build and explanation.
One question: is the gain potentiometer linear or log? The volume should be log though.
Thanks
Thanks :)
Since the maximum gain is pretty low, I think linear probably makes more sense.
Exceptional... I've never had much luck with amplifiers but never tried to make a tube amp. Btw I started my new youtube channel and posted a video of my synthesizer. the channel is Hackmaster and the profile pic is a plasma globe.
Nice, I'll check it out :)
Hey, I was looking to build a fender replica with a 12AT7 and a 12BH7A but would love to start with this one as it's cheaper. Could you put in a parts list I can use to order online? Some links would be very helpful. Btw, where in India are you?
Cheers on the build. Sounds awesome!
Glad you like how it sounds! I didn't really have a way to record it "properly", unfortunately.
You might want to take a look at the UA-cam channel Kris Slyka. He's the one I got the inspiration for this project from.
Anyway to be honest, the reason I didn't include a parts list for this project is because I've actually constantly been making tweaks to it and I'm not sure I even remember all of them or what parts I used at this point. The general principle is the same, though... two stages of pentodes running as triodes, then an op-amp buffer.
I got the tubes as part of a kit which you should be able to find if you search for "fever 6J1". It seems like the cheapest way to get tubes in India, unless you order internationally from Ebay or something. The kit also has tube holders, a power jack and some capacitors you can use.
Can you make acoustic guitar amplifier with lm386 ic? 🥺 🥺 🥺 🥺 🥺 🥺 🥺 🥺 🥺
buscando proyectos pequeños me encontré con este genial como para tocar en el dormitorio sin molestar a los vecinos... me gustaría poder hacerlo pero cuando aprenda ingles podre entender bien la explicacion...me gustaría saber master donde puedo ver el diseño de este pequeño amplificador me gusto como suena..se agradecería información
Lo siguiente es de Google Translate:
Muchas gracias por tu apreciación. Honestamente, no tengo ningún buen documento de diseño que pueda darte. Hay dos razones. Primero, el circuito en este video no era 'adecuado' porque estaba equivocado sobre qué tubo tenía (tenía 6k4 pero pensé que eran 6J1). Por esta razón, los valores de la resistencia y el voltaje de suministro del calentador estaban por debajo del nivel óptimo. La otra razón es que durante los muchos meses que he estado usando este amplificador, le he hecho muchos ajustes. En este momento ya ni siquiera estoy seguro de cuál es el circuito exacto xD
De todos modos, ¡muchas gracias por mirar!
Is there any hiss from the 6j1?
Hard to say exactly where any hiss would be 'coming from' exactly, since 'coming from' is not really that well defined here
This is amazing! Just wanted to check if this can be built using 1j24b tubes, I think they can run at 1.2v of heater voltage. Could these be a direct drop in for 6j1s?
The amp sounds wicked! Cheers
Glad you like it! The tube you mention certainly doesn't look to be a "drop in" replacement, unfortunately.
Actually, the tubes I used turned out to be 6k4 tubes, which clearly are drop in replacements (sort of).
Oh shucks ok!! I had ordered some 12 of these 😂 used just one in a eurorack VCA, thought of making an amplifier using these. Let me fiddle around with your circuit using these 1J24Bs (considering both are low voltage pentodes albeit different) and see if I can cook up a workable circuit or end up breathing in some magic smoke from an experiment gone wrong 😅 (these tubes are super flimsy and a pain in the rear end to breadboard with!!)
Hey finally got around to making this with 1j24bs and got some sound!!!! Not as clean but sounds OK...used an lm386 for the power section....waiting on an 8 inch guitar speaker.....tried using a tda2030 for the power section but it gets super hot in like 5 seconds or so....any idea why the chip is getting so hot (have a heatsink for the chip...feels pointless)...currently using a tiny speaker that's rated at 1 watt!
It's class AB so it's expected to get a bit hot... but then that's also true for the LM386. I don't know why one would get hot and not the other. If you have a heat sink, you should use it. The TDA chips have built-in thermal protection so you might just get louder output with the heat sink.
@@Psychotenuse yup using a heat sink with the tda2030 but it still gets super hot incredibly quickly and I chicken out and turn it off fearing the ic will burn and/or explode….Have given my folks enough to be scared of with exploding capacitors already 😅….had two tda2030s around and both got incredibly hot…have heard fake ics get very hot..not sure though if the ics I have are fake or not …will stick to an lm386 for now
I would of connected the dc to dc direct to input pwr and put darlington current delay on dc to dc output and connected filaments in parallel...use a FET to buffer tube to amp and use a small class D amp board(TPA3116 or 8) for the amp...
Yeah, good ideas. I can get away with not doing things this way because it's a low power amplifier. Not sure that an FET buffer would be categorically better, though.
@@Psychotenuse Ya it overloads nicely, got the idea from an old VOX amp circuit...and has a high Z input and low Z output, what you want there...