What might be a simple tube amp circuit that would best suite a beginner who's never built technology from scratch?
Would be nice if there's some documentation on it available that also treaches the builder on how and why everything works.
I have basic (and some more than basic but on some very specific things) knowledge about electricity, but not on circuit design besides filters.
Would be nice if there's some documentation on it available that also treaches the builder on how and why everything works.
I have basic (and some more than basic but on some very specific things) knowledge about electricity, but not on circuit design besides filters.
What speakers do you have? There's no point building something that won't give you enough power to enjoy your project!
Single-ended amplifiers are quite easy to build, and don't need to use expensive components. A single-ended ultralinear KT88 amplifier is relatively cheap to build and can get you 10-12 watts.
There are also some simple push-pull projects that can produce anywhere from 15 to 30 watts.
The most expensive part of of a tube project is the transformer set. Expect to spend several hundred dollars.
Here's an SE KT88 project that spells everything out for you:
https://m.youtube.com/playlist?list=PLo7DGF0CxJGnfxQSKWOXtvhF23jLjEpOC
Single-ended amplifiers are quite easy to build, and don't need to use expensive components. A single-ended ultralinear KT88 amplifier is relatively cheap to build and can get you 10-12 watts.
There are also some simple push-pull projects that can produce anywhere from 15 to 30 watts.
The most expensive part of of a tube project is the transformer set. Expect to spend several hundred dollars.
Here's an SE KT88 project that spells everything out for you:
https://m.youtube.com/playlist?list=PLo7DGF0CxJGnfxQSKWOXtvhF23jLjEpOC
RH84 immediately springs to mind. Tons of threads, here's one from 2009: https://www.diyaudio.com/community/threads/building-rh84-se-tube-amp.141434/
jeff
jeff
The alternative is to buy a ready made amplifier, maybe a cheaper older classic design, and upgrade it. A few of us started that way. You first learn safe practice with high voltages and once you have got that you can start analysing the circuit with a multimeter and writing out a circuit diagram with all the voltages.
Read something like Morgan Jones "Valve Amplifiers", even an older edition, or look at online tutorials. Your task is to understand how the whole amp works. Use Ohm's Law to calculate all the voltages, current and resistances including the wattages of the resistors. When you get that far you'll find it much easier to build a project yourself.
Read something like Morgan Jones "Valve Amplifiers", even an older edition, or look at online tutorials. Your task is to understand how the whole amp works. Use Ohm's Law to calculate all the voltages, current and resistances including the wattages of the resistors. When you get that far you'll find it much easier to build a project yourself.
Do yourself a favor. Start by acquiring or building a good set of speakers of relatively high sensitivity (90dB or greater). Don't sped a lot, just get something that has a decent sound. Good efficiency full range drivers in a horn enclosure or even a vented bass reflex cabinet can be nice. Just don't get carried away.
Then build a simple single ended design. Preferably something without feedback or exotic biasing schemes. This way you start with a simple topology and don't have to worry about phase splitters, balancing tubes, or instability conditions. These topologies tend to be simple and aren't prone to errors or requiring lots of fiddling to make things work well. You'll also get some build experience under your belt. Don't chase power levels or volume; just a couple of watts is more than appropriate for a first amplifier. The goal is a working amplifier with a nice sound. Once you have that built and running, see what you think.
If you think you want more power you can go to bigger tubes or a push pull topology, or both. If you like the sound you can try another amp with a different topology. If you want something not so "tubey" you can try a some global feedback. SETs, SE-UL, PP triodes, PP-UL, SE-Pentode, PP-Pentode, all with or without feedback, are all options. Good push-pull designs can provide more power than you'll ever need if that's your desire (but I would never start there). The point is, once you've gotten your feet wet, you'll be in a much better position to decide where you want to go from there.
And a word of caution. Along the way you're going to encounter lots of people with opinions (sometimes STRONG opinions), myself included. Do not let anyone tell you what you like or dislike. Do not believe them when they start extolling the virtues of one special topology or special exotic components. Some may feel the need to extol the virtues of silver foil, oxygen free, capacitors, hand rolled on the thighs of Japanese virgins under the light of the full moon, and individually blessed by audiophile mystics, but that's really just ego not engineering. Trust your ears. And remember "experts" are a dime a dozen. And none of the advice you get should drive you away from doing what you want to do.
I'm biased, so I'm going to point you to a couple of simple SE designs which are appropriate even for someone who's never picked up a soldering iron. But again, don't let anyone, including me, convince you to do something that you don't really want to do. Explore lots of designs but for your first build, simple is better.
Here are couple of examples:
The 6V6 Marblewood Amp
The 6CY7 V2.0 “Zebrawood” Amp
Above all, enjoy the journey. Ask lots of questions. And never stop learning.
Then build a simple single ended design. Preferably something without feedback or exotic biasing schemes. This way you start with a simple topology and don't have to worry about phase splitters, balancing tubes, or instability conditions. These topologies tend to be simple and aren't prone to errors or requiring lots of fiddling to make things work well. You'll also get some build experience under your belt. Don't chase power levels or volume; just a couple of watts is more than appropriate for a first amplifier. The goal is a working amplifier with a nice sound. Once you have that built and running, see what you think.
If you think you want more power you can go to bigger tubes or a push pull topology, or both. If you like the sound you can try another amp with a different topology. If you want something not so "tubey" you can try a some global feedback. SETs, SE-UL, PP triodes, PP-UL, SE-Pentode, PP-Pentode, all with or without feedback, are all options. Good push-pull designs can provide more power than you'll ever need if that's your desire (but I would never start there). The point is, once you've gotten your feet wet, you'll be in a much better position to decide where you want to go from there.
And a word of caution. Along the way you're going to encounter lots of people with opinions (sometimes STRONG opinions), myself included. Do not let anyone tell you what you like or dislike. Do not believe them when they start extolling the virtues of one special topology or special exotic components. Some may feel the need to extol the virtues of silver foil, oxygen free, capacitors, hand rolled on the thighs of Japanese virgins under the light of the full moon, and individually blessed by audiophile mystics, but that's really just ego not engineering. Trust your ears. And remember "experts" are a dime a dozen. And none of the advice you get should drive you away from doing what you want to do.
I'm biased, so I'm going to point you to a couple of simple SE designs which are appropriate even for someone who's never picked up a soldering iron. But again, don't let anyone, including me, convince you to do something that you don't really want to do. Explore lots of designs but for your first build, simple is better.
Here are couple of examples:
The 6V6 Marblewood Amp
The 6CY7 V2.0 “Zebrawood” Amp
Above all, enjoy the journey. Ask lots of questions. And never stop learning.
Some links to european parts suppliers that might be of interest:
https://www.tubetown.net/ttstore/en/ Tubes, transformers, chassis and pretty much everything else needed for (budget) projects. Germany
https://www.don-audio.com/ Pretty muck the same as above. Netherlands
https://shop.piemme-elektra.it/ Good budget transformers and chokes from Italy
https://www.lundahltransformers.com/audiophile/ Swedish transformer manufacturer. Perhaps a bit pricey for a first project
https://www.tme.eu/ Has some tube related transformers (Indel) and chokes (hammond) plus pretty much everything else. Poland.
https://www.tubetown.net/ttstore/en/ Tubes, transformers, chassis and pretty much everything else needed for (budget) projects. Germany
https://www.don-audio.com/ Pretty muck the same as above. Netherlands
https://shop.piemme-elektra.it/ Good budget transformers and chokes from Italy
https://www.lundahltransformers.com/audiophile/ Swedish transformer manufacturer. Perhaps a bit pricey for a first project
https://www.tme.eu/ Has some tube related transformers (Indel) and chokes (hammond) plus pretty much everything else. Poland.
I second the RH84 or other RH series amp. They are relatively simple but good sounding amps with lots of support from the many people that have built them. Parts are not exotic or expensive. They are close to fool proof as long as you have built anything electronic before. Remember, the voltages are very dangerous so be careful. The parts are inexpensive and easy to find online. Warning - tubes are a gateway drug! Once you build one it hard to stop.
I also recommend RH84. I'm no expert but after building 4 amps including a 300B I have to say the sound is very good indeed with my Dave designed Alpair 11.2 MAOPs (yes the ports haven't been bevelled yet). It is also very simple to build. I tried the first version and also rev.2 with zener and LM317. Not much different, perhaps a vaguely sweeter sound in the first version.
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Consider whether what you will build will be the very last tube amp you build.
It does not get simpler than a low power, 2 stage, single ended amplifier (2 Mono-Blocks, or Stereo).
Indirectly heated tubes, no DHT (Direct Heated Filaments, not cathodes) for your first amplifier, unless you are willing to use AC to power the filaments (DC filaments adds complexity).
There are only a few simple kits.
Point to Point wiring is a good thing, a little more effort to wire than using PCBs, but much easier to troubleshoot, repair, modify, etc.
I was not aware of the Decware ZKIT1 board.
The 6V6 Marblewood Amp
Can also easily be Triode Wired 6V6, lower power, but less distortion, and higher damping factor to deal with widely varying loudspeaker impedances across the 20Hz to 20kHz frequency range.
Remember, this will most certainly not be the last tube amplifier you build.
Have Fun!
It does not get simpler than a low power, 2 stage, single ended amplifier (2 Mono-Blocks, or Stereo).
Indirectly heated tubes, no DHT (Direct Heated Filaments, not cathodes) for your first amplifier, unless you are willing to use AC to power the filaments (DC filaments adds complexity).
There are only a few simple kits.
Point to Point wiring is a good thing, a little more effort to wire than using PCBs, but much easier to troubleshoot, repair, modify, etc.
I was not aware of the Decware ZKIT1 board.
The 6V6 Marblewood Amp
Can also easily be Triode Wired 6V6, lower power, but less distortion, and higher damping factor to deal with widely varying loudspeaker impedances across the 20Hz to 20kHz frequency range.
Remember, this will most certainly not be the last tube amplifier you build.
Have Fun!