• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

DIY? Where to start? Advice wanted

Hello all!

Just getting bit by the tube bug, and trying to figure out the best way to spend other people’s money on some Christmas present suggestions this year. Have no experience with Hifi let alone tubes, but want to put together a cool, interesting-to-me hifi setup for a small room.

I see highly respected designs all over the place (Tubelab’s SPP for example), but they do not feel modular/cheap enough for a beginner to open one box and start soldering with the intent to discover if they even like tube amps in the first place!

Does anyone have experience with these Douk/Nobsound kits? I recognize these may be sacrilege, etc. but I am tempted by the low price/high modularity while still getting to build it with my own hands.

For the same-ish money, the Tube Cube | 7 offers me a highly-reviewed and low risk opportunity to listen to a good quality tube amp but without the satisfaction of DIY.

Suggestions welcome!
 
Have no experience with Hifi let alone tubes...

If you have no experience of working with the dangerously high voltages found within a valve amplifier, I would advise you to go for the built option.

The TubeCube 7 has sufficient power for desktop use or for use in a small room with efficient (sensitive) speakers.

P.S. Note that the Douk Audio item to which you've linked is a preamp, and you would need to add a power amp to drive your loudspeakers.
 
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Does anyone have experience with these Douk/Nobsound kits? I recognize these may be sacrilege, etc. but I am tempted by the low price/high modularity while still getting to build it with my own hands.
The kits from China quite often lack any instructions, and the schematics often have errors.

Why not have a look at BottleHead kits, as they are complete and have full instructions and support.

jeff
 
Be aware that although widely available, the tube amplifiers do not meet safety standards.
Keep out of reach of children or pets or anybody that might come to harm.
Exposed hot glass tubes containing high voltage.

Sound wise a good tube amplifier will be no better than a more practical solid state amplifier.
Nostalgia for things that glow is the usual attraction - like a steam engine.

If you are comfortable that you can work safely around high voltages then go for it.
A PCB kit (as the Douk) will be easier to get right.
 
cheap enough
These days, "cheap" and "tubes" arent particularly congruent. China manufacture comes the closest to solving that dilemma, but as mentioned there could be hidden costs - like you put the whole thing together, it doesnt work right, then you have to ask for help in a forum, dig into until the schematic / wiring error is found - all the while poking around in or nearby those high voltages.

Not to say that'd be your experience, but I've read where others have had to go though it. Some think it's part of the fun, but perhaps not in time for Xmas!
 
I'm a total tube addict but I'm going to build a chip amp just as an easy experiment. You could start there - no high voltages to worry about. Loads of simple LM1875 kits on ebay and since the device is usually fake you also buy a genuine LM1875 to replace it. Lots of info on the chip amp forum. See how that goes and then come back to tubes. I'm looking forward to my build - they are supposed to sound really good.
 
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If you want to get into tubes I suggest having a look around for cheap output transformers. My first experiments started with some transformers I found on ePay for not much money. Edcor also has some budget options, including the CXSE-series.

If you want success from the start, I think Tubelab's boards would be a good way to get started. Note that he's closing up shop by the end of the year, so you might want to buy sooner rather than later.

As others have pointed out, tubes and cheap don't mix well. A "cheap" tube amp, such as a Spud design, will still set you back a few hundred bucks in parts unless you get lucky and find some iron on the cheap. By contrast, a cheap chip amp can usually squeeze in under $100 in parts. Both of these assume that you're content with a simple wooden chassis. It's easy to spend hundreds on the chassis alone.

Tom
 
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Hello all!

Have no experience with Hifi let alone tubes, but want to put together a cool, interesting-to-me hifi setup for a small room.

Suggestions welcome!
I suggest you buy a nice, working Dynaco SCA35, or similar, hook it up and start learning about tubes. Then modify it later with Dave Gilespie’s EFT power supply and boards. Enjoy, keep learning and next you know you are ready to DIY amp of your liking.

http://tronola.com/html/daves_store.html
 
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I keep thinking a useful entry level project would be a point-to-point wired, single tube stereo preamp with about 2x gain that runs on about 200V B+, with a 6.3V heater. I'm not sure anybody makes a kit like this, but it would be easy to design. Most of the work would be in making a chassis and collecting the necessary hardware (perf boards, standoffs, screws, punching the hole for the tube socket and drilling the holes for that and the other parts, the tube socket, suitable transformer(s), getting the tube, getting the resistors and capacitors, getting the RCA jacks, volume control pot and selector switch and installing them, etc.).

A single 6DJ8 or 6N8S configured as a common cathode stage (one triode per channel) with plate-grid NFB around it would have a reasonably low output impedance, high enough input impedance, and would perform well in most systems. It would add a glowing tube to your table.

The B+ supply could be made from a simple 117VAC:117VAC isolation transformer, with the secondary rectified by a full-wave voltage doubler.
The heater could be lit up by a simple little 12VCT 1A transformer.

Ah, maybe that's too complicated. Just a thought...
 
I second the Bottlehead recommendation: its forum is a friendly and very helpful resource for new builders. If you have high impedance headphones (300Ω or so) and can afford it, I'd suggest looking at the Crack. It's about as simple a circuit as you'll find.

But there are upfront costs in DIY: you'll need a decent soldering iron, solder, some basic tools. The cost of a kit won't include these necessary items.
 
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I remember my first valve pre amp build.
Found a circuit and built it up.
It didnt work so had a poke around and got a shock.
I had forgotten to discharge power supply capacitor.
So powered it up again and still didnt work.
I discharged the power supply cap.
Touched the circuit and got another shock, I had forgotten to turn it off.
That was in 1980, amazingly I am still alive in 2023 !
I found putting an LED and series resistor across power supply cap gives a good indicator of lethal voltage.

As someone else said hi fi valve systems dont sound too different from solid state.
The exception is guitar valve amps which are designed to produce lots of second harmonics to richen the sound.
 
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With all this negativity it's a wonder diyAudio exists!
Just go for it.
Many of the Douk designs are preamps or Valve preamps with chip amp output.
This would give the fun and effects of valves without too much excessive heat and high voltages.
They would also be simpler for a first project.
Take your pick.
 
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Take a look at the ZKit 1 Triode SET from Steve Deckert at Decware Only a couple of watts, basic 3 tube circuit, a 6922/6DJ8 and 2 EL 84's (lots to choose from) minimum part count, intended for 'educational' purposes, (Bare Board, No Chassis, you buy all the parts) but capable of reasonably Hi-Fidelity driving efficient speakers if built with quality parts. Was one of the first tube amp kits I built.