Hi folks
I'm competent with a soldering iron but have never built an amp before. I noticed on ebay that there are a plethora of DIY kits available from China, a mind-boggling array in fact. I had in mind to build either a valve amplifier with valves in both the pre and power stages or perhaps a hybrid with a valve pre and solid state power stage.
How good/bad are these kits? Are they competent, solid designs so that if I replaced some components with higher quality ones, it could sound pretty good?
I just thought that it would be a fun project to build an amp using cheap Chinese kits and then slowly try to enhance it by replacing parts, beginning with better valves, then better capacitors etc.
I'm competent with a soldering iron but have never built an amp before. I noticed on ebay that there are a plethora of DIY kits available from China, a mind-boggling array in fact. I had in mind to build either a valve amplifier with valves in both the pre and power stages or perhaps a hybrid with a valve pre and solid state power stage.
How good/bad are these kits? Are they competent, solid designs so that if I replaced some components with higher quality ones, it could sound pretty good?
I just thought that it would be a fun project to build an amp using cheap Chinese kits and then slowly try to enhance it by replacing parts, beginning with better valves, then better capacitors etc.
Not a real kit but still... A few audio friends were tricked with a nice case containing 2 pieces Sanwu TPA3118 modules combined with a linear DIY PSU with Rcore transformer. The modules cost 6 US $ a piece.
Some gave this amp a very high note. This note was often adjusted after they learnt what was inside the case
Kits often contain dubious parts and mediocre transformers so often there is a need to upgrade before you even start the project. IMO it us more effective to gather good modules and combine those. A positive exception regarding tube amps is Elekit from Japan but they’re not cheap.
Some gave this amp a very high note. This note was often adjusted after they learnt what was inside the case
Kits often contain dubious parts and mediocre transformers so often there is a need to upgrade before you even start the project. IMO it us more effective to gather good modules and combine those. A positive exception regarding tube amps is Elekit from Japan but they’re not cheap.
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If you don't mind buying a chassis, and building a power supply, go to
QKits Electronics QKits Electronics Store Kingston Ontario Canada.
There are a number of quite good quality amp kits there.
QKits Electronics QKits Electronics Store Kingston Ontario Canada.
There are a number of quite good quality amp kits there.
This board looked interesting: Assembled 12AX7/12AU7 tube pream board Pre-amplifier Board AMP Classic circuit | eBay
I figured, stick some good quality tubes in it and it might sound okay, or maybe replacing the 8 caps with better ones would make it perform quite well?
Can anyone recommend a good, budget kit for a beginner? A valve/tube pre-amp to begin with, I can add other bits like a power stage later.
I figured, stick some good quality tubes in it and it might sound okay, or maybe replacing the 8 caps with better ones would make it perform quite well?
Can anyone recommend a good, budget kit for a beginner? A valve/tube pre-amp to begin with, I can add other bits like a power stage later.
There is no transformer in this kit. It also appears that the valves/tubes are not included.
In the right circuit, the 12ax7 is an exceptionally good performer.
I find the inexpensive china made 12ax7's (with the thick glass) to be decent value.
I would consider these:
EL34 Valve Tube Amplifier Single-ended ClassA HiFi Stereo Amp DIY Kit Audiophile 9616865696381 | eBay
2017 Douk Audio HiFi Valve EL34 Class A Single-ended Tube Amplifier DIY Kit 1Set 7921734953307 | eBay
Both have sufficient space for possible modifications. Some 5...6 Watts is realistic, not 12 W as advertised.
EL34 Valve Tube Amplifier Single-ended ClassA HiFi Stereo Amp DIY Kit Audiophile 9616865696381 | eBay
2017 Douk Audio HiFi Valve EL34 Class A Single-ended Tube Amplifier DIY Kit 1Set 7921734953307 | eBay
Both have sufficient space for possible modifications. Some 5...6 Watts is realistic, not 12 W as advertised.
IMHO and two cents worth:
#1 The good, they are not that expensive and any mistakes make are not too pocket book painful. The bad, you do get what you paid for.
#2 I agree with the two good suggestion in Post #12. The 2nd one with point to point wiring can be easy to make changes and modifications. The good, these are basic and solid single ended Cathode bias design. They can sound pretty good with the right amount of NFB. The bad, it is somewhat basic.
#3 The fun part I agree, both building and modifying it. Just don't over do it with expensive parts.
Also don't expect much instructions from these kits.
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IMO some of the best tube amp kit values are made in Japan by Elekit.The assembly manual and overall quality of the kit will spoil you! Haven't tried the newer ones which have almost no point to point wiring at all, but they look ingenious. And based on previous experience, I'd expect measured performance to be good.
China is the wild west of cheap audio electronics, and I think if we lived there, we'd immediately dismiss a lot of stuff simply because it seemed too cheap to be any good. And IME, when you buy something like a $300 tube power amp from China chances are it's going to be pretty iffy. If you have access to an oscilloscope and signal generator, try feeding a 1 kHz square wave through them: If you get a pretty clean square wave at the outputs, voltages look about right for the type of tubes used, and noise and hum don't seem to be a problem, congratulations, enjoy your new purchase.
If, OTOH the output is visibly different (aside perhaps from being more rounded down) with overshoot or ringing at the leading edges of the waves, you've got your work cut out for you. Don't bother trying to swap tubes, cables and capacitors until you fix the basic faults.
Gut feeling about that cheap preamp board is: Avoid. 6 tubes for a lousy line stage? That sounds like 3 or 4 too many. Not a particular fan of tube rectifiers either.
China is the wild west of cheap audio electronics, and I think if we lived there, we'd immediately dismiss a lot of stuff simply because it seemed too cheap to be any good. And IME, when you buy something like a $300 tube power amp from China chances are it's going to be pretty iffy. If you have access to an oscilloscope and signal generator, try feeding a 1 kHz square wave through them: If you get a pretty clean square wave at the outputs, voltages look about right for the type of tubes used, and noise and hum don't seem to be a problem, congratulations, enjoy your new purchase.
If, OTOH the output is visibly different (aside perhaps from being more rounded down) with overshoot or ringing at the leading edges of the waves, you've got your work cut out for you. Don't bother trying to swap tubes, cables and capacitors until you fix the basic faults.
Gut feeling about that cheap preamp board is: Avoid. 6 tubes for a lousy line stage? That sounds like 3 or 4 too many. Not a particular fan of tube rectifiers either.
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