Have you ever seen a tube amp for so cheap

Jhayman

http://www.ebay.ca/itm/110V-220V-MS-10D-top-tube-amplifier-power-amplifier-nobsound-excellent-sound-/291484182030?pt=LH_DefaultDomain_0&hash=item43ddcfa60e

I don't understand how they can make a nice looking unit for so cheap..

Nightfall

That does seem awfully inexpensive. At that price I'd be worried about reliability.

mhardy6647

Well -- it appears to be a stereo "integrated" amplifier using 6N1 as drivers and 6P1 single-ended outputs.

The 6N1 is a dual triode -- not obvious if they use both sections of both tubes.
It is also not obvious whether the 6N1 is interchangeable, generically, with the Russian 6N1P or the 6922/6DJ8 family of twin triodes.

http://www.mif.pg.gda.pl/homepages/frank/sheets/095/6/6N1.pdf

The 6P1 is a little power tetrode in a 9-pin miniature envelope.

http://www.mif.pg.gda.pl/homepages/frank/sheets/095/6/6P1.pdf

Based on the above, I am inferring that these outputs are good for about 2.5 watts. Most folks don't have loudspeakers sensitive enough for that kind of power and a reasonable sized room at reasonable SPL. OK, I can -- so maybe I should say "most normal folks"

No substitutes for the 6P1, according to this site:
http://www.audiotubes.com/chinese.htm

The Chinese 6P1 and the Russian equivalent 6P1P also have no Western equal. The only other sub is the Russian 6N1N. These are all electrically like the USA 6AQ5, but have a 9 pin base, making adaptation difficult.

Safe to assume that the output transformers aren't world class in terms of materials or performance -- which has implications for power output, distortion, and frequency response (bandwidth).

The passive components (resistors, capacitors, power transformer, chokes, if any) are likewise probably generic or "table scraps" to keep costs down. Reliability and quality could both be suspect.

The VU meter is cute but probably useless (unless it allows something else to be measured).

I assume (?) the tone controls are passive -- unless there is some solid state circuitry under the hood. We don't know if the outputs are triode or used as tetrodes; we also don't know whether there is feedback used in the outputs (e.g., ultra-linear topology) or globally -- so we don't know how much gain the amp has (and, thus, what it'll take to drive it to full output). Those tone controls may (??) eat up a fair amount of the available gain.

Hard to say whether the output tubes drive the headphone output as well as the speaker outputs.

Bottom line -- You get what you pay for. It might be a fun toy for the total outlay of $159 (Canadian -- am I reading that right?). I might buy one to play with -- but I could troubleshoot and rebuild it if it died or if it arrived nonworking. I'd see something like this as a much better investment for someone comfortable with DIY/repair than someone who really just wants plug-and-play (and, of course, has loudspeakers of 100 dB-plus sensitivity).

Just opinions, though, of course.

mhardy6647

oh -- but wait, there's more:
http://members.iinet.net.au/~cool386/jaycar/jaycar.html





There's more -- and less -- to this amplifier than meets the eye.

I'd say "pass".

[Deleted User]

tip of the cap to mhardy.
I'm happy operating the coffee machine in the morning.

Jhayman

Lol, redtednugent awesome dissection of the amp unseen...
mhardy Thanks for the pics and already having one cracked open, I was just curious as to how can it be made and offered for less than $90...
Glad you had one..

voltz

I like the wood work on some of his amps but not sure I like how its wired.

http://www.ebay.ca/itm/Nobsound-6J8P-EL34-Single-ended-Class-A-Tube-Amplifier-Hifi-DIY-Manual-10W-10W/271837403759?_trksid=p2047675.c100009.m1982&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=20140620091411&meid=0df665a07f6e4adca1c12b50f14975ab&pid=100009&rk=1&rkt=10&mehot=lo&sd=291484182030

cnh

I've seen tons of Chinese fakes both here and in the country of origin. The Chinese audio market is still young and kind of like the old West, full of snake oil salesmen, etc. However some of the better known Chinese valve amps are fine, more than fine.

But my first take when I saw the price above was: let's make an SS amp and put some glowing tubes in it then sell it is as a tube amp! It's as simple as that, or for those of you who love Technese, there is the full text in the link Mark provided above. Really, I'm not looking to learn what I did not learn in electric shop in the 8th grade. Too many other things to process, limited time and less and less storage capacity in the old brain. They used to say wisdom comes with age, now it's just a matter of how much can you "remember" not how well can you imagine, create? We herald the Magister Ludis of the world and forget such as they got bored with their Glass Bead Game and sought a more humble calling.

mhardy6647

Oh, no -- I never had one. I just looked around a little on this thing that some call... the internet.

Conrad Luxman

This wonderful little amp is not a fake nor is it a Chinese fraud. It is the unfortunate victim of language and translation problems.

This amp is actually a 50W per channel hybrid Class AB amp (using 4 Fairchild TIP42C transistors) with a tube pre-amp stage.

Really nice sound and output. Considering the size it is perfect for small room applications, and will drive a reasonably efficient speaker at ample levels.

The hybrid design, tubes up front for voltage, transistors for output is a tried and true design that brings the best of both worlds together. Tube sound, SS power.

The four tubes are all preamp tubes, the output power comes from the transistors. The larger of the two tube types are 6P1's, they are NOT the equivalent of the EL-84 which is a power tube. It is a preamp tube and only compatible with the Chinese original 6P1's or the Russian equivalent 6P1P's, of which the older milspec ones are excellent, cheap, and available.

mhardy6647

Well... the Russian 6p1p (6П1П) certainly appears to be a beam power tube...
http://tdsl.duncanamps.com/pdf/6v6vm.pdf



As best I can tell, it's broadly similar to a 6AQ5 but with a nine-pin base (and larger envelope); thus more or less a 6V6 inside.

http://www.audiotubes.com/chinese.htm

The Chinese 6P1 and the Russian equivalent 6P1P also have no Western equal. The only other sub is the Russian 6N1N. These are all electrically like the USA 6AQ5, but have a 9 pin base, making adaptation difficult.

Just sayin', you know?

heiney9

Many, many times these inexpensively made Chinese amps have poor construction, poor parts, dubious design circuits, overall "iffy". I'd stay away from the ultra cheap stuff as you are just asking for trouble unless you are a well trained electronics guru.

So many of these ultra cheap units are either misrepresented, sound poor and in some instances catch fire or ruin tubes.

You get what you pay for. You will have no tech support, or it will be expensive sending it back and forth.

You get what you pay for in many instances with the ultra cheap stuff. Occasionally and I mean very seldom will you find a gem amongst the turds. These look like turds to me and I've been around the block with relatively inexpensive tube integrateds from China

H9

heiney9

6N1 signal tube can be substituted with the ECC85/6AQ8 NOT (6922/6DJ8). My little Dared clone uses those and there are some very fine sounding ECC85/6AQ8 variants.

heiney9

Also if this little amp uses transistors instead of tubes for power output why are there separate 4 and 8 ohm taps? Would not be necessary for transistor output. They are there to mislead one into thinking it has a tube output, plain and simple.

H9

mhardy6647

heiney9 wrote: »

... I'd stay away from the ultra cheap stuff as you are just asking for trouble unless you are a well trained electronics guru.
...

H9

... and, by and large, the gurus will avoid such stuff like the plague.