chinese tube amp

[TubeHead Johnny]

I've been using JJ 12AX7S's and 12AU7's and never had a complaint. They're dead quiet with no humming or hissing. Excellent sound from top to bottom, with no glare, coloration or harshness. The best part is they're inexpensive ($10.00) and you can get them balanced and matched for only $4.00 more at TubeDepot.

For KT-88's I use Electro Harmonix. They've got a deep, powerful bass, highly detailed and realistic mids with absolutely no harshness on top. Very silky. Ive tried JJ's and SED's, but the EH's seem to have a clearer and cleaner top.

And for the EL84 that blows fuses, you may first want to take the bottom cover (with the cord unplugged of course) and check for burned up components. It's probably something really simple.

~~~Johnny~~~

[squirtacious]

I had just assumed the electroharmonic tubes were not so great cuz of the reasonable cost. I will now include them in my search. I did pop the bottom cover off of the el84 amp and saw no damage but I didn't pull the circuit board loose to see the other side of it. I didn't pull the transformers either, I'll keep digging. thanks

[squirtacious]

I finally got ahold of the guy who sold me these things. He happily refunded me $220. for the missing tubes. Seeing how I probably would have upgraded them anyway, I'm actually ahead! I paid $46. and $151. for the two amps so now I pretty much got them for free plus shipping. So I ended up buying new cryo treated electro harmonics for $290. If these amps are ok I should be a very happy camper. As for the other el84 amp I think I'll just take it in.

[TubeHead Johnny]

For the EL84 amp, you may want to check the output tubes before you take it to the shop. A few years back, Chinese output tubes had a bad reputation for shorting out. Try putting in another fuse, then pull all the EL84's. If the fuse doesn't blow, it's the tubes. EL84 tubes are very inexpensive these days, and you can get a good quad for $40 or less. If the fuse does blow, it can be something serious, like a shorted power trannie.

~~~John~~~

[squirtacious]

I'll bet your right. I did notice one of the input tubes got bright right away then pop! I figured that I would try a new fuse then power up with no tubes. But i didn't think that would prove anything for sure. So I didn't, but now I will. Thanks

[Cycline3]

Originally posted by squirtacious
I'll bet your right. I did notice one of the input tubes got bright right away then pop!

Well.. maybe.. maybe not.. some heaters just do that.. glow really bright and then calm down... hard to say.... have you decided what to do? Fix it yourself or get it fixed? I do some repair work.. and that's why I said it before.. Im sure you could find someone on this board to fix it for you.. (not just me mind you... ) If you do choose to do it yourself --- with a digital camera im sure we could all chip in...
-Sean

[Hi-Q]

Just a reminder, Most Chinese amps do not seem to have bleed resistors fitted. If you power up the amp with no tubes fitted then the HT (B+) line may be left fully charged and give quite a nasty surprise. If you are going to go probing, best to check/discharge the B+ with for example a well insulated high watt 100 Ohm resistor.
Play safe, take care.
Les

[18thell]

recently, I've bought a Chinese tube amp. it's junk, not worth a penny but cost me hundreds of shilling. If you ever bought any equipment manufacturer ed by Chinese, think about Mattel, all the products either returned or discarded, total lost!!!.

They can produced an amplifier by sticking the filter can caps. with hotmelt glue, tubes were digged out from **** yard, ( War in Vietnam between US and China half decade ago ) the wiring is owful and horrible. imagine a messed up spider web. When U power up the unit after half an hour, the tranny gets hot and dissolve the hotmelt which used to position the filter can caps. Then the Hi -voltage terminal of the cap. shorted together and give a " bang ", then followed with a stinky smell like evaporating ***** and urine, this is the result from the heating up tubes digged out from **** yard, after these, smoke in white colour came out from the overheated power transformer, due to the spider web wiring collapsed and cause shorted cct. The tubes socket they used were disassembled from scraped junk yard equipment, thunder and sparking noise generated between the tube and the socket contact when it was working. Such amplifier I still have to paid for the garbage man to remove the unit away. None of the component left can be used. Even the output tranny both were internal partially shorted cause by the reused copper wire. Pocket Tragedy and money lost !!!

If you people want to loose money, consider buy Chinese Amplifiers or their products.

[poynton]

Originally posted by 18thell
recently, I've bought a Chinese tube amp.

Name the amp???

Pictures ?

[18thell]

Originally posted by squirtacious
I'll bet your right. I did notice one of the input tubes got bright right away then pop! I figured that I would try a new fuse then power up with no tubes. But i didn't think that would prove anything for sure. So I didn't, but now I will. Thanks

This kind of symptom I experienced. Some tube gives bright filiament when lid then dimmed. this because the filiament inside the cathode sleeve partially shorted and back to normal after heated up. If you disassemble a bad tube, ( not filiament failure ) you will see the tungsten wire was very fine and fragile, then wired up in a spring shaped coil, then flipped several times back and forth, usually the short took place between the flipped angles. After heated up, the tungsten wire expanded and released the shorted angle, then the tube becomes normal.