Chinese tube amp with fake caps?

[nanapana]

hi im Nick, i joined this site because today i bought a chinese tube amp from someone here in the us... and i saw alot of posts about bad or fake capacitors, and wanted to get some input as to the capacitors used in this amp, i havent recieved it yet, still shipping but seller had a photo of the electronics which isnt super clear, anyways any input would be greatly appreciated. tha k you guys! and possibly gals....😀 i dont know anything about electronics except theres alot of fake stuff coming from china and was a bit worried....ill update pic when i get it with high res....amp is a danyun audio model 6 uses 2a3b tubes...

[budm]

Re: Are these caps real or are fake LXY 1200uf@16volts

https://www.badcaps.net/forum/attach...0&d=1492575513
Those two blue lytics cap on the left board already have domed tops.
Those caps are sitting real close to those power resistors that are running hot, not good for the caps.

[Behemot]

Re: Fake Rubycon caps?

Look OK from those angles. Replace the blue ones.

Though you don't really need to SPAM the whole board with the same posts over and over, do you?

[nanapana]

Re: Fake Rubycon caps?

right, i just didnt know if i was posting i the right cattegories and didnt think id get a reply, what is it with the blue ones? what would you replace them with... i was also looking at so.e audio sites and they say rubycons arent very good for music, o of the top brands was rubycon black..or something lime that

[nanapana]

Re: Are these caps real or are fake LXY 1200uf@16volts

so what does it mean if they are domed? what would you suggest replacing them with what brand and resistance etc... i dont know anything about caps..

[budm]

Re: Are these caps real or are fake LXY 1200uf@16volts

so what does it mean if they are domed? what would you suggest replacing them with what brand and resistance etc... i dont know anything about caps..

It means those caps are bad, the internal pressure had built up high enough to cause the top to start doming if it is high enough then the top will open up to release the pressure.
http://www.elna.co.jp/en/capacitor/a...on/detail.html
Excert from the link:
12Be aware of necessary considerations regarding pressure vents.
1.In pressure valves, a portion of the case, etc., is made thin in order to prevent an explosion due to a buildup of internal pressure. This pressure build-up occurs when an excessive load is placed on the capacitor by the application's excessive voltage or voltage with the incorrect polarity. Note that the capacitor does not return to normal after the pressure vent has been activated. Therefore, the capacitor must be replaced.
2.For those components where the cases are equipped with pressure vents, please allow a space above the pressure vent during the design process. This must be done to avoid impediments to the pressure vent's operation.

So do you have tools for doing the repair, meter for testing capacitors, meter for checking Voltages and resistance, soldering tools, etc?

"what brand and resistance" You check capacitance of the cap (and also resistance of ESR), and resistance for resistor.
So are you capable of doing the proper repair?
Brand of caps, I use Panasonic caps for repair, but there are also other good brands from reputable suppliers also such as DIGIKEY, MOUSER.

[nanapana]

Re: Are these caps real or are fake LXY 1200uf@16volts

are there capacitors that are better for audio applications? and also if I were to replace them would the numbers have to be exactly like on whats written on those blue caps that are domed? Id love to replace the caps with better sounding ones, you also mentioned that they were too close to the other ones which get hot, whats a good way to resolve that?

[mariushm]

Re: Are these caps real or are fake LXY 1200uf@16volts

Use capacitors which are similar to the ones that were in circuit.

If the circuit used 85c rated capacitors or general purpose capacitors, don't just replace those with low esr or very low esr capacitors as their specifications may be too different.
Replace with better ones, like for example 105c rated capacitors but don't go overboard.

For example, maybe use something like Panasonic FC which is low ESR but not very low ESR like Panasonic FM or FR which are more suited for switching power supplies.

As for which are "better for audio applications" ... i'm not the type that believes capacitors in a power supply affect the sound quality.. maybe capacitors with way different specifications (like esr) in the audio path may change the sound ever so slightly.
For audio path, analogue stuff, maybe stay away from polymer capacitors, maybe stay away from very low esr capacitors, stay away from some/most ceramic capacitors (as they have very low esr and may exhibit microphonics) maybe consider replacing small capacitors (<1-10uF) with film/mica capacitors

See this video ... it may help :

https://www.youtube.com/watch?v=J0TjW_0xTJU

[Behemot]

Re: Are these caps real or are fake LXY 1200uf@16volts

Usually these bulk caps are standard or ordinary low-ESR (these are better - longer endurance). Than for the signal (small) caps it makes sense to use audio caps.

[Uranium-235]

Re: Fake Rubycon caps?

do these rubycons loom fake or legit?

they look real

those blue ones on the left side are bloating

[nanapana]

Re: Chinese tube amp with fake caps?

thank you all for all your advice i greatly appreciate it...uranium Silence!!!