well, I will agree w/ Mwilson that JoLida manuf quality & parts quality leaves much to be desired. However, in my limited experience w/ a 502A, I cannot say that it as bad as Jupiterfish has experienced.
I'm the 3rd owner of this 502A & my amp was built around 1997 (confirmed by speaking to JoLida on the phone). I used the amp for 2 months in its original/stock form. Everything worked just fine & none of the controls made any noise. There was an annoying hum & it was discovered to be a design issue that I had fixed later on (you can read about it in my "bedroom system" page if you care to know more). The prev owner did have to repair 1 tube socket because he put too much pressure when inserting a tube (he confessed this at the time of the sale).
Internally, I've had much of orig parts have been upgraded & my friend who did the work did say that the PCB quality was poor in that the metal runners would peel off if too much heat was applied during soldering. I sort of expected this being manuf in China & sold in the USA at a certain low price point.
From a sonic point, the JoLida is poor sounding & I think that it is 'cuz of the ample global negative feedback it uses in the "ultra-linear" mode (boy, did I fall for this marketing term "ultra-linear"!!). All-the-same, it sounds quite good but it certainly not the best tube integrated at this price point.
Mwilson's suggestions of Rogue & Quicksilver are very good but they are all atleast 2X the JoLida price. I've seen some new Rogue integrateds advertised in Stereophile for about the same price as a new JoLida 502B but I've not heard them myself.
Other reasonable brands to consider are Primaluna & Unico.
There is magic in tube amps - make NO mistake! I'm sorry to read that your 1st foray had been marked w/ much pain. Hopefully you will persevere w/ tube power amps & will get to hear what they can offer.
I'm the 3rd owner of this 502A & my amp was built around 1997 (confirmed by speaking to JoLida on the phone). I used the amp for 2 months in its original/stock form. Everything worked just fine & none of the controls made any noise. There was an annoying hum & it was discovered to be a design issue that I had fixed later on (you can read about it in my "bedroom system" page if you care to know more). The prev owner did have to repair 1 tube socket because he put too much pressure when inserting a tube (he confessed this at the time of the sale).
Internally, I've had much of orig parts have been upgraded & my friend who did the work did say that the PCB quality was poor in that the metal runners would peel off if too much heat was applied during soldering. I sort of expected this being manuf in China & sold in the USA at a certain low price point.
From a sonic point, the JoLida is poor sounding & I think that it is 'cuz of the ample global negative feedback it uses in the "ultra-linear" mode (boy, did I fall for this marketing term "ultra-linear"!!). All-the-same, it sounds quite good but it certainly not the best tube integrated at this price point.
Mwilson's suggestions of Rogue & Quicksilver are very good but they are all atleast 2X the JoLida price. I've seen some new Rogue integrateds advertised in Stereophile for about the same price as a new JoLida 502B but I've not heard them myself.
Other reasonable brands to consider are Primaluna & Unico.
There is magic in tube amps - make NO mistake! I'm sorry to read that your 1st foray had been marked w/ much pain. Hopefully you will persevere w/ tube power amps & will get to hear what they can offer.