jwzhan

Burning fuse is completely the trafo's fault. One of the HV winding's resistance is less than 1ohm... (the one that's still good measured something like 90ohm) Yep, I've already put down the order for the 4700uF/35V pana caps already. It played music fine for like 30min... until the 25V caps overheated and blew... with 15-0-15, it's only 21V after the bridge, so it's well within the 25V rated voltage... 16-0-16... might be a little too close.. well. palchiu's trafo is rated for 16-0-16 @ 1A... but the load is too light for the trafo to drop the voltage to 16V... so it stayed at around 17V... which turned out to be to much (and I forgot the caps rating... never crossed my mind as I never had problem with the low voltage rail.)

KGSSHV back in service~ thanks to palchiu's generosity. That took way less time than I anticipated. Everything just went up in smoke no explosion no nothing.. just started smoking out of no where. seems to be the lower voltage rail's cap that died because of the excess voltage. One just opened and spewed a whole bunch of smoke.. the other is hot to the touch... I guess need to up it.... The caps are rated for 25V, palchiu's trafo is running on 17-0-17 which is 24V after the bridge... I guess that got too close for comfort... Just checked the HV rails and they are both fine. I got luck on this one... everything spewed out by the cap got blocked by the heatsink for 10m90s right next to it...

Andrew Jones Bookshelf is back again for $90.

I wish I had another hand to record it... but I was too busy trying to avoid crashing into his damn car. It could've made a great youtube video. Yeah... that guy really scared me a little... especially when he walked out with his penis exposed... because that's when I knew he definitely is a nutjob. Oh, he did realize his penis was out when he was walking towards my car... He was trying to stuff it back in while he was cursing at me. Thinking about it now... it's actually very funny... I'm very glad that it ended where it did... could've been much worse..

I was driving home today and a douchebag decided to do a "brake check" on me while I wasn't even close to him. He basically went to a complete stop from 50mph, I slammed my brake so hard that my ABS was engaged (his probably did too.) I drove right up to him and gave him and his girlfriend a middle finger, and you know what? He went psycho on me. He kept trying to cut me off and followed me into my residential area. He still tried to cut me off in the residential area, so I stopped.... The next thing I know he got out of his car with his FUCKING DICK HANGING OUT of his pants. WTF man. I backed up couple of yard, and he chased my car on foot, then I just went around him..... I guess that's why he thought I followed to close to him, because he wasn't paying goddamn attention to the road! His profile? A classic stereotypical white trash look that you'd see in movies with his again stereotypical blonde girl friend driving a not surprisingly stereotypical pick-up truck. My god, I thought those people only existed in movies. Apparently I'm way wrong. Also, this is one of those times that I wish I had a 9mm on me.

interesting... yours has a lower serial number than mine.. the one that I'm just about to send back tomorrow.

That's irrelevant to woo, because people are still going to buy them; in fact, I know there are buyers already lining up in the Chinese market to get this when available. Isn't "MOAR Power (aka. overkill)" the motto of the DIY community here? So, I don't see that as any problem.... problem is is the circuit up to snuff... well Birgir certainly doesn't think so... but that's not going to stop those suckers with thick wallets.

Now that is a great first post we have here. Congrats! They look very nice, and is that a PS1 that I'm seeing there?

I sent Richard another e-mail, and he said replacing the trafo for me is fine. (Maybe I mis-interpreted his tone in the last mail?) He also asked me to provide some detail. Why not, I guess it doesn't hurt to have a HV trafo for back up. We'll see if it will be strong enough. @insanity congrats on solving the problem.

well... he did not suggest replacing it. The trafo was ordered Aug 2012, so it's just a little over a year. I wasn't expecting him to replace it anyway. He was actually a little defensive when I told him that I just burned through his trafo and suggested to reinforce any future HV trafos.. It's because of his attitude that made me not want to buy more HV trafo from him... I know he definately can make high quality trafo that can withstand the abuse from these demanding amps... but I'm not sure he will, given his attitude.. Especially when he is already on the 4th edition trying to overcome the issue that has been present for a couple of years already. I have my doubts on the 4th edition trafo, so my replacement will not be from him. I don't know who to buy from yet.. Palchiu is kind enough to lend me his 450V 150mA trafo for now; however, that trafo runs on 110V, not US 120V, so it might result in too much heat. But if it's good enough, I might just get a 120V version from whoever he is getting his trafo from.

I sent an email to SumR regarding it. His answer did not instill confidence. He basically said he is now in the 4th (2013) edition of the trafo.. and he has made it overkill and it won't happen again.. Sounds familiar? I'm probably not going to get anothet HV trafo from them now.. eggil... I really do hope you got lucky.. because it sucks not to have an amp:(

hmm... burt smell is definately from the trafo... it wasn't even connected to the circuit when I tested it the second time... and I've had resistor burn problem... it didn't smell anything that strong..

I just unplugged it from the circuit and tested it... exactly the same thing happened except this time it happened even faster. It blew through the fuse almost immediately. The secondaries shot up to 300V and died. Also, there was that burnt smell and loud humming again. I'll use a low voltage trafo and the LTSpice model to check if there are any damages to the main circuit. I guess SumR does suck... and I retract what I said earlier in the therad about having problem with everything except the SumR... I now have had problem with every single component the in the amp.... (I must have jinxed it. )

Thanks for the advices. I think it's also worth to note that the first fuse blew during operation. I left it on during night because I was listening to it before I went to sleep and forgot to turn it off (not the first time.) When I woke up, the amp was off and the fuse was blown. I was also using 3A fuse tho with two thermistors in series to get the surge down. I was blowing through 3A fuses with only one thermistor. I used 4A this morning because I couldn't find the 3A fuse... The trafo was speced using Yun's BOM. 450V @ 125mA IIRC. There was always very faint hum with it, but I had to have my ear within inches of it to hear it. There was not loud hum whatsoever. ( It was humming loud this morning tho... I could hear it clearly standing 2 feet away from it.) Not going to add more skepticism now.. I'll report back when I have tested it.

nope. definately not the amp that's causing it. To be sure it wasn't the amp, I plugged in the esp950 and heard nothing. I've also been using esp950 with it for the past 2 to 3 months with out any problem. I'm also sure that only problems with PSU can cause the fuse to blow.. I'd be surprised if one amp board having problem can cause the fuse to blow.... If it were the PSU... the effect would show up on both channels. I also measured the output off sets and they were all okay. All LEDs are lit and there were no explosion. I also turned the amp on and off several times to hear the effect.. It only went away immediately after I cleaned off the debris... (although the actual cause may not be the debris I cleaned off apparently.) It's either a coincidence or an even larger coincidence.... The only thing I'm sure right now... is that my luck is down right fucked

oh... forgot to mention... along with everything there was also a strange burnt smell that I can't locate as well.... It took about 20~30 sec before the 4A slowblow blew. Transformer was cool to the touch after the fuse blew.

SumR... I will take a look at it when I get back from school today.... that was the first thing that crossed my mind as well... but I thought Richard already reinforced it... It has been running for at least 300hours without a hitch.

Well.... I wasn't planning to return it... but since my KGSSHV just went down... I'll probably just send it back now, since I don't have anything to drive it now. I couldn't keep both the 007mk1 and 009... EDIT: now come to think of it... since I already got rid of the hissing problem... even if I send it back now... they will probably not going to replace it because there are two scratches on the cup..... ehh... the last thing I want is to spend $200 on a round trip and wait 3 4months and have STAX send me back the exact same pair...

well my KGSSHV just blew a fuse.... sticking another fuse in there and it blew again. Before it blew, there was some strange physical humming... I couldn't identify from where... In input LEDs were lit along with the humming.... but that's about all the actions I got.... I couldn't identify any burn marks on the PSU board yet..

Shiiiiiiiit you need to re-read the welcome PM.

Man... I thought that it was resolved... apparently I was misinformed. I guess I will just have to wait and see. If it does, then off to RMA it goes... if not I guess I will just live with the two scratches... I hope you get yours back soon... they sure sound very nice when they are working...

Very nice! I just built a new computer at the beginning of the summer with a little lower spec. Corsair 600T case, Asus Z87-Pro, i5-4670K, GTX760-SC, Samsung 840Pro 256G, 1600MHz 4G*2, Seasonic X650, Pahtek PH-TC14PE CPU cooler. I was able to play all the games I had with settings maxed out. That includes Bioshock Infinite which was a fantastic game. Have fun and good luck!

I did not expect this from STAX. They are treading on thin ice here. QC of such low quality is just unacceptable for a $3600~$4500 headphone let along using damaged or possibly refurbed parts on new headphones. I think for most people, if they hear what I heard on the headphone.... they'd probably just send it back without a second thought... Most people wouldn't want to lift up the metal mesh under the ear pad and expose the driver assembly like that (given the stereotype of how fragile the electrostatic drivers are.) I know for sure that all Chinese 009 owners I know will not do that under any circumstances or let anyone other than STAX do that. Sloppiness in a Japanese factory is the last thing I'd expect... I would expect the world to end before that happens... but apparently I'm wrong... I really want to RMA it... but that'd cost $200 and god know how long... and I'm not even sure that I'll get a new one.. maybe I'll just get another refurb unit? Shit... STAX's image and reputation in my mind just went down the drain along with the debris underneath the metal mesh.

I'm at work right now, so I don't have it with me, but I'm sure the serial number is in the lower 2000... around 2250? maybe 2257? have to check when I get home. A quick search on google returned me serial number still in the mid 1000s during mid last year, so if it are an old unit, it must have not been that old. (if the serial numbers are consecutive and STAX didn't skip any... that means they have cranked out more than twice of units of their said annual production capacity. If this is an old stock... then they must have cranked out more than 3~4 times of their production capacity.)

May very well be. I received it very late yesterday, so I wasn't in the mood of doing a full body inspection. After doing it just now, I found two scratched on the right cup. I don't know what to make of it as of right now. Either their quality has gone down due to the inundation of orders for 009, or they are using refurb parts on new ones to save time... or maybe it's both.. anyway... it's bad.. (or is PJ selling at such a low price because they get refurb unit but not stating it? I certainly hope not. It's a bad business practice.) I guess the only good news now is that it still sounds darn good with KGSSHV..