Smoking HOT X-BoSoZ HELP!

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So i'm listening to my pre-amp that has worked for a while now, and i smell this weird hot smell, i open up my pre-amp to see that 4 resistors have goten so hot that they de-soldered from the board :( the pre-amp is working but these babys get hot, how come ?


Pictures can be here,


Pic 1
Pic 2
Pic 3

This is upsetting, Ive spent way over 400$ on this, has eny one's done this ?

Yes the resistors are elevated. Do i now have to buy a new one ? UGG!
 
wow!

Hey, those resistors look pretty warm!

Even more impressive is that they look to be two 1.5K 3 watters in parallel to reduce the power consumption on each! Are they R1/R6 and R7/R2 on the X-CCS-BOSOZ schematic...as used by Kari here? If not what are they?

More importantly what voltage do you get across them and what are the PS rails? If your circ is not like the linked schematic- what schematic are you using?

Mine runs hot, but not that hot...

I'm sure this can be figured out with some more info.
 
Formerly "jh6you". R.I.P.
Joined 2006
jleaman said:
So i'm listening to my pre-amp that has worked for a while now, and i smell this weird hot smell, i open up my pre-amp to see that 4 resistors have goten so hot that they de-soldered from the board :( the pre-amp is working but these babys get hot, how come ?



If the amp works flawless, what should be the advice, except saying that there is too large number of thru-R currents?


:darkside:
 
Re: wow!

lgreen said:
Hey, those resistors look pretty warm!

Even more impressive is that they look to be two 1.5K 3 watters in parallel to reduce the power consumption on each! Are they R1/R6 and R7/R2 on the X-CCS-BOSOZ schematic...as used by Kari here? If not what are they?

More importantly what voltage do you get across them and what are the PS rails? If your circ is not like the linked schematic- what schematic are you using?

Mine runs hot, but not that hot...

I'm sure this can be figured out with some more info.


Yes they are the 1.5k @ 3w it's weird only one side of the set of resistors gets hot.
 
Twisted?

what is the voltage across those resistors? How does that compare to the other channel? That's a Twisted Pear preamp right? Maybe those guys and chime in.

Looks like you have some melted capacitors too, hmm... that damage looks like a soldering iron "accident."
 
I had a similar problem when I first built my xbosoz, same twisted boards.

In my case I measured a huge discrepancy between L and R channel voltages on those resistors. The "root cause" seemed to be shorting of fets. I changed the mica insulators and problem solved.

Just a newbie so be gentle if this not make any sense but I have been running my xbosoz for two weeks now no issues.

pathmark
 
I had some resistors in one of my Balanced Zen Linestage boards that got hot like that while I was doing some testing. I can't remember what the specific issue was, but I will try to find the board and see if I can figure out what the problem was. It is easy remember which board (of 4) it was -- it has similarly browned resistors.

Posting your power supply voltages, a schematic, and confirmation that those resistors are the ones that lie between the mosfet drains and the +V supply rail would start.

The fact that you show a 22ohm resistor with dripped solder kind of indicates that you were drawing really high curent (for a preamp). I assume taht resistor is the one that lies between the +V rail and the on board PS supply cap?

JJ
 
Re: Twisted?

lgreen said:
what is the voltage across those resistors? How does that compare to the other channel? That's a Twisted Pear preamp right? Maybe those guys and chime in.

Looks like you have some melted capacitors too, hmm... that damage looks like a soldering iron "accident."


Across those resistors i get 49V.
 
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