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Help!!! My Audioromy FU29 amplifier was fried!

tdmax

Member
2010-10-07 2:46 am
Hi Guys,

I am from Singapore and I really need help and advice on my fried audioromy Fu29 amp. The amp just got fried on its own last week.
And upon opening up the bottom plate, I saw 2 pieces of badly burned resistors.

Due to the resistors burned condition, I can't figure out the resistors value to get them replace. I really appreciate if some kind souls, having the same amp could open up the bottom casing and advice on the resistors color code and value, could help me out on this mess.

All help is greatly appreciated.

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When my amplifier arrived one of the Chinese FU29s was smashed which is why I substituted the QQV06-40s (obviously QQV03-20s are a little underpowered). They worked fine for several months until the amplifier failed. In the meantime I had acquired some RCA 829Bs but I never got round to using them. When I have fixed the relay problem I will try them. Thanks for the advice.
 
Hi All,

tdmax, did you ever find out wnat the problem was with your amp? I have an FU29 that looks slightly different to yours and the same resistor has burned out. the amp was running fine for 3 months and then just burned out one day.

occasionally the GU29 on the right would glow really hot even at low power levelsbut after turning it off and letting it cool down it would be fine again. but the last time it did this it made a really bad burning smell and I tool the cover off and found the same resistor burned!

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( i replaced the FU29's) and re biassed the amp via the manufacturers reccomendations

the resistor is a 1k 2 watt. I can replace it but think it will just fry again as there must be a reason it fried in the first place. I would greatly appreciate help as I know very little about electronics.

Thanks!
 
I am getting one of these amps too. Anyone figure out where in the circuit the resistors are that fail and why they are failing? Is it the poor quality Chinese FU29 toobes or just poor quality Chinese parts... resistors, etc, an oscillation or instability of some sort? The Metal work to me is worth the price of the amp alone. And... gotta like those designation letters on the toobe anyway... FU! Of course one can rebuild that amp with really decent parts for about another USD ~$100.00 and use Russian GU-29 or real RCA 829 toobes instead so it is still a bargain and I like the use of the XX-29 toobes for output. Please keep posting when you guys find the issue and I'll let you know when mine arrives...

Also, there is a thread on another forum concerning this same issue and they have noted that two different PCB's main exist.... Some of you may already know about this thread.

Mark
 
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What would it cost you to have that metal work done in Canada or the US though...? Of course I intend to keep the amp whole and to help solve the issues with it if someone else doesn't beat me to it. I intend to take mine a step at a time and a few steps further and rebuild the amp with high end components...

This brings up another interesting point... Has anyone using this amp pre-conditioned your FU-29 toobes before using it? Having built a number of OTL amps over the years I can tell you that doing this can eliminate much of the internal arcing that OTL OP toobes suffer from, especially with the 6C33's... Try at least 80 hours with the toobe filaments only at normal filament voltage... You may find that it helps as this bottle is somewhat similar to the 6C33.

Mark
 
I solved the issue with my amp. it turned out to be one of the tube sockets not connecting with one of the pins properly. this was due to using NOS tubes and not cleaning the corrosion of the pins. it shorted the heateramd red plated one of the tubes

i replaced the resistor and replaced the output tubes with another pair of gu29's its been fine ever since.

I have thought about rewiring the amp point to point. it's a fantastc sounding amp with masses of power.
 

costis_n

Member
2008-08-01 1:18 am
I am getting one of these amps too. Anyone figure out where in the circuit the resistors are that fail and why they are failing? Is it the poor quality Chinese FU29 toobes or just poor quality Chinese parts... resistors, etc, an oscillation or instability of some sort? The Metal work to me is worth the price of the amp alone. And... gotta like those designation letters on the toobe anyway... FU! Of course one can rebuild that amp with really decent parts for about another USD ~$100.00 and use Russian GU-29 or real RCA 829 toobes instead so it is still a bargain and I like the use of the XX-29 toobes for output. Please keep posting when you guys find the issue and I'll let you know when mine arrives...

Also, there is a thread on another forum concerning this same issue and they have noted that two different PCB's main exist.... Some of you may already know about this thread.

Mark

I have a question... what is a "toobe"?
:p