CJ PREMIER 8A, 275 WATTS power on problem

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rehad
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CJ PREMIER 8A, 275 WATTS power on problem

Post by rehad »

Hi,

Since last week when i do power on sometimes i have a fuse blow up problem in my premier 8A amp. If its powered on the sound is ok , no problem until shutdown . The fuse is 500V 2A plate fuse on the back of the amp. Could it be a bad deformed socket the cause of this problem ? I have two sets of tubes which i think they are ok . And i can see that i can hear very nice and normal sound using both sets when the amp gets powered on normally.

What can be the cause of this strange problem you think ?

Thanks in advance
Reha
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Re: CJ PREMIER 8A, 275 WATTS power on problem

Post by rehad »

I bought the CJ Premier 8A 4 years ago,of course its a second hand amp for me. I wonder to know whether the fuses are the orijinal ones or not. Both of the CJ premier 8A monos have the same fast acting fuses. Are they the correct ones ?
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Re: CJ PREMIER 8A, 275 WATTS power on problem

Post by admin »

Have you tried testing the tubes to make sure they are ok? I know you mention that you have two sets, did you try switching them out, does the problem happen with a complete new set of tubes? It seems like in the official manual for the Premier 8 they emphasize the fuse blowing with tube failure.
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Re: CJ PREMIER 8A, 275 WATTS power on problem

Post by rehad »

Thanks, I will replace all the tubes of the working amplifier with the problematic amplifier tubes and will let you know the result.
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Re: CJ PREMIER 8A, 275 WATTS power on problem

Post by rehad »

Hello Again,

I don't have a test tool but when i replace the tubes they are working on the other amplifier . Tubes seem ok. I am not sure but it looks like this is an amplifier problem.

If i power up the amp without the tubes there is no problem. Can i install the tubes one by one and try to localize the problem ? Is this can cause some extra problems ?

Thanks
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Re: CJ PREMIER 8A, 275 WATTS power on problem

Post by admin »

I would try a new set of tubes in the affected amp. If you do not have a complete full set of tubes to switch out, getting 1 working tube and replacing each potential broken tube one at a time may also work. I would not power up the unit with missing tubes.
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Re: CJ PREMIER 8A, 275 WATTS power on problem

Post by Big Dog RJ »

Powering up the amp without tubes will blow the house down, plus probably set fire to a few things... DON'T try this ever!
Due to CJ's extensive experience in this industry, they have installed output transformer fuses, because they have come across these issues of people powering up amplifiers without tubes in them. the output fuses are also there to protect the Output transformers. In some other designs where they don't have this protection circuit (ex Audio Research) the entire output transformer would blow, costing quite a sum to fix up plus blowing out the neighbouring country side as well...

Sounds like there's a bad output tube on one of the monoblocks. It is very hard to tell which one, the only way is to replace all output tubes on that particular amp or have each tube checked with a tube tester. You would need to go to a tech place where they have a tube tester, this would be the easiest way to identify which tube rather than having to replace all eight! You also need to check that the output fuses are of correct type. Only CJ have these types, and have to be ordered either directly from CJ or through a CJ dealer.

BTW, this is the glory of having big monoblocks, when tubes need replacing, there is some big spending involved in these amps, and this is where your money goes. Another way to check this is when biasing, always check to see if each tube biases properly, if any tube is a bit fussy to bias then that's a weak tube that needs replacing. I did these bias checks with my monoblocks at the time but at the end of the day, at some point all tubes will require replacing. 16 output tubes plus 12 smaller signal tubes- that's a lot of tubes! Therefore, it is worth checking the bias once a month at least.
RJ
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