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PostPosted: July 4th, 2017, 5:27 pm 
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So my Pacific creek E34I integrated tube amp is kind of acting up on me.

It performed flawlessly for me for several years, until I tried out some new tubes and one of the tubes arced on me.

Since then the amplifier has been making some popping noises shortly after power up, even after I have returned to the tubes I have had no problems with.

I haven't actually cracked it open yet, but from what I understand, the only thing in the amp is tubes, resistors, and capacitors. From what I know the amp is about 8-10 years old.

I would like to open it up and check all the parts, but I have never done this before, so I need a little instruction. I suspect testing a resistor is as easy as using a multimeter, and testing a capacitor requires another meter, but that's relatively easy to obtain. My first inclination is just to check all the parts and verify their values are the same as the values stated on the part itself, or the schematic.

If I find any funny values, then I would suspect that is what is causing the problem.

Assuming the amplifier is designed soundly, is it any more complicated than this?

Thanks,

Chris


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PostPosted: July 4th, 2017, 7:12 pm 
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Joined: August 16th, 2013, 8:52 pm
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Location: Pikesville
There is probably capacitors and resistors in parallel, so you need to calculate the total value....
See if you get clean DC as well....

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PostPosted: July 5th, 2017, 7:17 am 
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how old are the driver tubes?

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PostPosted: July 5th, 2017, 4:56 pm 
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Driver tubes were about two years old when I swapped in the new set that arced on me.

For those two years I had zero issues, but after the arcing tube, when I returned to the reliable tubes, I was occasionally hearing some popping noises.

I recently put in brand new driver tubes a couple weeks ago, and they have popped on me during power up twice now.


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PostPosted: July 5th, 2017, 5:19 pm 
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I might be a little confused.

Are the driver tubes the Output/Power tubes ( the four big tubes), or the ones in the preamp pre-driver section (the four little tubes)?

Those are approx. 2 years too with no issues during those 2 years.


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PostPosted: July 5th, 2017, 8:08 pm 
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The "Driver Tubes" that Cogito is asking about are the smaller (probably 6SN7-type) tubes in the center of the amp.
The EL-34 tubes on the periphery would be called Power tubes or Output tubes.

To be clear, the EL-34 power tubes are what arced, right?

chris1973 wrote:
I might be a little confused.

Are the driver tubes the Output/Power tubes ( the four big tubes), or the ones in the preamp pre-driver section (the four little tubes)?

Those are approx. 2 years too with no issues during those 2 years.


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PostPosted: July 5th, 2017, 8:45 pm 
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Yes, the EL34's are the ones that arced. (Psvane Phillips Holland Replicas)

I got rid of them, and went back to the tubes that had served me with no issues for the previous couple of years (Psvane UK Replicas)

I have heard a couple funny noises since I went back to the UK tubes.

I couldn't stay away from the Holland tubes however, because they sounded a lot better, so I just recently bought another set.

I haven't seen any arcs in any of these tubes, but the new Holland tubes have made popping noises twice, that sounded just like the arcing tube. The only difference is that when the tube arced, the bias got really screwy, especially in that tube, but all the tubes were off considerably after the incident.

With the new set of Holland tubes, I have checked the bias every time after I hear a pop, and it's not really messed up.


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PostPosted: July 5th, 2017, 9:09 pm 
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Few suggestions.

1. Stop adjusting the bias.
2. Determine if your driver tubes are the problem. Slightly tap on each tube and see if you hear any noises from the speakers. If you do, tube is probably microphonic, replace all four.
3. Swap the right channel and left channel drivers. If the crackling sound follows the tubes, you have the answer.
4. Cold solder. check if tapping on the sides of the Amp chassis generates crackling sound. If it does, look for loose solder joints and fix them.
5. If you removed the power tubes too many times, the contacts in the sockets might loosened. Try tapping on them too.
6. If nothing helps, then get into looking at resistors and caps.

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PostPosted: July 5th, 2017, 10:43 pm 
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That's cool!

I'll try all those things.

Thanks Sashi


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PostPosted: July 6th, 2017, 12:14 pm 
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Joined: April 22nd, 2013, 12:58 pm
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You also might want to look for small carbon traces in and around the sockets, which may have been created during the arcing incident.


chris1973 wrote:
That's cool!

I'll try all those things.

Thanks Sashi


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