Bogner Fish/Rack problem diagnosis

  • Thread starter Thread starter Hail Satin
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Hail Satin

Hail Satin

Member
Hello Everybody.

Sorry in advance for the long winded post.

Can someone point me in the "right" direction to diagnose a problem I'm having
with my rack?

Recently, I've been getting "noise/popping sounds" from the clean channel of my fish.
It starts happening after about 10-15 minutes. After the 15 minute mark the clean
channel begins to cut out completely (no volume). I switch channels and the clean
channel returns (only to cut out again). It's definitely a "crackling" sound.

Here's the gear rundown:

Fish
GCX
Intellifex
STD-1
Power amp.
Wired with George L cables (I've re-trimmed them and checked them with
a mulitmeter).

Could this be something as simple as a preamp tube (assuming that it's the preamp)?

I've switched the order of the effects in the gcx loops with the same results.

I've removed the gcx from the signal and ran the effects straight from the preamp
outs and I didn't get any noise/popping sounds (but I didn't play it to the 15 minute
mark).

I've even switched to another intellifex with the same results.

Any thoughts (and thanks for any replies)

Joe
 
What I would do is try just the FIsh into the poweramp just to make sure its one of them. Play it until it makes the noise or for about an hour just to make sure. If it occurring within 15 minutes, 1 hr of playing will give you plenty of time and you can be 99% sure with that time frame.

Do you have any other amps at all?
You can always run the fish into the effects loop in of another amp to check the preamp with a different poweramp, and also you can run the effects loop out of an amp head into the poweramp just to make sure the poweramp isnt causing the problem. That will narrow it down between the two. From there, I would start to swap tubes to the piece of gear causing the issue.

It could be something as simple as a tube, or it could be a bad solder joint among many other things. I would think its a simple tube issue though.
 
Next step is to run the following signal path:

Guitar --> Fish --> Power Amp --> Cabinet

Play through it for as long as necessary for the "issue" to normally occur. If it doesn't happen, looks like it's not the Fish OR the power amp. If it does happen, pop the lid of the Fish and change out the Country (read: clean) channel's preamp tubes. You can see which preamp tubes (V1 and V8) relate to the Country channel on Bogner's website:

http://www.bogneramplification.com/cust ... reInfo.php

Good luck!
 
Hey guys

Thanks for the input. I'll give it a shot tomorrow
and will post the results.

Thanks once again!

Joe
 
since it is time based and not a direct problem the first and always the first culprit to diagnose is both pre and power tubes. IMHO you are due for a full retube in the preamp. since the preamp creates sounds fine and the problem is once again a time based problem on a specific channel, retube it with a known working set of tubes and it will most likely solve your problem. tubes do not last forever and will go at any moment just like light bulbs.
 
Definitely a preamp tube and in the case of the Fish, it is V1. This is the only tube corresponding to the clean channel. It is not an input tube for the others.

Steve
 
Hey All!

Thanks so much for your replies and suggestions.

Initially I swapped out the tubes in positions 1 (and eventually 8) and still had the same issue.
Subsequently I changed all of the preamp tubes out and am still having the "crackling"/clean
channel cutting out issue (though it seems to occur less when I run the pre straight
into the power amp). It will make noise and cut out eventually.

I switched to my 295 power amp and only had a chance to run it for about 30 minutes
and I didn't notice any "crackling" sounds nor did the clean channel cut out.

Now my question is: If it's the power amp causing this issue, Any thoughts as to which tubes
could be causing this (the el84's or the 12ax7's)?

Once again, thanks so much for all of the advice and insight.

Joe
 
Hail Satin":1eisrmrx said:
Hey All!

Thanks so much for your replies and suggestions.

Initially I swapped out the tubes in positions 1 (and eventually 8) and still had the same issue.
Subsequently I changed all of the preamp tubes out and am still having the "crackling"/clean
channel cutting out issue (though it seems to occur less when I run the pre straight
into the power amp). It will make noise and cut out eventually.

I switched to my 295 power amp and only had a chance to run it for about 30 minutes
and I didn't notice any "crackling" sounds nor did the clean channel cut out.

Now my question is: If it's the power amp causing this issue, Any thoughts as to which tubes
could be causing this (the el84's or the 12ax7's)?

Once again, thanks so much for all of the advice and insight.

Joe
Click to expand...

if you're slamming the front end of the poweramp hard with any boosts, i would bet the 12ax7's used as drivers for tone controls. most likely though i would bet its an EL84 tube first just because they are extremely finicky by nature. rock solid and EL84 are never in the same sentence, i would take one known working EL84 tube and try to isolate which one is causing the problem.

it also would not hurt to borrow a few of your new tubes, stick them in the poweramp so you can make sure its not those to begin with, if the problem still occurs, then start checking each powertube at a time until you find the culprit. once you're done, stick the new ones back in the fish and start saving for a retube on the power end when you get the chance.

thats the downside of owning tubed amplifiers. they require maintence where solid state does not.
 
Hey all.

Thanks for all of your replies and suggestions.

Here's where she stands:

It's not the power amp. The crackling/pops continue even when the power amp is
not on (as evidenced by the intellifex input led's)

Unless the tubes I used to replace the originals were defective, it doesn't look like
it's the preamp tubes.

Time to give Charlie @ Bogner a shout.

Once again, many thanks guys. I appreciate the advice and input.

Joe
 
FWIW i retubed with six 12ax7WC's once before doing a few modifications to an amplifier. after getting awkward results and readings, double checking the math, reflowing solder points, and double checking the circuit, i replaced all of the tubes.

all 6 of the new 12AX7WC's were microphonic.

Just because you buy them new does not mean they are guaranteed to work. When i said a known working tube, i meant a known working tube - new or old. never assume ;)

good job on isolating it to the preamp itself - at least you have some direction as to the culprit - keep us updated on what you find out!
 
I used an old set of boogie preamp tubes that I pulled from my quad
ages ago. They worked fine back then but...you never know!

I'm over chasing the ghost in the machine. Hopefully Charlie can work
some magic.

Thanks guys!
 
Also, the last tube, V8, is an output driver tube which could be a culprit as it sums signal to the power amp. It is highly unlikely that there is anything wrong in the Fish unless it got knocked around. If you ever need to tame the output of a Fish, you can run a 12AT7 here.

Steve
 
steve_k":21vm4x0a said:
It is highly unlikely that there is anything wrong in the Fish unless it got knocked around.
Click to expand...

+1

051007_robot_fish.jpg
=
 
Hey All

Thanks for the suggestions. I did another swap of tubes 1 and 8 with known working
tubes and the problem still persisted.

I dropped it off at bogner this week and I showed ted (?) my cell phone vid of what it was
doing and his first words were "power supply"...

I'll post the results when I get the amp back.

Thanks again guys!

Joe
 
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