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Author Topic: ENGL Fireball E625 Head white noise issue  (Read 993 times)

Psabin8951

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ENGL Fireball E625 Head white noise issue
« on: May 31, 2019, 03:07:20 AM »
A friend has just got hold of an ENGL Fireball E625 60 watt amp head. Looks in good condition and works but...
When ultra gain switch is turned on there is a large amount of white noise with the guitar sound.
If the guitar is plugged into the effects return and level set to full effect then there is no noise just pure guitar.
Any thoughts on the cause? The seller told him it has had new valves but obviously that's not gospel!

phatt

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Re: ENGL Fireball E625 Head white noise issue
« Reply #1 on: May 31, 2019, 04:30:57 AM »
If you are not used to really hi gain amps then it might seem like there is something wrong.
Generally a lot of hi gain amp circuits make a fair bit of noise and in a small room it can be quite disconcerting.
But these things are for LIVE gigs and that noise would be drowned out by the high sound levels of the band.
As long as everything works and no other odd quirks then likely the amp works fine.
On the other hand if you can't play the guitar louder than the background noise then you may need to look deeper.

I once tweaked a Laney all valve amp that had insane noise on the hi gain setting and it was factory stock design.
A couple of simple tweaks reduced the noise to a usable level. :tu:

A mate years back purchased his first ever valve amp,, he rang me and asked about the noise problem,, my answer was ,,Welcome to the world of valve amps,, they do tend to hum and buzz a lot. ;)
Phil.

Jazz P Bass

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Re: ENGL Fireball E625 Head white noise issue
« Reply #2 on: May 31, 2019, 10:35:29 AM »
The "Ultra" circuit simply lifts the tone control circuit (V2b) out of the signal path.
My feeling is that the tone control is mitigating the hiss.
If that is the case then the issue (if any) is in V1a/b and or V2a.


alessandro_gfdp

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Re: ENGL Fireball E625 Head white noise issue
« Reply #3 on: June 01, 2019, 03:10:45 AM »
no,the ultra channel uses 4 stages,the clean 3.
I had the same exact problem in the same amp,from a friend.
It developes over years,its not related to new or old tubes,in fact the old tubes were pretty good.Not related to anode or cathode resistors,changed all of them
I was running out of time and ended applying a coring circuit for noise reduction,but to me that is not the best solution.
Its all in the first 4 triodes,one thing i didn't do and maybe has value is to remove any trace of glue on the flat cables and the caps,and maybe substitute the filter caps,and wash the board and sockets with isoprop alcohol.

 

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