Bogner Helios is fine

[misterspockyall]

Lots of tone testing today on my 100w Helios. With volume maybe loud enough for a soft drummer, my guitar with EMG’s sounds like the bottom end is fuzzy like square wave distortion, flubby. When I hit my boost pedal, I would then lose top end and quickly all sound would fizzle out, and fade back in when I turn off the boost. Boost and guitar work ok on other amps.

EMG battery? Something messed up on the front end of my Helios? Tubes?

 

[FourT6and2]

Yeah, check all the batteries involved. Have you tried just the guitar straight in? Lose all the effects and pedals and whatnot. Nothing else plugged in, just the guitar. If it still does that, first suspect would be tubes. I know when the battery in my delay pedal starts to go out, the sound begins to fade and fizzle out until the battery completely dies. So check your guitar battery too if you've got actives.

 

[misterspockyall]

Tested new batteries, bottom line, any boosting of the front end causes the square wave distortion on the low end to the frequencies. I can even hear it when I roll the gain on the amp back. Sounds like a raspy fuzz pedal.

I pulled off the back cover to start rolling tubes, and I don't see any bias ports. The EL34 quad in the amp are labeled "23 4.8". The other known good quad I have are around 60 current, 8500 trans. I don't know how these numbers relate or how to proceed.

I own a multimeter, am fairly handy and can follow instructions if needed

 

[FourT6and2]

Please remove any pedals and effects from the signal chain first. Just the guitar straight into the amp.

If the amp sounds fine like that, then it's the pedal.
If the amp does not sound fine like that, then try replacing preamp tubes.
If the amp does not sound fine like that, then try replacing the power tubes with a NEW set.

It's also rare, but maybe you're getting DC on your guitar from V1 grid/plate. But I would check the other things first.

 

[misterspockyall]

Please remove any pedals and effects from the signal chain first. Just the guitar straight into the amp.

If the amp sounds fine like that, then it's the pedal.
If the amp does not sound fine like that, then try replacing preamp tubes.
If the amp does not sound fine like that, then try replacing the power tubes with a NEW set.

It's also rare, but maybe you're getting DC on your guitar from V1 grid/plate. But I would check the other things first.

I followed what you said the first time, leaving step 2. I’ll have some time to try this hopefully soon!

 

[misterspockyall]

Rolled a known good Tung Sol preamp tube thru each slot, no changes in problem. On to Power tubes..

 

[misterspockyall]

And replaced all 4 power tubes with an EL34 quad that Bogner sent to me. Same deal. If I hit the front with too much boost, it will literally fizzle out and not make a sound when I play. Even just with the emg's, bass heavy bar chords sound like a fuzz pedal.

 

[FourT6and2]

What's your bias set at? Could be crossover distortion. Please measure plate voltage and report bias setting.

If bias checks out, could be any number of things. Will need to go through the amp and make sure there are no bad solder joints and no bad resistors/caps. Start with the filter caps. If you don't know how to do this, you're better off taking it to a tech.

 

[NewReligion]

And replaced all 4 power tubes with an EL34 quad that Bogner sent to me. Same deal. If I hit the front with too much boost, it will literally fizzle out and not make a sound when I play. Even just with the emg's, bass heavy bar chords sound like a fuzz pedal.

Call and ask for Charlie at Bogner. Super cool guy. He helped me out with a 2006 Shiva in 2011. He well may tell you something we are not aware of.

phone: +1 818.765.8929

My $.02

David...♫

 

[misterspockyall]

David- I reached out last night, Charlie has been great with questions and mods in the past on my Uberschall.

FourT6and2- I'm going to do my homework on how to check that today. I don't know a ton, but have modded and rehoused pedals before, so hopefully this is within my grasp.

Before I go too far down the rabbit hole, I was swapping in 1 preamp tube at a time. Is it possible that multiples are bad and I should try a whole set?

 

[FourT6and2]

I was swapping in 1 preamp tube at a time. Is it possible that multiples are bad and I should try a whole set?

Yes, I would give it a try.

 

[MetalHeadMike]

Isn't this brand new? If so, I'd just exchange it.

 

[misterspockyall]

Isn't this brand new? If so, I'd just exchange it.

Bought used :/ Looked perfect so I took a swing on it from eBay. I blew the mains fuse weeks ago when I had the loop jumpered to control volume to keep the channel volume high. But I replaced the fuse at Charley's suggestion and the amp performed flawlessly for weeks after with many many hours of use. I guess it could be related, but I only know enough to be dangerous with these things.

Amp modding/repair is on my bucket list, but I know I have a lot of homework to do before I go poking around with the chassis pulled. Hell, I don't even know how to bias this thing without the external points and pot. It's amazing how much I think I know until crap hits the fan in the real world

 

[MetalHeadMike]

Isn't this brand new? If so, I'd just exchange it.

Bought used :/ Looked perfect so I took a swing on it from eBay. I blew the mains fuse weeks ago when I had the loop jumpered to control volume to keep the channel volume high. But I replaced the fuse at Charley's suggestion and the amp performed flawlessly for weeks after with many many hours of use. I guess it could be related, but I only know enough to be dangerous with these things.

Amp modding/repair is on my bucket list, but I know I have a lot of homework to do before I go poking around with the chassis pulled. Hell, I don't even know how to bias this thing without the external points and pot. It's amazing how much I think I know until crap hits the fan in the real world

My bad, I thought you grabbed this from Sweetwater a while back.

 

[misterspockyall]

My bad, I thought you grabbed this from Sweetwater a while back.

Yeahhhh somewhere that thread turned into I got a Helios on eBay, and ended up buying a Goldfinger Superlead from Sweetwater lol. It's been a busy winter.

 

[MetalHeadMike]

My bad, I thought you grabbed this from Sweetwater a while back.

Yeahhhh somewhere that thread turned into I got a Helios on eBay, and ended up buying a Goldfinger Superlead from Sweetwater lol. It's been a busy winter.

Yes you have.....

 

[misterspockyall]

In a hurry to rule out more issues, I swung by the local Sam Ash to get 5 JJ ECC83 tubes. I just opened them to swap them out in my amp, 3 of them were Fender labelled Sovteks!

I swear at the end of this I'm just going to switch to drums.

Scrounged together 5 good ECC83s to put in the Helios, fuzzy/fizzy low end and dies altogether when I boost it. I'm punting to the local tech. Thank you to everyone who contributed, this forum is priceless.

 

[NewReligion]

In a hurry to rule out more issues, I swung by the local Sam Ash to get 5 JJ ECC83 tubes. I just opened them to swap them out in my amp, 3 of them were Fender labelled Sovteks!

I swear at the end of this I'm just going to switch to drums.

Scrounged together 5 good ECC83s to put in the Helios, fuzzy/fizzy low end and dies altogether when I boost it. I'm punting to the local tech. Thank you to everyone who contributed, this forum is priceless.

Good luck and please keep us posted.

David

 

[misterspockyall]

Good luck and please keep us posted.

David

Thanks and will do, I think it’s good to post findings to help out with searches later.

 

[FourT6and2]

Yeah I'd like to know what the actual problem turns out to be. So keep us updated.