Nasty Hum out of JR Terror

Orange Amps General Forum

Moderator: bclaire

Post Reply
Hogie34
New Member
Posts: 13
Joined: Sat Apr 25, 2015 7:34 pm
Location: The High Desert

Nasty Hum out of JR Terror

Post by Hogie34 » Fri Jun 19, 2015 9:20 pm

Ok, so I looked in the tube layout section so that I could describe this correctly but there is no layout for the JR Terror in that thread. So, I'm just gonna give it a shot here. What I believe to be stage 1-2 or V1 of the 12ax7 positions ( looking at the front of the amp, furthest tube to the right) no matter what tube I roll into that position, it is seriously micro phonic . Tap on the tube, you can hear it in the speaker.

I've tried new tubes in that spot, sovtek, JJ and tung-sol, no matter what, you can hear the tapping. The reason this is irritating me is whether I have it in the half power of full power, I'm getting a nasty hum out of the speakers. No matter what volume and no matter how far or close I am from the speaker cab. This happens with all of my speaker cabinets. All are 16ohm.

I've tried new Power tubes as well. New set of Mullards, new set of RFt's and JJ's. The hum sounds similar to the sound of blowing into a bottle. Any ideas? My honeymoon is quickly coming to end with this amp .

FleshOnGear
Rocker
Posts: 249
Joined: Thu Apr 09, 2015 9:33 pm
Location: Virginia
Contact:

Re: Nasty Hum out of JR Terror

Post by FleshOnGear » Sat Jun 20, 2015 12:52 am

Sorry you're having trouble.

Have you tried swapping any of the other preamp tubes? Does the humming stay the same volume no matter where the amp's volume control is set? Does the gain control affect the intensity of the humming? You say it sounds like blowing into a bottle. Is it a constant, sustained tone? Or, does it seem to rise and fall with your playing? If the amp itself is farther away from the cabinet, does that seem to lessen the humming? Does it really sound like 'ooooooooo,' or does it have any hint of a buzzing to it?

Just trying to get some more details...
Orange OR100
Marshall 2555SL
Freda 2x12's
Laney 2x12
Gibson Faded Flying V

Ronnie Robinson
Orange Master
Posts: 3148
Joined: Wed May 23, 2007 3:39 am
Location: In the beautyful North , UK
Contact:

Re: Nasty Hum out of JR Terror

Post by Ronnie Robinson » Sat Jun 20, 2015 7:25 am

Did you buy it new? Is it still under warranty?
Orange AD30 HTC
Orange Rocker 15 terror
Orange Tiny Terror HW,
Fender elite Start, Gibson SG 61,fender telecaster

Previously Owned - Rocker 30
Image

Hogie34
New Member
Posts: 13
Joined: Sat Apr 25, 2015 7:34 pm
Location: The High Desert

Re: Nasty Hum out of JR Terror

Post by Hogie34 » Sat Jun 20, 2015 10:12 pm

not under warranty any more unfortunately.

Yeah, I've tried replacing tubes in all positions. I mainly focused on that one at first cause it was the only position making noise when tapped on.

jontheid
Orange Expert
Posts: 821
Joined: Sun Nov 02, 2008 1:05 pm
Location: London, UK

Re: Nasty Hum out of JR Terror

Post by jontheid » Sat Jun 20, 2015 11:36 pm

All tubes are microphonic to a greater or lesser degree.
Higher gain amps are more sensitive to microphonic tubes - the higher the gain, the greater the amplification of everything - signal, noise, whatever.
Your problem does not sound like it stems from having a demonstrable degree of microphony from V1.
Microphonic tubes tend to add ringing noises during playing. When you have really microphonic tubes the amp can start to oscillate.

You describe the sound like 'blowing over a bottle' - this bring to my mind a noise profile with both high and low frequency components - a low frequency 'hum' which is probably 'mains hum' and a higher frequency 'shhh' time sound which may be more 'white noise' like, due to the high gain design with no noise gating.

Some folks have found that changing the fx loop tubes helps with nose on these amps, did you change these also?

FleshOnGear
Rocker
Posts: 249
Joined: Thu Apr 09, 2015 9:33 pm
Location: Virginia
Contact:

Re: Nasty Hum out of JR Terror

Post by FleshOnGear » Sun Jun 21, 2015 12:13 am

If you're getting a buzzing type sound, then it is likely power supply ripple, like jontheid says. The indicates either 1) you have a very badly balanced phase inverter tube, 2) very un-matched power tubes 3) a faulty preamp tube that is amplifying the heater AC, or 4) a serious power supply problem in the amp (bad capacitors, for instance). You say you've checked the tubes, and I can only assume that your power tubes are properly matched. If that's all good, you need to bring the amp to a tech.

If you are getting a smooth 'ooooooooo' type of sound, that means the amp is oscillating. This can on rare occasions be a tube issue (like a very badly balanced phase inverter tube, which affects the feedback around the power amp), but more likely means that something in the wiring of the amp is feeding back on itself and it needs the attention of an amp tech.

That's my take. Any other ideas, folks?
Orange OR100
Marshall 2555SL
Freda 2x12's
Laney 2x12
Gibson Faded Flying V

FleshOnGear
Rocker
Posts: 249
Joined: Thu Apr 09, 2015 9:33 pm
Location: Virginia
Contact:

Re: Nasty Hum out of JR Terror

Post by FleshOnGear » Sun Jun 21, 2015 12:20 am

You did try different guitars and different cables, right?
Orange OR100
Marshall 2555SL
Freda 2x12's
Laney 2x12
Gibson Faded Flying V

Hogie34
New Member
Posts: 13
Joined: Sat Apr 25, 2015 7:34 pm
Location: The High Desert

Re: Nasty Hum out of JR Terror

Post by Hogie34 » Sun Jun 21, 2015 12:46 am

I did try changing the cables. After changing the PI tube with one out of another amp ( just to see if maybe I had a hand full of less than quality tung-sol's) the hum went away. So, moral of this story, even if you have a brand new replacement tube for every position , they may all just suck! I hate current production tubes!!!

Just wanted to say thanks to all of you guys who chimed in with advice. I was at wits end going with normal tube roll/replacement and still having issues. Appreciate it all!

FleshOnGear
Rocker
Posts: 249
Joined: Thu Apr 09, 2015 9:33 pm
Location: Virginia
Contact:

Re: Nasty Hum out of JR Terror

Post by FleshOnGear » Sun Jun 21, 2015 1:18 am

Oh, yeah. I know what you mean. These days there's a difference between good tubes and new tubes. This past week I tested some brand-new tubes for a guy because one was red-plating immediately. He thought it was the amp's bias, but the tube failed the test - DOA. He had just bought it. Sometimes when you troubleshoot you need to have some known-to-be-good tubes laying around. Or, get the Orange tube tester :wink:
Orange OR100
Marshall 2555SL
Freda 2x12's
Laney 2x12
Gibson Faded Flying V

Post Reply

Who is online

Users browsing this forum: No registered users and 49 guests