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Topic: Ghost tones in a tube amp? |
Gary Cosden
From:
Florida, USA
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Posted 2 Mar 2014 8:44 am |
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| I have a 67 Dual Showman head that was gone through by Ken Fox about 5 years ago. Just recently I am getting pretty nasty ghost or difference tones and it's worse the farther up the neck I play. I typically use the Number 2 input and I have tried it without pedals or volume pedal and it's pretty much the same even at low volumes. I'm hearing a fair bit more distortion whenever I play more than 1 note at a time as well. Just now I checked the pre amp tubes and it seems to me that number 1 MIGHT be a tad microphonic as I hear a very feint tone that lasts a second or so when I tap on it. Any ideas? I don't see it being caps after 5 years but I know just enough to set the house on fire when it comes to vintage tube amps. |
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Tim Marcus
From:
San Francisco, CA
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Posted 2 Mar 2014 8:48 am
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Sometimes the phase inverter does that when something drifts way out of tolerance, or a bad output tube
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Milkmansound.com |
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Gary Cosden
From:
Florida, USA
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Posted 2 Mar 2014 9:34 am
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| Think I should try a new tube for the phase inverter? |
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Tim Marcus
From:
San Francisco, CA
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Posted 2 Mar 2014 10:18 am
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wouldn't hurt to try
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Milkmansound.com |
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Jeff Porter
From:
Stumptown, OR, USA
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Posted 2 Mar 2014 12:41 pm
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There are some good threads about ghost note diagnosing at the amp garage site (ampgarage.com).
Also Gerald Weber (Kendrick Amps) has some good stuff in his tube amp books about testing and resolving different tube amp problems. If you mess around with your own amps much it's worth picking up his Tube Amp Essentials book.
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"I make dozens of dollars a year playing music." |
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Bill Duncan
From:
Lenoir, North Carolina, USA
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Posted 4 Mar 2014 6:33 am
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I also get some ghost tones with my tube amp. The tones I get are most prevalent when I ride strings 3 & 4 together, especially when picked and allowed to ring over several bar moves. The higher up the neck I go the more I notice them. It only started recently, and I have a feeling I have a tube problem.
Some of the quirks of tube amps I guess. Although I have noticed a little of that with my solid state amps, but barely noticeable.
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You can observe a lot just by looking |
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Stephen Cowell
From:
Round Rock, Texas, USA
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Posted 4 Mar 2014 6:52 am
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Any noise that lasts as long as a second is not good... you can try swapping out or subbing V1 and see. Also, if you're only using channel 2, you can pull V1 completely... it's only used for channel 1. This is a trick to get a little more headroom from a Fender amp... the preamp supply goes up a few volts when the tube's not in circuit.
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Too much junk to list... always getting more. |
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Gary Cosden
From:
Florida, USA
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Posted 4 Mar 2014 5:09 pm
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| I will try swapping out V1 Stephen - good tip. Just now I was playing and I noticed that while at the 13th fret playing strings 3 and 4 with pedals B&C down the ghost note I got was Bb that would RAISE an octave as I rocked off the pedal! In other words I'm playing Bb and D and the ghost note is Bb an octave lower. When I rock off the C pedal lowering the D note to C the ghost note Bb raises a complete octave! I have no idea what this means but I find it interesting. It must have a specific cause. |
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Bill Duncan
From:
Lenoir, North Carolina, USA
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Posted 5 Mar 2014 4:30 am
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I get the same thing Gary. It is much worse if the reverb is up. It is probably the same, but a lot of reverb seems to make it more noticeable.
_________________
You can observe a lot just by looking |
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Lane Gray
From:
Topeka, KS
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Posted 5 Mar 2014 6:04 am
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Gary, that's the nature of IM distortion. It has a correlation to the mathematical relation between the 2 notes getting to the amp. It will always try to make a major chord: if you feed it E and B, it'll give you a G#, if you move the B to A, it'll swoop to C#, but if you move the B to C, you'll hear it move to G (but I think it moves nearly an octave instead of a semitone).
If I'm in the mood to tune by ear and be dead on, I'll crank up the fuzz box and let the IM get it dead on.
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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Tim Marcus
From:
San Francisco, CA
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Posted 5 Mar 2014 8:11 am
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This is part of the "mojo" of tube amps. Without it, amps sound kind of lifeless. It'll be there in the background at all times - and might be annoying when you play alone - but in a group or on a recording it usually gets swallowed up and becomes part of the vibe
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Milkmansound.com |
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Paul Arntson
From:
Washington, USA
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Posted 5 Mar 2014 9:47 am
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| Lloyd Green's tone on Live at Panther Hall? |
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Mark Draycott R.I.P.
From:
Portland, OR
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Posted 5 Mar 2014 4:31 pm
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The last amp I fought with for ghost notes, turned out to be a bad filter cap. It could be a bad capacitor in the power supply section.
Mark
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1976 Sho-Bud Pro II, 1976 Sho-Bud LDG, BF Fender Deluxe, Evans FET 500 LV, BF Princeton Reverb, '68 Vibrolux Reverb |
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Bill Hatcher
From:
Atlanta Ga. USA
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Posted 5 Mar 2014 7:36 pm
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| second the filter caps. especially if low sub ghost tones. |
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Gary Cosden
From:
Florida, USA
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Posted 9 Mar 2014 6:42 am
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I finally got the chance to work on this some (My Mother in law is visiting all week!) and here is what I found:
1) Pulled V1 and no luck. In fact the power was down to almost zero.
2) Tried every combination of 12ax7 I've got in V2 and V3 and still no luck.
3) Swapped out V4 with a nos Mullard and now I've got full power back and to my ear a real improvement in tone as well. IM distortion is back where it belongs (wherever that is)
I really like to use both channels so I think I'll order a new set of 12ax7's from Ruby Tubes.
Thanks to everyone who took the time to chime in with your thoughts. |
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Tommy Hannum
From:
Tennessee, USA
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Posted 12 Mar 2014 11:34 am Ghost tones in a tube amp?
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It's possible that your amp is fine, and you are hearing what is called a "difference tone". This may be similar to what Lane posted.
When you play two notes, a third note is produced whose frequency is the difference between the 2 you played. This 3rd tone is more noticeable as you play way up the neck, as the low difference tone comes into hearing range. Try playing 3 and 5 at 17th fret, then press 1st pedal, you will hear a low note move with (or against) the pedal...ususally out of tune with what you are playing .
Some amps, and some tone settings can accentuate this.
Tommy Hannum |
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Bill Duncan
From:
Lenoir, North Carolina, USA
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Posted 12 Mar 2014 2:05 pm
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My ghost tones are "friendly ghosts".
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You can observe a lot just by looking |
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Mike Schwartzman
From:
Maryland, USA
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Posted 12 Mar 2014 2:30 pm
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2 weeks ago , I was playing bass through a Blackface Showman. The first tune contained a C chord, so naturally I played a C note and the amp went Buzzzzz.
Every C note from highest to lowest C on the entire bass neck made the same buzz. No other note did that. Short story... it was a dirty tube socket on one of the 2 preamp tubes. Glad it was rehearsal.
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Emmons Push Pull, BMI, Session 400, Home of the Slimcaster Tele. |
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