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Topic: Harmonic Distortion. |
Lawrie Minson
From:
New South Wales, Australia
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Posted 2 Sep 2016 4:37 pm |
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Hi, I've been playing PSG for many years and have used Bill Lawrence blade PUs, a George L Emmons 66 and I recently purchased a 12 string MSA Legend from Jim Palenscar that has a Tonealigner humbucker.
I started looking through the many posts trying to find some info on harmonic distortion but I thought it might be quicker to ask the question - It seems to me that a common problem with humbucking pickups for steel steel guitar is low harmonic distortion created when two or more strings are played together. It's been years since I used a single coil pickup so I don't know if the problem is the same.
You can hear the distortion when the steel is plugged directly into an amp and is worse when effects are added. I've tried a number of tube amps on both the high and low impedance inputs.
I know that low harmonics are created when two notes are combined but I was wondering if anyone else has experienced this problem and found a solution. I'm trying to do some recording and it's driving me nuts!
Thanks, Lawrie Minson - Tamworth Australia |
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Lane Gray
From:
Topeka, KS
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Posted 2 Sep 2016 5:46 pm
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I've found it lessens considerably if you increase the distance between string and pickup.
I find tone improves as well. Instead of 3.5mm, I like 5-6
_________________
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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Brad Sarno
From:
St. Louis, MO USA
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Posted 2 Sep 2016 6:12 pm
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And also, while steel pickups are very high output and can easily overdrive the inputs to some amps when plugged in directly, typically we place a volume pedal between the pickup and the amp and tend to operate at well below half of the full signal voltage coming from the pickup. I find that even a fairly sensitive input on a Fender tube amp can handle a typical, post-volume-pedal signal level very cleanly. Sure, there's gonna be more of this subtle harmonic distortion in a tube amp than in a transistor amp, but under normal conditions this is not a problem. We have decades of legendary pedal steel recordings all played thru tube amps. And while modern pickups may be hotter, higher output, we still compensate for the level with our volume pedal and settings.
But I agree, if you plug a steel guitar directly into an amp, it can likely overload the input in many cases.
Brad |
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Lane Gray
From:
Topeka, KS
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Posted 2 Sep 2016 6:15 pm
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And if you have a "heavy" right hand, we can push some crazy transients even through the volume pedal.
_________________
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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Brendan Mitchell
From:
Melbourne Australia
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Posted 3 Sep 2016 2:56 am
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| Don't know if this belongs in this discussion but I was having trouble at a show last night when I was getting some of that high pitched screaming distortion . An ETS with a GeaorgeL pup through a Bandmaster with the volume set on about 4 . This would only occur with the volume pedal fully open . This was with a fairly loud band and it was driving me nuts , the guitar player suggested my pup had gone michrphonic , is that possible ? Any other suggestions ? And is that pup humbucking or single coil ? |
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Jon Light
From:
Saugerties, NY
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Posted 3 Sep 2016 3:26 am
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| @ Brendan--I once had an out of control feedback problem and discovered that my reverb tank had become unfastened from the cabinet and was magnetically attached to the speaker. If that sounds like it can't be conducive to good sound, I can assert that it was not conducive to good sound. |
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Bob Hoffnar
From:
Austin, Tx
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Posted 3 Sep 2016 7:32 am
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What amp are you using ?
BTW: the original pickups on my 64 Emmons do it to. It is a natural part of good tone. Unless something is drastically wrong.
_________________
Bob |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 3 Sep 2016 9:30 am
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Sounds like you're over-driving. Turn the amp master volume all the way up. That forces you to use less volume pedal, which, in turn, reduces the signal you're putting into the amp. This will reduce all distortion. 
Lowering the pickup may help too, but many guitars won't let you lower it enough to correct the problem. |
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Brian Evans
From:
Nova Scotia, Canada
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Posted 3 Sep 2016 11:28 am
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| With a Bandmaster (at least my 1968 BM) it's very easy to overdrive the first pre-amp stage - it's direct in. Use the low sensitivity input, turn the volume down on the guitar and turn the volume on the amp up high. That lets the second pre-amp stage do more of the work. |
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Bob Hoffnar
From:
Austin, Tx
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Posted 3 Sep 2016 2:02 pm
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I've worked on this specific issue quite a bit. shoot me a note and we can do a Skype thing and figure it out.
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Bob |
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Lawrie Minson
From:
New South Wales, Australia
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Posted 3 Sep 2016 6:59 pm Thanks for the tips..
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Thanks for the advice everyone. I'll have a look at the MSA and see if I can get the pickup any lower. I plugged in my old 10 string JEM (made by my Dad, John Minson)to do a comparison. It has a George L E66 pickup which is brighter than the Tonealigner. It occurred to me that a fatter pickup (more mids) will tend to accentuate the harmonic distortion. This seems to be the case. I can still hear a bit of the same distortion on the E66 but it's nowhere near as noticeable. I do have both pickups fairly close to the strings so I'll try lower the PUs on both instruments and I'll let you know how I get on.
BTW - another cause of high pitched feedback can be a microphonic tube (if you're using a tube amp, of course..)
Cheers, Lawrie |
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Brendan Mitchell
From:
Melbourne Australia
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Posted 4 Sep 2016 1:59 am
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| Hi Laurie , I didn't realise this was your post ! |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 4 Sep 2016 7:17 am
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| Donny Hinson wrote: |
| Sounds like you're over-driving. Turn the amp master volume all the way up. That forces you to use less volume pedal, which, in turn, reduces the signal you're putting into the amp. This will reduce all distortion. .... |
What Donny said!
Turning the amp UP will make your right foot play quieter on the volume pedal, and that quieter level coming from the volume pedal should come way down enough to NOT distort your input or preamp stages. I play thru Fender amps all the time and have no issue with this kind of distortion unless my volume pedal is too high.
B |
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Lawrie Minson
From:
New South Wales, Australia
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Posted 4 Sep 2016 10:24 pm Slight improvement
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| Hi, I've lowered the pickup (as suggested by Lane) and it has helped reduce the problem. I should also clarify something - I'm not talking about distortion from an overdriven preamp. When two notes of a chord are played together they produce a low fundamental harmonic that is usually the root note of the chord regardless of which two chord notes are combined. This fundamental harmonic is usually an octave lower and THIS is the thing that I'm finding unpleasant because unless the two notes are in perfect harmony the fundamental low overtone will be either flat or sharp. I think the extra mids from my pickup are exacerbating the issue. I'm also getting about 6 cents cabinet drop which (at the moment)is making it extremely difficult to keep everything sweet. Hence the sharp/flat overtone issue. |
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Lane Gray
From:
Topeka, KS
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Posted 5 Sep 2016 5:11 am
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It's called "intermodulation distortion", and it IS an artifact of other distortions. Pure sine waves don't do this (or at least at audible levels), so if you're hearing IM, your single notes aren't as clear as you thought.
_________________
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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Bob Hoffnar
From:
Austin, Tx
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Posted 5 Sep 2016 9:18 am
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I would be careful with obsessing about the IM issue. It is a necessary part of good tone. Like the slightly bitter taste in chocolate. You can get rid of it but you may lose more than you gain. I hear it in almost all great steel guitar recordings.
To change your volume pedal technique like the suggestion of Brad and Donny could potentially cause more problems than it will solve.
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Bob |
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Bob Hoffnar
From:
Austin, Tx
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Posted 8 Sep 2016 5:51 am
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I probably made that tonealigner. Some people requested pickups with more resistance tan others. Let me know if it is a 12 or 10string and what the resistance is. It might be the pickup.
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Bob |
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Lawrie Minson
From:
New South Wales, Australia
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Posted 8 Sep 2016 4:14 pm Tonealigner
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Hi Bob, the MSA Legend is a 12 string and the DC resistance of the Tonealigner is 22.4k.
I was using a Beyer M88 dynamic mic (amp has 2 x 12" speakers)and added a Rode NT2 condenser to the other speaker and that helped things considerably. I have finished the project and I'm now ready to tackle the MSA as I have some more studio work at the end of the month.
Thanks to Lane for the terminology - Intermodulation Distortion is the enemy!
Cheers,
Lawrie |
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Bob Hoffnar
From:
Austin, Tx
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Posted 8 Sep 2016 8:02 pm
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Hmmm.... That is pretty normal for a 12st pickup. The problem with trying out different pickups with the new MSAs is that it is crazy expensive.
When I had an issue with IM I used a Goodrich matchbox with a volume control in between the guitar and volume pedal. Seemed to help.
Is the amp on the floor or in a corner ? Have you tried a good ribbon mic or a plain old shure 57 ? Where do you place the mic ?
It might be something like that if you don't have a problem when you play live.
_________________
Bob |
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Lawrie Minson
From:
New South Wales, Australia
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Posted 10 Sep 2016 12:23 am IM distortion
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Hi Bob, you're right, the choice of mics made a difference. When I added the Rode NT2 things improved immediately plus I went back to using my Dad's steel with the E66 pickup, a brighter tone and less mids. The amp was on the floor in a carpeted room and I had the mics placed about a foot away from each of the 12" speakers. I haven't noticed the problem live but I've only recently purchased the MSA and have only done a handful of gigs with it.
I think the big issue at present is the cabinet drop and I will look elsewhere in the forum posts on that one. I'm sure there are pages upon pages.
Thanks for taking an interest and your helpful tips.
Cheers,
Lawrie |
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