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Topic: C pedal puzzle--PRP Mullen |
Brint Hannay
From:
Maryland, USA
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Posted 9 Aug 2020 2:25 pm |
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I changed the strings on the E9 neck of my '94 Mullen today--from SIT Buddy Emmons gauges to NYXL Medium--and now the C pedal is out of whack. I didn't change anything mechanically, just the strings. The new 4th string is a .015 instead of .014, but I can't see why that would cause this problem.
What's happening is, the 4th string lower finger is pulling along with the raise. This started as soon as I tried the pedals after tuning the open strings and before I touched the nylon tuner, and no adjustment of the nylon for the raise solves it (backing it off and starting from scratch, etc.). So it's impossible to tune the raise with the whole assembly unstable.
I notice a click when releasing the pedal that doesn't seem normal. It seems that I feel a "half-stop" in the pedal travel, possibly when the pedal picks up the 5th string raise, and it's at that point that the lower finger starts to pull.
Meanwhile, the raise on the F lever works normally.
The C pedal pull rod is not contacting the E lower pull rod or bell crank, and anyway, as I said, nothing was changed mechanically. I've peered into the changer and worked all the pedals and levers, and I'm pretty sure there isn't a ball end in the changer. If it were a changer lube issue, why would that appear abruptly after everything was normal before changing strings?
Anyone have ideas about what could be happening here? |
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Scott Swartz
From:
St. Louis, MO
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Posted 9 Aug 2020 3:25 pm
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Could it be a combination of more force to pull the .015 and not enough return spring tension?
From this thread
https://bb.steelguitarforum.com/viewtopic.php?t=296972
by Lane Gray:
The brain-bending bit is that, when you pull the raise scissor, the lowering scissor is held against the stop bar by the return spring, so pulling the raise scissor still invokes the pivot, but it still pulls it sharp.
Bruce showed it to me several times in his shop, but it never stayed with me until I rebuilt my first MSA.
I guess you would know if put a .014 back on and it started working, or you could tighten the return spring and try it.
_________________
Scott Swartz
Steeltronics - Steel Guitar Pickups
www.steeltronics.com |
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Brint Hannay
From:
Maryland, USA
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Posted 9 Aug 2020 4:00 pm
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Scott, I believe you hit the nail on the head. I tightened the return spring and now all seems well.
Thanks!  |
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Bobby D. Jones
From:
West Virginia, USA
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Posted 10 Aug 2020 8:25 pm
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When that 1 thousandth between 14 and 15 thousands string is calculated, It figures out that there is 6.666 % difference in the string area, which would make it react different in raises or lowers. This Would be the reason you had to change spring tension to get the guitar to tune properly.
If you go from a plain 6th string to a wound or vice versa can cause another tuning problem. |
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Tony Prior
From:
Charlotte NC
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Posted 11 Aug 2020 12:58 am
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remember when we were all asleep during PHYSICS class ? This is what they were talking about ! 
The 4th string , C Pedal, on our Instrument will rear its ugly head first with this physics thing. Glad you got it worked out.
_________________
Emmons L-II , Fender Telecasters, B-Benders , Eastman Mandolin ,
Pro Tools 12 on WIN 7 !
jobless- but not homeless- now retired 9 years
CURRENT MUSIC TRACKS AT > https://tprior2241.wixsite.com/website |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 11 Aug 2020 3:46 am
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| Bobby D. Jones wrote: |
| When that 1 thousandth between 14 and 15 thousands string is calculated, It figures out that there is 6.666 % difference in the string area, which would make it react different in raises or lowers... |
Actually, it's the diameter différence that's 6.666%, whereas the cross-sectional area difference is 8.711% |
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