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Topic: Tuneable split on Zum U12? |
Ad Kersten
From: Beek en Donk, The Netherlands
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Posted 6 Feb 2004 4:08 pm
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I can raise the 5th string (B) a whole tone to C# with pedal 7 and lower it half a tone to Bb with right knee lever up.
Both P7 and RKU are in tune if used seperately but the note I get using both at the same time is not a C: it is too high.
Can somebody tell me how I can tune the C note if I use p7 AND RKU at the same time.
Can I do this with compensators or return springs?
Ad
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Zumsteel S12U
Yo, Man! homepage
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C Dixon
From: Duluth, GA USA
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Posted 6 Feb 2004 4:28 pm
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There are two ways to obtain a "tunable split" on a PSG:
1. Allen set screw on top of the guitar; to the right of the changer.
2. Using an additional raise rod on the lower bellcrank.
Since I do not know if Zum uses the allen screw method, I will describe the "extra raise rod" method; which can be done on any steel except the P/P.
1. Install an additional raise rod on the B to Bb lower bell crank.
2. Run this rod thru a raise hole in the changer on string 5.
3. Thread on a nylon tuner on this additional raise rod.
To tune, do the following:
1. Engage both changes to engage the "spli" and tune the split note With the tuner that you normally used to tune the Bb note.
2. Engage the B to Bb change and tune the Bb note with the new extra raise rod tuner.
NOTE: if the Bb note ends up too sharp after you tune the split, there is no cure for this that I know of. This happens to me because I tune my C#'s so flat that the split adjustment leaves the Bb too sharp. As such the extra raise rod is of no use; since it is only used to raise--never lower.
carl |
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Patrick Ickes
From: Upper Lake, CA USA
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Posted 6 Feb 2004 8:44 pm
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My Zum uses the set screw method Carl refers to. I'll quote from my owners manual:
"TUNING GUITARS EQUIPPED WITH SPLIT-TONE OPTION
The tuning proceedure is as follows:
1. Tune open tuning with the keys as usual.
2. Tune raises with the nylon nuts as usual.
3. When both the raise and lower funtion are engaged at the same time, the resultant note is tuned with the nylon nut that lowers the string. Turn clockwise to flatten the note.
4. Finally, tune the lowered note alone with the set screw in the end of the neck, immediately behind changer."
If yours doesn't have the set screws installed, look for holes in the end of the changer that would take an 8x32 screw. If yours is older, it may not be possible to split tone.
Hope this helps,
Pat |
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richard burton
From: Britain
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Posted 7 Feb 2004 2:06 am
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Carl,
One problem I have noticed when using the extra rod for splitting is that the sequence of operating pedals and levers produces slightly different notes, ie if the guitar is tuned for an accurate split by pressing pedal A then moving LKV, if the sequence is reversed (move LKV then press pedal A), the note won't be true. I don't know if this is usual, but I have noticed it on several steels.
R B . |
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Bobby Snell
From: Austin, Texas
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Posted 7 Feb 2004 7:55 am
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Bill Rudolph told me that only one change (sharp or flat) is tunable on a split. On my Williams D10 I tune the 5/10 strings to tune accurately going from C#-C, and the 6 string going from A-G. This because I find it easier to pedal up halfway on the first pedal, e.g. for an aug 5th rather than finding the major third to minor third with both pedals down and trying to half-pedal down. The A-G on the 6th string is more valuable to me as the dom7 than finding the minor third up from the 2nd with the lever and pedal as a motion. YMMV with a SU12. |
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C Dixon
From: Duluth, GA USA
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Posted 7 Feb 2004 8:09 am
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Richard,
What you are describing is a phenomenon on most PSG's when "splitting". It is called hysterisis; and was first identified and accurately written up 30+ yrs ago by Tom Bradshaw. Albeit, Tom wrote about it from a different point of view, but the two problems are caused by the same phenomena.
When a string is lowered and then raised, the string will not be at the same pitch as it is when raised then lowered. The cause is not in the cabinet, changer, pullrods, stops etc. Rather, it is at the key head where the string length between the nut rollers and the key post is not coming back at rest at the same point going one way as the opposite way.
Where this problem is most evident on keyed guitars, is string 4 with the use of the E* and F knee levers. IE, when you raise the string and return, it comes back to E. Then when you lower it and return, it comes back sligtly sharp. Or vice versa depending on which you tuned first.
Detailed study and one discovers that all of the string that goes over the roller on a lower, does NOT come back when the lower is released. Oiling the rollers I have found has little, if any affect. It is just the nature of the beast.
Keyless guitars almost eliminate the problem. In most cases, they are about 95% effective in curing the problem altogether. In fact one of the PRMIE reasons for going to a keyless is to overcome hysterisis. Sadly, keyless guitars rarely satisfy players who are used to the richer overtones emitted by a keyed guitar.
* (NOTE: some refer to the E lever as the D lever-wrongly IMO)
May Jesus richly bless you all,
carl |
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Ad Kersten
From: Beek en Donk, The Netherlands
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Posted 7 Feb 2004 12:50 pm
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Thanks guys!
I just checked my Zum but it does not have the allen screws behind the changer. I understand how it operates though. My zum is about 15 years old; maybe Bruce did not add split tunings at that time.
I also do not have any room left for an extra pull rod. Since it's a universal, I use all the three raises available. Pity it would have worked .
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Zumsteel S12U
Yo, Man! homepage
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