Zum Excessive Cabinet Drop?

[David Friedlander]

I’m the proud owner of an old Zum S10
I’m noticing quite a bit of cabinet drop. I play Day setup.
I press A and B when I tune my E’s
Once I release the pedal the E’s go a nice amount sharp. Seems to me, more than my ShowPro or Marlen.
The Zum weights a lot less than either wood guitar. Maybe the cabinet drop is related?

[Donny Hinson]

Exactly how much are the E's dropping?
Is it affecting your playing, or are you just worried about what the tuner is reading?

And why are you tuning your E's with pedals down?
I never understood why players do that, since the natural state of the open (E) tuning is pedals up.

[Tucker Jackson]

And why are you tuning your E's with pedals down?
I never understood why players do that, since the natural state of the open (E) tuning is pedals up.

Some players center the tuning at the pedals-down "A" note rather than at "E." There's no law that says it has to be centered at E... that's arbitrary, and there's a good reason to center at "A." I learned this from Ricky Davis, Larry Bell and others.

Following the procedure David described is one excellent way to adjust for the cabinet drop faltening that happens to the E string when you step on A and B. You're basically "tuning around." cabinet drop by following the procedure.

So, you put the pedals down. Cabinet drop lowers the pitch of the E string about 3 or 4 cents. You then tune the E string to +0 while that cabinet drop in play. This ensures that your E string will later be sitting where you want it when you play it against a pedals-down "A." Again, we've just declared that we're centering the tuning on the A note, so we need that E string to work with that when we step on the pedals and cabinet drop kicks in.

When you release the pedals, the E string pops back up by 3 or 4 cents (or whatever level the cabinet dropped it to before). You then tune the other strings in the open position against this slightly raised standard for the E note. You can tune by ear, or if you know the values of the cents involved and the targets you want to hit for your intervals, you can write a chart based on E being at +3, or whatever and work from there.

Once the open strings are in tune, you can then tune the pedals, ensuring that the B-pedal's "A" note comes in at +0. Boom, you've just tuned around cabinet drop: the open position is in tune with itself, and the pedals-down position is in tune and works... even though cabinet drop has lowered the E-string a little. That string will lower a few cents to be right in line with where you want it for the A chord.

The purpose of all this is to 1) adjust for cabinet drop and 'tune around it' so that it becomes a non-issue but also, 2) to do a better job of centering the overall tuning and it's various positions over the fret marker on the most common major chord positions:

The E chord will be slightly sharp at the nut (or fret marker) by 3 or 4 cents.
The A chord wil be in tune at the nut since, by definition, you've declared that's where you're centering the tuning at +0.
The A+F will (as always, in anything but Equal Temperment) be pretty flat at the nut. But you play that by positioning the bar significantly to the right of the fret marker. However, it's a little less to the right than if you had centered the tuning on E at +0. In that scenario, everything except the open E position is flat at the nut.

So some things are sharp of the fret line, others are flat, and this all requires slight bar manipulation... but the tuning as a whole is more centered over the fret line than if you use E at +0 to start the tuning process.

[David Friedlander]

Tucker summed my procedure up perfectly.
Seems to me, AB down is just about my main position.
I really need that C#-E ( strings 8 and 10) to be right on.
The old Zum is new to me.
It lived it's life as an Emmons and now, she's become a he ( hahaha) Jimmy Day.
The transition hasn't been all that easy.
I adore the guitar. It's just....wow.
Tone, and plays like Buttah
But I'm getting almost 8cents drop on string 8, about 5cent drop on string 4 when I hit A and B
Is his considered typical?

zum-under.JPEG

[Bobby Hearn]

My Zum was doing this but lowering the 7th string a bunch when pressing Pedals, I think there was a compensator causing an issue but I can’t remember exactly.

[Donny Hinson]

Actually, the guitar doesn't know if you're tuning the E pedals up or pedals down. As long as you tune the A&B pedals to match (sound good) with the open E, the end result is the same. My reasoning for tuning with pedals up is that adding the bar to the strings raises everything (due to bar pressure). And most of the time, we have the bar on the strings. So if you tune if you tune the E with pedals down and you have some drop, the E will go sharp when you release. Then, when you add the bar pressure, it gets even sharper. Of course, we do compensate with the bar to make everything blend well, but it always made more sense to me to have my high E match the guitar player's high E because any tuning irregularities between the lead and steel are more noticeable on the higher strings, and that's where we do the most playing.

As far as the 8 cents cabinet drop issue, that's a lot; and getting into the area of affecting playing. A skilled player can adjust the bar, as we always do, and still probably make it sound "okay". But that's not to say that some investigation into the source of that much drop isn't warranted. Make sure you're not pressing too hard on the pedals! Any added pressure (above that which is required to make the pedals hit the stop) will cause more drop because the pedal rods are pulling down on the cabinet; in effect, bowing it slightly. Loose changer or pillow block screws can also exacerbate the problem, as can loose end plate screws. (You should check all those areas on your guitar.) Most modern guitars have been engineered to minimize flex in the changer axle, but that can be an issue on a few guitars. Unfortunately, little can be done if it turns out that that's the cause.

Good luck finding the problem!

[Mike DiAlesandro]

I’m the proud owner of an old Zum S10
I’m noticing quite a bit of cabinet drop. I play Day setup.
I press A and B when I tune my E’s
Once I release the pedal the E’s go a nice amount sharp. Seems to me, more than my ShowPro or Marlen.
The Zum weights a lot less than either wood guitar. Maybe the cabinet drop is related?

Is this Zum new to you? Looks like the cabinet drop compensator rods that connect to the cross brace are missing? That's what the holes in the cross brace are for, seen many Zums that were set up this way. I would contact the seller and ask what happened to them, and why they were removed.

[David Friedlander]

Yes Mike. I just got the Zum. The seller isn’t cooperative which really sucks but hopefully I can find alternative assistance. Could compensator rods be fabricated?

[Mike DiAlesandro]

Yes Mike. I just got the Zum. The seller isn’t cooperative which really sucks but hopefully I can find alternative assistance. Could compensator rods be fabricated?

Yes, they can be easily made up, I believe Zumsteels use 7/64" pull rods, that just need threaded at 5-40, but don't quote me... The side that attaches to the center brace is a 90 degree bend, with an 1/8 collar, or cap nut, securing it.

Hopefully you purchased from a player and not a dealer, most dealers are more knowledgable and helpful...

Zum under cross brace.jpeg

[Doug Earnest]

First, do as Donny Hinson said and check every fastener including those on the round white nylon pedal stops on the front apron. It's an older guitar and could likely use a bit of preventive maintenance. Then do some exercises to see just exactly how much pressure you really need to get the pedals and levers to hit the stops. It probably never had any compensators. The braces were just made to accept them if desired.

[David Friedlander]

you guys......thank you so much!! I contacted the prior owner, who confirmed there were no compensators when he owned her.

Also- Speaking with Dave Grafe (another amazing dude)....he brought up the fact that you'd kind of have to compensate a lot...I see 5 compensator rods on the E10 side Mike's D10.

I'm going to check all the maintenance issues raised.
ANd the point about the ultimate compensator being our hand on the bar........maybe just deal with it as she is.
I really have fallen in love with tone and action....amazing.

[David Friedlander]

Yes Mike. I just got the Zum. The seller isn’t cooperative which really sucks but hopefully I can find alternative assistance. Could compensator rods be fabricated?

Yes, they can be easily made up, I believe Zumsteels use 7/64" pull rods, that just need threaded at 5-40, but don't quote me... The side that attaches to the center brace is a 90 degree bend, with an 1/8 collar, or cap nut, securing it.

Hopefully you purchased from a player and not a dealer, most dealers are more knowledgable and helpful...


Zum under cross brace.jpeg

Hi MIke,
Looking at yours a few things come to mind.
The crossbar on mine is flat- yours is curved to raise it up a bot....gives more room maybe? Also, my aprons are the same height; your front apron appears deeper than the back one. That could be the reason the crossbar is bent the way it is- maybe the whole setup is designed for the compensators
Second- looks like you have 5 compensator rods on your E9. That's what I mean when I said you have to compensate a lot.
How much drop are you getting when you press both pedals?

Also- the case looks great! Can I ask who made it?

[Mike DiAlesandro]

David,
The Zumsteel pictured was built for Larry Petree of Bakersfield, CA. He sold it to me and the comps were as he had them set. It is long gone, so no testing can be performed. I just used the photo to help clarify how Zumsteel steels were configured.

Doug Earnest built these w/Bruce, so he knows much more about this than I do...

Hopefully you will get this worked out and enjoy your new Zum.