Gibson Chet Atkins CE 1986 that hums!

[Scott Wackerman]

Hi,

 

I've checked all the solder connections and they are fine. It seems the pre-amp is compromised. The owner wants to keep the original volume and tone switch in the rotational orientation as from the factory. So far, most that I've spoken with resolve to change out the pre-amp, volume and tone parts. The problem is; the switches will not be in the same rotational orientation with the after market parts.

Any help would be most appreciated. If you are unclear about my problem then please review the photo's or get back to me.

 

Gibson_ChetAtkins_CE_1986_%20008.jpg

 

Gibson_ChetAtkins_CE_1986_%20013.jpg

 

Lastly, when I contacted Gibson, their solution would change out the original configuration! Arrrgh!

 

Regards, Scott 

 

[John Gummere]

Got it.  Sorry 'bout the florid language there, a little buzzed and missing my favorite axe.  I've got a rebuilt Ibanez strat-clone which is pretty nice too, but just not the same.

- JG

[Paul Verticchio]

@ Scott W:

Let me apologize for my oversight from a few months ago.  I should, at that time, have referred you to Kirk.

About 15 years ago, I was getting some supplies at a local "Luthier's Shoppe" in Springfield, IL.  Kirk dropped-in for a visit as Spfld is his hometown.  Anyway, the owner of the shop introduced me to his old friend Kirk as the guy that Gibson licensed the design from. Kirk eluded to the fact that most of his design work was not included in the final Gibson release.  I got the impression he wasn't too impressed with Gibson's model. Your story seems to confirm that.

Now that we know what seems to be causing the problem, it's obvious your customer is using the wrong tool for the job.  You've already put way too much time & effort into this attempted fix. Personally, I'd pass on the job if he continues to demand factory replacement parts. If they're not non-existent, they probably cost a small fortune... and all you'll get is the SAME poor design.  BTW: A nice A/E Flamenco can be had for way less than the cost of this repair. Plus, I can almost guarantee it'll sound 1200% better.  The bottom line: it's time for a new, updated & reliable instrument.

Which leads me to another thing we all need to think about, but not necessarily comment upon:.  With all the poorly made USA production instruments from the 80's & 90's and all the $100 specials coming from Asia arriving at our workbenches, we should all be thinking about where to draw the line.  I fear the glut of Asian instruments (AND there are some very good ones) will bury us all in non-cost effective repairs in the very near future. Our shop sends all the 'not worth the repair' instruments directly to the auction liquidators.  We've also been turning down more & more customers when the effort or cost "just ain't worth the time".

Best of luck with your "unreasonable customer expectations".  Have a great one (-:

[Scott Wackerman]

Hey Paul,

I had a detailed reply and somehow it was lost due to the internet phantoms. In summation; I assess the instrument. I give my opinion if the instrument is terminus or repairable. If terminus, I pass and explain why in exact terms which includes exorbitant costs and lengthy lead time. Second moral; have the person play the instrument as they would normally play so I understand their requirements in conjunction with the technique they employ.

I would have advised this customer to purchase a different instrument if I would have known that there were severe percussive expectations of this delicate instrument. No harm, no foul.

"Just ain't worth the time," is tenuous because we all place value individually but are constrained in any repair industry to "draw the line" because our time is finite and not infinite. ROI is real and we all have responsibilities. Temperance, moderation and patience is paramount in order to preserve ones sanity and business.

Cheers, S/

[Roy Martin German, Jr.]

I don't know if anyone from this topic is still around but I've got some interesting new information to share?

I've just purchased a 1987 SEC (the S is for second) Chet Atkins and it has the identical, combined piezo pickup and also lacks the separate leads and pots from multiple piezo pickups.

The new info is that this was also an official Gibson system made for them by Fishman ... because the piezo has the following writing impressed into it ... "Fisherman Transducer for CE and CEC".

Several things can cause the problems described in this thread, other than what's been discussed ...

Piezo pickups have to be properly setup to function correctly. When this guitar arrived, the bass strings were also far too booming and glitchy sounding. Bass frequencies travel omni directionally while treble frequencies are much more focused.

The piezo pickup is slightly shorter lengthwise than the slot so it could move about 3 mm and my first 'fix' was to center it and this immediately resulted in better treble volume level since the string now sat directly above the piezo crystal.

Also, the bone saddle was loose in the bridge slot causing imperfect contact with the piezo due to the lean of the saddle under string tension. A fast sanding to match the angle so that the base of the tilted saddle now sits flush on the piezo fixed the problem (now about 70% improved).

I do plan to replace this saddle with one that fits the bridge slot more accurately but they will always have some lean and it is a best practice to sand or file the base to counter act the lean such that the saddle has intimate contact with the piezo unit.

The wooden bridge was just starting to separate from the body (barely but a .005 feeler gauge found the problem). I suspect once I've removed it and removed the top clear coat which it was glued onto originally, that the remainder of the bass booming distortion (which is already 70% reduced) will diminished even more. 

Lastly, I will be changing the strings to high tension, titanium coated classical strings and I expect this to completely solve the sound issue.

The above will take me a few days so, I will let you know but already the sound has been greatly improved.

I'll also be contacting Fishman to see if they have further details on this design they made for these Gibsons?

BTW The guitar already sounds good and is extremely playable. I think the practice of finishing a guitar and then attaching the bridge to the finish, rather than wood to wood isn't a great idea? I also suspect that there are many more of these Gibsons made using the single pickup piezo unit that was manufactured with an imbedded label in it ... "Fisherman Transducer for CE and CEC". The engineer in me likes Chet's idea of individual string pickups but also understands that from a manufacturer's point of view, the single pickup solution should work nearly as well and be much simpler (read cheaper!) to produce and install.

[Scott Wackerman]

Hey Roy, 

I have found that aligning the "piezo crystal," to be a multi-iteration procedure. A balanced sound is dependent on the location. I would be interested in hearing what you yield from Fishman as I know first hand that Gibson was not interested in supporting this instrument due to obsolescence. My experience with this instrument lead me to a lot of dead ends. However over time I have found more information regarding parts and design of this instrument, i.e.,  Chet Atkin CE & CEC.  Let me know what you glean from Fishman. S/

[Roy Martin German, Jr.]

Hi Scott!

I'll be glad to keep you up to date on what I discover.

I don't make any money from my guitars so, I'm not time-constrained, which helps a lot.

So far, because the bridge needs to be removed and reset, I've only been using low tension nylon strings on this guitar. I'm dropping it off tomorrow (Friday) and expect to have it back from the luthier, next week.

But I've already discovered the piezo alignment issue you mention!

I find that the piezo moves about 1/8" either direction in the bridge slot.

On my new (eBay) guitar, the other issue was that the saddle didn't fit the wider slot properly so that it was tilted on it's bottom where it contacts the piezo. I filed it (very, very fine file) to a mirror finish with the base angled to sit on the piezo, properly. This greatly improved the sound the fisherman transducer produced!

Today, my order for a thicker saddle (3.2mm) arrived and all I needed to do was to shorten it to fit the bridge slot and it even sounds better than with the thin one. It took me 10 minutes to cut and fit it versus all day with the thin one to get it just right! But, I took it as a learning experience so, it was worth doing both of them, so that I could compare the results. The properly fitting one produces much nicer sound with better, cleaner over-tones that ring much more loudly on all strings than they did with the too thin bridge, even though it was filed to rest properly on the piezo. This is a very noticeable improvement in the sound!

Another problem with this bridge is that it is located just slightly too far towards the bass E so, if you center the piezo in the slot, the treble E string is extremely quiet. I've found that moving the piezo all the way until it hits the treble-E side of the slot works well for alignment of the crystals on my instrument.

Of course, since the bridge plate is lifting in the middle, it is also influencing the tone a lot. Especially loosing the higher frequencies. I'm hoping that the bridge reset and new, high tension strings will correct this? I'll let you know, next week.

So, until next week, fingers crossed! You never know how these things will turn out?

I have a Chet SST Epiphone steel string arriving on Saturday and I'm looking forward to spending time setting that one up while the other one gets repaired.