Edwin Wilson on reissue Bumble Bees

Regarding a letter from Edwin Wilson the program manager of the Custom, Art & Historic Division at Gibson
which was posted at www.gibsoncustom.com/bumblebee/index.htm in late 2004.

While this letter is long-gone from Gibson's website, it is saved here with some additional information from
the Les Paul Forum and Wesco, the company that manufactures the reissued capacitors.

 


 

I am writing this in response to some concerns on both the UNOFFICIAL LES PAUL FORUM and the Gibson Custom Shop Forum about our Bumble Bee capacitors and their authenticity, construction, specifications and the approach to reissuing any hardware on Gibson Historic Products.

First of all, to all those that are experts regarding capacitors just work through the first part of this with me because there are so many people that I have heard toss around descriptions like ceramic, oil filled, foil, mylar,teflon, and paper I feel a little general information is necessary to clarify. The actual definition of a capacitor is: An electronic circuit element used to store charge temporarily, consisting in general of two metallic plates separated by a dielectric. One of the main differences between the various styles of capacitors is the dielectric medium used. In a ceramic capacitor the dielectric is ceramic. The parts used in this style of capacitor consist of the metal plates which have the solder leads attached to them and the dielectric which is ceramic. This is also the most inexpensive capacitor available with the poorest ability to hold a charge. The next one is a mylar capacitor. With this one, it also consists of two metal plates which are the points that you solder and the dielectric which in this case is mylar. The capacitor with the highest quality material and performance is a teflon capacitor.


Reissue bumblebee leads

Typically this style is used in higher end custom audio applications where exacting tolerances are necessary. If you go back to the days of antique radios, you will notice some of the first capacitors were oil filled capacitors. With this style capacitor it consists of two conductors which are the metal plates and the dielectric material which is oil. Typically these parts had a metal can around them so that the oil would be contained. There were many materials used as the dielectric material including paper and foil. As many of you know also on any old electronic part the variations in different tolerances were much greater than now. What was considered a high quality part in the 40's and 50's was a variation of +/- 20%. By today's standard that is totally unacceptable. Once again the bottom line is the metal plates generate a charge when a signal is sent into them and the dielectric material holds the charge and releases it on a constant. So with all of that said let me get into how this project was approached.

So many times when I R & D parts or models for reissues I get assistance both positively and negatively from many sources and all input is appreciated. But in addition to this input I also have access to a vast amount of engineering documents,blueprints, and purchasing records dating back to the '40s, '50s, '60s etc. So many times when it appears that someone at Gibson has not reissued a part or a guitar to a particular individual's idea of what it should be, the closest most realistic information from a manufacturing standpoint is the documentation that we used to make the parts/guitars originally (even though sometimes there are variations between what the blueprint says and what the part ends up looking like).


Reissue BumbleBee foil

When I started this project I contacted Sprague (the original manufacturer of Bumble bee capacitors), and got as much information from them as I could. Next I went to our purchasing records and searched until I found the vendors that were the distributors and actually sold Gibson the parts. On these documents I found not only the vendors names but also the exact description of the parts and the specifications. Next I went to see if there were any blueprints but I did not have much luck there. Oh one other thing I forgot to mention one of the things I keep in my possession here at the Custom Shop are many original pickup, control assembly, and pickguard sample parts from as far back as the 40's including an original Double 12 wiring harness dated on March 1958 on the inventory/tracking tag.

So once I found a vendor* willing to listen to my request I sent him 5 original Bumblebee capacitors to run tests on with the specifications from my purchasing records. Once he ran the tests he informed me that to a degree there was a varied range of the voltage and capacitance. Two of the capacitors read exceptionally high indicating some kind of breakdown within the dielectric material (foil).
*WESCO

Three of the capacitors were right on with what I had found in our records and with what the capacitor was supposed to be spec wise according to the color bands on both the original and the new. It was very easy to see but we still ran the test to make sure the color bands were actually what the part was. For those of you who do not know how to read the color bands on a capacitor, (it is different than a resistor), I have attached a sheet explaining. Next I discussed the actual construction, material and dimensions. I wanted the wire size on the leads, shape, color bands, tooling marks,color and all to be as close as possible but most importantly it had to be a foil capacitor with a dielectric at least comparable to the original brown craft paper and the specifications had to match the original bumble bees. On the reissue bumble bees the dielectric material we ended up going with was a poly film that exhibited the same properties as the craft paper did. This decision was made based on numbers and manufacturing issues. It is simple math, if one material conducts at a certain rate then if you find another comparable material and make the necessary adjustments be it in size, thickness, or turns the you end up with the same desired result. On the first samples they sent me they were plain without the shell just the foil and leads showing so that I could approve the construction. Next came the outside shell with the color bands and tool marks. Finally came the finished part.


Original bumblebee foil

I did not take these and x-ray them but as with all good R&D'd projects, there are sacrifices. So attached I have put some of the tech sheets from my vendor for you to read over, along with some detailed pictures and my measurements I took of an original bumble bee I took apart and some other ones of a recent new reissue bumble bee's so that everyone is very clear that this is not a ceramic capacitor in a nice package but truly a foil capacitor, like the original bumble bees, in an injection molded case, like the original bumble bees.

Earlier on in this I said I appreciate all input and I do; it helps all of us at Gibson make better decisions about the product. But I still find it amazing that some people still think that someone is out to get them. I remember '80s Les Pauls that were not even the right shape, had the wrong necks, peghead shapes, routes, made from African Mahogany not even the same species, wrong binding size, wrong hardware and at that time this is what the company offered as a reissue style guitar! Yet now in 2003 when we go through the greatest lengths to make the guitars correct, when we use the highest quality materials ever in the company's history, the body shapes, necks, pegheads, neck tenons, pickups, pots, capacitors, and aluminum stopbars are more accurate and close to an original that ever, there are still individuals that feel we are out to pull one over on them. The things I mentioned above are the most important elements in any guitars sound and playability, except for one thing I left out..... the guy playing it.


Original BumbleBee leads

Our intent with the bumble bee capacitor was to make a reissue capacitor as authentic as possible using the same basic elements that the original ones used, with the same specifications and performance, to make a part that in 20 or 30 years was still going to perform as well then as it did new, to improve the quality of sound of the guitars and be another contributing factor in making these guitars one step closer in sound and playability to an original, And the greatest guitars that anyone could ever own. And we feel very strongly as do many others that we have accomplished this. If there are any further questions about this or any other parts/guitar issues, before any wrong assumptions are made, please feel free to get in contact with me directly at ewilson@gibson.com, or use the Historic Program Discussion Forum found at http://www.gibsoncustom.com/.

 

HOW TO READ CAPACITOR VALUES

 

 

WARNING FROM THE MANUFACTURER THAT FURTHER TESTING MAY DAMAGE CAPACITORS

 

 

MANUFACTURER'S SPEC SHEET SHOWING REISSUE CAPS MEETING GIBSON SPECS

(note the variance of tolerance from .0198uF - .0242uF)


BUMBLEBEE CAPACITOR COMPARISON:

ORIGINAL BUMBLEBEES

Lead Size: .025" to .035"
Foil Dimensions: height .890" tall, .0005" thick
Paper: Thin, brown craft paper; height .900", thickness .001"
Layers: foil/paper/foil/paper (4-ply)
Ends: lead based metal, 60/40 lead/tin

2003 BUMBLEBEES

Lead Size: .025"
Foil Dimensions: height .650" tall, .0015" thick
Poly (separator/dialectric): height .750" tall, .0015" thick
Layers: foil/poly/foil/poly (4-ply)
Ends: lead based


Edwin Wilson
Historic Program Manager
Gibson Custom, Art & Historic Division


 

Disecting a Reissue Capacitor ...Surprise!

 

Wesco Capacitors

Pictures of a disected Gibson re-issue Bumblebee capacitor, posted 01-28-05 on the Les Paul Forum
courtesy of pepejara:

and here the markings can clearly be seen: WESCO  32PL  223J

unrolled:

is this the same capacitor as in Edwins picture? hmmm:

 

The following is the actual spec sheet from WESCO for these 32PL 223J capacitors:

 

    Type 32PL



&nbsp


SPECIFICATIONS



DIELECTRIC WITHSTANDING VOLTAGE

200% of rated voltage applied through a minimum limiting resistance of 100 Ohms/Volt. Duration of voltage stress shall be 15 seconds minimum and 1 minute maximum at 25°C.




INSULATION RESISTANCE

At 25°C after 2 minutes of electrification at rated voltage or 500 VDC, whichever is less, the minimum product of Insulation Resistance and Capacitance shall be 250,000 megohms-microfarads, but need not exceed 250,000 megohms.




DISSIPATION FACTOR

Shall not exceed .05% when measured at 25°C and 1000 Hz, ±20 Hz. See characteristic curves for D.F. ratings at other temperatures.




CAPACITANCE AND TOLERANCE

Shall be measured within the tolerance limits specified. Measurements will be made at 25°C and 1000 Hz, ±20 Hz.




LIFE TEST

Shall withstand 140% of rated voltage at 105°C for 250 hours. One failure in twelve shall be permitted.




TEMPERATURE COEFFICIENT

Capacitance shall change linearly over operating temperature range range of -55°C to +85°C at rate of -290, ±75 parts per million/°C.




CAPACITANCE STABILITY (DRIFT)

Less than .2% when measured in the following manner: three capacitance readings at 25°C, each made prior to and after temperature cycling from room to 105°C, and room to -55°C. The mathematical difference between the two extremes, divided by the intermediate value, and then multiplied by 100, yields the stability expressed in percent.

 

FEATURES

  • Wrap and fill construction

  • Excellent long-term stability

  • Superior "Q" for tuned circuits

  • High insulation resistance

  • Linear temperature coefficient (-55°C to +85°C)

  • Quality control procedures per Mil-Q-9858

  • Extended foil design



APPLICATIONS

  • Computers

  • Data Processing Equipment

  • Aircraft and Missile Systems

  • Industrial Instrumentation

  • Navigation and Distance Measuring Equipment

  • Communications Equipment

  • Timing and Retrace Circuits

  • Integrating Networks

  • High "Q" Low Loss Filters

  • Peripheral Equipment





HUMIDITY RESISTANCE

Meets requirements of Mil-C-27287, Para. 3.12 when tested in accordance with Mil-STD.-202, Method 103 B, Condition B.



LEAD PULL AND BEND TEST

Steady pull of 5 pounds applied axially to leads for one minute. Bend test shall consist of one bend from the point of egress, first 90° in one direction, back to the original axial position, and then 90° in the opposite direction with no evidence of breakage.



TEMPERATURE RANGE

-55°C to +105°C with full rated voltage applied.


3a.GIF 4a.GIF
32PL
RATINGS and DIMENSIONS


TEMPERATURE
CHARACTERISTIC
CURVES

CAPACITY
IN MFDS.
100 VOLTS
D L CAT. No.
32PL----K-1
200 VOLTS
D L CAT. No.
32PL----K-2
400 VOLTS
D L CAT. No.
32PL----K-4
  .0010
.0015
.0022

.0033
.0039

.0047
.0056
.0068
.0082
.0100

.015
.022
.027
.033
.039

.047
.056
.068
.082
.10

.12
.15
.18
.22
.27

.33
.39
.47
.56
.68

.82
1.0
.187
.187
.187
.187
.187

.187
.187
.187
.187
.203

.219
.250
.265
.234
.250

.281
.281
.296
.312
.344

.375
.375
.406
.437
.437

.500
.531
.531
.578
.625

.625
.687
.406
.406
.406
.406
.406

.406
.406
.406
.406
.406

.531
.531
.531
.656
.656

.656
.656
.656
.781
.781

.781
.906
.906
.906
1.031

1.031
1.031
1.156
1.156
1.156

1.406
1.406
1001
1501
2201
3301
3901

4701
5601
6801
8201
1002

1502
2202
2702
3302
3902

4702
5602
6802
8202
1003

1203
1503
1803
2203
2703

3303
3903
4703
5603
6803

8203
1004
.187
.187
.187
.187
.203

.187
.187
.187
.187
.203

.203
.234
.265
.281
.312

.296
.312
.343
.375
.375

.406
.453
.484
.484
.531

.593
.593
.656
.625
.687

.687
.734
.406
.406
.406
.406
.406

.531
.531
.531
.531
.531

.656
.656
.656
.656
.656

.781
.781
.781
.781
.906

.906
.906
.906
1.031
1.031

1.031
1.156
1.156
1.406
1.406

1.656
1.656
1001
1501
2201
3301
3901

4701
5601
6801
8201
1002

1502
2202
2702
3302
3902

4702
5602
6802
8202
1003

1203
1503
1803
2203
2703

3303
3903
4703
5603
6803

8203
1004
.187
.203
.234
.187
.187

.203
.218
.234
.203
.218

.265
.312
.328
.328
.359

.390
.421
.406
.437
.484

.453
.500
.546
.687
.578

.640
.687
.750
.825
.825

.906
1.000
.406
.406
.406
531
.531

.531
.531
.531
.656
.656

.656
.656
.656
.781
.781

.781
.781
.906
.906
.906

1.156
1.156
1.156
1.156
1.406

1.406
1.406
1.406
1.406
1.656

1.656
1.656
1001
1501
2201
3301
3901

4701
5601
6801
8201
1002

1502
2202
2702
3302
3902

4702
5602
6802
8202
1003

1203
1503
1803
2203
2703

3303
3903
4703
5603
6803

8203
1004
LEAD MATERIAL:
STANDARD LEAD SIZES:
TINNED COPPER SOLID WIRE
# 24 AWG: Up to and including .203" Dia.
# 22 AWG: from .204" thru .312" Dia.
# 20 AWG: .313" Dia. and over
 
CAPACITY TOLERANCE: STANDARD…± 10%
OTHER…from ± 20% to ± 1%
OTHER VALUES AS WELL AS VOLTAGE RATINGS ARE AVAILABLE ON REQUEST
MARKING: WESCO Logo, Capacity, Tolerance, VDC Rating and Date Code. (Note: On smaller units, (7) trademark will be substituted for WESCO logo.)
 


Wesco Electrical Company
41 INTERSTATE LANE WATERBURY, CT 06705
TELEPHONE: 203-755-3101 FAX: 203-755-0659











this data sheet

www.wescocap.com




This information was originally published on public access forums and websites, all information was made freely available
to the public by their authors and is merely saved here for reference.

The information on this page is an insight into the development of Gibson® re-issue bumblebee capacitors, it is not
a critque of Gibson® products or policy's, but is of interest to know the views and processes which occurred while
Gibson® was finding a suitable capacitor for the custom shop historic line of instruments.

Classic AmplificationTM neither endorses or critises the information given in these public posts.

Classic AmplificationTM is not affiliated with Gibson® or The Les Paul Forum®, or their trademarks in any way.