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2 - JBL D131 8-ohm speakers - $1 (Detroit)
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This offering is for a pair of vintage JBL D131 full-range 12” speakers, the predecessor to the famous D120.
• The 131 has a smaller voice coil gap resulting in a lower wattage speaker, approximately 30-40 Watts, with higher spl.
• The D131 has a paper surround where the later D120F has a cloth surround and has goop around it to bolster it.
• The gap on the D131 is smaller .053" compared to the D120F .057".
• The JBL D131 is stout and employs the same alnico magnet structure as the 15-inch D130.
Even though the labels state 16ohm, these coils measure as 8ohm speakers. In the early days JBL rated these higher in an effort to get more output from their hifi systems.
GUITARISTS WHO USED JBL: Eric Clapton. Eddie Van Halen. Stevie Ray Vaughan. Keith Richards. Jimi Hendrix. Duane Allman. Jerry Garcia. Albert Lee. Roy Nichols. Albert Collins. James Burton. Chet Atkins. Vince Gill. Mick Taylor. Eric Johnson.
JBL knew these were going into guitar amps, according to JBL engineer Harvey Gerst:
"Okay, lemme clear this up once and for all:
The only reason I raised the power rating on the "F" series is because the program source material had limited range. Typically, electric guitars go down to around 80Hz, but most of the energy is an octave above that, around 160Hz. The "why" has to do with string length, tension, and diameter - let's just say there's not as much fundamental there as most people think.
So, I knew that guitars were mainly putting out from about 160Hz to around 3kHz, with some harmonics probably going out to around 6kHz. Not exactly the hardest range to handle for a big ass 12" or 15" JBL speaker.
When it was time to really rate them, I brought them into the lab, hooked them up to our "monster Mac" - our tube 200+ watts McIntosh, and started to play guitar, while we watched where they started to crap out.
Everybody felt comfortable that increasing the published power ratings was a reasonable step. We weren't playing pipe organs or symphonies thru these things; they could handle more power simply because the instrument's range was severely limited.
Hopefully, that should clear up some misconceptions."
NOTES:
* The original aluminum dust cap was not added just for appearance. It also serves as a heat sink and raises the power capacity as well as enhances the mid-hi output.
*The alnico magnets designed and used by JBL (for the D and K series speakers) were of the finest quality available.
* JBL uses a reverse polarity on these models. With the speaker cone facing up, use a 9-volt battery and touch the terminals. Positive on the battery to the black (negative) terminal should cause the cone to jump forward (up).When wiring these speakers, place the positive (red or white) wire to the black terminal on the speaker and the negative (black) wire to the red terminal on the speaker. This will ensure that both your speakers have a forward motion with positive energy lie the speakers in the rest of the industry, thus eliminating any phase issues.
* When mounting these to a baffle board, be sure it is level (test it with a straight edge). Use all the nuts and bolts, taking special care that they are evenly torqued / tightened. Do NOT over tighten.
AUDIOHERITAGE.COM: “Personally I think the D131 represents something essential about the JBL history of speaker making. It is efficient, dynamic, beautifully made, technically SOA at its time…”
AUDIOKARMA.OEG: “… probably one of the Best ever guitar speakers.”
JBL D131:
A 30 cm cone type wide-range speaker unit that uses the same voice coil and magnetic circuit as D130.
The magnetic circuit is equivalent to D130, such as a voice coil of 10 cm in diameter and a magnet of 5.4 kg.
By driving the lightweight cone with a powerful magnetic circuit, transient characteristics are improved and dynamic range is expanded.
Type: 30 cm cone type full range unit
Sensitivity: 102db
Allowable input: 60W (continuous program)
Impedance: 8 Ω
Directional: 90 °
Sound pressure level (new JIS): 101dB(1kHz)
Voice Coil Diameter: 10.2cm
Magnet Assembly Weight: 5.4kg
Magnetic flux density: 12,000gauss
Recommended enclosure volume: 114L ~ 338L
Depth: 124mm
Weight (packed): 7.3kg (13.5 lbs. unpacked)
SOME JBL-RELATED VIDEOS WORTH WATCHING:
https://www.youtube.com/watch?app=desktop&v=s86IMKRbyt8&t=42s
https://www.youtube.com/watch?v=zXOUO1UE2OM
https://www.youtube.com/watch?v=KkWHDrwsh4Y
https://www.youtube.com/watch?v=Kp0Qkm9ycko&t=201s
https://www.youtube.com/watch?v=KpzwOlThTRo
Cash is king -- but PayPal “friends and family” and Venmo rule, too!
I’m in downtown Detroit but travel back and forth to Brighton often.
Thanks for looking.