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Get familiar with the reaction system: Introducing the Reaction System
JBL E140-8
Started a build yesterday for bass cab to go with the aquired Ampeg V-4B. Wanted something vintage and always admired JBL stuff. Can't afford what people want for the D140's, so it was a K or E. K's can also bring a premium price as it's an Alnico unit as well, which led me to a really nice original E140.
Frequency response:
Impedance and T/S parameters:
Comments
These are commonly used in a 4cf@40Hz box, so I ran the numbers and seems to be fine with that.
The width of the amp is 27" , I wanted it up as far as possible, so I ended up with 30" high and 12" deep. I leaned the baffle back a few degrees for a little dispersion aid. With the baffle set back I ended up around 4.3 cubes. Should come close to the 4 once ports, driver, and bracing happens.
I build them with a removable back because it makes covering easier, avoiding big bunch of seams. Used 1/2" ply for the cleats, sides, top, and bottom.
Got the back cut and the baffle made/mounted today. I used 3/4" for those. Added another 3/4" thick ring behind the driver opening for mounting hardware. Freak weather break is nice👍🏼
Added some 1/2" strips to the front edge to beef it up a bit, looks better. The pieces are a little proud, thought I had a top bearing flush bit, but I didn't, have to go pick one up. Hope to get all the round overs done before the weather turns crappy again.
Yeeesssss , black tolex ? Maybe knock down a few of those corners ?
LOL NM , spoke too soon. Yeah very cool !
Yeah, right now I'm at black tolex and some sorta red/oxblood color grill cloth.
Might as well drop a link to the Ampeg project. Lots of ups and downs.
https://www.talkbass.com/threads/nad-ampeg-v-4b-project.1583026/
Baltic Birch? Looks nice/ void free. 9 ply and 5 ply?
Got hooked up by my buddy. He's in the veneer business and scored a pallet of off cuts and rejects.
SCORE!
Sweet!
That's a great score! Prices for nice plywood like that is ridiculous these days.
For some reason, I recall JBL drivers being labeled with reverse polarity, so that might be something you should verify.
InDIYana Event Website
So after reading through your build thread , are you in need of some 6L6 tubes? I think I have a pair someplace after replacing them with some Electro Harmonix 6L6's. I think they are of the Fender groove tube flavor...
Ben, you'd be correct. It has red and black terminals, and I hooked it up red to red. As you can see on the impulse graph it's reverse.
Nicolas, I appreciate that, but it's supposed to have 7027A's. I'm gonna go back with those. Although the 6L6 is a proven tube in this amp, the specs on the Svetlana's in it say max 500V, the 7027A's are 600V. I measured 536V at idle.
Got a baffle to back brace made, threw some speed holes in for some really fast bass and all.😛
Then knocked out the handle openings. Had a gift card from Lowe's, so ordered up the top bearing flush bit.
Skeletonized brace, you must have had a day off.
sovtek branded , rebranded by Fender
All the routing is done and sanded. Got the input terminal cup done, too. Ran out of gasket material, so when that shows up I can assemble enough to check cab tuning
Put it all together to see where the tuning ended up. It ended up at 30Hz with the two 3" aeroports as short as they'd go. I removed the inner flare and it responded with 40Hz. So I took the flares to the band saw and epoxied them together to yield an overall length of 3.5".
Hooked it up to the Hartke, because I had to hear it, ehh!! Holy crap! This speaker is pretty bitchin🤘🏼. I was not let down one bit on the JBL magic. I get it, I totally get it, and this is just an E series. Can't wait to hear it with the Ampeg.🔥
I assume you shortened the port tubes to raise the box tuning frequency, yes?
Yes.
Impressive work and speed of construction with such fine woodworking detail.
Everything Eric builds is awsome. He's no hack that's for sure.
Completely true! Nice job as usual Eric.
Great build! Amazing how that "old tech" driver can sound so great.
I also like the camshaft lamp!
Is that a Losi?
https://www.jfcomponents.com/
>
Wow! Totally missed seeing that. Agreed, that is badass!
You need to see the drawer pulls on his bench.
Thanks guys!! Should look even more bitchin when the tolex goes on.
Yes, my old losi XX4. Retired. Got the bug again after renting a buggy at an indoor off-road track that's like 10min from me. To many expensive hobbies, y'all know the deal. Heck I still have my old JRX2 ProSE !😛
Better pic of the lamp. I made it probably 20 years ago? I'm working on another lamp using an old JBL speaker.
I made the cone light up, still have to make the rest.
Drawer pulls🤘🏼
LOL on the door pulls , F'in fantastic and also , glorious !!
RCs are fun no matter how old you are! We never got big into racing, but our youngest worked at a hobby shop that held races almost every weekend. We did a lot of crawling with our Axial scalers. Trashed a few steering servos with those trucks!