https://jamminjersey.com/detail/0074...-slot-tweeters
Click on the link and you can email Mark Leonard. I bought a large shipment recently and it was well organised.
Ian, Thank You. I placed the order today for the 2405H's. once I receive these, I will have all the JBL drivers to start the build. I also picked up some foilcals for the my project. I just need the pot covers for the pots to look like the originals. I now need to pick up some more wood for the cabs, I already have half of it.
I dropped off the the 2245H's woofers yesterday to Upland Speaker repair to be reconed. So once I get these back I will send the 2123H's in to him to be works on as well (the one I accidently messed up while unpacking it).
No worries,
I might ask you to return a favour at some point.
Is it just me or have 2405 prices skyrocketed lately. 077s even more so.
Yes. Particularly if searching for them in EBay. And you don’t know what condition they are in.
From Jammin Jersey they check everything and tell you if it’s original diaphragms etc. l am saying this on experience with a large shipment of drivers. Everything was double boxed and carefully packed. We also have Edgewound who can pretty much repair or re build most things. His work is exceptional.
Today I bought some speaker mounting kits for the 2245H's. So now I just need to find a source for the knobs for the L-pads. The one's I'm finding are expensive, the cheapest are $69 for 4.
Try Parts Express
I went there but nothing. I did find an old thread that had some that looked like the originals over on the EHC website.
http://www.ehcknobs.com/index.php?id=PO
I need to call them tomorrow and see if I can buy them and what the min purchase quantity is.
Here are some pics of mine JBL 2420 with 2307 horns. They are in really good condition except for the circle type scratches on one of them. If it wasn't for those scratches these would have been in mint condition.
They also measured 6.0 ohms for one and 6.2 ohms for the other. These were said to come out of a working cab. The only other issue is the push button speaker post were loose, so I just tighten them up. I already ordered the 16 ohm replacement diaphragms, so these should be here by Friday.
So now I'm just waiting on the 2405s to come in next, maybe late this week or early next week.
All seems to to be coming along pretty smoothly for now, hopefully it continues that way.
They are nice
Hello, I had this info on my laptop but it died on me a year ago. I can't locate any info for the original JBL 4345 raw driver impedances. I just want to make sure that the 2420 and 2405 are what they are supposed to be. What I have is the 2420 is 16 ohms on the label but they measure 6.0 and 6.2 ohms, so this would be the 8 ohms. I have already order the 16 ohms diaphrams to match the label on the 2420 driver's. I haven't received the 2405's yet so I don't know if they are 16 or 8 ohms.
All the 4345 network schematics I have seen here show the drivers I have and a few that show 8 ohm pots which lets me know those are 8 ohm drivers being used for those networks, but can't find any original 4345 network schematics with the driver's impedance.
Was there any 4345 crossover networks that used 16 ohm drivers for the 2420 and 2405? I want to make sure before I place orders for NEW replacement diaphrams on the 2405's. Thanks!
It’s a first world problem with building these vintage systems.
To explain the actual measured ac impedance of the nominal 16 ohm drivers is around 12 ohms.
The dcr as l recall is around 6-7 ohms.
The newer compression drivers with titanium diaphragms are/were available in a 8 ohm labelled impedance. The dcr on those is around 3-4 ohms.
The 2405 has a measured impedance of about 10 ohms
Jbl approach to labelling impedance has always created impedance.
Looking at the 3145 networks there is a 20 ohm resister across the compression driver. This has the effect of making the drive look like an 8 ohm load for the 8 ohm L pads.
You most likely have the right diaphragms. If the compression driver was in fact a Jbl marked 8 ohm version just leave out 20 ohm resister.
Ok, so lets see if I got it.
2420 with 8 Ohm diaphrams (measure 6.0-7 Ohms) remove the 20 Ohm resistor from the network?
2420 with 16 Ohm Diaphrams (measure 12 Ohms) leave the 20 Ohm resistor in?
Does this rule still apply if I want to use the "Super 3145" network?
Thank You for all the help!
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