Finally Got the JBL 4345

[Dev]

Hi, Greetings to everyone. After a long search I found a pair of 4345 and now waiting for the recone kit to arrive. Meanwhile thought of getting rid of that infamous :banghead: switch in the crossover.
Will share the pictures before I start disturbing you guys with my questions.

[Dev]

The crossover

[Dev]

The Switch in the Crossover of JBL 4345.
how to wire it directly without using this switch? I went through Warpigs thread , but that was a different kind of switch :dont-know: please advice how to go about it.

Thanks in advance.

[Dev]

Hi , can anyone let me know how to get rid of the Switch and wire it directly? Or just cleaning it with deoxit is good enough?
thanks

[Odd]

I have no experience with this filter but here is the wiring diagram.

You can see here what the switch does.



89865

[Earl K]

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=89829&stc=1&d=1635652772

By far the simplest approach is to bundle the mess off to someone who actually recognizes what they are looking at ( and then have that same person add 6 bypass wires at the proper locations // essentially doubling up the connections being made by the switch ) .

I would add//solder these bypass wires onto the lower "L-shaped" leads that are themselves soldered into the ( unseen ) circuit board traces .

Those switches are too heavily corroded for cleaner ( IME ). Cleaner won't remove that black oxidization ( only applied abrasion >> not recommended since the switch will fall apart under the duress of filing ).

:)

[Dev]

Thanks Odd for the diagram and thanks Earl, will sent it to a service guy. I don’t think I can do it myself.
Any pictures of how the wiring is done?

[Earl K]

Thanks Odd for the diagram and thanks Earl, will sent it to a service guy. I don’t think I can do it myself.
Any pictures of how the wiring is done?


There's no pic here at LHF ( that I know of ) that shows how to hardwire the switch ( into the input mode of your choice >> & BTW once you add the necessary 6 wires one is stuck with the choice of input mode made ).

If a tech ( or anyone else for that matter ) can't figure out for themselves ( which 6 pairs of tabs get hard-wired together for either input mode ) then they have no business mucking about inside these boxes crossovers ( IMO ).

:)

[Ian Mackenzie]

http://www.audioheritage.org/vbulletin/showthread.php?13930-JBL-3145-stock-crossover.-A-pictorial


https://jbl43.net/catalogs/networks/3145_Network.pdf

The first link is a thread l wrote which tells you concisely what each tab on the pcbs are for.

If you are planning on using the system in full passive mode put the crossover mode switch in the passive position.

1. Connect a new Black insulated 7.5 amp wire from the High Frequency input negative terminal to the woofer negative terminal.

Then connect a new Red wire from the High Frequency positive input terminal to the input side of the L101 5.4mH inductor.

No other changes are required.

If you plan to use the system in bi amp mode put the switch in bi amp mode.

1. Connect a Black insulted 7.5 amp wire from the Low input negative terminal to the woofer driver negative terminal.

2. Connect a Red wire from the Low input positive terminal to the woofer driver positive terminal.

3. Connect a Back wire from High Frequency input negative terminal to ground side of the L102 4.8mH inductor.

4. Connect a Red wire from the High Frequency input positive terminal to the input side of L2 1.8mH inductor.

No other changes are required.

How you decide to implement this is entirely up to you. These networks were not designed to be modified for diy end users.

If you wish you could attach crimp connectors to the wires and remove the existing crimp connectors as described on the inductors. The other end of the cables can be attached to the input terminals as described with a crimp connector.

You will need to be able to follow the schematic. For example L102 4.8mH inductor will require a ground connection to the pcb ground via an insulated wire and the Black wire from the High negative input terminal. This is because the inductor is not directly mounted on the pcb.

[Riley Casey]

Rewiring without the switch ( the no schematic reading version ).

Rotate the switch to the desired biamp or passive position.
Don't rotate it again after this.
Mark one of the switch posts with a flag of tape.
Mark the circuit board under the post with an X.
Assign a number to each contact counting from the marked post.
Remove the switch and clean out the holes in the PCB.
Note where the switch contacts are bridged by the contacts on the switch ( there are five such 'bridges' based on the schematic.
Solder a jumper between each pair of holes that match those bridged contacts.
Confirm that the number of the holes jumpered matches the number and location of the switch contacts that are bridged.




Thanks Odd for the diagram and thanks Earl, will sent it to a service guy. I don’t think I can do it myself.
Any pictures of how the wiring is done?

[Ian Mackenzie]

Having done this myself l would not recommend attempting to remove the switch unless the poster has experience in soldering and suitable tools. Damage to the pcb and the switch is likely which will impact on the marketability of the system.

The inductors have crimp spade terminals and it’s simple enough to connect with a crimp spade direct to the input terminals.

If you read the link to the pictorial the terminals on the pcb are all labelled and the wires are colour coded. If you haven’t got labeled cables that’s going to be an issue to sort out first.

As a rule most system owners construct a charge coupled network using the new equivalent 3145 crossover schematic with more modern parts and without the losses in these legacy networks assembly’s, The tapped auto transformers don’t perform as well subjectively as the new equivalent network.

In comparison the bypassed Mylar capacitors are muffled subjectively. The stock networks aren’t diy friendly.

[Dev]

Thank you Ian for the great help. You are such a wonderful person. High Regards.

:):):)





http://www.audioheritage.org/vbulletin/showthread.php?13930-JBL-3145-stock-crossover.-A-pictorial


https://jbl43.net/catalogs/networks/3145_Network.pdf

The first link is a thread l wrote which tells you concisely what each tab on the pcbs are for.

If you are planning on using the system in full passive mode put the crossover mode switch in the passive position.

1. Connect a new Black insulated 7.5 amp wire from the High Frequency input negative terminal to the woofer negative terminal.

Then connect a new Red wire from the High Frequency positive input terminal to the input side of the L101 5.4mH inductor.

No other changes are required.

If you plan to use the system in bi amp mode put the switch in bi amp mode.

1. Connect a Black insulted 7.5 amp wire from the Low input negative terminal to the woofer driver negative terminal.

2. Connect a Red wire from the Low input positive terminal to the woofer driver positive terminal.

3. Connect a Back wire from High Frequency input negative terminal to ground side of the L102 4.8mH inductor.

4. Connect a Red wire from the High Frequency input positive terminal to the input side of L2 1.8mH inductor.

No other changes are required.

How you decide to implement this is entirely up to you. These networks were not designed to be modified for diy end users.

If you wish you could attach crimp connectors to the wires and remove the existing crimp connectors as described on the inductors. The other end of the cables can be attached to the input terminals as described with a crimp connector.

You will need to be able to follow the schematic. For example L102 4.8mH inductor will require a ground connection to the pcb ground via an insulated wire and the Black wire from the High negative input terminal. This is because the inductor is not directly mounted on the pcb.

[Dev]

:):) Thank you Riley.



Rewiring without the switch ( the no schematic reading version ).

Rotate the switch to the desired biamp or passive position.
Don't rotate it again after this.
Mark one of the switch posts with a flag of tape.
Mark the circuit board under the post with an X.
Assign a number to each contact counting from the marked post.
Remove the switch and clean out the holes in the PCB.
Note where the switch contacts are bridged by the contacts on the switch ( there are five such 'bridges' based on the schematic.
Solder a jumper between each pair of holes that match those bridged contacts.
Confirm that the number of the holes jumpered matches the number and location of the switch contacts that are bridged.

[Ian Mackenzie]

I will draw you to sketch of the changes over the weekend.

[Dev]

wow, Thanks, Thank you so much.



I will draw you to sketch of the changes over the weekend.

[Dev]

I will draw you to sketch of the changes over the weekend.

Thank you Ian for the detailed drawing ( which you have send through mail) of the wiring , one speaker is done and will be doing the other this weekend. Need to polish the cabinet and fit the drivers.
Thanks again.
Dev

[Dev]

Hi, the stock caps in the 4345 was replaced with Clarity and Auricap . The Switch was bypassed and the binding post changed.
The initial results are promising even without burn in. Now need to replace the L pads with fixed resistors.
Thanks everyone for your kind help and a special thanks to Ian….you are indeed the “ YODA”
Regards
dev

[Chas]

FWIW, I’m still using the L-Pads in my 4345’s after owning them for nearly twenty years, but do rotate them every year or so. If you’re really keen on replacing them with fixed resistors, I would wait a year or two. It can take a long time to get four ways dialed-in.

[Tranquil]

Congratulations on the acquisition of your new speakers.

[Dev]

FWIW, I’m still using the L-Pads in my 4345’s after owning them for nearly twenty years, but do rotate them every year or so. If you’re really keen on replacing them with fixed resistors, I would wait a year or two. It can take a long time to get four ways dialed-in.

Hi Chas, I am planning to change the L pads only for the mid freq, since one L pad is giving lot of trouble.
Regards

[Dev]

Congratulations on the acquisition of your new speakers.

Thank you Tranquil :)

[Chas]

Hi Chas, I am planning to change the L pads only for the mid freq, since one L pad is giving lot of trouble.
Regards

Aha, got it. Best of luck with your 4345’s, they continue to amaze me after decades of service here.

[Dev]

Hello all, I bypassed the switch and wired it in Bi amping mode ( external x over) and I am not using external x over for the LF at this point of time. So I am using Jumpers in between the binding post and using a single Tube amplifier , but the system lack dynamics ……
since I wired it in bi amp mode , the signal to the LF doesn’t come through the internal crossover? ( though I use jumpers between the binding post) Do I need an external crossover and an amp for LF if the switch is bypassed and wired in external x over mode?
Thanks and Regards

[speakerdave]

Hello all, I bypassed the switch and wired it in Bi amping mode ( external x over) and I am not using external x over for the LF at this point of time. So I am using Jumpers in between the binding post and using a single Tube amplifier , but the system lack dynamics ……
since I wired it in bi amp mode , the signal to the LF doesn’t come through the internal crossover? ( though I use jumpers between the binding post) Do I need an external crossover and an amp for LF if the switch is bypassed and wired in external x over mode?
Thanks and Regards

Aha, so this was the plan! I've scanned the thread and must have missed where you asked about this step in your project. If you have done this thinking of other JBL speakers which use jumpers, please understand that they may not have switches, thus do not remove anything from the circuit, except the jumpers, for bi-amping, or more likely, bi-wiring.

I assume there is a reason for not having the woofer amp and external line-level crossover at the ready—like not yet having found the right deal, yes? Yes, you need them both.

Now that you have asked about it after doing the mods, my suggestion would be to look into the future and see how far off the amp and crossover are, realistically; then decide to forego the speakers or restore the circuit and give yourself time to find the equipment you need. I know it's a bit tedious to think of modding, unmodding, then remodding, but what else are you going to do?

You may like the speakers just fine using only one amp full range.

[Tranquil]

Aha, so this was the plan! I've scanned the thread and must have missed where you asked about this step in your project. If you have done this thinking of other JBL speakers which use jumpers, please understand that they may not have switches, thus do not remove anything from the circuit, except the jumpers, for bi-amping, or more likely, bi-wiring.

I assume there is a reason for not having the woofer amp and external line-level crossover at the ready—like not yet having found the right deal, yes? Yes, you need them both.

Now that you have asked about it after doing the mods, my suggestion would be to look into the future and see how far off the amp and crossover are, realistically; then decide to forego the speakers or restore the circuit and give yourself time to find the equipment you need. I know it's a bit tedious to think of modding, unmodding, then remodding, but what else are you going to do?

You may like the speakers just fine using only one amp full range.
I have been following this thread and I have a question as to the function of this bi-amp switch. Is this switch separating the woofer from the internal crossover, giving the option to use an external active two way crossover, sending the low Hz output to one amplifier which is connected to the woofer and the Hi Hz output to another amplifier connected to the input of the internal crossover. Lo Hz crossover point selected at the active crossover?

[robertg]

I have been following this thread and I have a question as to the function of this bi-amp switch. Is this switch separating the woofer from the internal crossover, giving the option to use an external active two way crossover, sending the low Hz output to one amplifier which is connected to the woofer and the Hi Hz output to another amplifier connected to the input of the internal crossover. Lo Hz crossover point selected at the active crossover?
Yes.

[Dev]

Aha, so this was the plan! I've scanned the thread and must have missed where you asked about this step in your project. If you have done this thinking of other JBL speakers which use jumpers, please understand that they may not have switches, thus do not remove anything from the circuit, except the jumpers, for bi-amping, or more likely, bi-wiring.

I assume there is a reason for not having the woofer amp and external line-level crossover at the ready—like not yet having found the right deal, yes? Yes, you need them both.

Now that you have asked about it after doing the mods, my suggestion would be to look into the future and see how far off the amp and crossover are, realistically; then decide to forego the speakers or restore the circuit and give yourself time to find the equipment you need. I know it's a bit tedious to think of modding, unmodding, then remodding, but what else are you going to do?

You may like the speakers just fine using only one amp full range.


Thank you Dave, this weekend I am going to remod the crossover back to internal mode. to keep things simple I prefer a single amp. This project is full of fun and a lot of learning for me and you guys are just awesome:applaud::applaud::applaud:

Regards

[Dev]

So the wiring is done in passive mode and happy with the end result ( though the bi amp mode with external x over sounded even better)
Changed the cap, replaced the L pad in the mids with resistors , the binding post are new and the switch is bypassed and i am more satisfied with the new sound. More intimacy , better clarity and more life to the music.
Thanks a ton to Ian Mackenzie for the help and answering all my mails.
Thanks Riley and all others who gave valuable inputs.
Regards

[Ian Mackenzie]

Hi Dev,

That’s a very nice set up.

Where are your slant plate horn lens?

Can you tell us about your hifi components?

Ian

[Dev]

Hi Dev,

That’s a very nice set up.

Where are your slant plate horn lens?

Can you tell us about your hifi components?

Ian


Hi Ian, thanks for the compliment. The Lens were missing when I purchased the speaker. Need to order it from eBay. How important are those lenses?

My audio equipment is all digital.
Proceed CDT 3 transport / Aurender S10 streamer / Denafrips Terminator / Conrad Johnson CT 5 pre and Conrad Johnson LP70s power .

Regards

[Mr. Widget]

My audio equipment is all digital.
Proceed CDT 3 transport / Aurender S10 streamer / Denafrips Terminator / Conrad Johnson CT 5 pre and Conrad Johnson LP70s power .
Nice setup!
How do you like the Aurender? A friend has the Aurender W20SE and loves the sound but is rather frustrated by the interface.


How important are those lenses?
Probably more important that a crossover rebuild. ;) You should track a pair down.

http://www.lansingheritage.org/html/jbl/reference/technical/lens.htm


Widget

[Dev]

Nice setup!
How do you like the Aurender? A friend has the Aurender W20SE and loves the sound but is rather frustrated by the interface.

Probably more important that a crossover rebuild. ;) You should track a pair down.

http://www.lansingheritage.org/html/jbl/reference/technical/lens.htm


Widget

Thank you Widget :) The Aurender is a great streamer , slightly slower then the LUMIN, but much better sound quality. Tried few streamers before settling down to Aurender and the iPad interface is not that bad :)

Regards



Regards

[RMC]

The lens provide proper sound dispersion in the room, so they are important...

If you cannot find the right JBL lens you may want to look at McCauley Sound they made similar aoustic lens that may also be offered on EBay?

Richard

[Dev]

The lens provide proper sound dispersion in the room, so they are important...

If you cannot find the right JBL lens you may want to look at McCauley Sound they made similar aoustic lens that may also be offered on EBay?

Richard


Thank you RMC, Kenrick sound offers lens on eBay. Will also check McCauley Sound.
regards

[Mr. Widget]

Thank you RMC, Kenrick sound offers lens on eBay. Will also check McCauley Sound.
regardsThe ones that Kenrick offers are very faithful reproductions and are well made. Short of finding an original pair, I would go with the Kenrick lenses.


Widget

[Dev]

The ones that Kenrick offers are very faithful reproductions and are well made. Short of finding an original pair, I would go with the Kenrick lenses.


Widget

Hi widget, point noted abt kenrick lenses, will be ordering them only on September though.
regards

[mattking52]

Rewiring without the switch ( the no schematic reading version ).


Note where the switch contacts are bridged by the contacts on the switch ( there are five such 'bridges' based on the schematic.
Solder a jumper between each pair of holes that match those bridged contacts.
Confirm that the number of the holes jumpered matches the number and location of the switch contacts that are bridged.

For the record, there are actually six 'bridges' on the switch connections, per the schematic and the PCB.

It looks like Dev has already figured out the wiring, but in case it's helpful to anyone consulting this thread later, I'm including a diagram here that I used when removing the switch and replacing it with individual wire jumpers. The black connections (drawn on the PCB) denote the placement of the six jumpers for full passive mode ("Internal Crossover"), and the red connections denote the placement of the six jumpers for bi-amp mode ("External Crossover"). I tried the wires in both positions, and confirmed proper operation.

I've long since moved to a bi-amp configuration with a First Watt B4 and my own charge-coupled external crossover PCBs. Dev: I highly recommend the charge-coupled, bi-amped configuration as part of your explorations with your 4345s. Have fun and enjoy the ride!

[Dev]

For the record, there are actually six 'bridges' on the switch connections, per the schematic and the PCB.

It looks like Dev has already figured out the wiring, but in case it's helpful to anyone consulting this thread later, I'm including a diagram here that I used when removing the switch and replacing it with individual wire jumpers. The black connections (drawn on the PCB) denote the placement of the six jumpers for full passive mode ("Internal Crossover"), and the red connections denote the placement of the six jumpers for bi-amp mode ("External Crossover"). I tried the wires in both positions, and confirmed proper operation.

I've long since moved to a bi-amp configuration with a First Watt B4 and my own charge-coupled external crossover PCBs. Dev: I highly recommend the charge-coupled, bi-amped configuration as part of your explorations with your 4345s. Have fun and enjoy the ride!

Hi Mattking , very kind of you to share the diagram.
Just now completed upgrading the caps in my stock x over, so the CC should be a project after few years
Thanks

[Ian Mackenzie]

Hi Matt,

Great to see you post.

[mattking52]

Hi Matt,

Great to see you post.

Thanks, Ian! Been a while.
Hope all is well with you.

[Dev]

Hi, hope everyone is doing fine.
Will an Accuphase Class A amplifier, like E 600 or E 650 ( 30 watt) drive the 4345. I never crank up the volume ( max 80db). Room size 20×14 feet
I know bi-amping is the best , but that upgrade need to wait for an year or so.
Thanks for your time and waiting for your advice
Regards

[Mr. Widget]

Hi, hope everyone is doing fine.
Will an Accuphase Class A amplifier, like E 600 or E 650 ( 30 watt) drive the 4345. I never crank up the volume ( max 80db). Room size 20×14 feet
I know bi-amping is the best , but that upgrade need to wait for an year or so.
Thanks for your time and waiting for your advice
RegardsI like small class A amps. Give it a shot.

You could always pick up an active crossover, and drop in a heavy iron class AB amp on the 18" woofers.


Widget

[Robh3606]

I like small class A amps. Give it a shot.

You could always pick up an active crossover, and drop in a heavy iron class AB amp on the 18" woofers.


Widget

He could also turn up the Mid, Hf and UHF pots up to increase sensitivity when bi-amping. Get a bit more headroom.

Rob :)

[Dev]

Thanks Widget and Rob, it's a blind buy and I may go for it.
Regards