4345 4355 networks

[kartsmart]

I need to build up some cc networks to finish up my project and need to know what is the final drawing I need .

I am using 2245
2123 H
2441 2441 dia. ( will later change to 2452 HSL }
2405



Has anyone a parts list for partsexpress ?
what brand name of parts are prefered ?
how much does it cost to buld a set ?

[Woody Banks]

The drawing for the CC 4345 network submitted by Giskard can be found @ http://www.audioheritage.org/vbulletin/showthread.php?10613-4345-Includes-Designer-s-Post

[kartsmart]

Thanks woody what I was looking 4 was the 4355 equiv. networks I am using the 2123 and 2441 - 2311 combo

[Woody Banks]

Sorry, I was having another senior moment. Your component choice should produce some really ourstanding results. I ended up building the 3155 equivelent, thanks to Giskards post.
A good friend has a system using components very similar to yours but has gone with a full four-way active Marchand crossover and a quad amp setup that produces jaw dropping results. Of course he is a Marchand dealer and the cost involved would exceed the charge coupled 3155. Good luck on your quest.

[kartsmart]

I am using 2 2496 begr. crossovers at times I get the same results but trying to keep 4 amps and 2 active crossovers working good at the same time makes it quite a hard time ! cable humm ect digital on this scale just dont quite get it . :crying:

[Odd]

I think you will find answers to some of your questions here (http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project)

[kartsmart]

Is this the network I want when using the 2123H http://audioheritage.org/vbulletin/showthread.php?p=243739#post243739 ?
How important is the dcr for the iron core inductors , does it have to be exact I don't see the same values listed for some anywhere ?
Last but least but not to start another capacitor topic war, but what caps are working out the best for these 4345s = bang for the buck
where is the best places to buy parts here in the usa

[Earl K]

> This is the network I believe you should build up, if you want to copy Giskards super build ( just be aware that it was biamp only ).

> Giskard has stated repeatedly that he found that the 2123H to be such a close match to the 2202H ( just a couple of db less efficient ) that he simply used the N3155 schematic as the base network for his super 4345 .

JBL 3155 ( original ) schematic (http://www.jblproservice.com/pdf/Network Schematics/3155 Network.pdf)

> Read what Mr. Widget did here (http://www.audioheritage.org/vbulletin/showthread.php?774-4355-3155-clones&p=6084&highlight=3155#post6084) ( relating to the question about adding back in, Lpads into the stock network ) .

> Because the tapped inductor ( within the original 3155 ) is no longer available ( & no longer preferred in actual usage ) all would-be builders are directed to the following network ( because it eliminates the tapped coil ) .

> SO: Here's the 3155 equivalent ( from 2003 ) , as worked up by GT & Giskard .

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=869&stc=1&d=1063439339

> To C.C. this newtork, simply double the value of the capacitors ( leave out the bypass caps ) , and double the quantity of the caps .
> Twin the caps ( insert them in series, in place of the original values ) .
> Where each pair of ( twinned ) caps are joined togther , add a 2 to 3 meg resistor ( to be fed individually from the + side of a 9V battery ) .
> Connect the minus side of the battery to the ground side of the network .
> Use Solen caps . They work really well in CC networks .
> ( At a quick glance ) I would use Solens', 16ga, air-core coils for everything but the 2.4mH inductor / where I would use whatever coil type was affordabe, as long as it had a dcr less than .4 ohms .

:D

[kartsmart]

Thanks Earl, this is exactly the answer I was looking for.

> To C.C. this newtork, simply double the value of the capacitors ( leave out the bypass caps ) , and double the quantity of the caps .

As a example if it called for 8UF I would use 2 16UF in series correct ?

as for 8ohm or 16ohm diaphragm the only change would be Lpad ?

[Earl K]

As a example if it called for 8UF I would use 2 16UF in series correct ?

> Correct !


as for 8ohm or 16ohm diaphragm the only change would be Lpad ?

> That's not correct .

> Changing the impedance for any of the 3 driver types ( from what a stock 3155 expects to see ) will necessitate at the very least, a partial rework of the network ( which you obviously don't want to manage on your own ) .

> My advice; Either keep with the program ( use official 3155 component impedance values ) or be prepared to pay someone to design a custom network for you / ( note; it's probably cheaper to simply buy the correct impedance diaphragms ).

:D

[kartsmart]

2441 were avaialble as 8 ohm or 16 ohm units, H OR J designations.
my drivers measure 8 ohms so I should have 16 ohm Dia. ?

[Earl K]

2441 were avaialble as 8 ohm or 16 ohm units, H OR J designations.
my drivers measure 8 ohms so I should have 16 ohm Dia. ?



> If your 2441s measure 8 ohms (dcr), then you don't need new diaphragms for your drivers to work with the N3155 .

> I just measured the DCR for (3) 2441 drivers . They are all @ 8 ohms dcr .

> BTW, though the 2441 ( could be said to carry a "J" ) designation ( in todays parlance ) , but it didn't ( historically ) .
> It was simply known as a 2441 ( period, end of story ).

> The 2441 was only available with a single impedance ( aluminum domed ) diaphragm .


:D

> The "H & J" designations didn't come into being until the introduction of the ferrite versions of these Pro drivers.
> That designation never existed in the days of "everything Alnico" .

[kartsmart]

To cc I under stand that I need to double the value of the cap and 2 in series .
The question I have is If I can not find the value I need the print witch shows I need to double the value of 18 uf x2 = 36uf example-- can a 33uf in series with a 39 work or do I need t parallel 2 cap to = 36 using 4 caps ?

[Lee in Montreal]

Capacitors' values add-up when in parallel. Per exemple, a circuit with four 9µF caps in parallel makes 36µF :bouncy:

[Earl K]

To cc I under stand that I need to double the value of the cap and 2 in series .
The question I have is If I can not find the value I need the print witch shows I need to double the value of 18 uf x2 = 36uf example-- can a 33uf in series with a 39 work or do I need t parallel 2 cap to = 36 using 4 caps ?

(i) Please use the word "which" from now on . ;)

(ii) The final value of all capacitors wired in series, is found by totaling their reciprocal ( "1/x" ) values ( this formula works for 2 or more caps ) .

eg ; Total Capacitance of 39uF & 33uF in series ?

> 1/39 ( 0.25641026 ) + 1/33 ( 0.03030303 ) = ( 0.055944056 ) = 17.875 ( which is close enough in most applications )

(iii) What you might want to calculate ( assuming one has a 33uF cap ) is found by this math ;

1/18 ( 0.055555556 ) minus 1/33 ( 0.03030303 ) = ( 0.025252525 ) = 39.6 ( uF ) to be exact


or if one has a 39uF cap , then ;


1/18 ( 0.055555556 ) minus 1/39 ( 0.0256441026 ) = ( 0.02991453 ) = 33.43 ( uF )

> Those odd values can be arrived at by paralleling small value caps onto the larger cap ( as mentioned by Lee ) .

:)

[4313B]

I thought I'd posted my final 4355 equivalent schematic. I'll have to look through my LEAP files and find it again.

[hjames]

I thought I'd posted my final 4355 equivalent schematic. I'll have to look through my LEAP files and find it again.
Thank you VERY much!

[Uncle Paul]

I thought I'd posted my final 4355 equivalent schematic. I'll have to look through my LEAP files and find it again.


This is by any chance? http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project&p=292188&viewfull=1#post292188

Dammit, reading through that thread again gives me crazy ideas...

[Earl K]

> Hmm, forgot about that thread ( thanks Paul ) ~

> Here's the network from that thread ( maybe it's not final / it is missing the Lpads );

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46834&stc=1&d=1280446056

Some Voltage Drives ;

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=48213&stc=1&d=1288356468

Pic with Lpads in place ( showing impedance stabilizing coils ) ;


The second photo shows the L-Pad board with the 3.5 mH 7.5 ohm and 1.0 mH 7.5 ohm inductors.

16 ohm L-Pad in front of the 376/2441/2445J (instead of the R13, R14, R15 sim)
8 ohm L-Pad in front of the 077/2405 (instead of the R10, R11, R12 sim)

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46973&d=1281711970



:)

[CauYem]

How does an impedance stabilizing coil work when connects to the L-Pad?
What value do you use?
How do you connect to the L-Pad?

[Earl K]

How does an impedance stabilizing coil work when connects to the L-Pad?
What value do you use?
How do you connect to the L-Pad?

> Think of it as a reverse Zobel circuit .

> So rather than flattening an impedance curve as frequency increases / it flattens ( an impedance curve ) as the frequency decreases .

> I believe Giskard has them wired directly across the drivers' 2 terminals .

> The Lpad was most likely just a convenient "standin" for the drivers own terminals ( "parallel is still parallel" , at either end of the wire ;) ) .

> Values are dictated in the same manner that a Zobels values are dictated .

:)

[kartsmart]

So I am confused what print is the right one ?

[Earl K]

> I'd go with a build-up of the 2010 version ( including the previously mentioned Lpads ) .

:D

[4313B]

This is by any chance? http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project&p=292188&viewfull=1#post292188


Yep, that's the one. Thanks for finding it.

R10, R11, R12 and R13, R14, R15 simulate real L-Pads. Just use L-Pads instead of those resistors. 16 ohm L-Pad on the 2441 and 8 ohm L-Pad on the 2405.


The L-Pad board in the photo above was for the 4344 MkII network that I also tried. The compression driver has the 1.0 mH 7.5 ohm DCR coil across its terminals and the 2123H has the 3.5 mH 7.5 ohm DCR coil across its terminals as per Greg's schematic.

Listening to the 4344 Mk II network side by side with the 4355 network I personally preferred the 4355 network, greater power and dynamics, which is what I expect from such a large loudspeaker.

The 4344 MK II networks are now in saeman's personal pair of 4344's. They really were intended for the single fifteen-inch based system. Turning all the L-Pads up 2 dB for the 2245H or 3 dB for the dual 2235H's didn't really cut it. ;)

[4313B]

Those voltage drives are from Greg's designs in the early 80's. One is of the stock 4345 (April 1981), the other two are from the two different versions of the 4355 (May 1981 and September 1981, reshape of the 2441 drive).

[4313B]

> This is the network I believe you should build up, if you want to copy Giskards super build ( just be aware that it was biamp only ).Interestingly, most people want full passive networks rather than bi-amp only networks. It is more convenient I suppose.

[kartsmart]

Just checking before ordering parts L4 470u is the same as .47mh ?

[Baron030]

Hi Kartsmart
470u is 470 micro-henries, which is equal to 0.47 milli-henries.
So, you are correct. Good luck with your project.
Baron030:)

[4313B]

Yes. They should all be standard Solen parts orderable from their website. I usually just shoot them an email and then call Dominique with my credit card number after she responds that everything is in stock.

[kartsmart]

Went to order part from solen everything seemed good until the shipping charges was applied, $163.00 can this be right ? :eek: E-mailed them but no reply. This will sure put this project over budget

[4313B]

I never use their automated ordering process. I think a few others have tried and gotten the same outrageous shipping amounts. Just email them with your order and your shipping address. They should respond with a quote in a day or two.

[ago2001]

Hi all, and many thanks for your great job in this forum.

regarding this post
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=15377&stc=1&d=1146736401

external crossover should really have a 18db/oct slope? sometimes I've found sometimes a 12db/oct value .....

thanks,

ago

[kartsmart]

Been in hospital for the last 3 months looking forward to get back to this project when I'm able !

[kartsmart]

> Hmm, forgot about that thread ( thanks Paul ) ~

> Here's the network from that thread ( maybe it's not final / it is missing the Lpads );

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46834&stc=1&d=1280446056I

Some Voltage Drives ;

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=48213&stc=1&d=1288356468

Pic with Lpads in place ( showing impedance stabilizing coils ) ;



http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46973&d=1281711970



:) I am finishing up my 3155 cc networks \ I have 2 questions \ 1 hooking up the Lpads does the terminal 3 go to crossover and terminal 2 go to the driver and terminal 1 go ground / as in the 4344 MK ll networks ? question 2 - is the EQ for the 2202-2441-2405 used [ N4 N5 N6 K4 K5 K6 } if so is it both the K and N - and what would the value be ? the 2202 is replaced with the 2123H as what 4313B did .... thanks for any help

[4313B]

I am finishing up my 3155 cc networks \ I have 2 questions \ 1 hooking up the Lpads does the terminal 3 go to crossover and terminal 2 go to the driver and terminal 1 go ground / as in the 4344 MK ll networks ?Yes.


question 2 - is the EQ for the 2202-2441-2405 used [ N4 N5 N6 K4 K5 K6 } if so is it both the K and N - and what would the value be ?Those are just labels. They mean nothing. EQ was my notation for "Equivalent". N4, N5, N6 are nodes for voltage drives in LEAP.

Everything in that schematic including and to the right of S6 and S8 is nothing to concern yourself with. Just replace all that stuff with normal L-Pads. It looks like the L-Pad on the 2441 is supposed to be 16 ohms and the L-Pad on the 2405 is supposed to be 8 ohms.

[kartsmart]

Thanks for your time to answer my questions , hopefully i will get these done , I had one of the worst years of my life !!! once again Thanks !!! :D

[kartsmart]

Yes.

Those are just labels. They mean nothing. EQ was my notation for "Equivalent". N4, N5, N6 are nodes for voltage drives in LEAP.

Everything in that schematic including and to the right of S6 and S8 is nothing to concern yourself with. Just replace all that stuff with normal L-Pads. It looks like the L-Pad on the 2441 is supposed to be 16 ohms and the L-Pad on the 2405 is supposed to be 8 ohms.


just would like to check - what would the the polarity connections be for the drivers / 2123H 2441 2405 / and biamped 2245

[kartsmart]

Im guessing + to black for 2123 2241 2404 ? :blink:

[kartsmart]

i give . please what is the answer :banghead:

[4313B]

Im guessing + to black for 2123 2241 2404 ? :blink:I Googled 'JBL 3145', went to their website and it looks like they did just that on the top three transducers.

http://www.jblproservice.com/pdf/network schematics/3145 network.pdf

[Hans Bleeker]

Old thread but might help people building these nowdays, I have build both networks, the one with and the one without coils, The one without did every thing perfect except that it has some harsness in the vocal range ön the 2" driver if you have a huge choir . On the other hand the non coiled version seems a litle bit more dynamic and open to me. So I personaly feel, for slam take the non coil'd and for accuracy the coiled.

[martin2395]

Yes Hans, it's still very helpful. A thread may be old but as long as there are people using big vintage 43's any info is appreciated :)
I bought a pair of 2123H (Sorry, no more stock looking 4343 :() which I hope to receive at the end of this week and thus with the 2123H and 2441's I won't be able to use Giskard's 4344MkII networks but instead I need the 4355 ones.

What kind of "2 did you use, the 2446 with Ti dia's?

[Hans Bleeker]

2445 with Aquaplas , 2446 somehow doesn't fit in, I cant explain why but 2445 is way better sounding in this combination. Doesnt matter what membames I use btw, Ribd Flat or Aqua, aways the same difference.

[ivica]

Old thread but might help people building these nowdays, I have build both networks, the one with and the one without coils, The one without did every thing perfect except that it has some harsness in the vocal range ön the 2" driver if you have a huge choir . On the other hand the non coiled version seems a litle bit more dynamic and open to me. So I personaly feel, for slam take the non coil'd and for accuracy the coiled.


2445 with Aquaplas , 2446 somehow doesn't fit in, I cant explain why but 2445 is way better sounding in this combination. Doesnt matter what membames I use btw, Ribd Flat or Aqua, aways the same difference.

Hi Hans Bleeker,
You said "coils", are there "Zobel impedance compensating coils" or something else?
Can you show the networks schematics?

Do you use 2311/2308 horn-lenses combo, or some others?...

As I have remembered 2445 driver with some other horns, not 2311 can produce narrow, but deep notch around 10kHz.

http://www.audioheritage.org/vbulletin/showthread.php?34180-2445J-with-2311-Horn&p=345210&viewfull=1#post345210

http://www.audioheritage.org/vbulletin/showthread.php?34180-2445J-with-2311-Horn&p=350117&viewfull=1#post350117

while 2450 (I think very very similar to 2446) has not such behavior

http://www.audioheritage.org/vbulletin/showthread.php?34180-2445J-with-2311-Horn&p=353522&viewfull=1#post353522


Regards
Ivica

[Hans Bleeker]

Hi Hans Bleeker,
You said "coils", are there "Zobel impedance compensating coils" or something else?
Can you show the networks schematics?

Do you use 2311/2308 horn-lenses combo, or some others?...

As I have remembered 2445 driver with some other horns, not 2311 can produce narrow, but deep notch around 10kHz.


Regards
Ivica

I ment the inductors as you can see in one of the schematics in this post, 4313 made that network without the replacement inductors for the tapped transformer, I use the drivers as in these schematics as in this post, so with a 2405 on top from 10Khz.
Its not the frequentie response, it has to do with soundstage, the soundstage is what ever horn I use , deeper and more coherent with the 2445 then with the 2446, its a small difference but noticable. Sinds the 46 has a different phase plug I'm not even that amazed about that happening.
Although the 2446 is more cleaner , so im now in the position where I change every week between them because I cant choose :)

[ivica]

I ment the inductors as you can see in one of the schematics in this post, 4313 made that network without the replacement inductors for the tapped transformer, I use the drivers as in these schematics as in this post,........


Hi Hans Bleeker,

Is it as in this post:
http://www.audioheritage.org/vbulletin/showthread.php?32358-4345-4355-networks&p=346533&viewfull=1#post346533

or something else

Regards
Ivica

[Hans Bleeker]

Hi Hans Bleeker,

Is it as in this post:
http://www.audioheritage.org/vbulletin/showthread.php?32358-4345-4355-networks&p=346533&viewfull=1#post346533

or something else

Regards
Ivica


Yep thats the what I call the coilless network, and in post #8 is the coiled version .
I'm curently at the point where I'm gone make that non coiled version again, I mis things in the dynamic range that 4313's filter did. I can't remember if I tried the 2446 / coated driver combo with that network. Its very easy to make the mistake after trying many different things to relate a problem to the wrong cause, So I need to know for sure.

[ivica]

Yep thats the what I call the coilless network, and in post #8 is the coiled version .
I'm curently at the point where I'm gone make that non coiled version again, I mis things in the dynamic range that 4313's filter did. I can't remember if I tried the 2446 / coated driver combo with that network. Its very easy to make the mistake after trying many different things to relate a problem to the wrong cause, So I need to know for sure.


Hi Hans Bleeker,

Thanks for your answer.
I have tried moving R18 just after C7, and putting 2.2uF "paralleled" with L6. That would produce steeper HF low-pass over 10kHz, lowering 2241 - 2405 comb filter effect.

Regards
Ivica

[Hans Bleeker]

Wel, the jury has reached a verdict :) 4313B is guilty of making the best of the two networks :)
What I did is use one network of each type at the same time, one left one right and listen to mono signal . Then it was quickly noticed what the difference is. Had I never heared that network I would have been totaly happy with the original replacement network.
The side with 4313's network instantly opened up a lot, its like the original network drives while the parking brake is still on.
The faint rough edge im talking about is in between the 2202 and the 2446, but that can easaly be the horn that i'm using, I like that horn a lot btw. Also it can be that sinds that network is more revealing it shows a shortcomming somewhere else in the chain that stays hidden with that parking brake on :)

Picture is what I use as test setup although I use it with the 2235 now, W15Gti was as start test version, I must say the W15 isnt as horrid as some people say here but it doesnt integrate as the 2235 does, logical in my opinion, Im thinking of letting it run in paralell with the 2235 till 100Hz , same way as the 4435 did, the low that W15 makes is stunning in that region (in a 225L enclosure).

[Dr.db]

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46834&stc=1&d=1280446056





http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46973&d=1281711970





The L-Pad board in the photo above was for the 4344 MkII network that I also tried. The compression driver has the 1.0 mH 7.5 ohm DCR coil across its terminals and the 2123H has the 3.5 mH 7.5 ohm DCR coil across its terminals as per Greg's schematic.




Sorry for discussing this old thread, but could you please verify:

The L-Pad board of the 3155 network looks different to this one, right?
I can`t see any of these 1.0mh & 3.5mh 7.5ohm DCR coils in the 3155 equivalent schematic, have I missed something ?

[Hans Bleeker]

The schematic above your question is the version 4313b made.
This is the GT version , the replacement network with coils instead of autoformers and no cc.

[Hans Bleeker]

O mixed up two things here , well you did, you are looking at the 4355 networks now, thats totaly different from the 4344,

This is the file containing the 4344 network.

[Dr.db]

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=69355&stc=1&d=1453152257

Is this schematic for 3155 or 4344 ?

[Hans Bleeker]

Thats the 3155 replacement filter from GT, I linked the 4344 in my previous post as pdf.

[Dr.db]

Thanks a lot for your help allready!!


I have a few questions to the GT-version;

- why is the 0,07mh coil in series with the 2405-slotdriver ?? (same for the 0,14mh coil in the midrange...)
- are there any L-Pads provided ?
- do these resistor-values adjust sensitity of the horndrivers with the 12" midcone driver without the L-Pads ?

I have to say this schematic looks quiet different to 4313b´s equivalent network!
I´m actually confused...
I thought 4313b just doubled capacitor values and quantity to charge couple them, but the actual value´s differ significant. I figured resistor values would be about the same in both schematics, but they are totally different :blink:

[Hans Bleeker]

Those coils in GT's network are the replacement values for the autoformers, they work in conjuction with the paralell ones,
4313b made an entire new network thats 4dB hotter . I have made both versions and both have their own magic, the Original from GT is more laid back, little bit but more holographic, 4313b is more open more life little less holographic and both have great soundstage..
And yes, the L-pads are in the usual spot, just not in the drawing.

[Dr.db]

Thanks a lot for your explanation of GT´s network! :)



http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46834&stc=1&d=1280446056





http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46973&d=1281711970





Sorry for discussing this old thread, but could you please verify:

The L-Pad board of the 3155 network looks different to this one, right?
I can`t see any of these 1.0mh & 3.5mh 7.5ohm DCR coils in the 3155 equivalent schematic, have I missed something ?



If I stick with 4313b´s version of the 3155, their are no such coils infront of the L-pads with 7.5ohm DCR, right ?

.

If I don`t want to charge couple, all I have to change is the capacitor values?
For example;
C11(2uf) and C9(2uf) become 1uf in total
and
C10(3,6uf) and C12(3,6uf) become 1,8uf in total...?

Or does anything else changes by this revision?

[Hans Bleeker]

That is correct, series C's have haf the capacaty, so 2x2 becomes 1 en 2 times 3.6 becomes 1.8.

I dont see where you found that coil with 7,5Ohm DCR, Dont see it in the schematic. And you need a serious amount of wire to get a coil to 7.5Dcr :)

[Dr.db]

I guess these 3,5mh and 1,0mh 7.5ohm DCR coils had been used in the 4344 just across the L-Pads.
See the foto I posted, there are two coils infront of the L-Pads.
I think I confound things as these seem to belong to the 4344 network instead of the 4355 network.

[martin2395]

7,5 ohm DCR on a coil would be quite unusual...wasn't it combined with a resistor placed in series?

[4313B]

Greg often used 1.0 mH and 3.5 mH air core inductors having 7.5 ohms DCR across midrange and high frequency transducers back in the 70's and 80's to mitigate their resonance frequencies. Note L3 and L4 below in the L212 parts list. These exact same L212 parts are shown above in my L-Pad board photo. Way back in the early 80's I purchased a bunch of each from JBL Parts.

It turns out that he also used them in the 4344 Mk II many years later sans the high DCR values, at that time he used resistors in series. L3 and L6 in the schematic.

[Odd]

7,5 ohm DCR on a coil would be quite unusual...wasn't it combined with a resistor placed in series?

Yes, read here (http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project) and here (http://www.audioheritage.org/vbulletin/showthread.php?29189-Am-I-building-these-correctly-JBL-4355-Crossovers).


Edit. Didn't see the post above before I posted.

[Hans Bleeker]

NVM, I should look at previous posts first :)

[Dr.db]

Greg often used 1.0 mH and 3.5 mH air core inductors having 7.5 ohms DCR across midrange and high frequency transducers back in the 70's and 80's to mitigate their resonance frequencies. Note L3 and L4 below in the L212 parts list. These exact same L212 parts are shown above in my L-Pad board photo. Way back in the early 80's I purchased a bunch of each from JBL Parts.

It turns out that he also used them in the 4344 Mk II many years later sans the high DCR values, at that time he used resistors in series. L3 and L6 in the schematic.

Thanks a lot for that clarification! :)

So these 7.5ohms DCR coils on your L-Pad board photo do not belong to the 3155 circuit at all, right?

[Odd]

Thanks a lot for that clarification! :)

So these 7.5ohms DCR coils on your L-Pad board photo do not belong to the 3155 circuit at all, right?

They are also used in 3155

[Hans Bleeker]

They are also used in 3155

Can you explain to me where they are used in the 3155, see attached schematic.

[Odd]

They are not used in the original 3155
I was referring to 3155 equivalent schematic in post 50

[Hans Bleeker]

In that schematic I dont see that coil with 7.5DCR or a combo Resistor - coil, what am I missing, I'm speaking schematic, I build that filter thats posted but not with a 7.5Ohm coil. Is there an assumption I should have known it should be there but without putting it in the schematic?

[Odd]

In that schematic I dont see that coil with 7.5DCR or a combo Resistor - coil, what am I missing, I'm speaking schematic, I build that filter thats posted but not with a 7.5Ohm coil. Is there an assumption I should have known it should be there but without putting it in the schematic?


You are right in terms of schematic.
Photo in post 50 and 57 shows DIY (http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project/page8) 4345 (http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project/page8) as "4313B" built it.
There they are.

[Hans Bleeker]

This is realy stupid, I never noticed those remarks about that coil resistor network , red all again starting from post 1, how could I mis that, might be the reason I have to turn my L-Pad almost to the closed position to get the 2"driver in balance, its way to loud . I wonder since its probably rounded of values, would an 6.8 ohm resistor and a 3.9mH coil do the job as well on the 2202 that is ofc? Thats the values sold in Europe. The larger coil value shifts the frequency only little bit lower, and the total DCR will be 6.95 together with the coil, I would say dampens a little bit more but hope it wont influence the rest of the design to much.

[martin2395]

Hi Hans,

You can order custom value coils through RumoH in the Netherlands, not sure about the DCR though.

[Odd]

1.0 mH and 3.5 mH air core inductors is fairly common values.

You can buy here (http://www.jantzen-audio.com/), and in many other stores.

For exact DCR put a resistor in series.

[Dr.db]

@ Odd:
Please don´t get me wrong, I don´t want to dubitate your statement but 4313B´s posting says this L-Pad board was used with the 4344 network. He had a seperate 4355 network...
I have read all your linked threads but I can´t find any posts saying their have to be 7,5 ohms coils in the 3155 equivalent network.




The L-Pad board in the photo above was for the 4344 MkII network that I also tried. The compression driver has the 1.0 mH 7.5 ohm DCR coil across its terminals and the 2123H has the 3.5 mH 7.5 ohm DCR coil across its terminals as per Greg's schematic.

Listening to the 4344 Mk II network side by side with the 4355 network I personally preferred the 4355 network, greater power and dynamics, which is what I expect from such a large loudspeaker.

[Odd]

The crossover will work just fine without, but better with.

[Dr.db]

Thanks for your patience! :)

[Dr.db]

Is their any guideline to follow in picking up the correct coils/inductors ?
I have no idea what DCR values I should aim for.

When using air-core coils I´d get a DCR of about 0,1ohms for the 0,16mh coil.
Is this to high or too low?

[fencki]

hi.
i hopefully may ask one question about making a crossover for 4345?
can i use the crossover showing in the picture for 4344 mk2 (original the drivers were very similar except the woofer) with my following drivers?

2245h
2123h
2420
2405

in the picture there is no LF (2245h).

what should i change?

i am new to crossover building and hopefully the questions are not too .....

:)

thx and best regards


74378

[fencki]

or maybe someone can tell me which crossover would be the best compromise?

[jjt]

Hi Guys,
For the equivalent 3155 network, what gauges are you guys using for the 4 inductors (2.4mH, 1.0mH, 0.47mH, and the 0.16mH)?
and
I guess you have to order these directly from Solen? I don't see anyone else carrying all the sizes. Do you guys use any other sources?

Thanks



> Hmm, forgot about that thread ( thanks Paul ) ~

> Here's the network from that thread ( maybe it's not final / it is missing the Lpads );

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46834&stc=1&d=1280446056

Some Voltage Drives ;

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=48213&stc=1&d=1288356468

Pic with Lpads in place ( showing impedance stabilizing coils ) ;



http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46973&d=1281711970



:)

[Mannermusic]

Hi Guys,
For the equivalent 3155 network, what gauges are you guys using for the 4 inductors (2.4mH, 1.0mH, 0.47mH, and the 0.16mH)?
and
I guess you have to order these directly from Solen? I don't see anyone else carrying all the sizes. Do you guys use any other sources?

Thanks

The approx. "rule of thumb" per JBL engr. lab is to keep R < .6 ohms. Size as needed. Parts Express in Dayton has a good site with multiple suppliers plus accompanying specs, etc. My guesstimate would be 15 or 16 ga for the 2.4, 18 ga for the 1.0 and 20 ga for the .47 and .16.

[fencki]

can u please explain what is meant by "ga" in your answer?

[Dr.db]

I think this revers to cable diameter...

[Odd]

AWG to mm conversion (http://www.rapidtables.com/calc/wire/awg-to-mm.htm)

[Mannermusic]

can u please explain what is meant by "ga" in your answer?

gauge - wire diameter. See post #83 (thanks Odd).