Vintage JBL 4700 Sound Power Series

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   About two weeks ago I purchased an old community Hall sound system from West London at a very cheap price because they needed the space ASAP.  The speakers were stored under the stage in a small store room.  I was told three drivers were not working but all were original stuff except the horns in the 4750's were upgraded 2446's

I believe the 4700 series was popular in the 90's.  I remember Butlin's in Bognor Regis had a system installed with the 4788 TCB's under the stage.  Im still yet to hear bass like those things produced.  So smooth, tight and deep low but certainly not overwhelming.

The stuff I bought consisted of the early 90's JBL 4700 series original Sound Power Series vintage stuff.  Real heavy thick ply cabs.

Two JBL 4750
Two JBL 4730
Two JBL 4785 TCB's

And a JBL crossover

I used to own a pair of the Triple Chamber Bandbass speakers many years ago. Very low smooth bass. 

I set out stripping to see whats blown.  Found two 2225's blown in one of the 4785's.  One of them was seized solid, no movement of cone.  The other had very bad voice call rub.  I shall replace with a pair of 2226's which I believe are a direct replacement that I have spare. The other 4785 were perfect.  All had the four rods inside and grills over the ports.  The grills normally get kicked out. 

The 4730's had one 2118h 8" mid open circuit with no ohm readings, also coil rub so I will recone it.  All the others including baby bums were spot on.  The 4730's are passive with three way crossovers. 

The 4750's had two 2206's in each which were fine, but one the 2446's compression drivers is open circuit.  Checked the diaphragms which seemed to be original genuine diaphragms. The one that was not working doesn't show any burn's.  I guess the windings is broken somewhere.  

TCB's with a pair of JBL Concert Series 4825's which I brought a few months ago. Horns are from 4750's

Dismantling for testing and refurbishment 

Edited by shaun1264 - 06 September 2013 at 1:06pm

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shaun1264 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: Surrey Status: Offline Points: 325	Post Options Post Reply Quote shaun1264 Report Post Thanks(0) Quote Reply Topic: Vintage JBL 4700 Sound Power Series Posted: 06 September 2013 at 12:42pm
	About two weeks ago I purchased an old community Hall sound system from West London at a very cheap price because they needed the space ASAP. The speakers were stored under the stage in a small store room. I was told three drivers were not working but all were original stuff except the horns in the 4750's were upgraded 2446's I believe the 4700 series was popular in the 90's. I remember Butlin's in Bognor Regis had a system installed with the 4788 TCB's under the stage. Im still yet to hear bass like those things produced. So smooth, tight and deep low but certainly not overwhelming. The stuff I bought consisted of the early 90's JBL 4700 series original Sound Power Series vintage stuff. Real heavy thick ply cabs. Two JBL 4750 Two JBL 4730 Two JBL 4785 TCB's And a JBL crossover I used to own a pair of the Triple Chamber Bandbass speakers many years ago. Very low smooth bass. I set out stripping to see whats blown. Found two 2225's blown in one of the 4785's. One of them was seized solid, no movement of cone. The other had very bad voice call rub. I shall replace with a pair of 2226's which I believe are a direct replacement that I have spare. The other 4785 were perfect. All had the four rods inside and grills over the ports. The grills normally get kicked out. The 4730's had one 2118h 8" mid open circuit with no ohm readings, also coil rub so I will recone it. All the others including baby bums were spot on. The 4730's are passive with three way crossovers. The 4750's had two 2206's in each which were fine, but one the 2446's compression drivers is open circuit. Checked the diaphragms which seemed to be original genuine diaphragms. The one that was not working doesn't show any burn's. I guess the windings is broken somewhere. TCB's with a pair of JBL Concert Series 4825's which I brought a few months ago. Horns are from 4750's Dismantling for testing and refurbishment Edited by shaun1264 - 06 September 2013 at 1:06pm

shaun1264 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: Surrey Status: Offline Points: 325	Post Options Post Reply Quote shaun1264 Report Post Thanks(0) Quote Reply Posted: 12 September 2013 at 6:39pm
	When I have some time, i'll start refurbishing. A good rub down and re-paint. Then get a local sign shop to reproduce the JBL side wall logos as they are one those things that are hard to track down.

oldskool Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 04 October 2010 Location: Essex Status: Offline Points: 2097	Post Options Post Reply Quote oldskool Report Post Thanks(0) Quote Reply Posted: 12 September 2013 at 6:49pm
	Nice job you have there. I have 8 sound power cabs to refurb once the main system is done and will need 16 of those logos too, or a decent stencil.
	Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong remedies

shaun1264 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: Surrey Status: Offline Points: 325	Post Options Post Reply Quote shaun1264 Report Post Thanks(0) Quote Reply Posted: 12 September 2013 at 7:21pm
	Thanks, was a bargain price too. I was lucky to find all original drivers. No silly any old driver replacement. I'd like to eventually find one more pair of JBL 2404 baby bums to install in the 4750's. I have one pair spare ready to go in, just need another. They will replace the blanking plates in the 4750's. There was a very nice refurbished pair of 4755's on eBay that sold for £600. I asked the man how he reproduced the logos on the side walls and he said a local sign company did it, so thats the route i'll go down.

mk2_ginger_biscuit69 Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 03 November 2008 Location: Brighton Status: Offline Points: 7797	Post Options Post Reply Quote mk2_ginger_biscuit69 Report Post Thanks(0) Quote Reply Posted: 18 September 2013 at 12:09pm
	hairdressers landrover.... for shame is there any rough internals of those TCB subs, and spec's with original drivers? Seen them floating around all over the place, heard they are meant to be pretty nice also. Cheers
	''Remember that the object of a subwoofer is to enhance the output of your main speakers, not overpower it'' ''Dubstep - an elongated electronic fart''

djeddie Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 26 April 2004 Location: Bristol Status: Offline Points: 4125	Post Options Post Reply Quote djeddie Report Post Thanks(0) Quote Reply Posted: 18 September 2013 at 8:45pm
	I'm sure the TCB plans were shown on the forum a couple of years ago Pat. They're not bad but... their delay is measured in weeks rather than milliseconds! I did an install a couple of years ago in an indoor paint-ball place playing 'war sound effects' and they certainly made everything shake including the stock in a warehouse up the road.
	Chas n Dave : it's like Drum and Bass but with beards. E=mc² ±3dB

shaun1264 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: Surrey Status: Offline Points: 325	Post Options Post Reply Quote shaun1264 Report Post Thanks(0) Quote Reply Posted: 19 September 2013 at 6:28pm
	JBL made three different variants of the 15'' loaded TCB subs: http://www.jblpro.com/pub/obsolete/4685.pdf The original and first produced version. Loaded with 2225. http://www.jblproservice.com/pdf/Sound%20Power%204700%20Series/4785A.pdf Different cabinet dimensions, 100 dB sensitivity, loaded with 2225 http://translate.google.co.uk/translate?hl=en&sl=ja&u=http://audio-heritage.jp/JBL/speaker/4785a.html&prev=/search%3Fq%3Djbl%2B4785a%26client%3Dsafari%26rls%3Den%26biw%3D1199%26bih%3D1249 Slightly different size cabinets, again loaded with 2225 but higher sensitivity and with different freq response. Goes down lower. The 18'' version which JBL made three different variants are true beasts. Edited by shaun1264 - 19 September 2013 at 6:38pm

KonanSS Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 17 August 2011 Location: Devon Status: Offline Points: 392	Post Options Post Reply Quote KonanSS Report Post Thanks(0) Quote Reply Posted: 21 September 2013 at 11:01pm
	Hahaha yes! Perfect thread for me, I have a pair of jbl 4788a subs. Le those but with bigger ports, here's the spec sheet. Exept I loaded mine with b&c 18sw115, bow powered by a matrix class a/b xt10000mf, sounds incredible, haha these CBS get hate but I cannot find another cab that does 25hz comfortably,with such power and holds it like a beast! http://www.jblproservice.com/pdf/Sound%20Power%204700%20Series/4788A.pdf I'll put pictures up when I know how! They made literally so many of these subs, not sure if allot of them were just tests but I have seen too many! And there all different, still have yet to see a model that comes close to mine. But hey, I was going to replace them with other subs but they have the best acoustic responce I think I've ever heard out of a sub. :) Edited by KonanSS - 21 September 2013 at 11:03pm
	KSS - Devon based always wanting to learn more

fat_brstd Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 23 August 2008 Location: Melbourne, OZ Status: Offline Points: 2184	Post Options Post Reply Quote fat_brstd Report Post Thanks(0) Quote Reply Posted: 24 September 2013 at 2:07am
	Hey mate, can you let me know where abouts you are getting your paint from for this refurb? trying to find a tub or 2 of martin grey
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luton_soundman Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 03 August 2010 Location: Bedfordshire Status: Offline Points: 4550	Post Options Post Reply Quote luton_soundman Report Post Thanks(0) Quote Reply Posted: 24 September 2013 at 2:27am
	Nice find. Was trying to get hold of those tops for quite some time

shaun1264 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: Surrey Status: Offline Points: 325	Post Options Post Reply Quote shaun1264 Report Post Thanks(0) Quote Reply Posted: 24 September 2013 at 5:53pm
	Hi, If you mean the Concert Series 4825's, I bought these from a guy in Chichester, West Sussex in the summer. Got the pair for under £200 so was quite happy with them. They are in near perfect condition with original drivers. He couldn't understand why the compression drivers were louder than the woofers when he was trying to drive them in a passive mode. lol Luckily the compression driver have a capacitor across them to protect them. They still have the original ITC8 Cannon sockets. (so hard to find the connectors these days!) i've got speakon plates to fit instead. There was a load of these 4825's complete with flightcases that sold earlier in the year in Manchester. The other speakers I bought are from a Community Centre. Two of us had to lift them above our heads to get them out of a store room! Im not sure of the paint colour yet, it looks like it's a slate grey. Just trying to source one more JBL 2225 woofer and a pair of 2204's.

ollie80 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 10 December 2012 Location: KENT Status: Offline Points: 117	Post Options Post Reply Quote ollie80 Report Post Thanks(0) Quote Reply Posted: 26 September 2013 at 4:59pm
	I remember these speakers. Early 90s and yes Butlins used them. Still like the old JBL stuff. Far better looking than todays cabs. Look much more mighty back then! Ollie
	Ollie K Nothing is impossible, the word itself says 'I'm possible'