View Full Version : JBL/Crown amp module question

03-24-2014, 12:37 PM
Just hypothetically are any of these modules re programmable. The reason I ask is that there were a pair of 4892 Array's on e bay here yesterday. I was urging a musician friend to have a punt on them , he should have as they went for 216 for the pair.
In presentable condition to boot.
Anyway he has had Mackie SRM450's for the last ten years but they are now toast , but he is wedded to the integrated amp concept.
I was advocating a small rack with QSC's and a controller ( Berry prob ) but he seemed not too keen on this so on looking around I see that Speaker Repair in Tampa are selling complete amp modules for what seems reasonable $$.


Anyone have any experience with these modules ? Can you tweak them or is all the relevant data embedded and thats it ?

Just curious


03-25-2014, 10:19 AM
Just thinking aloud here , if these modules can be re programmed then it opens up possibilities for poor mans M? systems for cheap and cheerful money.
Surely there is access to the DSP module in the case that the pre set dumps for whatever reason ??
Anyone have access to a circuit diagram ?


Don C
03-26-2014, 07:28 AM
I don't see any connections that one could use to communicate with this except for the audio connections, so I'd presume that there is no way to re-program them. Maybe the service manual would show a service connection inside the box.

03-26-2014, 07:37 AM
There are a couple of pics on the web of the innards. Not power amps as we would know them !! No openly visible interfaces , do the semiconductor mfgs do non volatile memories in DSP packages ??.

03-26-2014, 12:51 PM
These modules are a standard frame with 1 to 3 amplifier sections possible. Of course to change the crossover parameters you would need to reprogram or replace the ROM and that info is held to the vest by harman ( JBL + CROWN ). The HF amp is a small chip amp and would not be powerful enough for the 2450SL driver

Also the 4892 ( I have a number of them) has larger components - most notably full 4" coils in the woofer and driver and there are a few CD comps and LF filters that are needed.

The much larger "ampmod" in the touring systems ( VT4882 ) have more powerful amplifiers ( again up to 3 channels ) and THEY have replaceable cards for each section. Note the 3 cards in the top of the chassis. They are called modulators and are quite involved but I don't see any digital components or DSP's on them.

..still waiting to find service info for this one here so I can prototype..:)


03-26-2014, 01:30 PM
Thanks Sub , I was just musing and hypothesizing and in any case the 4892's are gone from the reckoning. Boy he missed a bargain there , should have listened to uncle mac !!

I figured that these modules would be standardized modules , now I'm even more curious as to how the parameters are loaded in.

Good call on the Vertec modules , of course these will be much more spendy.

If the man concerned had listened I could have had him up and running for about a grand and sounding loads better than the K12's or whatever he will do for. Oh well.