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MX3000A input board?

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Greg32 View Drop Down
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    Posted: 17 October 2019 at 4:00am
Hi i have 2 mx3000a amplifiers, i have recapped both and they sound great, my question is regarding the input boards on both of them, there are a number of jumpers on them and i cant find any info online regarding these jumpers, I assume they are filters but would like any information. cheers Greg
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Djdarch Quote  Post ReplyReply Direct Link To This Post Posted: 17 October 2019 at 1:14pm
ive a load of JBL MPA input cards somewhere , does the MX3000a have the empty slot ready to accept a crossover card ? or is that the EX ? I think the EX was the same as the JBL MPA and the MX was the same as the MPX .I'll see if I can find the info I have about the crossover cards for the JBL version.

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Greg32 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg32 Quote  Post ReplyReply Direct Link To This Post Posted: 17 October 2019 at 1:50pm
Thanks, I will have to check tomorrow ,but I think it does have a slot for xover etc.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg32 Quote  Post ReplyReply Direct Link To This Post Posted: 22 October 2019 at 11:29am
This is the best pic I have of the input board.
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Elliot Thompson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 22 October 2019 at 3:36pm

Since the QSC EX 4000 was the original and, everything else after was a step-down version of the QSC EX 4000 in terms of power and features, you are going to find things on the PC Board that was not implemented in the later models.

 

I don't recall if the input modules made it past 1990 (QSC EX 4000 came about around 1987) when the MX 3000a was introduced around 1994. By the time the QSC MX 3000a was introduced, QSC's main focus was their new Powerlight Series.

 

The input modules were similar to Crown's PIP cards as, the EX Series was QSC's answer to the Crown Macro-Tech Series.The input modules stemmed from the 1980's which is around a decade before the MX 3000a was introduced to the market.

 

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Elliot Thompson
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg32 Quote  Post ReplyReply Direct Link To This Post Posted: 23 October 2019 at 8:36am
Thank you Elliot, that's an interesting time line break down. I've just checked my other mx3000 and it does not have the extra card with the jumpers. Seems I will have to try some REW measurements to determine the filters. 
Was there any limiting on the qsc mx amps? Thanks Greg 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 23 October 2019 at 11:49am
Originally posted by Greg32 Greg32 wrote:

Thank you Elliot, that's an interesting time line break down. I've just checked my other mx3000 and it does not have the extra card with the jumpers. Seems I will have to try some REW measurements to determine the filters. 
Was there any limiting on the qsc mx amps? Thanks Greg 


As with the QSC EX 4000, the QSC MX 3000a offers a fixed (You cannot disable) Limiter. The first generation MX (No "a" at the end) Series which was released in the mid 1980's did not offer any limiters. There is a significant difference on how the first generation MX looked compared to the second generation MXa once you take a glance at the faceplate. Internally, the MX Series and MXa Series differ great as well.

 

There are no additional filters on the QSC MX 3000a other than the internal fixed High Pass and Low Pass filters. If I recall correctly, the High Pass Filter is -3 dB @ 8 Hertz. User controllable High Pass Filters (30 Hz or 50 Hz) in addition to enabling/disabling the Limiter arrived later when, QSC reintroduced the QSC MX 3000a as the RMX 4050 HD.

 

The RMX 5050 stems from the RMX 4050 HD with larger power supply...

 

The design topology has been in production for nearly four decades with a few minor adjustments throughout the years. It is a very reliable design which matters the most in our industry. My EX 4000 amplifiers are still being used to this day and have never been serviced. I would imagine the RMX Series will be the last run of this design as, powered speakers are selling faster than stand alone amplifiers from QSC.

 

Best Regards,



Edited by Elliot Thompson - 23 October 2019 at 11:51am
Elliot Thompson
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg32 Quote  Post ReplyReply Direct Link To This Post Posted: 27 October 2019 at 8:14am
Well after a bit more digging the internet i was able to determine that the input board above is actually a limiter board, its called an SPL-1 stereo power limiter, ive found a flier for it but no info on settings. uploads/417/3253-SPL1SpecSheet_QSC_SPL-1_limiter.pdf
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 27 October 2019 at 8:41am
Originally posted by Greg32 Greg32 wrote:

Well after a bit more digging the internet i was able to determine that the input board above is actually a limiter board, its called an SPL-1 stereo power limiter, ive found a flier for it but no info on settings. uploads/417/3253-SPL1SpecSheet_QSC_SPL-1_limiter.pdf


Just contact QSC.

Best Regards,
Elliot Thompson
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