Modified Crown 5000VZ - Help!!
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Category: General
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=98875
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Topic: Modified Crown 5000VZ - Help!!
Posted By: pczjm
Subject: Modified Crown 5000VZ - Help!!
Date Posted: 11 July 2017 at 10:17pm
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Hi Guys, I have a Crown Macro-Tech 5000VZ that was previously used as an amplifier for an NMR machine (similar to MRI) in the chemistry department where I work. It has apparently been modified to some extent for this purpose. The obvious thing is that the gain pots have been removed from the front but other than this I am clueless as to how it may have been modified. I popped the top, but never having studied the internals of an amplifier before, this was less than illuminating! There was no obvious/major difference to the pictures I found on the internet of the same model. Does anyone out there have experience of this kinda thing? As you might of guessed I wanna use it to power bass bins but am sure if I would need to "convert it back" to any extent. |
Replies:
Posted By: pczjm
Date Posted: 11 July 2017 at 10:24pm
Here's some pics: |
Posted By: pczjm
Date Posted: 11 July 2017 at 10:26pm
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Posted By: Dub Specialist Sound
Date Posted: 11 July 2017 at 10:53pm
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You need to get in touch with DjLeco forum member on here, ent seen him for quite a while tho hes a don with them, and amps in general ------------- Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE... |
Posted By: kedwardsleisure
Date Posted: 11 July 2017 at 11:14pm
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the front pots are connected to the rear board via a pair of screened grey cables, they fit at the back on either a 3 or 4 pin header depending on age. For the amp to work, there may be a jumper, resistor or preset pot fitted on these headers instead. Take a close up picture of the rear board if you're not sure and post it here. ------------- Kevin North Staffordshire |
Posted By: kedwardsleisure
Date Posted: 11 July 2017 at 11:18pm
ok, found a suitable pic. ------------- Kevin North Staffordshire |
Posted By: pczjm
Date Posted: 11 July 2017 at 11:41pm
Thanks for the replies!! I'll have a proper look tomorrow at work but the best pic I've got atm is this one, I can't see the grey cables! |
Posted By: DjLeco
Date Posted: 12 July 2017 at 12:01am
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Please give me the pictures at original size on mail claudiu971@ yahoo(dot)com On last picture, I see no gray cables for volume potentiometer(s), is missing, maybe potentiometers too. Make one as mr. kedwardsleisure put above, to see exactly if missing or not potentiometers and cables with connector too.
------------- I'm A Stupid SMART Romanian... |
Posted By: pczjm
Date Posted: 12 July 2017 at 10:18am
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Hi Guys, Thanks very much, hope this photo is better:  |
Posted By: studio45
Date Posted: 12 July 2017 at 3:35pm
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It's likely the modification involves DC coupling the output stage, the NMR machine would have required very low-frequency high-current signals with DC components to drive large electromagnet coils. I remember using them as an undergrad to determine the structures of molecules, they are eldritch high magick indeed ;) This will probably mean the speaker protection circuitry has been modified or disabled, because in normal audio operation any DC at the output is a fault. There was an industrial version of this amp (branded Amcron not Crown) that had a switch to select DC coupled or AC coupled (audio) mode. That may indicate that the modification is quite trivial. I see a wire link installed where one of the volume pots was connected. I would hazard a guess that the amp is in parallel-mono or bridge mode with the gain fixed at maximum (in those modes the channel B gain pot does nothing, so wouldn't need to be connected at all). I also see an extra trim pot tacked onto the legs of an IC and held in place with hot glue, and a capacitor added in series with a resistor, those do not look like factory installations to me.... ------------- Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA |
Posted By: DjLeco
Date Posted: 12 July 2017 at 4:09pm
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You must redo to factory construction all those modifications. ------------- I'm A Stupid SMART Romanian... |
Posted By: kedwardsleisure
Date Posted: 12 July 2017 at 4:51pm
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Looks like some of the capacitors have been linked out too. This could be serious! Oh and the optical compression components are missing ------------- Kevin North Staffordshire |
Posted By: M4trix
Date Posted: 12 July 2017 at 7:55pm
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That's easy. Just click on --> Macrotech 5000 --> Tools --> Settings --> Restore default factory settings --> Reboot Just joking.   |
Posted By: slim_dj
Date Posted: 06 December 2017 at 6:51pm
 Ive got a 5000 with same thing. No volume pots on front and only mod i can seem to see is those wires soldered to the IC. Did anyone have any luck with this? ------------- Quest Sound Systems |
Posted By: pczjm
Date Posted: 07 December 2017 at 10:23am
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Hi Mate, Found someone who has experience of these mods. Will be taking him my three amps at some stage soon. PM me if you want details. Cheers, Johnny
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Posted By: kedwardsleisure
Date Posted: 07 December 2017 at 10:42am
Yes slim yours is the same as the other ones. All the compression & limiting circuit components have been removed just apparent from the photo. ------------- Kevin North Staffordshire |
Ive got a 5000 with same thingPosted By: kedwardsleisure
Date Posted: 07 December 2017 at 10:47am
 ------------- Kevin North Staffordshire |