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INFINITY QUANTUM 2 - crossover - bi/tri/quad amping

K

KraftwrkTrbo

Active Member
The crossovers are a mess. Instead of just repairing/rebuilding/fixing, I would like to modify for bi-, tri- or even quad amping.

a) the Quantum 2 is known for being VERY amp hungry. Where does the low impedance occur? Is the woofer the cause? Or the drivers in conjunction with the low pass and low/mid band pass?

b) Can someone make the changes in the attached wiring diagram to show the mods for direct amping (looks like it is designed for bi amping already, so proper tri and quad amping mods)?

c) According to the data sheet: Crossover Frequencies: 200Hz, 600Hz, 4kHz. If tri amping, I would drive the mid/high dome and the EMT together (with a class A or tube), low mid with class A/B and bass with a class D. Infinity Quantum QLS-2 crossover.jpg
 
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yep thats a hack job, the one on the right is close to original other than the 2 binding posts on the right :)
 
Before hooking up for first test, did some measurements today: Measured resistance 'as wired": bottom 0, middle 0, top right 0. Removed wires: bottom 3, middle 20, top 8.
271834753_4649788741742600_7159195141322948306_n.jpg
 
Unless I 'm looking at the technical sheet wrong, if the crossovers are still using the factory components/wiring then you should be reading infinite resistance across each due to the series cap in each section. Unless you mean "0" as in open. Still, something is definitely wrong with the woofer section based on the schematic. Even if the crossover section for the woofers was removed and an external electronic crossover was used you should be reading just the V.C. dc resistance. Any chance on getting some pictures of the inside with the crossover?
 
0 means zero Ohm.
I will take a woofer out, see if that makes things more accessebile. Was hoping the entire crossover board than easily be removed from the backside like a plate amp.
 
KraftwrkTrbo said:
0 means zero Ohm.
I will take a woofer out, see if that makes things more accessebile. Was hoping the entire crossover board than easily be removed from the backside like a plate amp.
Click to expand...

Zero ohms would indicate a dead short. Not good for any amplifier connect to it. From what I can tell in the pictures the components appear to be correct and what Infinity was using at the time. That doesn't mean they aren't bad(failed). Hard to tell if the wiring is correct. It could have been messed with when the additional binding posts were added.
 
KraftwrkTrbo said:
Anyone know how to REMOVE the 2 boards from the enclosure?
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You have to work like a putty knife or something under it to get the silicone caulk free that holds it / seals it the the enclosure loose. It comes up fairly easy once started. Take the 4 screws out first.
 
The plastic board can be removed by just pushing it to inside (carefully), or trying to remove the stapes and then brake the 'glue'.
The wooden board is held by 6 philips wood screws to the floor.

Have not figured out how to get to the REAR EMIT tweeter behind the cloth fabric?
 
Tri amp….? Quad amp..? Seems like a lot just to run a set of mid fi speakers…

I would rather get a nice size amp with some good headroom…(handle 2 ohm drops) and be done with it….recap accordingly based on what series that is…some have bi amp feature and rear firing emit, some don’t…
 
Bkphoto said:
Tri amp….? Quad amp..? Seems like a lot just to run a set of mid fi speakers…

I would rather get a nice size amp with some good headroom…(handle 2 ohm drops) and be done with it….recap accordingly based on what series that is…some have bi amp feature and rear firing emit, some don’t…
Click to expand...
I plan for bi amp (amp with good headroom (low impediance capable) and nice amp for mid/highs).
 
Turns out I have ONE speaker with rear firing EMIT, one without. So from different 'generations'. Also assume one crossover was already done for bi amp (before PO messed it up), the other not. Serial numbers are: 1020782 (single) and 7102026 (bi amp, rear EMIT).
 
Ha! Those are the ones that were northwest of Detroit. I was going to have my brother go look at them for me and pick them up if nice.

I thought his asking price might've been ok in this inflated market, but those modded x-overs did make me hesitant...
 
Dirty Dan 3 said:
Ha! Those are the ones that were northwest of Detroit. I was going to have my brother go look at them for me and pick them up if nice.

I thought his asking price might've been ok in this inflated market, but those modded x-overs did make me hesitant...
Click to expand...
Well, I am now stuck with them. Took them completely apart, and rebuilding the x-over to original design (including proper bi wiring (thinking about tri wiring to drive the mid/high dome tweeters and EMITS seperate from the low/mid cone and certainly the 'two way' bass. Also needed better sealing. Not sure when I have them back together again.
I am in Brighton.
 
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