Cheap Chinese active X-O

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"HIFI Electronical 2 Way Crossover PCBA ClassA Power Linkwitz-Riley filter 4-Channel Output Crossover-point 2.2K Hz Free Shipping"

I've bought two of these with X-O points at 80 and 100hz for use with sub-woofers for my single driver MTLT systems.

Having frequencies down to a measured 30hz adds a subtle but valuable fullness to some music.

I used MathAudio's free plug in for FooBar to flatten out the peaks in my systems.

Anyway... Has anybody done testing on these $30 active X-Os?
Does the design look OK? 'Seems so inexpensive... less than passive X-Oers.

Thanks, Mack
 
It has input buffer but no output buffer by the looks of it, only 5 amps per ch.
I'd like to buy one at that price, but they don't take Paypal so no buyer protection, and there's no way I would give my credit card no to China.
 

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What the DIY audio store could perhaps use is a PCB /kit for simple, adjustable active 2-way line level XO for those folks not able to design their own, nor quite ready to take the leap to minidsp or such - something that could be piggy-backed with something like the B1 or Mesmerize line stage/ buffer, perhaps even in the same enclosure?

There are probably more than a few of us with sufficient amps kicking around, but from my own readings, the sonics of the minidsp's onboard DACs could easily be improved. However, for those of us not enthralled at the prospect of building the multiples of required channels of DACs, that means the expense and complication of at least 2 more little boxes and associated interconnects
 
Trouble is with this Chinese xover if the amps are not the same gain then you have no adjustment of volume over the highs or lows on this xover, so to get the balance right.
So it would have been nice to have a level control with output buffer after the highpass and low pass sections, to fine tune the balance between highs and lows. (just like the one I posted)

Cheers George
 
Trouble is with this Chinese xover if the amps are not the same gain then you have no adjustment of volume over the highs or lows on this xover, so to get the balance right.
So it would have been nice to have a level control with output buffer after the highpass and low pass sections, to fine tune the balance between highs and lows. (just like the one I posted)

Cheers George

Can't the individual amp vol controls do this?
 
the world is loaded with poweramps with volumecontrols:)

The majority of poweramps usually don't, at least the ones I've had in the last 40 years of hi end audio.
Sorry one did the 1976 Yamaha P2200 poweramp did, and it had a very good pot, an Alps Black Beauty, even better than the Blue Velvet, the amp was OK'ish good bass, mids and highs so so.

Why not just have a level trimpots on the xover like all active xover have, and then it will suit everyone.

Cheers George
 

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No money for hi end, that's why I hang around here.
For example almost all Parasound power amps has level or gain control. I prefer controls for safety reasons , an fully open power amp is to asking for trouble. Sooner or later somebody will disconnect or connect a cable and the bass diaphragm will fly across the room.
 
The most major problem I see with active crossovers (and maybe DSP) is now losing the clarity of the LDR preamp!!!!! (thanks again)

It would be great to have an active or passive crossover that doesn't compromise that. Something like the Boozhounds Jfet or simpler. JFET Crossover Kit – Boozhound Laboratories

What, if any, crossovers do you use for your Martin Logans, George. I want to go active on my Sequels (or DSP), but I am now worried about degrading the sound.
 
I use the passive 18db xover of the ML's to the ESL panels, but use (150hz) 24db active to the bass units. (Attached) (Also I use better opamps than the TLO74's)

I don't use the high pass of this circuit as it's not as transparent as the passive of the ML's.

Cheers George
 

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Here is the three way of the same active xover. Very well thought out, as you can see input and output buffers to keep all active xover components isolated from the outside world, with level pre-set trimpots before the output buffers.

http://archive.siliconchip.com.au/cms/A_30278/article.html
 

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