LX-mini Crossover Article

Dear all,

I'm ordering materials for the firstwatt asp at the moment.

I have a question about the firstwatt asp lxmini crossover.
my current configuration: 2x4HD minidsp -> preamp volume control -> power amp.
the new configuration: Meridian DAC -> firstwatt asp -> preamp volume control -> power amp.

When I read the documentation from Nelson I understand that the lowest distortion is reached by very low input/output voltage.
this means that the new configuration should be:
Meridian DAC -> preamp volume control -> firstwatt asp -> power amp.

My question is how do you use the asp crossover ?

would like to hear your reaction

Kind regards,
Gerard

Thanks for you reply.
The first document I all ready read, second is new for me.
It's obviously the preamp first then the ACN
The disadvantage to this configuration is the turn-on and turn-off thump, the output of my pre_amp is shorted if turn-on/turn-off.
 
Nelsons LXmini / LXmini+2 / LXstudio pcbs and matched JFETs will be available again by next week.
PCBs only available as well.

Cheers, Frank


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I need 1 set meassage me plz.
 
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I recently purchased a large number of 2SK170BL JFET's, I spent a couple of days measuring and matching them. I have enough matched pairs to change my B1 Korg to the K170's and now I'd like to change the buffers in the ACN I built.
In the LX mini-Crossover article, Nelson discusses the buffer circuit he designed for the Crossover using J113's. In the buffer circuit, the lower J113 is a current source with a bias resistor, the upper J113 is the buffer with a load resistor to lower distortion levels using the J113's.
The LX xover circuit has resistors R17 - R19 & R39 - R42 as the "load" resistors for the J113's. If I was to substitute the K170's for the J113's, do I delete the load resistors?
I plan on using the K170 matched pairs, one for the left channel and one for the right channel.
 

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Hello,
I have not been on the forum for a while also a novice at DIY audio. What led me to this forum was a web search on "Cube Audio F8 Magus Open Baffle and stumbled on to this Stereophile article which showed Nelson Pass's Open baffle design using his LXMini. I own a pair F8 Magus drivers and would very much would like to see if I can implement Nelsons open baffle design.
Has anyone else on this forum followed Nelson's footsteps using Cube Audio's magnificent drivers?
Thank you.
 

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I'm using the Active Crossover Network, which is the LX-Mini with a different crossover center point, the filter values I used were from Nelson's Speaker Camp last fall. The ACN goes to a Sony VFET P channel amp by Nelson and the Woofers are connected to an SIT 50W amp using TOKIN THF51s VFET's designed by Zen Mod. I only had this system in place for a month or so before converting back to Lowthers and a J2 clone amp I just finished.

I very much enjoyed the sound with the two amps, I would like to dial in the EQ of the ACN for the CUBE FC 8 full range drivers, Nelson used the EQ for the MOTH's FR drivers during the speaker camp. I'm not sure if there is a difference, I just want to learn how to measure speakers and make small adjustments, which I'll do after I've listened to the J2 for a while.
 
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What is your impression of the amps?
The VFET P channel amp is incredible with vinyl, my favorite is Chick Corea's 3 album set of solo piano, inspiring. Digital is a struggle, it's to bright, so why bother. The J2, has noticeable increase in mid-bass, this takes care of the Digital, this is a great all around amp. It plays everything, no loss of sound stage or top end accuracy, I'm enjoying the J2 clone. By far an easy amp to listen to.
Now I have to build a Balanced version of the LX-mini/ACN, I think this amp will do a great job with CUBE full range. Two boards stacked on top of each other will work to keep enclosure size to a minimum.
 
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