---  Description   ---   Supplies  ---  FAQ  ---  Photos/Comments  ---   ---  Baffle assembly  ---  DSP challenge  ---

Supplies for LX521 construction and system assembly

The LX521 was designed for easy DIY construction and without sacrifice to acoustic performance. It is important not to change the baffle contours, the frequency response of the ASP, or the passive crossover. If you want to experiment or have ideas about improving my design, then I recommend that you first build and listen to the LX521 having followed the instructions in the Construction Plans. Support of the LX521 loudspeakers is provided via a web page to which owners of the LX521 Construction Plans have access. Additional construction and test information, revisions and updates are posted on that page. Check it out before you start building.

When building the speaker you will need to have some woodworking capability or find a cabinet maker. At  minimum a circular saw and a saber saw are required, but not a router. For the crossover you must load and solder components onto a printed circuit board, and connect wires where indicated. The finished assembly must to be tested electrically to avoid using the costly drivers as fault indicators. A digital voltmeter, AA-cell batteries and CD player are sufficient for spot checks. Acoustic measurements are not necessary.

Construction Plans

The 34 pages of the LX521 Construction Plans contain:

• Drawings for all baffle parts 
• Mechanical assembly instructions
• Driver and crossover wiring instructions
• ASP crossover/equalizer circuit description and diagram
• Material list for electrical components
• Loading chart for printed circuit boards
• Electrical assembly instructions
• Electrical test instructions
• System turn-on and test
• URL of the LX521 Owner Support Page

The LX521 Construction Plans are the license to build the loudspeakers for personal use. They are also required when subassemblies are purchased from other suppliers.

Cost of materials Construction Plans .................................................... $150 4 Tweeters, 4 Midranges, 4 Woofers ....................  $1600 Wiring, connectors, passive xo, speaker cables ..  $200 Wood, screws, glue, paint .......................................  $200     ASP components, pcb's, case, power supply ......  $700 ----------------------------------------------------  Subtotal   $2850 8x 60W or 6x180W Power amplifier .....................  $1835 ---------------------------------------------------------- Total   $4685

Blank Printed Circuit Boards for the ASP

Printed circuit boards are essential for assembling the Analog Signal Processor electronics. The ASP divides the incoming left and right channel audio signals into woofer, midrange and tweeter channels for driving the power amplifiers of left and right loudspeakers.
The LX521 ASP is assembled on the most recent ORION ASP printed circuit board. It supports balanced and unbalanced inputs. Tweeter, midrange and two woofer output connectors are unbalanced. Outputs can be attenuated to match power amplifier voltage gains if they are not identical. Silk screened component outlines and numbers on the pcb simplify loading the board. The board material is FR4 with two layers of 1 oz copper, has plated through holes, top and bottom solder mask and top silk screen. It is 0.062" thick and measures 7.6" x 7". This industrial strength circuit board makes for easy soldering of components. A praxis session is strongly recommended in order to learn temperature and timing to get to wet and shiny looking solder joints. Cold solder joints, solder bridges or burnt pads and damaged components can turn into a nightmare when trouble-shooting a dysfunctional circuit. Two boards are required for the ASP.  

Power Amplifiers

The AT6012 is rated at 60 W per channel into 8 ohm FTC full bandwidth output power, with all 12 channels driven simultaneously. The power supply has high current reserve and a 2000 VA transformer. Two LX521 speakers utilize 8 amplifiers, which leaves 4 amplifiers for any future use or driving lower midrange and upper midrange separately. The actual power output of the individual amplifiers is more than sufficient for midranges and tweeters. A separate amplifier channel is allocated to each of the 10" woofer drivers to obtain output capability that is commensurate with the midrange, yet minimizes bottoming and the risk of mechanical damage to the woofers, or having to reduce the speaker's low frequency extension. At very high sound levels the amplifiers clip first, which gives a clearly audible warning to turn down the volume. 

The AT1806 is a six channel power amplifier rated at 180 W per channel. If the two 10" drivers in the woofer baffle are connected in parallel, then they present a low 2 ohm impedance to the power amplifier around 100 Hz. The power amplifier driving this load must be capable of at least 200 W into 4 ohm.  The AT1806 is capable of producing higher bass output volume from the LX521 than the AT6012. The ASP crossover/equalizer requires no modification for its use. On typical program material the voltage swing to drive the lower-mid/upper-mid passive crossover is larger than for the woofers. Thus the AT1806 has more reserves than the AT6012 to handle extreme loudness peaks.
But, the higher power amplifier has the potential to bottom out and damage the woofers below 40 Hz and to overheat or stress midrange and tweeter with high level test or transient signals. I never had a failure with program material even at extreme volume levels.

ATI making an amplifier -- ATI sales story

Drivers, Wood Flat-pack & assembled ASP

Buyers of cabinet kits or assembled pcb's must own LX521 Construction Plans ($150). See below for ordering, shipment cost and payment.

Shipment 

1. LX521 Construction Plans and ASP printed circuit boards are shipped from LINKWITZ LAB via US Postal Service Priority Mail. 
2. Power amplifiers are shipped directly from the ATI factory.  A shipment charge for the continental United States is included in the quoted price. Overseas and International shipments cost extra. 

Payment options

You can pay with credit card over the Internet by using PayPal. In that case, please add a 3% payment fee (4% international) to the total cost of Kit and shipping. My address for PayPal is:  sl@linkwitzlab.com .

Alternatively you can purchase and send me a Postal Money Order, International Money Order, Western Union or Thomas Cook Money Order, or a Bank (cashier's) Check drawn in $USA currency and made out to Siegfried Linkwitz. I will wait with shipment against a personal check from a US bank until my bank has cleared it. A direct transfer of money from your bank to my bank account is not feasible due to unpredictable additional fees.

Send your payment to:

LINKWITZ LAB
15 Prospect Lane
Corte Madera, CA 94925
USA
sl@linkwitzlab.com (for PayPal)

Ordering information 

Send an e-mail message with the subject "LX521 order" to tell me the details of your order and to provide me with shipping information.
Copy the example below into an e-mail message to sl@linkwitzlab.com and edit the underlined text . 
(Drag your mouse over the text to highlight it, then COPY and PASTE into your e-mail message)

 

Shipping Label: John-Alexander Smith 345 Kensington Street Apartment #54 New York, NY 10019 USA Ordered items: (1) - LX521 Construction Plans ($150):   1 (2) - ORION ASP printed circuit board* ($75 each):    2       (3) - AT6012 power amplifier ($1835):**    0  (4) - AT1806 power amplifier ($1835):**    1 ** The price of the amplifier will increase on June 1, 2013 to $1950 plus shipping. Subtotal    $2135.00 California residents add 9% Sales Tax to the Subtotal Shipment cost of Construction Plans including up to 4 printed circuit boards:   US:  $10  International:  $25 Shipment cost of Power Amplifiers:  Continental US:   $0 International:  +$250 typically for Europe and 220VAC version. Inquire about exact shipment cost first.   Shipment total    $10.00 Total order    $2145.00 PayPal fees (3% US, 4% international)    $64.35 PayPal / Money Order in the amount of:  $2209.35 was sent on 25 October 2012 . Note: All material is copyrighted and for the personal, non-commercial use by the person who bought it from LINKWITZ LAB. It may not be passed on in any form for use by others. | Terms & Conditions | Comments:  Anything you want to tell me

* DIY construction of the LX521 ASP should only be undertaken, if you have some expertise in electronic assembly, test, measurement and component selection. Even with the detailed material list you may still have to procure substitute electronic components due to changing inventory of vendors. I provide an updated Support Page with the Documentation but cannot help you individually. The ORION/PLUTO Users Group has been very helpful in solving problems and answering questions.

*******************************************************************************************************************************************************

Send me an email to make an appointment for listening, talk or consultation about the LX521. The first hour is free. After that it costs you $150 for LX521 Construction Plans or ASP circuit boards. I live 8 miles north of San Francisco's Golden Gate Bridge in Corte Madera, California. Have fun!

I do not consult via email. 

******************************************************************************************************************************************************