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THOR Construction Plans+

The plans provide detailed information for building and integrating THOR subwoofers with the ORION. These subwoofers will NOT extend the low frequency response of ORION. They will only add deep bass output VOLUME capability. The word 'subwoofer' is not the right descriptor since it acts like a 'substitute woofer'. The THOR units may also excite unfavorable room mode resonances depending upon their placement. THORs can have their application if you try to listen at realistic volume levels to organ music, or to sound effects from the movie LFE track. Thus I recommend to listen to ORION first and establish that you really need to add THOR to be satisfied with the maximum bass volume capability of the ORION System. Note that the ORION xo/eq has a 30 Hz, -6 dB/oct low-cut switch on its front panel, which reduces subsonic woofer cone displacements and effectively increases bass output capability when engaged. (See your ORION Owner Support Page) THOR can be added later and does not require any changes to an existing ORION System. 

The THOR plans also serve as an example on how to correctly integrate subwoofers with existing loudspeakers. The places where the electronics need to be customized, and how to go about it, are clearly marked in the circuit description.

This is a simple project and can be a good learning experience for working with line level crossover filters and equalization.

For budgetary purposes consider that the total material cost for two THOR units, including tax and shipping, is approximately $970. Adding the power amplifiers will increase this to $1720. Building a set of woofers takes about 20 hours of your time. 

Woofers can be built with different drivers and in different size cabinets, but then it is not a THOR. Please do not ask me for free advice about modifying the THOR. Use the documentation as a guide and study the extensive background information in the THOR pages of the website Archive CD . Then try on your own. Let me know when you find something of significance.

 

Example of an assembled THOR/ORION crossover/equalizer. A DIN cable is used to connect to the +/-12 V supply on the ORION xo/eq.

Example of finished THOR cabinets with mounted drivers.

From LINKWITZ LAB you can order:

THOR Construction Plans+ consist of 19 pages of documentation and two w-ASP circuit boards for adding THOR to the ORION. 

Each channel of the assembled THOR/ORION  xo/eq comes wired for driving a single power amplifier and for driving two power amplifiers in push-pull as when used with the AT6012. To obtain correct voltage levels for the two push-pull outputs of the xo/eq it will be necessary to clip off the leads of the jumper resistor that is mounted over R75. 
It is intended that the xo/eq will receive +/-12 V via the supplied DIN cable from the ORION xo/eq.

The AT1802 is a 180 W per channel stereo power amplifier. 
If you own the 12-channel AT6012 power amplifier for driving ORION, then its 4 unused amplifiers can be configured from the w-ASP for bridged mode operation to provide power to left and right THOR. No additional power amplifiers are needed.
The Peerless XLS 830500 woofer driver is no longer available. Its replacement is the Peerless XXLS 835017. 
The new driver has 4 ohm impedance and cannot be safely driven from bridged AT6012 power amplifiers. 
It requires a separate power amplifier like the AT1802.

Shipment 

The THOR Construction Plans+ are shipped via US Postal Service Priority Mail. Include $10 for domestic or international orders. Quoted delivery is 3 - 5 working days.
The AT1802 power amplifier is shipped directly from the factory to any location within the continental United States without additional charge. International shipment may not make sense because of the high shipping cost involved (>$100).

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.

Mail to:

LINKWITZ LAB 
15 Prospect Lane
Corte Madera, CA 94925-1617
USA

Ordering information 

Send an e-mail message with the subject "THOR order" to tell me the details of your order and to provide me with shipping information.
Copy the example below between the dashed lines into an e-mail message to sl@linkwitzlab.com and correct 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:

THOR Construction Plans+ 
        Project documentation ($60):   1
        (including Customer Support URL)
        (two) w-ASP pcb ($100):    0  

DIY construction of the THOR crossover/equalizer should only be undertaken, if you have some expertise in electronic assembly, test, measurement and component selection. You may have to procure substitute electronic components due to changing inventory of vendors. Some capacitor leads may have to be bent or lengthened to fit the hole pattern on the pcb. 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.

AT1802 power amplifier ($840):    1 

Archive CD ($25):    0

Subtotal:    $1615

California residents add 9% Sales Tax

Shipment of: 
Project documentation including printed circuit boards ($10 US and $15 international for up to 6 pcb)
AT1802 power amplifier ($0 continental US, around $100 international for 220VAC version. Inquire about exact shipment cost first.) 

Shipments:    $35

Total:    $1650

PayPal fees (3% US, 4% international):    $49.50 

PayPal / Money Order in the amount of:  $1699.50
Sent on 10 October 2010 .

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
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| Introduction | Estimates | Design | Measurement | Equalization | THOR-ORION xo |
| Supplies | SPL limits |