THOR support

Here you will find updates and new information for building your THOR woofers and for obtaining the best performance from them.

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(10)  10/20/09  12" driver replacement

The Peerless XLS 830500 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.

In the subwoofer ASP make R75 = 0 ohm and use the J3 +Sub output.
The equalization in the U5 stages no longer produces a flat acoustic response, but gives a slight boost towards lower frequencies and an overall increase in output level below the 50 Hz crossover frequency. This increase is compensated by adjusting the potentiometer R10 for a lower subwoofer output level than would have been used for the XLS 830500.

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(9)  9/2/09  ORION/PLUTO Users Group log-in

Now that you are a THOR owner/builder you can request access to the locked areas of the forum.

Sign in with your email and a password at https://oplug-support.org/index.php . You will be refused access but you can send an email to the Board Administrator (orionusers@gmail.com) from there and request to be admitted as an owner.

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(8)  7/24/07 THOR Material List

The new DigiKey part number for the 10kohm trimmer potentiometer is  3362P-1-103LF-ND

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(7)  5/3/07  w-ASP with 50 Hz crossover

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(6)  12/21/06  THOR Construction Kit (Rev. 11/30/06) and Supplement (Rev. 11/14/06) for 50 Hz crossover frequency 

Parallel capacitors C48 and C49-50.

When loading C48 = 1.5uF and C49-50 = 1uF make sure that the 1uF capacitor is inserted into the C49+ and C50+ holes so that it is electrically in parallel with C48 and the two capacitors add to 2.5uF.

Updated material list: 4-1 Orion-subw3-50xo.xls

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(5)  10/28/06  Supplement to the THOR Construction Kit for w-ASP (Rev. 8/25/06) for 40 Hz crossover frequency

C66 = 330nF (P3334-ND, quantity 2) is missing from the material list Orion-subw3-40xo.xls, 8/25/06.

The effect of this omission is that the Thor output is 2.2 dB too low at 20 Hz and 3.4 dB too high at 100 Hz, or missing about 6 dB of boost from 100 Hz to 20 Hz. Since this is strongly moderated by the 40 Hz crossover it may go unnoticed.

Adding the 330 nF capacitor to the circuit will lower the gain in the crossover region by about 6 dB and require that the woofer gain adjustment potentiometer be set close to its maximum. This may not be sufficient gain in some speaker setups and therefore R75 should be changed to a 0 ohm jumper, which increases the gain by 6 dB. 

Now the woofer channel has adequate gain adjustment range for push-pull drive of two AT6012 amplifier sections. 
If a different power amplifier in normal single ended drive is used, then this is still not enough gain. In addition to R75 = 0 ohm change R68 and R69 from 4.22k to 2.15k, and change C68 from 150nF to 330nF.

Updated material list: Orion-subw3-40xo.xls

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(4)  10/21/06  Supplement to the THOR Construction Kit for w-ASP (Rev. 8/25/06)

First shipments of the supplemental documentation were missing the interconnect wiring diagram for combining ORION and THOR and the AT6012 power amplifier: Thor-Orion-wiring-1.doc

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(3)  4.1 Material List on page 12:

1uF has Order Qty and Used Qty of 6.

330nF has Order Qty and Used Qty of 4.

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(2)  4.2 Loading Table, page 14:

1uF has used quantity of 6.

On the MT1 board load an IC socket for U4, not U5.
Add jumper R5. Used quantity 10.

On the THOR EQ-WM1 add C3 at 330nF. Used quantity 4.

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(1)  Up-to-date Material list and loading chart

Install the Excel 97/2000 Viewer on your computer, if you do not have access to the Microsoft Excel spreadsheet program. 

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