We have a range of dedicated subwoofer amplifiers to suit every enthusiast. For those who want the ultimate in accuracy, we recommend our Direct Servo enabled amplifiers. These feature a servo board which has been designed specifically for the driver which will be used. For those who intend to use different drivers, we supply amplifiers without the servo board - they can be used with any driver.
3 different versions- Standard amplifiers: for those who use bass management in their HT receivers
- PEQ amplifiers: includes one band of defeatable parametric EQ
- XLR amplifiers: balanced inputs and master control - multiple subs controlled from the settings on the master sub
Our A series amplifiers are class AB, and H series use class H. All amplifiers use toroidal transformers except A300 which use EI transformer.
All of our amplifiers have the same cut out dimensions so that they are interchangeable. Servo version of these amplifiers are used in all of our finished subwoofers and custom installation kits.
What is the difference between Direct Servo and non servo versions?
Our Direct Servo amplifiers include a servo board which is designed for a specific driver and box (sealed, vented etc). They can only be used for one particular driver. They will not work for a non servo driver. Our non servo amplifiers do not feature the servo board and will work with any driver.
All of our amplifiers feature a modular design, so that non servo versions can be converted later with t he addition of a servo board. Contact us if you have one of our non servo amplifiers and would like to upgrade.
Apart from this difference, non servo versions are identical.
Please note: only non servo versions can be purchased from this page - if you wish to buy Direct Servo amplifiers, please visit the CI custom install product page.
| Nonservo Model | A300 | A370-XLR | A370-PEQ |
| Output Power (4ohms) | 300W RMS | 370W RMS | 370W RMS |
| Input Type | Speaker/RCA | Speaker/RCA/Balanced | Speaker/RCA |
| Master control | NO | YES | NO |
| Parametric EQ | NO | NO | Defeatable one-band |
| Power amp inputs | MOSFETs | MOSFETs | MOSFETs |
| Setup for | HT receiver | w/ or wo/ HT receiver | w/ or wo/ HT receiver |
| Subwoofer LP roll-off | 12 dB | 12/24 dB selectable | 12/24 dB selectable |
| Power filter caps | 4x80V/6800uF | 4x100V/6800uF | 4x100V/6800uF |
| Warranty | 2yr | 2yr | 2yr |
| Control Layout |  |
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Click images to view full size
Download quick guides | A370PEQ | A370XLR | A300
If you plan to build a sealed box and already bought the driver, we strongly recommend the Linkwitz Transform add-on board. Others may recommend using rumble filter or parametric EQ to extend the bass response. However, the bass extension obtained is never as as smooth as the one with Linkwitz transform circuit. For those who haven't bought the driver, we recommend the servo sub option.
Coming soon: high powered H Series
Please note: the layout of H series is identical to other models
Crossover note on all models
A300 amplifiers are designed for use with home theater (HT) receivers in default configuration. The users need to use the bass management on the receiver. The 12db/oct low pass filter on SE amplifiers is used as a fine tuning knob to adjust the overlap between the sub and the front speakers. For those who really need it for a non-HT setup, we have a 12-24db switchable add-on board at additional cost. In addition, this switch is on the circuit board and is not accessible from plate itself. PEQ and XLR amplifiers have a 12db-24db/oct selectable low pass filter to use with or without an HT receiver. That switch is located with the other controls. The 24db/oct on them is implemented as 12db/oct adjustable via a knob plus a 12db/oct fixed at either 50hz or 80hz (two switch positions).
For international shipping, please check out order page. Discount available when ordering a pair. It will be reflected in the on-line ordering system.
| Description (for sealed/vented subwoofers) | Price | ||
| A300 non servo amplifier 12db only | $249 |  |
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| A300 non servo amplifier 12db-24db selectable | $259 | |
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| A370PEQ non servo amplifier (12-24db selectable) | $349 | |
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| A370XLR non servo amplifier (12-24db selectable) | $349 | |
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| H600PEQ non servo amplifier (12-24db selectable) | $509 | |
We also have versions specific designed for general OB subwoofers with a built-in shelving circuit.
| Description (for OB subwoofers) | Price | ||
| A300 OB non servo amplifier 12db-24db selectable | $269 | |
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| A370PEQ OB non servo amplifier (12-24db selectable) | $359 | |
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| A370XLR OB non servo amplifier (12-24db selectable) | $359 | |
View Direct Servo enabled versions >
View GR Research DIrect Servo versions >