What would you like to do ? Help us find the most requested user's guides Upload your
user manual Search for a user manual Register Login and access your manuals Reset your password

	Browse all user guides
	The JEFF ROWLAND MODEL 8 product forum
	Upload your user manual
	Sign-up Log in
	Help us find the most requested user's guides
	Include the add-on to download manuals from your site, forum or blog
	Frequently Asked Questions
	Contact Diplodocs team
ALL GUIDES BY CATEGORY Domestic Appliance TV & Audio Car & Motorcycle Phone Computer Camera & Video Music Sport Gardening & Housekeeping Video Game & Software Jewelry & Watch Baby & Toys Hygiene & Health Other

JEFF ROWLAND D E S I G N G R O U P Model 8T/ Ti Stereo Power Amplifier Owner's Manual Introduction Welcome to the Jeff Rowland Design Group "family" and congratulations on your purchase of what is unquestionably one of the world's finest audio power amplifiers. With its combination of features such as numerous function control Jeff Rowland Design Group, Inc. 2911 North Prospect Street Colorado Springs, CO 80907 Phone: 719/473-1181 Fax: 719/633-4158 and interconnection possibilities, precision electronic circuitry and accurately machined chassis components throughout, your Model 8T/Ti Amplifier will offer you many years of musically satisfying enjoyment. Please take a few moments to read the remainder of this Owner's Manual. A thorough understanding of the operational features will allow you to gain the maximum performance and ease of use for which this Amplifier was designed. Please note that your Model 8T/Ti Stereo Amplifier serial number begins with the letter A. This number is recorded below and is also located on the rear panel of the chassis. Please include this number with any correspondence regarding your Model 8T/Ti Amplifier. It has been my joy to create an audio component of enduring value which will reflect a higher ideal of musical and artistic expression. It is my hope that these qualities will enrich your experience of ownership. Enjoy the music! Jeff Rowland President Product Features XLR Balanced Input jacks for balanced (Differential ModeTM) system configurations RCA Input jacks for unbalanced (single-ended) system configurations Two parallel connected speaker output connectors for both right and left channels User-selectable overall gain of 26 or 32 dB User-selectable input impedance of 36k or 600 ohms for both balanced and unbalanced inputs. User-selectable absolute phase on balanced input User-selectable input muting User-selectable switching between balanced and unbalanced inputs Front panel standby/power button illumination can be turned off during listening Optional remote (wired or wireless) power ON/OFF switching Automatic temperature stabilizing circuitry maintains constant operating temperature Standby power condition reduces warm-up time Fail-safe operation provided by user-resetable AC and DC magnetic circuit breakers located on rear panel Quiet, transient-free operation during power and function mode switching Automatic input muting under anomalous input or output operating conditions Balanced Differential ModeTM circuit topology implemented from input to output Plug-in modules, containing critical electronic circuitry, enhance thermal stability, mechanical integrity and serviceability Low-resonance, structurally integrated chassis of precision machined aluminum alloy components Introduction / Product Features Contents 1 5 4 2 3 Initial Inspection Inspect the shipping container for damage. If the shipping container, packing material, amplifier or accessories are damaged or missing, notify your dealer and the shipper (if a claim is to be made). Note: Many shippers require notification and an inspection within twenty-four (24) hours of delivery to ascertain the nature of damages incurred. Your Model 8T/Ti Amplifier has undergone extensive performance evaluations, listening tests, quality control inspections and a minimum seventy-two (72) hour burn-in period prior to shipment and should be in a perfect operational condition upon receipt. If the Amplifier does not operate correctly, please notify your dealer immediately. We strongly suggest that you save all packing materials. If the Amplifier is returned to your dealer or Jeff Rowland Design Group, the original packing materials must be used for shipment. Neither Jeff Rowland Design Group nor the shipper can be held responsible for damages incurred during transit if the original factory packing is not used. All factory returns require that a Return Authorization number be issued by Jeff Rowland Design Group prior to shipment. Contents Ensure that all of the auxiliary components listed below are enclosed within the accessory box. Refer to the diagrams illustrated above and verify the components included. 1 2 3 4 5 AC power cable Four (4) spiked coupling interface supports Four (4) compliant isolation interface supports One (1) speaker terminal hand wrench (7/16 inch) One (1) warranty card (in some countries warranties are provided by the respective importer) Initial Inspection / Contents Front & Rear Panel Function Controls 4 1 5 2 6 3 A Front & Rear Panel Function Controls Before attempting any system interconnection, please familiarize yourself with the front and rear panel controls of the Model 8T/Ti Amplifier. The descriptions below refer to the numbers and letters associated with the features in the diagram above. Front Panel A FRONT PANEL STANDBY/POWER button: Press to operate Rear Panel (Note: All of the switches described below can be switched, if desired, while the Amplifier is operational and playing music.) 1 INPUT SELECT switch: This switch selects either the RCA singleended inputs or the XLR balanced inputs. Note: When the RCA position is selected, pin 2 of the XLR input is shorted to pin 1. XLR INPUT PHASE switch: This switch selects between two XLR connector standards in use worldwide. The XLR standard of associated equipment should be noted and matched with the Model 8T/Ti to achieve correct absolute phase. The Amplifier is non-inverting with respect to XLR Pin 3 when the switch is in the upper position. Furthermore, the Amplifier is non-inverting with respect to XLR Pin 2 when the switch is in the lower position. Regardless of the standard selected, this switch can be used to conveniently reverse the absolute phase of the entire audio system when XLR balanced inputs are used. Note: The XLR standard used worldwide assigns Pin 1 to ground or input interconnect shield potential. OVERALL GAIN switch: This switch selects between a high (32 dB) or normal (26 dB) overall gain structure of the Amplifier. INPUT MUTE switch: This switch removes the internal input signal connection from the Amplifier input circuitry thus permitting input interconnect cables to be removed or inserted safely without switching the Amplifier off. INPUT IMPEDANCE switch: This switch selects between a high (36k) or low (600 ohm) input impedance at the balanced XLR input jacks or unbalanced RCA jacks. FRONT PANEL LAMP switch: When placed in the OFF position, this switch will cease front panel illumination during listening. Front panel indication of operational status is restored when the switch is returned to the ON position. Amplifier. Press again to place Amplifier in standby mode. This button will illuminate when the Amplifier is operational. When the button is not illuminated, all Amplifier inputs are muted and internal circuitry is reverted to power-saving (standby) mode. Note: All ON/OFF power switching should be initiated ONLY with this button. Anomalous operating conditions will automatically switch the Amplifier off (no illumination) and will prevent the Amplifier from being switched back on again until such a condition is eliminated. 2 3 4 5 6 Front & Rear Panel Function Controls Rear Panel Power Connections 4 1 2 1 4 3 Installation Locate the Amplifier as close as possible to its final installation point. Allow access to the rear panel for making connections. The Model 8T/Ti Amplifier is convection cooled, eliminating the need for fan or forced air cooling. When operating, the chassis should have at least two (2) inches of air space around the heatsink areas. Multiple chassis can be stacked vertically thus facilitating an upward flow of warm air currents throughout the vertical heatsink fin areas. This upward flow must not be impeded or recirculated around the chassis if proper cooling is to be maintained. Supplied with your Model 8T/Ti Amplifier are two different support systems. An assessment of the supporting structure should be made to determine the proper system for the Amplifier. Both spiked and compliant interface supports can be easily installed within the indentations on each of the four chassis pods located underneath the corners of the chassis. These system options permit the coupling or decoupling of the Amplifier chassis to the supporting structure. As a general rule, most installations allow the Amplifier chassis to be rigidly coupled to the supporting structure via the spiked coupling interface supports. In carpeted installations, these supports provide excellent coupling from the Amplifier chassis to the rigid supporting structure below. In installations where the integrity of the supporting structure is poor, the Amplifier chassis can be loosely coupled to the supporting structure via the compliant isolation interface supports. This will help attenuate the transfer of spurious energy from the supporting structure into the Amplifier chassis. Note: Another installation option, when incorporating the Battery Power Supply, utilizes its chassis as a stable, high mass structural support for the Amplifier chassis. In this configuration, the Battery Power Supply chassis is rigidly coupled to the supporting structure via the spiked coupling interface supports and the Amplifier is placed directly above the Battery Power Supply and isolated via the compliant isolation interface supports. If desired, a coin may be placed directly under the point of the spiked coupling support to prevent damage to various surfaces (i.e. hardwood floors). Rear Panel Power Connections Important: Please strictly follow the steps in order as outlined below before operating your Model 8T/Ti Amplifier. 1 Verify that the AC MAINS CIRCUIT BREAKER and both RIGHT and LEFT CHANNEL CIRCUIT BREAKERS are in the ON position (green color visible). Verify that the VOLTS AC INPUT identified on the rear panel corresponds to the AC mains voltage of your service area. Install the AC power cable between the Amplifier and an active AC mains outlet. Power Supply Jumpers. Do not remove unless used with the optional BPS-8 Battery Power Supply. If removing, always use the knurled ring to loosen and remove these jumpers and covers as one unit. 2 3 4 Note: If the Amplifier is moved to another location, simply disconnect the AC power cable from the AC mains wall outlet. It is not recommended to use the AC MAINS CIRCUIT BREAKER to remove or connect AC mains power to the Amplifier. Installation / Rear Panel Power Connections Signal Connections 3 2 1 5 4 4 Signal Connections The Model 8T/Ti Amplifier offers unprecedented compatibility with associated audio components. When connecting or disconnecting speaker or interconnect cables, it is only necessary that the INPUT MUTE switch be in the ON position if the Amplifier is already in operational mode. 1 Remote 5 Position INPUT SELECT switch to XLR if you are using XLR balanced interconnects or to RCA if you are using RCA unbalanced interconnects from your preamplifier or other source component. Select one input -- either BALANCED XLR INPUTS or UNBALANCED RCA INPUTS -- on each channel to match your interconnect cable used. A slight click may be heard when the XLR interconnect plugs are installed correctly and latched. The latch (located on the input connector and labeled PUSH) must be pressed to remove the XLR interconnect cable. Unscrew one set of the PARALLEL OUTPUTS connectors on each channel and install the positive and negative loudspeaker cable spade terminals to the respective Amplifier PARALLEL OUTPUTS. Red is normally positive; black is normally negative. Since both upper and lower PARALLEL OUTPUTS are electrically identical, the extra set can be used in loudspeaker bi-wire configurations. ALWAYS USE THE SUPPLIED SPEAKER TERMINAL HAND WRENCH WHEN CONNECTING OR DISCONNECTING LOUDSPEAKER CABLES. DO NOT OVERTIGHTEN THESE TERMINALS. 2 A REMOTE connector (DIN 5-pin) is provided on the rear panel for remotely switching the Amplifier between operational and standby modes. The pin connections on this connector parallel the electrical contacts of the FRONT PANEL STANDBY/POWER button and lamp. An optional wired remote switch or infrared wireless remote sensor can be plugged into the REMOTE connector to facilitate this function. Contact your dealer or Jeff Rowland Design Group for further information and availability of this feature. 3 4 WARNING: Both positive and negative PARALLEL OUTPUTS are electrically active with respect to chassis and/or system ground potential. It is important that both of these outputs are electrically isolated from system ground potential. This precludes the use of this Amplifier in certain loudspeaker switching configurations (sometimes used in retail demonstrations) and testing or servicing situations where either positive or negative outputs can be connected to ground potentials. Failure to observe these precautions may result in damage to the Amplifier and may void your warranty. Consult the factory first if the Amplifier is to be used under these conditions. ! Signal Connections Operation After following the procedures outlined in the Installation/Rear Panel Power Connections and Signal Connections sections, the Amplifier can be turned on by pressing the FRONT PANEL STANDBY/POWER button. Allow approximately twenty (20) minutes for the amplifier to reach operating temperature and maximum performance potential. A short warm-up time is dependent upon the amplifier being plugged in to an active AC mains power source for at least two hours prior to activating the FRONT PANEL STANDBY/POWER button. Therefore, it is recommended that the Amplifier be continuously connected to an active AC mains power source. If you desire to disconnect the AC mains for an extended period of time, simply disconnect the AC power cable from the wall outlet and reconnect upon your return. Slight transients may be heard in the loudspeakers during the AC mains connect/disconnect transitions. Your new Model 8T/Ti Amplifier will require an initial break-in period of at least eighty (80) hours before maximum performance can be expected. Efficient break-in procedures require the Amplifier to be fully operational (playing music). Continuous and noticeable performance improvements will occur during subsequent months of operation. The Model 8T/Ti is provided with a user-selectable input impedance switch. Under normal operating conditions, the high input impedance option should be used. Always use the high input impedance option when tube type preamplifiers, high impedance, or capacitor coupled signal sources are connected to the Model 8T/Ti input jacks. The low impedance input jacks may be used when the signal source is direct coupled and capable of driving a low (600 ohm) impedance. There may be noticeable sonic benefits when a low impedance configuration is used due to the electrical termination of the interconnect cable. The results will vary due to variables in interconnect cable characteristics such as impedance, geometry, construction materials, etc. However, the final judgement of musicality must be empirically determined when using this feature within the conditions defined above. Due to different sensitivities of associated equipment used with the Model 8T/Ti, the OVERALL GAIN switch can be used to optimize the total gain structure of the entire system. This allows the volume control of your preamp to be used in an ideal mid-range position. Model 8T/Ti Performance Specifications Output Power Absolute Phase Continuous RMS watts @ 8 ohms @ 4 ohms Power Bandwidth Slew Rate THD and Noise Damping Factor Output Current Overall Gain & Sensitivity 250 watts 400 watts 0.1 Hz to 160 kHz, -3 dB Unbalanced input Balanced input Input Mute Power Consumption User selectable on rear panel Normal Normal or Phase-inverted User selectable on rear panel 100 watts standby; 300 watts operating, idle; 1200 watts maximum User selectable on rear panel 2 RCA connector 2 XLR connector 2 pair binding posts per channel 17.5 in. (W) x 22 in. (D) x 11.4 in. (H) 44.5 cm (W) x 56 cm (D) x 28.5 cm (H) 18.0 in. (W) x 24.0 in. (D) x 28.0 in. (H) 45.7 cm (W) x 61 cm (D) x 71.1 cm (H) 124 lbs. (56 kg) 164 lbs. (75 kg) 30 volts per microsecond Less than 0.1% at rated power Greater than 100, 20 Hz to 20 kHz, 8 ohms 50 amps continuous, 100 amps peak Inputs Unbalanced Balanced Outputs Dimensions (1 watt, 8 ohms) Input Impedance User selectable on rear panel 26 dB or 32 dB; 141 mV or 71 mV Shipping Dimensions Unbalanced Balanced Common Mode Rejection Ratio User selectable on rear panel 36k or 600 ohms 36k or 600 ohms Weight Shipping Weight Greater than 60 dB, 20 Hz to 20 kHz Because Jeff Rowland Design Group is constantly analyzing new design improvements, we reserve the right to change or modify product specifications without notice or obligation. Operation / Specifications Basic Troubleshooting Asummary of fault conditions, their causes and remedies, are listed below. The Model 8T/Ti Amplifier can produce high power levels which, without well designed protection circuitry, could damage loudspeakers. Therefore, most fault conditions which may occur during use will be indicated by the Model 8T/Ti reverting to a standby condition. JRDG = Jeff Rowland Design Group, Inc. Condition Cause Remedy FRONT PANEL STANDBY/POWER button lamp does not illuminate after pressing, although the Amplifier operates normally. Light bulb defective. Remove STANDBY/POWER button from front panel and replace bulb located under button. Use replacement bulb kit and instructions supplied by JRDG. Change switch position. FRONT PANEL LAMP switch (rear panel) in OFF position. FRONT PANEL STANDBY/POWER button lamp does not illuminate after pressing, and Amplifier does not operate normally. Incorrect power connections or circuit breaker positions on Amplifier. Abnormal operation of Model 8T/Ti Amplifier internal circuitry. FRONT PANEL STANDBY/POWER button reverts to standby condition during listening but can be returned to operational condition. Excessive sub-sonic signals produced by source components. Review Installation/Rear Panel Power Connections section. Consult dealer or JRDG. Repair or replace source component (preamplifier). Identify and correct abnormal conditions such as low frequency rumble and/or acoustic feedback caused by phono playback components (if applicable). Reduce volume slightly or use higher efficiency loudspeakers. Severe clipping of Amplifier circuitry under intermittent overload conditions. Condition Cause Remedy RIGHT AND/OR LEFT CHANNEL CIRCUIT BREAKER switches off occasionally during listening. Excessive load currents drawn by loudspeaker(s) and/or excessive low-frequency program material. Reduce volume slightly or use higher efficiency loudspeakers. Add subwoofer loudspeaker system to relieve load on main system. Intermittent short-circuit on Amplifier PARALLEL OUTPUTS. RIGHT AND/OR LEFT CHANNEL CIRCUIT BREAKER cannot be switched on (when loudspeakers are not connected). AC MAINS CIRCUIT BREAKER (rear panel) switches off or will not remain on. Abnormal operation of Model 8T/Ti Amplifier internal circuitry. Check loudspeaker cable and associated connections. Consult dealer or JRDG. AC mains service voltage too high for Amplifier. Reconfigure Amplifier to proper AC mains voltage operation. Consult dealer or JRDG. Consult dealer or JRDG. Abnormal operation of Amplifier internal circuitry. 50/60 Hz hum noise in loudspeakers. Sensitive source component(s) located too close to Amplifier. Ground loop condition created between components in system. Reorient or increase distance between source component and Amplifier. Break ground loop by lifting (electrically disconnecting) ground connection from AC mains power cord. (For safety purposes, chassis ground is still maintained through input interconnect shield when Amplifier INPUTS are connected.) Use balanced input system configuration (if applicable). 50/60 Hz buzz noise in loudspeakers. High frequency, random or scratching noise in loudspeakers. Unstable conditions created by excessive capacitance in loudspeaker cables. Insert compensation network on Amplifier PARALLEL OUTPUTS connector(s) (available from JRDG). If you have any additional questions regarding installation or operation, please contact your authorized Jeff Rowland Design Group Dealer. JEFF ROWLAND D E S I G N G R O U P