PJB DOUBLE FOUR
Contents
1. E 7 Phil Jones Bass PJB DOUBLE FOUR OWNER S MANUAL Thank you for purchasing the PJB DOUBLE FOUR A great deal of dedication and passion went into designing and building this no compromise high performance compact combo amplifier It was conceived to be a dedicated amplifier for the connoisseur bassist Reading this manual will enable you to get the best performance from it so that you may enjoy many years of service READ THIS FIRST e Before using the DOUBLE FOUR please read ALL the instructions e On receipt of product check for any signs of physical damage arising from shipping If any damage is visible contact your dealer e Do not install this equipment in a confined or building in space such as a book case or similar unit and remain a well ventilation conditions at open site The ventilation should not be impeded by covering the ventilation openings with items such as newspaper table cloths curtains etc e WARNING Only use attachments accessories specified or provided by the manufacturer such as the exclusive supply adapter etc e WARNING Please refer the information on exterior bottom enclosure for electrical and safety information before installing or operating the apparatus e WARNING To reduce the risk of fire or electric shock do not expose this apparatus to rain or moisture The apparatus shall not be exposed to dripping or splashing and that objects filled with liquids such as vases2. the changes are processed It is simply the characteristic of the processers and not a fault on the unit All amplifiers will be affected by the room they are in and in fact it can make a huge difference to the sound where you place your amplifier If you place the amp ona table far from any wall this will give you the least bass low frequency output Walls Floor and Ceiling act like a mirror to the amplifier because the sound wave is reflected back and it will magnify the sound So placing the unit on a floor and close to a room corner will give you the most bass output You should experiment to see the best placement for your sound Speakers are a bit like shoes new ones are never as comfortable as worn in older ones and in time speakers will soften up The sound will be warmer and fuller in time and a break in period of playing is required to get the amp to perform its best This can also be done just by playing music through the aux input instead of playing TRANSPORTING AND STORING THE DOUBLE FOUR When transporting in a vehicle it is recommended that you use an external case or heavy duty cover to prevent it being damaged by falling over or other objects falling on it When Storing e Keep ina dry location preferably at room temperature e Donot store in temperatures below 20 Degrees C or above 40 Degrees C e Donotallow it to get wet If this occurs never turn it on in this condition e Donot leave the DOUBLE FOUR permanently connec
3. TURN THE VOLUME DOWN on the DOUBLE FOUR before plugging in your instrument You may notice the clip light blinks once on turn on This is normal and the amplifier is functioning correctly It is just a characteristic of the circuit Positioning the DOUBLE FOUR for Best Sound Often playing in different venues will cause your bass to sound different This is partially due to the acoustics of the hall influencing the low frequency waves that are coming from your speaker Bass waves are large and room dimensions heavily influence them when the walls reflect the sound waves causing them to collide by adding together or canceling each other out This causes some fundamental notes the ones you feel more than hear to ring out louder than others and some notes not to be heard at all Here is an indication of where fundamental bass frequencies are showing open string s approximate frequencies and acoustic wavelength B string 31Hz 36 feet E string 41Hz 27 feet A string 55Hz 20 feet D string 73Hz 15 feet G string 98Hz 11 feet C string 130Hz 9 feet This may give you some indication of the offending notes frequencies that may be booming or resonating louder or quieter than others For example if your speakers are five feet from a wall the open A string may sound weak That could be because the path length of the reflected sound off the wall from your speaker is exactly corresponding to half a wavelength on the open A string causing at that
4. acoustic loading using the acoustic simulation software and calculated exactly the full power cone displacement at every frequency We designed a custom Rectangular Auxiliary Low Frequency Radiator RALFR That is a pneumatically coupled radiator loaded to the rear of the two 4 inch speakers that operates at the lowest bass frequencies only It augments the output of the loudspeakers at frequencies from 30 to 150 Hz It also reduces the cone excursion of the speakers allowing greater power handling The proprietary PJB NeoPower 4 inch speakers are full frequency range to the highest audio frequencies Not only does this give greater clarity and transparency to your instrument but also gives a high fidelity sound to any backing track fed into the auxiliary input Each speaker is fed with its own Pulse Width Modulation PWM amplifier PWM amplifiers are extremely efficient compared to more traditional analog solid state amplifiers converting more electrical energy to power the speakers instead of getting hot Heat in electrical circuits is the enemy to reliability and since the amp is running at lower working temperature the DOUBLE FOUR will give years of service long after other amps have faded away By using dual amplifiers one to each speaker the bass control is greatly improved since the damping factor is doubled Damping factor is the amplifiers ability to put on the brakes stopping the speaker cone from overshoot and tightening up the b
5. in user manual e Connection or operation of the speakers in any way that does not comply with the technical or safely regulations applicable in the country where the product is used e Repairs or modifications by anyone other than authorized PJB service agent e Damages defects caused by force majeure or any other condition that is beyond the control of PJB Should you need any warranty service please bring the DOUBLE FOUR back to the dealer from whom you purchased along with your sales receipt Depending on the complexity of the repair work your dealer may return the defect unit to PJB service center for repair or replacement IN USA American Acoustic Development LLC 8509 MID COUNTY INDUSTRIAL DRIVE ST LOUIS MO 63114 USA Tel 314 814 3383 Fax 656 536 1338 www philjonespuresound com support philjonespuresound com For servicing outside USA please contact our distributor in your country Information can be found on our website
6. ass sound so the sound is punchy tight but never muddy or bloomy out of control bass The cabinet may be as small as a shoe box but it is built to the same standards of all PJB cabinets heavily braced internally and damped with acoustic damping materials to prevent cabinet coloration that can kill the true sound of your instrument What you hear from the DOUBLE FOUR is the closest youcan get to how your instrument actually sounds The DOUBLE FOUR may just be a practice amp but it does not mean that it has to sound like a practice amp The sound is huge for its size and you may find it hard to believe that all the sound from your bass is just coming out of such a tiny jewel AMPLIFIER FEATURES e Switchable high gain input OR low gain stage with mute function e One stereo input for Drum machine or I pod MP3 player e 3 Band EQ e Line Output for recording or driving another amplifier ae al e Sophisticated protection circuitry e 70watt RMS Amplifier e Canuse on any AC voltage worldwide 90 240V PANEL OVERVIEW PHIL JONES BASS 4 o JO PANEL DESCRIPTION 1 Input Jack This is a high impedance input and is designed for all passive and active instruments 2 Clip Light When the amplifier output is clipping the LED will light up with red When the amplifier muted the LED will lightup with green 3 Input Switch Active and passive basses are d
7. gn acoustic loading and the latest digital amplifier technology The DOUBLE FOUR isa single channel bass amplifier that has an auxiliary input for ipad ipod mp3 or drum machine It features 3 band EQ that is perfectly tailored for bass guitar headphone out jack and a line out for recording It is ideal for all kinds of basses and can handle the open B string on a5 string bass with ease The Enclosure It is well known that big speakers are capable of reproducing true bass fundamental frequencies but as you decrease the physical size of a speaker the bass response will fall away Same reason why Violins are small and Double Basses are big So how do you get huge bass sound from a small speaker cabinet Well with our know how of using smaller drivers to get the ultimate bass sound we applied our vast experience to an even smaller driver just 4 inches across It is built with Swiss watch precision it has to be to cope with the extreme signals coming in from an amplified bass guitar Using our extensive R amp D facility which includes the largest anechoic chamber in the bass guitar amplifier industry and the KLIPPEL transducer measurement system it uses lasers we were able to develop the perfect 4 inch loudspeaker We analyzed the neodymium magnetic system the cone behavior at all frequencies in 3D representation cone suspension frame etc until we had achieved a transducer beyond what anyone would have ever though possible Then we looked at the
8. ifferent The output from a passive bass is a higher impedance circuit with less voltage out than an active bass So if you have a passive instrument no internal pre amp then set the switch to passive mode Use active mode for basses that have higher output to prevent signal overload The switch also mutes the input when set to mute 4 Input Level Control Different instruments and also different playing styles and even players will affect the signal level so adjust this control so that the signal overload Clip light does not light up This optimizes the best signal to noise ratio between amp and instrument and will give you the full extent of the amplifiers tone and power 5 Bass Control This is centered on the fundamental frequencies of 4 and 5 string basses Boosting or cutting this will have significant effect on the weight of the tone 6 Mid Range Control This gives the voice of your instrument Generally you will find that cutting this control instead of boosting will have more of a truer bass sound Boosting may be useful for soloing or special effects 7 Treble Control This gives the instrument the definition to the sound Boosting it for slap bass or cutting back for Reggae bass sound If you boost excessively you may get more noise as hiss and that could be due to the noise coming from the pre amp in your bass or a poorly shielded instrument cable PJB has a dedicated bass instrument cable Model BI 12 that is tota
9. lly noise free and actually will improve the tone of your instrument 8 Master Volume This controls the volume of both instrument and auxiliary input 9 Auxiliary Input Level Adjust this to balance you backing track to your bass level 10 Auxiliary Input Jack This is a stereo mini jack and can accept any signal from iPod iPad computer or drum machine 11 Line output jack The pre amp in the DOUBLE FOUR is recording studio quality so the line out is a very pure signal for recording or driving another amplifier 12 Headphone Jack You can use any kind of stereo headphones on this jack but remember you will only sound good in your headphones ifthey are high quality Don t try using those cheap ones you get with a phone you will be disappointed We recommend the best you can afford and PJB have designed a high quality headphone model HD850 that can handle bass guitar many can not and they sound great on music too 13 Power Switch This switches off the amplifier from the DC supply but AC signal will still bein the external supply We advise that you disconnect the power supply from AC source if you do not intend to use the DOUBLE FOUR for long periods of time 14 Power Indicator Will light up when you have DC supply connected and amp switched on 15 DC Input Connect the PJB DC power supply supplied with DOUBLE FOUR here DO NOT USE ANY OTHER POWER SUPPLY AS THIS WILL DAMAGE YOUR AMPLIFIER OPERATION amp POSITIONING
10. particular note to cancel out Where you position the DOUBLE FOUR will ultimately affect your low frequency limit For best results keep the DOUBLE FOUR on the floor Placing it on objects off the floor will cause it to sound thin and lack bass punch Placing the DOUBLE FOUR with the back close to a wall will help reinforce the lower notes Placing it ina room comer will further enhance the low notes Room size makes a large difference in how deep the bass will sound The further the distance to the listener the less the bass will be This is due to the physics of acoustics not the unit itself Unfortunately for bass players low frequencies are always very difficult to control with room acoustics The reproduced wavelengths of the notes you are playing often correspond to the room dimensions in which case the reflected sound off the walls interferes with the sound from the speaker as you get further away from it Getting the most from your DOUBLE FOUR It is important to understand that this is a very different amplifier from conventional analog amp The controls send information to two internal micro computers one for the pre amp and the second for the power amp This information is processed as EQ changes or level changes so it takes a very small amount of time for the computers to act on changes to EQ and volume controls This is known as latency and if you change a control while playing simultaneously you will notice a very slight delay as
11. shall not be placed on apparatus e WARNING The mains plug is used as disconnect device the disconnect device shall remain readily operable e When not in use and during movement please take care of the power cordset e g tie up the power cordset with cable tie or something like that It shall be free from sharp edges and the like that can cause abrasion of the power cordset When put into use again please make sure the power cordset being not damaged If any damages found please look for the service person to replace the power cordset specified by the manufacturer or have the same characteristics as the original one 7 Correct Disposal of this product This marking indicates that this product should not be disposed with other household wastes throughout the EU To prevent possible harm to the environment or human health from uncontrolled waste dispo sal recycle it responsibly to promote the sustain able reuse of material resources To return your used device please use the return and collection systems or contact the retailer where the product was purchased They can take this product for environmental safe recycling OVERVIEW OF THE DOUBLE FOUR With the great success of the PJB Bass Cub we had many requests to make a truly affordable bass practice amp There were two major obstacles it had to be small and have the great PJB sound Using existing parts we could not achieve our goals so we started from scratch with new driver desi
12. ted to a power source SPECIFICATIONS Speaker Rectangular Auxiliary Low Frequency Radiator RALFR Enclosure Speaker Frequency Response 60Hz 15KHz Speaker Compliment 2 x 4 inch proprietary extended range drivers Internal Speaker Impedance 4 Ohms Dimensions WxDxH 8 2 x8 x 6 8 inch 208 x 203 x 172mm Weight 8 8 lbs 4kg Amplifier 70watt digital amplifier with DSP Digital signal processing Signal to Noise Ratio Better than 84 dB EQ off Volume on Full Impedance High Input gt 1MQ 22pF Low Input gt 30KQ 22pF Pre Amp Line Out lt 2KQ Levels High Input 30mV 2V Low Input 50mV 1 5V Pre Amp Out 1 2V Included Parts DC power supply SERVICE WARRANTY INFORMATION The DOUBLE FOUR has a warranty period of 2 years starting from the date of purchase The buyer must complete and return the enclosed warranty card within 14 days of purchase This warranty covers defect in materials or workmanship that occurs in normal use Within warranty period PJB will repair or replace the defect unit free oflabor and parts charge It is the buyer s responsibility to use the unit strictly according to instructions written in this manual and amplifier manual This warranty is not transferable it is provided to original owner only Damage defects caused by the following conditions are not covered by this warranty e Improper handling neglect or failure to operate the unit in compliance with the instructions given
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