Dallas Amplifier
Contents
1. a screwdriver Turn the amplifier upside down and place on padded and safety certified work surface Loosen the 4 bolts holding the chassis to the top of the cabinet The reverb pan may need to be removed before removing the chassis Ensure the reverb cords are unplugged and remove the hardware holding the reverb pan in place Check that all components are cool so that burns do not occur Then by holding onto the transformers lift the front of the amp so the front control is out the cabinet and carefully pull the chassis out NOTE Capacitors may retain an electric charge and can be dangerous even when the unit is off unplugged and has not been played for an extended period of time USE CAUTION Locate the fuse holders and remove them and check for continuity Blown fuses can indicate a failure condition and should be treated as though a problem exists Check the label for the proper type and rating After all fuses have been replaced and the amp is tested as acceptable and safe reinstall the chassis by working in reverse Be sure to replace the reverb pan and hardware and plug the reverb cords back into place Before installing the back panel ensure the cooling fan cord is plugged into the proper jack Chu Dallas Guitar Amplifier User s Manual agr amp A A few years ago was at the Dallas Vintage Guitar Show and my band was scheduled to perform a few times A friend said Hey You need an amp to play throu2. bird inlays the headstock bird the PRS headstock shape the PRS body shape the PRS scoop design Singlecut Mira and the SE are all registered trademarks of Paul Reed Smith Guitars Custom 24 Modern Eagle SE Custom SC 245 SC 250 Starla Tonare Sewell Blue Sierra and Angelus are all trademarks of Paul Reed Smith Guitars The Birds New Birds are copyrighted by PRS Guitars
3. ST EAD IN mV A ea ae al FUSE 3A 250V WARNING THE RISK OF FIRE OR POSE Tis EOUPHENT TO RAN O AVERAGE BIAS TO 30miV WITH EVERY TUBE CHANGE AVIS POUR REDUIRE LE RISQUE DINCENDE OU DE Croc ELEC TRIOLE POWER STANDBY AND RE BIAS FOR 6LEGC EL34 6CA7 KT77 E PAS EXPOSER GETEX PLL QU UHUNADT NE PAS EXPOSER CET EQUIPEMENT ALA PLUIE QU L HUMIDIT Fuse Blown fuses may indicate that the amplifier needs servicing Use only the type and rating specified on the back of the amplifier See the section on Service Notes for proper fuse servicing and replacement Power Switch This cuts off all power to the amplifier No filament current or tube voltages are supplied Standby Switch When this switch is in STANDBY the amplifier tubes are effectively turned off but are still being warmed by the filaments if the POWER is on Keep this switch set to STANDBY when powering on the amplifier for at least 2 minutes to allow the tubes to warm up This also helps extend the life of the tubes When set to ON the tubes are turned on the amplifier can be used Always check this switch if the amp is ON but no sound is being heard Bias Jacks Biasing and Tube Replacement should be performed only by a qualified technician Speaker Jacks Get into the habit of checking these first The jacks include a connection for 4 8 and l6 ohm loads There is an extension EXT jack with the 4 ohm and 8 ohm connection to connect two 8 ohm Loads if you wish This scenario coul
4. Tech Specs Dallas Amp 50 Watt 100 Watt Power usage 250 Watts 300 Watts Pre Amp Tubes 2 each I2AX7 2 each I2AT7 Power Tubes 2EA 6L6 4EA 6L6 Power Tubes should be purchased as matched sets Use only tubes in pairs or quads that are factory matched Failure to use matched tubes can lead to tube failure and amplifier damage or abnormal operation Main Fuses 100V 50Hz 60Hz 2A250VType3AG 3A250V Type 3AG 120V 60Hz 2A 250V Type 3AG 3A 250V Type 3AG 230V 50Hz I 5A250V Type 3AG 2 5A 250V Type 3AG Filament Fuses 2 each IOA 250V Type 3AG B Fuses 2 each 500mA 440V Type 3AG Reverb 3 Spring Medium Decay Tube Driven Weight Head 34 Lbs 15 5kg 40 Lbs 18 2kg xI2 Combo 54 lbs 24 5kg N A 2x12 Combo 62 lbs 28 2kg 68 Lbs 3lkg Dimensions Head 22 5in X llin X9 75in 22 5in X Ilin X 9 75in 1x12 Combo 22 5in X 20in X 9 75in N A 2x12 Combo 26 5in X 2lin X 9 75in 26 5in X 2lin X 9 75in Service Notes Tubes Tubes are consumables as they have a given usable lifespan They are part of the heart of the tone so keeping correctly operating tubes is essential Tubes can fail catastrophically or gradually and it s good to know what to Look for if they start to go bad Periodically inspect them and Look to see if anything inside the tube is glowing cherry red other than the normal orange glow of the filament This would indicate a situation where the tube is conducting more current than it is capable of handling and most Likely about to fai
5. amps that sound good no matter where the knobs are It is a rare quality that we insisted on hope this hand crafted amplifier gives you years of enjoyment musical results and pride in ownership appreciate your confidence Using your PRS Amplifier IMPORTANT Before using your amplifier refer to the IMPORTANT SAFETY INSTRUCTIONS insert supplied with the product Powering Up Make sure your speaker cabinet is connected to the correct speaker output impedance jack with a high quality speaker cable Do not use guitar cords 2 Make sure the power cord is connected to the correct grounded outlet 3 Make sure there is at Least 6 inches of clearance behind the amplifier to allow for proper cooling Never place the amplifier against a wall or other equipment and keep it clear of other heat sources such as other amplifiers or stoves Make sure there are no flammable items such as curtains behind the amp Do not drape items over the amps that can prevent proper cooling Do not set drinks or other liquids on top of the amp that can spill into the amp 4 To increase the life of the tubes set the Standby switch to the STANDBY position before powering on Turn the POWER switch on and let the amplifier warm up for 2 minutes before setting the standby switch to ON If this is the first time you are turning on the amp check to see if all of the tubes are glowing 5 Plug in the guitar cable turn the volume knob down and turn th
6. d most commonly be the use of an 8 ohm extension speaker along with the internal speaker connect each to the 4 ohm jacks since their combination produces a 4 ohm load Do not connect an 8 ohm Load in the 8 ohm jack along with a 4 ohm or 16 ohm load in those jacks This procedure halves the reflected impedance of each and will not allow ideal operating conditions If you are using more than one speaker they must be the same impedance For example use two 4 ohm speakers or two 8 ohm speakers Never use 2 different speaker impedances You should not mix and match The maximum number of speakers you can safely connect is 2 Always ensure that the speaker impedance matches the correct speaker jack since this amp is designed to be played wide open Mismatching impedances from a lower tap to a higher speaker impedance stresses the amp more than going into a lower impedance mismatch and can cause arcs on the tube sockets failure of power tubes or even failure of the output transformer Confirm that the speaker cabinet you are using matches to the correct speaker jack on the back of the amp For the 4 OHM and 8 OHM speaker jacks a second cabinet may be plugged into the EXT Extension cabinet Note The total speaker impedance must be determined before connecting to the speaker jacks 2009 PRS Guitars All rights reserved Paul Reed Smith PRS the PRS Logo the PRS Paul Reed Smith logo the Paul Reed Smith signature the
7. e standby switch on and wait a few seconds for the bias to settle Bring the volume up and play some tunes Dallas Amplifier Front Panel Controls Qa sWOODDOO VOLUME REVERB TREBLE MIDDLE BASS MASTER Input 4 standard guitar cord Volume The volume is one of the most important controls on the amp Depending on the output of your pickups you can find your sweet spot at various locations on the sweep There will be a point in which actual volume stops increasing and the tone becomes thicker and more compressed Each guitar will react differently and exploring this control should be a source of great enjoyment Reverb The reverb knob controls the amount of reverb added to the guitar signal at the output Adjust to your liking Treble The treble control is very sensitive and should be used with discretion Like all three knobs there are no numbers to encourage you to set the amp with your ears It affects the gain and distortion of the amp and can work effectively with the bright switch to produce more mid 60 s American scooped mid bell tones Just roll back the treble to say II o clock and flip on the bright switch Middle Controls the Mid EQ tone Bass The bass control is more useful in clean settings and should be used a Little more sparingly when overdriving the amp Back off the bass to say 9 o clock when initially experimenting with overdrive Another thing to explore is to turn this control all the way up to p
8. gh and have a friend who makes great amps He took me to the booth of a Texas amp builder Doug Sewell Loved the way his amps sounded and after barely saying hello Doug and were inside rewiring the amp was going to play through Since that day Doug and have spent years rewiring and listening to every single possible variation to finalize the circuits Our goal was to have highly usable and musical amplifiers am not an amp collector am an amplifier user who keeps the amps am presently playing through That said after Doug and got several of the prototypes finalized sold some of my old coveted Live and studio amps because ours sounded considerably better The next step was to take the prototypes to musicians who are known for their amplifier tone as well as their playing What s interesting is that when spoke to these artists about trying the amps they all said the same thing Sure l U use them if love them In a real way amplifiers are musical instruments They are the devices that amplify the sound of the player s hands the guitar and possibly the pedal board They must share many qualities They must work they have to have a beautiful balance of bass midrange and treble the highs should be sweet not harsh they should be easy to operate and be highly musical In addition amps should clean up really well when you turn your guitar down The final quality that Doug and looked for are
9. hase cancel certain frequencies for interesting tonal effects Consider the bass all the way up at about 3 o clock If you like to hang in that sweet spot try the control at about o clock and adjust the treble to taste Master Controls the overall volume of the amplifier Bright Switch The bright switch adds shimmer in the clean settings It allows high frequencies to be unattenuated by the volume pot As previously stated to achieve bell like cleans back off the treble and employ the bright switch Also if you are using a distortion pedal use the bright switch with discretion because it will add sizzle to the higher frequencies If you are trying to achieve smooth fat lead tones the bright switch should be off Jewel Power Indicator Power indicator If the jewel is Lighted the amp is on This does not indicate the standby setting of the amp Note An amplifier may be plugged in and on but a malfunctioning or burnt out indicator will not show the amp is on Check the power cord and Power Switch if the jewel light is not on If these are connected correctly then check the main fuse If the main fuse burns out check for proper speaker connections If the fuses continue to blow the amplifier may need servicing Rear Panel Controls s TO AVOID DAMAGE NEVER OPERATE WITHOUT PROPER SPEAKER LOAD B 1 AS J A C K S 120V 60HZ A Qu 8 Q 4 OHI C KE PEA R JACKS LERT COM RiGHT M EXT 8 OHM EXT BIAS ADJU
10. l Two other conditions to observe are filaments not glowing or 2 a miniature fireworks display inside the tube Any of the above conditions indicate serious problems with the tube and should be taken care of immediately Tubes quite often are the cause of spurious noise in the amp Microphonic tubes will squeal or rattle with the vibrations of the cabinet If suspected tap each tube lightly with a pencil with the amp powered up the suspect tube will let you know Note that there is a normal metallic clinking when doing this but a microphonic tube will be quite Loud Instructions for Qualified Service Technician To install the tubes check that the power cord is not plugged in then remove the wooden back panel with a screwdriver and notice the tube sockets Note that the cooling fan may need to be unplugged from the chassis Looking from the back install the Power tubes EL34 6L6 etc in the left sockets In each case align the center pin guide correctly with the socket making sure that the pin guide key fits with the corresponding slot in the socket The I2AX7 and I2AT7 preamp tubes can then be placed in the smaller 9 pin sockets to the right of the power tubes Please refer to the tube chart inside the amplifier for proper pre amp tube locations Be aware of the pin alignment with these as there is only one way they can fit We utilize tube sockets that allow relative ease of tube installation but never force tubes into the sockets if the
11. re becomes a problem Also never torque the tubes only gently rock them from side to side during insertion or removal After preamp tube installation place the cylindrical spring tension preamp tube covers over the tubes Ensure the cooling fan is plugged back into the jack on the chassis Failing to do so can create a safety hazard Replacing preamp tubes will not require any adjustment but the power tubes will need rebiasing to assure proper operation After power tube replacement initially inspect the tubes often to assure there are no cherry red components within the tube Tubes today can have a wide variety of tolerances and a re bias is highly recommended with new ones Fuses There are 5 fuses installed in the amplifier Only of these the main input fuse is accessible and replaceable by the user There are 4 fuses internally for added safety 2 of these fuses are high voltage fuses and 2 fuses are for the lower filament voltages In all cases labels indicate the type and rating of the fuse Replacement fuses MUST BE THE SAME TYPE AND RATING If they are not you can permanently damage your amplifier Please contact your Local PRS dealer or the PRS accessories web site for information on ordering replacement fuses Instructions for Qualified Service Technician Replacement of internal fuses requires removal of the back panel and removal of the chassis First ensure the power cord is not plugged in then remove the back panel with
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