http://www.ppwatt.com Tweed 5E3 PCB Valve Junior Conversion Build Manual Tweed 5E3 PCB Valve Junior Conversion Build Manual v3.
http://www.ppwatt.com 1. Introduction This manual contains instructions to convert an Epiphone Valve Junior, Harley Benton GA-5 or Legacy Valve Edition into a 14-18 watt Push Pull tube amplifier modeled after the legendary Fender Deluxe Model 5E3 (AKA Tweed Deluxe 5E3). The heart of the amp is the Tweed 5E3 PCB, which conveniently lays out the circuit in a printed circuit board, PCB, package. This manual provides instruction for the assembly of version 3.3 & 3.4 of the Tweed 5E3 PCB.
http://www.ppwatt.com +HUH¶V WKH Y 3&% 7KH\¶UH YHU\ VLPLODU 7KH QHZHU 3&% LV D OLWWOH QDUURZHU DOORZLQJ LW WR ILW PRUH easily in VJr chassis. They also work really well as the basis for a scratch build in a 16x8x2 chassis. 2. Electrical Shock Warning Building tube amplifiers involves working with, or around, high voltages. Working inside a tube amplifier can be dangerous if you don't know the basic safety practices.
http://www.ppwatt.com 3. Disclaimer of Liability PPWatt.com assumes no liability or responsibility, under any circumstance, for personal injury or damage to property or personal property. PPWatt.com reserves the right to make design changes or improvements without obligation to revise prior versions. All specifications are subject to change without notice. The Tweed 5E3 PCB by PPWatt.com is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
http://www.ppwatt.com Table of Contents 1. Introduction ................................................................................................................. 2 ............................................................................................................................................. 3 2. Electrical Shock Warning ........................................................................................... 3 ...............................................................
http://www.ppwatt.com 9. Turn on the Power ..................................................................................................... 36 9.1 Check Your Work .............................................................................................. 36 9.1.1 Take a Break ............................................................................................... 36 9.1.2 Visual Inspection ........................................................................................
http://www.ppwatt.com 4. Project Overview
http://www.ppwatt.com 5. /HW·V JHW VWDUWHG« OK. So you have aOO WKH SDUWV DQG DUH UHDG\ WR VWDUW /HW¶V JHW WKDW (9- FKDVVLV out of the cabinet. 5.1 Remove the EVJ chassis Take off the back panel by removing the seven (7) screws using a Phillips head screw driver. Be careful pulling off the back panel. They are typically stuck onto the chassis. Slowly pull from each side to prevent the tolex from lifting off the panel. Locate the screw caps on the top of the EVJ.
http://www.ppwatt.com 5.2 5HPRYH WKH (9-·V 6WRFN &RPSRQHQWV A few of the stock EVJ parts have to be replaced. The tubes, tube retainers, and stock circuit board need to be removed. 5.2.1 Remove the Tubes and Tube Retainers ,W¶V DV VLPSOH DV x lift the tube retainer off the power tube, x turn the retainer shield until the spring lifts the shield off the per-amp tube, x pull the tubes out, and x unclip the power tube retainer. These items can be discarded. They will not be used later in the build.
http://www.ppwatt.com ,¶YH QHYHU ERWKHUHG ,W¶V an OK OT DV ORQJ DV \RX¶UH XVLQJ D 9 (SL, but the earlier versions are really not so good.) Unscrew the output jacks from the chassis and separate the board from the chassis. The board will be glued to the chassis. It may require some extra work to pick the glue off. Be careful not to damage the board or the output jacks. They will be reused later. Flow the solder to each transformer lead on the output jack board and pull the lead out.
http://www.ppwatt.com 5.2.3 Clean up the Power Transformer 7KH VWRFN (9-¶V SRZHU WUDQVIRUPHU SURYLGHV OHDGV IRU YDULRXV PDLQV VXSSO\ voltages. The extra leads are fastened to dead posts on the stock circuit board for storage. We are going to clean up the inside of the chassis by pulling any unused power transformer leads outside of the chassis cavity. Disconnect these three (3) leads from the stock EVJ circuit board. Version 1 and 2 EVJ will have 12v secondary taps tied off and tucked inside the chassis.
http://www.ppwatt.com 5.2.4 Remove the Volume Potentiometer Unscrew the fastening nut from the volume potentiometer. Pull the volume pot back into the chassis. Leave it connected to the stock EVJ circuit board. The volume pot will be glued to the chassis. This part will NOT be used later in the build, so use whatever force you need. 5.2.5 Remove the Stock EVJ Circuit Board Disconnect these four (4) leads from the stock EVJ circuit board. Lift the ground wire from the star ground post.
http://www.ppwatt.com Remove the stock circuit board and pull all of the power transformer leads to the rim of the chassis. Salvage the ground wire from the stock circuit board for use later. Unscrew the input jack and remove it from the chassis. Set it aside for use LQ DQRWKHU EXLOG
http://www.ppwatt.com 6. Prepare the Chassis 6.1 Layout and Drill The Tweed 5E3 PCB, and control potentiometers require some drilling of both the front panel & bottom of the chassis. 6.1.1 Layout the Tweed 5E3 PCB for Drilling Since the Tweed 5E3 PCB was designed to use the stock EVJ chassis standoffs, one method to mark the additional chassis holes is to install the board. Lay the circuit board in the chassis, align the stock mounting studs, and install two or three screws to fasten the board.
http://www.ppwatt.com I prefer laying the PCB on the outside of the chassis & marking the new drill holes on the outside as I only have a hand drill to use. Notice the PT has been unbolted from the chassis so that it can be moved over enough that the PCB can be lined up correctly with the existing stand-offs. You could just remove it entirely at this stage. Mark the existing stand-offs so that you can use them to line up the PCB & then lightly tape it to the chassis.
http://www.ppwatt.com If you are going to use one of the faceplate designs & get it fabricated yourself at \RXU ORFDO 7URSK\ 6WRUH EXW KDYHQ¶W Jot it yet) and are desperate to drill the front panel you could print a copy from your Laser printer & stick it on the chassis front instead of using the actual plate itself.
http://www.ppwatt.com You want to drill the Noval (9-pin) holes VR WKDW WKH VRFNHW µOLS¶ UHVWV DJDLQVW WKH chassis. The Octal (8-pin) socket holes need to allow the socket to slip all the way through. Deburr or countersink each hole to ensure no sharp edges will cause injury or component failure. I use a Dremel with a grinding stone bit. Notice that the existing VJr EL84 power tube hole needs to be enlarged to cater for the Octal socket.
http://www.ppwatt.com 7. Tweed 5E3 PCB 7.1 Assemble the Tweed 5E3 PCB 7KH DQWLFLSDWLRQ KDV EHHQ NLOOLQJ \RX KDVQ¶W LW" )LQDOO\ WKH DVVHPEO\ RI WKH Tweed 5E3 PCB begins. Did you check you make sure you have all of the SDUWV \RX¶OO QHHG WR FRPSOHWH WKH DVVHPEO\" I wish I did. The graphics used in the assembly of this circuit board will NOT always be an exact reflection of what your board will look like. Various parts may have changed. The order of installation may vary from the picture and this manual.
http://www.ppwatt.com 7.1.1 PCB Standoffs Install the two (2) additional PCB standoffs on the back side of the board. 7.1.2 Tube Sockets The tube sockets get installed on the back side of the board, too. The tube sockets are installed as shown. The noval sockets only go in one way (on the back side). However, the octal sockets need to be properly oriented with the circuit board. Position the notch in these sockets so that they are pointing toward the two noval sockets.
http://www.ppwatt.com 7KH RWKHU VRFNHWV QHHG WR EH µGURSSHG¶ WKURXJK WKH FKDVVLV KROHV LQWR WKH 3&% pin connectors.
http://www.ppwatt.com 7.1.3 Spade Connectors Install the three male spade connectors as indicated. These are for the Output Transformer (OT) leads. The Power Transformer (PT) high tension & heater leads will be soldered directly to the PCB. Extra solder time is necessary to heat the spade connector before solder will flow. Hold the iron on the connector. Feed the solder when the joint is hot enough to flow. Straighten the connectors as the solder joint sets, or hardens. 7.1.
http://www.ppwatt.com If you are XVLQJ 7XEH UHFWLILFDWLRQ \RX GRQ¶W LQVWDOO WKH 'LRGHV ,QVWHDG \RX¶OO FRQQHFW WKH +7 ZLUH IURP WKH WXEH WR WKH µODUJH¶ ' SDG 7.1.5 7KH ´&DVFDGH 3UHDPSµ RSWLRQ The Tweed 5E3 PCB can be configured to have a cascaded V1 gain stage along with many other configurations including tube tremolo & higher power 6L6 versions. Look in the 5E3 section of PPWatt.com and ask for help from the friendly folk over there ;-) (There are many really cool options) 7.1.
http://www.ppwatt.com 7.1.8 Filter Capacitors Insert the four (4) filter capacitors in their locations as indicated on the board. These capacitors are polarized. Be careful to install them by inserting the positive lead (the longer one) into the square pad and the negative OHDG DV LQGLFDWHG E\ WKH GRZQZDUG DUURZ DQG ³-³ V\PERO LQ WKH round pad. Note that C1 ± pointed to by the red arrow, may be a larger capcity cap than the other 3 22uF caps.
http://www.ppwatt.com 7.1.9 Bypass Capacitors Install, solder and trim the 3 bypass capacitors as shown. These capacitors are polarized. Be careful to install them by inserting the positive lead (the longer one) into the square pad and the negative lead (as indicated by the GRZQZDUG DUURZ DQG ³-³ V\PERO LQ WKH URXQG pad. 1RW DOO RI WKH FRPSRQHQWV LQ WKLV SLFWXUH ZLOO ORRN OLNH ZKDW¶V FDOOHG IRU LQ WKH current parts list. I used 22uF bypass capacitors rather than the stock 25uF in this build.
http://www.ppwatt.com 7.1.10 Install the Remaining Components Install, solder and trim all of the remaining components in the circuit. Refer to the latest version of the schematic or chassis layout drawing on PPWatt.com in the FAQ, the Tweed 5E3 PCB, and/or the component package to identify, locate and position component values. If you have one of the first batch of PCBs (version 3.3) there is a labelling error to two of the components in the bottom left. No certain order needs to be followed.
http://www.ppwatt.com Finally, the last of the resistors ! Note that R7 & R8 are not installed on the PCB. They are part of the input jack complex. I use metal film resistors for the 64K & 1M input resistors rather than carbon FRPSV ,W¶V MXVW SHUVRQDO SUHIHUHQFH , KDYH D EXQFK RI WKHP WKDW , ZDQW WR XVH up ! +HUH¶V ZKDW WKH ILQLVKHG 7ZHHG ( 3&% VKRXOG ORRN like. Tweed 5E3 PCB Valve Junior Conversion Build Manual v3.
http://www.ppwatt.com 7.1.11 Input Jack complex The VJr has only one input jack. The Tweed 5E3 has 4. You may as well make the whole input jack complex with new materials. Save the original VJr input jack for another project ! Look at the Chassis Layout diagram to see how you are going to wire together the input jacks. I find it easier to wire them together when they are connected to the outside of the chassis in their actual mounting holes.
http://www.ppwatt.com :LWK P\ ³)HQGHULVK´ ORRNLQJ sockets it looks like this. Note ! 7KLV LV QRW WKH µFRUUHFW¶ ZLULQJ , had to rewire it after doing some WHVWLQJ« Such are the trials & tribulations of the hobby amp builder ;-) 8VH WKH ³FOLII´ MDFNV« 7KH\¶UH much easier to wire. 7.1.12 Tone & Volume Potentiometers I find the easiest way to wire the pots is to mount them on the chassis as well. Use the layout diagram again to see how the lugs & the tone capacitors are wired together.
http://www.ppwatt.com 7.1.13 Connect the Control Leads Hooking up the circuit board is almost done. We now need to solder the wire leads from the control potentiometers and input jack complex & the ground wire. +HUH¶V ZKHUH DOO RI WKH OHDG connections are. The input jack wires connect to the pads marked in yellow. The volume / tone pot wires connect to the pads marked in green. The ground wire connects to the pad marked by the blue circle. You should solder on the ground wire you salvaged earlier now.
http://www.ppwatt.com The populated PCB is now ready to be placed in the chassis so that the leads can be cut to their correct length & soldered to the PCB. 8. Putting it all together 8.1 Install the New Components 1RZ WKDW HYHU\WKLQJ LV RXW RI WKH FKDVVLV WKDW ZH GRQ¶W QHHG WKH FKDVVLV KDV been drilled, and the Tweed 5E3 PCB has been assembled, we can prep the chassis and install all of the new components. 8.1.
http://www.ppwatt.com Repeat the process with the Input Jack complex. The two Instrument channel wires & ground are short & connect at the front of the PCB. The two Mic channel wires are longer, and connect at the back. Same principle applies though. Keep the wires as short as possible ± but not too short ;-
http://www.ppwatt.com Power Supply, Standby, Heaters, and Output Transformer Have you connected the OT & PT back to the chassis yet ? If not, now would be a good time ! 8.1.2 The New Output Transformer Relocate the extra power transformer grommet from the left-front to the new hole drilled for the output transformer. Guide the leads through the grommets and seat the output transformer in place.
http://www.ppwatt.com 6ROGHU D µIHPDOH¶ VSDGH TXLFN FRQQHFW WR HDFK RI WKH EURZQ UHG 27 SULPDU\ µLQSXW¶ ZLUHV This shows the wire colours of the MPS OT15PP output transformer. The red is the B+ lead (T8) & the brown are the 8K leads. The blue wires are the 7K taps. Other OTs are likely to have different coloured wires. The MPS OT20PP 8K tap is brown & blue & the 6.6K tap is white & grey.
http://www.ppwatt.com 8.1.3 The Power Supply connections So close now ! We now need to connect the heater & main HT power to the PCB. These wires DUH VROGHUHG GLUHFWO\ WR WKH 3&% 1R µTXLFN FRQQHFWV¶ IRU WKHVH Again, neatness is important. If cleanliness is next to godliness, neatness is next DJDLQ :H ZDQW WKHVH µQRLV\¶ ZLUHV ZHOO WZLVWHG URXWHG ZHOO DZD\ IURP WKH circuitry. $ SLFWXUH SDLQWV D WKRXVDQG ZRUGV« The orange wires from the PT go to the heater pads.
http://www.ppwatt.com 7KH WZR UHG ZLUHV IURP WKH 37 JR WR WKH +7 SDGV 7 7 ,W UHDOO\ GRHVQ¶W PDWWHU ZKLFK :H GRQ¶W XVH QHJDWLYH IHHGEDFN LQ WKLV FLUFXLW If you are using the stock VJr power switch just solder a jumper between the standby pads, T3 & T4. If you are using a Stand By switch, wire a pair of connecting leads as shown.
http://www.ppwatt.com Good Job!
http://www.ppwatt.com 9.2 Power Up without Tubes 9.2.1 The First Power Up Make sure you are working is a safe area free of any flammable chemicals or vapors. An assembly error may result in the emission of sparks. The tubes should NOT be installed during the initial power up. Plug the amplifier into a speaker cabinet. Match the speaker impedance with the appropriate output jack. Failure to connect a speaker will cause harm and eventual failure of the output transformer.
http://www.ppwatt.com The unloaded B+ voltage should measure the same all the way up the power rail. A slight fluctuation is normal. If a difference greater than 5-10 Vdc is measured, VRPHWKLQJ LV GUDZLQJ FXUUHQW ZKHQ LW VKRXOGQ¶W 7XUQ RII WKH DPS DQG troubleshoot the problem. Turn OFF the amplifier. Tweed 5E3 PCB Valve Junior Conversion Build Manual v3.
http://www.ppwatt.com 9.3 Power Up with Tubes 9.3.1 The Real Test Install the tubes! $UHQ¶W WKH\ SUHWW\" 9HULI\ WKH DPS¶V SRZHU VZLWFK LV LQ WKH ³2))´ SRVLWLRQ ,QVHUW WKH PDLQV SRZHU cord in the IEC mains connector. Secure the black ground lead of your voltmeter to the chassis star ground lug. Plug the amplifier into a speaker cabinet. Match the speaker impedance with the appropriate output jack. Failure to connect a speaker will cause harm and eventual failure of the output transformer.
http://www.ppwatt.com 10. Finish Things Up 10.1 Re-Assemble the Amp Slide the chassis back into the stock cabinet. Fasten the chassis to the cabinet with the stock bolts.
