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BYOC CLASSIC BRIT 45 Instructions Manual

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Build Your Own Clone
Classic Brit 45
Kit Instructions
(Revision 1.0)
WARNING!!! HIGH VOLTAGE!!!!
Tube amplifiers contain high voltage that can cause injury and even death. Please use extreme caution and common sense when
building this kit. Do not attempt to do anything to your amp while it is plugged in other than take voltage readings as necessary or
actually playing an instrument through it as it was intended.
Don't just turn the power off!!! Always unplug the power cord from the socket before working on your amp!!! The mains supply can
still electrocute you AND the power filter capacitors can still retain a charge powerful enough to kill you. Always unplug the power
cord from the socket before working on your amp.
1

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  • Page 1 Build Your Own Clone Classic Brit 45 Kit Instructions (Revision 1.0) WARNING!!! HIGH VOLTAGE!!!! Tube amplifiers contain high voltage that can cause injury and even death. Please use extreme caution and common sense when building this kit. Do not attempt to do anything to your amp while it is plugged in other than take voltage readings as necessary or actually playing an instrument through it as it was intended.
  • Page 2 DISCLAIMER Build at your own risk!!! BYOC, Inc. is not liable or responsible for any damages, injuries, or deaths that may incur from or while building this kit. It is your own responsibility to follow proper safety precautions. Never attempt to build, modify, repair, or perform any sort of maintenance on your amplifier while the power cord is plugged into an AC power source.
  • Page 3 That being said, we will do our best to help you as much as we can. Our philosophy at BYOC is that we will help you only as much as you are willing to help yourself. We have a wonderful and friendly DIY discussion forum with an entire section devoted to the technical support and modifications of BYOC kits.

  • Page 4: Table Of Contents

    CLASSIC BRIT 45 KIT INSTRUCTION INDEX Parts Checklist…………………………………………………page 5 - 8 Chassis Assembly………….………...…………………….…...page 9 - 20 Wiring (Power Section)…………….………………………….page 21 - 53 Populating the Circuit Board……………..…………………..page 54 - 68 Wiring (Tube Side)…………………………………………….page 69 - 77 Wiring (Potentiometer Side)………..…………………………page 78 – 90 Wiring Layouts/Diagrams……………………………………..page 91 - 92...

  • Page 5: Parts Checklist

    Parts Checklist for Classic Brit 45 Kit Resistors: 1/2watt (4 color band will either be silver or gold): 1 – 470 ohm (Yellow/Purple/Brown) 2 – 820 ohm (Gray/Red/Brown) 1 – 10K (Brown/Black/Orange) 1 – 15K (Brown/Green/Orange) 1 – 27K (Red/Purple/Orange) 2 –...
  • Page 6 Diode: 1 – 1n4007 Capacitors: 1 – 47pF (Red with ‘47’ on the body) 1 – 100pF (Red with ‘100’ on the body) 1 – 250pF (Red with ‘250’ on the body) 1 – 500pF (Red with ‘500’ on the body) 4 –...
  • Page 7 3 - 9 pin tube socket w/shield 6 – ¼” Shorting Mono Jacks 1 - Indicator Lamp 1 - 6' 3-conductor power cord 1 - Power cord socket 2 – black screws for power cord socket 1 - Panel mounted fuse holder 1 - Flat-Mount Fuse Holder 1 - Mains Fuse (3A Slow-Blow for 120V, 2A Slow-Blow for 220V or 240V) 1 - HT Fuse (500mA)
  • Page 8 3.5' - Bare Bus Save the wire you clip from the transformers as well. This will provide you with more than enough wire to complete your kit. Tubes: 3 – ECC83 2 – KT66 1 – GZ34 Transformers: 1 – Power Transformer (Classic Tone 40-18033) 1 –...

  • Page 9: Chassis Assembly

    Chassis Assembly Step 1: Add grommets...
  • Page 10 Step 2: Mount the transformers. Orient the power transformer so that the side with the green wires is towards the “tube side” of the chassis. Orient the output transformer so that the side with the orange/blue/yellow/green wires is towards the “tube side” of the chassis.
  • Page 11 screws, M4 nuts, M4 flat washers, and #8 lock washers to mount the output transformer and choke. Step 3: Add the tube sockets (red arrows)
  • Page 12 3a: Adding the 9 pin sockets - First crimp pins 4 & 5 of the 9-pin sockets. You don’t really have to do this. When you hook up the heater wires, you will need to connect pins 4 & 5. Some people think crimping these two pins together makes it easier, but if you don’t want to do this, you can just use wire to jump the two pins together.
  • Page 13 Only add the ring terminal to the power tube sockets. Do not add a ring terminal to the rectifier tube socket Use M3 screws and M3 nuts. See next page for exploded diagram.
  • Page 15 Step 4: Mount the 16uF x 16uF capacitor to the outside of the chassis. Use the mounting ring to mount to chassis. Use M3 screws to mount to chassis. Use M3 screw and nut to tighten clamp. Make sure the red terminal is not touching the chassis. If it is, resituate the capacitor in its mounting ring so that it is not touching.
  • Page 16 Step 5: Add flat mount fuse holder. Use 1 x M3 screw and 1 x M3 nut.
  • Page 17 Step 6: Add the rear plexi panel and rear panel mounted parts !!!!The plexi panels are EXTREMELY DELICATE!!!! 6a: Mount the AC Power Cord Receptacle. Use black flat head screws for power cord receptacle.
  • Page 18 6b: Mount the rotary switch. Bend the rotary switch tab flat before mounting to the panel. 6c: Mount the two speaker jacks and the panel mounted fuse holder. After these are in place, use an M3 screw to secure the far end of the rear plexi panel.
  • Page 19 Step 7: Add the front plexi panel and panel mounted parts 7a: Add the Switches and lamp. Orient the toggle switches so that the “ON” arrow is pointing in the same direction as the “ON” label on the plexi panel. The lamp is not mounted with any nuts or bolts. You simply push it through its hole and it will lock in place. The lamp may be loose fitting.
  • Page 20 7b: Mount all the potentiometers and the four remaining ¼” jacks.

  • Page 21: Wiring (Power Section)

    Wiring (power section) Step 1: Solder the High Voltage Center Tap (red/yellow) wire to 500mA flat mount fuse holder.
  • Page 22 Step 2: Cut the orange, gray, and white wires. Cut the brown wire if you are using 120V. Cut the black wire if you are using 240V. These are you mains wires for the power transformer. Leave them long enough so that you can switch them if you need to at a later date.
  • Page 23 Step 3: Twist the yellow wires together and place them into pins 2 and 8. Solder pin 2 (Green arrow) DO NOT solder pin 8 (red arrow) yet. We still need to add another wire to pin 8 and it’s much easier to just make one solder joint. TIP: When soldering the octal solder lugs, be careful not to use too much solder.
  • Page 24 Step 4: Twist the red wires together and place them into pins 4 and 6. Solder pin 4 (green arrow) DO NOT solder pin 6 (red arrow) yet.
  • Page 26 Step 5: Connect the center terminal of the 3A fuse holder to the “off side” of the MAINS toggle switch using black wire and solder.
  • Page 27 Step 6: Connect the remaining 3A fuse terminal to the ‘L’ terminal on the power socket using black wire and solder.
  • Page 28 Step 7: Connect the black (120V) or brown (240V) and one of the pilot light wires to the “on side” of the MAINS toggle switch and solder. The leads from the pilot light are not polarized, so it doesn’t matter which wire you choose to connect at this point.
  • Page 29 Step 8: Connect the Blue (common) and remaining pilot wire to the ‘N’ terminal of the power socket and solder.
  • Page 30 Step 9: Connect pin 8 of the rectifier socket to the “off side” of the standby toggle switch and solder both points. Remember that there should already be a yellow wire inserted into pin 8. This step is why we did not solder that till now.
  • Page 31 Step 10: Install 32uF+32uF capacitor as shown. You will use the remaining capacitor retainer, M3 nut, and 3 x M3 screws just like you did for the 16uF + 16uF capacitor.
  • Page 32 Step 11: Connect the red terminal on the 32uF+32uF cap to the “on side” of the standby toggle switch (with a piece of red wire), black choke wire, and brown output transformer wire (red arrow) as shown. The choke will have 2 black leads.
  • Page 33 Step 12: Connect both negative terminals of the two mounted electrolytic capacitors, the green/yellow CT wire (red arrow), and the AC power socket ground terminal to terminal washer mounted to the power transformer closest to the tube side of the chassis.
  • Page 34 Wiring diagram for steps 1 - 17...
  • Page 35 Step 13: Add bus wire to the speaker jacks. Solder where the green arrows are pointing. Do not solder where the red arrows are pointing.
  • Page 36 Step 14: Connect the yellow output transformer wire (Common) to the sleeve bus and solder.
  • Page 37 Step 15: Connect the orange, green, and blue output transformer wires to the rotary switch as shown and solder.
  • Page 38 Step 16: Connect the tip bus to the pole of the rotary switch with white wire and solder.
  • Page 39 Step 17: Connect the Output Transformer primaries to their respective sockets. Black to pin 3 of the V5 power tube, which is closest to the power transformer. Red to pin 3 of the V4 output tube as shown.
  • Page 40 Step 18: Connect a 1 ohm 1 Watt resistor from pins 1 & 8 of the V5 power tube (tube closest to the power transformer) to the terminal ring (page 13) and solder. It is difficult to see in the picture, but one end of the resistor is threaded through both pins 1 & 8.
  • Page 41 Step 19: Repeat the previous step for the V4 power tube, but this time, also add a black wire to the terminal ring. Connect the other end of the black wire to the remaining unsoldered lug on the speaker jacks. You should now have all of the lugs on the speaker jacks soldered.
  • Page 42 Step 20: Connect the 6.3V heater wires from the power transformer to the filament pins of the power and preamp tubes. Start with the power tubes. One green wire goes to pin 2, the other to pin 7 of each power tube. It does not matter which green wire goes to which pin.
  • Page 43 Step 21: Continue daisy chaining the heater wire to the pre amp tubes. Pre amp tube filament pins are 9 and 4/5. You will need to jumper pins 4 and 5 if you elected not to crimp them together earlier.
  • Page 44 Step 22: Connect the two 470 ohm 2Watt resistors between pins 4 and 6 of the power tubes as shown. Be sure to only solder pin 4 (green arrow).
  • Page 45 Step 23: Jumper pins 6 of both power tubes together with brown wire as shown. Insert one end of the 1K 2Watt resistor into pin 6 of the V4 power tube (red arrow). Leave the other end hanging out. Solder pins 6 of both power tube sockets now.
  • Page 46 Wiring diagram for steps 18 - 28...
  • Page 47 Step 24: Connect a bare bus wire to the back of the potentiometers as shown. We will refer to this as the “ground bus”. If you are having trouble connecting the bus wire to the back of the potentiometers, you can rough up the backs with some emery cloth or a file, this should help with solder adhesion.
  • Page 48 Step 25: Connect a .1uF capacitor between lugs 1 and 2 of the B25K Presence potentiometer. Thread the extra lead through lug 1 and solder it to the back of the potentiometer as shown.
  • Page 49 Step 26: Prepare the bottom row of input jacks. Connect a 1M 1/2Watt resistor between the tip and sleeve terminals of each jack, threading the extra lead through the sleeve terminal to the tip disconnect terminal as shown. Connect a 4” piece of black wire to each sleeve terminal. Solder the sleeve terminal only. They should look like the picture above.
  • Page 50 Step 27: Use ¾” of bus wire to connect the sleeve terminal of the other input jacks to the tip disconnect terminal as shown. Only solder the terminals with green arrows.
  • Page 51 Step 28: Mount the input jacks and connect the black wires to the ground bus at the green arrow.
  • Page 52 Step 29: Connect the remaining terminal of the ½ amp fuse holder and the ground bus to the last terminal washer mounted to the power transformer and solder at the green arrows.
  • Page 53 wiring diagram for steps 29 - 34...

  • Page 54: Populating The Circuit Board

    Populating the Circuit Board Step 1: Run bus wire along lower tier of the 3 turret lugs as shown.
  • Page 56 Step 2: Insert trimpot so that one wiper is not inserted into a turret lug as shown.
  • Page 57 Step 3: Make 2 short bus connections. Wrap bus wire around the lower tier of turret lugs at red arrows.
  • Page 58 Step 4: Insert all components into circuit board. Insert leads into openings of turret lugs. DO NOT solder the end of the 8K2 2Watt resistor (red arrow). Solder all the other turret lugs and bus wire. It is easier to solder the bus wire connections first.
  • Page 59 Drawing of component placement. DO NOT solder the red spot yet.
  • Page 60 Step 5: Make bare bus connection on underside of board between 15K/56K/10uF junction and 220K/220K junction. Make a 2 connection between 820Ohm/220uF junction and 820Ohm/100K junction. Make a 3 connection between 100K/100K and “tube side” of the 10K 1W. Make a 4 connection between 82K/100K and “potentiometer side”...
  • Page 61 Step 6: Make a jumper connection on the underside of the board between the 82K/100K and the “potentiometer side” of the 8K2 2W junction and another between the 10K/.1uF and the “potentiometer side” of the 27K as shown. Top-side picture with component values and the underside wires. Top of pic is the potentiometer side. Bottom of pic is the tube side.
  • Page 62 Example of wire connections to top tier of turrets.
  • Page 63 Step 7: Connect off-board wires to top tier of turret lugs on pot side of the board. Start with the “potentiometer side”. Use 6” of white wire off the 8K2 2W resistor. Use 10” of red wire of the 180k resistor. Use 4” of wire for all other wires. Here we are using black wires for all ground connections and we are alternating white, yellow, and brown with all others.
  • Page 64 Step 8: Connect off board wires to the two 68K/68K junctions and 500pF/270K/270K junction. Thread the wires through the board as shown at the red arrows.
  • Page 65 Step 9: Add the rest of the off-board wires to the “tube side” of the circuit board.
  • Page 66 Step 10: add the 3 hex standoffs at the red arrows. Use M3 screws.
  • Page 67 Top-side component picture showing the location of the standoffs in green.
  • Page 68 Step 11: Mount the circuit board. 11 a: Run the white and yellow wires from the two 220K/.1uF junctions under the board so they stick out on the “tube side” (red arrows). 11 b: Make sure you can get to the remaining choke wire and 1K 2Watt resistor (red arrows).

  • Page 69: Wiring (Tube Side)

    Wiring (Tube side) Step 1: Connect the white and yellow wires from the previous step to pin5 (shown at green arrows). A: White wire to V4 B: Yellow wire to V5...
  • Page 70 Step 2: Connect the open end of the 1K 2W, remaining choke wire, and 6” of red wire to the last unsoldered turret lug at red arrow. WARNING!! A: DO NOT make wires/leads so long that they go through the turret lug and out of the other side. They may touch the chassis and cause a short.
  • Page 71 Step 3: Connect the red wire you just added in step 2 to the YELLOW terminal of the 32uF+32uF electrolytic capacitor (yellow arrow).
  • Page 72 Step 4: Run a bus wire between pins 3 and 8 of V1. Solder pin 8, DO NOT solder pin 3 yet. Step 5: Wire V1. The off-board wires are laid out with the intention of progressing from left to right. Start with the brown wire that connects to pin 3 and then work your way left to the yellow wire that connects to pin 6.
  • Page 73 Step 6: Add the 100k resistor and jumper to V2. Thread one end of a 100K 1/2W resistor through pin 1 of V2. Bend the lead around and thread through pin 7. Insert the other end into pin 6. Solder pins 1 & 7 (Green arrows) DO NOT solder pin 6 (red arrow).
  • Page 74 Step 7: Make the rest of the off board connections to V2. Again, move from left to right.
  • Page 75 Step 8: Run bus wire between pins 3 and 8 of V3. Solder pin 3, DO NOT solder pin 8 yet. Step 9: Make the off board connections to V3 as shown. Solder the pins now.
  • Page 76 Step 10: Connect the last off board wire from the 27K resistor to the same solder lug on the rotary switch as the blue 16 Ohm wire (green arrows). There is not enough room to fit this wire into the lug, so simply tack solder it to the lug.

  • Page 77: Wiring (Tube Side)

    Wiring diagram for steps 1 – 10 Wiring Tube Side...

  • Page 78: Wiring (Potentiometer Side)

    Wiring (Potentiometer side) Step 1: Connect the red wire from the 180K resistor to pin 6 of the V6 rectifier tube socket (green arrows).
  • Page 79 Step 2: Connect the white wire from the 8K2 2Watt resistor to the RED terminal of the 16uF+16uF capacitor (green arrows).
  • Page 80 Step 3: Connect all black wires (green arrows) to the ground bus.
  • Page 81 Step 4: Connect the brown wire from the 27K to lug 3 of the Presence pot.
  • Page 82 Step 5: Connect lug 1 of the Bass pot to lug 3 of the Middle pot as shown.
  • Page 83 Step 6: Connect lug 1 of Middle, and both Loudness pots to the ground bus as shown.
  • Page 84 Step 7: Connect lug 2 of the bass pot to lug 1 of the Treble pot. Solder on the green arrow. DO NOT solder on the red arrow yet.
  • Page 85 Step 8: Make the rest of the connections to the Middle and Treble pots.
  • Page 86 Step 9: Insert the 100pF cap between lugs 2 and 3 of the High Treble Loudness pot. DO NOT solder anything yet. Step 10: Make the rest of the connections to the loudness pot. Solder the connections now.
  • Page 87 Step 11: Use bare bus wire to connect the tip of the lower input jacks to the disconnect tip of the upper jack. Solder the lower jack at the green arrows. DO NOT solder the disconnect tip (red arrows).
  • Page 88 Step 12: Connect the yellow wires to the tip terminals of the upper input jacks.
  • Page 89 Step 13: Connect the white wires to the disconnect tip terminals.

  • Page 90: Wiring (Potentiometer Side).........................................

    wiring diagram for steps 1 – 13 of wiring potentiometer side...

  • Page 91: Wiring Layouts/Diagrams

    120V Layout Go to http://www.byocelectronics.com/jtm45-120v.pdf for high-res PDF.
  • Page 92 240V Layout Go to http://byocelectronics.com/jtm45-240v.pdf for high-res PDF Note: The difference between 120V and 240V wiring is using the brown wire on the transformer instead of the black, and a 2Amp fuse for the Mains Fuse.

  • Page 93: Turning Your Amp On For The First Time

    Turning your amp on for the first time Step 1: Make sure your AC power cord is NOT plugged in. Do NOT install any of the tubes yet. Do not plug a speaker into the speaker jack. Do not plug any instruments into the input jacks. If at any point in this process, you smell smoke, see sparks, or hear any loud electrical hum noises, immediately pull the AC power cord from the wall socket.
  • Page 94 GZ43 ECC83 Step 8: With the mains switch off and the AC power cord unplugged from the wall, now install the 500mA fuse into the flat mount fuse holder and install the GZ34 rectifier tube into the V6 tube socket. When testing your amp voltages, always keep one hand in your pocket and wear shoes with rubber soles.
  • Page 95 mains switch on. The rectifier tube should start to warm up and glow. Hopefully you know that vacuum tubes (especially the rectifier tube) get very hot once they are warmed up. You must allow adequate time to pass for them to cool off before you attempt to touch them. If you measure the voltage at the red terminal of the 32uFx32uF electrolytic capacitor, you should read approximately 450VDC.

  • Page 96: Biasing

    Step 15: Install the ECC83 tubes. Plug the AC power cord into the wall. Turn the mains toggle switch on. Keep the standby switch off. You should see all the tubes start to heat up and glow. Step 16: Turn all the knobs down and take the amp out of standby. You should hear a soft white noise start to come out of the speaker.
  • Page 97 Front Panel This should be pretty standard stuff for the most part, but the JTM45 does have some peculiarities. You probably won’t ever want to use the HIGH TREBLE channel unless you are jumpering it with the normal channel. It will typically be much too bright for most peoples’...
  • Page 98 Power Cord Socket: Plug your power cord in to this. Fuse Holder: This is where the fuse goes. It says 2AMP because, but be sure to use a 3A if you are in a 120VAC country. Impedance Selector: Set this 3 position switch to match the impedance of the speaker(s) you are using. Speaker Jack: Insert speaker cable here.

  • Page 99: Diagrams And Schematic

    Diagrams and Schematic Circuit board (top side)
  • Page 100 Circuit Board Wiring (showing from top side) Heater Wiring for hi res pdf go to http://www.byocelectronics.com/jtm45heater.pdf...
  • Page 101 Schematic For hi res pdf go to http://www.byocelectronics.com/brit45schematic.pdf...
  • Page 103 For technical support, visit www.byocelectronics.com/board Written by: N.W. Kenning & K. Vonderhulls Artwork & Photography by: N.W. Kenning & K. Vonderhulls Copyright BYOC, Inc. 2015...

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