BYOC CLASSIC BRIT 45 User 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.

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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.
This kit contains only the amplifier chassis. It is intended to be housed in a non-conductive, electrically insulated cabinet or enclosure.
This kit does not come with any such cabinet or enclosure and is not intended to be used without one. It is your responsibility to
house this amplifier kit in a proper cabinet or enclosure before attempting to use it.
Warranty:
BYOC, Inc. guarantees that your kit will be complete and that all parts and components will arrive as described, functioning
and free of defect. Soldering, clipping, cutting, stripping, or using any of the components in anyway voids this
guarantee. BYOC, Inc. guarantees that the instructions for your kit will be free of any majors errors that would cause you
to permanently damage any components in your kit, but does not guarantee that the instructions will be free of typos or
minor errors. BYOC, Inc. does not warranty the completed kit as a whole functioning unit, nor do we warranty any of the
individual parts once they have been used. If you have a component that is used, but feel it was defective prior to you using it,
we reserve the right to determine whether or not the component was faulty upon arrival. Please direct all warranty issues to:
[email protected] This would include any missing parts issues.
Return:
BYOC, Inc. accepts returns and exchanges on all products for any reason, as long as they are unused. We do not accept partial kit
returns. Returns and exchanges are for the full purchase price less the cost of shipping and/or any promotional pricing. Return
shipping is the customer’s responsibility. This responsibility not only includes the cost of shipping, but accountability of deliver as
well. Please contact [email protected] to receive a return authorization before mailing.
Tech Support:
BYOC, Inc. makes no promises or guarantees that you will successfully complete your kit in a satisfactory manor. Nor does BYOC,

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Inc. promise or guarantee that you will receive any technical support. Purchasing a product from BYOC, Inc. does not entitle you to
any amount of technical support. BYOC, Inc. does not promise or guarantee that any technical support you may receive will be able
to resolve any or all issues you may be experiencing.
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.
www.byocelectronics.com/board
When posting a tech support thread on the BYOC forum, please post it in the correct lounge, and please title your thread
appropriately. If everyone titles their threads “HELP!”, it makes it impossible for the people who are helping you to keep track of
your progress. A very brief description of your specific problem will do. It will also make it easier to see if someone else is having or
has had the same problem as you. The question you are about to ask may already be answered. Here is a list of things that you should
include in the body of your tech support thread:
1. A detailed explanation of what the problem is. (Not just, “It doesn’t work, help”)
2. Photo that clearly shows your circuit board.
3. Photo that clearly shows the tube-side of inside of the chassis.
4. Photo that clearly shows the inside of the front of the chassis.
5. Photo that clearly shows your wiring going from the circuit board to the pots and any other switches (only if your kit has non-PC
mounted pots and switches).
6. Does the indicator light come on?
Also, please only post photos that are in focus. You're only wasting both parties' time if you post out of focus, low-resolution photos
from your cell phone.
Credits:
Written by: N.W. Kenning & K. Vonderhulls
Artwork & Photography by: N.W. Kenning & K. Vonderhulls
Quality Control by: R. Matthews
Revision Notes:
None
All material in this document is copyrighted 2015 by BYOC, Inc.

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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
Turning Your Amp on for the First Time……………………page 93 – 95
Biasing…………………………………………………….…….page 96
Operating Overview……………………………………….…...page 97 -98
Diagrams and Schematic………………………………….…...page 99 - 102

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Parts Checklist for Classic Brit 45 Kit
Resistors:
1/2watt (4th 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 – 56K (Green/Blue/Orange)
4 – 68K (Blue/Gray/Orange)
1 – 82K (Gray/Red/Orange)
5 – 100K (Brown/Black/Yellow)
1 – 180K (Brown/Gray/Yellow)
2 – 220K (Red/Red/Yellow)
2 – 270K (Red/Purple/Yellow)
4 – 1M (Brown/Black/Green)
1watt:
2 – 1 Ohm (Brown/Black.Black.Silver/Brown)
1 – 10K (Brown/Black/Black/Red/Brown
2watt:
2 – 470Ohm (Yellow/Purple/Black/Black/Brown)
1 – 8.2K (Gray/Red/Black/Brown/Brown)
3watt:
1 – 1K (Brown/Black/Black/Brown/Brown or just say “1k” on them)

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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 – 0.1uF axial leaded polyester film
5 – 0.022uF axial leaded polyester film
2 – 10uF/150V Electrolytic
1 – 16uF/450V Electrolytic
1 – 220uF/25V Electrolytic
1 – 16+16 Electrolytic (Really big with three terminals)
1 – 32+32 Electrolytic (Really big with three terminals)
Potentiometers:
3 – A1M (Bass, Loudness 1, and Loudness 2)
1 – B5K (Presence)
1 – B25K (Middle)
1 – B250K (Treble)
Hardware:
1 - Chassis
1 - Circuit board
3 - Circuit board hex standoffs
1 – Rotary Switch
2 – ON/OFF SPST Toggle switch
3 - 8 pin tube sockets
3 – Octal Tube Retainer Clips

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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)
3 - Rubber Grommets
25 – M3 screws
12 – M3 nuts
6 - #4 lock washer
4 - Wire nuts
6 – M4 screws
6 – M4 nuts
6 – M4 flat washers
6 - #8 internal lock washers (for the M4 screws/nuts)
4 - #10 nut
4 - #10 flat washer
2 - #10 internal lock washer
2 – lock washer w/solder terminal
Wire:
3’ – Green 20AWG
4' - White 20AWG
3' - Black 20AWG
4' - Yellow 20AWG
4' - Brown 20AWG
2' - Red 20AWG

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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 – Output Transformer (Classic Tone 40-18039)
1 – Choke (Classic Tone 40-18058)

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Chassis Assembly
Step 1: Add grommets

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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. Orient the choke so that the side with the wires is over the grommet hole. The power transformer will already have mounting
screws attached. Use #10 nuts and flat washers for the power transformer. Use the two #10 lock washers for the screws closer to the
outside of the chassis. Use the two lockwashers with solder terminals on the screws closer to the inside of the chassis. Use the M4

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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)

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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.
Orient the 9 pin sockets so that pins 4 & 5 are closer to the back side of the chassis. Use M3 screws to mount the 9 pin sockets. The
chassis will have braze-on nuts already build in.
3b: Add the Octal Sockets. Orient the sockets as shown below. The notch in the socket should be pointed towards the back side of the
chassis. Follow the exploded diagram on page 13 for the order in which to mount the various parts.

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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.

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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. You will not need the yellow terminal. You can bend it out of the way if you
want.

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Step 5: Add flat mount fuse holder. Use 1 x M3 screw and 1 x M3 nut.

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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.

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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.

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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. You can use a thick glue (i.e., a glue that is not runny) to hold it in place better once you have finished
building your amp.

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7b: Mount all the potentiometers and the four remaining ¼” jacks.