AMP MAKER WF-55 Construction Manual Download Page 1

1

www.ampmaker.com

Before jumping in, clear a space on
your workbench. Unpack all of the
components.

Your kit's contents

Start by checking the Kit contents
listing (overleaf). Look through the
electronic components and check
them off one by one.

If this is your first electronics

build, familiarise yourself with the
component values. In some cases, it's
as simple as reading the value from
the body of component (most
capacitors, for example). However,
most resistors are too small to have
printed values, and instead they have
colour coded bands on the resistor

Your WF-55 amplifier kit contains all of the

electronics and hardware parts needed to

make a vintage 4W Tweed-voiced classic.

A M P

M A K E R

WF-55

Construction guide

Summary of Contents for WF-55

Page 1: ...rst electronics build familiarise yourself with the component values In some cases it s as simple as reading the value from the body of component most capacitors for example However most resistors are...

Page 2: ...T On Off V1 ECC83 socket shield V2 6V6 socket clip T1 Power transformer T2 Output transformer L1 Neon 220 240V F1 500mA fuse holder J1 1 4 mono jack socket J2 1 4 mono jack socket J3 IEC chassis plug...

Page 3: ...st be rated for at least this voltage the parts supplied with your kit are rated at 450V Likewise there are some signal caps inside the amplifier that are rated at 600V more than enough to do their jo...

Page 4: ...ve heater supply All valves used in guitar amps need a heater supply the heater is the part of the valve s internal electrodes that glows dull orange when an amplifier is switched on The light orange...

Page 5: ...tion shows the part of the amp that operates directly from the mains supply It includes the fuse On Off switch and a neon indicator Just as important is the connection of the Earth wire from the IEC l...

Page 6: ...are many ways to tweak the vintage 5F1 Champ circuit and you can decide if you want to try that when the amplifier is working properly as standard While it may be tempting to leap ahead and increase...

Page 7: ...7 www ampmaker com...

Page 8: ...ut transformer The output transformer runs across the chassis behind the power transformer Use M4 screws shakeproof washers and nuts and make sure that this transformer s lugs face towards the power t...

Page 9: ...the chickenhead knob rotating it so that when the pot is turned fully clockwise the pointer is at about 5 o clock Fix it by tightening the knob s set screw Finally add the power switch mains socket an...

Page 10: ...stors which are rated at 1W or 2W in the appropriate position For example there are three 100k resistors one of which is substantially thicker than the other two The smaller pair are R3 and R5 in the...

Page 11: ...you to avoid having to desolder components Even if you can read resistor colour codes easily use your multimeter to check their resistance just in case Check twice and cut once Extending a lead that...

Page 12: ...t from the turret board but at this point you re only adding the wire to the turrets not any other component Note that I ve shown the wires connected to the hole in the underside of the turrets Some p...

Page 13: ...wn in the photos and diagrams to avoid any confusion Every amp builder has their own preference and some just go with what Fender or Marshall has used in the past I ve seen some amps which use the sam...

Page 14: ...r and neon indicator If your local mains supply is 110 120V as in the USA or 220 230V as in mainland Europe see the blue and red boxes opposite Take two pieces of red wire and solder them to the upper...

Page 15: ...s up to the neon indicator one wire to each solder lug Now solder all four solder lugs two on the transformer and two on the neon indicator USA and other 110 120V mains The same power transformer also...

Page 16: ...round The ground bus must be more or less in the centre of the chassis and the five diodes should be close to the back of the chassis Now you can start making the connections shown in the wiring diag...

Page 17: ...ocket has three contacts which allows it to short the V1 input to ground when there s no guitar plugged in to lower noise Start by fitting R1 the 1M resistor on the socket itself you may find it easie...

Page 18: ...lve circuit and the top row and the secondary is connected to the speaker output and the bottom row Wire the speaker side first For the speaker output the first decision you need to take is which impe...

Page 19: ...ou do next depends on the speaker output you ve chosen For an 8 16 ohm speaker If you chose 8 or 16 ohms you can solder lug 1 now The photo next page shows an 8 ohm speaker output completed You have a...

Page 20: ...some brown and white wire and solder one each to the two turrets at the junctions of the rectifier diodes one to D1 D3 and the other to D2 D4 as this is an AC connection either way around is fine Twi...

Page 21: ...21 www ampmaker com...

Page 22: ...s of tests on this page is the ONE AND ONLY TIME that you can safely assume that the capacitors are not storing a potentially lethal charge If you power up your amp find problems and then come back to...

Page 23: ...the connections from the turret board to the valve sockets and other components Open the turret board wiring diagram see page 16 for a reminder of where each ground connection ought to be and use your...

Page 24: ...wear loose jewellery I recommend taking it off The test point diagram opposite shows where to measure the voltages inside your amplifier First power up Prepare as follows If you have plugged in the va...

Page 25: ...Now switch your multimeter back to its high AC voltage range and read the voltage from A to B You should get around 280 290V Contact Amp Maker if not 4 Set your multimeter to its high DC voltage rang...

Page 26: ...preamp valve into the Pre flight check If you have a guitar plugged in perhaps from the ground continuity tests you should unplug it Connect a speaker cabinet of the correct impedance to the WF 55 s s...

Page 27: ...D the 6V6 cathode voltage Powering down Now turn the S1 Power switch off and once again set your multimeter to its high DC voltage range and check the C D voltage as the capacitors discharge With the...

Page 28: ...2 5mA 5 Screen current Subtract the preamp current 4 from the combined preamp and screen current 3 to get a figure for the screen current alone Typically this will be about 2 4mA Get in touch if it s...

Page 29: ...be clear very mellow at low volumes more compression and brighter overtones coming in from the midway point turning into a throaty snarl when the volume is at maximum Whatever next This little Champ c...

Reviews: