background image

10

Notes

Op Amp may be changed to suit

Individual styles.

Batteries available from Clicks at 

R45, Dischem are R39,00

Other tins maybe used or a 

similar style enclosure.

CI and C6 maybe substituted to suit

Item

Qty

Ref

Value

Description

Comments

1

2 C1,C6

3.3uF

Cap Bipolar

Maybe swopped out

2

2 C4,C5

470uF

Cap. Radial Electrolytic

3

1 D1

BL-B6431-TK

LED 3mm RED

Cololur maybe changed

4

3 H1,H2,H7

2SIP100

Pin Header Single Row

Pads on PCB

5

4 H3,H4,H5,H6

3SIP100

Pin Header Single Row

Pads on PCB

6

2 R2,R7

100k

Carbon Film

7

2 R3,R8

1k

Carbon Film

8

2 R4,R9

10R

Carbon Film

Precision device

9

2 R5,R10

10k

Carbon Film

10

2 R11,R12

4k7

Carbon Film

11

1 R 13

6k8

Carbon Film

12

1 U1

TL072

Dual FET INPUT OP. AMP.

Maybe swopped out

14

1 R14 

A10k

Dual Log PCB pot

15

1 KB1

Volume knob

16

1 S1

SPST on/off

17

2 SKT1/2

3.5 mm stereo jack socket

18

2 BATplug

PP3 Battery leads

19

2

PP3 batterys

Originals give 36 hrs

20

1 PCB1

PCB

21

1 V1

Vinyl sheet

Must be cut to size

22

1

0,2 mm red wire

23

1

0,2 mm orange wire

24

1

0,2 mm yellow wire

25

1

0,2 mm red wire

26

1

Solder wire

27

2

Spacer for knobs

28

1

Heat sleeve

29

1

Press stik

30

6

Cable ties

Optional

31

1

Red RCA socket

32

1

Black RCA socket

33

1

Siemens 1 uf

34

1

2,1 mm power socket

35

1

2700 uf capacitor (axial)

36

1

100 nf capacitor 100 v

37

1

Cable saddle

38

1

Capacitor plate

39

1

OPA 1642 (and adaptor)

40

1

Mtg plates with screws

Summary of Contents for KWELA TONES

Page 1: ...Headphone Amplifier Type kt1 Kit assembly instructions 1 June 2020 http www lintaudio co za gallery kwelatones pdf ...

Page 2: ...pplied to experiment with and this is known as rolling page31 The amplifier s design is quite simple It consists of only a few components can be assembled on a small printed circuit board has a lower parts cost than other headphone amplifiers and can run for many hours on two 9 volt batteries Our tests show at least 80 hrs on a set The CMoy headphone amplifier can be fitted into a Fisherman s frie...

Page 3: ...nd Right connections Resistor component codes Bending component leads Capacitor codes Preparing materials PCB assembly Preparing materials Preparation of the tin for drilling 2 types of tin Pre assembly of tin before drilling PCB assembly Op Amp connections Connect the audio output jacks Connect cable to controls Volume control connections Now the cables LED window Testing Before closing the lid e...

Page 4: ...s the control circuit uses high quality materials The unit is NOT a hifi amplifier and is not intended for such usage It does however perform exceptionally well with a normal MP3 cellular telephone or other audio source If using a Android cell phone some outstanding DAC improver digital to analogue converter music player apps are available in the play store This will provide a outstanding sound so...

Page 5: ...o in socket Use a high quality standard three pole AUX cable that are freely available Connect headphones to the output socket 3 5 mm 3 pole are fine Your phone may have a app available that is a improvement over the standard audio output Look for a app that is a DAC this is a digital to analogue converter this may improve the way sound Is played by your cell phone NOTE Avoid listening at too high...

Page 6: ...Headphone amplifier connection details Audio input 3 5 mm jack ON OFF Switch Headphone socket Volume control ...

Page 7: ...7 Use 2 x PP3 batteries ...

Page 8: ...e required A small toothbrush and benzine to clean the pcb after soldering A smartphone will aid in determining left and right headphone connections when connecting Download a left and right app from a app store as this makes it very simple to set the correct speaker when assembled Benzine and a small toothbrush will be required to clean the printed circuit board when complete The kit is supplied ...

Page 9: ...9 KWELA TONES Schematic ...

Page 10: ... 2 R5 R10 10k Carbon Film 10 2 R11 R12 4k7 Carbon Film 11 1 R 13 6k8 Carbon Film 12 1 U1 TL072 Dual FET INPUT OP AMP Maybe swopped out 14 1 R14 A10k Dual Log PCB pot 15 1 KB1 Volume knob 16 1 S1 SPST on off 17 2 SKT1 2 3 5 mm stereo jack socket 18 2 BATplug PP3 Battery leads 19 2 PP3 batterys Originals give 36 hrs 20 1 PCB1 PCB 21 1 V1 Vinyl sheet Must be cut to size 22 1 0 2 mm red wire 23 1 0 2 ...

Page 11: ...11 Overlay component by part number ...

Page 12: ...12 Overlay assembly by component values ...

Page 13: ... solder joint 13 Always ensure that the joint is not moved whilst cooling this will cause a matt finish A shiny joint will be correct joint Please ensure that you use a fine tipped soldering iron DO NOT OVERHEAT JOINTS WHEN SOLDERING ...

Page 14: ...d Right connections 14 Ring right red cable Tip left white cable Barrel signal ground Please note We have noticed some dodgy cables that are swopped around always test with a cell phone app to confirm left and right ...

Page 15: ...Resistor component codes 15 If in doubt always check values with a multimeter ...

Page 16: ...component lead Take care when bending a component lead not to damage the die of the component Always use pliers to prevent undue strain on the die Always ensure a diode is correctly Inserted to the PCB or the system will not work ...

Page 17: ...sed with the long leg as the positive known as non polar These are part numbers C1 and C6 value 3 3 uf or also known as 3u3 Power and capacitors are polarised electrolytic the device is marked and the long leg is always the positive These are part numbers C4 and C5 value either 220 uf or 470uf ...

Page 18: ...materials ready for assembly then you can focus on the assembly NOTE that the Lozenge tin needs to be marked carefully a similar tin to Fisherman s Friend is ideal The PCB has to be separated as required if using a wooden enclosure 4 screw holes are provided ...

Page 19: ...ons of each hole mark the hole centre 9mm from the bottom from the bottom Lightly centre punch each centre holes are as per the labels 7 mm for volume and 6mm for the switch Mark light hole as per your choice 1 5 mm Hole height from the bottom is 9 mm Spare labels are provided for this purpose ...

Page 20: ... dimensions on it Then mark the matrix to drill holes Then apply labels to the tin and mark the positions of each hole mark the hole centre 9mm from the bottom Lightly centre punch each centre Volume is 7 mm in the centre and the switch hole and sockets are 6 mm 9 mm Preparation of the tin for drilling ...

Page 21: ...always nice to preassemble the tin Tip 1 make tea mark the vinyl sheet to the perimeter of the tin and apply in the tin Then put the parts in the correct spots Look listen and decide To see all is in order Now you are ready for the PCB assembly ...

Page 22: ...o read the components Open the packets when you need to use them Start with the two 10R resistors and the two 4k7 resistors which are watt footprint then proceed with the other resistors Then the caps check the positive and negative orientation the long lead is the positive Then finally the LED the flat on the side is negative Then the DIP I C socket Don t overheat the PCB on assembly NOTE if usin...

Page 23: ...Op Amp connections for reference 23 Its nice to trace the tracks and see these connections ...

Page 24: ... joint to tidy the assembly on completion The black wire goes to the barrel Three wires are required for the headphone connection Solder the three cables to make a neat joint Twist wires remember that you look at it The pp3 cables are complete with cables these are connected to 2 connections H and H 2 Red to positive and black to negative Solder the cables onto the PCB as explained The switch is c...

Page 25: ...25 Connect cables to controls Left gang PP3 PP3 Switch Input Output Right gang ...

Page 26: ...t top gang and yellow is left gang A dual gang audio taper volume control is used type A10k Heat sleeve is provided to insulate conductors before installation Input from source Audio jack on PCB Wiper on PCB Ground connection Left gang Right gang ...

Page 27: ... the input and output Is marked with a dot for the right channel See H3 and H4 You will have to measure in the tin for cable lengths as per your position choice When connected to the sockets and switch place Prestik under the PCB and secure to the tin on the vinyl After all cables are connected clean the PCB with benzine and a toothbrush to remove flux ...

Page 28: ...28 LED window drill with a 1 mm drill this to suit your taste and also enclosure Mark and drill a small 1 5 mm hole for LED above the switch allowing a small clearance ...

Page 29: ... ALWAYS SWITCH ON WITH THE VOLUME CONTROL AT MINIMUM TO AVOID HEADPHONES DAMAGE Download a cell phone app that shows left right audio and plug in a aux cable to the side Plug in headphones Check left right this will show that the system works If not correct change the left right audio output cable to suit Note we have seen some aux cables with left right swopped over so always check with the inten...

Page 30: ...30 Before closing the lid ensure nothing fouls fit knobs and you are good to go ...

Page 31: ... work together So in this project we call it OP Amp rolling but we don t roll them we unplug them It s a great place to start at minimum expense Just remember a 8 pin dual channel jfet op amp in the specs As the Op Amp drives the headphone direct we have included a 10r audio grade resistor for the optimum experience Lets cite some examples TL072 It s a audio grade Op Amp from the 80s and in itself...

Page 32: ... will provide many hours of listening pleasure it is supplied With a TL072 op amp this may be improved on with different types of Op Amp thus changing the sound characteristics to suit your taste Enjoy Kwela Tones P Lintott www lintaudio co za June 2020 Lintaudio Let the hobby begin ...

Reviews: