Myriad Design Altoids Piezo DI Construction Guide

Transcription

1 Myriad Design Altoids Piezo DI Construction Guide V2 December, The package should include the following items. If any of the items are missing from the package, please contact : Designation Description Marking PCB Altoids 1 Piezo DI - printed circuit APDV4DS06 board R1, R5, R6 1/8W resistor - 10k See Note 2 R2 1/8W resistor - 10M R3 1/8W resistor - 4k7 R4 1/8W resistor - 1M0 R7, R8 1/8W resistor - 33R R9, R10 1/8W resistor - 1k0 R11 1/4W resistor - 10R R12 1/8W resistor - 180k R13 1/8W resistor - 120k R14 1/8W resistor - 220k R15 1/8W resistor - 150k R16 1/8W resistor - 3k6 C1, C6 22p ceramic 22 C2 470p ceramic 470 C3 47n polyester box 47n or.047 C4, C5, C9, C12, 100n polyester box 100n or.1 C13 C7, C8 47u 50V electrolytic C10, C10, C11, 100u 50V electrolytic C11 C14 10n ceramic 10n or 103 D1, D2, D3, D4 1N4148 diode 1N4148 D5 BZX55C33V BZX55C33 Q1, Q2 PF5102 JFET matched pair PF5102 U1 LM833 dual op-amp LM833 U2 TC54VN2902EZB voltage detector 54VN2902 LED1 3mm red LED - Battery Clip J1, J2 1/4 stereo jack socket CL11155 SW1 push-on push-off switch - 8-pin DIL socket - green wire - card with self-adhesive tape/foam - self adhesive foam pad - M3 x 6 pozi pan machine screw - M3 brass nut - label for underside of Altoids tin - template drawing for cutting holes - quick start guide 1 Altoids is a trademark of the Wrigley Company. Their rights are hereby acknowledged. 2 Some resistors may be 4-band and some 5-band. See: 2. It is assumed that you have some experience of soldering and building of simple kits and are confident to build or modify effects pedals. If not, there are many relevant tutorials and videos on Page 1 of 6

2 the internet. Please spend some time familiarising yourself with construction and soldering techniques. 3. Note that Q1, Q2, D1~ D5, U1 and U2 are electrostatic sensitive devices and should be handled with care. If you have an ESD protective wristband, use that. If not, wear clothes made of natural materials (e.g. cotton), regularly touch your finger to an earthed (grounded) metal object (such as a radiator) and do not handle the sensitive devices any more than you have to. In particular, don t remove them from the electrostatic protective package until you are ready to fit them to the board. 4. Solder the items to the PCB according to the silk-screen legend, checking and ensuring that you insert each component in the correct orientation. Page 2 of 6

3 5. Note that if you are not using an Altoids tin as an enclosure and you wish to have a volume control on the output, then omit LK3 and fit a potentiometer (not supplied) to the VR1 connections. The clockwise end of the potentiometer is marked on the PCB CW. 6. Note that LK2 is fitted after the battery clip has been soldered in - and serves to act as a strain relief. 7. Note that the LED must be connected the correct way round. The shorter lead of the LED is the cathode and is shown by the flat side of the PCB legend. If you have cut the leads of the LED and lost track of which was the shorter lead, look inside the LED the cathode is the larger of the two internal structures (note that this is not a universal rule). 8. There is no compelling reason to cut the green earth wire short and you will find it easier to solder the wire to the enclosure if you leave the green wire fairly long. 9. You may wish to test the board before installing it in the enclosure. The input and output sockets are clearly marked on the board. The battery is not connected to the circuit until there is a plug in the input socket. Connect the input to an instrument with a piezo transducer (or indeed any instrument, including electro-acoustic guitar, electric guitar, bass guitar, or even a keyboard, etc). Connect the output to a mixing desk with phantom power. With the switch in the out position, the unit will be phantom powered. With the switch in the in position, the unit will be battery powered. Enclosure 10. Carefully remove the lid of the Altoids tin by bending back the hinge tabs. Cut out the template and stick it on to the tin ensuring that the template is centred. Cut out the holes for the switch, LED and Jack sockets. Take care cutting the larger holes as a normal 10mm HSS Drill bit will likely tear the thin metal. The use of a stepped sheet-metal drill (Google: step drill) or a Q-max chassis punch (Google: q-max 10mm) is recommended. Refit the lid and drill a 3mm hole half way along the lidflange at the front for the screw. Page 3 of 6

4 11. Remove the lid again and screw the nut and screw through the tin. Solder the nut to the case. Note that a 25W soldering iron with a 3mm or larger tip is adequate. 12. Remove the brown cover tape from the underside of the cardboard insulator and carefully fit it to the bottom of the tin. The foam pad should be at the end opposite to the holes. There is no need to remove the backing paper from the top of the foam pad if you stick the battery down to the pad, it will be useless when you change the battery. 13. Carefully solder the end of the green wire to the inside of the tin. Note that the accompanying photo shows a black wire in lieu of the green wire supplied. 14. If you have not already done so, carefully clip all the protruding pins on the rear of the circuit board. In particular, the pins on the sockets should be trimmed back as short as possible. You can use the supplied sticky foam pad to stick the board down (as shown in the photograph below), but longterm experience is that you will be better off gluing the board in place with a little hot-glue, silicone or instant-grab adhesive. 15. Fit the lid and bend the tabs back in place to ensure the lid stays on at the hinge side. Fit the battery, allowing the battery wire to fall across the top of the battery. Close the lid and fit the screw. Lightly shake the unit; the battery should not rattle around. 16. Carefully apply the sticker to the underside of the tin. Page 4 of 6

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6 17. Note: the reason a stereo jack socket was used on the input side is so that the unit may be switched off when the input cable is removed. 18. Note: the power consumption of the unit is a few milliamps. This means that a fresh alkaline battery will last a few weeks to a few months of moderate use. Try to power the unit from a phantompowered mixing desk if possible. 19. You will need to make/buy a special output lead for this unit. I suggest a length of about 2 metres with a stereo ¼ jack plug one end and a 3-pin male XLR the other end. Connect the tip to pin 2, the ring to pin 3 and the sleeve to pin 1. You should then tell the sound guy that you need a microphone lead with phantom power for your preamp DI. Keep the short custom lead with the unit so you always have it wherever you go to gig. Alternatively, you can make the lead as long as you like (i.e. to go straight to the mixing desk), or make a very short adapter lead, but if you make the lead too short, the weight of the cable with two XLRs dangling off your back pocket (assuming that s where you stash your unit when in use) can be a little annoying. Using the Preamp DI 20. The preamp has very high input impedance. This makes it suitable for passive piezo pickups which may be built-into or added on to stringed or percussion instruments. Generally speaking the cable between the pickup and the instrument should be as short as practical - if you are a violin player you should consider having a lead from your pickup just long enough to comfortably reach the preamp if the preamp is in the back pocket of your jeans or in a pouch slung over the shoulder. The output cable can then be as long as it needs to be to reach the mixing desk or mixer-amp. 21. The preamp may also be used with other types of pickup. For example, you can use it to DI an electro-acoustic guitar or even a keyboard. In fact you can think of it as a general purpose instrument D.I. with the caveat that the DI needs ideally to have a short lead to the instrument. 22. You should disconnect the input cable when the preamp is not in use as this will disconnect the battery and conserve battery life (this is obviously not important for phantom power use). When the battery voltage drops (from 9V) to about 7.3V the LED will illuminate. As the consumption is fairly high (several ma) you should replace the battery (or switch to phantom power) as soon as you notice the light coming on. Note that the low battery light will come on even if you are on phantom power, so you may not need to worry. If you re always going to be on phantom power, you can omit the battery altogether. Copyright Myriad Design. All rights reserved. Disclaimer. The information contained herein is provided in good faith. Myriad Design has no control over the standard of construction of this kit, nor any control over the way the design is implemented or integrated into a system. Therefore, Myriad Design offers no actual or implied warranty of fitness for purpose and Myriad Design will accept no liability for consequential loss or damage. This design is not authorised for use in any safety-critical system. Your statutory rights are not affected. Myriad Design United Kingdom sales@stompville.co.uk Page 6 of 6

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