Related Manuals for madbeanpedals Dirtbag deluxe
Summary of Contents for madbeanpedals Dirtbag deluxe
- Page 1 Dirtbag deluxe 11.2011 madbeanpedals Revised 12.12.11 – see page 5 PCB Dimensions: 3.2”W x 3.3”H...
- Page 2 Resistors Resistors Caps Caps Diodes R1 2M2 R32 100k C1 100n C32 22uF D1 LED R2 100k R33 16k C2 27pF C33 470n D2 1n914 R3 22k R34 16k C3 1n2 C34 47n D3, D4 1N4001 R4 100k R35 33k2 C4 47uF ...
- Page 4 What Is It? The DirtBag Deluxe (based on the EHX Deluxe Memory Man™) allows you to build what is probably the most loved bucket brigade delay of all time. It offers around 550ms of pure analog delay with the addition of chorus or vibrato modulation. The Dirtbag also incorporates modern accoutrements via true bypass operation, centerpin negative 9 – 15vDC operation and the ability to use different version of currently available BBD chips. WARNING: This is an incredibly difficult project. This is not a “first time” build by any means. Do not take on the DirtBag unless you feel confident in your abilities, or you may end up wasting quite a bit of time and money! That said, if you take your time and follow the instructions carefully, you should be able to get the DirtBag working with relative ease. Development of this project took place over several months, and should be relatively bugfree despite its complexity. Special thanks to forum member Scruffie and FSB member Dirk Hendrik who provided information and feedback during this process. Controls Level This adjusts the amount of gain at the input stage of the circuit. Blend – This controls the amount of delay signal mixed in with the signal from the input stage. Delay – The overall delay produced by the two series BBD devices. Counterclockwise is slapback and full clockwise should yield about 500 – 550ms of delay. Fdbk – This is the amount of delay signal fed back to the input of the delay chain. It controls the number of delayed repeats, Mod – This sets the overall modulation of the delay signal. Counterclockwise is no modulation. CH/VB – Stands for Chorus/Vibrato. This SPDT switch sets the type of modulation used by the Mod control. Chorus produces a very pleasing, spatial spread to the delay signal. Vibrato yields shorter pitch shifting around delayed notes. At low Mod settings, the modulation is both subtle and musical. At high Mod settings, the modulation becomes very intense and will produce some wild “seasick” type effects. Notes The DirtBag Deluxe can be built with three different types of BBD devices. The first is the MN3005, which were used in the vintage Deluxe Memory Man. Second is the MN3205, which have lower current consumption and different power requirements than the MN3005. Finally, the DirtBag can be built with the Coolaudio pinforpin clone of the MN3205: the v3205. These are readily available and used in a number of modern analog delay pedals. The bad news is that the MN3005 and MN3205 are scarce; much more now than just a couple of years ago. It’s a good bet that if you do not already have some of these in your possession, then you will have a very difficult time locating genuine chips. There are many counterfeit and relabeled chips being sold on eBay and elsewhere that purport to be MN3005 (or 3205). For this reason, I recommend not buying these from unknown or overseas vendors on eBay unless you have good reason to believe they are genuine. You may be able to get some through members of the DIY community or an international broker like UTSource. However, even UTSource has sent out some fakes (most likely unknowingly) in the past. The good news is that even in the absence of the MN3005 and MN3205 you can still build a totally righteous analog delay with the v3205. These are easy to get, and can be purchased from smallbear or similar vendors for about $4.50 each. What’s the difference? Do the different chips sound different? Yes. They sound different; but, only a very little bit. The biggest difference isn’t really in the actual technology behind the chips, but more likely in the voltage that runs them. The MN3005 can be run off 15v and the MN3205 and v3205 must be powered under 9v to operate properly. The added headroom allowed by running both the BBD and rest of the delay circuit ...
- Page 5 IOW: don’t sweat it! Build the version with the parts you can get and forget about it. If you like the way the Memory Man sounds then you will love the DirtBag Deluxe. If you plan on building the MN3005, you will need to utilize a Road Rage board, or similar charge pump design, to supply the board with 15vDC (regulated) instead of 9v. Please refer to the Road Rage documentation on the Projects page of the madbeanpedals website for more info. You should use an LT1054 charge pump and an LM7815ACT or similar regulator (the T0220 type which provides up to 1A of current). REVISION (CRITICAL): Some builders of the v3205 version of this project have run into distorted repeats. There is a simple solution to this issue. Replace R21 (1k) with 100k and C14 (33n) with another 100k resistor. This forms a voltage divider which eliminates overloading the lower headroom of the v3205. The original 1k/33n forms a low pass filter with a corner frequency of about 4825 kHz. Even though this fix eliminates this filter, it seems that the low overhead of the v3205 does not impact the delay tone in a significant way. Further tests also found that R10 could be omitted from the compressor portion of the NE570, but this is not critical. As a reminder, you will want to use 47k for both R11&R12 when building the v3205 version. Let’s Build It There are three jumpers to set on the board under IC5 depending on which BBD you are using. Note that you don’t want to mix and match BBDs. You need to use two MN3005, two MN3205 or two v3205 devices. MN3005 v3205 (MN3205) These jumpers connect the VDD, ground and VGG pins of both BBDs to their proper sources simultaneously. The MN3005 takes the VD voltage on pins 1, ground on pin5 and VGG is connected to ground on pin8. For the v3205, pin1 connects to ground, pin5 connects to approximately 8.2v (VD) set by D5 and VGG is about 14/15 of the VD voltage through the voltage drop over D2. Note that if building the MN3005, you should omit D5 from the board. The 8.2v Zener is only used for the v3205/MN3205. You should also omit D2 and C17. After setting the jumpers, I recommend populating the board with all the resistors IN ORDER. This will lessen the chance of placing the wrong value resistor in a place that could later cause problems. Solder the resistors in place on the bottom of the board. Note that for the MN3005, R11 & R12 need to be 68k. For the v3205/MN3205 they should be 47k. If you want to go the extra mile you can topsolder the resistors, too. This is not necessary for the effect to function properly provided you have used good technique on the bottom side, but it does lend itself to a more professional look.
- Page 6 Just be careful not to apply too much solder or heat to the pads as this will result in large solder bulbs or potential component damage. After the resistors, place all the IC sockets and trimpots on the board and solder in place. Take a little break…no kidding. Finally, place the remaining components, the film and electrolytic caps, diodes and transistors and solder them in place. Expect to spend 23 hours on this process….there are a lot of parts An important note on some components: Extra care should be taken with C41, the 240pF cap used to set the clock signal on IC9. You want to use as close to 240pF as possible. Note that many ceramic caps measure well under their stated values. If you have a multimeter that reads capacitance, measure a few out and pick the best one. You can also add different value in parallel to get close to the 240pF value (remember parallel caps result in the sum of their individual values). If you don’t have a capacitance meter, consider using a Silver Mica cap here instead of ceramic. You can always socket C41 and use what you have on hand. After biasing the BBDs (details below) you can go back and drop different 240pF caps in to see if they increase the delay time at all. Similarly, before soldering the PCB mounted pots measure the resistance between lugs 3&1 of several 100kB pots and pick the one closest to the actual 100k value. Use this one for your Delay pot. Again, this will give you the widest range of delay time. Now that you have that sorted out, load your pots and switch on the PCB and solder them up. Note that this PCB allows for 16mm shortpin PCB mounted pots underneath the board, and a solder lug SPDT switch (also mounted under the board). One last thing before moving onto biasing: D1 is the “overload” LED. This LED will give you visual feedback on the amount of signal coming off the first couple of gain stages of the effect. The higher the Level pot is set, the brighter the LED blinks. This can be soldered in pace (just above C45) or you can run wires from the board to the LED for different placement locations. If you do not wish to use the “overload” LED (it’s mainly a visual effect) you can omit R18, C13, R19, Q1 and R20 from the PCB along with the LED. Biasing Biasing the Dirtbag for operation is actually pretty easy and can be done without a scope. You will need to use an audio probe. Before connecting the board up, set the BIAS1, BIAS2 and BAL trimmers to their middle positions. Set the GAIN1 and GAIN2 trimmers fully counterclockwise. Finally, set the Level somewhere in the first have of its rotation, Blend about ¼ up, Delay about halfway up, Mod fully counterclockwise and Fdbk to about the middle. Now connect the input from your guitar (or signal generator), the output to your amp and power up the board with your power supply (make sure you have a common ground connection). Test to see if you are getting signal through the effect. You may or may not hear any delay at this point. You should be able to hear volume changes when increasing or decreasing the Level control. If you do not get any signal through, recheck your connections and make sure there are no errors in your build. Once you have verified the passthrough signal, disconnect the output to your amp and connect your audio probe to the amp. Now you will be able to probe the audio signal on the board wherever you place the probe tip. Probe pin3 of IC4 while sending some signal through. Adjust BIAS1 until you get the cleanest delayed signal possible. Repeat the same process with pin3 of IC5. Adjust BIAS2 until you get the cleanest delayed signal possible. You should be able to leave the BAL trimmer in its middle position. ...
- Page 7 Note this is the “layman’s way” of biasing the DirtBag and it works quite well. If you wish to use a scope to professionally configure its operation please take the time to Google the factory set up guide for the Deluxe Memory Man. You should be able to find information on both the EHX website and some on FSB. Wiring This is the wiring for the MN3205/v3205 version. If you are building the MN3005 version, you need to use a Road Rage (or similar charge pump design) for 15v operation. Please refer to the Road Rage documentation for information on building the charge pump. The green circles indicate ground pads. You do not have to use all of them. They are there for convenience.
- Page 8 Drill Template 1590B 5.8”W x 6.8”H @ borders This template is approximate. Please check carefully before committing to drilling your enclosure Licensing The user may utilize a purchased DirtBag Deluxe PCB from madbeanpedals for DIY/noncommercial purposes. You may not use the artwork to sell your own version of the PCB design or as part of a “kit” or similar commercial product. www.madbeanpedals.com...
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