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.
C
H/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
at 15v (like the Deluxe Memory Man) can account for slight differences in tonality and warmth produced by the effect.
However, this difference is subtle and whatever added headroom one gains is always mitigated by the fact that analog
delay, at its core, is a sound degradation device. The purpose of analog delay is to destroy the purity of the input signal in
incremental bits over time. That is where the “warmth” of the effect is created.
Having built many analog delays with different BBD devices I can honestly say I like them all, and would happily use any
version I had available. The real magic in analog delay is how you interact with it. Finding the right delay time, repeats,
blend and modulation and playing off those dynamically is where it’s at: it’s not in the bits and pieces in the box.
