modifying the BBD-320 dimension chorus

The Klark Teknik BBD-320 purports to be a more or less faithful clone of the Roland SDD-320.  These are stereo analogue dimension chorus effect units, housed in 2U rack cases.  If you've followed my previous blog writings, you'll be aware that I just recently ran into a disappointing dead end with the TC Electronic 3rd Dimension pedal, which strongly postures itself as a clone of the Boss Dimension-C pedal, while coyly avoiding any explicit claim of such.  The Dimension-C is the Boss pedal-format adaptation of the SDD-320.  The 3rd Dimension has the same peculiar 4-button interface as the Boss unit, and it claims to produce a "motionless" chorus effect.  And after all, it has the word "dimension" in its name!  But, it's not a dimension chorus.  It has only one clock generator and BBD delay line, whereas two are required to produce a bona fide dimension chorus.  The 3rd Dimension is nothing but a standard chorus unit, dressed up like a Dimension-C.  The 3rd Dimension is significantly cheaper than the Boss units, and I guess their business model is to deceive hopeful musicians who want to save money: which is a shame.  Don't buy the TC Electronic 3rd Dimension.  If you want a regular chorus, buy the Boss CE-2 or any of dozens of other units, or use digital plugins, or whatever.  Regular chorus is a very easy effect to produce, and it is ubiquitous throughout the world of electric and electronic music.

So, having failed to obtain a real dimension chorus with the TC unit, I was left still searching for some alternative to the Boss pedals, which are rather expensive considering how simple their analogue BBD circuitry really is.  The original DC-2 pedal is no longer made; currently, used examples are going for about $170.  The newer Waza re-issue of the pedal, called the DC-2W, costs well over $200, and since schematics are not available for this pedal, I'm not sure if the modifications I want to make can be applied to this circuit (in particular, the preset buttons are now digital logic, not simple DPDT switches; I wouldn't be surprised if the entire LFO function is now produced by an MCU, that's probably how I'd do it!).

There's a company, Aion FX, which sells the circuit boards for a DIY dimension chorus, similar to the original Boss DC-2 except using currently-available modern parts in place of certain obsolete parts, and using through-hole chips exclusively, avoiding any surface-mount components.  It's a very nice set of boards, but unfortunately Aion does not offer a full kit; i.e., one is left to obtain the large number of components and the case on ones own.  Aion does include a parts list with manufacturer info for all the parts (most are available from Mouser).  The boards cost about $25, and Aion estimates that the rest of the parts will probably cost at least $100.  So, this is potentially slightly cheaper than the alternatives, but is hardly a "compelling price savings" like the TC 3rd Dimension appeared to be!

Behringer used to make a dimension chorus pedal, called the CC300, but this is out of production.  There's also a boutique company called Fromel Electronics, who used to make a pedal called the Seraph.  It seems this pedal may no longer be available new, and either way, it cost somewhere in the thousands.  Looks like a very nice pedal, though.  I've seen used examples of the Seraph going for the $250 range, and I'm sure they're worth it, but that's not the price point I'm looking for.  And I want to base my work on a unit which is currently in production, if possible.

 

Buying two TC Electronic 3rd Dimension pedals and interconnecting them to create one true dimension chorus effect, wouldn't be out of the question.  This would still be cheaper than buying one Boss pedal.  However, I found the audio quality of the TC unit to be wretched, with clearly-audible distortion.  That's why I don't recommend it, even as a regular chorus.

 

The original SDD-320, in addition to being out of production, now costs well over $1000!  Musicians are so easily seduced by the notion of "vintage mojo".  Sigh.

So, that brings us to the Klark Teknik BBD-320.  These are available for "only" $170, placing them right at the same level as a used DC-2 pedal, and significantly cheaper than the DC-2W.  And the rack unit provides several benefits over the pedal.  The BBD-320 is full-stereo, in and out, and it provides balanced XLR jacks as well as unbalanced 1/4".  It provides a handy 10-segment LED output level display on the front panel.  The excessively large 2U case is mostly empty, which certainly provides ample room for any mods I might wish to make.  It's a lot more money than I originally thought I was going to have to spend, to get a serviceable dimension chorus effect, but it looks like it may be the most cost-effective option available, and it certainly seems to be a fair price for what it is.

So, looks like my next move may be to order a BBD-320.  I guess I'm not as eager to pull the trigger on this as I was buying the under-$40 TC pedal, but I do have more confidence that the end result will be more satisfactory, so stay tuned...