[sdiy] Boss/Roland Dimension C/D differences

[Seb Francis]

It's interesting that you say the mode 4 is different between the 2.  I 
wonder which sounds 'better' (subjective term that!)

The Dim D was released in 1979 and the Dim C not until 1985, so perhaps 
they had refined the sound in this later edition - but more likely it 
was changed either to tailor more for guitars or to get component count 
down.

I am toying with the idea of adding fully variable controls to set the 
chorus parameters, but then again half the beauty of the Dim C/D is that 
the sound is 'just right' without having the play around.  Perhaps 5 
buttons would be good - including both mode 4s from C & D.

Seb


Scott Stites wrote:
> Hi Seb,
>
> I've been slowly circling the Dimension D myself lately, intending a build.
>
> Some differences between the two:
>
> The Dimension D provides stereo output of either a mono or stereo input.  The Dimension C provides stereo or mono output of a mono input (my Dim C has been modified to provide stereo inputs as well).
>
> The Dimension D will certainly have scads more headroom.
>
> >From what I can tell, the two produce Mode 4 differently.  In the Dimension C, Mode 4 is just another LFO frequency/depth combination.  The Dimension D appears to use the same LFO frequency/depth as Mode 3, but instead changes the amount of direct wet signal to each channel, without modifiying the crossfeed delay level.
>
> The Dim D uses a boatload of HA1457 preamp IC's, that are (over here anyway) nearly pure unobtainium.  There's a PNP in the output section that is also difficult to find here (though the NPN can be acquired quite easily). 
>
> I'm interested in building a Dim D, but I'm going to have to do some part substitutions.  The one thing I'd really be prone to try is a mono output mode, implemented in the way it is done in the Dim C.  The mono output on the Dim C is a fantastically wonderful thickening agent.
>
> Cheers,
> Scott
>
>
>
>
> -----Original Message-----
>   
>> From: Seb Francis <seb at burnit.co.uk>
>> Sent: Apr 17, 2006 7:17 AM
>> To: Synth DIY <synth-diy at dropmix.xs4all.nl>
>> Subject: [sdiy] Boss/Roland Dimension C/D differences
>>
>> Well, 1 project almost wrapped up, so it's time to start on another :)
>>
>> I want to build a clone of the Roland SDD-320 "Dimension D".  I have the 
>> schematics of the Dimension C guitar pedal but I can't find the 
>> schematics of the Dimension D anywhere.  I'm wondering if it's worth 
>> buying the service manual from Roland, or should I just work from the 
>> Dimension C schematics .. are these things essentially the same?
>>
>> I know the Dimension D has stereo line level inputs as opposed to mono 
>> guitar level input, and it has LED level meters.  But I'm not sure about 
>> any other differences?  Would anyone care to share the schematic of the 
>> Dimension D input stage?
>>
>> TIA,
>> Seb
>>
>>
>>
>>     
>
>
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