Boss DD-5 "analog" (hi-cut) mods: the final word?

[ESPm2M]

I have been through the previous relevant threads and, assuming I didn't miss what I was looking for, no one seems to know how to do the hi-cut mods on a DD-5, save AnalogMike w/ his proprietary method. Whenever someone starts a thread on this topic invariably someone chimes in with the hi-cut mods that work for the DD-2/3 - these do not work with the DD-5! Apparently the pots on a DD-5 alter control voltages for certain chips on the board rather than being direct "definers", if you will.

Have there been any developments in discovering a way to do this mod properly on a DD-5, be it on the overall blend section or the feedback section (ideally both)?

I would be actively investigating methods myself if I knew what I was talking about! -Unfortunately I'm a hobbyist, not an EE.

I look forward to comments.

A safe St. Patties to all!

[cd]

To get you started, you have to realize why the DD2/3 method doesn't work on a 5/6.  The 2/3 are setup much like an analog delay, except the delay line is digital; that is, feedback is controlled with a pot and the signal is sent back into the delay line again and again, just like an analog delay.  Which is why you can stick a cap on the pot to cut highs.  The 5/6 simply tell the delay chip to spit out another copy of the signal, while the pot/knob controls the delay chip.  There's no "direct communication" if you will.

SO, on the 5/6, all you have to do is find out where the copies get spit out again/again/again and filter that.  I forget where this is exactly on the 5/6, but your best bet is to probably dink with the LPFs that come before the mixer (the LPFs that remove the digital clocking noise).  They already cut high end, so if you want to cut some more, you can do it with a couple simple part changes.

If you want to learn more on analog delays (which applies generally to the 2/3) there's an article on the Midwest Analog site on building your own analog delay (I don't recommend trying to build it since the parts are scarce):

http://www.midwest-analog.com/diydel.html

It gets into the nitty gritty of how an analog delay works.  The DD2/3 works much the same way, except the delay line is digital.

[Maneco]

I've sen the dd5 schematic,and the mixing/feedback stage is analog,so the hi cut mod works ,just by adding a cap in the pot...i used to think the mixing was digital,but i was wrong...

[TheBigMan]

I've done it, the same hicut mod as the DD-2/3 works on the DD-5 as well.  There is/was a thread in the archives by Ian87 IIRC who said he had done it as well.

[Maneco]

update...
i opened mine,and found that the feedback pot is a rotary encoder,and the volume pot is a stereo one,so you have to put condensers across both sections of the volume pot...the pot is 10k stereo...
btw,the dry cut mod is done by removing c9, a 3.3uF surface mount,that can be subbed by a switch and a 3.3 uF non polarized...that is useful in the reverse mode...

[cd]

update...
i opened mine,and found that the feedback pot is a rotary encoder

Which is why sticking a cap across it like with the DD2/3 won't work.  In fact there's already a large value cap across that pot.  You either have to do on the volume pot (like you mention) or in the mixer.

[cd]

Oh yeah, here's that thread, as usual Mark Hammer is way more eloquent than I could ever be:

http://www.diystompboxes.com/sboxforum/viewtopic.php?t=19237

[cd]

I don't suppose anyone has a more complete DD-5 schem, one where the left side is not cut off?

[putrefusion]

this is a good thread!  bookmarking...  

[beedoola]

so does anyone have any new info on this? I'd love to do the hi-cut mod on my DD-5.

Also, does the mod affect the tone of the HOLD function at all?

[beedoola]

bump

[beedoola]

bump again. Anyone have any info on the mod?

[slacker]

What do you want to know?

You can do what Maneco said 10 years ago "and the volume pot is a stereo one,so you have to put condensers across both sections of the volume pot." which will reduce the treble in all modes, you'll need to experiment with capacitor values to find something you like.

[beedoola]

What do you want to know?

You can do what Maneco said 10 years ago "and the volume pot is a stereo one,so you have to put condensers across both sections of the volume pot." which will reduce the treble in all modes, you'll need to experiment with capacitor values to find something you like.

I want to know what the Analogman mod consists of, if anyone has figured it out.