Boss - DC-2 Dimension C  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.

Re: Boss - DC-2 ( Dimension C )

Postby jfromel » 24 Feb 2009, 09:01

Andre that is some really impressive work, I wish I would have known about this thread earlier I would have been contributing all along.

I make a clone of the DC-2 called the Seraph so I know this circuit inside and out.

A couple notes on the schem, the one published from Boss has pins 9 and 10 on IC2 connected, dont do that. The toppicone schem has the voicing for the mono/stereo as a hard switch, this can be done with the original circuit and still have the unit be ture bypass. On that note I am using a millinium bypass with a 3PDT switch for true bypass in stereo, very nice not to have to jack with a buffer or relay.

This circuit can sound a lot better than the DC-2.

1. Change the op-amps - I am using OPA-2134 in the input and output, TL072 in the BBD and TL062 in the LFO. I think Monte Alum has a 9pin to 8dip converter for swapping op amps if you want to use the DC-2 layout.
2. Use Mica's instead of ceramics, use EL's instead of the tants on the NE570's, use bi-polar EL's for all the 10uf caps, use film for all the 1uf caps.
3. C30 and C29 in series with anodes connected control the speed of the LFO, not sure why Boss didn't just use a 4.7uf BP but some cool changes can be had by altering these values. Lower values speed up the LFO. Try a 3.3uf BP across both for a slightly faster range or add a cap in parallel with a switch to give you more modes.
4. It's not all that hard to rig this for stereo in/out everything is already in place except for another input circuit before IC2 as the other half of the NE570 is unused.
5. With some changes to the power rail and beefing up IC10 to a 7806 this can be run as hot as 18v and the headroom is massive. Just need to make sure that all your caps are rated high enough and the op-amps you choose for the input/output stage can run that hot.
6. I have been using NOS BBD's, Clocks, and companders but I am going to pick up some of the cool audio repro's and see what I think. Malekko is using the 3205 in their delay and it sounds fantastic.

Someone mentioned a hiss on their toppicone layout clone... did you tune this up on a scope? Feed the unit with a sine wave between 1k and 10k (I use 8K). At TP1 adjust the trimpot for the first BBD line for zero distortion, you should be able to dial out the distortion while feeding it a signal hotter than line level. Repeat this for TP2. Use better OP-apms for IC5 and IC8, perhaps a TLC2272, it's rail to rail, fast stable and quiet. I have been using BC549 and BC559 for the trannies and they are fine, no need to go looking for SK30A's or whatever Boss used in the 80's

The PCB layout I designed for the pedal would not work for a etch your own DIY project, it's double sided with ground and power planes. I did make some DIY PCB's for a stereo in/out version that would make a realy huge pedal or nice rack unit, I think I have about 30 or so left.

If anyone has any questions on this or needs help just shoot me a PM.

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Re: Boss - DC-2 ( Dimension C )

Postby bajaman » 24 Feb 2009, 11:18

Thanks jfromel for some very interesting points - do you mean to run the opamps on 18v dc with a 9v centre rail? and the BBD chips from 6v dc?
cheers
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Re: Boss - DC-2 ( Dimension C )

Postby andre » 24 Feb 2009, 16:33

lohstah wrote:correction to my post: the noise is present in both the mono and the stereo outs.
it´s easy to hear it when ic12 is taken out, and only the (trebly) effected parts of the sound are heard; as i said, white noise and occasional clicks in time with the clock.
i went over the board again today, checked for the right cap values etc, no shorts...i think it might be the layout, with all those jumpers. somewhere the clock noise is getting in.

cheers,
lohstah


Lohstah,
For reference I will make some soundclips of my DC-2
Until now I don't think I've heard this noise you're talking of, but I will listen closely this evening.
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Re: Boss - DC-2 ( Dimension C )

Postby lohstah » 24 Feb 2009, 16:34

hey,

i´m the one with the hiss. it is in time with the rate setting, and there are occasional clicks and pops as well, so i´m convinced it does not come from the bbd bias setting. it is just like the normal dc-2 background noise (gotta listen with headphones very carefully to hear that one), but louder and coming+going in waves in time with the rate setting.
your suggestions about the ic´s and everything else are interesting, but first i have to get rid of the noise, if possible at all. i listened to morocotopo´s soundsamples on the other forum, and as far as i can hear (he does not let notes ring long in his sample), he has the same noise, so i think it really is the layout. i contacted him, waiting for his answer.
at the moment, i have tl072´s in there, with a tl062 for the lfo. i´ve also been toying around with different ic´s for the lfo, tl022 does not make it quieter (should have the least current draw). when i used a lm358n, the lfo did not work, and the noise was also almost gone, so that does sound very much to me like the lfo bleeds into some other line somewhere. but where ? that layout is so damn big, i don´t wanna shield all the jumpers to later find out that the pcb traces themselves are picking up the noise.

cheers,
lohstah
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Re: Boss - DC-2 ( Dimension C )

Postby lohstah » 24 Feb 2009, 16:36

Lohstah,
For reference I will make some soundclips of my DC-2
Until now I don't think I've heard this noise you're talking of, but I will listen closely this evening.


thanks, but, as you did the layout according to the dc-2, there probably will be none. i have an original here at the moment, and it is very quiet.

but thanks anyway !

cheers,
lohstah
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Re: Boss - DC-2 ( Dimension C )

Postby andre » 24 Feb 2009, 16:44

jfromel, thanks indeed for your suggestions.
I will remove the connection between pins 9 and 10 of IC2.
I'm not sure if these 9pin to 8dip converters will fit in the enclosure I used.

André
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Re: Boss - DC-2 ( Dimension C )

Postby andre » 25 Feb 2009, 10:02

I checked my DC-2, but it does not have pins 9 and 10 of IC2 connected, so while the orignal schematic is wrong, the original PCB is OK.
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Re: Boss - DC-2 ( Dimension C )

Postby jfromel » 26 Feb 2009, 02:21

lohstah wrote:hey,

i´m the one with the hiss. it is in time with the rate setting, and there are occasional clicks and pops as well, so i´m convinced it does not come from the bbd bias setting. it is just like the normal dc-2 background noise (gotta listen with headphones very carefully to hear that one), but louder and coming+going in waves in time with the rate setting.
your suggestions about the ic´s and everything else are interesting, but first i have to get rid of the noise, if possible at all. i listened to morocotopo´s soundsamples on the other forum, and as far as i can hear (he does not let notes ring long in his sample), he has the same noise, so i think it really is the layout. i contacted him, waiting for his answer.
at the moment, i have tl072´s in there, with a tl062 for the lfo. i´ve also been toying around with different ic´s for the lfo, tl022 does not make it quieter (should have the least current draw). when i used a lm358n, the lfo did not work, and the noise was also almost gone, so that does sound very much to me like the lfo bleeds into some other line somewhere. but where ? that layout is so damn big, i don´t wanna shield all the jumpers to later find out that the pcb traces themselves are picking up the noise.

cheers,
lohstah


IIRC the toppicone layout has a few jumpers and that could be causing noise to be introduced, try running shielded wire on the jumpers especially any close to the LFO, be sure to ground the shield.
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Re: Boss - DC-2 ( Dimension C )

Postby lohstah » 26 Feb 2009, 17:13

i shielded some of the jumpers today, plus substituted 1 pcb track with shielded wire (cutting the pcb tracks). mostly directly around the lfo, IC7/3 to IC5/3, IC5/1 to R48, Q4 to IC11/13 (+9V), R24/Q4 to C19, R70/C44 to C46, pcb track IC7/3 to C36.
did not help the noise at all.
maybe i´ll continue tomorrow, i stopped now because i´m getting pissed. :twisted:

cheers,
lohstah
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Re: Boss - DC-2 ( Dimension C )

Postby Krinkle » 05 Mar 2009, 19:14

audiohub wrote:
nooneknows wrote: a bit OT:

Krinkle wrote:
I started by buying the Behringer clone pedal, the Chorus Space-C CC300, then liked it so much that was the end of the project!


I bought one as it got out too: awesome. IMHO very similiar in sound to the DC-2, at least as I remember it ( a friend of mine got one long ago). BTW, 26 Euro...


I just got one of these Behringer CC300's in today to examine the possibility of modifying it for TZF, and after spending a half hour under the microscope, it appears to be a SMD recreation of the Boss DC-2 in almost every aspect. It's based on the Cool Audio Chipset using a pair of V3207/V3102 BBD's and clock drivers, and a pair of V571 compander chips.
Audio is handled by a quad TL064 chip, and LFO and clock voltage summing by a pair of V4558's.
The board is small and packed with SMD on both top and bottom, and both component number AND VALUE are silkscreened by each component, making it fairly easy to trace it's lineage.
I think that there may be a few different resistors in their preset selections, which might explain why some people feel that this unit has a less "subtle" effect than the Boss. Everything I've traced in the audio path so far has been true to the DC-2 schematic.
The only thing that they could have done to make tracing any easier would be to make each component number match up with the Boss...not the case, unfortunately :)

Oh, and did I mention that it was $29 delivered to my door, and sounds great, especially in stereo?
Clean and quiet, with great preset examples of the Boss "motionless chorus" effect.
The case is plastic with a fairly heavy metal bottom to give it a bit of heft, and the jacks are cheesy plastic with metal insert sleeves.
Switching is electronic, but seems to work well.
This seems like a great value, and it could certainly be re-housed if desired. Also seems like it's ripe for mods by those with tiny SMD experience.


Don't worry, people with the originals that sell for twice the value on eBay will explain to you why they are no good. Perceived input distortion, lack of headroom, new chips can't possibly be as good as the old ones (they didn't use any test equipment but that's okay because they modded their ears with the "Spectrum Analyzer Mod" - NOS ear parts from vintage cadavers by God electronics), and if all else fails no "bloom" (my favorite word from somebody who just paid way too much for a boutique or vintage piece of equipment).
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Re: Boss - DC-2 ( Dimension C )

Postby jfromel » 05 Mar 2009, 19:49

Krinkle wrote:
audiohub wrote:
nooneknows wrote: a bit OT:

Krinkle wrote:
I started by buying the Behringer clone pedal, the Chorus Space-C CC300, then liked it so much that was the end of the project!


I bought one as it got out too: awesome. IMHO very similiar in sound to the DC-2, at least as I remember it ( a friend of mine got one long ago). BTW, 26 Euro...


I just got one of these Behringer CC300's in today to examine the possibility of modifying it for TZF, and after spending a half hour under the microscope, it appears to be a SMD recreation of the Boss DC-2 in almost every aspect. It's based on the Cool Audio Chipset using a pair of V3207/V3102 BBD's and clock drivers, and a pair of V571 compander chips.
Audio is handled by a quad TL064 chip, and LFO and clock voltage summing by a pair of V4558's.
The board is small and packed with SMD on both top and bottom, and both component number AND VALUE are silkscreened by each component, making it fairly easy to trace it's lineage.
I think that there may be a few different resistors in their preset selections, which might explain why some people feel that this unit has a less "subtle" effect than the Boss. Everything I've traced in the audio path so far has been true to the DC-2 schematic.
The only thing that they could have done to make tracing any easier would be to make each component number match up with the Boss...not the case, unfortunately :)

Oh, and did I mention that it was $29 delivered to my door, and sounds great, especially in stereo?
Clean and quiet, with great preset examples of the Boss "motionless chorus" effect.
The case is plastic with a fairly heavy metal bottom to give it a bit of heft, and the jacks are cheesy plastic with metal insert sleeves.
Switching is electronic, but seems to work well.
This seems like a great value, and it could certainly be re-housed if desired. Also seems like it's ripe for mods by those with tiny SMD experience.


Don't worry, people with the originals that sell for twice the value on eBay will explain to you why they are no good. Perceived input distortion, lack of headroom, new chips can't possibly be as good as the old ones (they didn't use any test equipment but that's okay because they modded their ears with the "Spectrum Analyzer Mod" - NOS ear parts from vintage cadavers by God electronics), and if all else fails no "bloom" (my favorite word from somebody who just paid way too much for a boutique or vintage piece of equipment).


I haven't played the Behrringer one but there is a lot that can be done to make the original DC-2 sound much better and have way more headroom. It's no secret mojo sauce, just use better quality components and it sounds better. I am using NOS chipsets in my chorus but I want to try some of the cool audio chips, so far the reviews are good and the delay chip in the Malekko 600B sounds great.

I have an original DC-2 here and if the local music store has a Behrinnger I will pick one up and put them both on the scope, I don't have a Spectrum Analyzer with the NOS ear parts but I do have a nice oscilloscope and sig gen.
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Re: Boss - DC-2 ( Dimension C )

Postby lohstah » 05 Mar 2009, 20:26

that some action is happening in this thread reminds me of the fact that i´m getting nowhere with that bloody critter. the jumpers i shielded so far did not help, what did help (but only a tiny bit) was cutting that one trace from the lfo down the board to the clock ic´s. i think the lfo is placed very unluckily in the topo layout, right next to the power section and far away from the bbd´s. the original has the lfo right in between the two bbd lines. maybe i should make a daughter board, just for the lfo, and use shielded wire to connect it to the motherboard ?

cheers,
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Re: Boss - DC-2 ( Dimension C )

Postby Krinkle » 06 Mar 2009, 14:43

jfromel wrote:
Krinkle wrote:
audiohub wrote:
nooneknows wrote: a bit OT:

Krinkle wrote:
I started by buying the Behringer clone pedal, the Chorus Space-C CC300, then liked it so much that was the end of the project!


I bought one as it got out too: awesome. IMHO very similiar in sound to the DC-2, at least as I remember it ( a friend of mine got one long ago). BTW, 26 Euro...


I just got one of these Behringer CC300's in today to examine the possibility of modifying it for TZF, and after spending a half hour under the microscope, it appears to be a SMD recreation of the Boss DC-2 in almost every aspect. It's based on the Cool Audio Chipset using a pair of V3207/V3102 BBD's and clock drivers, and a pair of V571 compander chips.
Audio is handled by a quad TL064 chip, and LFO and clock voltage summing by a pair of V4558's.
The board is small and packed with SMD on both top and bottom, and both component number AND VALUE are silkscreened by each component, making it fairly easy to trace it's lineage.
I think that there may be a few different resistors in their preset selections, which might explain why some people feel that this unit has a less "subtle" effect than the Boss. Everything I've traced in the audio path so far has been true to the DC-2 schematic.
The only thing that they could have done to make tracing any easier would be to make each component number match up with the Boss...not the case, unfortunately :)

Oh, and did I mention that it was $29 delivered to my door, and sounds great, especially in stereo?
Clean and quiet, with great preset examples of the Boss "motionless chorus" effect.
The case is plastic with a fairly heavy metal bottom to give it a bit of heft, and the jacks are cheesy plastic with metal insert sleeves.
Switching is electronic, but seems to work well.
This seems like a great value, and it could certainly be re-housed if desired. Also seems like it's ripe for mods by those with tiny SMD experience.


Don't worry, people with the originals that sell for twice the value on eBay will explain to you why they are no good. Perceived input distortion, lack of headroom, new chips can't possibly be as good as the old ones (they didn't use any test equipment but that's okay because they modded their ears with the "Spectrum Analyzer Mod" - NOS ear parts from vintage cadavers by God electronics), and if all else fails no "bloom" (my favorite word from somebody who just paid way too much for a boutique or vintage piece of equipment).


I haven't played the Behrringer one but there is a lot that can be done to make the original DC-2 sound much better and have way more headroom. It's no secret mojo sauce, just use better quality components and it sounds better. I am using NOS chipsets in my chorus but I want to try some of the cool audio chips, so far the reviews are good and the delay chip in the Malekko 600B sounds great.

I have an original DC-2 here and if the local music store has a Behrinnger I will pick one up and put them both on the scope, I don't have a Spectrum Analyzer with the NOS ear parts but I do have a nice oscilloscope and sig gen.

:) This is the kind of discussion that makes sense to me. I may have went off a little bit in my earlier post but it's just the frustration of trying to sift through the info on the web to improve my tone and not spend my mortgage money driving up the prices of obsolete pedals being sold and re-sold on eBay.
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Re: Boss - DC-2 ( Dimension C )

Postby lohstah » 09 Mar 2009, 18:35

today i made a last effort to solve the noise issue:
i made a daughterboard with the entire lfo on it, ic7, c29/30/36/37, r33/34/35/37/59/60, and from that board, connected +7v, gnd and point 14 (one side of the depth pot) respectively, plus ran shielded wires from the daughterboard to both sides of the rate pot, to pin 3 of ic5 and pin 3 of ic6. of course, i cut the traces going back from the connection points of the lfo to where the lfo originally was situated, eliminated ic7, c36, r59 from the motherboard.
it got a little better, but is still not anywhere near the original noise(less)wise.
i am giving up now. :( this has cost me too much time and effort already, i could´ve built at least 10 other boxes in the time it took me trying to solve the issue. i boxed the critter up, encapsulating the whole lfo board in shielded foil.
i think it will still be useable for playing live, still got to test that out though. next rehearsal will tell.
maybe it is the implementation of the two pots instead of the switches ? i don´t know.

cheers,
lohstah
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Re: Boss - DC-2 ( Dimension C )

Postby jfromel » 12 Mar 2009, 00:59

The pots instead of the switches should not make any difference, I have made units both ways. I have DIY PCB's for this project if you are still up for the challenge.
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Re: Boss - DC-2 ( Dimension C )

Postby puppiesonacid » 12 Mar 2009, 02:39

jfromel wrote:The pots instead of the switches should not make any difference, I have made units both ways. I have DIY PCB's for this project if you are still up for the challenge.


what do the pots do?

also, over on the electro forum I remember you selling boards. I thought you said it was different from the dc-2 and was more like the rack version? still interested in a board though....and the mn3011's or 3101's whatever they were...
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Re: Boss - DC-2 ( Dimension C )

Postby jfromel » 12 Mar 2009, 04:00

puppiesonacid wrote:
jfromel wrote:The pots instead of the switches should not make any difference, I have made units both ways. I have DIY PCB's for this project if you are still up for the challenge.


what do the pots do?

also, over on the electro forum I remember you selling boards. I thought you said it was different from the dc-2 and was more like the rack version? still interested in a board though....and the mn3011's or 3101's whatever they were...


If you want a standard rate and depth instead of the presets you can just use pots for that. The version I did over at electro-music is a hot rodded version that has stereo in/out, expanded LFO, input buffer and CV control. I have made a couple of these into really large pedals and have bypassed the buffer and did not wire the CV control.
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Re: Boss - DC-2 ( Dimension C )

Postby lohstah » 12 Mar 2009, 13:04

Code: Select all
The pots instead of the switches should not make any difference, I have made units both ways. I have DIY PCB's for this project if you are still up for the challenge.

that would be nice, i´m up for the challenge. it bugs me that i have an enclosure ready that will not fit much other projects (cause it´s so big it could accommodate the topo dc-2). what dimensions is your board ? i´ll shoot you a pm.

cheers,
lohstah
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Re: Boss - DC-2 ( Dimension C )

Postby puppiesonacid » 12 Mar 2009, 13:22

If you want a standard rate and depth instead of the presets you can just use pots for that. The version I did over at electro-music is a hot rodded version that has stereo in/out, expanded LFO, input buffer and CV control. I have made a couple of these into really large pedals and have bypassed the buffer and did not wire the CV control.


oh ok, that sounds cool. Hey this may sound ignorant but what is a CV control ( controlled voltage?) and how would it be useful for a guitarist?

thanks,

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Re: Boss - DC-2 ( Dimension C )

Postby jfromel » 12 Mar 2009, 16:47

CV is control voltage and I just put it on there for the synth crowd, for a guitarist it is pretty useless. Th input buffer is realy only good for studio guys so I bypass that when wiring up one for guitar.
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