Boss - DS-1 Distortion mods (what works, what doesn't?)

Aharon · Post by **Aharon** » 05 Sep 2007, 17:02

There seems to be DS-1 mods everywere but opinions are mixed,some people report great results while others say they buggered their pedal and they want it back to stock.
Any of you tone fiends have the definitive mods for the little orange box?
Thanks
Aharon

Post by **modman** » 05 Sep 2007, 21:35

Aharon wrote:There seems to be DS-1 mods everywere but opinions are mixed,some people report great results while others say they buggered their pedal and they want it back to stock.

I also have an orange fellow on the shelf. Bought it for 22EUR with a broken switch I think it was last summer. Don't have anything in particular to advice, but maybe look at the derivative boutique boxes?

Though I do want to try mosfets for clippers in a box sometime.

grolschie · Post by **grolschie** » 06 Sep 2007, 22:18

The Keeley mods sound great.

Post by **modman** » 22 Oct 2007, 12:46

I put in a new switch in my DS-1 yesterday. Now I'm looking at some pages with mods, but pretty sure I'm going to try a mosfet clipper, because everybody just using leds anyway. Not to say the leds don't sound better than the stock diodes.

http://www.robertkeeley.com/audio6l6/dstech.html
http://www.erikhansen.net/?page_id=28

If you google for this ds-1 boss mods brings up so many ebay listings and harmoney central reviews, you should add something like 'uF' to the search to get some REAL info.

Has anybody tried using different ICs, I wanted to ask, but instead I ask, how about that 7pin opamp?

Aharon · Post by **Aharon** » 22 Oct 2007, 14:19

Thanks for the input modman.
I built one with the tonepad layout using a 4558 and it sounded a lot fuller than the original just like that.
A nice thing would be to have the original schemtic so to see what corresponds to what on the tonepad schem and build the ultimate DS-1 from scratch,all the mods etc. although I don't think it would be difficult to sit down and figure them out either.

Aharon

Post by **modman** » 22 Oct 2007, 20:11

Hi Aharon,

Here another nice piece of info making it quite easy to figure out the keeley mods:

http://www.indyguitarist.com/mods_new/keeley-mods.pdf

The schematic and parts layout is even linked to on wikipedia:

http://www.godiksennet.com/images/sch/DS1PG2.jpg

thanks for the great pictures, Brian!
Going to try some of this tonight.

modman

Aharon · Post by **Aharon** » 22 Oct 2007, 20:34

Wow thanks.......my google skils are seriously lacking.Your kung foo is good.
Aharon

Post by **modman** » 22 Oct 2007, 22:25

Aharon wrote:Wow thanks.......my google skils are seriously lacking.Yor kung foo is good.
Aharon

still learning every day...

Already replaced most of the caps in the mod, but on the verge of replacing every capacitor on the board. I used wima 5%.

Never saw a 0,47uF polarized cap before, I must admit. Soldering iron is still hot, so cu later.

JHS · Post by **JHS** » 23 Oct 2007, 09:06

There are 2 basic versions of the DS-1.
Before you start you should discover which circuit is used in your box.

I know at least a dozend different mods for the DS-1, so get as much information about this topic as possible before you start modding your FX. Nearly all modders perform the same basic mods on the DS-1 circuit, so comparing the different mods first would be a good idea.

If you want to know what works and what not breadboard the basic circuit, do the different mods and listen to the sound.

IMHO a subtitution of the cheap caps is what you should do first.

JHS

bajaman · Post by **bajaman** » 23 Oct 2007, 09:24

IMHO a subtitution of the cheap caps is what you should do first.

Absolutely agree with this

Surprises me how many " top name " pedals use shitty cheap mylar film caps

bajaman

Post by **modman** » 23 Oct 2007, 14:08

Caps I removed from this 1986 DS-1:

,
Here the board with all the secret mods that some people know and other like me just read the first link I posted.

Solderside whilst performing the modifications:

Cleaned up and 're-knobbed': ready for ebay

How I initially bought, it, switchless, knobless and dirty:

I do notice a improvement in the sound rather than a real modificatin to the circuit. These mods really clear out the highs and give better dynamic response to playing.

Let's start a thread about Capacitor Quality?

Aharon · Post by **Aharon** » 24 Oct 2007, 17:42

JHS wrote:There are 2 basic versions of the DS-1.
Before you start you should discover which circuit is used in your box.

I know at least a dozend different mods for the DS-1, so get as much information about this topic as possible before you start modding your FX. Nearly all modders perform the same basic mods on the DS-1 circuit, so comparing the different mods first would be a good idea.

If you want to know what works and what not breadboard the basic circuit, do the different mods and listen to the sound.

IMHO a subtitution of the cheap caps is what you should do first.

JHS

Yeah,best course of action,build the tonepad from scratch again and do all the mods and see what works.
Aharon

Post by **modman** » 24 Oct 2007, 18:26

My experience with these mods, whoever invented them, that they don't change the nature of the circuits, but rather improvements in the rendition of the DS-1 of what it might be.

Will have a look at tonepad still, but could build it from the schematic if I wanted.

Again, what about the orignal Hitashi opamp's 7th leg?

Post by **modman** » 30 Oct 2007, 19:18

As prescribed by Keeley, I changed the first clipping diode to a red led. The second diode in his mods go to a switch that adds an extra red led in series with the second diode.

Wanted something original so I tried out using a mosfet clipper for the second diode: check Jack's article here http://www.muzique.com/lab/zenmos.htm

I used this configuration:

Not turning back now, it sounds interesting to say the least. The original sound sounded so familiar although I never tried this box before. If you want that real 80s flat response distortion, don't mod your DS-1

Post by **modman** » 01 Nov 2007, 23:09

DS-1 Part layout and values from a great japanese diy blog, to complete the DS-1 file. The other layout is kind of scruffy, though this might be an younger version? Haven't compared them yet.

bajaman · Post by **bajaman** » 02 Nov 2007, 01:43

though this might be an younger version? Haven't compared them yet.

Yes - this is the original 1980 DS-1 layout. The more recent one has the dc socket mounted on the board, uses the smaller green pots and an TL072 IC instead of the original Hitachi 7136 chip. I have yet to see the layout for this newer version posted anywhere - all the schematics I have seen and have are for the earlier version, and do not contain R39 or R40.
Cheers
bajaman

ps: a mod I like to do, is replace the input buffer transistor with an n channel jfet, such as a 2SK117 - much less tone sucking and more clarity on bypass

Post by **modman** » 02 Nov 2007, 10:46

Baja,

Where do you get your sk117s? Seems to be very scarce and expensive. I mean > $1 . I did find what I think is a K117 on the board somewhere else, will have to check later. Now off to the doctor with an eye infection - new interpretation to the

icon

I checked mine in the boss serial decoder and it said May 1986.

http://www.bossarea.com/serial/sndecoder.aspx

This was added in the links section too

bajaman · Post by **bajaman** » 02 Nov 2007, 11:28

Where do you get your sk117s

I get mine from a local television wholesale warehouse - and yes they are not cheap devices here too.

bajaman

Post by **modman** » 03 Nov 2007, 21:56

Would another, more common, jfet alternative improve matters? I have about anything except that darned (2)sk117 you got me breaking my head over: (2s)k170, j-series, 2n54**

bajaman · Post by **bajaman** » 03 Nov 2007, 22:22

yes - almost any n channel jfet will work fine as a buffer - try an MPF102, 2N3819, 2N5457,58,59 or even a J201 - they will all improve the input impedance of this pedal.
cheers
bajaman