Boss - SD-1 Timmy, Landgraff, CJOD, BBOD, BMOD

[modman]

I apologize for my mistake. No offense meant. I represented the mod, I haven't said I invented it. If it was to be a touchy subject, I wanted to be the one to take the blame.

Apologies don't help me when I get a letter saying "this is a protected drawing, take it off-line or legal steps will be taken". The drawing must be taken offline. Same here, in the strict sense, you are voilating copyright by taking Analogguru's text and representing it as your own. It should be marked in some way and the source mentioned.

Aye, there's the rub - freestompboxes.org is censored by those lovely guys and you cannot post a link over here. Let's just assume they don't want to know and let them be. They should come here if they want the cookies.
No harm, but it is just a matter of courtesy in the end.

[Rocket Roll]

...you are voilating copyright by taking Analogguru's text and representing it as your own.

I've corrected it (which is to say, I've written that I only represented the mod that Analogguru came up with, both here and on DIYStompboxes). If there's something else I should do, please tell me which further steps should I take.

This representation of the CJOD mod didn't come out the way I meant it to, and I'm really sorry because of that.

[analogguru]

Yeah, it´´s ok.... let´s finish with this matter.

You don´t have to have fear to be blamed - if there would be something in my mod-suggestions where someone could be blamed for, i simply wouldn´t post it.,

BTW: Do you like that mod personally ?

analogguru

[floris]

Here is an actual link to the schematic I had drawn:
http://homepage.ntu.edu.tw/~r95625018/SD1.jpg

This link seems to be dead: 404 Not Found

[Rocket Roll]

Thanks for kind words and for your understanding, Analogguru.

And thanks for the great mod. I'm off to test it on a Marshall JCM800 and with humbuckers, and I expect it to perform impressively in that setup.

First, the difference between a stock SD-1 and this mod is (IMHO) a large one. I've never heard a stock SD-1 before this one came to me, and I didn't quite like it - "unflexible" sound, that's how I've heard it. Pretty harsh. OK as a tube amp booster ("Drive" at minimum, "Level" cranked) and that's about it.

Enter this mod. As I prefer red LED diodes in the clipping stage, I find that this configuration brings out "the good" in them, in an almost exemplary manner. There's that "nice fuzz" in the bass part of the tonal spectrum, there's that dynamic in the sound (play soft and they will be almost imperceptible, hit the strings hard and they will start to "cut"). Compared to my Turbo Rat, there's more mids, in a good way (just about enough, any more and the pedal would sound less transparent). Overall, the sound seems much "softer" and "bigger", it "flexes" more, and "the color" of the note changes as it drops. Now the pedal "thickens" the singlecoils nicely and takes you to the "Marshall JMP Rock God" land with "Drive" cranked.

I wish I had the time to "clean" the power filtering a bit - I find this pedal, as well as a lot of Boss pedals, "on the noisy side" when compared to any DIY booster/overdrive which has, say, a couple of strategically placed tantalums and metal-film resistors - so I'll have to see how prominent would that amount of "Boss hiss" be in an live setting. If I have to guess, I'd say it'll be manageable, especially with humbuckers.

Overall, a nice, just-about-enough-sharp, thick rock drive which is "on the civilized side" (ie. not too much distorted), and a very "ear-pleasing" one in that context. Like a bodybuilder with a tie. Bruce Wayne of the pedal world.

Yeah, as soon as I've seen the mod (developed by Analogguru, with red LEDs and so on) I knew it'll be at least a good sounding one, and it turned out in a "I can see why someone would pay $1000 for that sound, if he wanted an ear-pleasing rock drive".

[ChristoMephisto]

Don´t forget to change the tone-control. Since I don´t have the time to draw that up, here are the steps for the (non-mojo) basic Jones-mod:

1.) Remove R5 - R9, C2 - C6, D4 - D6, IC 1
2.) place a jumper wire instead of D5
3.) assemble a socket for IC1
4.) assemble R5 = 10k, R6 = 1k, R7 = 1k, R8 = 220 Ohm, R9 = 1k
5.) assemble C2 = 100n, C3 = 220n, C4 = 220n, C5 = 220n, C6 stays empty
6.) solder a 10k resistor in parallel to C4
7.) assemble the 2 red 5mm LED´s in D4 and D6
8.) take a chip of your choice (OPA2134) and plug it into the socket.

Now you have a (non-mojo) Jones-SD-1 and saved more than $1.450,--...

analogguru

Whats going on with the 10k parallel to C4?
Mids boost? part of the Tone control

[plexilover]

hi,
anyone who got infos bout the gt mod from monte allums, i know its working with a opa2134 and a 2N3440 but about the other things, resistors tantalum caps?
anyone?

greets
plexilover

[modman]

hi,
anyone who got infos bout the gt mod from monte allums, i know its working with a opa2134 and a 2N3440 but about the other things, resistors tantalum caps?
anyone?

greets
plexilover

PURCHASE MOD INSTRUCTIONS
WITHOUT PARTS
FOR $9.99

Dig da mouse! Maybe your so blown away by the sound of the Super Reverb that you didn't see the information below:
http://www.monteallums.com/mp3s/SD1_GT.mp3

What's that snapping footswitch, btw?

With this Kit you will receive a 3mm Super Bright White LED, two Tantalum Capacitors, two Metal Film Capacitors, one Carbon Film Resistor, three Carbon Composition resistors, one 1N4002 Diode, one 2N3440 Transistor, Burr Brown OPA2134PA Opamp with socket, Two Switches, 24 Ga. Wire, Heat Shrink Tubing, Solder and Desoldering Braid along with detailed easy-to-follow Mod Instructions.

Better read the FSB mods and save up for a Super Reverb.

[BJF]

Hi,

Well, no manufacturer of LED's define the knee, at best forward voltage appears as a blur at the beginning of the curve, which just happens to be the region of interest in this application. It would typically suffice to state typical turn on voltage as current through the LED is far more important for LED brightness and so LED manufacturers might state a current versus brightness graph, and voltage is just assumed to be nominal.
There was in the late 70's early 80's a popular thing to use e.g red LED's as voltage reference in poweramplifiers and the a red LED was assumed to have a turn on voltage of 1V7.............
However I asked my local submarine engineer to draw a graph of dynamic resistans range of 300 pieces of 3mm red LED's from the same manufacturer and the graph looked similar to the input caracterics graph of a triode. About 30 pieces could be matched outof the 300 units tested. Different makes of 3mm red LED*s can be had with a turn on voltage ranging from 1V5 to 2V0....Low current types will show a more gradual turn on than higher current types. In the application the LED's would be used as dynamic resistanses and that parallelled with a resistor, the value of which also will have an effect. There is further a parallell capacitance over the LED's and neither that is defined from any manufacturer......It is possible to match one 5mm LED with one 3mm LED if they are of the same type, which could falsy lead to that there is no difference between what type of red LED is used in this particurlar application..........truer would be that the more interesting for the application it would be to have consistency, the more LED's should be viewed as individuals.
From a sound and dynamic behaviour point of view as would be interesting to a musician or as how audiable the difference of the exact type of red LED's used would be may also depend on wether you just strike down hard or employ dynamics of playing........

Now as for other colours of LED's, things would be similar but different. There was a time when yellow and green LED's where considered equal in typical use as in forward voltage approximately 2V0 - but actual range is more like 1V8 to 2V2, and this is not a typical use, so agian LED's used would be best viewed as individuals, while it is possible to match one yellow LED to one green LED...............


http://www.youtube.com/watch?v=Q7oUwPIWCYI

Gentlemen have fun
BJ

[floris]

Warning, large photo's post... sorry about that...

Whats going on with the 10k parallel to C4? Mids boost? part of the Tone control

I did a simulation of the:
- Stock tone
- CJOD tone
- CJOD minus 10k tone

Schematics I used:
- Stock tone


- CJOD tone


- CJOD minus 10k tone


Frequency plot:
- Stock tone


- CJOD tone


- CJOD minus 10k tone

[ChristoMephisto]

Took a bit, but i think i get it...
with the 10k, it drops it a db but keeps the highs at the 720Hz, giving it a boost at the hertz
without the 10k, the highs gradually build up to 720Hz and less noticable at that hertz as a passive low cut
Those graphs are amazing, thx!!!

just a thought, if you left the first resistor a 10k would the other resistor be a 100k that's parallel to the cap?

[floris]

Imo the 10k resistor doesn't seem change/add much, can't really see the point of it.

[BJF]

Hi,

Well, for the tone amplifier, in SD-1 the bias is obtained via R4 and therefore strictly does not need the bias return of R6. If the toneamplifier would be AC coupled then it would need R6, and if so R6 would be choosen to be at least ten times the value of R4 for minimum loading, just a rule of thumb with voltage transfer: this would result in 10% loss, which would be considered acceptable. If one also consider the source impedance as seen at the noninverting input it would be even lower due to C3 so for the filter action influence of R6 can be considered neglible, something that would be evident from the schematic.

In my opinion R6 at the choosen value is a component you can have or not have as in let's proceed on what looks good

However

Rule of japanese design: remove one part at a time until circuit ceases to work and put back the last part.....

Perhaps of interest considering the topic
viewtopic.php?f=7&t=953

Have fun
BJ

[floris]

BJ, thanks for that interesting info.

[Greenmachine]

Analogguru, thanks for this post. The mod is kick-ass. The SD-1 sounds much better.

[pissdrunx]

I found some link on the web that shows how to turn your an sd-1 to something similar to lovepedal eternity. Has anyone tried this before?

heres the link if you are interested:
http://www.indyguitarist.com/news-lovepedal1.htm

[nooneknows]

I modified today my sd-1 along Analogguru rules .
I also changed:
C1 and C8 = 100nF polyester
C7 and C10 = 1uF polyester

No jokes, it sounds great!!

Thank you
M

[BAMF]

Might as well share my notes. This is borne from a 1:1 comparison of the Boss SD1 and the Lovepedal Eternity. I'll follow up with a component map for the Denio SD10 too.

Format is <part no>- <original value>-<mod value>- <action>


D3 - 1n4001- remove and jumper (it's said removing this makes the pedal sound fuller)
D4 - 1n4148 - 1n4148+1N4148 in series (makes clipping smoother)
D6 1N4148 - 1N4148 (makes clipping smoother)

R6 - 4.7k - 3.3K (higher bass cutoff, but balanced out by C3, increases gain)
R7 - 10k - 1k (decreases sag, punchier sound)
C2 - .018 uF - ,047 uF (metal film) - (fuller sound, removes the nipis)
C3- .047 uF - 0.1 uF (more bass, in conjunction with R6, increases gain)
C4- -.018 uF - 0.15 uF (treble cut, darker sound)
C6- .01 -remove don't jumper (removes a filter on the 2nd opamp stage)


R3, R15 - 10k - 10k metal film (hi-fi, but optional)
R5- 33k- 20k (this is just for authenticity along with VR1. you can leave it out also. lowers gain of ped.)
R9 - 10K - 1K (lowers gain on the 2nd stage, if you don't like it, put the original back)
R16 - 1k - 1k metal film (more hi-fi sound)
R31- 470 ohms - remove and jumper (removes power supply sag; normally already jumpered in newer SD1's)
VR1 (gain) - 1M - 500k (this is just for authencity, you can leave it out if you want but together with R5.lowers gain of ped.)

* add a 47p capacitor across the D4 combination
*change the IC to something better like an RC4558 or RC1458. Since the original eternity does not have an input buffer I'd recommend using a TLC2262 or TL072 or LF353 in there.

[BAMF]

Follow up.

Here are my notes to convert a Boss SD2 pedal to Lovepedal Eternity.

Boss SD2 to Lovepedal Eternity
R20-2.2k - remove and jumper
R32- 560 ohms-10k
R37- 680- 3.3k
R36-10k-30k
R46- 4.7k-10k (metal film preferred)
R49-22k-remove don't jumper
C32 - .022-.22
C12-.022-.047
C16- 22pF- 47pF
C24-.039-.15
C28-4.7uF- .1uF
C36- remove and jumper
C47-.0027- remove don't jumper

[roseblood11]

Well, converting a Boss pedal takes more time than building an Eternity from scratch...

And the most important differences between the Eternity and the Boss SD-1 are

a) the tone control
b) the fact that the Eternity doesn´t have input and output buffers.

There are different versions of the Eternity, both with symmetrical and asymmetrical clipping.