Most authentic Boss SD-1?

[neiltheseal]

Hey. I'm thinking of building a Boss SD-1 and wanted to know what as the most authentic pcb out there. Ideally I'd like to make the most authentic version but I don't know enough about this circuit to decide which. Any help is appreciated.

I have looked at the UberDrive obviously, but this schematic seems quite a bit different to the Aion FX version and the PCBGM version.

I assume that some of the differences are transistor related as the PedalPCB uses the 2sc732 which seem hard to get. Aion and PCBGM use easier to access transistors but seem to have two before the op amp whereas the PedalPCB version only has 1. Why is this?

Another difference is the pedal pcb version has diodes between pins 2 and 1 of the op amp (soft clipping?) but the other two have the diodes going to ground (hard clipping?). Surely these sound quite different.

 

[Laundryroom David]

Hey. I'm thinking of building a Boss SD-1 and wanted to know what as the most authentic pcb out there. Ideally I'd like to make the most authentic version but I don't know enough about this circuit to decide which. Any help is appreciated.

I have looked at the UberDrive obviously, but this schematic seems quite a bit different to the Aion FX version and the PCBGM version.

I assume that some of the differences are transistor related as the PedalPCB uses the 2sc732 which seem hard to get. Aion and PCBGM use easier to access transistors but seem to have two before the op amp whereas the PedalPCB version only has 1. Why is this?

Another difference is the pedal pcb version has diodes between pins 2 and 1 of the op amp (soft clipping?) but the other two have the diodes going to ground (hard clipping?). Surely these sound quite different.

SD-1 and DS-1 are very different critters

 

[Nic]

Like @Laundryroom David said, the ppcb uberdrive is a SD-1 clone, the other two are DS-1

 

[Bucksears]

I've got an etchable PCB layout for an SD-1 that I created using the 1981 MIJ version's service notes.
I removed the switching section, and made it very compact: it's less than 2"W, and a little over 2"L.

It's not validated yet, though.

 

[Diynot]

Paging @Guardians of the analog

 

[Guardians of the analog]

Build the Uber drive. Use 4148 for the diodes and whatever modern, easy to get transistors you can find, just watch the pinout. There is no magic in the circuit or any parts. I use cheap 4558s for the opamps as well. No cork sniffing needed.

 

[Robert]

and whatever modern, easy to get transistors you can find, just watch the pinout.

2SC1815 is a direct fit.

 

[T-Go]

In case you are interested in doing any mods, here's an article from Brian Wampler on some good mods.

5 DIY Mods to Perfect Your Ibanez TS9 and Boss SD-1​

I did the gain/bass boost mods on my SD-1 and made them switchable. Also changed R5 from 33K to 10K to allow the Drive control to clean up better when fully counter-clockwise (R6 on the UberDrive).

 

[Bucksears]

In case you are interested in doing any mods, here's an article from Brian Wampler on some good mods.

5 DIY Mods to Perfect Your Ibanez TS9 and Boss SD-1​

I did the gain/bass boost mods on my SD-1 and made them switchable. Also changed R5 from 33K to 10K to allow the Drive control to clean up better when fully counter-clockwise (R6 on the UberDrive).

Another one (again, not yet verified) is the 'Hot' mode from the Ibanez TS7, switchable by a toggle.
It consists of:

• Adding a cap in parallel (don't recall where in the circuit) to reduce the value of said cap (assuming it's a bass cut)
• Replacing a cap & resistor in series with another cap & resistor of different values

On an SD-1, the cap on line 1 (above) is already a lower value than on a Tubescreamer, so you don't need that; just replace the cap/resistor pair in series. I liked the Hot mode on the TS7 more than the Normal side, and always thought that would be an interesting mod to use/tweak in other TS variants.

 

[Guardians of the analog]

I like the sd-1 in stock form. I use it as a lower gain boost as it was intended. If you want to turn it into something it's not then build the dunes, it's got higher gain, clipping options and all that jazz built in already. The Uber drive is perfect just the way it is.

 

[neiltheseal]

SD-1 and DS-1 are very different critters

Thanks. I feel a bit silly.

I don’t think I’m dyslexic but sometimes I’m not so sure.

 

[neiltheseal]

Like @Laundryroom David said, the ppcb uberdrive is a SD-1 clone, the other two are DS-1

Haha. Makes a lot more sense now why the schematics were so different!

 

[Laundryroom David]

Thanks. I feel a bit silly.

I don’t think I’m dyslexic but sometimes I’m not so sure.

Don’t feel silly! Happens to us all.

 

[Feral Feline]

I'm a bittle lit lysdexic.

 

[music6000]

I like the sd-1 in stock form. I use it as a lower gain boost as it was intended. If you want to turn it into something it's not then build the dunes, it's got higher gain, clipping options and all that jazz built in already. The Uber drive is perfect just the way it is.

It's called the UberDrive as it's there when you need it! :

 

[Fizz]

How would someone give the Uberdrive a bit more ballz? I like it but I'm used to the new ones that have way more drive (which I don't need) but also more volume and treble. I like to run my new SD-1 with the gain on 0 and the level and tone on 10. This makes my 2204 very clanky if you know what that means? I love it but can't do it with the Uberdrive. I can max everything on the Uber and it has less gain and not as much highs.

 

[music6000]

How would someone give the Uberdrive a bit more ballz? I like it but I'm used to the new ones that have way more drive (which I don't need) but also more volume and treble. I like to run my new SD-1 with the gain on 0 and the level and tone on 10. This makes my 2204 very clanky if you know what that means? I love it but can't do it with the Uberdrive. I can max everything on the Uber and it has less gain and not as much highs.

The Uberdrive is True Bypass so technically it suppose to sound better but not always!
The SD-1 is not so that may be the different result you are getting???
The other is Pot values vary a lot, did you measure across legs 1 & 3 to see what the actual resistance was?
I have measured Alpha B10K from 8.5 to 12K
Did you use a B20K or B25K for tone?
Have you tried just turning the Gain knob up a fraction, it maybe cutting/ killing the volume loss your getting???
One mod is to replace C6 - 10nF with a lower value that will increase highs, you could try 4n7???

 

[Fizz]

The Uberdrive is True Bypass so technically it suppose to sound better but not always!
The SD-1 is not so that may be the different result you are getting???
The other is Pot values vary a lot, did you measure across legs 1 & 3 to see what the actual resistance was?
I have measured Alpha B10K from 8.5 to 12K
Did you use a B20K or B25K for tone?
Have you tried just turning the Gain knob up a fraction, it maybe cutting/ killing the volume loss your getting???
One mod is to replace C6 - 10nF with a lower value that will increase highs, you could try 4n7???

I'll have to check those values as I don't remember them off hand... its been a while since I built this one. I bought two of these so I plan on breadboarding the next one and I'll try this mod you suggested as well as some different pots to see how they sound. I run my Uberdrive with everything on 10 and it doesn't have a lot of gain or highs compared to the newer model of the SD-1. I suppose I could have messed up some parts. I'll have to check if the second one sounds different when I build it stock on the breadboard first.

 

[music6000]

I'll have to check those values as I don't remember them off hand... its been a while since I built this one. I bought two of these so I plan on breadboarding the next one and I'll try this mod you suggested as well as some different pots to see how they sound. I run my Uberdrive with everything on 10 and it doesn't have a lot of gain or highs compared to the newer model of the SD-1. I suppose I could have messed up some parts. I'll have to check if the second one sounds different when I build it stock on the breadboard first.

Can you show a good Photo of your current build & we can check for Resistor & cap values.

 

[Fizz]

Can you show a good Photo of your current build & we can check for Resistor & cap values

I had to post this when I first built it because I got the input wires crossed. Is this a good enough pic?