Anyone tried modding an SD-1 for symmetrical clipping?

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Rex Rocker

Rex Rocker

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I love the TS808. I just think the SD-1's steeper low-end rolloff gets along better with certain amps like Rectos. I do, however, feel the voicing gets a little edgy and not as smooth even when you set the tone knob to (loosely) match the brightness on a Tube Screamer.

I know the SD-1 is close to a Tube Screamer circuit-wise, but I know it's not the exact tsame. The asymmetrical clipping is part of the voicing difference, but I know there are a couple other values changed throughout the circuit.

I wonder if removing (or jumping? Not sure what's the right thing to do here) one of the diodes would smooth it out just a tiny tiny bit while still maintaining the tightness from the more pronounced low-end rolloff. I mean, I don't want to turn it into a Tube Screamer. I already have a Tube Screamer. I just want to tweak it just a tiny tiny bit.

Opinions? Experiences?
 
Rex Rocker said:
I love the TS808. I just think the SD-1's steeper low-end rolloff gets along better with certain amps like Rectos. I do, however, feel the voicing gets a little edgy and not as smooth even when you set the tone knob to (loosely) match the brightness on a Tube Screamer.

I know the SD-1 is close to a Tube Screamer circuit-wise, but I know it's not the exact tsame. The asymmetrical clipping is part of the voicing difference, but I know there are a couple other values changed throughout the circuit.

I wonder if removing (or jumping? Not sure what's the right thing to do here) one of the diodes would smooth it out just a tiny tiny bit while still maintaining the tightness from the more pronounced low-end rolloff. I mean, I don't want to turn it into a Tube Screamer. I already have a Tube Screamer. I just want to tweak it just a tiny tiny bit.

Opinions? Experiences?
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what SD-1 are you looking to mod ???

if it's a newer one .... they are SMD parts .... and unless you have a Hot Air station ..... that will be tough ...

if it's a older one with through hole components .... you can mod it pretty easily to switch the clipping ...

pretty sure you can just lift one leg of one of the diodes ...... but it has to be the right one
 
griff10672 said:
what SD-1 are you looking to mod ???

if it's a newer one .... they are SMD parts .... and unless you have a Hot Air station ..... that will be tough ...

if it's a older one with through hole components .... you can mod it pretty easily to switch the clipping ...

pretty sure you can just lift one leg of one of the diodes ...... but it has to be the right one
Click to expand...
I'm not sure? I bought it new some time ago, though. Around the same time I got my TS808, so it must be from the mid-late 2010's. I don't have it with me right now, so no way of checking until probably the weekend. But if it's one of the ones that can't be modded, no biggie. I can just hunt another one down and keep this one as is. It does sound great. I'm just curious as to how it would sound clipping symmetrically.
 
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If you use a DPDT switch, you could potentially remove one of the diodes from the SD-1 PCB, wire those 2 empty holes to the middle 2 poles of the DPDT switch and on each side you could put a different (or no) diode.
That way you could toggle between 2 modes. Don't do this with a Made in Japan SD-1, as it has vintage collector's value, but a bog standard Taiwanese from the 90's or later, go for it!

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Anologman did the toggle mod to my '83 SD-1 and its become my main drive.
But I didn't try to do the mod myself.

Whether you attempt yourself or have someone do it, IMO its worth doing.
 
dcburn said:
Anologman did the toggle mod to my '83 SD-1 and its become my main drive.
But I didn't try to do the mod myself.

Whether you attempt yourself or have someone do it, IMO its worth doing.
Click to expand...
Just for asymmetrical/symmetrical? Or did he swap other components out?

How does it sound with symmetrical clipping vs. asymmetrical?
 
Rex Rocker said:
Just for asymmetrical/symmetrical? Or did he swap other components out?

How does it sound with symmetrical clipping vs. asymmetrical?
Click to expand...
If you want a true bypass version with upgraded parts .... I can mod one of my boards to make it switchable ....and build you one
 
Rex Rocker said:
Just for asymmetrical/symmetrical? Or did he swap other components out?

How does it sound with symmetrical clipping vs. asymmetrical?
Click to expand...
Honestly I like the 808 symmetrical clipping myself.
He also did the silver and FROG mods...

EDIT: Griff will take care of you!
 
It's not that big of a difference. You are probably hearing the deeper bass cut, and higher mid frequency peak.
 
i did the mod but on a od1(byoc) and did like it, sounds a bit fatter
 
yes, this is one of my favorite sd-1 mods. the tone focuses in on the lower mids. awesome mod!! i just jumper d6. you can get an alligator clip cable and hear it both ways realy ez to see if you like it
 
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