I have SD Invader in the bridge of my Epiphone. That's the only one pick up in my guitar, and I have one 500k volume pot. I instaled the pick up from the diagram which I found on the SD web site.
Here is the problem: recently I bought DS1 and when I pluged it in my guitar and in the JCM800 100w + 4X12 level of the signal went down. On my MT2 that' not the case. I tried others DS1 in the store and there is the same situation with the weak signal. On some cheap guitars in the store level is going up.
Has someone had same problem, I found some video clips where is the same problem with DS1. Can somene help me, I'm going crazy!

DS-1 is pretty shitty. I have a DS-1, and an invader knockoff. If you are just wanting to use the DS-1 for a gain boost, get a bad monkey from Digitech, kinda like a cheap TS-9. But I've never heard of the problem, I could dig through my closet and find my DS-1 and try it myself. If you never resolve the problem just get a Bad Monkey, only like 40 bucks.

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Uh, is your level knob on that pedal working? Could be that the level knob/pot is faulty or there is a faulty connection in the pedal making the signal drop.

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No, the pot on the DS1 is working fine. The DS1 is brand new, I even tryed couple of other DS1's in the shop and they all have the same effect.

Don't use distortion pedals for boost.
Get a overdrive, like a tubescreamer or bad monker or something simmilar,
or maybe use a EQ pedal for clean boost.

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Maybe take it back and swap it for the SD-1 which is a much more popular choice for boosting and is a Fav for a lot of JCM800 users. Just check the Marshall forum for proof, those guys love that thing. Either that or I can vouch for the Bad Monkey, awesome no-nonsense pedal.

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