Reducing gain in Sorcerer

[iamjackslackof]

Hey all,

Got a Sorcerer built, and its quite gainy. More than I like, and more than I expected for a Tony Iommi pedal. I swapped the transistor to a leaky 8 (yes 8...) hFE Ge transistor, and that helped some. But I'd like to get it closer to classic rock heavy and not 80s metal and beyond heavy.
I also swapped in 5 2N5484s for the current J201s, and little to no change in gain. Also tried just removing a JFET altogether, just stops working lol.

Any ideas? I was hoping I could do it with transistor swaps and no desoldering, but maybe not. I'm not sure if a couple resistors changes might do it?

Thanks!

 

[Chuck D. Bones]

Did you listen to any demos?

The following ideas are based on circuit analysis. I have not breadboarded or simulated this circuit. But it is very similar to circuits I have built.

First, check the bias on Q1-C. Should be up around 6V to 7V. Use a decent tranny for Q1. If you have an AC127 or MP38A, try those. Lower HFE does not mean lower gain, but it will mess up the bias and increase the pickup loading.

Try increasing R8 to 10K or 22K. See if that lowers the gain enough. If not, try increasing R13.

You can also try swapping R11 & R12 and reducing C8 to 470pF.

If none of that gets you there, then we can try bypassing the 3rd stage (Q4 & Q5).

 

[iamjackslackof]

Thanks @Chuck D. Bones . I am using an AC127 VII. not sure what the VII means, maybe the gain bucket?


I did listen to some demos a few months back when I decided to buy the Sorcerer, I forget what I thought, but I assume I liked it enough. Maybe it is higher gain than I expected. Either way, this is a good chance for me to do some mods, which I've not gotten to do many of. Thanks for the suggestions, I'll try some out and report back.

 

[Chuck D. Bones]

If your AC127 has HFE = 8 then eithere there is something wrong with your HFE measurement or that transistor is trash. Where did you get it?

 

[iamjackslackof]

I forget to be honest, maybe ebay? I'm using a DCA75, so it's probably the transistor. The whole batch reads super low like that or 250+ hFE, most with pretty high leakage.

 

[Chuck D. Bones]

I have not seen any AC127s with HFE over 150, most of the ones I've tested are in the range of 70 to 100.