Thunderchief build report....actually OK!!!!

[Lucas Grijande]

Hi, i'd build this today but,again, i have a problem/problems....I don't have the j201 so i put BF245b on this,the problem seems to be in the last fet (fourth) the other ones are ok , but i don't have voltage in the last one :cry:  i'd cheked the circuit against the eschematic but i can't find the problem....can anyone help me? (one more time)

Thanks

[RDV]

You must have the 100k trim wired incorrectly.

Regards

RDV

[Lucas Grijande]

I have news:

I'd changed the 22n cap that goes to the gate of the last fet....now it is 4.5 at drain,1.5 at source and 0.0/0.1 at gate but no sound is being produced only a minimal signal...when i make a "bridge" with the 1,2 and 3erd fets and the output the signal goes up...a lot!!!

[Lucas Grijande]

It's working!!!  But not fine at all.....   The gain is not very high...less than a "normal" overdrive.
I'm not sure if the BF245B's are the problem...Maybe,when i put on a couple of J201,i'll get more gain?

[smoguzbenjamin]

Perhaps. Whenever you don't use the parts mentioned in the schem, you're going to get different results. Remember that every time you sub a part.

[Lucas Grijande]

Je,je,je i had make a conection between the 22n cap in the Q4 gate and the trimmer on his drain!!!!! and there is not a conection.... :oops:
Sorry.....
Now my Thunderchief is very good sounding , he has a lot of gain and he sound more like a cranked marshalll now...very good dinamics and good harmonics too....maybe a bit noisy... but now, i can play with him and i dont must wait to receive the j201's from smallbear to get fun of him!!!

Thanks all the people and Runoffgroove guys for this and the many other projects that you share with us!!!! THANKS :wink:

[Lucas Grijande]

I don't know how implement the superlead tone stack and the asociated buffer on this...Any idea? I know it must be between Q2 and Q3 but i can not figure how it must be to goes properly...What values? Where i must connect it? ...

[Lucas Grijande]

I have another idea:  I already have in a small piece of perfboard a "discrete buffer" from GGG
http://www.generalguitargadgets.com/v2/diagrams/buffer_jfet_sc.gif
Can i put this between Q2 and Q3? After playing a few hours with it i've noticed that with my danelectro surf & turf (compresor) between the guitar and the thunderchief all the noise goes out...in bypass mode too! So i wish put the discrete buffer on this but i'm not sure how can i make it...

[javacody]

I think you'd want to buffer the input of the pedal, that way the noise isn't amplified by the first JFET stage.

[Lucas Grijande]

Thanks Javacody!! but how can i connect the tone stack?