questions on the runoffgroove Thunderchief

Started by EmilDK, July 17, 2006, 11:30:13 AM

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EmilDK

Hello, forum. I am a new user, but have been reading new posts daily for a while. I am preparing to build the runoffgroove thunderchief including the original tonestack
http://runoffgroove.com/thunderchief.html
http://runoffgroove.com/tc-tone.png with tone stack

I have a few questions for those of you who have build it, and anyone else who may be able to answer:

1) can you recommend a replacement FET instead of the J201, which scarce and expensive (3 - 4$) in my homeland, Denmark, preferably similarly spec'd and with similar pin-out?

2) am I wrong in assuming that i am able to use the tone stack alone, by tapping in before the buffer and out before the fourth FET?

further questions may follow

Thank you for your time,

Emil from Denmark

MartyMart

MPF102 - same pinout not as much gain as J201
2N5457 - same pinout slightly more gain than MPF102, still less than J201

www.smallbearelec.com has all these Fets

aron's store above has bags of J201's also at reasonable price :D

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=120008394490&ssPageName=ADME:B:EOIBSA:UK:31
dpi4parts is a great ebay seller, has many fets/transistors and is cheap too ... I just got some J201's from him

Not sure what you mean by "using tone stack alone" ?

MM.
"Success is the ability to go from one failure to another with no loss of enthusiasm"
My Website www.martinlister.com

SuperGeo

you can use also a BF245 but I don't know where does it fits in MartyMart's classificatoin  :D

EmilDK

Thank you for your replies, MartyMart and SuperGeo. I will be looking for these FETs.
As for my second question; I was hoping to be able to bypass the effect, but leaving the tone stack active. Meaning using the eq portion of the effect, leaving the rest out. The plan behind this was to have a regular on/off switch, and an additional dirty/clean, which would turn off the effect but allowing me to eq the clean sound. Am I making sense?

ps. So nice to have a place to go with my questions, and having them answered so soon.

Emil from Denmark

MartyMart

I see, you might be able to do that with a small dpdt switch, wired to replace the "gain" pot with a small
fixed value resistor, say 100k or less if it still distorts !
That would just switch off the higher gain seting of the pot and switch on the fixed "clean" setting , then allowing
you to just use eq  ....  BUT there's no eq section on the thunderchief ... just "gain" and "vol"  ??

MM. :icon_eek:
"Success is the ability to go from one failure to another with no loss of enthusiasm"
My Website www.martinlister.com

EmilDK

That was a great suggestion, MartyMart, thank you. On the second of the schems i have linked to in the first post, a tone stack is included. That is the one I'll be using.

About the BF245... there is an A, a B and a C version, right? Which one is closest to the J201?

thanks

Emil from DK