New at runoffgroove.com: Thunderchief

[will]

Hi Gary and Brian,

Your Thunderchief looks real good!

I would love to hear the sound clip but I can’t find it on your sound page. http://www.runoffgroove.com/salvo.html#thunderchief

A general question:
Have you tried doing a similar circuit using mosfets instead of the JFETs and limiting the gain to approx 100 like the 12AX7, by adding some resistance to the .68uF source cap? I wonder how close they might sound.  

I wonder if part of the secret to the sound is the maxed presence control.

Regards,
Will

[Gary]

Will,

The maxed presence control does make a difference.

[javacody]

Gary, any plans to introduce a perf layout for this baby?

[Doug H]

Thanks, all.

Doug, do you remember me asking about the SLO after you released the Meteor?  

Yes. I remember that. This CS JFET approach can be applied to a lot of different circuits.

BTW, everyone reading this that has not tried Doug's Meteor, do it now!  You've never heard a distortion pedal sound so good.

Thanks.  I have been using the meteor in my weekly gig and am very happy with it. It has exceeded my initial expectations by far, when in a live situation at stage volume. Makes my SS amp sound like a boutique...

Doug

[B Tremblay]

Gary, any plans to introduce a perf layout for this baby?

I plan to draw one today, actually!

[Arno van der Heijden]

Try using different JFETs. J201s provide more gain than the actual amp had. It sounds great, but may be too hot for some. Try lower powered JFETs for a milder, more classic sound.

Any suggestions for this?
What parameter should I be looking at in a datasheet? How much gain does a 12ax7 have?

[javacody]

Awesome Brian! I don't know what I'd do without Runoff Groove. You guys keep me busy!

I would really like to know, once I have the thunderchief done, how to do something similar for the famous 60's Marshalls.

[B Tremblay]

A (currently untested) perfboard layout has been added to the Thunderchief page: http://runoffgroove.com/thunderchief.html

[BILLYL]

As others have said - Runoff Grove keeps me busy.

Listen to the clip last night and the 14yo said - "Now that's the sound I'm looking for!"

I drew up a  EXPRESS PC layout.  Would like to have someone verify - please email if interested.


Thanks again-

BILL

[javacody]

What would 680nF be in uF?

[B Tremblay]

What would 680nF be in uF?

That would be .68uF

0.1uF = 100nF
0.01uF = 10nF
0.001uF = 1nF = 1000pF

We've decided to adopt the Euro notation style for new content at the 'Groove.  It reduces the confusion (though not in this case!) and gets rid of the pesky zeros when labeling the layouts.

[Jered]

Javacody,  that would be .68uF Arno, try 2N3819, 2N5457, 2SK30, or for more gain 2SK117, 2SK118, and 2SK184. MPF 102 fets will work but your not going to get the gain this pedal wants to sound really good.
 Good luck,  Jered

[Gary]

Arno,  check this out from the DIY FAQ:

"What FETs can I substitute in the Mini-Booster and Shaka etc...? I can't find the J201....

From Jack Orman:

This is a recurring question eventhough the information was in the Mini-Booster article at AMZ From the article: "The NTE458 usually has more gain than the J201, and the 2N3686 can provide gain of 500. The 2N5457, MPF102, and 2N3819 will produce less gain. Other substitute transistors include 2N5484, 2SK43, 2SK68, 2SK117, 2SK118, 2SK121, 2SK163 and BF245."

Java,
This circuit is based on the '70 Super Lead schematic on www.schematicheaven.com  The older amps are not very different.  It should be easy to change things around and have a JTM45.

[javacody]

Thanks guys,
I figured I just divide nF by 1000 to get uF, here is a parts list I threw together:

Resistors:
68K
2 - 1M
2K7
470K
2 - 1K
2 - 4K7
470
220K
2 - 15K
100K

Capacitors:
2 - 0.68uF  (680n)
3 - 0.0022uF (2.2n)
3 - 0.022uF (22n)
470p
2 - 0.1uF (100n)
100uF

Pots:
4 100k (trim)
1M Audio
100K Audio

JFET's:
4 J201's

Jacks:
1 Stereo
1 Mono

Switches:
1 DPDT or 3PDT

Does that look right to everyone?

[B Tremblay]

Does that look right to everyone?

Looks like you got them all!

[puretube]

:!:

[javacody]

Would a 500K gain pot, effectively lower gain on this effect?

[petemoore]

...try a 1 meg resistor, connected to lug 1 & lug3 of the 1M Pot
 Adjust as necessary

[bwanasonic]

Come to think of it- how come Marshall never did this themselves? Seems they went mostly the diode clipping route with their stompboxes, didn't they?

Kerry M

[Alex]

Come to think of it- how come Marshall never did this themselves? Seems they went mostly the diode clipping route with their stompboxes, didn't they?

Kerry M

...and with their amps too