Ruby Overdrive?

[ezanker]

Hi All,
I have breadboarded the ROG Ruby amp (http://www.runoffgroove.com/ruby.html)  using Small Bear's JRC chip and MPF102 for the buffer.  I am testing it with a 9V battery into an 8Ohm 4x10 Bass Guitar cab (Gallien-Krueger).

The amp sounds fine, however it is clean at any settings of the 2 pots.  Reading the description and other posts here, I would've expected some breakup at high drive settings.

Any ideas as to what I may have gotten wrong?

Thanks,
Erik

[RDV]

Are pins 1 & 8 tied together?

RDV

[Peter Snowberg]

Try disconnecting the wiper of the volume pot and connecting that to the signal input. Turn your guitar volume to full and hit a chord. You should get plenty of distortion. If you don't, check your output capacitor and the .047uF cap in the conjunctive filter on the output.

Maybe your JFET is an especially low gain one?

[Steben]

I'm getting tired of sying this  :? ........

Use a fetzer valve instead of a buffer....
with 1 and 8 of the chip disconnected.

[B Tremblay]

Erik,

I also used an MPF102 and JRC386 from Small Bear when building the Ruby prototype.  Mine begins to break up when the Volume is past 2:00 and the Gain is past 12:00.

Are you certain that the Gain pot is wired correctly?

Try this:  Set the volume at 12:00.  Set the Gain at minimum, then turn it up while playing.  Does the Gain pot affect the output level when increased?

If it doesn't, then check the Gain pot wiring.

Does your instrument have relatively low output pickups?  Is the instrument volume at maximum?

[ezanker]

Thanks for the responses!

Are pins 1 & 8 tied together?

I have tried both the gain pot and the set resistor mod for the Bassman sound.

Try disconnecting the wiper of the volume pot and connecting that to the signal input. Turn your guitar volume to full and hit a chord. You should get plenty of distortion. If you don't, check your output capacitor and the .047uF cap in the conjunctive filter on the output.

Will give it a try after work tonight. Thanks for the suggestion.

I'm getting tired of sying this Confused ........

Use a fetzer valve instead of a buffer....
with 1 and 8 of the chip disconnected.

I'll give that a try too... :idea:

Are you certain that the Gain pot is wired correctly?
Does your instrument have relatively low output pickups? Is the instrument volume at maximum?

I've tried a set resistance as well as the gain pot and I'm pretty sure the pot is wired correctly.  My instrument is a single coil '57 reissue strat, so the output could be relatively low.  Vol was at maximum.  I'll try my humbucker guitar tonight.

Again, thanks for all the ideas, I'll let you know what happens...

Erik