Revibe: speed pot 5.1m

[lego4040]

How everyone doing these days. I haven't had much time or money to build lately so I decided to revisit Sluckys Revibe and do some cleanup on the circuit. I noticed I don't have the 5.1M across the pot and can't remember why I didn't put it. Either I totally missed it or I left it out for more speed control?

[John]

That may have been his way of getting a 2'ish Meg pot?

[sluckey]

The smarty pants answer is "If you don't remember why you don't have that resistor, then you don't need it."   

We talked about this before. See reply 84 and 85 in this thread...

     http://el34world.com/Forum/index.php?topic=17195.msg174266#msg174266

The reason I used a 5.1M resistor is because when I added the fast/slow switch, my oscillator would die if you turned the speed pot to zero while in slow mode. Putting the 5.1M across the pot increased the slowest speed of the oscillator just enough to prevent the oscillator from dropping out a slow speed. Not all circuits will need this Band-Aid. I've since then built this exact same circuit but did not need the 5.1M.

The answer is also on my Revibe schematic.

[lego4040]

Thanks Steve, I knew it was in one of the threads. I finished cutting back excess wires and what not, ran outta time as usual so firing it up will wait till tomorrow. Next fix will be to remove the cascade from the AC -15

[Ed_Chambley]

The smarty pants answer is "If you don't remember why you don't have that resistor, then you don't need it."   

If this is true there are a lot of things I don't need anymore.

[lego4040]

Good one Ed. I'll be giving my Son his first amp next month, it's the Stout in a custom cab I have, just need to look at GWS and get a 12" speaker for it. I cut back almost 1' worth of extra wire floating around in the revibe, went over a few other joints and amp sounds quieter, I don't like the tremolo in it tho. Not after playing the AC-15 and 5G9-A builds I did. I just turn those pots to zero, can I bypass all that circuit now

[sluckey]

I'm surprised you don't like the harmonic vibrato (tremolo) in the Revibe.

Bypassing the entire vibrato circuit is not as simple as disconnecting this wire and putting another wire somewhere. But it would still be pretty simple. Refer to the revibe schematic. V1B needs to be converted to a simple fixed bias cathode follower. The output of that cathode follower would then connect to the bottom of the mix pot. Then connect the wiper of the mix pot directly to the output jack. Now you can remove V4, V5, and all associated components. The end results will be a 6G15 stand-alone Fender Reverb unit. You also need to refer to the 6G15 schematic to see how to wire the cathode follower.

[Willabe]

I don't like the tremolo in it tho. Not after playing the AC-15 and 5G9-A builds I did. I just turn those pots to zero, can I bypass all that circuit now.

Are you sure you want to do that?

That harmonic vibrato has it's own sound and has it's own place and uses.