Madbean Smoothie: Can It Be Modified To "Vibe"?

[whitebread47]

As I have perused the depths of the internet (here, FSB.com, etc.) I have found out that many 'boutique' vibe designs are basically tweaked phaser circuits.  I read somewhere that the Lovepedal Vibe was simply a modified Phase 45, which the Smoothie is also based on.

So I was wondering: Can I make my Smoothie build sound more vibey?  If so, what would be the key mechanisms of doing this?

[madbean]

The Univibe effect is created by four phase shifting stages, whereas the Phase45 is two stages. So, you won't get a true Univibe but you might be able to get something convincing. You need to set C4 and C5 on the Smoothie at a 10:1 ratio, according to the info here: http://www.lynx.bc.ca/~jc/phase45modded.gif

Switch C5 to 100n.

Haven't tried this...let us know how it works out!

[whitebread47]

Great, thanks for the link!  I used to have a Sweet Sound Mofaux Vibe that I really liked, so I'm hopng to get a somewhat similar effect.  I'll socket those caps and see what happens.  I'll report back!

[jimijam]

The Univibe effect is created by four phase shifting stages, whereas the Phase45 is two stages. So, you won't get a true Univibe but you might be able to get something convincing. You need to set C4 and C5 on the Smoothie at a 10:1 ratio, according to the info here: http://www.lynx.bc.ca/~jc/phase45modded.gif

Switch C5 to 100n.

Haven't tried this...let us know how it works out!

i've done this mod and it does have a convincing vibe tone.

[pryde]

Might be cool to put it on a switch for phase/vibe option?

[eldanko]

Might be cool to put it on a switch for phase/vibe option?

Bingo.

Hmm... think you can cram a switch into a 1590A as well...? 

[midwayfair]

Hmm... think you can cram a switch into a 1590A as well...? 

I think this has to be a dpdt switch -- you have to change two caps. Correct me if I'm wrong, because I have one of these on the work bench with a mix knob and can always use an excuse to add options or build a second! Tayda (I think that's where I got the one I'm looking at) has a submini that will fit. It's tiny. It's shorter than their SPSTs.

The main issue is -- what to do about the 500K reverse pot. Chances are most of us had a 16mm pot because that's the one Tayda and Smallbear have, and a DPDT will probably be too wide to fit next to it. But Smallbear does have a 9mm 500K reverse. You can easily fit the switch with one of those.

As for fitting a regular sized mini switch, it will just barely fit without touching the board with the inner nut removed. But I think it looks ugly on the outside like that ...

[whitebread47]

Hmm, I was actually planning on a 1590B for mine.  I'm mainly using a step bit, so drilling for the jacks is easier in the 'B' size (too cheap to buy more bits right now, heh).

I haven't exactly modified anything up to this point (about 12 builds deep), so I am curious how one would go about putting those caps on a switch.  I'm assuming I would need the other caps wired on a small piece of vero?

[Matt Gnarly]

I haven't exactly modified anything up to this point (about 12 builds deep), so I am curious how one would go about putting those caps on a switch.  I'm assuming I would need the other caps wired on a small piece of vero?

You don't necessarily need vero, you can leave it floating as long as it doesn't cause a short.

[midwayfair]

I haven't exactly modified anything up to this point (about 12 builds deep), so I am curious how one would go about putting those caps on a switch.  I'm assuming I would need the other caps wired on a small piece of vero?

You don't necessarily need vero, you can leave it floating as long as it doesn't cause a short.

Yes, but if it's two caps that need to be switched to two other caps, it simply can't be done with a SPST. Wire each side of the switch like the SPDT in Boxcar's post.

[whitebread47]

Awesome, thanks to both of you for the help!  I will have to wait until I get some matched JFETs in from GuitarPCB (it's worth saving my time for that and don't want to buy 100 2N5457s) before I can execute and report back, but rest assured that I will!

[madbean]

You don't need to switch two caps. You only need to switch one in parallel. An 82n or 100n in will work.

[whitebread47]

You don't need to switch two caps. You only need to switch one in parallel. An 82n or 100n in will work.

Ah, I got it now.  It's similar in principle to the input cap switch on the RangeMaster, just switching the cap value; a SPST should work.

I think I am about to start socketing and tweaking everything now, especially with all the diodes I got coming from midwayfair. 

[midwayfair]

You don't need to switch two caps. You only need to switch one in parallel. An 82n or 100n in will work.

That's good to know ... Philpot's mod schematic showed two, but maybe he was just showing both places it could be done.

[sgmezei]

Okay so I just add one cap in parallel with C4 or C5?

Just wrapping my head around this.