bobtavia on a power supply question...

[pinkjimiphoton]

hola mi amigos,

i built a bobtavia a while back, one of my first builds, and i absolutely love it...i did the mod to switch the octave out (with a second footswitch) and it works great...even tracks well
all the way up the high e string, i've heard folks have had a problem with it doing that...what i've found is lead dress and no cold solder seems to cure that.

but the problem is, i really wanna add it to my pedalboard to replace the fox tone machine cloned dano french toast or whatever on my board.

so i added a dc power jack...and it works, but it hums like a marshall with blown filter caps and a shorted rectifier. i mean bad.

i tried adding a 100mf @ 25 volts electrolytic across the jack in various configurations, but it didn't help...the best i could do was across the two positive leads (the barrel and switch, as it's negative tip i believe) which nuked a LITTLE of the hum...but nowhere near enough to make this usable with a power supply.

anybody got any ideas as to what my best course of action is on this thing? i really wanna use it on my board!! but don't wanna have to hassle with a battery...

thanks in advance!

[PRR]

What power supply you using?

[petemoore]

  IF the battery is an improvement over your AC conversion supply.
  You can do better.
 See GEO 'the Spyder' power supply for the lowdown on ripple-free, floating supply lines, elimination of ground loops.
  This gives a good understanding of what's what, but there are good workalikes available with a comparitive investment to what building a row of floating/regulated DC supply lines DIY would cost.
  Choose a regulator that is 2volts less than your supply [takes 2 'extra' volts for it to operate], ie probably start with a 12vdc supply then add a 7809 regulator to get rid of the ripple.
  That gets rid of the noticable ripple [hopefully], so ground loop might be the next big contributor to noise.
  Who said it first: Noise elimination is like peeling an onion, one layer at a time, add tears to each layer.
   I'd have to add: "If you know what you're doing, you can just about buy the whole 'noise onion' and just crush it [every layer in it] as a first order of business using the above info. Worked fine for me unless I found a rotten spot that needed cut out.

[pinkjimiphoton]

hi guys,

i haven't tried it on my board's power supply yet, but the board runs a one spot, which i swiped to try and power this one. i'm a newb ( i've built about 12 boxes so far total), this is the first one i've run into this kind of problem with, so i appreciate the help and insights. it's dead quiet with a battery, fwiw.

i'm realizing now that i could make it smaller and slightly less complex than the cheezy layout i did, i just went from that page of beavis's, but haven't actually tried to build it yet..
i figured on a small board it would be easier to try it than rebuilding the whole pedal.

i'll google up the geo "spyder", thanks for the tip!
since this was one of my very first builds, i'm sure there's some mistakes in lead dress and stuff...i know some of them are probably way too long, etc.

live and learn...thanks for the info!

[mantella]

hey, I'm wondering if you ever figured out this issue? I just replaced my battery with an adapter on my Bobtavia and had the same thing happens. Sounds beautiful with a 9V battery. But horrible with the 9V adapter. Tried different adapters and can't get it to work right.

[pinkjimiphoton]

sorry bro, never got around to it, ended up building the mayer octavia instead. that's my favorite... the bobtavia is cool, but i guess it needs batteries.