replacing a TDK with a whipple on a 70's thomas organ crybaby

[MovingInSloMo]

ok cross post with madbean, but maybe different audiences..

This is going to prove to be an interesting process. Has anyone attempted this?

some issues.

1.) Firstly are the whipple inductor's pin spacing does NOT match the stock TDk's. So how to mount it. I thinking leads from the pins to the stock holes will have to work. Not a huge huge deal. however....

2.) I do not know which pins on the TDK are hot and which are the grounds/physical connections one of the 4 pins are not soldered to a pad so that rules one pin out.

3.) Original carbon comp resistors. The bundle I bought from www.dandyjob.com includes a nice sturdy ICAR taper pot and some alternate value resistors. Should I keep the stock resistors as they are original?

If anyone has done this before and can offer some insight I would appreciate. There is little documentation or info on the web. I did this mod for a friend's 90's crybaby and no issues as there's ample documentation for modding that model. It sounded way more musical.

[thermionix]

I bought the Whipple bundle also for my wah build.  I didn't care for the pot, kinda weird taper and it got noisy quickly.  I like the inductor okay, but honestly I'd rather have a TDK.  My favorite is the stack of dimes, but the TDK is damn near as good.  Initially I had transistors with too low hFE, and that gave me a thin/bright tone that I tried to correct with cap and resistor mods (I tried a bunch), but getting the transistors right made the stock circuit sound good.

[MovingInSloMo]

I've never been satisfied with the stock TDK. It just seems thin and lackluster. But again as you mention it could be lame transistors. I'll try out this inductor and see how she sounds. having trouble figuring what pins of the TDK are the live pins.

[MovingInSloMo]

ok now we have issues. it is currently back to stock with the TDK, but however it only wahs through half the pots travel then abruptly cuts off. Anything I might've fudged in the thing while soldering/desoldering? There is a pad under the inductor that seems to be there for only mechanical connection that fell off, shouldn't affect the inductor at all as long as the love pins are soldered.. hmm This same exact issue happened with the whipple, and the new pot.. what is going on now..

[thermionix]

it only wahs through half the pots travel then abruptly cuts off

Is this happening with both pots?

I've never been satisfied with the stock TDK. It just seems thin and lackluster. But again as you mention it could be lame transistors.

I can see how some would describe the TDK as lackluster.  I would call it mellow.  All depends on rest of rig and personal tastes, etc.  The Whipple is definitely more...extreme.

"Thin" sounds more like a transistor issue or maybe a cap has gone funky or a resistor drifted too far.  If the electrolytic cap is original, might be overdue for replacement.

[italianguy63]

I know you may want "vintage" parts...

But, I have rebuilt a pretty good number of wahs.. in my travels, I found that the inductors wound by Joe Gagan (DIY member) are amazing.  It is all I use anymore.

MC

[MovingInSloMo]

it only wahs through half the pots travel then abruptly cuts off

Is this happening with both pots?

I've never been satisfied with the stock TDK. It just seems thin and lackluster. But again as you mention it could be lame transistors.

I can see how some would describe the TDK as lackluster.  I would call it mellow.  All depends on rest of rig and personal tastes, etc.  The Whipple is definitely more...extreme.

"Thin" sounds more like a transistor issue or maybe a cap has gone funky or a resistor drifted too far.  If the electrolytic cap is original, might be overdue for replacement.

Yes both pots, and both inductors. I was wah-ing normaly albeit thin sounding before I touched the iron to it. FIrst thing I replaced was the pot as I had to figure out how to orient the whipple and now I was going to mount it.

I didn't even think about the electrolytic, it's the original cap. Probably due for replacing. Anyone know offhand what value?

[thermionix]

Anyone know offhand what value?

Originally 4uF NP.  Quite difficult to find these days.  Newer crybabys and clones usually use 4.7uF.  Polarized works negative to ground.  Not sure if there's any advantage to NP, and if not, why they used those originally.

[MovingInSloMo]

This old board is just falling apart. The crusty old solder posts and nasty old solder and fraying wires (originally twined together! Love that old skool) are not holding up. Losing pads suck too. I'm being tempted to just buy a new DIY board and start from scratch. The case is already a replacement and I would like to have onboard power. This thing was never collectible and and would be easier to use a modern board with a modern mod-friendly layout. Recommendations anyone? 

[thermionix]

Recommendations anyone?

Perf.