Whirlwind DI to Reamp conversion - Pics

[JohnSuitcase]

OK, you ever get a dumb idea, then not be able t o shake it 'til you do it?

Here was mine. Everyone knows that you can run a passive DI as a reamp, with limited success. Everyone knows that a proper reamp has level and impedance controls. And everyone knows there are schematics out there to build a reamp.

-So, I looked at some reamp schemes, and then thought "Wonder what my WhirlWind DI looks like inside?" So I cracked it open, and obviously, it's pretty simple. I thought, "What the hell, I'll try it!"

So, here's what I did:

-Wire XLR to Input TRS connector
-Scratch out connections to Input TRS, to isolate it.
-Connect "hot" side of transformer (marked with "x") to a 200ohm resistor to ground (I removed the old resistors used for the Pad switch, and put in the 200 ohm one at an angle...)
-after resistor, connect to high side of 1k pot, low side goes to ground
-wiper goes to high side of 50k pot
-high side shunts to wiper
-low side goes to tip of output jack.

Skip/remove pad switch, XLR connector has to stay. The Ground Lift switch still lifts ground.

Now, what was the instrument input is the balanced input from the DAW, what was the parallel out is now the output to the amplifier. The transformer is being used in reverse, of course.

So, I did all that, and it works! But, I feel like the output level is a shade lower than I'd like, and the pots don't seem to have much effect. I took the values from a schematic I found online, but of course, the schem wasn't for repurposing a WW Di.

Anyone care to suggest better pot values? Basically, my output level is a bit low, and adjusting the 'level' pot has little effect. I can't attenuate it to zero output, I'm wondering if 1k is just too small?

Or I possibly crossed something up somewhere. But it does work, I've tested it with my Line6 Toneport, and it sounds quite good, much better than a regular reverse-DI.

Using a proper balanced cable to the input makes a big difference as well!

Here are some pics and the schematic I followed (sort of!)

 

[Svart]

good initiative!

do you have a schemo of the original box?

 

[JohnSuitcase]

No unfortunately I couldn't find one. I do have a second one that's unaltered, though. If I knew more about this stuff, I could probably write the schemo out myself, it's a pretty simple box...

It's the Whirlwind EDB1.

 

[SonsOfThunder]

Mabee try removing the 200 Ohm R1? See what happens!

HTH!

 

[Kev]

no comment


:roll:
except
have fun
and hope you learn some cool stuff along the way

it's all good

 

[JohnSuitcase]

Thanks, I've been just trying to learn some of this stuff in the last month or so (I got a few PM1000 strips I'm about to rack, but thought I ought to try soldering something first!)

I've read a couple of books, and done a couple of simple things (converted RS PZMs to phantom power, and one to use a 9volt), but this is my first wacky idea.

I've found that electronics has the illusion of being very difficult, then appearing rather simple, then becoming very difficult again, but in a different way than I'd thought!

Fun stuff, though!

 

[Kev]

[quote author="JohnSuitcase"] ... (converted RS PZMs to phantom power, and one to use a 9volt), ...[/quote]
which phantom conversion did you use ?
was it from the rosswood site ?

the 9v thing might be nice to add to the site

 

[JohnSuitcase]

I used the info from this site:
http://www.itrstudio.com/pzm.txt

There's info on phantom power (using the 12v Zener diode method listed), and on the 9v power supply approach. To my ear, the 9v one sounds a hair better, but that might just be my shoddy soldering on the Phantom one! I used 'Method 1' for the PZM phantom power.

I'm going to build an electret omni next, using the TapeOp omni plans, but with a few minor variations. I am tempted to try another pass at the phantom power approach though, since it's one less thing to worry about!

 

[Handcrafted Tone]

try picking up a 1:1 transformer to raise the level. Look at the Jensen schematic, it uses a 10k:10K in a very similar circuit.

You can find xicon 10K:10K transformers at mouser for $2 that will fit in that board. A Triad might fit there too, $3 at Digi-key. I've tested both, and it seems the xicon has a better frequency response, with the triad boosting everything over 4K about 6db. The xicon had about 1db boost. The xicon has wire leads that make it easy to fit any footprint.

 

[Svart]

or our friends at Edcor, 10$ for a very good transformer.