ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  

Shaka HV


 
8/22/2000 6:57 AM
aron
Shaka HV
OK,  
 
Radio Shack sells a 30VDC adapter. It's ridiculous and big and puts out 13.5 or 30V.  
 
I measured it and it puts out....  
 
35.95 DC!!!! I mean, the FET only handles 36VDC right? So we are right there.  
 
I plugged it in and wow.... Now there's too much headroom. There's so much headroom that the 100K pot barely clipped at all.  
 
I put in a 500K pot and that was about 90% of the original 100K pot. I think I could go to a 1MEG pot already.  
 
There's tons of headroom and range.... Maybe too much.... I don't know.  
 
It took a while to get used to. This is the ultimate clean boost pedal. You cannot get this thing to clip if the drive is set low. I mean, you simply cannot.  
 
If you gotta plug a pedal in to AC, then you might as well build the Shaka HV and give it the power it wants cause this thing has all the clean boost you will ever need.  
 
I'm still shocked at how much headroom I have. The adapter can run at 13.5 or 30 so if you lower it to 13.5 you get nice serious distortion.  
 
You guys gotta try this. Unfortunately the adapter is $25!!!!  
 
Aron
 
8/22/2000 11:26 AM
Jake

Sounds great! Does it squash more? or do the diodes to ground just hard clip as they did before. This setup might sound good without the diodes to ground. Also to increase clipping (of MB, anyway) how about a bypass cap on the source of the fet? If it gets to bassy, precede the MB with the 470/470 combo.  
 
 
>>You guys gotta try this. Unfortunately the adapter is $25!!!!  
 
Certainly will, and we could make a little voltage step up board to run this off a nine volt. Now I have to go and check all my capacitor ratings... rrr.
 
8/22/2000 5:23 PM
aron

Jake,  
 
This is the Shaka HV - I have a schematic online.  
 
It doesn't have diodes. I "designed it" in my head so it wouldn't have diode clipping limitations.  
 
> Also to increase clipping (of MB, anyway) how about a bypass cap on the source of the fet? If it gets to bassy, precede the MB with the 470/470 combo.  
 
Hahahaha! Jake, check out the schematic!!!!  
 
You and I should work together on this! :-)  
 
>Certainly will, and we could make a little voltage step up board to run this off a nine volt. Now I  
 
That's the dream.  
 
Aron
 
8/22/2000 9:06 PM
Jake

Had another thought at work. How about running the opamp at 9 volts but the FET at 30 or whatever. Get some crunch from the tl072 and smooth it out with some fet squashing? As long as the two stages are DC decoupled it shouldn't be a problem, right?  
 
The circuit looks cool... I'll give it a try.
 
8/22/2000 9:36 PM
aron

Yep, could do this. I was trying to get less of the TL072 distortion and more of the FET smooth distortion.  
 
I really want to put a variable voltage circuit in there - I think it would be cool.  
 
Aron
 
8/23/2000 5:18 AM
Pete

Aron,  
 
Couldn't you put a smallish resistor in seies with the opamp power supply to lower the voltage to within it's limit. I'm sure a few volts wouldn't make that much difference to the sound (unless you have the opamp's gain set to around where it will clip)  
 
Pete
 
8/23/2000 5:30 AM
aron

Thanks Pete. As I said, I made a mistake. The op amp I used is the RC4558 which does accept +-18 volts (perfect!).  
 
I picked up a voltage regulator and will put adjustable power voltage in tonight!!!!!!!  
 
Hehehehe, dial it in from 9 volts to 36!!!!  
 
This pedal should be killer!  
 
Aron
 
   Page 1 of 4 Next> Last Page>>