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DIY Stompboxes => Building your own stompbox => Topic started by: mac on October 29, 2014, 07:12:33 PM

Title: Modified Devi Ever Hyperion
Post by: mac on October 29, 2014, 07:12:33 PM
This is a simplified Devi Ever Hyperion.
Two diodes instead of the PNP transistor, and one less resistor.

In a recent post PRR got me thinking about how the PNP transistor works.
I saw a Bazz Fuss with another diode going from B to Gnd.
No need for a negative feedback resistor, a silicon diode's tiny leakage can feed the base.
MPSA18 have more gain than those BC549C I used. That's why I increase Q2 collector, to match the leakage.
The bigger the resistor the tighter the sound.
In a Bazz Fuss a darlington does the job better since it needs very tiny currents in its base.

This is what I have on the breadboard right now,

(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=51715&g2_serialNumber=1)

enjoy!

mac


Title: Re: Modified Devi Ever Hyperion
Post by: matmosphere on October 30, 2014, 10:30:38 PM
How does it sound compared to a Hyperion?
Title: Re: Modified Devi Ever Hyperion
Post by: mac on October 31, 2014, 06:31:14 AM
I'll post a clip soon.

mac
Title: Re: Modified Devi Ever Hyperion
Post by: bobbysatya on October 17, 2015, 11:12:30 AM
Built and verified! Used 2SC9014D with 630-ish hfe for both transistors. 10k resistor for Q2 gives it right amount of gate. With 100k it squeals. I have built the original hyperion but couldn't get it to work. This one saved me from frustation. Thanks Mac!
Title: Re: Modified Devi Ever Hyperion
Post by: mac on October 17, 2015, 04:03:24 PM
 ;D

mac