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DIY Stompboxes => Building your own stompbox => Topic started by: cab42 on April 19, 2025, 02:36:39 PM

Title: Built a headphone amp, Poor mans omnibox
Post by: cab42 on April 19, 2025, 02:36:39 PM

I needed a quick and headphone amp for my Christmas holiday. I have always been fascinated by Vigilante397's Omnibox (Thread here (https://www.diystompboxes.com/smfforum/index.php?topic=120628.0)), and wanted something similar, that was less complex and could run on battery.

I looked through my Box of Abandoned Circuits to see if I had something already finished, and found a ROG Fetzer Valve (version 1)

(https://runoffgroove.com/fetzervalve.png)

and a very simple cabinet simulator, the most simple presented in this thread (https://www.diystompboxes.com/smfforum/index.php?topic=106185.msg959449#msg959449) The schematic seems to have disappeared from the thread, but I found a printed copy in a binder

(https://i.postimg.cc/R3q5VHtM/temp-Imagej4u-Z48.avif) (https://postimg.cc/R3q5VHtM)

This is the Vero layout (https://www.diyschematics.com/schematics/galleries/Cab42s-layouts/2NPNCabSim/CabSim.jpg) I made back in the day..


I chained them together and added the headphone amp part of the Omnibox on a piece of perf as well as an aux in between cab sim and amp using simple, passive mixing

(https://i.imgur.com/l7LisnZ.png)

I posted an image of the finished build earlier today in the Pictures thread (https://www.diystompboxes.com/smfforum/index.php?msg=1298029)

(https://i.postimg.cc/4xmQyxFH/temp-Imagebtn-H7h.avif)

It actually sounds great and almost noise free using at battery. Maybe a bit bright. And the battery lasts forever! 

I know this is not something new or groundbreaking, but someone might find it useful
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: Matthew Sanford on April 19, 2025, 05:20:23 PM
Thank you for posting it! After seeing it, thinking about breakfast jam (mmmm...delicious!), looking at my intercom amp w/o headphone jack got me thinking on the NE5534s I have sitting around. Maybe I'll use this with 2!
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: fryingpan on April 19, 2025, 06:37:51 PM
Why inverting?
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: PRR on April 19, 2025, 08:09:39 PM

(https://i.postimg.cc/RWGqqFWT/1964-GE-HP-Amp.gif) (https://postimg.cc/RWGqqFWT)
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: duck_arse on April 20, 2025, 10:49:26 AM
do you get a good ground with that enclosure?
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: fryingpan on April 20, 2025, 11:02:39 AM
Quote from: duck_arse on Yesterday at 10:49:26 AMdo you get a good ground with that enclosure?
Why shouldn't he? A lot of amps have the equivalent of a tin can as a shield (a thin sheet of metal around the circuitry to act as chassis, then mounted into a wood cabinet).
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: duck_arse on April 20, 2025, 11:04:15 AM
look at the label.
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: Fancy Lime on April 20, 2025, 04:09:09 PM
Quote from: duck_arse on Yesterday at 11:04:15 AMlook at the label.
It's not a proper dad-joke, if you don't have to explain it :icon_lol:
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: cab42 on April 20, 2025, 04:42:40 PM
Quote from: Fancy Lime on Yesterday at 04:09:09 PM
Quote from: duck_arse on Yesterday at 11:04:15 AMlook at the label.
It's not a proper dad-joke, if you don't have to explain it :icon_lol:

Well, I didn't get it before it was explained. I was ready to pull out the multimeter and read up on ground in amps  :icon_redface: 
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: fryingpan on April 20, 2025, 05:05:13 PM
Touchè.
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: bluebunny on April 21, 2025, 08:35:28 AM
I got your joke, mate.  ;D
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: bluebunny on April 21, 2025, 08:45:23 AM
Quote from: Fancy Lime on Yesterday at 04:09:09 PMIt's not a proper dad-joke, if you don't have to explain it :icon_lol:

When does a joke become a dad-joke?

When it becomes apparent.





(Getting my coat...)
Title: Re: Built a headphone amp, Poor mans omnibox
Post by: duck_arse on April 21, 2025, 10:44:37 AM
Quote from: Fancy Lime on Yesterday at 04:09:09 PM
Quote from: duck_arse on Yesterday at 11:04:15 AMlook at the label.
It's not a proper dad-joke, if you don't have to explain it :icon_lol:

thanks. now I know.