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Author Topic: Voxer '49 - CD4049UBE-based preamp  (Read 4873 times)

blackcorvo

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Voxer '49 - CD4049UBE-based preamp
« on: February 23, 2014, 01:16:26 PM »
Hello there guys! I'm back with yet another strange idea: a CMOS-based preamp. Specifically, I'm using the CD4049UBE, and this is the circuit I ended up with after a good couple of days playing with values.

Here's the schematic:

https://24.media.tumblr.com/6c7488cbc33f0f0085410e599d359fcc/tumblr_n1gmusrwOY1r4gqjso2_1280.png

It's pretty much just a Runoffgroove "3 Legged Dog", but without the input JFET booster, and  the addition of a tone control.

I went ahead and recorded a few samples using Audacity, and just to have an idea of what it might sound through a guitar cab, I used Amplitube to simulate a 1x6 combo cab, and a 2x12 Vox-style cab. Both cabs were recorded with a Dynamic 57 right at the speaker, in the cone position. The tonality change is made via the "Mic" control on the circuit, going from brighter to darker (on the knob, in the order 0, 2.5, 5, 7.5 and 10).

First, the original dry sound: https://soundcloud.com/corvolino03/sets/voxer-49-dry
1x6 cabinet simulation: https://soundcloud.com/corvolino03/sets/voxer-49-preamp
2x12 cabinet simulation: https://soundcloud.com/corvolino03/sets/voxer-49-preamp-1

And last but not least, a PCB layout made in DIY Layout Creator:

https://31.media.tumblr.com/ef2b084f91651e705a178fea2fa87f97/tumblr_n1gmusrwOY1r4gqjso1_1280.png
« Last Edit: February 23, 2014, 01:18:13 PM by blackcorvo »

J M Fahey

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #1 on: February 23, 2014, 02:09:51 PM »
Cool  :dbtu:

Sounds quite usable even dry, go figure, but the speaker simulation definitely smooths things up.

Thanks  :cheesy:
« Last Edit: February 23, 2014, 02:17:52 PM by J M Fahey »

blackcorvo

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #2 on: February 23, 2014, 02:29:06 PM »
Cool  :dbtu:

Sounds quite usable even dry, go figure, but the speaker simulation definitely smooths things up.

Thanks  :cheesy:

Thank you! I'm thinking of having it drive a TDA7240 and powering everything from a 12v 7Ah sealed battery I got here. I'm really loving the sound of this little preamp!

HENK

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #3 on: February 24, 2014, 07:11:21 AM »
 :dbtu:

HENK

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #4 on: February 24, 2014, 05:56:40 PM »
Morning,
there´s something Different:
In the Schematic the Input is:22N-1M to Earth-12OK.
In the Layout it´s:                22N-120K-1M to Earth.
What´s Wrong-what´s Right???
Thanks for Correction! :tu:

                                                   

blackcorvo

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #5 on: February 24, 2014, 10:03:39 PM »
Morning,
there´s something Different:
In the Schematic the Input is:22N-1M to Earth-12OK.
In the Layout it´s:                22N-120K-1M to Earth.
What´s Wrong-what´s Right???
Thanks for Correction! :tu:

                                                   

The layout is the correct one, since I made it before I went to draw the schematic.
However, both ways work just the same, so it doesn't really matter which one you choose to do.

blackcorvo

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #6 on: February 26, 2014, 10:39:47 AM »
I liked the sound of it so much that I went ahead and made another layout with an included TDA7240 power amp:

https://24.media.tumblr.com/9ec40fccff201617e181e4b7119f6e6a/tumblr_n1lytqCkXy1r4gqjso1_1280.png

https://31.media.tumblr.com/0a481753a3a723fc41d1e71df5f8048f/tumblr_n1lytqCkXy1r4gqjso2_1280.png

I'll be making it on a perfboard and I'll let you guys know if it works (I never have luck with chip power amps... hopefully I don't fry this one).

[UPDATE]

Fried the first TDA. Cause of death: reversed power supply polarity. Oops.
Went out to buy a new one (and a couple of spares), soldered it in and BAM, it worked right away! Sounds amazing, and LOUD!
« Last Edit: February 26, 2014, 05:57:11 PM by blackcorvo »

HENK

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Re: Voxer '49 - CD4049UBE-based preamp
« Reply #7 on: February 27, 2014, 04:13:14 AM »
And its for the 4069!

 :dbtu:
« Last Edit: February 27, 2014, 04:15:33 AM by HENK »

 

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