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Solid State version of a VOX AC-30 Guitar Amp

Started by GB, January 08, 2017, 03:53:10 AM

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GB

Hi people... I would like to get a few comments please...
Some time ago I started building custom Guitar Amplifiers... not because I am a Muso... but rather because my (then teenage) son was.

Fast forward 15 years...

I have most recently completed a few different versions of a Solid State Guitar Amplifier modeled on the (classic) VOX AC-30. Its key attributes are:-
1.   Does not use ANY Integrated Circuits (in the signal path)
2.   Does not use ANY bi-polar transistors
3.   Uses FET semiconductors throughout ... JFET's (small signal) and specialist MOSFET's (power)
4.   Amp architecture / signal path / tone controls based on the (classic) VOX AC-30 amplifier
5.   Uses an Output Transformer... like ALL Valve Amps... which provides significantly tonal differences to direct-coupled circuits
6.   Output Damping factor of transformer is much "looser" than solid state amps
7.   Lower damping factor substantially changes the dynamic characteristics of the speakers
8.   Is switchable between Class A(?) (like the VOX AC-30) and Class B for more "conventional" operation. This provides some tonal differences liked by musicians (Clean / Crunch)

While I could write lots more I will perhaps wait for any specific questions and/or general interest first.

Thanks

phatt

Hi GB, and welcome,
So when do we get to hear the sound samples? 8|
Oh yeah,,, where did you get the idea that AC 30 was class A?
Unless I've read all wrong they where All AB1 ;)
no matter,, as long as it sounds good. :tu:
Phil.

aquin43

Sounds interesting. I think that we will need to see the schematics so that there is something to discuss.

Arthur

J M Fahey

Same here   :)
Please at least share some pictures but specially sound samples or maybe a YT video  :tu:

The strawbery on the cake would be some kind of schematic  :dbtu:

joecool85

I'd love to see some pictures and sound clips along with schematics!
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

galaxiex

+1
I'd be interested to see more details and schematic.  :)
If it ain't broke I'll fix it until it is.

bradosaurus

Yes, please! I'd love to see what you've done on a schematic and hear how it sounds! How well do you feel that you've replicated the sound of the AC30? What led you to entirely avoid IC's and BJT's?

J M Fahey

We are talking to the sea waves, the OP dropped his bomb and left for good. Has not even checked the Forum to see whether somebody read his post or not.  ::)

phatt

Oh the Argentine Falcon does not miss much,  8|

Well who knows?
Anyone's guess,,Maybe he stepped outside right after posting and got struck by lightning and now the world will never know if he cracked the code or not.
Phil.

Loudthud

#9
Looks like GB started a similar thread on DiyAudio and posted a couple of reply's.

http://www.diyaudio.com/forums/instruments-amps/301909-solid-state-version-vox-ac-30-guitar-amp.html

Post Edit: Schematic posted in the above link

smackoj

I guess he meant some other kind of "interest" other than people responding to his post?

phatt

Quote from: Loudthud on January 13, 2017, 04:58:57 PM
Looks like GB started a similar thread on DiyAudio and posted a couple of reply's.

http://www.diyaudio.com/forums/instruments-amps/301909-solid-state-version-vox-ac-30-guitar-amp.html

Post Edit: Schematic posted in the above link
Yes thanks for the link and the schematic is there,,,,, but you have to be a member to see the circuit.
Phil.

J M Fahey

No problem, I´ll copy there and paste it here :)

phatt

Quote from: J M Fahey on January 26, 2017, 12:56:41 AM
No problem, I´ll copy there and paste it here :)
Yes I thought that also but was not sure ,, thanks,, Phil.

J M Fahey












hope you can see them; if not I´ll try something else :)