Welcome to Solid State Guitar Amp Forum | DIY Guitar Amplifiers. Please login or sign up.

June 13, 2024, 08:01:16 PM

Login with username, password and session length

Recent Posts

 

acoustic guitar preamp

Started by checco1280, December 05, 2009, 04:54:23 AM

Previous topic - Next topic

checco1280

Hi to everyone!!! my name is francesco, I'm from Italy...

I need a preamp for acoustic guitar (with tone stack too) , I think to use a LM3886 for the power stage....

what do you think about?

baene123


checco1280

..e no...ero così conento che una persona mi avesse risposto.... :lmao:

mannaggia sto inglese, che non riesco a far capire una cippa a nessuno....

intanto mi sono documentato...ho in mente una bella cosuccia...ci sentiamo su fennec..... :tu: :tu: :tu:

tonyharker

#3
Please write in English - we would all like to understand what you say!

J M Fahey

Uncalled for, poor translation follows:
>>>>>>>
"ma guarda chi si trova qua! " = Hey!!, look who's here !!!
"..e no...ero così conento che una persona mi avesse risposto.... Funny

mannaggia sto inglese, che non riesco a far capire una cippa a nessuno....

intanto mi sono documentato...ho in mente una bella cosuccia...ci sentiamo su fennec..... "=<<<<<<<<

>>>>>>oh no, I was so happy that (at least) one person answered
#~$#~&* these "english" who can't be understood by anybody
meanwhile I "documented" (searched?) ... I have a "little something" (a good idea?) .... we "feel it" (found it?) in the "fennec": http://www.fennecelectronics.it/ (a DIY electronics site)
<<<<<<<
The somewhat poor Italian original does not help much. ;)

checco1280

sorry...for writing in Italian, the translation by fahey is correct...but my question is still unanswered... :'(

phatt


Hello checco,
                   I've had great success with this one it may interest you.
http://www.ssguitar.com/index.php?topic=1136.0
I take it you wish to DIY a circuit?

Cheers Phil.

J M Fahey

Hi/Ciao Checco. A Ruby amp,http://www.runoffgroove.com/ruby.html ,  with it's Fet high impedance input makes a good preamp, if you use it without the 1K gain trimmer/pot.
It becomes a 20x gain clean preamp. On its output, instead of a speaker you can hook a 1Kohm resistor and reduce the output capacitor from 220uF to 10uF.
You can get 9V from the +35V LM3886 supply with a 1K1W resistor, a 9V Zener and a 100uFx25V capacitor.
If you find it confusing, I can draw a schematic.
Ciao amico e buona fortuna.

phatt

Opp's forgot to say.  I'm assuming your Acoustic guitar has a built in preamp?
If NOT?   Then you need a different setup.
Phil.

checco1280

#9
Quote from: J M Fahey on December 10, 2009, 10:16:32 AM
Hi/Ciao Checco. A Ruby amp,http://www.runoffgroove.com/ruby.html ,  with it's Fet high impedance input makes a good preamp, if you use it without the 1K gain trimmer/pot.
It becomes a 20x gain clean preamp. On its output, instead of a speaker you can hook a 1Kohm resistor and reduce the output capacitor from 220uF to 10uF.
You can get 9V from the +35V LM3886 supply with a 1K1W resistor, a 9V Zener and a 100uFx25V capacitor.
If you find it confusing, I can draw a schematic.
Ciao amico e buona fortuna.

Oh thanks!!!
according to you can I add an active tone stack? like a baxandall? what's its position? Or I need just a passive tonestack?

J M Fahey

Yes, you can also add a Baxandall, between the preamp (Ruby) out and the 3886.
Anyway, start with a passive one that's simpler. Go step by step.
If I remember well: "Piano, piano, si va lontano"

checco1280

"Piano, piano, si va lontano"  ;D ;D ;D ;D
you speak Italian?



checco1280

With a passive tonestack  there isn't too much drop of gain?

J M Fahey

1) Yes, there is a 3x to 4x loss, yet in clean amps many times I could drive properly modern sensitive power amps. Try it, it's free ! (and cheap). If you need more gain, you add what you need. We're talking, of course, *after* your Ruby, not straight from the guitar.
2) Buenos Aires had 60% (not a typo, sixty percent) Italian population in the 20's.
Today it still has over 50% Italian surnames.
I'm unusual here in not having one drop of Italian blood, although .... I married an ... Olivetti .... !! and my son speaks perfect Italian.
Io ne parlo só perche sono faccia di pietra, lei capisce?
Besides, Buenos Aires Spanish, called "porteño" or "lunfardo" is 30% Italian, and we are full of old ladies who still speak "mangia mangia che ti fa bene" , "te amazzo !!!", and 1000 colorful expressions or insults which I can't post here.
And Tango, quite unrelated to original Argentine/Spanish Folkloric music, is "the music made by the Italian Immigrants", uses accordion, piano and violin, most of the great composers were born Italian.

J M Fahey

Hi, he wrote you today, maybe you clicked on the thumbnail and lost the original page. It's:
http://www.ssguitar.com/index.php?topic=1136.0
Phil/Phatt assumes there that you already have a preamp.
You may use the Ruby (clean) into the passive EQ into the power amp.
If you lack gain I'll post the simplest gain block.