collapse

Author Topic: Using Ruby circuit as a preamp (line out ?)  (Read 13617 times)

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Using Ruby circuit as a preamp (line out ?)
« on: May 10, 2009, 12:42:24 PM »
Hi guys !
I'm playing a little with my Ruby amp, wishing to add some features to this little marvel.

One of the options I see is to use it as a preamp, pluggin' it to a old 15Watts' "Dean" amp I have found in a "twilight" zone of my house (a sort of "Lost & Found" room...  ;D )

The question is:
May I plug the instrument in the Ruby and create a line-out connection, which should go to the input of the Dean Amp ?

I've found (inside SSGuitar forum) a link to a line-out schema, which I post here below:



Additional questions:
- Should I use this from the Spk out of my Ruby ?
- Shall I disconnect the spk from the Ruby, or it can remain connected ?
- Can this connection damage the Dean ?

Thanks in advance for your help !

Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3156
  • Chip Points: 985
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #1 on: May 10, 2009, 06:10:58 PM »
I ran my little gem (similar circuit to the ruby, based on the lm386 still) directly into my Dean Markley K-20X with no problems.  I also ran it directly into my LM3886 poweramp, it worked wonderfully for me.  I'm sure others will have opinions on the matter.  I'm currently working on a simple preamp with clean and gain channels based on the lm386.  It's not a good chip for hi-fi (as a preamp anyway), but works great with guitar.
Life is what you make it.
Still rockin' the Dean Markley K-20X
"New" amp: Fender Frontman 25 DSP (FM25DSP)
thatraymond.com

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #2 on: May 10, 2009, 09:33:24 PM »
Hi JoeCool, thks for your comments.

It's good to know that this may work. My only concern was not to damage the amp.
Maybe the output of LM386 is weak enought for non damaging the amp, and according to your feedback "...I ran my little gem (similar circuit to the ruby, based on the lm386 still) directly into my Dean Markley K-20X with no problems..." seems it won't.

Pls, keep us posted once your preamp project is finished !
In the meantime, i'll give a try to this configuration and post the results in the forum.
Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Posts: 4142
  • Chip Points: 429
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #3 on: May 11, 2009, 12:29:35 PM »
Hi Sergscar.
You *can* drive a preamp or power amp input with Ruby´s speaker output and get away with it, only because it´s 9V powered and can´t put out a signal voltage higher that of any other 9V pedal , although at a *much* higher current level.
To play it safe, pad the output with two 10K resistors, one in series with the signal and the other to ground.
This both limits voltage (from almost 3V RMS) to half of it, but more importantly limits current to pedal-world levels.
An even better solution is to replace the 2nd resistor with a 10K pot to get any output level needed; it becomes a Master level.
Bye.

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #4 on: May 11, 2009, 12:59:56 PM »
Hi JM Fahey !
Nice and clear explaination.
So, I'd do this ONLY if running the Ruby on 9V (just as a reminder: LM386 can be powered at a max. of 12V !).
I'll do my homework and post some feedback.
Thanks !
Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Posts: 4142
  • Chip Points: 429
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #5 on: May 11, 2009, 02:14:55 PM »
Hi Sergscar. In fact it´s the other way round: you *can* avoid using it (sort of) with a supply of *up* to 9V (I would be worried even then) but you definitely need to attenuate with higher supply voltages. Bye.

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #6 on: May 11, 2009, 03:42:50 PM »
JM Fahey, hello
You are right. I've just realized that expressed myself bad.
I was willing to say "... void to use it as a preamp if powered with over 9v...".
Anyway, this mistake generated a new light => I can even use it if powering with 12V, however, reducing the output current (maybe I've to use higher resistors).
Sorry and thks again !  :tu:
Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3156
  • Chip Points: 985
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #7 on: May 11, 2009, 07:39:18 PM »
Just remember, runoffgroove.com has two pedals based off the lm386 - the big daddy and the grace overdrive.  They use a 100k pot as a master volume, similar to what JMF posted.
« Last Edit: May 11, 2009, 07:41:12 PM by joecool85 »
Life is what you make it.
Still rockin' the Dean Markley K-20X
"New" amp: Fender Frontman 25 DSP (FM25DSP)
thatraymond.com

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #8 on: May 24, 2009, 03:36:31 PM »
Hi guys,
I've already done the preamp circuitry, as well as tested it with the Dean GTX12.

From the input jack of the Dean (inside the amp), I've soldered 2 wires, which I've added the 2 resistors (10k), as suggested by JM Fahey (see picture below)



In the preamp (Ruby-LM386), I've left the gain "open" (20db Gain), keeping the original 10K linear pot as volume control (see picture below)



I don't know if by doing it this way it should react different than the "better solution" proposed by JM Fahey (replacing the "R2" - 10k resistor - with a 10k linear pot, for acting as a master volume). Comments on this issue ?

The result:
- Much clearer sound from guitar, if compared with original setup
- Louder volume, without necessity to get a higher gain (distortion) from the op amp

Question:
the new setup permits me to run the amp by its original input jack, as wel as through the preamp.
Should I notice any response's difference, in case I decide to use amp's original input jack, considering there's a "bridge" connection (R2 10k, as showed in the picture) between the + and - wires ?

Thks a lot your comments.
« Last Edit: May 24, 2009, 03:41:22 PM by sergscar »
Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3156
  • Chip Points: 985
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #9 on: May 25, 2009, 04:41:24 PM »
So are you able to get a good clear clean sounds even while playing chords with your guitar's volume up all the way?
Life is what you make it.
Still rockin' the Dean Markley K-20X
"New" amp: Fender Frontman 25 DSP (FM25DSP)
thatraymond.com

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #10 on: May 25, 2009, 09:48:24 PM »
Hi Joe,
I wouldn't say "100% clean", but much more clear than before.
- In fact the Dean GTX12 doesn't produce any sound if gain pot set to "0", therefore, there will be some distortion, naturally.
- The treble and the mid seems much more "enhanced" and brighter than originally, but not losing the bass.

So far, I had a very good impression (I just tried it for abt 10 minutes), and after running the guitar directly on the amp (bypassing the pre amp) my son and I had the feeling that the sound was "fuggy", that's why I asked a particular question (quoted here below):

Question:
the new setup permits me to run the amp by its original input jack, as wel as through the preamp.
Should I notice any response's difference, in case I decide to use amp's original input jack, considering there's a "bridge" connection (R2 10k, as showed in the picture) between the + and - wires ?


Well, those are my first impressions, and I'm afraid won't be able to test it further until the next weekend.

If you wish, please ask specific questions abt the performance, and I'll post the results asap.
I'll also try to record some samples, posting it here, for your easy comparision.
Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3156
  • Chip Points: 985
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #11 on: May 26, 2009, 05:06:28 PM »
Excellent, keep us posted!
Life is what you make it.
Still rockin' the Dean Markley K-20X
"New" amp: Fender Frontman 25 DSP (FM25DSP)
thatraymond.com

sergscar

  • Regular
  • **
  • Posts: 45
  • Chip Points: 6
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #12 on: May 31, 2009, 06:19:22 PM »
Hi guys, as promised, here you have the demos:

DEAN GTX12, without preamp => http://www.scarimbolo.com.ar/31MAY091_DEAN.mp3
Preamp => DEAN GTX12 => http://www.scarimbolo.com.ar/31MAY091_DEAN_PRE.mp3

You will notice the difference I've talked about... but, please, forgive my poor performance in the guitar

Doubts/questions, feel free to let me know.
« Last Edit: May 31, 2009, 06:22:35 PM by sergscar »
Guitars: Hondo II Les Paul '79, Crafter FW-770 EQ (steel) '96, Edwards ESP Strato '02, Acoustic Yacopi (nylon) '09, Fender Strat MIM S/S/H '05
Amps: "Scarface" Ruby, Dean DGX-12, Laney TF-200
USB Interfaces: M-Audio JamLab, M-Audio FastTrack Pro
Mic: HSR 3.2 Multipatern Condenser

joecool85

  • SSGuitar Admin
  • Legendary
  • ******
  • Posts: 3156
  • Chip Points: 985
  • SSG Creator
    • View Profile
    • thatraymond.com
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #13 on: May 31, 2009, 08:19:18 PM »
Hi guys, as promised, here you have the demos:

DEAN GTX12, without preamp => http://www.scarimbolo.com.ar/31MAY091_DEAN.mp3
Preamp => DEAN GTX12 => http://www.scarimbolo.com.ar/31MAY091_DEAN_PRE.mp3

You will notice the difference I've talked about... but, please, forgive my poor performance in the guitar

Doubts/questions, feel free to let me know.

Wow, that sounds great!  I'm going to have to build another lm386 just as a test bed preamp and see what it does hooked to my lm1875 amp...
Life is what you make it.
Still rockin' the Dean Markley K-20X
"New" amp: Fender Frontman 25 DSP (FM25DSP)
thatraymond.com

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Posts: 4142
  • Chip Points: 429
    • View Profile
Re: Using Ruby circuit as a preamp (line out ?)
« Reply #14 on: May 31, 2009, 09:29:15 PM »
Hi Sergio.
Incredible difference !!!
The "flat" Dean sounds dull and lifeless; the "SergScared"one is alive .
Congratulations.

 

* User Controls

 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?

* Recent Posts

Z-MATCHER 100W IMPEDANCE MATCHER by Loudthud
[September 16, 2019, 04:42:44 PM]


Hybrid valve and TPA311x by jfetter
[September 13, 2019, 03:29:50 PM]


Marshall 5010 Needs Help by Jazz P Bass
[September 13, 2019, 12:12:27 AM]


Do you need a low pass filter in your amp when you already have the eq? by slimjohnny
[September 11, 2019, 06:01:57 AM]


Gallien Kruger GT200 by mandu
[September 10, 2019, 06:31:10 AM]

* Sponsors