Arsenio Novo - TubeSound Overdrive

markm · Post by **markm** » 23 Sep 2007, 22:57

This is a circuit that has been around quite awhile.
This could fall into the "Classic" DIY category.
Many have built this simple OD and Many Love it!

https://i17.photobucket.com/albums/b72/ ... LAYOUT.png

https://i17.photobucket.com/albums/b72/ ... ANSFER.gif

grolschie · Post by **grolschie** » 30 Sep 2007, 23:10

Does it sound good? How would you describe it?

MoreCowbell · Post by **MoreCowbell** » 01 Oct 2007, 05:08

grolschie wrote:How would you describe it?

COT-like.

markm · Post by **markm** » 01 Oct 2007, 20:04

MoreCowbell wrote:
grolschie wrote:How would you describe it?
COT-like.

Yeah!
I would agree with that.

guisquil · Post by **guisquil** » 02 Oct 2007, 21:59

Somebody has the vero board layout for this project?

Thanks

madbean · Post by **madbean** » 02 Oct 2007, 22:32

guisquil wrote:Somebody has the vero board layout for this project?

Thanks

This is an awfully simple circuit....why not do your own vero layout?

oldrocker · Post by **oldrocker** » 06 Oct 2007, 21:27

Does it sound similar to Tim E.'s Harmonic Jerkulator? Just curious.

Post by **modman** » 13 Oct 2007, 20:22

http://www.harmony-central.com/Guitar/F ... ldFuzz.txt

In the link you'll find a similar distortion circuit which doesn't feature the NPN PNP pair, but just an NPN, that's the schemo Arsenio seemingly started from in below build report.

From: Arsenio Novo
Date: 04 Jul 95 23:04:50
Newsgroups: rec.music.makers.guitar
Subject: New Overdrive Circuit[/b]

Hi,

I've noted that talk on this echo always comes back to the subject of
overdrive distortion. Whether generated by a vacuum tube amplifier or
a transistor amplifier there seems to be undeniable differences to me
as well.

Lately, I was tinkering with an unusual transistor circuit
configuration I had come upon a few years ago and made a few
modifications to the circuit that turned it into one beautiful
screaming "tube-like" overdrive but without the wall of noise these
things usually make. When pushed it even makes that distintive
"zoo-zoo" sound...!!!

The original circuit was simply a complementary matched pair of
transistors connected so that all the terminals overlapped. i.e. both
bases tied together, emitter of the PNP connected to the collector of
the NPN, and the collector of the PNP connected to the emitter of the
NPN. Thus:

This transistor pair is then biased by 2 equal value resistors in each
of the compound legs, one to the positive supply and the other to
ground common. The signal is coupled to the base pair leg and the
output is picked off either of the other 2 legs.

The result is that the above circuit exhibits the behaviour of a
multiplier over a range of signal values. It basically performs a
sin function: in other words a frequency doubler.

This doesn't have a very good distortion sound though because it is
rather "burpy and buzzy". However, lately I was toying with the
circuit when I offhandedly decided to try doing something to it just
to see what would result.

After adding a large cap from the NPN's emitter to ground the thing
went wild on me... WANGO ZE TANGO! SUPREMO DISTORTION! I then
proceeded to refine the circuit a little more and got a better
understanding of what it was doing.

The final schematic follows but first a couple of notes on the
circuit. The "bias balance" trimmer should be adjusted for a
symetrical clipping threshold of the output signal as viewed on a
scope. Short of this it can be easily set by "ear" for the most
sensitivity somewhere around mid-turn.

The input should be driven by a lo-z stage if your electric guitar
doesn't have a built-in pre-amp. You can alter the emitter capacitor
value in a range from 0.1uF to 1uF in order to obtain various basement
characteristics but I found the indicated value is a good compromise.
The input capacitor should not vary much either though because if it
is made too large the circuit goes balistic and cuts out on the tutti.

"Tube-sound" Distortion Overdrive Circuit:

The operation of the circuit more closely resembles a vacuum tube than
a diode clipper does because of the strong square law characteristic.
This is due to the negative feedback around both base-emitter pairs.
This feedback accentuates the junction non-linear behaviour manyfold.

Thus each transitor drives the other even harder so that the transfer
curve ends up more logarithmic than is typical of a single transistor.
In other words: the clipping is gradual and not abrupt like it is in
the case of a silicon diode. Typically a lot more 2nd harmonic is
produced as well. As a bonus the waveform folds over on itself when
the circuit is overdriven!

Now in the interest of the common good I donate this design to the
public domain for personal use but retain copyright and reserve all
rights for any commercial purpose. In other words build one for you
and your friend but if you have it massed produced for profit I only
ask a fair share.

Please, do try the circuit and leave any comments in private at my
e-mail address: arsenioDOTnovoATmbaDOTorg

[/quote]

RLBJR65 · Post by **RLBJR65** » 13 Oct 2007, 20:38

Looks a whole lot like this. http://www.geocities.com/j4_student/electra.gif

Post by **modman** » 13 Oct 2007, 21:06

RLBJR65 wrote:Looks a whole lot like this.

Yes you are right, but note the difference between Electra and the first circuit - electra lack gain and bias controls. Note also the difference on the collector resistors. Don't know the transistor for the electra, low gain 2n3904?

Anyway it's just a one transistor gain stage, so many difference are not likely to occur except in the setup of bias and gain.

But who is Arsenio Novo?

RLBJR65 · Post by **RLBJR65** » 14 Oct 2007, 13:25

I should have said it started out like the Electra.

DEon't know who Arsenio Novo is but if you Google him all kinds of interesting stuff pops up

oldrocker · Post by **oldrocker** » 14 Oct 2007, 23:52

Would this schematic work to build the Tubesound OD? I know it's a crude drawing.

OK, I just breadboarded this circuit and it's totally cool. Not what I expected at all. All I can say is man that's a '70's sound if I ever heard it. I thought the overdrive was fuzzy yet smooth. Once the trim was set it really sounded nice. So now I have to decide between the Harmonic Jerk or this. So, you guessed it I'll have to build both. I was thinking of using them both in the same box. The HP as a rhythm and the Tubesound for the lead sound. Just thinking out loud.

pz · Post by pz » 18 Oct 2007, 08:41

Yesterday i tried this little circuit on my breadboard. After some tweaking i got very nice overdrive sound. Cleans up very well and works great with guitar volume pot. Here's the schem i used:
schematic
and here's a sound sample:
sound sample - 650kB. PRS SE->OD->Pandora PX4D as speaker sim->Compact4->PC. Mixed in Reaper. Bass guitar is the same guitar but shifted down one octave with pandoras octaver. Musically poor, but i think that it shows the overdrive structure.
I think adding another one OD stage will make a screamin monster from this circuit. I'll defeinitely try it and post the results.

DougH · Post by **DougH** » 18 Oct 2007, 11:35

That sounds great!

I've never heard of this one before.

gnognofasciani · Post by **gnognofasciani** » 18 Oct 2007, 11:44

DougH wrote:That sounds great!

I've never heard of this one before.

Freakin' good!

pz · Post by pz » 18 Oct 2007, 12:34

thanks

here's another sound sample. This time only one guitar. I tried to play some different techniques to show how does this circuit respond to picking and what is the gain range. Again - PX4d used as speaker sim. with a touch of reverb.
sound sample 2 1.8MB

I tried cascading two of such circuits, but the sound was to muddy, to much gain and compression, even when i put the voltage divider between the stages to take the signal a little bit down. With only one stage this od sounds great, probably would be good as booster too.

polarbearfx · Post by **polarbearfx** » 27 Oct 2007, 07:16

any layouts of this circuit?

Barcode · Post by **Barcode** » 27 Oct 2007, 07:34

polarbearfx wrote:any layouts of this circuit?

um, markm's layout, the one in the very first post

polarbearfx · Post by **polarbearfx** » 27 Oct 2007, 07:46

yeah but I don't etch.

tuemmueh · Post by **tuemmueh** » 27 Oct 2007, 11:18

a) start etching
b) ask somebody to etch it for you
c) use the layout on perfboard

yeah, it really is that simple

Arsenio Novo - TubeSound Overdrive [documentation]