DIY Signal Saturator....

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Ianbryn11

Active member
Joined
Oct 19, 2010
Messages
29
ok, just an idea i figured id throw out to you smart folks around here... I wouldnt think it would be that hard to do... But im new at this stuff, so correct me if im wrong... you know how on certain pre amps you can crank the gain, and back off the input.. Adds harmonic distortion... How difficult would it be to create a unit to run your signals through so you can saturate the sound? maybee make 8 channels of it... If you have ever used a purple action compressor without compression happening, that sound is similar to what im trying to achieve... Any input?
 
ok, I never used a purple action compressor, but if thats what you want than build 1, see if it is good and build another, do you really need 8 channels? if'n you want overdrive options, build a little box with some attenuators, that can be patched in to pad down the outputs of whatever gear, maybe throw a switch on it so you could insert a variety of transformers pre attenuator.
this way you can run your gear hotter. as far as a circuit, each one is different some clip nice some ugly.lots of options out there, new kits and projects, or cannibalize old pa gear for gain blocks.
this topic is certainly not new. look how classicapi do their preamp with a 600 variable pad on the out: lets you dial in some drive options. similar things with the 'neve mods' putting pot on secondary of input transformer or fader/pot on output. G9 project has gain and level controls...other gear has nice character too, and perform additional spectral or dynamic processing functions (1176 or eqp). no magic bullets, just 'colors' .....why do blocks of 8 of something seem sexier.
have you looked at the tape saturator thing offered in the white market by Sound Skulptor?
 
A vocal fx strip is one of the projects that I have on my list of to-do items...  right after the germanium preamp (which pcb is in the mail to me now).

I was thinking along the lines of compressor -> exciter -> distortion -> tone control, all on one pcb, though I could probably combine the exciter/distortion by switching out a circuit or two.  Any ideas?

regards, Jack
 
Since there is not so many comercial products yet that deals with distrortion, this is a good diy project.
Distortion comes in many flavors ( as pedal builders know) so this boils down to taste and use.
There is alot of info here on the subject, and some spesefic projects.
http://www.groupdiy.com/index.php?topic=38252.0
http://www.groupdiy.com/index.php?topic=36670.0
http://www.groupdiy.com/index.php?topic=41509.0
These are all tube related, but do a search...

If I find the time, I would try a unit with pre and post EQing, and the usual suspects, diode clipping in feedback or to ground, fets and CMOS.
But my next to do thing is a BA-2 with three stages, like EMRR suggests, for vocal work.
J
 
cool, thanks for the relpies... and the links! I wouldn't mind trying to do something in 500 series, kinda nice to not have to deal with the rack, and enclosure.... im sure there are lots of cool possibilities for distortion or saturation effects for that format...
 
wow, they're even nice enough to put the schem up, so perhaps you can use that as inspiration and do your own twist.

http://www.xqpaudio.com/xqp-545-schematic-2.0-sc.pdf
 
Moses said:
Hi,

Ill email a copy of the SPL Charisma to the group DIY account... Might be what you're looking for?

Mo

The SPL Charisma sounds very interesting.. definitely close to what i initially had in mind.... thanks!
 
Yeah, it's not too bad... Power supply in it struggles a little (I had to change a power transformer out that had heat bubbles, which I discovered after it stopped working!), but it works just fine! Also, experiment with the tubes. I have a Groove Tubes ecc83, and a Mullard Ecc81 which has a very different character (much less distortion, much more 'warmth')...
 
I've often had similar thoughts... I think the DIY guitar pedal market may be worth looking at?  AMZ-FX probably has some great projects/ideas.

This article here has some discussion on vocals and distortion: http://www.soundonsound.com/sos/oct03/articles/vocalfixes.htm

Shane D Wilson (Nashville engineer extraordinaire) runs a parallel mix of drums through a Marshall 4x12 simulator for extra harmonic content.  It works, has to be subtle of course.

One trick that I use almost always (on male and female vocals) is to run them in parallel through a 12AX7 software preamp (thingy) with a fair bit of shelving high and high mids boosted (along with compression) - no lows.  Very subtly added underneath the dry vocal.

Mind you... the Dolby 360/36x mod with the Cat 22 mod almost completely replaced a ton of what I would typically do with compressors, eqs, and distortion (in parallel) on vocals.

I'd love to see where this all leads.

CC
 
The charisma looks useful and simple.
Will work on an eagle pcb over the Christmas break.
There's a similar circuit in some Allen and Heath desks that include a mic pre amp for gain also.
 
Does anyone know the value of the output pot?  Also, are the 'lytics on input and output really necessary?  Haven't checked SSM sample circuit but was curious.

Thanks, Nathan
 
Not sure how "desirable" would be that kind of distortions, but how about a circuit with jFET or MOSFET driving a transformer without blocking capacitor? The DC will kick the heck of saturation out of a small core transformer with no air gap. Or make a stand alone unit consisting of a transformer with high permeability core (I think even ferrite should be fine) and a variable DC supply. You could feed variable DC through the Pri to "regulate" the amount of distortions. The 1:1 with ferrite core will be very cheap to make. I could make it bifilar, or two chambered.

Best, M
 
Marik said:
Not sure how "desirable" would be that kind of distortions, but how about a circuit with jFET or MOSFET driving a transformer without blocking capacitor? The DC will kick the heck of saturation out of a small core transformer with no air gap. Or make a stand alone unit consisting of a transformer with high permeability core (I think even ferrite should be fine) and a variable DC supply. You could feed variable DC through the Pri to "regulate" the amount of distortions. The 1:1 with ferrite core will be very cheap to make. I could make it bifilar, or two chambered.

As far as I understood it, that's how the http://www.soundskulptor.com/uk/sts.html stereo tape simulator works. Pre- and post-filtering for the transformer, with good I/O buffers/drivers. Although I'm not sure if the STS is simply overdriving the transformer with loud VAC audio signal. Might be worth it to experiment with the highly asymmetric variable DC distortions as well.
 
Kingston said:
Marik said:
Not sure how "desirable" would be that kind of distortions, but how about a circuit with jFET or MOSFET driving a transformer without blocking capacitor? The DC will kick the heck of saturation out of a small core transformer with no air gap. Or make a stand alone unit consisting of a transformer with high permeability core (I think even ferrite should be fine) and a variable DC supply. You could feed variable DC through the Pri to "regulate" the amount of distortions. The 1:1 with ferrite core will be very cheap to make. I could make it bifilar, or two chambered.

As far as I understood it, that's how the http://www.soundskulptor.com/uk/sts.html stereo tape simulator works. Pre- and post-filtering for the transformer, with good I/O buffers/drivers. Although I'm not sure if the STS is simply overdriving the transformer with loud VAC audio signal. Might be worth it to experiment with the highly asymmetric variable DC distortions as well.

Hard to tell, but with the right impedance and ratio transformer you even would not need a buffer.

Best, M
 
Does anyone know the value of the output pot? It's labeled 'RAD P1' on the schematic while the other 2 have printed values.  Also, are the 100uF 'lytics on input and output really necessary?

Thanks, Nathan
 
output_pot.gif
 
Marik said:
Hard to tell, but with the right impedance and ratio transformer you even would not need a buffer.

of course. I meant I/O as in interfacing the thing with the outside world.

Actually this would make a decent output tweak for a tube project. Most tube preamps have a cap coupled transformer output, things are nice and DC-free right before the transformer. Unless we interfere!

Carefully select a bleeding range from, say B+, or 12V utility lines, whatever is most convenient, and feed that to the transformer + side (other is ground) through a pot. That should drive the output to nice controlled asymmetric distortion. Heck, I've a project on the drawing board perfect for this experiment!

Thanks for the idea! :D

PS. this really needs a post-transformer u-pad since we are clipping it and things will be LOUD at that point.
 
Kingston said:
Marik said:
Hard to tell, but with the right impedance and ratio transformer you even would not need a buffer.

of course. I meant I/O as in interfacing the thing with the outside world.

Actually this would make a decent output tweak for a tube project. Most tube preamps have a cap coupled transformer output, things are nice and DC-free right before the transformer. Unless we interfere!

Carefully select a bleeding range from, say B+, or 12V utility lines, whatever is most convenient, and feed that to the transformer + side (other is ground) through a pot. That should drive the output to nice controlled asymmetric distortion. Heck, I've a project on the drawing board perfect for this experiment!

Thanks for the idea! :D

PS. this really needs a post-transformer u-pad since we are clipping it and things will be LOUD at that point.

Let me know how it worked out--really curious! One thing, you will need to demagnetize the core once you'd like to get back to a "normal" undistorted mode. Not hard, but be aware.

Best, M
 
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