Bliss - Overdrive/Booster/FX Loop

Original effects with schematics, layouts and instructions, freely contributed by members or found in publications. Cannot be used for commercial purposes without the consent of the owners of the copyright.
Post Reply
User avatar
briggs
Tube Twister
Information
Posts: 1971
Joined: 12 Jul 2007, 10:02
my favorite amplifier: Briggs Custom Suprono
Completed builds: Too many to still class myself as sane....
Location: Breaking into Heaven.
Has thanked: 27 times
Been thanked: 128 times
Contact:

Post by briggs »

Here is a new one from me and I need some help.

It's a booster/overdrive/FX loop that I've been playing with. Basically the idea was to create something which would allow you to place your old gain pedals in to add a bit of new life and sparkle to them - this is what I've come up with. It can do some nice boost/OD tones on it's own but when you add (for example) a tubescreamer into it's effects loop that's where you get a whole new range of tones from it. The first pot is a standard sort of bass blend (With some roll off thanks to the voltage divider) and the second is a standard master volume. The switch is a dpdt on-off-on switch which allows you to switch between bright, mellow and dark modes (adjusts the post gain treble roll off of each stage), the negative feedback loops take care of making sure the whole thing is smoothed out a bit.

So, onto the help I need; I would really appreciate it if someone could give this thing a breadboard and test it with their gear and give me some feedback on how it sounds + any tweaks you could recommend. Is it to bright? To dark? Too much gain/not enough gain? Is it just a shite idea?

Anyway, have a play with it - any feedback is massively welcome :blackeye

P.S THE VALUE OF THE FIRST CAP IS 470pF (for some reason I marked it as 470 ohms!) and the 2n5457 fet needs to be biased around 5.5v :horsey:
Attachments
SAM_2861.JPG
Image

I am Klon.

User avatar
mictester
Old Solderhand
Information
Posts: 2923
Joined: 11 Sep 2008, 20:29
my favorite amplifier: Mesa Boogie, Roost Sessionmaster, AC30
Completed builds: Hundreds! Mostly originals, a few clones and lots of modifications.
Location: Somewhat closer to Amsterdam than before!
Has thanked: 32 times
Been thanked: 844 times
Contact:

Post by mictester »

Modified a bit!
Modified a bit!
This is what I tried for the first stage. It's reminiscent of an AC30 "bright" channel, and could be fun into a tremolo unit - very 60s!

I haven't tried it in conjunction with another pedal like you suggest (it's late here and people are trying to sleep). I haven't really done much with the BS170 and now that I've had a play, and discovered what they can do (and that they're remarkably robust for an FET), I'm going to play around a bit more!
"Why is it humming?" "Because it doesn't know the words!"

User avatar
briggs
Tube Twister
Information
Posts: 1971
Joined: 12 Jul 2007, 10:02
my favorite amplifier: Briggs Custom Suprono
Completed builds: Too many to still class myself as sane....
Location: Breaking into Heaven.
Has thanked: 27 times
Been thanked: 128 times
Contact:

Post by briggs »

Cheers mictester, that's some cool little additions there. The cap to stop AM pick up will certainly help as will the input modifications (I've actually configured it somewhat like your diagram by fiddling round with a switchable input cap rather than a blend pot. The switch provides 3 useful positions instead of a pot with 50% of it's rotation useless.). What type of Ge diodes you got there 1n34a? I think I've just about got this design down now. When you add pedals into the loop it's interesting it adds an extra few layers of gain and some interesting harmonics, gives old pedals a new lease of life :block:

I love the BS170, it's a great device, really flexible and has great gain and clipping characteristics. I tend to try and use them in most situations :blackeye
Image

I am Klon.

User avatar
coldcraft
Diode Debunker
Information
Posts: 725
Joined: 11 Jul 2009, 01:00
Has thanked: 38 times
Been thanked: 85 times

Post by coldcraft »

what kind of pedals have you tried in the loop? dirts or modulation or ?
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

User avatar
briggs
Tube Twister
Information
Posts: 1971
Joined: 12 Jul 2007, 10:02
my favorite amplifier: Briggs Custom Suprono
Completed builds: Too many to still class myself as sane....
Location: Breaking into Heaven.
Has thanked: 27 times
Been thanked: 128 times
Contact:

Post by briggs »

Oh, I need to update the schematic for this! I was designing it for a friend who wanted to give his old dirt pedals a new lease of life. It adds a lot of dynamic response to most dirt pedals and a bit of a mid boost too, it pretty much does what I wanted really. I slapped a clone of a BJF Sea Blue Eq in the loop and that worked well, as did adding an envelope filter, there's some really interesting overdrive/filter tones in there.
Image

I am Klon.

User avatar
briggs
Tube Twister
Information
Posts: 1971
Joined: 12 Jul 2007, 10:02
my favorite amplifier: Briggs Custom Suprono
Completed builds: Too many to still class myself as sane....
Location: Breaking into Heaven.
Has thanked: 27 times
Been thanked: 128 times
Contact:

Post by briggs »

Here's the updated schematic - with some changes suggested by mictester:
Attachments
briggs_bliss.jpg
Image

I am Klon.

User avatar
coldcraft
Diode Debunker
Information
Posts: 725
Joined: 11 Jul 2009, 01:00
Has thanked: 38 times
Been thanked: 85 times

Post by coldcraft »

is point A feeding forward or back, I can't really decide.? :scratch:

also, if its negative feedback, and the effect in the loop happens to be inverting, will that turn into positive feedback?
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

User avatar
briggs
Tube Twister
Information
Posts: 1971
Joined: 12 Jul 2007, 10:02
my favorite amplifier: Briggs Custom Suprono
Completed builds: Too many to still class myself as sane....
Location: Breaking into Heaven.
Has thanked: 27 times
Been thanked: 128 times
Contact:

Post by briggs »

coldcraft wrote:is point A feeding forward or back, I can't really decide.? :scratch:

also, if its negative feedback, and the effect in the loop happens to be inverting, will that turn into positive feedback?
it's implemented here as negative feedback, it tames high end later on in the signal. It will boost high end if the effect in the loop is inverting. It creates some interesting effects when you have modulation effects in the loop, my reverb gets an extra layer of ghostly feedback!
Image

I am Klon.

Post Reply