Hi!
My small practice amp is an orange crush 12w (CR12L), and although I like it's sound, it lacks a footswitch, or even an overdrive on/off button.
So started thinking about a way to add a footswitch to it.
This amp only has one channel, so the pedal would have to do 2 things:
- Enable the overdrive (clipping stage)
- Lower the master volume a bit (to avoid that when the overdrive is on, the volume getting much louder as well)
The footswitch would activate a relay, and the relay would then connect or disconnect the bits on the circuit.
Any ideas on how I could accomplish this?
If anyone has a schematic for this amp it would help a lot as I cant seem to find it anywhere (I guess the CR10 will be the same).
Thanks :)
If I had it on my bench, maybe in an hour, with good light and my best glasses I might draw its schematic on a piece of paper ... but I don´t, and don´t have any idea as to its schematic.
It shouldn´t be something too complex .. but that alone doesn´t solve the problem. :(
I think your best bet would be, since you are already comitted to build a footswitch, its case, wire it, etc. , go all the way, add a small board and build an actual external distortion pedal.
Why? Because your amp doesn´t really have "a distortion circuit" (which could be switchable) but an extra gain stage which overdrives the regular preamp.
Most expensive parts are the "mechanicals" (case, switches, etc.) I´ve just mentioned; the actual stamp size board with an LM741 and a few parts costs less than U$ 5.
Get the "MXR Distortion+" project at GGG , maybe also in some other sites.
If you don´t want to mess with PCBs, google the Veroboard/stripboard version.
True. It's hard to say anything meaningful without seeing the schematic. Run a forum search on Orange Crush 15 and see if the two circuits have anything in common. If yes, you should be pretty clear on modifications needed to include an overdrive switch.
Even sketching out the schematic and layout of what's where shouldn't take too much time. You need to do something akin to it anyway if you're going to wander into introducing modifications.
All in all, an external distortion box might be an easier solution but of course its not the same as utilizing whats already in your amp.
J M Fahey: Thanks for the idea, that MXR seems actually similar to the overdrive circuit on my amp (there's a dual opamp and two clipping diodes).
Teemuk: I've looked into that cr15 schematic, and it looks very diferent from what I have. I guess the clipping circuit on the first opamp is the same as what I have.
The idea was to keep the original circuit of the amp, but it might not be worth the effort. I guess I'm thinking about this just as a fun project ;)
Quote from: ozzu2000 on November 28, 2011, 04:07:54 PM
The idea was to keep the original circuit of the amp, but it might not be worth the effort. I guess I'm thinking about this just as a fun project ;)
In that case, do what JM suggested and try to draw out the schematic by studying your PCB. Include some good photos of the "guts" of the amp. Between the pics and drawn out schematic, we should be able to help you.
I'll try to make a schematic, it's take some time because this amp is dificult to gain access to the lower part of the pcb (I have to desassemble 6 buttons and 2 jacks in order to remove it from the metal panel).
I'll post photos as soon as I can :)
If you plan to mod it you'd likely need to access the solder side anyway, so what's the big deal?
Well, I'll have to dismantle it, draw the circuit, hopefully get any ideas on how to mod it, then order the components, and only then mod it. All this takes time, and as I only have this amp I wouldn't have any amp in the mean time ;)
Think I'll try to build the MXR distortion + as suggested by Fahey, or maybe just a simple booster could do the trick :)
Quote from: ozzu2000 on December 05, 2011, 06:16:10 AM
Well, I'll have to dismantle it, draw the circuit, hopefully get any ideas on how to mod it, then order the components, and only then mod it. All this takes time, and as I only have this amp I wouldn't have any amp in the mean time ;)
Think I'll try to build the MXR distortion + as suggested by Fahey, or maybe just a simple booster could do the trick :)
Keep it super simple and build my 5th Gear Overdrive: http://www.ssguitar.com/index.php?topic=11.0
Done, built a Thor pedal from RoG :)
Can use it as a clean boost with the set close to minimum, or I can dial it up higher and have some nice overdrive :)
It's my first diy pedal :)
Pics:
(http://i1199.photobucket.com/albums/aa468/ozzu2000/SAM_5290.jpg)
(http://i1199.photobucket.com/albums/aa468/ozzu2000/SAM_5289.jpg)
WOW !!!!!!!!!!!!!!!!!!!!!!
Looks GOOD!
Congratulations!
Very professional.
It´s quite more complex than what I had suggested, but since it came out well, fine.
Now we deserve some MP3s.
Plus 1 from Me,, very tidy work inside. :tu:
But the outside is a bit bland?
If it helps I print Labels straight to normal paper from the ink Jet printer >> Then I spray them with clear Car lacquer >> When dry I just use double sided tape.
Bingo instant Pro looking Water proof Labels.
The Tape is super fine pressure sensitive tape ,, Office supplies should have it.
Comes out looking like this.
Phil.
to J M Fahey: I'll see what I can do about the samples, I'm at the very begining of guitar playing eheh, my guitar playing skills are far worse than my electronics skills ;)
to Phatt: I'll try that, I'm just a bit too lazy at the moment, and just the thought of having to remove all the knob nuts demotes me from doing it ;)
I hope to post something new soon :tu:
Wow, that's the best looking "first try" I've ever seen! MUCH better than my first try...heck, the wiring looks more pro than what I do now!
Those are single core wires, I cut them to correct measure, and bent all the corners before soldering. I did this for all the wires except the ones that connect directly to the electronic board, you can notice that these are not as sharply bent ;) these ones have a guessed length and were first soldered to board, then board put into place, then wires bent and soldered.
I only have one question about pedal. Should the ground be connected to the case?
When I use my amp connected to a grounded outlet everything sounds fine with minimal noise, but if I use an ungrounded electrical outlet, the pedal induces lots of noise :P could this be eliminated if I ground the case together with the guitar ground? (black wires on the photos above)
The metallic pedal case must be connected to the board ground, which is also the ground lug at the input and output jacks, so it works as a shield.
Google "Faraday cage" to understand how it works.
I thought that by leaving the case not connected to the ground I would avoid it functioning as an antenna. Seems that is the other way around :)
Edit: now that I think about it, that's the whole purpose of the shielded cable isn't it? ;)
Isn't there some situation where it's best to keep the case ungrounded? I recall reading somewhere about isolating the ground from the case :P
Update:
Case grounded, noise problem solved!!!! Thank Fahey!! :dbtu:
On another subject, i thought I needed to have my amp on clean setting and the distortion dialed on the pedal only (I though that the overdrive setting on the amp would be added to the one on the pedal), but I just realized the when the pedal is on I can increase the overdrive on the amp knob and the sound doesn't change (head scratch). This way, instead of having only clean and distortion, I can have a bit of chunch dialed on the amp (instead of clean), and when the pedal is on I get the pedal's usual distortion.
I guess this happens for all pedals, but as I've never owned one I just learned this now ;)
Quote from: ozzu2000 on December 20, 2011, 07:33:51 AM
Update:
Case grounded, noise problem solved!!!! Thank Fahey!! :dbtu:
On another subject, i thought I needed to have my amp on clean setting and the distortion dialed on the pedal only (I though that the overdrive setting on the amp would be added to the one on the pedal), but I just realized the when the pedal is on I can increase the overdrive on the amp knob and the sound doesn't change (head scratch). This way, instead of having only clean and distortion, I can have a bit of chunch dialed on the amp (instead of clean), and when the pedal is on I get the pedal's usual distortion.
I guess this happens for all pedals, but as I've never owned one I just learned this now ;)
Hi ozzu,
Regards to solid wire,
Easier to work with but bear in mind it's also more prone to breaking.
A lot of early Valve stuff was solid wire, point to point.
In this case it's already built and looks like it will give years of trouble free service.
But just thought I'd mention that long unsupported solid wire can be a problem with high vibration.
Re distortion ?? Not quite sure what you mean?
The pedal will add distortion on the signal which is then added to whichever channel is engaged on the amp.
Depending on a whole lot of ifs buts and maybes?? It is possible that the distortion may not change much when you engage the amps OD channel.
If that is what you mean? My first guess would be the signal output from the pedal circuit maybe smaller than pedal bypassed.
Some pedal circuits can indeed add much distortion but in doing so loose signal strength.
This can lead to some frustration when jumping between different inputs.
Some Brand name Amps have issues like this with inbuilt OD/distortion where the OD setting is lower in volume that the clean setting. Obviously an oversight in the research department LOL.
And the BIG ONE,,, Try very hard to avoid using Guitar Amps with UN-Grounded power outlets. :grr
Electric guitar is one of the rare situations where the Ground on the Amp is directly coupled to the ground on the Amplifier.
With No earth IF the Amp has a catastrophic failure You could DIE. :duh
Tis very hard to read safety warnings if you are not Alive. 8|
Phil.
Quote from: phatt on December 20, 2011, 09:52:00 AM
Tis very hard to read safety warnings if you are not Alive.
Ahahah, nice one ;)
On the distortion:
"Depending on a whole lot of ifs buts and maybes?? It is possible that the distortion may not change much when you engage the amps OD channel."
That's it.
But I see it as a good thing! Means I can dial a bit of OD on the AMP so I get a little crunch when the pedal is bypassed, and then have the pedal's distortion when I engage it.
(I thought I had to always set the amp to clean in order to use the distortion pedal).
It's like having 2 channels and being able to control OD on each one of them, instead of only having the clean channel and the overdrive channel :)
But like I said, this must be common knowledge to anyone who has used pedals ;)
(quote)
Electric guitar is one of the rare situations where the Ground on the Amp is directly coupled to the ground on the Amplifier.
With No earth IF the Amp has a catastrophic failure You could DIE. :duh
Tis very hard to read safety warnings if you are not Alive. 8|
Phil.
Quote
Whoops!!! :-[
What I meant to say wuz,,,,,
Electric guitar is one of the rare situations where the ground on the *Guitar* is directly connected to the ground on the the Amplifier and hence mains Ground.
Phil.
----
Samples, as promised :)
Recorded though a korg dsp, with compressor and cabinet simulator only.
Dsp connected directly to computer mic input :P
Sample 1: gain at 25%
Sample 2: gain at 50%
The samples are only a few badly played chords, I am a beginner, so no wining about bad skills ;)
gain1.MP3 - 0.40MB (http://dl.dropbox.com/u/40048476/gain1.MP3)
gain2.MP3 - 0.39MB (http://dl.dropbox.com/u/40048476/gain2.MP3)
Very good, thanks. :tu: