hardwiring an effect into an effects loop?

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Saddlebacks

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im trying to convert my combo into a half stack, and i have this graphic equalizer that i would like to incorporate into my head. I run the graphic equalizer in my effects loop, but the jacks for the effects loop are on the front of my amp, and i think it would look ridiculous having wires coming from the back of the head going to the effects loop jacks on the front then back into the head...

so i figured why not just figure out which soldering points are positive and negative and just hardwire the lines to the circuitboard...


but my problem is the mono effects loop jack has 4 soldering points.... 4!

i have no idea what the other 2 points are for, and which 2 points to hardwire my wires to...


im sorry if ive been a little vague, but thats as best as i can put it...

any advice is appreciated






oh and, does anyone know any reliable sites for buying speaker out jacks (under 400 watts), and speaker grill cloth?


thanks
 
It has 4 connections- 2 for the out and two for the in. The loop sends the signal out to a piece of gear, and then the signal comes back to your amp. You need to figure out which ones are which.

If there is room, why not just move the jacks to the back? Seems like having it hardwired would be a pain. In either case, be aware that where the wires are routed may be important to keep the noise down.

As far as jacks and cloth, Weber has a bunch of stuff, as does Magic Parts (their site seems to be down right now).
 
As stated before, each jack has 2. Positive and ground. I would also agree that the best bet would be to move the jacks to the back side for a very simple reason. *resale value* Its much easier to ditch th amp if you ever choose to if they don't have to buy a hardwired EQ. Though you are making this into a head, so it might not make a difference at all anymore.

But still, the jacks might be soldered onto teh PCB, but any way you cut it, it is more versitile to have them in the back. Take a sharpie and mark "I+, G, O+, G" onto the PCB so you don't muck it up. Get a center punch ($4) so you can drill a nice centered hole (3/8" normally for jacks) on the back side...if you choose to do that.

If you can take a picture we can tell you what is what for connections, but normally an enclosed jack has the positive as the furthest reaching lug. If it an open jack then just look for what connects to the center hole of the jack, that would be ground.
 
well what i meant to say was that each jack (i.e. effects loop send) has 4 points soldered to the circuit board, and the effects loop return also has 4 points soldered to the circuit board, but i think im going to go with the back-mounting strategy...


what kind of wire should i be using?



and is it any different to solder a wire to a circuit board than it is to solder a jack?
 
Thats an interesting jack. I have seen ones with 2 grounds and 2 positives, but that was just so that you could rig 2 connections to the connection without having to use the same lug...that and stability/routing options when mounting onto a PCB.

Normally I would look at that picture and think its a Tip/Ring/Sleeve, but since its mono, I can't really say. I would still bank on the single lug on the back side (lowest in the picture) as being the positive. But luckily if you can reuse the ones that are already there if you desolder them. Just mark down which connections goes where, then wiring it back to its spot.


As for wire? Maybe 20 gauge braided.

The solder is important. Use rosin-core.

Do you know how to solder? You have to heat the connections up before you add solder or you will risk getting a cold solder join and the signal can have trouble getting through.


If you give the model number and any other info (check the internet for a link to the schematic) then we can maybe look it over for you and see exactly what the 4 connections are. Does the amp have a footswitch or bypass of any kind for the effects loop? Because it could be for making/breaking the loop.
 
i have the schematic at http://www.fender.com/support/amp_schematics/pdfs/Ultimate_Chorus_Schematic.pdf

there seems to be only 3 used solder points on the mono channel... but 3 still doesnt make much sense to me




ive soldered several things before and i basically have the jist of it... but when ive tried soldering connections onto the circuitboard before, i always burned it ...should i just heat up the wire then stick it through the point and then apply the solder?


i think that makes sense..






and another question... can i use regular guitar 1/4th inch jacks for speaker outs, or do i need a higher wattage designed jack? Cause i can get them from stewmac.com which is a site ive been to before and trust, but they dont sell any guitar amp hardware...
 
Okay, problem solved. The linked picture is BS, the schematic is what matters.

The schematic says "stereo effects loop". (See section C-1 of the PDF link)

Thats what I though. Its a Tip/Ring/Sleeve connection.

So if you only use mono cables, the Tip is used and the Ring gets grounded out to the Sleeve.

So if you look at the jack you have 3 "areas". (using the pic as reference) The top one is the ground, the middle two are the Ring (you probably only have one of them connected I bet, but if you use a stereo effect, this is the right channel), and the bottom one is the Tip (or main
connection).


Yes you can use regular guitar jacks for effects loops or speakers, but they would need to be stereo in this case to retain the full functionality of the loop.

You can get them at StewMac, but they are probably over priced since they are going to be probably be marketed as "replacements". Don't quote me on that though, I am too lazy to check their site right at the moment.
www.tubesandmore.com will probably be a bit cheaper I think, but www.smallbearelec.com will be cheaper than them all. Their shipping is $3.75 in the US, until you hit the max weight limit and then it goes up based on the total weight of the items you are ording. Not bad IMO. ;)

I wouldn't pay much more than $2.00 per stereo jack. Switchcraft is an ecellent brand. In fact you might want to get new ones since the ones in the picture have crappy plastic threading. :/ Since they won't be held in place by a PCB anymore you will no doubt like the metal threads because you are gonna want to tighten those suckers up hard so they don't come loose (and they will if they are not secure or tightend good).

For soldering, you shouldn't have to hold the iron on the spot much more than 2-4 seconds. Then pull it away and get the solder in there quickly. Get some desoldering braid to unhook these from the PC board.​
 
well wait now...

my amp has both a stereo effects loop and a mono effects loop... look in section D2,


so im still quite lost




but... if i wire lines from the existing jacks to the spots where they originally were (im going to be moving the jacks to the back of the head) ... i should have no problem with this right? and it really wont matter what is negative and what is ground and what those other points are for if im just hooking up connections right?
 
Saddlebacks said:
well wait now...

my amp has both a stereo effects loop and a mono effects loop... look in section D2,


so im still quite lost




but... if i wire lines from the existing jacks to the spots where they originally were (im going to be moving the jacks to the back of the head) ... i should have no problem with this right? and it really wont matter what is negative and what is ground and what those other points are for if im just hooking up connections right?
Click to expand...


Yes you could do that.

If you have a digital multimeter you could measure which connections are gettings a signal and which is ground, but I would assume they just used the the lowest connection (from the picture) and the other two are both connected to ground. By the way, which lugs in the picture are the ones connected? And if you can, see if you can follow their traces on the BC board and see if two of them both go to the same spot.

Does the amp have a bypassable (which a physical switch) effects loop? Or is it always on?

Also take a flashlight and look inside the jack. See how many connectors there are. Just out of curiosity.


:The schematic looks like this:
(Assuming the effects loop is bypassed [when there is no cables connected] no matter if the efx loop switch is on or off) (ie: does the amp still play when the efx loop is engauged with no cables connected?)

It could be that the tip connections works like this....

When nothing is connected, the signal from the preamp hits the efx loop send and is split to both the tip and also to a connection by the efx loop return's tip. When nothing is pluged into the efx return, the signal is connected and proceeds to the power amp stage etc etc etc [normal workings like nothing happend]
But if a cable is plugged in, the pin that connects to the efx return cables tip is lifted, thus breaking the connections from the signal that was split to it from before the send, so that the only signal that continues is the signal from the cable.
 
well im not sure if this is what you were asking for, but...



there is no footswtichable control for the effects loop, i suppose this means its always on..

if i plug a cord into the send jack, the sound cuts out until i plug into the return jack..i believe it has the same effect in reverse, though i havent actually tried plugging into the return first...




thanks for all of the advice and thought
 
Saddlebacks said:
well im not sure if this is what you were asking for, but...



there is no footswtichable control for the effects loop, i suppose this means its always on..

if i plug a cord into the send jack, the sound cuts out until i plug into the return jack..i believe it has the same effect in reverse, though i havent actually tried plugging into the return first...




thanks for all of the advice and thought
Click to expand...


Soulds like the jack is a mono with a shunt. I would just stick with the jacks that are in there unless you can find a wiring diagram for what is what on the jack. If you do upgrade you would either need to buy a mono jack with a shunt or the effect loops would be permantly on requiring a jumper cable be connected when no effects are in the loop. (a small cable from the send to the return...like a fake efx chain)


Good luck. Take some pics so we can see how it goes.
 
I just had an idea.


If you ever get sick of the two holes in the front of the amp, you could add a DPDT toggle switch to turn the effects loop on or off and with a 3PDT switch, a 9v battery, a small resistor, and an LED, you could add a light in the other hole to show if the Loop is engauged or not. YOu could take the power from the PowerSupply, but that would need a lot bigger resistor and involve a lot of crap. LEDs don't use much power and are onyl sucking juice when lit...at least in this case.
 
Those are switching jacks. the signal flows across the jack when nothing is plugged in. when you plug something in, it opens the switch and the signal flows out the cable. when you take the cable out, the switch closes and the signal flows to the return jack. If there is nothing plugged into the return jack, the signal flows across the return jack and back into the amp.

As far as what you are trying to do, a guitar rig is no place for a graphic eq, guitar amps are noisey enough without one of those inserted.
 
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