EMG 18v mod

[metalchurch]

This morning I did 2 of my KV's with the 18v mod. I've never tried it before, and I've heard and read that it makes no difference either way.

That is incorrect, in fact I like it alot better, because they are more responsive with a tighter upper end, and the sustain is way better.
It also has alot more head room and it sounds less compressed, which is a known trait of the EMG's.

They almost have a passive type of sound in a way, cause they brightened up and came to life, that's about the best way to describe it.

I highly recommend this for anyone, no matter what genre of music you play.
I'm currently working on adding a mini on/off switch to go back and forth from 9v to 18v with a flip of the switch.
If anyone is interested in having this done to their guitars let me know and I'll hook you up.

[JackANSI]

And if you don't have the room for 2 - 9v... There are ways to get there

The way these circuits need to work (since you need a negative and positive supply) is to use a 2x voltage divider then instead of referencing the ground(neg) pole of the battery as zero, they reference the division (which is half of the total supply). So you end up with a -4.5 - 0 - 4.5 supply from one 9v... Unless its a nasty-noisy rail-to-rail, you need to subtract .35v to .7v from that to cover the semiconductor switch losses. So the maximum the output can swing is +/-4V which is idealistic and more realistic is along the lines of a total differential of 3V-4V (+/-1.5V-2.0V).

If you double the source voltage to 18v, you get more or less twice available output or if you do like EMG does and fold that extra headroom into dynamic range and higher available currents, the pickups will sound more alive, and you get about 1 or 2V more output differential. That gets you closer to the output levels of a med/high output passive pickup.

Plus the pickups willl operate closer to their ideal even in adverse situations thanks to the bump in current.


Edit:

Sorry I keep doing that to your posts man... I just get all excited mentally by talk of electron flow

[metalchurch]

That's ok man, atleast someone is replying, the tech sector is like a graveyard. I try to come up with topics, but alot of times they get no replies at all.

According to EMG, their active pickups are capable of handling up to 27v, but they do not recommend it because of the variances in production, like nominal +/- a given # of output level.

I really love the sound of this mod, don't know why I haven't tried it before? I guess if it isn't broke then don't fix it. I'm always working on someone elses guitar and I never make time for my own.

This mod will also work with active bass pickups too, it's definitly worth checking out.

Here's the diagram I have so far:

I'm trying to figure out how to wire this mod to a toggle switch so I can go from 9v to 18v w/ the flick of a switch.

Is this correct?
I have an on/on/on mini toggle with 6 posts; 3 rows of 2 side by side posts. Can anyone help me with this one?

[JackANSI]

Don't use the on/on/on In the middle position you'll be shorting one of the 9v batteries.

just a simple on/on DPST (1 row of 3 posts) would be best.

beware: most EMG's pop pretty bad when you give them power so I would unplug before throwing that switch.


I've tried everything upto 33v with my EMG 40DC/40P5 setup. On an oscilliscope nothing really changed as far as dynamics above 24v. Except at 33v when a hard enough pluck of the strings resulted in a saturated opamp sticking to the negative rail.

All my basses with EMG's are 18v

[metalchurch]

Unplug my guitar? What about the mute button on my tuner, would that be ok?

What can I do to prevent that?

[JackANSI]

A mute on the tuner should be enough. you just want to prevent that pop from going through your amp If your volume is the last thing before the jack, you can turn down there and you should be good.

I know of nothing that can prevent that. Its a transient that the internal pickup electronics make while the opamp's feedback loop is established.

[metalchurch]

Damn that sucks dick, I wanted to be able to 'shift on the fly' so to speak, but that is not gonna cut it.
I can still wire it that way, but I can't use it as intended.

DPST means what? Double Pole Single Throw?
And I need a toggle with 3 posts in a straight line, (on/on)?

What about an on/off? : On=18v, and Off=9v would that work also?

Thanks for the help man!!

[MeYatch]

does this increase the volume significantly?

My fleishman has retardedly low volume, I don't remember if it has EMGs in it or not, but it has active pickups, and only one 9 volt.

[JackANSI]

Damn that sucks dick, I wanted to be able to 'shift on the fly' so to speak, but that is not gonna cut it.
I can still wire it that way, but I can't use it as intended.

DPST means what? Double Pole Single Throw?
And I need a toggle with 3 posts in a straight line, (on/on)?

What about an on/off? : On=18v, and Off=9v would that work also?

Thanks for the help man!!

on/off won't work because they are normally SPST.

In simple switches (you are correct about double pole single throw):
Poles are the points it switches to. in a single row of 3 (DPST) the poles are on either end with a common (the two poles share it) in the middle.

Throws are a count of how many sets of poles there are. in two rows of 3 (DPDT) there is really two switches, both "thrown" by the same lever. think of it as two DPST switches side by side.

You can have as many poles and throws as physically possible.

[metalchurch]

So if I bridged a DPDT it would technically be the same as a DPST?

[metalchurch]

does this increase the volume significantly?

My fleishman has retardedly low volume, I don't remember if it has EMGs in it or not, but it has active pickups, and only one 9 volt.

No, but it creates the illusion that it does, because of the increased headroom and a less compressed signal.

[Ron]

Here's the diagram I have so far:

I'm trying to figure out how to wire this mod to a toggle switch so I can go from 9v to 18v w/ the flick of a switch.

Joe, the bottom schematic in your diagram shows just that, switching from 9V to 18V at the flick of a switch. I'm not sure about the kind of pop you would get when switching it on the fly.

I found it odd that the 18V is wired that way. Apparently they are still using the same voltage divider as normal and just bumping the rails up with a higher input voltage. I wonder how much of a difference it would make to actually tie the wire connecting the series batteries to ground and use the remaining + and - terminals as +9V and -9V. As long as both batteries had the same charge, I would think that the op amp(s) in the preamp would perform at their best and there would be no resistors in a voltage divider to suck away any current or drop any voltage.

[JackANSI]

So if I bridged a DPDT it would technically be the same as a DPST?

Yes, or you could just use one side of it.

[metalchurch]

I kind of follow you Ron, but in this case I would need to see a photo or diagram of what you're talking about.

Your saying to wire the +&- from both 9v's together, connnect to middle post on switch / then the + from #1-9v goes to pickup/ #2-9v negative goes to ground on switch?

Is that what youre trying to say?

[metalchurch]

So if I bridged a DPDT it would technically be the same as a DPST?

Yes, or you could just use one side of it.

Makes sense, thanks.

so what about that diagram? If I have the right switch, is that how the wires should go?

[JackANSI]

Joe, the bottom schematic in your diagram shows just that, switching from 9V to 18V at the flick of a switch. I'm not sure about the kind of pop you would get when switching it on the fly.

I found it odd that the 18V is wired that way. Apparently they are still using the same voltage divider as normal and just bumping the rails up with a higher input voltage. I wonder how much of a difference it would make to actually tie the wire connecting the series batteries to ground and use the remaining + and - terminals as +9V and -9V. As long as both batteries had the same charge, I would think that the op amp(s) in the preamp would perform at their best and there would be no resistors in a voltage divider to suck away any current or drop any voltage.

All batteries aren't created equal, thats why they don't do it that way. Even two batteries right next to each other in the assembly line will discharge at ever so slightly different rates. That leads to an offset (biased) voltage that would be usually carried to the output.

If it wasn't carried to the output the negative feedback on the opamp would carry that current around to cancel it, drawing more current to do it, thus reducing battery life, thus causing more of a differential (since they won't drain at the exact same level), thus reducing battery life more.

That is if the current limiters don't kick in and shut the device down (if it has them), or the extra current doesn't let the magic smoke out.

[JackANSI]

So if I bridged a DPDT it would technically be the same as a DPST?

Yes, or you could just use one side of it.

Makes sense, thanks.

so what about that diagram? If I have the right switch, is that how the wires should go?

That diagram is spot-on.

[Ron]

Yeah, Joe, the bottom diagram is what you would use. It switches the second battery in and out of the series circuit. The mod I was talking about would probably need major mods to the preamp also. I was just techin' out.

[Ron]

Joe, the bottom schematic in your diagram shows just that, switching from 9V to 18V at the flick of a switch. I'm not sure about the kind of pop you would get when switching it on the fly.

I found it odd that the 18V is wired that way. Apparently they are still using the same voltage divider as normal and just bumping the rails up with a higher input voltage. I wonder how much of a difference it would make to actually tie the wire connecting the series batteries to ground and use the remaining + and - terminals as +9V and -9V. As long as both batteries had the same charge, I would think that the op amp(s) in the preamp would perform at their best and there would be no resistors in a voltage divider to suck away any current or drop any voltage.

All batteries aren't created equal, thats why they don't do it that way. Even two batteries right next to each other in the assembly line will discharge at ever so slightly different rates. That leads to an offset (biased) voltage that would be usually carried to the output.

If it wasn't carried to the output the negative feedback on the opamp would carry that current around to cancel it, drawing more current to do it, thus reducing battery life, thus causing more of a differential (since they won't drain at the exact same level), thus reducing battery life more.

That is if the current limiters don't kick in and shut the device down (if it has them), or the extra current doesn't let the magic smoke out.

It would sound good for a little while, LOL

[metalchurch]

Cool thanks alot gentlemen, I appreciate it very much. I'm gonna try and have this wired tonight or tomorrow morning.

I hope that I don't get alot of noise between 9 and 18v. cause that's the main reason for the switch was to go back and forth betwen them, but it's not like it's a volume boost or anything so it's not a crucial element for anything at all.

Once again, Thank you

[JackANSI]

Cool thanks alot gentlemen, I appreciate it very much. I'm gonna try and have this wired tonight or tomorrow morning.

I hope that I don't get alot of noise between 9 and 18v. cause that's the main reason for the switch was to go back and forth betwen them, but it's not like it's a volume boost or anything so it's not a crucial element for anything at all.

Once again, Thank you

There might not be any as long as you flick the switch fast enough.

[metalchurch]

Jack, what difference did 18v offer for your bass? Could it be described like what mine were for guitar?

More headroom, brighter and more alive, also seemingly more sustain, and the strings are very sensitive to the touch now, ie. scratchy noises from the E/A/D strings.

[JackANSI]

It "evened" things out for me. Made the low strings clearer, made the high strings beefer. Makes getting it sounding good way easier.

But I guess I can sum it up like saying that it sounds like a thin film of plastic wrap was taken off the tone...

[metalchurch]

It "evened" things out for me. Made the low strings clearer, made the high strings beefer. Makes getting it sounding good way easier.

But I guess I can sum it up like saying that it sounds like a thin film of plastic wrap was taken off the tone...

I know exactly what you are saying. That's why I said it feels more responsive and alive.
I associate the compressed feel with a muffled type of tone, and the extra 9v of power helps to combat the nature of the active system.

If I can get this 9-18v switch going good, then I'd be set.
I have 1 hum and 1 volume in all of my guitars,and lately I've been craving more variety, and this mod filled the gap nicely.

[Charltor]

It "evened" things out for me. Made the low strings clearer, made the high strings beefer. Makes getting it sounding good way easier.

But I guess I can sum it up like saying that it sounds like a thin film of plastic wrap was taken off the tone...

I know exactly what you are saying. That's why I said it feels more responsive and alive.
I associate the compressed feel with a muffled type of tone, and the extra 9v of power helps to combat the nature of the active system.

I'd definitely like to try this mod on my 7 string and see how it clears up the EMG 707's. The one problem is where to store the extra battery on a string thru w/o modifying the battery compartment??? Any ideas Joe? The control switch cavity maybe big enough, but it might cause unwanted noise storing the battery in there?