K&K: 1 meg resistor mod

[35' Sunburst]

Then again Radio shack has the 1/8 watt 1M ohm in bulk (500) for sale on line:

http://www.radioshack.com/sm-1-8-wat...i-2994585.html

[guitaniac]

Originally Posted by Seagull Lover

I currently have a standard sized K&K in my Seagull. I have been having a bear of a time taming the bass and mids. When I cut the bass and mids to an acceptable level with my EQ pedal, it seems like I was missing something in the sound. I was thinking of switching to the K&K mini but I thought I would give the 1 meg resistor mod, that I read about in a recent thread, a try. I went to Radio Shack and spent $1 on a pack of 5 resistors, soldiered it into the plug of one of my instrument cords, and voila, I get a nice flat EQ. I don't think I even need my EQ pedal anymore; whatever EQing I need can probably be handled by the PA mixer. Right now I am just going straight into a passive DI box and it sounds pretty darn good. It's amazing what a little 20 cent resistor can do. Does anyone do this mod on the minis or is this something only done on the standard sized K&K's?

If your EQ pedal happened to be a Boss GE-7, you were already looking into a 1Mohm input impedance. Your mod would have reduced the input impedance to 500Kohms when running to the GE-7. I believe that the comparable MXR EQ pedal also has an input impedance of 1Mohm.

A lot of DI boxes have an input impedance of 1Mohm also, so your resultant input impedance (with the mod) would be 500Kohms in that event as well.

If you ran the K&K Pure Western directly to a PA mixer, you may be running to an input impedance as low as 50Kohms. The 1Mohm resistor fix wouldn't make much difference in that event.

Gary

[Seagull Lover]

Originally Posted by guitaniac

If your EQ pedal happened to be a Boss GE-7, you were already looking into a 1Mohm input impedance. Your mod would have reduced the input impedance to 500Kohms when running to the GE-7. I believe that the comparable MXR EQ pedal also has an input impedance of 1Mohm.

A lot of DI boxes have an input impedance of 1Mohm also, so your resultant input impedance (with the mod) would be 500Kohms in that event as well.

If you ran the K&K Pure Western directly to a PA mixer, you may be running to an input impedance as low as 50Kohms. The 1Mohm resistor fix wouldn't make much difference in that event.

Gary

I was thinking about that today. My EQ pedal is a GE-7 clone. I believe the input is 1M and the output is 1M impedance. My setup definitely sounded better when I plugged directly into my passive DI (ART Z-direct). I'm wondering what would happen if I installed the resistor at the output of the EQ pedal. I wish I understood the science of this better. How is it that my impedance directly to a PA mixer would be 50K ohms?

[sdelsolray]

Originally Posted by Seagull Lover

I was thinking about that today. My EQ pedal is a GE-7 clone. I believe the input is 1M and the output is 1M impedance. My setup definitely sounded better when I plugged directly into my passive DI (ART Z-direct). I'm wondering what would happen if I installed the resistor at the output of the EQ pedal. I wish I understood the science of this better. How is it that my impedance directly to a PA mixer would be 50K ohms?

Generally, you want the input impedance of the receiving unit to be at least 5 times the output impedance of the sending unit. I doubt the output impedance of your EQ pedal is 1 MegOhm - it's probably in the 50 to 600 Ohm range, at least it should be.

Gary is talking about the input impedance of some mixer inputs (line level inputs), which can be in the 50k Ohm +- range with some products. Microphone inputs on mixers may be in the 1,500 to 3k Ohm range.

[guitaniac]

Seagull Lover,

The GE-7's output impedance is 1Kohm. If your pedal is similar, nothing much would happen if you put a 1Mohm resistor across the output.

I can tell you from experience that the K&K mini-Pure SBT works pretty well with a GE-7. Perhaps your "clone" EQ pedal isn't much of a clone when it comes to quality and effectiveness.

Gary

[BuleriaChk]

I notice that the amps and effects I use now (the LR Baggs A-Ref, the GT-10 and the ME20 all have input impedances of 1 M Ohm, and the effect is immediately obvious, with plenty of signal.

The Boss GS-10 had the following specs.

Nominal Input Level
GUITAR/BASS INPUT: -10 dBu
MIC INPUT: -40 dBu (BALANCE)

Input Impedance
GUITAR/BASS INPUT: 1 MΩ
MIC INPUT: 2.2 kΩ

I found that I had to use the mic input for the PUTW; although it was a very low impedance, it was much more sensitive than the guitar input - there was not enough signal into the Guitar Input, even though it had an impedance of 1 M.....

I'll be trying out an RP500 within the next couple of days, which has an input impedance of 500K... it will be interesting to see what happens.....

But the 1 M resistor certainly revolutionized my sound, and I'll be paying a LOT more attention to input specs from here on out.....

Originally Posted by guitaniac

Seagull Lover,

The GE-7's output impedance is 1Kohm. If your pedal is similar, nothing much would happen if you put a 1Mohm resistor across the output.

I can tell you from experience that the K&K mini-Pure SBT works pretty well with a GE-7. Perhaps your "clone" EQ pedal is much of a clone when it comes to quality and effectiveness.

Gary

[sdelsolray]

Originally Posted by BuleriaChk

I notice that the amps and effects I use now (the LR Baggs A-Ref, the GT-10 and the ME20 all have input impedances of 1 M Ohm, and the effect is immediately obvious, with plenty of signal.

The Boss GS-10 had the following specs.

Nominal Input Level
GUITAR/BASS INPUT: -10 dBu
MIC INPUT: -40 dBu (BALANCE)

Input Impedance
GUITAR/BASS INPUT: 1 MΩ
MIC INPUT: 2.2 kΩ

I found that I had to use the mic input for the PUTW; although it was a very low impedance, it was much more sensitive than the guitar input - there was not enough signal into the Guitar Input, even though it had an impedance of 1 M.....

I'll be trying out an RP500 within the next couple of days, which has an input impedance of 500K... it will be interesting to see what happens.....

But the 1 M resistor certainly revolutionized my sound, and I'll be paying a LOT more attention to input specs from here on out.....

Appears as if you needed to load your PUTW pickup more than usual, perhaps due to the resonance of your instrument, placement of pickups, etc. In nearly all installations, PUTW film SBTs work best with 10 MegOhm input impedances.

[BuleriaChk]

Uh, what kind of equipment has 10 M input impedance? Maybe the PUTW Power plugs, but I don't want to use those.

The digitech stuff is even lower, often much lower (e.g. 600K, even 375K). (This probably is to reduce noise in long cable runs....)

Originally Posted by sdelsolray

Appears as if you needed to load your PUTW pickup more than usual, perhaps due to the resonance of your instrument, placement of pickups, etc. In nearly all installations, PUTW film SBTs work best with 10 MegOhm input impedances.

[6StringSamurai]

As far as I know, putting a resistor across the output of something should only affect the input impedance of the next device.

[guitaniac]

Well, if the output impedance of the GE-7 is 1Kohm, and the input impedance to the next device needs to be 5 or 10 times that for proper performance, putting a 1Mohm resistor across it won't make much difference, whether the input impedance of the next device is 20Kohms (like the PreSonus EQ3B), 10Mohms (like the PADI) or anything in between. The resultant input impedance of the next device will still be well over 10X1Kohm, in any case.

Gary

[sdelsolray]

Originally Posted by guitaniac

Well, if the output impedance of the GE-7 is 1Kohm, and the input impedance to the next device needs to be 5 or 10 times that for proper performance, putting a 1Mohm resistor across it won't make much difference, whether the input impedance of the next device is 20Kohms (like the PreSonus EQ3B), 10Mohms (like the PADI) or anything in between. The resultant input impedance of the next device will still be well over 10X1Kohm, in any case.

Gary

Yep, that's how things are designed to work these days.

[sdelsolray]

Originally Posted by BuleriaChk

Uh, what kind of equipment has 10 M input impedance? Maybe the PUTW Power plugs, but I don't want to use those.

The digitech stuff is even lower, often much lower (e.g. 600K, even 375K). (This probably is to reduce noise in long cable runs....)

The PUTW film pickups are designed to work with 10 MegOhm input impedances.

There are several products with 10 MegOhm input impedances for acoustic piezo pickups. Although there's no standard, it is the most common.

[BuleriaChk]

That is the point; with the 1 Meg modification, I can go into anything (so far)..... (GT-10, Me-20, VM3100Pro (for software modeling), Voxes....

Originally Posted by sdelsolray

The PUTW film pickups are designed to work with 10 MegOhm input impedances.

There are several products with 10 MegOhm input impedances for acoustic piezo pickups. Although there's no standard, it is the most common.

[Seagull Lover]

Originally Posted by BuleriaChk

I'll be trying out an RP500 within the next couple of days, which has an input impedance of 500K... it will be interesting to see what happens.....

I don't really like playing my acoustic through my RP250 (also 550k) but the sound is definitely better with the resistor mod. I notice the most difference when playing through the RP, the next most when playing through my keyboard amp and the least difference playing through my church's sound system.

Originally Posted by sdelsolray

Generally, you want the input impedance of the receiving unit to be at least 5 times the output impedance of the sending unit. I doubt the output impedance of your EQ pedal is 1 MegOhm - it's probably in the 50 to 600 Ohm range, at least it should be. Gary is talking about the input impedance of some mixer inputs (line level inputs), which can be in the 50k Ohm +- range with some products. Microphone inputs on mixers may be in the 1,500 to 3k Ohm range.

I have heard that the input impedance needing to be 10x higher than the source. I think this impedance bridging rule only applies to instrument and microphone sources and not to line sources. The output of my GLX EQ pedal is exactly the same as the Boss GE-7, which is 1 M ohm. The input of my passive DI is 50K. Sounds like I need a line level going into the DI so perhaps I might need a different DI.

On the other hand, following the impedance bridging rule, the 10M ohm input of most acoustic preamps should be perfect for the 1M ohm K&K pickup but it doesn't work. The impedance bridging rule seems to only be about signal strength; I can't find out anything about how it affects the EQ of a pickup. No wonder a lot of people just like to use the K&K XLR preamp/DI. The problem is I'm a cheapskate and I always have to do things the hard way.

When going to my keyboard amp, the sound is definitely better with the resistor mod at the output of the EQ pedal. The EQ now serves to improve the sound rather than putting a blanket over it.

I sure wish this forum allowed us to upload soundclips (I know the vbulletin software has that capability but it must not be enabled). I would love to upload some comparisons.

Here's another picture of the mod. Hopefully the link on this one will work okay.

[hann]

so this would be wrong huh...



how differently would it sound if i modded it this way compared to the link above? is it totally useless? I've no clue about these things and i was assuming electronic shop guys would've known to solder it across instead of in series... yikes.