Pad/DI on mic pre question

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Actually, a pad ( series resistance ) would be more economical and should not add any appreciable noise.

SvenArne


Thanks! But can I buy a 1/4 TS jack-jack adaptor with a resistor in the middle? Or how do you figure I would incorporate a pad into my setup? Mod my MICO by soldering in a pad at the DI input?

Sven

The input on that thing is only 500k so adding another 500k would get it to 1meg like many good guitar amps.  If you are handy you would make a cable with a 500k resistor built in. 

Or you might try one of these..

http://www.bhphotovideo.c...Box_Guitar_Pickup.html

You can simply put a "Pad" inline before you get to the pre-amp... they make them XLR M to XLR F and can reduce signal from 5db to over 60db:

Like this one
http://www.amazon.com/M-A...Inverter/dp/B001RI4YNS

SvenArne


Huh, so I guess Hi-Z has kind of a wide definition or what?

So how much gain reduction would an extra 500 kOhms give me?

(Look, if I accidentally sound like I know any more about electronics than the average housewife, I'm sorry)

Sven

I think it would be enough to keep it from distorting. You will have to use more preamp gain but if you are overdriving it now you will still have plenty available.  It will also reduce the load on your pickups and give you better tone and sustain.  If you're not handy with a soldering iron you might just buy one to make it easy.

Also consider that the potentiometer on your instrument IS a pad... I assume you want to leave it open for some good reason. Maybe you like the tone... your pickup and it's potentiometer and tone stack have a sweet spots etc. 

Thanks for the input! I like to record with the pots wide open only because it makes it easier to reproduce the exact same tone, should I return to the same project to add/improve on the same track.

I think the problem isn't the input impedance in itself, but rather the high amount of input gain (+18 dB at minimum). So a mod/cable/pad box would present different conditions depending on what guitar/bass/pickups I'm using, am I right? Would a passive Radial DI box give me a reproducible signal as well as having access to the -20 dB input pad?

Sven

DI is an option.
If you want to take the attenuator way, without altering the tone in any way, use this circuit with 2 resistors in the preamp side of the cable:

in ----- 910k -----!--------------- out (to preamp in)
                         !
                       100k
                         !
                         !
gnd ------------------------------- gnd     

If you can solder this is pretty easy to do inside the connector itself if you use 1/8w resistors.
The values shown are for 20dB attenuation and 1m impedance. Use 860k and 200k of 10dB.
You can also use a 500k or 1M log pot for variable attenuation. It won't colour the sound as long as it is in the preamp side.
If you put it in the gitar side, it will work exactly as the guitar volume pot, that will change also tone due to the combination of high impedance inductive source with capacitance in the cable. This does not happen with active guitars, though, these are low impedance sources and tone is not affected by vol pot.
This is infinitely cheaper than a DI box (costs just some cents), and also will give better performance. If you can't solder, you may be able to find some1 that does it for you.

In most cases instrument inputs in mic preamps are not affected by PAD. Not even in transformer ones as someone suggested (transformers are a big no for hi-z inputs). But in most cases the variable gain cover much lower gains, i would not like a preamp with a minimum gain of 18dB, that's a pretty poor range that severely limits its versatility. I always hated yamaha preamps for that reason, the min gain is 14 dB. Typical good modern preamps cover 0 dB gain and even some negative gain, making the pad unnecessary in most cases.