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Discussion in 'Pickups & Electronics [BG]' started by Horokito, Mar 9, 2005.
Does anyone know if the Nordstrand MM Pickup has enough output to be run passive?
It does. In fact I might as well just take my preamp out and sell it for as much as I use it. It sounds great passive.
To put the volume thing in perspective: my preamp is a Bartolini NTMB-918F, and when I first put the pickup in it was wired for 9v operation. Pulling the active/passive knob yielded no noticable volume difference. I've since set it up for 18v and there is a difference, but not as much as active vs passive on some other basses I've played.
The Nord output is ample. I'd guess 10K anyway, the Nord site didn't say that I could tell and I didn't measure it when I had one. In general, pup output is not an issue unless you have marginal amp output to get the job done. You just turn up the amp to compensate. All the MM's I've had had good output, the Barts were noticeable less but even they were good for passive. Most HB's have better than average output.
Also, I haven't been able tell a difference in tone of any significance if the amp output is boosted in active by-pass mode to the level of onboard preamp output. Variations in volume can make perception of tone very deceiving.
Most active/passive switches in reality are not active/passive switches but active by-pass switches, one leg of the preamp is still tied into the preamp circuitry. If you pull the battery and play in the passive mode and get no sound - it's an active by-pass. From what I recall (I don't use preamps anymore), I couldn't tell any difference between active and active by-pass but there was a significant difference in tone with a true active/passive switch.
Thats interesting info luknfur as i'm intending to fit a NORD MM with an OBP 3 and also wanted a proper Active / Passive.
Is it the switch type that matters or how the switch is wired up, that will determine whether its just a bypass, or proper passive ?
I think Carey would know.
The MM4.2 is plenty hot to run in passive mode. I have a 4.4(which isn't on my site yet) in my Sterling running passive through a 3 way (single front/parallel/single rear) and it works great.
These pickups don't have a high dc resistance. It's about 3.7k ohms per coil for the 4.2. Run in series it's about as much as a J pickup, but in parallel it's substantially less.
There is a common misconception about dc resistance and that it somehow equates to output. For a coil of the same size and structure it is true that more wire and higher resistance is coincedent with more output. But, for pickups of different design with different magnet sizes and coil sizes and wire sizes it not a good idea to estimate output based on resistance. This is especially the case with MM style pickups. The size of the magnet generates more output with less wire.
Anyway, if you want to do an active passive you will need a break before make switch. This will keep the switch from generating a feedback loop when you switch it which is what causes the POP. These are not terribly easy to find, although Mouser may have them. I actually disassemble and modify the push pull pots I get to allow for this kind of switching. Some day I'll put a photo tutorial of how to do this on my site...
I put an active/passive switch on my Nordstrand MM4.2 equipped Flea bass, and I honestly run it passive 90% of the time. Very useable tones.
To my knowledge, it would be more accurate to say the correlation between DC resistance and output is not a misconception at all but an accurate generalization. A wager that a randomly selected passive pup with higher DC resistance would have more output than another radomly selected passive pup with less DC resistance would pay off consistently. Pup design and components may throw a monkey wrench into the mix occassionally but to reference the relationship as a misconception seems as if it's some wive's tale. Or I am missing something here?
As mentioned in the previous post, I don't consider DC resistance a significant factor and the only time I've even checked it is for a suspected problem. But it can be a useful way to not only estimate output but, to a degree, tone without ever seeing or playing the pup.
It's also my understanding that a cap on the switch will eliminate the pop when switching. But I haven't ever done it. I know Dharmabass (and many others) will know about that.
Magus, I run straight to jacks so, unless required, I haven't messed with onboard wiring for about a year. I drew my conclusions and moved on. From what I recall, the active-bypass worked like a light switch, it just broke the incoming lead to the preamp - leaving the return lead untouched. That's why if the battery was pulled there was nothing in passive mode, cause that effectively broke the complete curcuit. You have to accomplish the same thing with a switch. I don't remember what switchs I used and exactly how I did it. I know I had to stick another switch in it with what I had on hand. But you can accomplish the same thing with a single switch of a different type.
When I did it, I rigged a bass so I could get active, active by-pass, active/passive, and pups straight to the jack - and A/B'd them with the flip of a switch(s).
Guys more up on this stuff like Davidwilson, Dharmabass, etc. would know. I only mentioned it to create an awareness in case someone wanted to explore that option and draw their own conclusions. From what I've gathered, just as preamps tend to reduce noise in a circuit, they also tend to reduce tone. A true passive can make a difference in that you'll get more tone - and more noise. With some pups the difference is significance, others not. You don't know till you do it.
Thanks bud. All opinions count.