Help Needed: Resistors for Monitor 7Bs

racingkaherva

Hey Guys,
Forgive me if this is covered somewhere, but I've searched high and low and found nothing.

I am looking to recap my Monitor 7B crossovers. I know most appear to be fans of the Mills resistors, but I've read that the Mundorfs MOX are more open on the top, which might be desirable since I'm going through an old Marantz 1060.

The problem is the Mundorf MOX resistors only come in 4.7, not 4.5. Will this be problematic, or is the difference negligible?

Thanks.

westmassguy

racingkaherva wrote: »

Hey Guys,
Forgive me if this is covered somewhere, but I've searched high and low and found nothing.

I am looking to recap my Monitor 7B crossovers. I know most appear to be fans of the Mills resistors, but I've read that the Mundorfs MOX are more open on the top, which might be desirable since I'm going through an old Marantz 1060.

The problem is the Mundorf MOX resistors only come in 4.7, not 4.5. Will this be problematic, or is the difference negligible?

Thanks.

Wire a 2.7 and 2.0 in series, and you'll have your 4.7

Mystery

racingkaherva wrote: »

The problem is the Mundorf MOX resistors only come in 4.7, not 4.5. Will this be problematic, or is the difference negligible?
Thanks.

I think something is missing.
Monitor 7's either use 2.0 ohms or 2.7 ohms.
Where are you getting 4.7 ohms from?
May be I'm looking at wrong schematics.

racingkaherva

Thanks, guys. The 7Bs also have a 4.5 in there (in addition to the 2.7). I am wondering if I can use the Mundorf 4.7 in place of the 4.5.

Easy Runnin

Interesting, I recently picked up a pair of 7Bs and I have a 4.5 in one and a 4.0 in the other. I find it amazing there are so many variations in components.

F1nut

racingkaherva wrote: »

Thanks, guys. The 7Bs also have a 4.5 in there (in addition to the 2.7). I am wondering if I can use the Mundorf 4.7 in place of the 4.5.

You can although the extra .2 ohm value will attenuate the highs ever so slightly.

DON73

If I were doing this job for myself I wouldn't worry one whit about any audible difference in the Mills and Mundorf resistors. Use the Mills and be done with it.:cool:

Mr. Bubbles

I have never tried the Mundorfs but the Mills are great.

I looked over all three M7 schematics in the stickey and none show more than one resistor. Am I missing something? Where is the extra resistor in the circuit? I do not own the M7's but I like keep a library of all of the schematics for reference.

I would do as westmassguy recomended previously; a 2 and 2.5 in series will give you 4.5. Basically any combination in series that adds up to the desired value. larger values can be used in parrallel but can be harder to calculate unless they were both 9's. Either way if you are unfamiliar with calculating series and parrallel circuits there are calculators on the web that will do it for you.

Mystery

Mr. Bubbles wrote: »

I looked over all three M7 schematics in the stickey and none show more than one resistor. Am I missing something? Where is the extra resistor in the circuit? ...

That's what I thought as schematics don't mention it but they do have that 4.5 ohm resistor.
Here is a picture: http://www.polkaudio.com/forums/attachment.php?attachmentid=29493&stc=1&d=1196305628

Mr. Bubbles

all of the schematics show a protection device (polyswitch?, Fuse?) but I don't see either of those on that crossover. Maybe the extra resistor replaces that, though the values don't seem right for that. Maybe not. If anyone knows how both of the resistors are placed in the circuit maybe they can chime in and advise.

F1nut

Maybe the extra resistor replaces that

Definitely not.

racingkaherva

Thanks for the input, everyone. Much appreciated.

racingkaherva

I went with the Mills resistors and they sound pretty nice to me- not nearly as clouded as some have suggested.