Crossover values for unlisted switch combinations

[stratocaster]

When I was using the Manley Snappers with my 2WQs, I had chosen a value of 100K on the M5's that seemed to sound the best. This was despite the fact that the Manley's  have a 475K input impedance. After I got my Quatro's I never changed the value since I assumed that what worked for 2WQ would work for the Quatro's. However, recently I came across a thread where @Richard Vandersteen emphasized that the M5's have to be set on the ball with the Quatro's using the voltmeter and getting a .707 reading for track 30... This thread was enough for me to set on an expedition to fix the setting. It turned out that none of the listed combinations worked for me and I wasn't able to get to the .707 reading until I came across one post where Richard mentioned using switches 3,4,5. Well, that seemed to hit the mark with a precise .7 reading on the voltmeter.

I wonder how many folks out there are using switch combinations that aren't on the cover and what's the formula to determine the crossover value that corresponds to the switch combination. Not that knowing this value makes any difference as long as we remember the switches that need to be turned on...Nevertheless, this information is highly valuable for the anal retentive folks out there.😀

[Richard Vandersteen]

Nobody should be using the M5-HP(B) without using the voltmeter/test tracks as this is not ANAL but following instructions.  This is very important for reliability of the mid-bass driver on the Quatro, 5 Series, KENTO and SEVEN as they are very expensive!  If the setup is not close to .707v the mid-bass driver maybe subject to excessive excursion and power.  It is important for sonics also but then one suffers their own folly.  All the switches except 1,2.9.10 should be tried looking for .707v if one of the calibrated options is unsuccessful.  Why is this?  Many manufactures quote their input impedance incorrectly, I don't know why.  RV

[stratocaster]

@Richard Vandersteen does the input impedance of an amplifier change/degrade over a period of time? Considering the amps are at least 10 years old, I wonder if the measurement for an accurate reading should be performed periodically? Especially if there's a risk to the drivers.

Edited May 21 by stratocaster