[GeorgeAb]

I am the original owner of a pair of RM-30 speaker from approximately 2005.  I believe they are RM-30M, as they are four way with 10” side firing active speaker.    I have the standard capacitors and intend to upgrade.

Does anyone know the nominal value of the capacitors?   From what I am seeing I have one capacitor and two in parallel.   My capacitor meter only goes to 20uF and it appears the large one is just at 20uF and the two parallel are larger than 20uF.  I understand that Brian selected capacitors dependent on choke value to dial in crossover frequency; however, the nominal value is likely known.   Before I buy a better capacitance meter and reverse engineer the capacitor values, I thought I would throw it out to the VMPS community if anyone knows the values.   Thanks in advance.

[ZAKski288]

Hello GeorgeAb, you may consider upgrading to Series II RM-30. Here are a couple links. Good Luck Ken


https://www.audiocircle.com/index.php?topic=99305.0

https://www.audiocircle.com/index.php?topic=99304.0

[GeorgeAb]

Yes, Ken; makes a lot of sense.   The more I study the series II change the more it makes sense.   Those two 6.5” PR have to be working pretty hard against both the 10” active and two 6.5” active speakers.  Better balance with a 10” PR working against two 6.5” actives.       

With the added 10uF to the existing circuit for midrange crossover I can take the added 10uF capacitance into account when I purchase the new capacitors.   I have since ordered a proper capacitor meter so I can measure values.   When I determine values I will document here.

Based on my recent experience of upgrading capacitors in my preamp and headphone amplifier, I am kicking myself for not opting for the Auricaps when I ordered the speakers.   Fortunately they are not too hard to get to.   

[G E]

Yes, Ken; makes a lot of sense.   The more I study the series II change the more it makes sense.   Those two 6.5” PR have to be working pretty hard against both the 10” active and two 6.5” active speakers.  Better balance with a 10” PR working against two 6.5” actives.       

With the added 10uF to the existing circuit for midrange crossover I can take the added 10uF capacitance into account when I purchase the new capacitors.   I have since ordered a proper capacitor meter so I can measure values.   When I determine values I will document here.

Based on my recent experience of upgrading capacitors in my preamp and headphone amplifier, I am kicking myself for not opting for the Auricaps when I ordered the speakers.   Fortunately they are not too hard to get to.   

I got my RM30-m used and converted into them to series 2 including the 40 oz magnet mega woofer upgrade. They had Auricaps, silver wiring and the internal coating (sr71?) treatment from the factory.

The upgrade is well worth the effort. Much cleaner and deeper bass and well integrated lower midrange.

I can play these things late into the night

[GeorgeAb]

I got my RM30-m used and converted into them to series 2 including the 40 oz magnet mega woofer upgrade. They had Auricaps, silver wiring and the internal coating (sr71?) treatment from the factory.

The upgrade is well worth the effort. Much cleaner and deeper bass and well integrated lower midrange.

I can play these things late into the night

Concur, just finished this mod today.   I put this off as I was so satisfied with the low end of the RM30m.   However, after completing this and spending a couple hours of listening quite pleased with the modification.   Maintains natural low end as previous, but significant more impact at normal volume levels.   Look forward to receiving the 40oz mega woofer as they are ordered and five weeks out.   

On the capacitance values.   Word to the wise.   Disconnect the tweeter before measuring capacitance.   Shredded my tweeters.    Fortunately the Aurum Cantus G2Si tweeters are readily available.   

[GeorgeAb]

Since I asked what the capacitance value were, I wanted to follow up on values.   For midrange my values for the RM30M is 30.7uF for one speaker and 31.7uF for other.   For the series II it would be 10uF higher.   I used a 1% Mundorf Supreme for the Series II upgrade.   I assume the 1uF difference in values were based on coil value to get exact cutt-off frequency.   Brain mentioned test and calibrating to tight tolerance.   "We trim our crossovers to four decimal places"

Also quoting Brian from a FAQ on croossover tweaking as that is what I initially set off to do.   I am going to keep the standard capacitors for now.   Really content with the Series II upgrade and have always loved the midrange.   

"Crossover tweaking

Wholesale parts replacement in a speaker crossover is not generally a good idea, for several reasons.

First is the value tolerance of the parts. We trim our crossovers to four decimal places and use the same Bennic, Solen and Axon polypropylenes... Even 5% tolerances may swing the crossover hinge point beyond the designer's intended limits. Also, highly colored caps like the MIT's and Hovlands need to be compensated for elsewhere in the circuit. Not that they sound bad, just very distinctive, and you want to accentuate their good qualities while disguising the bad.

Upgrades often make things different, not better. Make sure you can tell the difference before embarking on circuit alterations."

Lastly, replaced my fried tweeters with the Aurum Cantus G2si so I am back to Series II baseline.