rm1 xover

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revg1952

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rm1 xover
« on: 13 Nov 2017, 01:43 am »
Thanks to Evoke and PMAT
 for your info and insights.
 The choke is stamped at 3.8mh my meter read 3.1 mh.
Gary


PMAT

Re: rm1 xover
« Reply #1 on: 13 Nov 2017, 03:35 am »
You can unwind a choke to get to a desired value. Not that it's the case here. What's the other speaker measure? My two were way off which I rectified. Can't remember the value. Everything must be checked on VMPS. QC was non existent. Sad but true.

revg1952

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Re: rm1 xover
« Reply #2 on: 13 Nov 2017, 04:30 pm »
True my friend,true.
Revg

Evoke

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    • EVOKE Planar Loudspeakers
Re: rm1 xover
« Reply #3 on: 13 Nov 2017, 04:44 pm »
Thanks to Evoke and PMAT
 for your info and insights.
 The choke is stamped at 3.8mh my meter read 3.1 mh.
Gary



Just a thought -


I'm looking at the XO and there doesn't appear to be a problem with the proximity of the components to each other. You might unsolder the choke and measure it again to make sure the circuit isn't impacting your measurement at all.


M

revg1952

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Re: rm1 xover
« Reply #4 on: 13 Nov 2017, 05:27 pm »
That has crossed my mind, I wanted to do a quick and dirty initial measurement,
Thnx
RevG

revg1952

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Re: rm1 xover
« Reply #5 on: 17 Nov 2017, 10:36 pm »
I was just about the take the plunge; and desolder the choke to get a more accurate reading. WHen I noticed the choke was was wired to the negative speaker terminal.In my experience and research on a 1st order slope(6db) the CHoke show being wired to the positive lead. THat is another reason I wanted to see a schematic for the RM1.
GAry

Stimpy

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Re: rm1 xover
« Reply #6 on: 18 Nov 2017, 11:10 pm »
I'm not a crossover genius, but I believe many of Brian's crossover designs were not only quasi first order, but also series crossovers, as opposed to the more common parallel crossovers.  So, maybe that makes a difference too, as to how the inductors are wired in circuit?

revg1952

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Re: rm1 xover
« Reply #7 on: 18 Nov 2017, 11:33 pm »
Stimpy;
thanks for that thought; You are the Man.
RevG

Stimpy

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Re: rm1 xover
« Reply #8 on: 18 Nov 2017, 11:52 pm »
Firstly, I mean no disrespect to Brian's memory or to VMPS owners, with this post.  I'm just trying to help the OP.

Next, as most here will remember, here's a link to a VMPS 626 mod, offered by Danny Richie. 

http://www.gr-research.com/vmps626r.htm

The 626 crossover should be very similar to the RM-1, and I was wondering if the 2 crossovers are similarly configured and wired?  I'm too color-blind to tell.  Sorry!  Maybe this will help with the wiring questions?

PMAT

Re: rm1 xover
« Reply #9 on: 13 Dec 2017, 09:09 pm »
Here is my version. can someone help with pic orientation?







PMAT

Re: rm1 xover
« Reply #10 on: 13 Dec 2017, 09:12 pm »
woofer mod







PMAT

Re: rm1 xover
« Reply #11 on: 13 Dec 2017, 09:16 pm »
The black strips on the passive radiator hole cover is really thick asphalt tape which dampens it. The port tube is covered with it as well. Here is a link to the woofers. They are cheeper now and great performers in the system. https://www.madisoundspeakerstore.com/approx-8-woofers/peerless-sls-830667-8-paper-cone-woofer/

revg1952

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Re: rm1 xover
« Reply #12 on: 13 Dec 2017, 10:13 pm »
PMAT; thanks for taking the time to share
RevG