AudioCircle

Audio/Video Gear and Systems => Owner's Circles => VMPS Speakers => Topic started by: revg1952 on 13 Nov 2017, 01:43 am

Title: rm1 xover
Post by: revg1952 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
(http://www.audiocircle.com/image.php?id=171260)

Title: Re: rm1 xover
Post by: PMAT 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.

Title: Re: rm1 xover
Post by: revg1952 on 13 Nov 2017, 04:30 pm

True my friend,true.
Revg

Title: Re: rm1 xover
Post by: Evoke on 13 Nov 2017, 04:44 pm

Quote from: revg1952 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
(http://www.audiocircle.com/image.php?id=171260)

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

Title: Re: rm1 xover
Post by: revg1952 on 13 Nov 2017, 05:27 pm

That has crossed my mind, I wanted to do a quick and dirty initial measurement,
Thnx
RevG

Title: Re: rm1 xover
Post by: revg1952 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

Title: Re: rm1 xover
Post by: Stimpy 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?

Title: Re: rm1 xover
Post by: revg1952 on 18 Nov 2017, 11:33 pm

Stimpy;
thanks for that thought; You are the Man.
RevG

Title: Re: rm1 xover
Post by: Stimpy 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 (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?

Title: Re: rm1 xover
Post by: PMAT on 13 Dec 2017, 09:09 pm

Here is my version. can someone help with pic orientation?

(http://www.audiocircle.com/image.php?id=172695)

(http://www.audiocircle.com/image.php?id=172696)

(http://www.audiocircle.com/image.php?id=172697)

Title: Re: rm1 xover
Post by: PMAT on 13 Dec 2017, 09:12 pm

woofer mod

(http://www.audiocircle.com/image.php?id=172698)

(http://www.audiocircle.com/image.php?id=172699)

(http://www.audiocircle.com/image.php?id=172700)

Title: Re: rm1 xover
Post by: PMAT 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/

Title: Re: rm1 xover
Post by: revg1952 on 13 Dec 2017, 10:13 pm

PMAT; thanks for taking the time to share
RevG