Need wiring help...

mediumjim · 2010

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Offline mediumjim

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on: February 10, 2011, 06:25:23 PM
I recently bought a pair of University Medallion XII speakers that simply wonderful, but have one thing that needs to be upgraded, the simple on/off toggle switch for the presence.  What I want to do is replace it with a 100k audio taper pot to allow for controlled settings.   What is the best pot for the job and how do I wire it.   

Thanks,

Jim

Marantz Model 9's Bottlehead FP2 AH!Tjoeb 99
Dynaco ST-70 McIntosh MX-110 Rotel RCD1072
KEF 104/2 B&W ASW300 Subs
Dynaco A-150 University Medallion XII


Offline mediumjim

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Reply #1 on: February 11, 2011, 04:31:43 AM
Wow, I'm surprised that someone hasn't responded to a rather simple problem.   Would it be a simple hot lead to one of the lugs and grounding the cold lead to the pot?  Would 100K be the proper value and would linear be better or worse than audio taper?

Thanks,
Jim

Marantz Model 9's Bottlehead FP2 AH!Tjoeb 99
Dynaco ST-70 McIntosh MX-110 Rotel RCD1072
KEF 104/2 B&W ASW300 Subs
Dynaco A-150 University Medallion XII


Offline Paul Joppa

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Reply #2 on: February 11, 2011, 11:08:28 AM
It depends on the circuit. It may not be possible at all. It does seem very unlikely that a 100,000 ohm resistance would be useful in an 8 or 16 ohm crossover circuit.

Paul Joppa


Offline mediumjim

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Reply #3 on: February 11, 2011, 03:13:48 PM
Paul:

Thanks, I actually got them positioned where they sound truly wonderful.  I would have to think they were sleeping and woke up (today).  I was in a real good place listening to some Aaron Copeland and then Jean Luc Ponty/Stephane Grappeli.  I may have to get another pair to mate with my Marantz 9's and run them in triode.   

The system is a 1963 Dynaco ST-70, 1961 McIntosh MX-110, a 2009 Rotel RCD-1072 CD player and the circa 1960 University Sound Medallion XII's...this is one of the best sounding systems I've put together no matter the cost. 

My Marantz's are the VAC's from the mid 1980's with a modified Bottlehead Foreplay II, and a AH! Tjoeb 99 Tube CD Player...It sounds wonderful with a pair of KEF 104/2's, but I feel that it would do better with a pair of Vintage Speakers, say some nice Jensen's,  or another pair of University's.   

Suffice it to say, I'm blown away on how good they are.  Some times you take a chance and get rewarded!

Jim

Marantz Model 9's Bottlehead FP2 AH!Tjoeb 99
Dynaco ST-70 McIntosh MX-110 Rotel RCD1072
KEF 104/2 B&W ASW300 Subs
Dynaco A-150 University Medallion XII


Offline Grainger49

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Reply #4 on: February 14, 2011, 02:46:20 AM
I recently bought a pair of University Medallion XII speakers that simply wonderful, but have one thing that needs to be upgraded, the simple on/off toggle switch for the presence.  What I want to do is replace it with a 100k audio taper pot to allow for controlled settings.   What is the best pot for the job and how do I wire it.    

Thanks,

Jim

What PJ is saying is that most crossovers use fixed resistors (selected by the toggle switch mentioned in red above), as yours probably did, to attenuate sound from a given driver.  These resistors are most often from 1 to 30 ohms.  A 100,000 ohm pot would be way too much attenuation for any crossover I have seen.  Seeing as most drivers are 4 to 16 ohms 100,000 ohms in series would eliminate any sound coming from them.

I would expect a good 16 ohm L Pad wired as a variable resistor would do the job very well.  But you haven't mentioned the resistor values that the toggle switch controls.

I guess you found a position for working with this.
« Last Edit: February 14, 2011, 02:49:09 AM by Grainger49 »