Inductor confusion?

evhudsons

I spoke with partsconnexion to get the inductors for my crs+. I gave them the Solen part number, my credit card etc prior to that I had emailed inquiring about the inductors. Chris just responded to my email about the Solen but with a different description or type. Have you heard of this kind? Everett...



.my apologies for overlooking your e-mail....it got mis-filed.
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The SOLEN Hepta-litz is $*97.43 retail, less 10% discount....this is for the Hepta-litz version...highly recommended....let us know.
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From: Key West Gallery [mailto:kelliealpert@comcast.net]
Sent: Saturday, October 08, 2011 8:43 PM
To: info@partsconneXion.com
Subject: Inductors for Polk Audio SDA CRS+

Hello,*

I was wondering if I can order the Solen*16mH 14awg inductor (two of them) for my Polk Audio CRS+ speakers. I learned about you from the forum. I read that it is a special order item.*

My email is : evhudsons@aol.com

Thank you!

Everett

DarqueKnight

Solen's Hepta-Litz inductors are the same as the Standard inductors except that the Hepta-Litz versions have seven strand conductors instead of solid core conductors. The advantage of the Hepta-Litz design is that it offers less signal loss due to proximity effect and skin effect.

The disadvantages of the Hepta-Litz inductors are that they have in the range of 40% to 50% higher DC resistance than Solen's corresponding solid core inductors. They also cost $20-$25 more.

At higher frequencies, the lower loss Hepta-Litz design is preferable because high frequency signals contain less energy and are more affected by noise and losses (proximity effect and skin effect) in the inductor wire. Low frequency signals contain much higher energy and are not as affected by such losses. Additionally, the significantly higher DCR of the Hepta-Litz inductor will diminish bass performance compared to the corresponding solid inductor.

It is for these reasons that I chose Solen's solid core inductors rather than the Hepta-Litz versions for the low frequency sections of my SDA crossovers.

Consider that the goal of the inductor modification is to lower DC resistance in the SDA circuit.

dorokusai

I believe Chris is thinking more of an electronics application, than a speaker application. I'd ask Jeff @ Sonicraft or the North Creek folks in regards to speakers before Chris @ Parts Connexion and I'm a huge fan of his work.

evhudsons

Good advice. I'll check to make sure my phone order did or did not go through. Darknight was a fan of Solen but did say good things about northcreek. He just liked Solen better. Is jeff just soniccraft? Oh, and thanks for the quick answer!

dorokusai

I'm not saying don't buy them or follow his advice, just that I'm not sure if he fully knows what we're doing over here as opposed to Jeff....know what I mean? Jeff has been working with Polkies since F1Nut and I contacted him years ago.

DK is a fan of Solen for inductors, unless I'm mistaken and I agree since they are more cost effective with as much benefit as the North Creek alternative. I used NC in the past for other things but would go with the suggestion of Solen inductors from this point on unless cost is no object. He's done a lot of legwork on the subject and the logic is sound, regardless of the also excellent data.

I'm dreading some upcoming work on a couple xovers for Polkies, only because it's going to be seriously involved and time consuming. Xover work is easy in theory but can be a stressful proposition for the one doing the work.

Jeff = Sonicraft. There's another dude that works for him, that is also very helpful but I can't recall his name.

Face

dorokusai wrote: »

Jeff = Sonicraft. There's another dude that works for him, that is also very helpful but I can't recall his name.

Elliot?

dorokusai

Yeah, that's him. Thanks Mike.

thejck

Thanks for starting this thread. I was about ready to push the button on Hepta-litz..

Going to have Chris re-quote me for the standard instead. Save me some coin as well.
Thanks guys..

DarqueKnight

I am attaching the spec sheets for Solen's Hepta-Litz and Standard inductors. The first and last paragraphs on the first page of the Hepta-Litz spec sheets indicate that they are specifically suited for loudspeaker applications due to their low loss characteristics. This is probably why Chris highly recommends them.

However, a higher performing part may not be the best choice in every application. To reiterate, the Hepta-Litz's substantially higher DCR plus the minimal advantages of its low loss characteristics in the low frequency circuit led me to choose the Standard inductor.

evhudsons

Yes, thank you! Out of curiosity as some other threads mentioned erse inductors due to the cost and being similar though not a perfect match. Any thoughts on those? Unless there is compelling reason I think the Solen's work for me as they are triedand true. But the lower price does have some advantage as well. I'm adding a parasound 1500 amp to help with making sure I have enough power to handle the inductors.

DarqueKnight

evhudsons wrote: »

Out of curiosity as some other threads mentioned erse inductors due to the cost and being similar though not a perfect match. Any thoughts on those?

I recall a couple of of forum members who have used Erse's Super Q steel core inductors with good results. I like to run my SDA's with high power, high current amplifiers, therefore air core inductors are more appealing to me. Here is some advisement from Matthew Polk:

"The other concern is saturation of the inductor core. Air core inductors don't saturate. Given the cost of adequate ferrite or laminated core inductors at the time, plus the need for a higher DCR, the air core choice was obvious. So, when switching to a ferrite or laminated core inductor make sure it will handle at least 5 amps without saturation. That's equivalent to 100 watts of low frequency power through the SDA driver."

OldmanSRS

The Erse Super Q 16 ga coil is good for 500W per Erse. I can't hear its limits with a 400W/ch amp.

inspiredsports

. . . and while the purist in me wants the Solen 16 mH 10 gauge for my SDA 2B project, I'm settling for connecting 2 Each Erse Super Q 8 mH 14 gauge in series to get a 16 mH 14 gauge result with a 600W saturation rating.

While budget was not necessarily a constraint, the cash outlay delivered for a 4 Each Super Q's was a comfortable $128.74.

According to the tracking number they will be here in 4 hours and I hope to have the upgrade done within a few days

I don't think it will be possible to saturate these new 600W coils based upon the driver power handling capabilities/limits in an SDA 2B (or similar/identical architechure CRS/CRS+). I will report back as soon as I can.

evhudsons

Ill be using a Parasound HCA-1500A to run my crs+. It's rated at 205 wpc at 8 ohms, and the crs is 6 ohms. I want to be sure I get a good match. I just picked up a pioneer elite vsx90 that has preouts. It was used but I got that plus a power conditioner for $189 shipped. I know I need a real preamp eventually, put the preamp processors are a bit out of reach for this year. Any suggestions on the inductor for the current setup?

thejck

does it have a rating for 4 ohms on it?

drumminman

thejck wrote: »

does it have a rating for 4 ohms on it?

According to what I found it's 4 ohm stable: rated power 205 wpc 8ohms/ 315 wpc 4 ohms.

thejck

so you should be good then.

dorokusai

evhudsons wrote: »

Ill be using a Parasound HCA-1500A to run my crs+. It's rated at 205 wpc at 8 ohms, and the crs is 6 ohms. I want to be sure I get a good match. I just picked up a pioneer elite vsx90 that has preouts. It was used but I got that plus a power conditioner for $189 shipped. I know I need a real preamp eventually, put the preamp processors are a bit out of reach for this year. Any suggestions on the inductor for the current setup?

How about just listening before you start thinking of the next step?

WGDB

inspiredsports wrote: »

. . . and while the purist in me wants the Solen 16 mH 10 gauge for my SDA 2B project, I'm settling for connecting 2 Each Erse Super Q 8 mH 14 gauge in series to get a 16 mH 14 gauge result with a 600W saturation rating.

While budget was not necessarily a constraint, the cash outlay delivered for a 4 Each Super Q's was a comfortable $128.74.

According to the tracking number they will be here in 4 hours and I hope to have the upgrade done within a few days

I don't think it will be possible to saturate these new 600W coils based upon the driver power handling capabilities/limits in an SDA 2B (or similar/identical architechure CRS/CRS+). I will report back as soon as I can.

Inspired - Help me understand. Do inductors eventually fail? Are you changing your inductors because they are bad? Or, just for experimentation?

evhudsons

I am doing the change based on reading that it is a recommended tweak, and that there were positive changes noted besides just tighter bass. I think that is perfect advice about listening first Tony newer gear, once it gets here. It should arrive in a few days. I also want to hear what inspired reports. I noted in my original docs that came with my speaker that the amp watts recommended for the crs+ was up to about 200 wpc, which is what the parasound is at 8ohms. I'm assuming that it will handle more as an old advertisement said the crs+ was driven at 350 wpc without difficulty. I'm not sure what the inductor does actually. I also don't know about the saturation, or low dcr and what that means for me or how I operate the speakers, or the audible effects, etc.
I'm mainly just wanting to get the best sound, and this has turned into a fun hobby. Getting better gear will be extremely helpful I'm sure. Now I understand the preamp/processor and external amp idea.

evhudsons

I read on northcreek's site a bit about it, but it's still a bit technical. So im assuming it allows for better bass, but with enough resistance to not go too far into bass the signals that should go to the higher frequencies? And I thought aircore was the more desirable inductor, but I see you use the solid core? Sorry to ask seemingly dumb questions but I'm just starting to get a grasp on what all this means.

inspiredsports

WGDB wrote: »

Inspired - Help me understand. Do inductors eventually fail? Are you changing your inductors because they are bad? Or, just for experimentation?

I won't say impossible, but nearly impossible to hurt the big inductor in an SDA, but . . .

DK, Face and other have done a lot of research on their own, and conferred in depth with several of Polk's original SDA design engineers to learn what considerations (and compromises) went into choosing the original 1980's stock inductors. I guess a layman's way of putting it is that huge aural improvements in cancelling crosstalk with the SDA circuitry were made with a slight compromise to perfect bass response because of the average 1980's amplifier characteristics.

mH value for mH value, better inductors now exist from both a lower distortion and lower resistance standpoint.

Resistance is just that; high resistance coils (inductors) suck up and store huge amounts of power that could control/drive the low bass side of things in SDA cabinets. Higher resistance air core coils were used at the time because they absolutely do not saturate, and Polk NEEDED TO ADD DC Resistance to yield an impedance curve suitable to 1980's amps that were not comfortable driving into low 2-4ohm loads. THIS IS STILL A CONCERN IF YOU HAVE AN 8-ohm only capable amplifier.

When I say "purist" about not using air cores, air cores are still best in the sense tht they cannot saturate. I'm experimenting with the new technology Erse Super Q line that allows them to far exceed the point at which steel core inductors used to saturate, but they theoretically still can saturate.

At any rate, new lower DCR inductors will allow available amp current to flow through and control/improve deep bass. Because more current is allowed through, EVERYONE NEEDS TO UNDERSTAND THAT THEIR AMP WILL RUN HOTTER and must be capable of doing so.

evhudsons

Will it still do so at some expense of the SDA crosstalk elimination? I'm wondering because the crs as it snow puts out bass, but I have them on stands away from the wall and use a separate subwoofer for bass, filling in for what the crs is lacking. When I heard my friends 1cs that was entirely different. Tremendous bass once I armelled it tight. So for that I can see wanting to get more bass for the crs I'm just wanting better overall sound because it is deemed possible. Thanks for the fast and great explanation!

evhudsons

Also, i noted that tflf and others experienced more clarity and soundstage improvement, so that's more of what I was seeking although more bass would be nice.

inspiredsports

evhudsons wrote: »

Also, i noted that tflf and others experienced more clarity and soundstage improvement, so that's more of what I was seeking although more bass would be nice.

I'm not positive the clarity and soundstage improvements are related to the bass-improving lower DCR value, but it could be. I'm certain however that what I've read shows newer high-quality inductors to have lower distortion measurements than what was common in the 1980's.

evhudsons

I'm reading now the other cross pollinating thread regarding the erse super q, and unwinding. I'll keep posted on both your upgrade, and what erse says, and audiocreative's results.

I'm leaning still to the solen's, but the wallet is thin about now.

inspiredsports

evhudsons wrote: »

. . . will it still do so at some expense of the SDA crosstalk elimination? . . .

I missed this question this morning.

Better inductors will not compromise SDA crosstalk elimination. Lower distortion will enhance the quality of the signal in the SDA frequency range, and lower DCR (amp being capable) will enhance bass response. It's a win/win scenario.

Last, I'm convinced the 10awg Solens are the no compromise solution. I'm just not yet convinced the Erse's compromise (core can saturate at some point) will ever come into play within the operating parameters of 2B's/CRS's.

evhudsons

I would have to go with the 14 gauge for the crs. With all the inductor debates, I might just go with the solen 14 gauge, but that would be air core or solid core as a better choice?