Upgrade Low Frequency Inductors For the SDA SRS 1.2TL
DarqueKnight
Posts: 6,765
I achieved very good results when I replaced the stock 16 mH SDA inductor with a Solen "perfect lay" inductor of a larger gauge and much lower direct current resistance (DCR). Of course, replacing the SDA inductor is a Polk recommended modification. It has been advised, by Polk's engineering department, not to replace the smaller inductors in SDA crossovers unless the replacement has the same DCR and inductance value. Finding higher performing inductors with the same wire gauge, inductance and DCR has proven difficult.
When I replaced the 1 mH 18 gauge (DCR = 0.7 ohm) and 2 mH 20 gauge (DCR = 1.3 ohm) inductors in the low frequency section of my SDA SRS 1.2TL's with larger gauge, lower DCR inductors from North Creek Music Systems, the results were not positive (Link: Improvements To Modified SDA SRS 1.2TL Crossover). Based on my good results with the Solen replacement for the 16 mH SDA inductor, I looked to see if Solen offered comparable upgrade replacements for other inductors the 1.2TL's crossover. Solen does not make an inductor comparable to the 22 and 25 gauge bobbin wound inductors in the high frequency section. They do make comparable upgrade inductors for the 1 mH and 2 mH series inductors in the low frequency section.
Solen's 1 mH 18 gauge perfect lay inductor with a nominal inductance of 0.47 ohm and 2 mH 20 gauge perfect lay inductor with a nominal inductance of 1.05 ohm replaced the original scramble wound low frequency inductors in my SDA SRS 1.2TL's. I found Solen's perfect lay inductors to have better sonic performance and measurably better electrical noise performance than the North Creek inductors of comparable inductance and DCR. Solen also claims that the tighter perfect lay winding technique provides better mechanical vibration abatement.
I found that the DCR of Solen's 1 mH 18 gauge and 2 mH 20 gauge inductors measured higher than what is listed on their spec sheets. In fact, the DCR values were identical to the stock inductors. With the 20% sale discount and $18 shipping, the total came to $44.26 for the four inductors.
Figure 1. Solen's 1 mH and 2 mH inductors are actually smaller (and nicer looking) than the original
inductors and make Such Good Sound.
Figure 2. Solen low frequency inductors installed.
Conditioning Regimen
Figure 3. Solen recommends a break in period of 100 hours for their inductors. The Audiodharma Cable
Cooker accelerated the break in time with a high intensity conditioning signal.
The Solen inductors were first installed in the right speaker. Improvements were immediately evident. There was more visible cone movement in the right speaker and more tactile sensation coming through the listening seat's right arm rest. Even when my preamp was switched to mono mode, where each speaker is receiving the same signal, there was still more tactile sensation on the right side.
From the listening position, it sounded like the right side was a little clearer. The increase in clarity and detail on the right side was more evident when I took turns standing directly in front of each speaker while listening in mono mode. When listening to Dave Brubeck's "Take Five", the drum kit was on the left side of the sound stage, but I felt the percussive attacks of the snare drum and kick drum more strongly through the right armrest and through floor vibrations through my right foot. Proper sonic balance was restored after Solen inductors were installed in the left speaker.
After the initial listening session, the inductors were connected in series and conditioned for 26 hours. There was a small improvement in clarity and detail after this conditioning session. The next listening session after an additional 22 hours revealed a big improvement in clarity, detail, bass articulation and tactile sensation. The next listening session was done at the 58 hour mark and slight overcooking was evident (blurred bass and diminished overall detail). The overcooking artifacts disappeared after two hours of playback.
Listening Evaluation
The overall sound was apparently louder, which was indicative of a lowered noise floor, and images were thicker and heavier. The biggest change was in the sound of drums which took on a more "explosive" quality with more slam and tactile sensation. A couple of examples follow:
Dave Brubeck Quartet: "Time Out", 180 gram limited edition LP. On the "Take Five" track, the sound of the kick drum changed from a "WHOOMP" to a "POW". The subtle "twang" of the upright bass string tones was louder. The attack and impact of the snare drum solo was faster with more tactile sensation.
Phil Collins: "Face Value" LP. On the "In The Air Tonight" track, in addition the enhanced huge drum sound near the end of the track, there was a "second vocalist" behind and to the left of Phil Collins' voice. Near the end of the track and just before the main drum solo begins, is the addition of an electronically altered overdub of Collins' vocals. I had always heard this as an enhancement surrounding the main vocal. Now I hear it as a distinct, full bodied second voice.
The degree of sonic improvement was much higher when listening to vinyl records than with CD's and SACD's.
Response Measurements
The Solen inductors closely matched to original inductors in DCR and inductance value. As expected, the speaker's overall impedance response and DCR was unchanged by the modification. There were some improvements in frequency response. It must be noted that the pre-modification frequency response, harmonic distortion and bass decay plots were taken prior to the replacement of the Power Plant Premier AC regenerator with a PerfectWave P10 AC regenerator. Therefore, some of the improvements seen in the post-modification plots are attributable to the P10. This is particularly true with regard to harmonic distortion (my P10 review is here). Room response plots were taken with Dayton Audio's OmniMic system.
It is easier to see the differences in the plots if they are downloaded and viewed sequentially.
Figure 4. Pre-modification room response.
Figure 5. Post-modification room response.
The degree of flattening of response between 150 and 500 Hz was surprising.
The bass decay plots show how long it takes the sound to decay at each frequency. As shown on the legend to the right of the decay graph, the white area extends upward to indicate when the level drops no more than 5 decibels (dB). The light blue indicates when the level has dropped between 5dB and 10dB, etc. The ideal situation is not to have some bass notes lasting much longer than others. Significant differences in decay times can cause a decrease in bass definition.
Figure 6. Pre-modification bass decay.
Figure 7. Post-modification bass decay.
The color coded lines in the harmonic distortion plots represent the following:
Black - frequency response.
Dark blue - sum of 2nd-5th harmonics.
Red - 2nd harmonic.
Purple - 3rd harmonic.
Green - 4th harmonic.
Light blue - 5th harmonic.
Figure 8. Pre-modification harmonic distortion.
Figure 9. Post-modification harmonic distortion.
Installation Notes
The inductors came with long leads. I removed the cable ties, carefully straightened the leads, and then wound them around the inner and outer edges of the inductors. New cable ties were applied and the new windings were secured with hot glue. A "brace" of hot glue was applied in front of and behind the tangential points where the inductors joined the board.
Conclusion
Wire is not always just wire. The way wire is wound, the material(s) used to make the wire and the material(s) used to insulate the wire can have a significant effect on sound quality.
Figure 10. Twenty-two year old original low frequency inductors at their retirement party.
When I replaced the 1 mH 18 gauge (DCR = 0.7 ohm) and 2 mH 20 gauge (DCR = 1.3 ohm) inductors in the low frequency section of my SDA SRS 1.2TL's with larger gauge, lower DCR inductors from North Creek Music Systems, the results were not positive (Link: Improvements To Modified SDA SRS 1.2TL Crossover). Based on my good results with the Solen replacement for the 16 mH SDA inductor, I looked to see if Solen offered comparable upgrade replacements for other inductors the 1.2TL's crossover. Solen does not make an inductor comparable to the 22 and 25 gauge bobbin wound inductors in the high frequency section. They do make comparable upgrade inductors for the 1 mH and 2 mH series inductors in the low frequency section.
Solen's 1 mH 18 gauge perfect lay inductor with a nominal inductance of 0.47 ohm and 2 mH 20 gauge perfect lay inductor with a nominal inductance of 1.05 ohm replaced the original scramble wound low frequency inductors in my SDA SRS 1.2TL's. I found Solen's perfect lay inductors to have better sonic performance and measurably better electrical noise performance than the North Creek inductors of comparable inductance and DCR. Solen also claims that the tighter perfect lay winding technique provides better mechanical vibration abatement.
I found that the DCR of Solen's 1 mH 18 gauge and 2 mH 20 gauge inductors measured higher than what is listed on their spec sheets. In fact, the DCR values were identical to the stock inductors. With the 20% sale discount and $18 shipping, the total came to $44.26 for the four inductors.
Figure 1. Solen's 1 mH and 2 mH inductors are actually smaller (and nicer looking) than the original
inductors and make Such Good Sound.
Figure 2. Solen low frequency inductors installed.
Conditioning Regimen
Figure 3. Solen recommends a break in period of 100 hours for their inductors. The Audiodharma Cable
Cooker accelerated the break in time with a high intensity conditioning signal.
The Solen inductors were first installed in the right speaker. Improvements were immediately evident. There was more visible cone movement in the right speaker and more tactile sensation coming through the listening seat's right arm rest. Even when my preamp was switched to mono mode, where each speaker is receiving the same signal, there was still more tactile sensation on the right side.
From the listening position, it sounded like the right side was a little clearer. The increase in clarity and detail on the right side was more evident when I took turns standing directly in front of each speaker while listening in mono mode. When listening to Dave Brubeck's "Take Five", the drum kit was on the left side of the sound stage, but I felt the percussive attacks of the snare drum and kick drum more strongly through the right armrest and through floor vibrations through my right foot. Proper sonic balance was restored after Solen inductors were installed in the left speaker.
After the initial listening session, the inductors were connected in series and conditioned for 26 hours. There was a small improvement in clarity and detail after this conditioning session. The next listening session after an additional 22 hours revealed a big improvement in clarity, detail, bass articulation and tactile sensation. The next listening session was done at the 58 hour mark and slight overcooking was evident (blurred bass and diminished overall detail). The overcooking artifacts disappeared after two hours of playback.
Listening Evaluation
The overall sound was apparently louder, which was indicative of a lowered noise floor, and images were thicker and heavier. The biggest change was in the sound of drums which took on a more "explosive" quality with more slam and tactile sensation. A couple of examples follow:
Dave Brubeck Quartet: "Time Out", 180 gram limited edition LP. On the "Take Five" track, the sound of the kick drum changed from a "WHOOMP" to a "POW". The subtle "twang" of the upright bass string tones was louder. The attack and impact of the snare drum solo was faster with more tactile sensation.
Phil Collins: "Face Value" LP. On the "In The Air Tonight" track, in addition the enhanced huge drum sound near the end of the track, there was a "second vocalist" behind and to the left of Phil Collins' voice. Near the end of the track and just before the main drum solo begins, is the addition of an electronically altered overdub of Collins' vocals. I had always heard this as an enhancement surrounding the main vocal. Now I hear it as a distinct, full bodied second voice.
The degree of sonic improvement was much higher when listening to vinyl records than with CD's and SACD's.
Response Measurements
The Solen inductors closely matched to original inductors in DCR and inductance value. As expected, the speaker's overall impedance response and DCR was unchanged by the modification. There were some improvements in frequency response. It must be noted that the pre-modification frequency response, harmonic distortion and bass decay plots were taken prior to the replacement of the Power Plant Premier AC regenerator with a PerfectWave P10 AC regenerator. Therefore, some of the improvements seen in the post-modification plots are attributable to the P10. This is particularly true with regard to harmonic distortion (my P10 review is here). Room response plots were taken with Dayton Audio's OmniMic system.
It is easier to see the differences in the plots if they are downloaded and viewed sequentially.
Table 1
Figure 4. Pre-modification room response.
Figure 5. Post-modification room response.
The degree of flattening of response between 150 and 500 Hz was surprising.
The bass decay plots show how long it takes the sound to decay at each frequency. As shown on the legend to the right of the decay graph, the white area extends upward to indicate when the level drops no more than 5 decibels (dB). The light blue indicates when the level has dropped between 5dB and 10dB, etc. The ideal situation is not to have some bass notes lasting much longer than others. Significant differences in decay times can cause a decrease in bass definition.
Figure 6. Pre-modification bass decay.
Figure 7. Post-modification bass decay.
The color coded lines in the harmonic distortion plots represent the following:
Black - frequency response.
Dark blue - sum of 2nd-5th harmonics.
Red - 2nd harmonic.
Purple - 3rd harmonic.
Green - 4th harmonic.
Light blue - 5th harmonic.
Figure 8. Pre-modification harmonic distortion.
Figure 9. Post-modification harmonic distortion.
Installation Notes
The inductors came with long leads. I removed the cable ties, carefully straightened the leads, and then wound them around the inner and outer edges of the inductors. New cable ties were applied and the new windings were secured with hot glue. A "brace" of hot glue was applied in front of and behind the tangential points where the inductors joined the board.
Conclusion
Wire is not always just wire. The way wire is wound, the material(s) used to make the wire and the material(s) used to insulate the wire can have a significant effect on sound quality.
Figure 10. Twenty-two year old original low frequency inductors at their retirement party.
Proud and loyal citizen of the Digital Domain and Solid State Country!
Post edited by DarqueKnight on
Comments
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Very nice write up Raife. I admit that I have procrastinated to replace the stock 16 mH SDA inductor with a Solen "perfect lay" inductor. I need to get my lazy butt in motion.
One interesting observation that you made that I found to be so true. The degree of sonic improvement was much higher when listening to vinyl records than with CD's and SACD's. Additionally the weight, impact and clarity of the SDA lateral soundstage is much more profound with vinyl and R2R that had vinyl as a source. It is there with CDs, SACDs and FM broadcast music but SDAs really shine with vinyl. Digital is very good and has it's obvious advantages. Vinyl has "such good sound" but also has it's disadvantages.
I enjoy finding high quality classical and jazz vinyl at garage sales for next to nothing. I have found some 40 and 50 year old vinyl that was never opened. Incuding some RCA "shaded dog" labels.
Good fun this hobby!
Thanks again for your contributions.
Regards,Carl -
Stunning, Raife!
I thought I was nearly done, and now this :cool: I think Polk needs to start a owner tweak Hall of Fame, with you as the charter member.
Well done!"Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer -
I have had my eye on those for sometime wondering if it would be worth it just to try them out.
Ordered and shipped today!!!!
Thanks for helping spend my money Ray.. -
I was wondering what happened to your endeavors and was missing reading your posts on your trials and experiments with analyzable results. I'm glad to see you were busy! Now that I updated my large inductors I find I need to do the smaller ones too! Awesome!
I needed a next step, and thanks!
New Years resolution: careful and consistent listening.Polk Audio SDA CRS+ crossover 4.1TL by Trey/VR3 (Rings and custom stand by Larry)-Polk Audio SDA SRS2 crossovers by Trey/VR3Parasound HCA1500aYamaha rxa-3070 with musicast-Celestion SL6S presence,- sl9 surround backNHTsuper1's surroundMagnepan SMGParasound 1500pre- Sofia "Baby" tube amp - Monitor Audio Silver RX2 Marantz 2230/B&Kst140Technics 1200mk2 Gamertag: IslandBerserker I am but a infinitesimally small point meeting the line of infinity in the SDA universe -
Dam you Ray, Dam you all to hell.
Looks and sound like you found a perfect match.
I wonder if Solen would make custom inductors. Maybe I'll give them a call after the new year.“The two most important days in your life are the day you are born and the day you find out why.” ~ Mark Twain -
Tony, that'd be worth finding out. I have a feeling CP would clear them out if they did in fact make custom inductors!
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If you order enough, I'm sure they would.Dam you Ray, Dam you all to hell.
Looks and sound like you found a perfect match.
I wonder if Solen would make custom inductors. Maybe I'll give them a call after the new year."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche -
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I wonder if Solen would make custom inductors. Maybe I'll give them a call after the new year.audiocr381ve wrote: »Tony, that'd be worth finding out. I have a feeling CP would clear them out if they did in fact make custom inductors!If you order enough, I'm sure they would.audiocr381ve wrote: »Uh-oh. Group buy time?
I already asked Solen about a custom inductor order and they said no. I didn't ask about a large quantity order or if there was some technical reason why they didn't offer the inductors in smaller wire sizes (22-25 AWG).
There's probably a magic $$$number$$$ at which they could be persuaded to do this.Proud and loyal citizen of the Digital Domain and Solid State Country! -
Try Madisound."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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Looks and sound like you found a perfect match.
Finding inductors that meet the inductance and DCR requirements isn't that hard. Finding inductors that meet the inductance and DCR requirements AND that have better sonic performance is hard.
The easier thing might be to use higher performing, larger gauge inductors in the HF section, but make appropriate adjustments to the capacitors and resistors so that the frequency response isn't skewed. That would be a nice project for me to take on in the future...when I'm more dedicated to audio than I am now.:razz:Proud and loyal citizen of the Digital Domain and Solid State Country! -
DarqueKnight wrote: »Finding inductors that meet the inductance and DCR requirements isn't that hard. Finding inductors that meet the inductance and DCR requirements AND that have better sonic performance is hard.
The easier thing might be to use higher performing, larger gauge inductors in the HF section, but make appropriate adjustments to the capacitors and resistors so that the frequency response isn't skewed. That would be a nice project for me to take on in the future...when I'm more dedicated to audio than I am now.:razz:
I've heard THAT before -
Yep might have heard that before too. For what it's worth you can count me in for crs+ inductors if y'all do a group buy.
Happy New Year!Polk Audio SDA CRS+ crossover 4.1TL by Trey/VR3 (Rings and custom stand by Larry)-Polk Audio SDA SRS2 crossovers by Trey/VR3Parasound HCA1500aYamaha rxa-3070 with musicast-Celestion SL6S presence,- sl9 surround backNHTsuper1's surroundMagnepan SMGParasound 1500pre- Sofia "Baby" tube amp - Monitor Audio Silver RX2 Marantz 2230/B&Kst140Technics 1200mk2 Gamertag: IslandBerserker I am but a infinitesimally small point meeting the line of infinity in the SDA universe -
Ray are you still happy with the results from these inductors? I'm looking forward In getting them..
You guys know I'm in on a group buy if needed so just count me in.. -
I'd love to get a set for my 2.3TL's, but when I had a look they only had one that had the exact measurements as the stock ones. I know folks like Danny Ritchie and Sonicraft will unwind stock inductors to meet specs - but they don't carry Solens."Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
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Ray are you still happy with the results from these inductors?
Absolutely.drumminman wrote: »I know folks like Danny Ritchie and Sonicraft will unwind stock inductors to meet specs - but they don't carry Solens.
When unwinding inductors to a specific inductance, be careful that the DCR also meets the required value. Two inductors of with the same number of windings and same inductance value can have different DCR's if the copper formulations are very different. The required inductance and DCR should always be specified.Proud and loyal citizen of the Digital Domain and Solid State Country! -
How 'bout a given inductance and a lower DCR, then add a quality resistor of proper value in series to return the DCR to stock spec?DarqueKnight wrote: »The required inductance and DCR should always be specified. -
Love your stuff, DK, but could you:
- do us poor, color-blind folk a favor and lay off the red-green use in graphs?I followed Fig. 8 with reasonable ease, but Fig.9... not so much... We thank you in advance... :cool:)
- post a couple overlaid graphs, e.g., Fig's 4 & 5?Was thinking maybe 8 & 9 as well, but result would be too busy. Maybe just the Sum result?
I'll be back with some more serious questions later... :question: ...but I loved this...
Just no substitute for infinite sampling...The degree of sonic improvement was much higher when listening to vinyl records than with CD's and SACD's.More later,
Tour...
Vox Copuli
Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb
"Death doesn't come with a Uhaul." - Dennis Gardner
"It's easy to get lost in price vs performance vs ego vs illusion." - doro
"There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD -
DK just made me spend more money. I always get the feeling that whenever I come to this forum, I spend what little life savings I have left.Statistics show that 98% of us will die at some point in our lifetime.
The other 2% will work for WalMart. -
Both graphs were made using the same method and that's how the program spits them out, IIRC you can't change the colors for that graph.- do us poor, color-blind folk a favor and lay off the red-green use in graphs?I followed Fig. 8 with reasonable ease, but Fig.9... not so much... We thank you in advance... :cool:)"He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche -
...could you:
- do us poor, color-blind folk a favor and lay off the red-green use in graphs?I followed Fig. 8 with reasonable ease, but Fig.9... not so much... We thank you in advance... :cool:)
- post a couple overlaid graphs, e.g., Fig's 4 & 5?Was thinking maybe 8 & 9 as well, but result would be too busy. Maybe just the Sum result?Both graphs were made using the same method and that's how the program spits them out, IIRC you can't change the colors for that graph.
Face is correct. We are out of luck with regard to changing the color of the lines in the harmonic distortion plots. In addition to changing line colors, it would be nice to have the option of making lines in dashes, dots and other symbols for printing in black and white.
The line colors can be changed in the frequency response plots. Here is an overlay plot of the before and after room response:
...I'll be back with some more serious questions later... :question: ...but I loved this...DarqueKnight wrote: »The degree of sonic improvement was much higher when listening to vinyl records than with CD's and SACD's.
Just no substitute for infinite sampling...
Yeah, no matter how good sampling gets, sampling is still sampling and information is still being missed between samples and between the analog quantity and its digital approximation. I have found that as the resolution of my two channel system has improved, the sound quality difference between analog and digital becomes more apparent. However, I must add the qualifier that my analog source costs 2X the amount of my digital source.How 'bout a given inductance and a lower DCR, then add a quality resistor of proper value in series to return the DCR to stock spec?
Two things to consider when adding a resistor in series with an inductor in order to raise the inductor's DCR:
1. An inductor's DCR changes with temperature. It would be difficult to match a resistor's DCR temperature gradient to that of the associated inductor.
2. An inductor's Q (quality factor), which varies with frequency, is decreased by adding external resistance. He higher the Q factor, the greater the ability of the inductor to store energy. Decreasing Q can result in decreased woofer control, which equates to decreased bass weigh and decreased bass detail.PolkMaster1 wrote: »DK just made me spend more money. I always get the feeling that whenever I come to this forum, I spend what little life savings I have left.
There are worse things to be hooked on...and some of those things actually do make people deplete their life savings.
Proud and loyal citizen of the Digital Domain and Solid State Country! -
...could you:
- do us poor, color-blind folk a favor and lay off the red-green use in graphs?I followed Fig. 8 with reasonable ease, but Fig.9... not so much... We thank you in advance... :cool:)
- post a couple overlaid graphs, e.g., Fig's 4 & 5?Was thinking maybe 8 & 9 as well, but result would be too busy. Maybe just the Sum result?
Providing the individual results for the 2nd-5th harmonics provides some insight into increased sonic performance because odd order harmonics, particularly the 3rd, are usually the most sonically obnoxious.Proud and loyal citizen of the Digital Domain and Solid State Country! -
Does the inductor's temperature change much in actual use? I'm guessing it's fairly stable because there isn't much current going through it; along with a reasonable amount of air movement inside the cabinet. Of course, position of the inductor with regards to air movement can vary tremendously.DarqueKnight wrote: »Two things to consider when adding a resistor in series with an inductor in order to raise the inductor's DCR:
1. An inductor's DCR changes with temperature. It would be difficult to match a resistor's DCR temperature gradient to that of the associated inductor.
I accept that DCR changes the Q; but does adding a resistor to a low-DCR inductor result in a different Q than just sourcing an inductor with the same DCR as the (combined) low-DCR inductor + resistor set?DarqueKnight wrote: »2. An inductor's Q (quality factor), which varies with frequency, is decreased by adding external resistance. He higher the Q factor, the greater the ability of the inductor to store energy. Decreasing Q can result in decreased woofer control, which equates to decreased bass weigh and decreased bass detail. -
I accept that DCR changes the Q; but does adding a resistor to a low-DCR inductor result in a different Q than just sourcing an inductor with the same DCR as the (combined) low-DCR inductor + resistor set?
I've never measured this. I expect that, since the resistor and inductor have different electrical and mechanical properties, the resistor/inductor combination would have a different Q than an inductor with the same DCR. Another thing to consider is that, when Polk's engineering department offered advisement on changing inductors in their speaker crossovers, it was advised to choose an inductor whose inductance and DCR matches the original inductor rather just concentrating on matching inductance value and then using a resistor to match DCR.
I also expect that, since speaker modifiers go to great lengths to find upgrade inductors that match the original inductance and DCR, it is not just a simple matter of popping in a resistor to pump up the inductor's DCR.
Again, I don't have any practical experience with this. Perhaps some of the forum's speaker builders will chime in with some practical, hands-on experience. Just from looking at the equations for inductor Q, and the mathematical model for a real, non-ideal, resistor, attaching a resistor in series with an inductor to raise the inductor's DCR does not appear appealing.Proud and loyal citizen of the Digital Domain and Solid State Country! -
I have had my eye on those for sometime wondering if it would be worth it just to try them out.
Ordered and shipped today!!!!
Thanks for helping spend my money Ray..
me too.. i need to order these today. are they still on sale? -
I have been waiting for this I always wondered what I might be missing out on since my 1mH and 2mH inductors are not stock 1.2TL but 1.2 modded by Ben.
Now I can just take this to the next level.
Awesome work DK. I love you -
Dam you Ray, Dam you all to hell.
Looks and sound like you found a perfect match.
I wonder if Solen would make custom inductors. Maybe I'll give them a call after the new year.
I have tried and they dont seem too -
These the part numbers confirm please?
ITEM S202.0
S181.0 -
These the part numbers confirm please?
ITEM S202.0
S181.0
Those are the correct part numbers.
I am waiting on a reply from Solen regarding the discrepancy between the spec DCR values and the measured DCR values. The spec DCR for the 10 AWG 16 mH inductor was 0.56 ohm, but it measured 0.8 ohm.
I speculated that the spec DCR's for the 1.0 mH 18 AWG and 2.0 mH 20 AWG inductors would have a similar discrepancy and I was right:
The 1 mH spec DCR was 0.47 ohm and it measured 0.7 ohm, which was the same as the original 1 mH inductor.
The 2 mH spec DCR was 1.05 ohm and it measured 1.3 ohm, which was the same as the original 2 mH inductor.Proud and loyal citizen of the Digital Domain and Solid State Country! -
If u have seem my previous posts on here, I have been searching for these inductors to match what is on the schema for the 1.2TL. I had my eye on those 2 inductors but held off because the DCR was rated less so I am pleasantly surprised. I wonder if this was something specific to the ones you received or this is normal for all of them.
