2.3 TL Inductor upgrade?

dpowell

Looking for recommendations on the next upgrade. I've completed XOs with gimpod boards and sonicaps/mills, binding posts, dynamatted driver baskets, RDO tweeters, Larry's rings and 1000VA dreadnought. Looking now towards the inductors but after reading the SDA compendium and the vr3 sda upgrades site, I'm still not sure what exactly I would order. It also seems like some tweaking may be required to achieve correct inductor values. Did some searching on inductors in the forum and am not seeing a lot of info.

The other alternative I'm considering is an IC upgrade. Currently using signal cable analog II but also have some MIT terminator 3s in the mix. I'd like to standardize all the ICs.

If you had to pick one upgrade over the other, which one would you choose?

pitdogg2

@westmassguy gave me a list when i have time I'll try and find it. All should be tested as they can be a bit off as i found out.
Also @VR3 will be a go to as well.

pitdogg2

Do not believe parts express carries the correct inductors.
Jentzan and Erse direct.

F1nut

BartDaws wrote: »

IC's are awesome. I'm a noob so don't know which one. You do need that SONIC BARRIER at parts express so crank up the free shipping on the coils.

Were you dropped on your head as a baby or is your IQ naturally low?

dpowell

Any chance this thread can stay civil and focused on the question at hand?

pitdogg2

https://www.hificollective.co.uk/components/mills.html

2 x 000-0818 - .875mh 18awg

2 x 000-1489 - .4mh 22awg

2 x 000 - 1452 -.30mh 22awg

2 - 000 - 1480 - 1.8mh 20 awg

This is the only place I've found the .5 ohm vashay-mills 12 watt resistor so might want to get a few as well. Can't hurt to have some on hand.



http://www.erseaudio.com/Products/SuperQCoils16Gauge/ESQ55-16-18000

You'll need 2 ^^^^^^^


All of these will need to be tested and some unwound to meet spec's

Some of mine were quite a bit off and off course the Erse will need to be unwound to 16mh.

Hope this helps @dpowell

westmassguy

pitdogg2 wrote: »

https://www.hificollective.co.uk/components/mills.html

2 x 000-0818 - .875mh 18awg

2 x 000-1489 - .4mh 22awg

2 x 000 - 1452 -.30mh 22awg

2 - 000 - 1480 - 1.8mh 20 awg

This is the only place I've found the .5 ohm vashay-mills 12 watt resistor so might want to get a few as well. Can't hurt to have some on hand.



http://www.erseaudio.com/Products/SuperQCoils16Gauge/ESQ55-16-18000

You'll need 2 ^^^^^^^


All of these will need to be tested and some unwound to meet spec's

Some of mine were quite a bit off and off course the Erse will need to be unwound to 16mh.

Hope this helps @dpowell

Beat me to it Ivan. The 1.8 needs to be unwound. and would advise checking all of them.

dpowell

Thanks! I will take a look at those links.

bem

I’m the original owner of a pair of 2.3s (not TLs) that are 30 years old that have upgraded tweeters but no other mods. I plan on having the crossovers done by DHS and I am considering doing the inductors as well. My only concern is the whether my amp can handle the drop in impedance that is created with the new inductors. I’m using a Parasound A21 and I was wondering if anyone has done the inductor upgrade and is using a A21.

gmcman

westmassguy wrote: »

The 1.8 needs to be unwound. and would advise checking all of them.

Just curious, when unwinding the inductors, are you using a certain freq when testing with an LCR meter? If so, what do you generally use?

Thanks.

VR3

FWIW -

https://www.hificollective.co.uk/catalog/000-0819-1-75mh-jantzen-air-core-wire-coil.html

westmassguy

gmcman wrote: »

westmassguy wrote: »

The 1.8 needs to be unwound. and would advise checking all of them.

Just curious, when unwinding the inductors, are you using a certain freq when testing with an LCR meter? If so, what do you generally use?

Thanks.

The meter does that in the background, depending on what range I set it to.

JayCee

bem wrote: »

My only concern is the whether my amp can handle the drop in impedance that is created with the new inductors. I’m using a Parasound A21 and I was wondering if anyone has done the inductor upgrade and is using a A21.

I have heavily modded CRS's, 1C's and 1.2tl's with all inductors, including oversized/low impedance SDA inductors, upgraded on each and my HCA-1500As (2 of them) have been very happy for the past 6 years. Never run too hot, no clipping and rock solid. Comparing specs from each amp you should have no problem.

From the Parasound website:

HCA-1500A
Continuous Power Output - Stereo:
205 Watts RMS x 2, 20 Hz-20 kHz, 8 Ω, both channels driven
315 watts RMS x 2, 20 Hz - 20 kHz, 4 Ω, both channels driven
Continuous Power Output - Mono:
630 watts RMS, 20 Hz - 20 kHz, 8 Ω
Current Capacity:
60 amperes peak per channel

A-21
Continuous power output:
250 watts RMS x 2, 20 Hz - 20 kHz, 8 Ω, all channels driven
400 watts RMS x 2, 20 Hz - 20 kHz, 4 Ω, all channels driven
750 watts RMS x 1, 20 Hz - 20 kHz, 8 Ω

Current capacity:
60 amperes peak per channel

gmcman

westmassguy wrote: »

The meter does that in the background, depending on what range I set it to.

Yes...that's what I'm curious about....what frequency do you set the meter at? The inductor in question...the 1.80 being unwound to 1.75.

JayCee

@gimpod provided a helpful post from several years ago re. SDA inductors...in case curious minds haven't seen or have forgotten it:

https://forum.polkaudio.com/discussion/138234/inductor-dcr-insanity-for-sdas/p1

VR3

DATS software is great for measurements

pitdogg2

gmcman wrote: »

westmassguy wrote: »

The meter does that in the background, depending on what range I set it to.

Yes...that's what I'm curious about....what frequency do you set the meter at? The inductor in question...the 1.80 being unwound to 1.75.

Test them all. All of mine were all over the place under, over, way over. Then make them all as close as possible and match to each other as best you can.
It will make a difference as I'm sure you know.

westmassguy

gmcman wrote: »

westmassguy wrote: »

The meter does that in the background, depending on what range I set it to.

Yes...that's what I'm curious about....what frequency do you set the meter at? The inductor in question...the 1.80 being unwound to 1.75.

I set the Inductance range, not the frequency.

Schurkey

JayCee wrote: »

Current capacity:
60 amperes peak per channel

Yeah, but that's a totally useless spec unless they used a musically-relevant test protocol to generate that figure.

Driving a dead short for 0.0000000000001 seconds doesn't give results that matter in the real world.

westmassguy wrote: »

gmcman wrote: »

westmassguy wrote: »

The meter does that in the background, depending on what range I set it to.

Yes...that's what I'm curious about....what frequency do you set the meter at? The inductor in question...the 1.80 being unwound to 1.75.

I set the Inductance range, not the frequency.

I think what he's trying to get at is that the indicated inductance changes with frequency; so what is the frequency used for testing? My meter has a couple of choices, but it's been so long since I've used it that I don't remember what the choices are. Perhaps 1KHz and 2KHz?

westmassguy

The frequency for a given Inductance range is not listed on my meter, only the inductance is. It's probably in the manual, which is packed away somewhere.

RobbyKY

Big difference in the readings at various frequency settings for inductance meters. Setting mine to 120Hz gets me really close to the stock ratings. The 1KHz setting reads significantly higher than the stock ratings on Jantzen, Erse & Solen and the reported results of Polk OEM bobbin-wound coils depending on the size. The higher the "L", the further off. It seems to like air-cores better than the iron-core versions. The Erse offerings seem to read further off at the 1kHz setting.

My meter (which I "borrow" from work when needed) is an Extech 380-something that gets calibrated by an outside lab every 6 months.

F1nut

Interesting discussion. Does anyone know how Janzten, Erse or Solen measure theirs?

RobbyKY

Hang on, L reads lower at higher frequency test settings while the resistance reads higher on my Extech. Need to get some sleep. The lower "L" Solens and Jantzens read really close to ratings at the 120Hz setting on this thing. These Super Q's were going into a 3.1 rebuild so I was unwinding down to 18. I ran them down to 18.5 to allow for the Extech variation. I assume Erse has better equipment but I have a mess on my hands with the mate to this 20. It was reading 22 out of the box.....

Erse 20.000 mH Super Q at 120 Hz reading 20.53.


Same Super Q reading 19.76mH at the 1kHz setting

westmassguy

When measuring the SuperQs, or any Steel or Iron Core Inductors, make absolutely sure they're nowhere near any type of Magnetic or Ferrous Metals. This includes metal capped work tables, and even hidden screws.

RobbyKY

Amen to the "avoid metal workbench" comment^^^^.

Mine is non-magnetic engineered resin. I played around with the big OEM Polk 18mH inductor and the stock steel bolt that came with it. Note the influence adding the steel 1/4" bolt through the center of the air-core winding has on the measurements. Makes you wonder if Polk designed for this or if it was a cost-cutting move made by manufacturing some time later? I purchased non-ferrous bolts to hold my dreadnought isolation transformers in the housings and they are considerably more "costly" than normal steel versions.

Freq 18 mH SDA (22awg)

Without the stock bolt
120 hz 17.874mH 6.57Ω
1 kHz 17.831mH 6.69Ω


With the bolt
120 hz 19.557mH 6.85Ω
1 kHz 18.593mH 10.24Ω

pkquat

I don't have my LCR manual in front of me, and I figure @westmassguy would have mentioned it if it were necessary. But, just in case, if I recall correctly, for many LCR's, depending on the inductor value you are checking, there is a preferred frequency. Some values do overlap frequences, and depending on the inductor value an internal calibration is required, meaning either the leads are shorted or left open before taking a reading. Just changing the frequency without this step can give different values.

gmcman

Schurkey wrote: »

I think what he's trying to get at is that the indicated inductance changes with frequency; so what is the frequency used for testing?

Correct, doesn't seem to vary much between 100-120Hz, but more around 1kHz.

westmassguy wrote: »

I set the Inductance range, not the frequency.

Copy thanks...no worries.

RobbyKY wrote: »

I played around with the big OEM Polk 18mH inductor and the stock steel bolt that came with it. Note the influence adding the steel 1/4" bolt through the center of the air-core winding has on the measurements. Makes you wonder if Polk designed for this or if it was a cost-cutting move made by manufacturing some time later?

Interesting, my small OE bobbin coils measured very good, the woofer coils not so much, but the big coil was off about like yours, I will recheck mine without the bolt.

RobbyKY

pkquat wrote: Some values do overlap frequences, and depending on the inductor value an internal calibration is required, meaning either the leads are shorted or left open before taking a reading. Just changing the frequency without this step can give different values.

I always run the lead calibration step as force of habit. Hit "SET" twice, remove leads, hit "Enter". When "CAL SHrt" displays, attach & short leads and hit "ENTER" again.

I did go back and read the Extech owner's manual just now. Interestingly it has a note that says 120Hz is mainly used for "Large Electrolytic Capacitors" while the 1kHz setting is used for "most other test". Can honestly say I never noticed that before, always a learning experience but of course it seems this meter gets closer to the listed values of the coils on the 120 setting. Now I'm going to need to go play around.

I ended up ordering two new 18mH Super Q's directly from Erse last week for my 3.1 project since PE only stocked the 20's and found Erse doesn't even list a 22 mH as an option. Probably should have returned them to PE before I unwound but now I have these just sitting around. Traveling the rest of the week but I may get medieval on them next week and try to understand what's going on with 'em. I've got an x-ray, SEM, XRF etc at my disposal, I'll pot them up, section and see what's really different between them.

Here's where I was with the two labeled 20.000mH parts on the 120Hz setting:

#1 20.53mH, 0.91 ohms, 1.23mm wire OD and 763.7 grams.
#2 22.67mH, 0.84 ohms, 1.24mm wire OD and 765.0 grams.

And here's where I was when I finished:

#1 18.01mH, 0.84 dcr and 729.2 grams. I removed 34.5 grams of copper
#2 18.02mH, 0.71 dcr and 700.3 grams. I had to remove 64.7 grams of copper

See why I didn't trust what was happening? Started out at the same weight but had to remove twice the copper to get down to 18? Core stack measured the same height and the overall weight was the same but #2 started out 2mH over listed rating then required removal of twice the copper. Perplexing huh?

pitdogg2

My super Q's from Erse were off and mislabeled. One 18mH was 20mH or above IIRC. I expected there to be some +/- % but the 20+ would have made a substantial difference one would think.

westmassguy

I measure everything now, even from Jantzen. When I'm upgrading crossovers, I always measure the old Polk inductors. They are rarely what they're supposed to be. I did a pair of 3rd Gen SRS-2s, one sub-bass spool was 9.6mH, the other was 16mH.
My LCR measures at 1KHz BTW.

RandyCroissant

westmassguy wrote: »

I measure everything now, even from Jantzen. When I'm upgrading crossovers, I always measure the old Polk inductors. They are rarely what they're supposed to be. I did a pair of 3rd Gen SRS-2s, one sub-bass spool was 9.6mH, the other was 16mH.
My LCR measures at 1KHz BTW.

That is a big difference, I think I may invest in a LCR meter any recommendations Dave