SDA-2B Crossover Parts List

inspiredsports

forgot the pics

Face

Why add more links to the chain?

Cut the old connector off and either crimp the smaller one onto the cable or solder the cable right to the terminal.

inspiredsports

Face wrote: »

Why add more links to the chain?

Cut the old connector off and either crimp the smaller one onto the cable or solder the cable right to the terminal.

It just seems valuable (to me anyway) to be able to go back to the stock setup with no cutting, crimping or soldering if it can be done with a quality adapter.

Assuming a precious metal plated part, do you think it will diminish the sound quality? In fact, do you think the cheap plated parts I'm using are hurting sound?

inspiredsports

Yes I know it's not supposed to happen this quickly, but the phantom center channel was pretty much missing until now and just magically appeared while Sting was crooning "King of Pain" from the Synchronicity CD. Soundstage seem a bit wider, tweeters are a bit mellower.

inspiredsports

Parts were off at Ben's for the holidays for the addition of Cardas CCGR posts since 12/18/08 until last night. I'm not sure why I didn't post in between, but they had 57 hours on them when I shut them down and sound was coming along nicely.

Recapping, crossovers were upgraded to TL status to move up from the RDO194-1 to the RDO198-1 using all Sonicap brand caps and mills. The RDO198-1 was installed and passive radiator was covered with Dynamat Extreme. 6-1/2" Mids had not been Dynamat-ed, and Mortite had not been applied.

Last night I finished that up, using a much smaller amount of Dynamat Extreme than on the passives (1 piece 7/8" wide X 2" long on each of the 4 spokes on each 6-1/2"). I also used Mortite to seal the round plastic binding post/sda cable mount on the back, and each driver (RDO198-1, 6.5's and 10" passive) into the cabinets.

I laid each speaker on it's back, carefully pressed the Mortite to the rim of the drivers, and heated the Mortite with a hair dryer, then carefully lined up the holes and set each in place. Each screw was put in place while the Mortite was still quite warm snugged down just a bit. I let gravity work for about an hour and snugged them up a bit more before putting them in playing position.

I will be tightening each driver/passive screw just a small amount in a criss-cross pattern every day until I'm convinced they as tight as possible without warping the driver frames. I won't push high SPL's until then.

While the speakers were on their backs I removed all 4 side panels because the 20+ year old glue is losing its grip. A 2" bit of the walnut veneer on the bottom of the left channel also needs to be re-glued.

I may come back to the SDA-2B 1 more time to adapt it for the AI-1 so I can bridge, because it is in the proper serial number range to do so. I have cooled my jets on this idea for now based upon feedback from many of those here in the group who know better than I. (but I do have the amps and cables here now and bridged it briefly last month with the Interconnect cable removed - it was still awesome!!)

My SDA TWEAKING CHERRY HAS BEEN POPPED !!! I'm almost done and ready to turn my full time attention to my more complicated SDA SRS 2's with one rebuild under my belt.

Conradicles

This is a fantastic thread and will help me out a bunch when the time comes to upgrade mine. Thanks for the detailed pictures inspiredsports. Good job!:)

ben62670

Those post are nice, and solid:)

inspiredsports

Conradicles wrote: »

This is a fantastic thread and will help me out a bunch when the time comes to upgrade mine. Thanks for the detailed pictures inspiredsports. Good job!:)

I feel like I'm really just the photographer , but I'm doing it precisely so others who come after have another lifeline.

F1, Face, Ben, Zingo, MillerLiteScott and others here are the real architects.

I'm holding off on opinions about the sound as the caps and RDO's are no where burned in. Plus, just 24 hours ago, I decided to burn in some of the AVt Cable Interfaces and Interconnect I'm selling so thes puppies sound a bit "gamey" (as in uncooked venison) :eek: .

Face

inspiredsports wrote: »

I'm holding off on opinions about the sound as the caps and RDO's are no where burned in. Plus, just 24 hours ago, I decided to burn in some of the AVt Cable Interfaces and Interconnect I'm selling so thes puppies sound a bit "gamey" (as in uncooked venison) :eek: .

Just curious, which AVt's?

And you haven't had gamey until you've had Elk, yuk!

ben62670

With all that new stuff I would leave them running for at least 80hrs when leaving the house. I can't imagine it sounding too good right about now.
BTW elk is very good. My buddy got a few when he lived in CO. Yummy

inspiredsports

Face wrote: »

Just curious, which AVt's?

And you haven't had gamey until you've had Elk, yuk!

Hi Face,

I've actually done a lot of backpacking in the San Juans over the past 30+ years and have eaten a bunch of it. Slow, all-day cooked in a crock pot with lots of bacon make for a lot less gamey meal.

I was multi-gifted to the max this year and decided to try a complete set as I have pictured at . . .

https://www.polkaudio.com/forums/showthread.php?t=76817

I've connected CD to preamp and preamp to amp with the AVt 2 IC's and Amp to speakers with the AVt 2 Interfaces.

Greg

Face

Cool, I'm looking forward to hearing your impressions of the AVt2 vs Shotguns.

inspiredsports

Face wrote: »

Cool, I'm looking forward to hearing your impressions of the AVt2 vs Shotguns.

I just couldn't resist hooking them up and figured it won't even hurt my resale price as I'm low already and have several sets anyway. I've decided I'll use the AVt 2's until I get the new Sonicaps in the crossovers fully broken in (about 200 more hours). Then I'll get to work on aquiring the Shotguns with a good baseline for comparison.

inspiredsports

Woo Hoo!

AVt-2 8' Cables and 1m IC's and SDA-2B's have been cooked for over 500 hours for quite some time now and the sound is simply outstanding.

But . . . . . . the AVt-2's were placed on the F/S forum a couple of days ago because . . . . . my Shotgun Cables and IC's JUST ARRIVED from MIT; unpacking now, it's like Christmas morning AGAIN!

336+ more hours of anticipation to see what these new wires are capable of!



PS.: will someone pleeeeease go the the F/S and make me an offer on those AVt's before marital bliss becomes marital blast? (I've had to hide the weapons!) :eek:

DollarDave

gdb wrote: »

I'd gladly pay $20-$30 for a well filmed,step by step instructional DVD that shows how to do these (and others)!! Could be a source of income for someone so inclined.

+1. Ben?

inspiredsports

Yeah, he certainly fits the bill and has plenty of experience both rebuilding and filming. Have you seen his YouTube.com videos of him incinerating mids by running 110 volts through them? :eek: There outta be a law!

inspiredsports

I've just completed my (almost) final upgrade of the 2B's by building a very high quality 14' twisted-pair cable from 12 AWG silver-plated oxygen-free copper kapton and teflon insulated wire to replace the original 16-2 AWG 20' factory SDA Interconnect Cable.

I used blade/blade connectors (http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=248760&) so converting that to Cardas females on the back of the cabinets and decent quality bananas on the wire is about the only possible upgrade left. I'm not convinced the Cardas upgrade will yield a big bang-for-the-buck improvement so I'm holding off until I learn more.

audiocr381ve

I know many cool points will be deducted from my already empty cool points container for resurrecting this thread, but just to be clear....Stock inductors were not touched?

Joe08867

There is limited need to ever change out the stock inductors. Save your money on this and get the best Caps you can buy.

dorokusai

I'd buy modestly priced capacitors and think about inductors if it's easy to get them integrated. It's not cost that has ppl not change them, it's because it's hard to replace two components that are 3x the size of the original. When I build boards from the ground up, inductors are always in the mix. Do they go bad? Not by a long shot but there are better air core versions available for the most part.

inspiredsports

dorokusai wrote: »

I'd buy modestly priced capacitors and think about inductors if it's easy to get them integrated. It's not cost that has ppl not change them, it's because it's hard to replace two components that are 3x the size of the original. When I build boards from the ground up, inductors are always in the mix. Do they go bad? Not by a long shot but there are better air core versions available for the most part.

I'm curious about the opinion that better air core inductors are available as I don't know much about them. My observation has been that most here feel the originals are fine from a sound quality perspective and should be left in place.

--- What makes one inductor better than another
--- How do the originals used by Polk differ from what you would source today?

In other words, what was the compromise Polk made back in the day versus the best available today?

inspiredsports

audiocr381ve wrote: »

I know many cool points will be deducted from my already empty cool points container for resurrecting this thread, but just to be clear....Stock inductors were not touched?

I just noticed this question . . . Correct, the original 1987 air core inductors were not replaced.

dorokusai wrote: »

I'd buy modestly priced capacitors and think about inductors if it's easy to get them integrated. It's not cost that has ppl not change them, it's because it's hard to replace two components that are 3x the size of the original. When I build boards from the ground up, inductors are always in the mix. Do they go bad? Not by a long shot but there are better air core versions available for the most part.

I've been researching the posts on the forum regarding better quality inductors and am convinced they offer a bass improvement.

Yes, they are huge and require some re-engineering to neatly fit them in place and they also get into your wallet a bit, but you can't take it with you :biggrin:

As a side note, I'm thinking one should probably invest in room treatments (especially bass traps) before fooling around with the inductors.

Toolfan66

I was thinking today how good a set of 2Btl'ed SDA's would sound with a new inductor in place, as good as the 2B's sounded stock then tl'ed I could only imagine how good they would sound!! too bad I sold them to find out..

audiocr381ve

TOOLFORLIFEFAN wrote: »

I was thinking today how good a set of 2Btl'ed SDA's would sound with a new inductor in place, as good as the 2B's sounded stock then tl'ed I could only imagine how good they would sound!! too bad I sold them to find out..

I'm gonna do it, so I'll let you know

audiocr381ve

inspiredsports wrote: »

I just noticed this question . . . Correct, the original 1987 air core inductors were not replaced.



I've been researching the posts on the forum regarding better quality inductors and am convinced they offer a bass improvement.

Yes, they are huge and require some re-engineering to neatly fit them in place and they also get into your wallet a bit, but you can't take it with you :biggrin:

As a side note, I'm thinking one should probably invest in room treatments (especially bass traps) before fooling around with the inductors.

BTW, thanks for the response. I'm going to give it a shot.

inspiredsports

Joe08867 wrote: »

There is limited need to ever change out the stock inductors. Save your money on this and get the best Caps you can buy.

Thanks for your concern.

I could apply any component Duelund produces, but will probably stop at Clarity Cap or Mundorf Oil when I revisit the high-pass capacitors. The same goes for inductors, but the current experiment involves the extremely affordable $128 stash of Erse Super Q laminated steel core inductors that arrived today.

If you own quality amplification, lowering DCR is the reason to replace inductors and the Erse will add just .45 ohm to the circuit.

Erse required a 50 piece minimum to custom wind a non-stock 16mH 14 gauge Super Q, but suggested I run 2 each 8mH 14 gauge in series.

Jim Smolik at Erse Audio offered . . . "the performance (of 2 8mH in series) would actually be better since only half the magnetic flux will be in core.:

Jim further instructed when using this architechture, "keep the coils at right angles from each other and as far away as possible to prevent magnetic coupling."

I'll need some time to burn these in after the installation is complete, and will post some before and after FR curves and comments when everything has stabilized.

If I'm not happy with the results I will go straight to 16mH 10 gauge Solen air cores.

Greg

inspiredsports

More information specific to mounting Erse Super Q laminated steel core inductors in SDA's:

########## MY QUESTIONS TO ERSE ################################
Original Message

---

From:
Sent: Thursday, October 20, 2011 2:20 PM
To: Sales ERSE Audio
Subject: 2 Super Q installation questions

Hi Jim,

My Super Q's arrived last night and I have 3 more questions prior to installation.

First, I need to add a bit of wire from the crossover board to the mounting point of the first inductor, and then a bit of wire bewteen inductors as I'm placing 2 each 8mH 14ga Super Q's in series to get 16mH.

I guess my wire needs to be 14 gauge or heavier, but is there a specific material (copper/oxygen free copper/silver/etc.) that should be used for best results?

Second, to help me find the best location on the speaker cabinet floor, do you know exactly how many inches the flux field extends beyond the inductor?

Last, should non-magnetic fasteners be used to hold the bobbin ends down?

Sincerely,
Greg
Email:
Phone:

_end of message

########## ERSE RESPONSE ##################################################

---

Original Message

---

From: "Sales ERSE Audio" <sales@erseaudio.com>
To:
Cc: <sales@erseaudio.com>
Date: Thu, 20 Oct 2011 17:36:46 -0400
Subject: RE: 2 Super Q installation questions

Greg:

Do you have any Romex laying around the house ? Use the bare ground wire for your connections. Purity is very high and you will not notice the difference in sound quality with silver wire.

Use brass or aluminum screws to mount coils.

Mount coils at right angles at least three to four inches away from each other to prevent flux coupling.

Best regards,
The ERSE Audio Sales Team

email: sales@erseaudio.com
website : www.erseaudio.com

audiocr381ve

inspiredsports wrote: »

More information specific to mounting Erse Super Q laminated steel core inductors in SDA's:

########## MY QUESTIONS TO ERSE ################################
Original Message

---

From:
Sent: Thursday, October 20, 2011 2:20 PM
To: Sales ERSE Audio
Subject: 2 Super Q installation questions

Hi Jim,

My Super Q's arrived last night and I have 3 more questions prior to installation.

First, I need to add a bit of wire from the crossover board to the mounting point of the first inductor, and then a bit of wire bewteen inductors as I'm placing 2 each 8mH 14ga Super Q's in series to get 16mH.

I guess my wire needs to be 14 gauge or heavier, but is there a specific material (copper/oxygen free copper/silver/etc.) that should be used for best results?

Second, to help me find the best location on the speaker cabinet floor, do you know exactly how many inches the flux field extends beyond the inductor?

Last, should non-magnetic fasteners be used to hold the bobbin ends down?

Sincerely,
Greg
Email:
Phone:

_end of message

########## ERSE RESPONSE ##################################################

---

Original Message

---

From: "Sales ERSE Audio" <sales@erseaudio.com>
To:
Cc: <sales@erseaudio.com>
Date: Thu, 20 Oct 2011 17:36:46 -0400
Subject: RE: 2 Super Q installation questions

Greg:

Do you have any Romex laying around the house ? Use the bare ground wire for your connections. Purity is very high and you will not notice the difference in sound quality with silver wire.

Use brass or aluminum screws to mount coils.

Mount coils at right angles at least three to four inches away from each other to prevent flux coupling.

Best regards,
The ERSE Audio Sales Team

email: sales@erseaudio.com
website : www.erseaudio.com

That's really good info. I haven't officially mounted mine yet as I'm letting them burn in, but now I know what kind of screw to use.

inspiredsports

audiocr381ve wrote: »

That's really good info. I haven't officially mounted mine yet as I'm letting them burn in, but now I know what kind of screw to use.

Erse calls the clear plastic ends on the Super Q (with the screw mounting hole) the "bobbin". I'm going to place a 1"X2" piece of Armacell Armaflex between the bobbin and particleboard when I fasten the inductor to the floor of my 2B's.

audiocr381ve

inspiredsports wrote: »

Erse calls the clear plastic ends on the Super Q (with the screw mounting hole) the "bobbin". I'm going to place a 1"X2" piece of Armacell Armaflex between the bobbin and particleboard when I fasten the inductor to the floor of my 2B's.

If you wouldn't mind posting pictures, I think I'll wait until I have a model to replicate. What wire did you order for extending the xover cable to the new inductors?