Vintage HiFi Audio Forum
Audio Discussion => DIY => Topic started by: F1nut on February 18, 2015, 11:22:19 PM
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Kingman asked me for this the other day via email and now ataudio on the forum, so here is my take on the Dennis Murphy engineered mod turned up a notch or two.
Parts List from Parts Express:
(2) Vifa tweeters #264-1040
(2) Jantzen 0.50mH inductors #255-036
(2) Jantzen 1.5mH inductors #255-260
(1) Sonic Barrier 1/2" thick #260-520
(1) #6 x 3/4" screws #081-435
Instead of using the stock low pass 1.0mH inductor and adding a 0.50mH 20 AWG to it, I replaced it with the Jantzen 1.5mH 18 AWG with a DCR of 0.67 ohm.
Optional: I replaced the stock binding posts with #260-309. You will need to remove the binding posts from that part and install them on the stock binding post plate because you need the 4 plastic posts to support the new board. The reason I did this is because the connectors on the back of the stock posts are not gold plated and already looked like they had oxidation.
Optional #2: I upgraded the stock 20 ga. chassis wire from the board to the drivers with 16 ga. If you do this you will need to get new female disconnects from PE.
(1) .205" #095-282
(1) .110" #095-286
Parts List from Sonic Craft:
(2) Sonicap Gen I 3.9uF 200V (they only have 4uF, which will be fine)
(4) Sonicap Gen I 2.2uF 200V
(2) Sonicap Gen I 10uF 200V
(2) Mills .33 ohm/12 watt resistor
(2) Mills 6.8 ohm/12 watt resistor
Instead of using the existing 2.2uF in the high pass I replaced it with the Sonicap Gen I. Also, instead of using the stock 10uF in the low pass I replaced it with the Sonicap Gen I. Again, instead of using the stock resistors they were replaced with Mills 12 watt.
The new Vifa tweeter requires you to enlarge the notch at the bottom of the tweeter mounting flange and make a new notch at the top to accommodate the terminals.
I get my black FR4 from www.AmericanEpoxy.com (http://www.AmericanEpoxy.com) and use the .094" thickness. They have a $25.00 minimum, so if you order a 12" x 24" sheet that will meet the minimum. The shipping cost will run $18 to $20 I guess. You will need to cut 2 sheets, size 2 7/8" x 5 1/2", so plenty of leftover. Cutting this stuff is best done with a wet tile cutter to keep the dust down, but a table saw or band saw will work too. Do NOT breath the dust.
Here's the thread on AK where a guy talks about cutting the Sonic Barrier to size and has the new schematic posted. http://www.audiokarma.org/forums/showthread.php?t=610820 (http://www.audiokarma.org/forums/showthread.php?t=610820)
A few other things you will need, 3M VHB tape to help secure the parts to the board and plastic zip ties to further secure them. You will note in my photos a screw at the top of the board when installed. I wasn't happy with the board unsupported up there, you may feel differently. I used nylon spacers and a 2 1/2" long round head wood screw shimmed up on the top side of the board making the screw length 2 1/4" otherwise it will go through the back of the cabinet. You'll probably find it easier to install all of this by using a sharp chisel to shave off an 1/8" from the bottom edge of the binding post opening.
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Having problems getting pics to post, looks like I can only do one at a time.
Pic 1 - stock
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Pic 2 - stock
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Pic 3 - new top view
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Pic 4 - new side view
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Pic 5 - new bottom view
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Pic 6 - new P2P
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Pic 7 - new installed
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Pic 8 - new installed close up
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F1,
I have the BS21 (previous version of the BS22). Do you know if the woofer is the same in both versions? If no, might the difference be small enough that this new crossover work for the BS21 woofer too?
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I don't know if they are. However, if you pull the crossover you will be able to compare the values to the BS22 and if they are are the same then this mod will work for your speakers.
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I don't know if they are. However, if you pull the crossover you will be able to compare the values to the BS22 and if they are are the same then this mod will work for your speakers.
Thanks Jesse. They are in a box somewhere in storage. Will take a look when I find them.
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Thank you very much Jesse. That is superb construction. Don't want to over stay my welcome but if you comment on the sound that would be great. Typically small speakers sound...well..."small". Not that I expect 20hz from a 4 inch woofer but I am curious as to your comments. I have some Best Buy gift cards that wont buy me any worthwhile photo gear there but will but help offset the cost enough to justify the mods. Thanks again for you time.
(Shhhh. Sonicap. Gen 1. (Insert thumbs up here))
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exc craftsmanship - the component labels are aligned just right. looks great. sound?
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The sound.....for the $350.00 I've got into them the sound is quite good. Much better than one would expect from a budget speaker. In stock form they were a bit boomy and edgy. After the mod I could tell right away that the highs were smoother, more refined. The bass was a bit better, but still not as tight as I would like. So, I now have about 180 hours on them and the bass has tightened up nicely and has punch, it's actually impressive for such a small driver. The high's/mid range have continued to improve with nice detail. The sound stage is good, extending beyond the speakers. They are an easy speaker to listen to, musical. Overall, well worth the effort.
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Jesse - I think you meant to write 18 and instead wrote 180.
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No, I meant 180 hours.
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I understand now - you mean 180 hours of burn-in, not 180 hours of work to build the x-over.
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Ah yes, that's correct. I'm not sure how long the actual work time was as I didn't keep track.
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Most excellent Jess! Thanks for taking the time to show us your fine work!
Did you find stand for these yet?
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Thanks Carl. I haven't found a Sanus stand, but did find this http://www.liedtke-metalldesign.eu/epages/64011114.sf/en_GB/?ObjectPath=/Shops/64011114/Products/LM-IQ-03/SubProducts/LM-IQ-03-0001 (http://www.liedtke-metalldesign.eu/epages/64011114.sf/en_GB/?ObjectPath=/Shops/64011114/Products/LM-IQ-03/SubProducts/LM-IQ-03-0001)
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So, has anyone completed their mods yet?
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No... trying to get a group build going with a few others.
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Slackers >:D
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Slacker! Well...yes. But here's why. I pulled my old home theater speakers out of storage....A pair of the original NHT SuperOne, a pair of NHT SuperZero and SuperCenter. Have you ever heard the SuperOne's? Just wondering how they would compare to a pair of hot-rod Pioneers. I also have another outstanding project....my Advent NLA crossover upgrade...new Sonicaps, 12 gauge air core foil inductors, cabinet tweeks, etc. Biggest limiting factor is a wife that can't stand this hobby. Gotta tiptoe around ever wavering female hormones :(
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I have not heard the SuperOne's, but I do have a pair of modified SB3's, which I enjoy very much. I haven't made a direct comparison because a rear ported speaker such as the Pioneer will not work in the location where I use the NHT's.
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An update.....
What a difference a great speaker stand makes. Having searched everywhere, everyday for a pair of Sanus UF30 stands I had given up. So, the day I was going to place my order for the Liedtke-Metalldesign stands from Germany I took one last look and damn, a pair on Craigslist shows up in Seattle. I quickly made arrangements for them to be picked up and shipped to me by a great guy named Jeff at Club Polk......thank you!!!
Let me tell you, going from the 5 lb. wooden Sanus NF stands with the tweeters at 37.5" to the UF30's with the tweeters at 40" and weighing in at 18 lbs. empty was one of those wow moments. Simply put, mo'better sound! I will be mass loading the stands with a combo of lead shot and sand, which will add about 35 lbs. to each stand and may just improve the sound a tad more, we'll see. I wasn't exactly displeased with these modded Pioneer bookies, but man they just went up a few notches.
The moral of this story, the right stands make all the difference and cheap ones are cheap for a reason.
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Perseverance pays off. I've never seen that brand up close but I see from google they are spiked top/bottom.
Is that how you use them? I've always preferred spikes on the floor and blue tack for the speaker coupling.
More so for safety sake. The blue tack really clamps the speaker to the stand...won't slip off if bumped....and they perform as one mechanical assembly.
Spikes....geeez, I remember when the Mod Squad first brought spikes into the mainstream. The mechanical diode.
I still want to build a pair....anybody wanna buy a set of classic NHT super zeros, super ones and a super center.
Piano finish, glossy black. Excellent condition!!
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Very nice Jesse!
I am familiar with the Sanus stands. Did you use Blue Tack as ataudio noted or another method to anchor the speakers to the stands? Thanks for your post.
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They have an option to use spikes on the top plate, but another to use rubber pads. I used the rubber pads to decouple the speakers.