[OSIB16]

I recently acquired a nice pair of Sonus Faber Concerto bookshelf speakers. They are the more desirable Mark 1 version. Amazing condition, with real walnut and leather cabinets. These things have got some serious potential, so I’m looking forward to upgrading the crossovers, including some modifications to the internal cabinet structure, which will add overall strength, and significantly reduce vibrations.










Here is a list of the tasks below…


1) REPLACE EXISTING FILM CAPACITORS

2) REPLACE RESISTORS

3) NEW UPOCC NEOTECH WIRE (TEFLON SLEEVES REMOVED AND SUBSTITUTED WITH PURE COTTON)

4) ALL WIRING TREATED WITH DEOXIT TO PREVENT ANY FUTURE OXIDISATION.

5) SPEAKER CABLE HARDWIRED DIRECTLY TO CROSSOVER.

6) NEW WIRE INDUCTORS.

7) CHANGE FROM BIWIRE TO SINGLEWIRE.

[OSIB16]

[S Clark]

Whichever of those iron core inductors goes directly to the woofer, I'd replace with an air core.  Certainly upgrade the tweeter cap and resistor. 
Iron core inductors, sand cast resistors... not what you'd hope for in a $2K bookshelf speaker. 
Hope you got a good deal on them. 

[OSIB16]

S Clark,
            Bought them for £415 (UK STERLING). The seller delivered them to me in person. The small red colour Iron Core Inductor is closest to the woofer, and agree with you about swapping it for an Air Core. However I will also replace the remaining inductors for Air Cores. I wonder if Sonus Faber will let Know know their Millihenri values? Will probably have to send them off to be properly measured. Do you reckon I should swap the 3.3uf Film Cap on the tweeter for a 2.2uf cap like the Mundorf Supreme Silver Gold?

[OSIB16]

I would like to fix that dip in the treble

[S Clark]

I would like to fix that dip in the treble

That first dip looks like a phase issue... possibly the result of the first order crossover on the tweeter. If you had a way to measure it, I'd try reversing the polarity on the tweeter and see what happens.   As far as testing the Henry measurements of the inductors, it would be as cheap to buy a meter as it would be to send them to be measured.
 https://www.amazon.com/Honeytek-Capacitance-Capacitor-Electronic-Measuring/dp/B08LYM533X/ref=sr_1_28?crid=23BAAB8QF5MHV&keywords=capacitance+multimeter&qid=1674623561&sprefix=capacitance+m%2Caps%2C314&sr=8-28

That looks like a nice woofer.  Contact Danny Richie to see if he has a crossover upgrade available for these speakers.  He's about as good as anyone in the business on passive crossover design. 

[OSIB16]

That first dip looks like a phase issue... possibly the result of the first order crossover on the tweeter. If you had a way to measure it, I'd try reversing the polarity on the tweeter and see what happens.   As far as testing the Henry measurements of the inductors, it would be as cheap to buy a meter as it would be to send them to be measured.
 https://www.amazon.com/Honeytek-Capacitance-Capacitor-Electronic-Measuring/dp/B08LYM533X/ref=sr_1_28?crid=23BAAB8QF5MHV&keywords=capacitance+multimeter&qid=1674623561&sprefix=capacitance+m%2Caps%2C314&sr=8-28

That looks like a nice woofer.  Contact Danny Richie to see if he has a crossover upgrade available for these speakers.  He's about as good as anyone in the business on passive crossover design.

Thanks for the tip, valuable info. However; Jeff’s going to help me get these things up and running.

[jbl]

You may also want to try adding a bypass capacitor for the tweeter and woofer.  Can really improve SQ.  I just helped my friend add two to his Spatial M4's.  Dramatically increased the size of the sound stage, increase detail and decay.  A significant improvement for a speaker that already sounds fantastic. 

[Stimpy]

...Do you reckon I should swap the 3.3uf Film Cap on the tweeter for a 2.2uf cap like the Mundorf Supreme Silver Gold?

I wouldn't change to a capacitor with a value other (smaller) than stock.  That would shift the crossover point higher in frequency, and probably cause a even bigger treble dip.

Also, any new capacitor will most likely have a different ESR (equivalent series resistance) reading than stock.  Could be higher, but usually lower.  That will affect the output level of the tweeter.  So, the tweeter's resistor might need to be changed to a greater resistance, to rebalance the tweeter to the woofer.  I'd get several resistors, with different values, to experiment to see which sounds best.

Oh, you'll most likely need a new crossover board for the woofer circuit.  Air core inductors will be much larger...!

Good luck.

[OSIB16]

JBL + Stimpy
                    I’m sticking with the same values, but Jeff is helping me to ensure that the replacement parts will be more precisely suited to this particular speaker model.

[johnss]

Dear sir, what did you use to remove the black compound coating the crossover? do you have any techniques you could share?
I have a pair of Minuettos I am going to do a similar upgrade to.

Appreciate any input/advise you can offer.

thank you.

[OSIB16]

It was very difficult to remove the black goo with a screwdriver. I only removed some around the areas of the capacitors which reveal the values.  As for the Concerto modifications; I have purchased all the replacement parts (exotic capacitors, resistors, coils etc) from Sonic Craft. However I have not got round to installing them into the speakers yet due to a car project that I’m currently busy with. When I get time to work on the Concerto’; I will be doing all point to point wiring on brand new breadboards. The original circuit boards will be thrown out or sold on EBay.

Dear sir, what did you use to remove the black compound coating the crossover? do you have any techniques you could share?
I have a pair of Minuettos I am going to do a similar upgrade to.

Appreciate any input/advise you can offer.

thank you.

[johnss]

thanks very much.

[OSIB16]

No problem. My other advice would be to install half of the new components inside the speaker cabinets, and the rest in a box attached to the rear. Otherwise you won’t be able to fit in the oversized capacitors and coils.

thanks very much.

[Spamela]

Looking for an update on this project if there is one.
I too have a pair of these speakers. I picked mine up at a garage sale for $50. Both speakers and matching stands. Cosmetically in great shape, but 3 of the drivers were blown. (Both tweeters and one woofer) I was able to repair the woofer as the solder joint from the braided connection wire to the voice coil wire was burned at the joint on the cone. The tweeters were shot. I did a direct replacement of them with a pair of Hiquphon OWI-fs. In the end, the price of the Hiquphons were slightly cheaper than the branded Sonus Faber OE replacement. Of course, I do not have anything to make a direct comparison to, but to my ears, the best part of these speakers now is the tweeter section. The resolving power of the upper range is significantly better than the woofer section. The woofer sounds a bit wooly and slow in comparison. I did a brief measurement with REW with a radioshack meter feeding it and the transition from the woofer to the tweeter is as flat as could be. So, this is a great replacement option. I have not made any changes to the crossover. So, very happy so far at this point. But I've been thinking to upgrade the crossover now to see where I can take these. I was thinking there could be a great improvement replacing those iron core inductors, and of course, the caps are 20 years old. I think complete new crossovers would be the way to go. So, I am really interested to see how your project turns out. If it all goes well, I would probably follow in your footsteps. I'd prefer to build some crossovers base on your success, then do a direct swap. Please keep us informed. Regards.

[OSIB16]

Looking for an update on this project if there is one.
I too have a pair of these speakers. I picked mine up at a garage sale for $50. Both speakers and matching stands. Cosmetically in great shape, but 3 of the drivers were blown. (Both tweeters and one woofer) I was able to repair the woofer as the solder joint from the braided connection wire to the voice coil wire was burned at the joint on the cone. The tweeters were shot. I did a direct replacement of them with a pair of Hiquphon OWI-fs. In the end, the price of the Hiquphons were slightly cheaper than the branded Sonus Faber OE replacement. Of course, I do not have anything to make a direct comparison to, but to my ears, the best part of these speakers now is the tweeter section. The resolving power of the upper range is significantly better than the woofer section. The woofer sounds a bit wooly and slow in comparison. I did a brief measurement with REW with a radioshack meter feeding it and the transition from the woofer to the tweeter is as flat as could be. So, this is a great replacement option. I have not made any changes to the crossover. So, very happy so far at this point. But I've been thinking to upgrade the crossover now to see where I can take these. I was thinking there could be a great improvement replacing those iron core inductors, and of course, the caps are 20 years old. I think complete new crossovers would be the way to go. So, I am really interested to see how your project turns out. If it all goes well, I would probably follow in your footsteps. I'd prefer to build some crossovers base on your success, then do a direct swap. Please keep us informed. Regards.

Ok, so I have already received all of the main new replacements parts from Jeff. However, I have not yet got around to fitting them into the Concertos speakers, due to a car project that I am currently working on right now.

Below is a list of the super exotic components that Jeff supplied me for this Sonus Faber Concerto speaker modification:




TWEETER PARTS
—————————

TWO VISHAY MILLS 1ohm MRA-5 RESISTORS

TWO MIFLEX KPCU-02/3.3uf FILM CAPACITORS

20awg JUPITER SOLID CORE WIRE (99.99% PURE COPPER) - purchased from different source.




MID WOOFER PARTS
———————————

TWO ORIGINAL MILLS MRA-12 RESISTORS - 15ohm

TWO SONICAP GEN 1 FILM CAPACITORS - 3.3uf / 400v

TWO SONICAP GEN 1 FILM CAPACITORS - 2.2uf / 400v

TWO VISHAY MILLS MRA-5 RESISTORS - 1ohm

TWO VISHAY MILLS MRA-5 RESISTORS - 2.2ohm (purchased from different source)

TWO ALPHA CORE RIBBON INDUCTORS

TWO SOLEN AIR CORE INDUCTORS - 36mh (purchased from different source)

TWO SOLE AIR CORE INDUCTORS - 91mh (purchased from different source)

NEOTECH 16 GAUGE SOLID CORE COPPER - for jumper wires to mid woofer units