Sonus Faber Grand Piano Domus x-overs

[NJPOLKER]

I am giving thought to removing the x-overs from my Grand Piano Domus speakers and upgrading the capacitors and resistors.

I have done this to some of my Polk Audio speakers in the past. The awesome members on the Polk Forum assisted in great detail how to successfully complete this upgrade.

The GPD sound really really good and I can't leave well enough alone
Soooooo I need some advice. Is this something I should consider? Have any of you guys/gays done something like this?

Thanks

[Glisse]

Originally Posted by NJPOLKER

I am giving thought to removing the x-overs from my Grand Piano Domus speakers and upgrading the capacitors and resistors.

I have done this to some of my Polk Audio speakers in the past. The awesome members on the Polk Forum assisted in great detail how to successfully complete this upgrade.

The GPD sound really really good and I can't leave well enough alone
Soooooo I need some advice. Is this something I should consider? Have any of you guys/gays done something like this?

Thanks

Yes, I have.

I replaced the 3 cement resistors with Mills. I doubt whether the resistors themselves will affect the sound quality much, but the OEM resistors are unfortunately placed directly on the circuit board, 2 across with 1 sitting on top in the middle. They should have been on risers. After 2 hours of high output, the resistors will heat up the board so much that the solder will melt, the capacitors and inductors will fall off, and you will short the amp.

By using Mills resistors, you can sit them up on their leads above the board, and fan them out, which will give much better heat dissipation

The capacitors in the Domus GP are not good - Taiwanese electrolytic. Change them for a film cap of your choice. I used Jantzen, but you could try Mundorf Supreme (which SF use in their premium speakers) or Clarity Cap, etc.

The caps on the bass aren't so critical, but I changed them all. But if you are going to make just one change, put a film cap on the HF driver. It makes a big difference

Be aware that the film caps are massively larger than electrolytic caps. This exercise will be like trying to fit several elephants into a small tent. You will need to go up, stacking them and using plastic ties to secure them in place. I ran a couple in parallel which makes it easier, but adds to the cost. Keep to the same values as SF used. They may have used cheaper parts in this model (my Concerto Grand Piano had much better crossovers - so the voice coils went before the crossover!), but the design is good

And I am a guy, not gay. Not that there's anything wrong with that...

[sknutson]

I own a pair as well an have zero experience. Wondered first if you can tell me what the upgraded X over did for the sound of the speakers? Secondly how dificult is the conversion? My speakers are rather new and in my opinion not as transparent as my Magnapan 3.6's that they replaced with the identical electronics. Any help is appriencted.

Cheers

[NJPOLKER]

My plan right now after doing some research is to replace the existing Bennic BP03 capacitors 50 mfd and 22 mfd with Mundorfs. Any suggestions?


One of my advisors suggested I leave the MOX resistors alone for now. Thanks Mike!!


madisoundspeakerstore.com/mundorf-mcap-evo-oil-caps/mundorf-22mfd-evo-oil-capacitor/

madisoundspeakerstore.com/mundorf-mcap-evo-oil-caps/mundorf-47mfd-evo-oil-capacitor/

[Nikon1975]

Hi,

Do you have the schematic of the x-over? I bought the speakers second hand and I suspect that they have been tweaked before. Do you also have a round black piece of stuffing just behind the bass reflex tube?

Last: how did you extract the x-over?

Thanks,

Davide

[Masterlu]

Nikon1975... Welcome to AA!

[jdandy]

Nikon1975.......Welcome to Audio Aficionado.

[Glisse]

No schematic, don't recall any round black stuffing. The whole speaker is filled with wadding, maybe this is what you are seeing. This acts to effectively increase the size of the enclosure, as "seen" by the drivers.

Carefully remove each driver - the wiring is attached via friction tabs. Dismantle rear terminal block. You will be able to access the crossover through the openings for the bass drivers. IIRC, it is just screwed directly into the rear wall, so unscrew and then pull out.

[Nikon1975]

Thanks,

I'll try to post a picture of what I found behind the bass reflex duct. I am having a bit of problems with these speakers, the sound is like disconnected, like the drivers are singing on their own. I might have problem outside the speakers:
1) I do not have a dedicated room. The speaker are in the living room and the structure is not symmetric.
2) I am driving them with a Pass Firstwatt F5-X. This is a balanced version of the F5 with 30W class A power.

I first was thinking just to sell these speakers, I have the concerto home that do very well. But I am tempted to give it another try. I have various things in my mind:
1) Try a more powerful amp. I have a Denon 3808 that I can use straight away, but I was actually thinking of putting together an ice power 500A based amp.
2) I am tempted to pull the x-over out and bi-amping the speakers, leaving the pass amp for the mid-high and a more powerful unit (ice power?) for the bass.

When I started trying to disassemble the speaker I got the feeling that this was modified before. One thing that I always noticed is that the Denon Audissey claims that the speakers are out of phase.

D.