Bottlehead and Zu

I finished wiring this about 10:30 last night. It took some willpower, but I decided to wait until this morning to fire it up. Of course, when I tried to pull out the speaker wires so I could hook it up, one thing led to another, and I wound up tearing apart my whole home theater. It's probably for the best; the dust puppies under it were well on the way to sentience!

HT Cleared Out.jpg
 
Who was I kidding, thinking I could wait until the neighbors wake up until I could vacuum and then test it. One Andrea Bocelli spin, coming right up!

First thoughts: It sounds amazing, but I can't quite get rid of the hum. The Kaiju has a pair of knobs to minimize the hum, but the Zus are so sensitive that it's never gone. I'll play with it a bit more and then build the DC filament supply. That add-on was made for super-efficient speakers like mine.

Still, once I got the music going and stepped back, "Gloria, the Gift Of Life" just about brought me to tears. I can't wait to hear how good it sounds as the day goes on, and I'm more comfortable cranking it.

Of course, I can't forget to put the system back together!

First Spin.jpg
 
I just installed the DC filament power supply. The hardest part of the install was getting to the original power supply wires. They were among the first wires installed and thus buried under several other wires and other components. While I had it apart, I decied to apply some tung oil to the base. I'll let the base dry overnight, put it back together tomorrow, and evaluate the difference in sound then.


Filament Power Supply.jpg

Tung Oil.jpg
 
Kits are their own rabbit hole. I'm already wondering if I should get their preamp kit (mostly stopped by the realization I have nowhere to put it).

I can also scour the multiple threads about capacitor rolling if I want to tweak this one.
 
I think I've just about gotten this wrapped up. All that's left is waiting for the oil to cure and then taping on the feet and badge (the feet are in place, just not stuck on—they're needed for airflow).

I have a couple final observations:
  • The 60 Hz hum is completely gone now that I added the DC filament supply.
  • Zu Soul Supremes are LOUD on a Kaiju. I originally had the Kaiju's trim pots set to max and adjusted the volume with the Valhalla. The tiniest touch of the volume knob took the sound from mute to blow-your-ears-off. I currently have the Kaiju's trim pots set somewhere between 5% and 10% and the Valhalla's volume knob around 50%. That gets me a comfortable listening level without fear of disturbing the neighbors. I'm afraid to crank it—I'll probably blow away the whole building!
 
apholden said:
I think I've just about gotten this wrapped up. All that's left is waiting for the oil to cure and then taping on the feet and badge (the feet are in place, just not stuck on—they're needed for airflow).

I have a couple final observations:
  • The 60 Hz hum is completely gone now that I added the DC filament supply.
  • Zu Soul Supremes are LOUD on a Kaiju. I originally had the Kaiju's trim pots set to max and adjusted the volume with the Valhalla. The tiniest touch of the volume knob took the sound from mute to blow-your-ears-off. I currently have the Kaiju's trim pots set somewhere between 5% and 10% and the Valhalla's volume knob around 50%. That gets me a comfortable listening level without fear of disturbing the neighbors. I'm afraid to crank it—I'll probably blow away the whole building!
Click to expand...


EDE99242-EF9E-434D-A527-7378B4E0A960.jpeg
 
The Dirty Weekends are "only" 97 dB/W. A little less than my Soul Supremes, but still amazingly efficient. Unfortunately, they have an odd impedance, which means you'll probably need loading resistors to match them to your amplifier. If my math is right, a 25Ω loading resistor will drop the efficiency by about 1/3, but I'm not sure how many dB that will cost you.

You should still only need a few watts to raise the volume to painful levels.

How big of a room do you want to fill, and are you looking to quietly play music while the baby sleeps in the next room, or do you want to light up the strip?

As for turnaround time, that's wildly variable. I got my Soul Supremes in about 3 weeks, while others mentioned a couple months. I would bet on the longer end of that range because their supply chain is still recovering from Lockdown.
 
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I just entered that 1/3 loss into a dB calculator at Decibel Conversion Calculator, and it said that resistor would cost 1.7 dB. 95.3 dB/W is still great.

By the way, could someone who knows more than I double-check my math? I"m really unsure of my dB calculations. Especially since I know sound pressure level and power gain are very different units, even though they're both called "dB".
 
Just as a counter point to everyone with DWs using the resistors, I tried them out and thought they sounded a little more lean with the resistors in place imo. They are relatively cheap and no doubt returnable, so not a big deal to test drive. I think it's less about the speakers and their 11 ohms than it is with the particular amp being used.
 
apholden said:
The Dirty Weekends are "only" 97 dB/W. A little less than my Soul Supremes, but still amazingly efficient. Unfortunately, they have an odd impedance, which means you'll probably need loading resistors to match them to your amplifier. If my math is right, a 25Ω loading resistor will drop the efficiency by about 1/3, but I'm not sure how many dB that will cost you.

You should still only need a few watts to raise the volume to painful levels.

How big of a room do you want to fill, and are you looking to quietly play music while the baby sleeps in the next room, or do you want to light up the strip?

As for turnaround time, that's wildly variable. I got my Soul Supremes in about 3 weeks, while others mentioned a couple months. I would bet on the longer end of that range because their supply chain is still recovering from Lockdown.
Click to expand...

Is it correct that the higher the dB/w, the less power is needed from your amp?
My current speakers are Pioneer SP-FS52s and their sensitivity is 87dB. My receiver is 20w per channel.
The main setup is in the living room and it’s not the biggest space so I don’t need the sound to be super sonic and I also don’t need it to be quiet. My daughter is almost 6 so she goes to bed at normal hours. If we ever want to listen to music after she goes to bed, we have a setup in the bedroom.

I guess I’m just trying to determine if the DWs would be a good fit. I’m looking for a second pair of speakers for the living room anyway.
 
Ginormousthumbs said:
Is it correct that the higher the dB/w, the less power is needed from your amp?
My current speakers are Pioneer SP-FS52s and their sensitivity is 87dB. My receiver is 20w per channel.
The main setup is in the living room and it’s not the biggest space so I don’t need the sound to be super sonic and I also don’t need it to be quiet. My daughter is almost 6 so she goes to bed at normal hours. If we ever want to listen to music after she goes to bed, we have a setup in the bedroom.

I guess I’m just trying to determine if the DWs would be a good fit. I’m looking for a second pair of speakers for the living room anyway.
Click to expand...

I don’t think anyone here has returned theirs. That says a lot.
 
Ginormousthumbs said:
Is it correct that the higher the dB/w, the less power is needed from your amp?
My current speakers are Pioneer SP-FS52s and their sensitivity is 87dB. My receiver is 20w per channel.
The main setup is in the living room and it’s not the biggest space so I don’t need the sound to be super sonic and I also don’t need it to be quiet. My daughter is almost 6 so she goes to bed at normal hours. If we ever want to listen to music after she goes to bed, we have a setup in the bedroom.

I guess I’m just trying to determine if the DWs would be a good fit. I’m looking for a second pair of speakers for the living room anyway.
Click to expand...
Correct. The higher the decibels per watt, the less power you'll need. Your current receiver will drive DWs no problem. You'll turn the volume knob a lot lower to get the same volume. Alternately, you can crank it and see how quickly your neighbors complain!
 
Ginormousthumbs said:
Is it correct that the higher the dB/w, the less power is needed from your amp?
My current speakers are Pioneer SP-FS52s and their sensitivity is 87dB. My receiver is 20w per channel.
The main setup is in the living room and it’s not the biggest space so I don’t need the sound to be super sonic and I also don’t need it to be quiet. My daughter is almost 6 so she goes to bed at normal hours. If we ever want to listen to music after she goes to bed, we have a setup in the bedroom.

I guess I’m just trying to determine if the DWs would be a good fit. I’m looking for a second pair of speakers for the living room anyway.
Click to expand...

20 watts is a perfect fit for the DW. You’ll actually get 15 watts into their 12 ohm load, still plenty.
 
HiFi Guy said:
20 watts is a perfect fit for the DW. You’ll actually get 15 watts into their 12 ohm load, still plenty.
Click to expand...

Awesome! So I don’t have to worry about the capacitor upgrade? Honestly don’t know what that is. Loading resistors? I won’t need the spikes as I have flooring in the living room.
I’m going to take the next week to mull it over. I just want to be prepared for 7/1.
 
The capacitors are probably down to your taste. I'm sure the stock caps sound fine.
The loading resistors are a maybe. Maybe get a set of the 25Ω resistors and try the speakers with them and without them. Then try to return them if you decide the speakers sound better without.
 
Ginormousthumbs said:
Awesome! So I don’t have to worry about the capacitor upgrade? Honestly don’t know what that is. Loading resistors? I won’t need the spikes as I have flooring in the living room.
I’m going to take the next week to mull it over. I just want to be prepared for 7/1.
Click to expand...
While I've not heard the DWs without the Clarity Cap capacitors, the best part is if you buy them without, you can still add them on your own later on with nothing more than a screwdriver. I had a conversation with someone who bought without, and then added them, and he said they did a nice job of smoothing out the top end.

If you do buy a pair, the biggest thing to remember is to play with placement. Now that I have the Souls, its even more apparent how much more directional the DWs are. Toe in almost to, or completely towards the listening position seems to be the consensus opinion, and completely agree with. Also, fiddle with how far they are off the ground, how much lean back you like, some distance from the back/side walls, etc. If you want to just plop them down and expect them to be amazing, you might be disappointed.
 
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