2. speakers
  3. 1365595555

Zu Soul Superfly 8 ohm experiment

Have been Zu owner for many years starting with Tone progressing to Druid -then Essence and now Soul with nano tech drivers. Drive the speakers with Unison Research Preludio which is a 15 watt single ended class a amp which utilizes 6 ohm output taps. After reading a review of the speakers which suggested the speakers sounded best when paired with an amp that utilizes 16 ohm output taps i posed the question to Sean. he suggested i could experiment altering the impedance of the speakers by utilizing a 16 ohm resistor to lower the impedance to 8 ohms. I have generally been happy with the sound of my system except for a bit of hardness/glare in the higher frequencies that shows up on some recordings . i attributed this to the recording technique as ell as less than optimal listening environment (10x12 room ) also wondered if perhaps the preludio was not happy with the 16 ohm impedance. Decided to give Seans' suggestion a try and purchased a pair of 15 ohm Mills resistors from parts Express. Wrapped the leads around each of the speaker terminals -placed the spade lugs of the cables over the leads and tightened down the connector. have to admit I did not expect much, but was pleasantly surprised. Thought the speakers sounded cleaner - vocals clearer and a definite decrease in the high end glare/hardness . After changing speaker cables I had been bothered by what seemed to be an exaggeration of sibilance . but noticed that it now sounded much more natural and the hardness associated with it improved. wonder if any other Zu owners have had a similar experience ?
dcr

Showing 2 responses by 213cobra

213cobra
885 posts
 
Impedance matching between amp outputs and speaker can have strong effects. Resistors are cheap and easy, but if you settle on the advantage, here's an even better way to do it:

http://anticables.com/autoformers#!/~/category/id=3461167&inview=product14644819&offset=0&sort=normal

The AntiCables autoformers for load matching do a superb job and improve dynamics over going the resistor route.

Phil
213cobra
885 posts
 
>>I looked at the anticable site, but it seemed like the autoformers were made for dividing the ohms to a smaller number...8 ohm tap on an amp to 4 ohm speakers...the issue with the super fly's is they are designed for 16 ohm taps and my amp has 8 ohm taps, in this scenario is the autoformer still an option?<<

Gauchowino,

You're right that the autoformers are intended to multiply the speaker impedance that an amp sees. But if you wire them "backwards," your amp will see 1/2 the Superfly's rated impedance. From Paul Speltz' web site FAQ:

"10) What happens if I run them backwards?

Most everybody uses the ZEROs to MULTIPLY the speaker's impedance by connect the BLACK and WHITE leads to the speaker, and connecting two of the other four leads to the amplifier. In contrast, you can use the ZEROs to DIVIDE the speaker's impedance. This can be used to optimize your speaker's impedance to the rare amplifier that prefers a low impedance speaker, like the Decware Zen tube amplifier that has only a 2 ohm output tap. This can be done by connecting the BLACK(-) and WHITE(+) leads to the AMPLIFIER, and connecting two of the other four leads to the SPEAKER.

-Divide speaker's impedance by 2 = YELLOW (+) & BLUE (-) to Speaker (ie. 8 ohm speaker becomes 4 ohms)

-Divide speaker's impedance by 3 = YELLOW (+) & BROWN (-) to Speaker

-Divide speaker's impedance by 4 = GRAY (+) & BROWN (-) to Speaker

You will notice the only thing that changed is that the connections to the speaker and to the amp are FLIP-FLOPPED...thus making it an impedance DIVIDING autoformer, instead of an impedance MULTIPLYING autoformer.

Please experiment for best sound. As your speaker's impedance is reduced, the Zen amplifier will be able to source more and more power into the speaker down to the maximum power point of 2 ohms (Zen amp). Best sound will be achieved when a balance between most power and "critically" damping the speaker is achieved. Reducing the speaker's impedance to low will under damp the drivers causing an overly blooming bass. Trust your ears, and when you achieve the best sound possible, you are done. An interesting article on critically damping your speakers can be found here: www.otlamp.com/articles/tomcik/index.html"

Phil
More to discover