16 ohm speakers: any amp sounds better with more resolution. speaker cables less critical.


First,
  
Thanks to anyone who responds with whatever answers/opinions/advice comes from this. I'm retired, covid bound, Donna is taking care of everything holiday related, too much time, always curious.
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I happened across this in an old thread started by Ralph (atmasphere)

"Sixteen ohms, BTW is a very simple means for getting more resolution out of your system, as nearly every amplifier made sounds better on 16 ohms than it will on 4 or 8 ohms. Speaker cables become far less critical too."

My speakers are 16 ohms (Electrovoice horn tweeter, horn mid, 15" woofer, crossover, rheostats, from 1958).
Extremely efficient, I have more than enough power. Amp, now and in the past all had 16 ohm taps.
Of course I can hook them up to my Cayin's 8 ohm taps now and listen, but facts, opinions, advice, to learn is good.
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Lots of Questions? 

1. why/how do 16 ohm speakers make amps sound better, with more resolution? 

2. why speaker cables less critical? perhaps this is why I/we don't hear cable differences in my system?
I'm using my homemade twisted pair of cat 5 now (8 individually insulated small diameter solid core).

3.  to get exterior bias control: use 8 ohm tap for my 16 ohm speakers? (get alternate amp 4/8 no 16 tap,)

lose advantage(s)? 'sounds better'; 'more resolution'; 'speaker cables less critical'? 

this says slightly more mids:

http://blog.hughes-and-kettner.com/ohm-cooking-101-understanding-amps-speakers-and-impedance/

I can fine tune my speakers via their two rheostats: 'presence' and 'brilliance', so not really an issue for me.

4. Importance of Bias Control

how important is Bias? (I don't care about heat, power output, or tube life, just as bias affects sound). Frankly, using vintage tube receiver Fisher 500C, 800C and Fisher Mono Blocks 80Z, I have never checked or adjusted bias. I just put the control in the center position when cleaning insides/controls.

I have always used 16 ohm taps of various vintage tube and SS amps and newer current tube Cayin A88T. (original version, the only one with 16 ohm taps). It's bias control is internal, versions with safer external bias do not have 16 ohm taps.

5. replace their two rheostats? ('presence' and 'brilliance': copper wire-wound on ceramic body, mid/neutral position).
I have them in neutral position now, l/r frequency response equal.   

do I need to keep rheostats 16 ohms? use 8 ohm rheostat with 16 ohm drivers?

sales sheet says 16 ohm, but data sheet shows range 1.0 to 5k ohms. 

https://www.mouser.com/datasheet/2/303/controls_rheostats-1228697.pdf

does that mean, the drivers will draw whatever they draw (varies thru frequency range anyway), doesn't matter as long as rheostat range starts 1.0 ohm, extends past say 100.0 ohms?

https://www.mouser.com/datasheet/2/303/controls_rheostats-1228697.pdf

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thanks, Elliott











elliottbnewcombjr

boothroyd

Yes, I will be watching Steve, then do it myself after that.

I dug out my Multimeter, took apart, cleaned it up with contact cleaner  .. fresh batteries, and realized, I have no idea how to use it.

Tandy, Micronta, 1990, I found the manual in my fat 'instructions' folder. You know I like Vintage stuff.

What holes do I plug the cables in? What big center wheel setting? What adjust little pot to? I'm bringing it with me to Steve's.
Elliott - The multimeter will be set to Volts DC.

Things are really well laid out internally and easy to see with the bottom cover removed. The speakers should be connected (fairly certain 16 ohm taps are fine) and unit powered up while resting on its side which is quite easily supported by the structure.

The multimeter’s ground lead is attached to the (-) negative speaker post of either channel to check the 2 respective output tubes (one of which has an Orange wire and the other with a Blue wire) associated with that channel. The reason I mention the Orange & Blue wire associated with each power tube socket is because that is where the multimeter’s positive lead will be attached for checking bias. Adjacent to each pair of output tubes is a small bias board with an evident blue plastic insulated bias pot for each power tube. As I recall, Steve said ~ 40millivolts is the optimal adjustment.

Final adjustments are done once the unit has been powered up for at least 30 minutes for things to stabilize.

The more we know and understand our equipment, the more we enjoy it!


boothroyd

thanks

I was going to hook up my shop speakers, they are small 8 ohm, does it matter? is any load good enough?

or, I avoid carrying the 55lb beast, just disconnect inputs, flip it on it's back, have at it.

I've seen inside, took the cover off the hour I received it. Very impressive, and very spacious, easy to reach the contact points and adjusters.

plangco here posted:

1. set his multi to 20V (as a preliminary setting, just to be in that range?; says spec is .4, he uses .35 to get longer tube life and slightly warmer sound.

.4 what? how is .4 equal to 40 millivolts?

is he saying start at 20, then increase to 20.4 or 20.35?

I need brain surgery as previously discussed!
@clio09 , Hi clio, I wanted better dispersion so that everyone seated on the sofa (watching movies) would have the same frequency balance. I am sure the Sound Labs will suit that purpose. ESLs are very simple devices. I suspect if there is going to be any change in sound quality it will be in the design of the interface which in the case of the Sound Labs has been upgraded on several occasions. Like any ESL they need the right amp to sing and I know I have a pair that suit wonderfully. We shall see.