JBL 4343 min Impedance?

[Mikhail]

Welcome all!
What is the minimum impedance in 4343 with Alnico?
2231A - What is the minimum impedance?

[Horn Fanatic]

Welcome all!
What is the minimum impedance in 4343 with Alnico?
2231A - What is the minimum impedance?

The nominal impedance listed for the 4343B is 8 ohms. Keep in mind, the nominal impedance of a transducer is derived from using a fixed frequency, usually 1K. The nominal impedance is not the D.C. resistance of the voice coil, which typically reads lower than the nominal impedance. Impedance is frequency dependent, whereas the D.C. resistance of the voice coil is not.

As for the ALNICO question, I know of no difference between ALNICO or ceramic magnet structures. The nominal impedance for the 2231A is 8 ohms, but the DCR could be between approximately 6 to 7 ohms. FYI - A typical cone loud speaker can reach an impedance of 400 ohms, then drop off at 6dB per octave based on the limitations of the voice coil.

H.F.

[Mikhail]

In this regard, the best way to connect to the output amplifier 4Om or 8Om?

[remusr]

Per JBL original spec sheet: Min 7.3 ohms at 213Hz. Nominal impedance 8 ohms. DCR 6.39 ohms.

A 40-80m run is pretty long, you may affect your amp's ability to control the woofer as the wire impedance becomes significant cw the speaker impedance. An accepted guideline is that the wire impedance should not exceed 5% of the entire circuit.

Here's an old rule of thumb that stops a bit short of your run lengths:
"According to the table for two conductor copper wire given in former Director of Acoustic Research for McIntosh Labs (and the originator of McIntosh loudspeakers) Roger Russell's online article "Speaker Wire, A History" (http://www.roger-russell.com/wire/wire.htm), 18 AWG is satisfactory for maximum length runs of 32 feet (10m) when connecting eight-ohm speakers. The maximum length for 16 AWG wire is 48 feet (15m) and for 12 AWG speaker wires the maximum length is 120 feet (36m). Halve those distances if you are using four-ohm speakers."

And Wikipedia has similar numbers: http://en.wikipedia.org/wiki/Speaker_wire#Resistance ...(see excerpt below)
Wire gauge
Thicker wires reduce resistance. The resistance of 16-gauge (http://en.wikipedia.org/wiki/American_wire_gauge) or heavier speaker connection cable has no detectable effect in runs of 50 feet (15 meters) or less in standard domestic loudspeaker connections for a typical 8 ohm speaker.[4] (http://en.wikipedia.org/wiki/Speaker_wire#cite_note-Russell-4) As speaker impedance drops, lower gauge (heavier) wire is needed to prevent degradation to damping factor (http://en.wikipedia.org/wiki/Damping_factor) – a measure of the amplifier's control over the position of the voice coil.
Insulation thickness or type also has no audible effect as long as the insulation is of good quality and does not chemically react with the wire itself (poor-quality insulation has occasionally been found to accelerate oxidation of the copper conductor, increasing resistance over time).[citation needed (http://en.wikipedia.org/wiki/Wikipedia:Citation_needed)] High-power in-car audio systems using 2-ohm speaker circuits require thicker wire than 4 to 8-ohm home audio applications.
Most consumer applications use two conductor wire. A common rule of thumb is that the resistance of the speaker wire should not exceed 5% of the rated impedance of the system. The table below shows recommended lengths based on this guideline:


Wire size
2 Ω load
4 Ω load
6 Ω load
8 Ω load


22 AWG (0.326 mm2)
3 ft (0.9 m)
6 ft (1.8 m)
9 ft (2.7 m)
12 ft (3.6 m)


20 AWG (0.518 mm2)
5 ft (1.5 m)
10 ft (3 m)
15 ft (4.5 m)
20 ft (6 m)


18 AWG (0.823 mm2)
8 ft (2.4 m)
16 ft (4.9 m)
24 ft (7.3 m)
32 ft (9.7 m)


16 AWG (1.31 mm2)
12 ft (3.6 m)
24 ft (7.3 m)
36 ft (11 m)
48 ft (15 m)


14 AWG (2.08 mm2)
20 ft (6.1 m)
40 ft (12 m)
60 ft (18 m)*
80 ft (24 m)*


12 AWG (3.31 mm2)
30 ft (9.1 m)
60 ft (18 m)*
90 ft (27 m)*
120 ft (36 m)*


10 AWG (5.26 mm2)
50 ft (15 m)
100 ft (30 m)*
150 ft (46 m)*
200 ft (61 m)*


* While in theory heavier wire can have longer runs, recommended household audio lengths should not exceed 50 feet (15 m).[4] (http://en.wikipedia.org/wiki/Speaker_wire#cite_note-Russell-4)
The gauge numbers in SWG (standard wire gauge (http://en.wikipedia.org/wiki/Standard_wire_gauge)) and AWG (American wire gauge (http://en.wikipedia.org/wiki/American_wire_gauge)) reduce as the wire gets larger. Sizing in square millimeters is also common outside of the US. Suppliers and manufacturers often specify their cable in strand count. A 189 strand count wire has a cross-sectional area of 1.5 mm2 which equates to 126.7 strands per mm

Finally, you can calculate your minimum wire size using a commonly recommended minimum damping factor of 20 for a speaker load. Most transistor amps have a damping factor of about 200 at a load impedance of 8 ohms so using that (check and substitute your amp's specs - note that most tube amps have a 10-20 damping factor so may not be able to run that far!) we calculate an amp output impedance of 8/200=0.04 ohms. For the minimum final damping factor of 20, our max source impedance is 8 / 20 = 0.4 ohms; then subtracting our 0.04 ohms amp impedance we can add up to 0.4-0.04=0.36 ohms with the wire and still have an overall 20 damping factor.
For a 40m run you have 2 wires to each speaker so total 80m wire in each circuit.
- 80m (262ft) of 8 gauge copper at 0.00063 ohm/ft = 0.165 ohms. No problem.
- 80m of 10 gauge copper at 0.0010 ohm/ft = 0.26 ohms, still ok.
- 80m of 12 gauge at 0.0016 = 0.42 ohms, too high. So min 10 gauge for a 40m run. Same conclusion as above tables.
Similarly for a 80m run total wire length of 160m, wire resistance for 8/10g is 0.33/0.52 ohms so gotta go with 8.
Good luck and hope you don't get any antennae effects.

[Mikhail]

Thank you for such a detailed and extensive answer!
I wanted to know how it would be better to connect to my amplifier output terminals 4Om or 8Om with JBL4343?

[remusr]

What you are asking?
If you are asking if a shorter 40m hookup is better than a longer 80m one, my answer would be the shorter the better.

[10 Watt Street]

He is asking 4-Ohm or 8-Ohm output connection tap on his amp.

I would suggest trying both, you can't hurt anything. On the surface, 8-Ohms looks correct.

"What you are asking?
If you are asking if a shorter 40m hookup is better than a longer 80m one, my answer would be the shorter the better."[/QUOTE]

[Mikhail]

Connect now to 8Om, and to connect to 4Om, I will need to solder, which means going to the repairman.
Here's a tube amp mono blocks: Luxman MB88 Specification of LUXMAN MB88 Luxman (http://www.audio-heritage.jp/LUXMAN/amp/mb88.html):

64081

[grumpy]

pretty things, indeed.

[Mikhail]

[QUOTE = [/ QUOTE]

Thank U!
Several years of work ... for a hobby! :)

[Mikhail]

Per JBL original spec sheet: Min 7.3 ohms at 213Hz. Nominal impedance 8 ohms. DCR 6.39 ohms.

A 40-80m run is pretty long, you may affect your amp's ability to control the woofer as the wire impedance becomes significant cw the speaker impedance. An accepted guideline is that the wire impedance should not exceed 5% of the entire circuit.

Here's an old rule of thumb that stops a bit short of your run lengths:
"According to the table for two conductor copper wire given in former Director of Acoustic Research for McIntosh Labs (and the originator of McIntosh loudspeakers) Roger Russell's online article "Speaker Wire, A History" (http://www.roger-russell.com/wire/wire.htm), 18 AWG is satisfactory for maximum length runs of 32 feet (10m) when connecting eight-ohm speakers. The maximum length for 16 AWG wire is 48 feet (15m) and for 12 AWG speaker wires the maximum length is 120 feet (36m). Halve those distances if you are using four-ohm speakers."

And Wikipedia has similar numbers: http://en.wikipedia.org/wiki/Speaker_wire#Resistance ...(see excerpt below)
Wire gauge
Thicker wires reduce resistance. The resistance of 16-gauge (http://en.wikipedia.org/wiki/American_wire_gauge) or heavier speaker connection cable has no detectable effect in runs of 50 feet (15 meters) or less in standard domestic loudspeaker connections for a typical 8 ohm speaker.[4] (http://en.wikipedia.org/wiki/Speaker_wire#cite_note-Russell-4) As speaker impedance drops, lower gauge (heavier) wire is needed to prevent degradation to damping factor (http://en.wikipedia.org/wiki/Damping_factor) – a measure of the amplifier's control over the position of the voice coil.
Insulation thickness or type also has no audible effect as long as the insulation is of good quality and does not chemically react with the wire itself (poor-quality insulation has occasionally been found to accelerate oxidation of the copper conductor, increasing resistance over time).[citation needed (http://en.wikipedia.org/wiki/Wikipedia:Citation_needed)] High-power in-car audio systems using 2-ohm speaker circuits require thicker wire than 4 to 8-ohm home audio applications.
Most consumer applications use two conductor wire. A common rule of thumb is that the resistance of the speaker wire should not exceed 5% of the rated impedance of the system. The table below shows recommended lengths based on this guideline:


Wire size
2 Ω load
4 Ω load
6 Ω load
8 Ω load


22 AWG (0.326 mm2)
3 ft (0.9 m)
6 ft (1.8 m)
9 ft (2.7 m)
12 ft (3.6 m)


20 AWG (0.518 mm2)
5 ft (1.5 m)
10 ft (3 m)
15 ft (4.5 m)
20 ft (6 m)


18 AWG (0.823 mm2)
8 ft (2.4 m)
16 ft (4.9 m)
24 ft (7.3 m)
32 ft (9.7 m)


16 AWG (1.31 mm2)
12 ft (3.6 m)
24 ft (7.3 m)
36 ft (11 m)
48 ft (15 m)


14 AWG (2.08 mm2)
20 ft (6.1 m)
40 ft (12 m)
60 ft (18 m)*
80 ft (24 m)*


12 AWG (3.31 mm2)
30 ft (9.1 m)
60 ft (18 m)*
90 ft (27 m)*
120 ft (36 m)*


10 AWG (5.26 mm2)
50 ft (15 m)
100 ft (30 m)*
150 ft (46 m)*
200 ft (61 m)*


* While in theory heavier wire can have longer runs, recommended household audio lengths should not exceed 50 feet (15 m).[4] (http://en.wikipedia.org/wiki/Speaker_wire#cite_note-Russell-4)
The gauge numbers in SWG (standard wire gauge (http://en.wikipedia.org/wiki/Standard_wire_gauge)) and AWG (American wire gauge (http://en.wikipedia.org/wiki/American_wire_gauge)) reduce as the wire gets larger. Sizing in square millimeters is also common outside of the US. Suppliers and manufacturers often specify their cable in strand count. A 189 strand count wire has a cross-sectional area of 1.5 mm2 which equates to 126.7 strands per mm

Finally, you can calculate your minimum wire size using a commonly recommended minimum damping factor of 20 for a speaker load. Most transistor amps have a damping factor of about 200 at a load impedance of 8 ohms so using that (check and substitute your amp's specs - note that most tube amps have a 10-20 damping factor so may not be able to run that far!) we calculate an amp output impedance of 8/200=0.04 ohms. For the minimum final damping factor of 20, our max source impedance is 8 / 20 = 0.4 ohms; then subtracting our 0.04 ohms amp impedance we can add up to 0.4-0.04=0.36 ohms with the wire and still have an overall 20 damping factor.
For a 40m run you have 2 wires to each speaker so total 80m wire in each circuit.
- 80m (262ft) of 8 gauge copper at 0.00063 ohm/ft = 0.165 ohms. No problem.
- 80m of 10 gauge copper at 0.0010 ohm/ft = 0.26 ohms, still ok.
- 80m of 12 gauge at 0.0016 = 0.42 ohms, too high. So min 10 gauge for a 40m run. Same conclusion as above tables.
Similarly for a 80m run total wire length of 160m, wire resistance for 8/10g is 0.33/0.52 ohms so gotta go with 8.
Good luck and hope you don't get any antennae effects.

And let's look at a specific example with my amp: Specification of LUXMAN MB88 Luxman (http://www.audio-heritage.jp/LUXMAN/amp/mb88.html) and my speakers JBL4343. I connect the speakers to the terminals of the amplifier 4, what do you think? It will be better to make a sound?

[remusr]

I would expect the 8 Ohm tap as the speakers are nominal 8. You can try for awhile then switch to the 4 tap to test of course. I'd expect 8 to have better impedance match.
Sorry about the long response earlier. I read your text as 40 m or 80 m lengths. Not 4 Ohms etc.

[Mikhail]

I would expect the 8 Ohm tap as the speakers are nominal 8. You can try for awhile then switch to the 4 tap to test of course. I'd expect 8 to have better impedance match.
Sorry about the long response earlier. I read your text as 40 m or 80 m lengths. Not 4 Ohms etc.

I quickly switch impedance can not, only by soldering, on the question of how to solder a wire to the output of 4Om or 8Om?

[audiomagnate]

I quickly switch impedance can not, only by soldering, on the question of how to solder a wire to the output of 4Om or 8Om?

Are the outputs of the amps modded? If not, just connect to pin 2 instead of pin 3. No soldering required.

[rusty jefferson]

I would expect the 8 Ohm tap as the speakers are nominal 8. You can try for awhile then switch to the 4 tap to test of course. I'd expect 8 to have better impedance match.......

I don't know if this would hold true. I know some pro speakers are designed specifically for use with low output impedance amplifiers (i.e. generally speaking, solid state). I know this is the case with the UREI monitors, but don't know about the other pro control monitors (43xx). I had a difficult time finding a tube amp that worked well with UREIs until I tried one that has an output impedance under 2ohms. I think it would be worth trying the 4ohm tap even though it involves soldering.

Anyone with knowledge of this model and crossover have thoughts?

[audiomagnate]

I don't know if this would hold true. I know some pro speakers are designed specifically for use with low output impedance amplifiers (i.e. generally speaking, solid state). I know this is the case with the UREI monitors, but don't know about the other pro control monitors (43xx). I had a difficult time finding a tube amp that worked well with UREIs until I tried one that has an output impedance under 2ohms. I think it would be worth trying the 4ohm tap even though it involves soldering.

Anyone with knowledge of this model and crossover have thoughts?

I think he's already got them hooked up to the four ohm tap. No anything required for that suggestion.

[Mikhail]

Are the outputs of the amps modded? If not, just connect to pin 2 instead of pin 3. No soldering required.

In my case, simply can not be connected. Such a device amplifier. The photo shows a native connection 4-pin:
I do not have a native plug. On the other side of the amplifier previous owner installed ordinary terminals which is soldered to the output 8Om:
According to this soldering. Only solder. By this I interested in whether 4Om is better?

[remusr]

I know little about tube amps but doesn't a source transfer power most efficiently when load impedance = output impedance, but for audio use the load impedance should be higher than the amp's output impedance for the amp to control it? To couple and to damp loudspeaker voice coil feedback? So the 4ohm tap may not give as much power but would give better fidelity for speakers with a min impedance of 7.3 ohms and a nominal impedance of 8 ohms. Right?
I am having problems with my Japanese today so couldn't read the linked MB88 specs. I'm with Rusty - there must be someone experienced with this old amp! Maybe not on this forum but on vintage tube sites?

[Mikhail]

Per JBL original spec sheet: Min 7.3 ohms at 213Hz. Nominal impedance 8 ohms. DCR 6.39 ohms.

What does it mean: DCR 6.39 ohms?

[martin2395]

It is the resistance of the coil when meausred with a multimeter.

[Mikhail]

It is the resistance of the coil when meausred with a multimeter.
Thanks

[remusr]

What he said. Direct Current Resistance as you measure with a multimeter. Not same as impedance which includes capacitance and inductance effects and varies with frequency.