The Wards Airline Radio/Phono Console that I'm in the midst of reclaiming has got two 8" woofers, one model 2620(4 ohm tested), with ribbed paper cone, model 2620A with flat cone(4 ohm tested) and one 3.5 inch tweeter model 2621(8 ohm tested) All AlNiCo drivers. Unsure of the make of speakers, I assume they're Jensen's, due to Wards long standing use.
Anywho, the Beast, which I've dubbed the old gal, has the speakers wired all in series at a calculated 1.6 ohm impedance. I attempted a different audio path after recapping, and new tight tolerance capacitors. I tried each combination, of wiring methods, all, sounding terrible, so I ended back up at the 1.6 ohm impedance.
First impressions: At 4 ohm, single woofer, not bad. But definitely not letting the amplifier do it's work. At 4ohm Series parallel, I get the feeling that something is getting left on the floor. So back I go, to 1.6 ohms...this thing is amazing! I made an alligator clip audio out to test the different input paths and the input switch, put on a lil Buddy Holly and just sat there. In awe of the crisp, yet ultra lifelike reproductions of the human voice this thing is capable of, in fact, when "Love Me Tender" by Elvis began to play, it brought a tear to my eyes. There is soooo much emotion that comes through this magic box, that my Technic SU-900 just can't compete with.
Anywho, the Beast, which I've dubbed the old gal, has the speakers wired all in series at a calculated 1.6 ohm impedance. I attempted a different audio path after recapping, and new tight tolerance capacitors. I tried each combination, of wiring methods, all, sounding terrible, so I ended back up at the 1.6 ohm impedance.
First impressions: At 4 ohm, single woofer, not bad. But definitely not letting the amplifier do it's work. At 4ohm Series parallel, I get the feeling that something is getting left on the floor. So back I go, to 1.6 ohms...this thing is amazing! I made an alligator clip audio out to test the different input paths and the input switch, put on a lil Buddy Holly and just sat there. In awe of the crisp, yet ultra lifelike reproductions of the human voice this thing is capable of, in fact, when "Love Me Tender" by Elvis began to play, it brought a tear to my eyes. There is soooo much emotion that comes through this magic box, that my Technic SU-900 just can't compete with.
Two 4 ohm woofers in series is 8 ohms.
Two 4 ohm woofers in parallel is 2 ohms.
That picture looks like a convoluted parallel hookup to me, but it's hard to say for sure without seeing the ends of the wires.
If the woofers were in series, they'd be out of phase
I was really confused at first, because those shadows looked like additional wires.
Two 4 ohm woofers in parallel is 2 ohms.
That picture looks like a convoluted parallel hookup to me, but it's hard to say for sure without seeing the ends of the wires.
If the woofers were in series, they'd be out of phase
I was really confused at first, because those shadows looked like additional wires.
The tweeter looks to be in parallel to me with the woofer on the left, while the woofer on the right looks to be in series with the woofer-tweeter pair, but reversed in polarity. Maybe this cures the phasing issue mentioned above.
It almost looks like the tweeter-cap network is working as a low-pass filter for the woofer on the left (in a series crossover topology), with the woofer on the right running full range? Is the woofer on the right connected to the negative terminal of the amp? Is this a current source amp?
https://sound-au.com/parallel-series.htm
Due to high inductance of speaker coil, DMM is not very accurate, likely underestimating real value.
With due respect, the wiring shown in the picture is a mess.
1) if woofers show "between 3.5 and 3.7 ohm on the DMM" yes, they are nominal 4 ohm each.
2) woofers are in series so total is 8 ohm nominal, matching what schematic asks for.
* error 1:
3) as shown they are out of phase.
* error 2:
4) tweeter (with its own capacitor) is in parallel with one of the woofers, it should be in parallel with the full series woofers combinations, to match what the schematic asks for.
5) you need:
1) if woofers show "between 3.5 and 3.7 ohm on the DMM" yes, they are nominal 4 ohm each.
2) woofers are in series so total is 8 ohm nominal, matching what schematic asks for.
* error 1:
3) as shown they are out of phase.
* error 2:
4) tweeter (with its own capacitor) is in parallel with one of the woofers, it should be in parallel with the full series woofers combinations, to match what the schematic asks for.
5) you need:
They probably on purpose wired the tweeter across one woofer as a way to lower it's volume level.
Maybe , why not?
Yet schematic shows a tweeter-capacitor across the 8 ohm OT tap.
That said, and only guessing, that console was built some 60 years ago, maaayyyybeee the "Standard" model had a single speaker and a tweeter in parallel with it (with capacitor of course) and a "premium" version boasted of "look Mom!!!! : TWO woofers!!!"
Again, only thinking aloud, and it´s also possible that "premium" version was wired as you imagine.
Old consoles/grammophones were weird as you well know
Yet schematic shows a tweeter-capacitor across the 8 ohm OT tap.
That said, and only guessing, that console was built some 60 years ago, maaayyyybeee the "Standard" model had a single speaker and a tweeter in parallel with it (with capacitor of course) and a "premium" version boasted of "look Mom!!!! : TWO woofers!!!"
Again, only thinking aloud, and it´s also possible that "premium" version was wired as you imagine.
Old consoles/grammophones were weird as you well know