JBL 2225 J or H

[rooferben]

I have a pair of ALTEC 815A cabs that I would like to put a pair of JBL 2225's in them. I will be pushing them with a 75 watt mono tube amp. Do I want the 2225H (8 ohm) or 2225J (16 0hm).

[spkrman57]

If you are using a tube amp with multiple impedance options, then I would follow what taps are available.

You did not list the desired application, ie: home use or commercial(PA) duty. Are you able to source either impedance 2205's, if so I would go with 16 ohm, but I can't say there is much difference except in my feeble mind. I think the damping might be better with 16 ohms....

I'm just one opinion here, I hope others will chime in also!

Ron sends...

[rooferben]

The 815A's have two 15's per cab. My amp has 8 or 16 ohm taps. And yes they are for home use.

[Eaulive]

I will be pushing them with a 75 watt mono tube amp. Do I want the 2225H (8 ohm) or 2225J (16 0hm)?
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The 815A's have two 15's per cab. My amp has 8 or 16 ohm taps. And yes they are for home use.

Don't seems like you have much of a choice to run them in series...

[speakerdave]

Don't seems like you have much of a choice to run them in series...

:blink:

[Eaulive]

:blink:

If he only has taps at 8 and 16 ohms on his mono amplifier and wants to connect two cabinets that has two 2225 in each, that makes four drivers.

Even with the 2225J at 16 ohms, four of those in parallel results in a total impedance of 4 ohms.

So I repeat, he's gonna have to wire something in series somewhere. If not, my teacher lied to me many years ago when he taught me the work of Georg.
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Or maybe it's my sentence you don't get... I should have say "It seems like you don't have much of a choice to run them in series..."

It was a brain fart, sorry :uhmmmm:

[speakerdave]

Well, the OP needs to clarify a number of things.

[cosmos]

Ok, I am now confused as well. I'd guess the OP means he is going to run a pair of 815A cabinets with a PAIR of 75 watt monoblocks meaning two 2225 per channel...

If so, I personally would go 16 ohm as (2) 16 ohm in parallel makes a 8 ohm load on the amp. I'd rather run a pair in parallel than (2) 8 ohm in series making a 16 ohm load on the amp.

However, if you are thinking that you may resell them, I'd go 8 ohm and wire them in series anyway. I'd guess it easier to sell 8 ohm drivers than 16...

If that is not what the OP meant then oh hell...:blink:

[rooferben]

COSMOS, you got it. I will drive the two 15's that are in one 815a cab with a 75 watt mono tube amp. The amp has 8 and 16 ohm. taps. Can you please explain to me the differants between ( in parallel ) and ( in series ).

[Eaulive]

COSMOS, you got it. I will drive the two 15's that are in one 815a cab with a 75 watt mono tube amp. The amp has 8 and 16 ohm. taps. Can you please explain to me the differants between ( in parallel ) and ( in series ).

Then as you wish, either two J in parallel for the 8 ohms tap or two H in series for the 16 ohms tap.

http://en.wikipedia.org/wiki/Series_and_parallel_circuits

[Ruediger]

When You wire two or more drivers in series the drivers will not see the low output impedance of the amplifier but rather that impedance in series with the DC resistance of the other drivers. This messes up the driver's Qt.

Ruediger

[Eaulive]

When You wire two or more drivers in series the drivers will not see the low output impedance of the amplifier but rather that impedance in series with the DC resistance of the other drivers. This messes up the driver's Qt.

Ruediger

True, but on a source that has a low damping factor, (like a tube amp's output xformer) this gets less relevant and when you have two drivers in parallel on that kind of source, each driver's back EMF screws up the other driver's Qt anyways so... :D

[speakerdave]

I appreciate the highly technical discussion, but am unable to semanticize in this context "messes up" and "screws up."

[Ruediger]

Hi Speakerdave,

Qt is one of the Thiele Small parameters. It depends on the loudspeaker's Qe and Qm, the DC resistance of loudspeaker, crossover and cables, and the amplifier's output impedance.

If You use a poor inductor in the crossover, cables with a tiny cross section, or an amplifier with a high output impedance then this will convert Your 2226 (for example) JBL jewel into a crappy driver. The Qt will be significantly higher.

The result will be an underdamped "boom box".

Ruediger

[Eaulive]

I appreciate the highly technical discussion, but am unable to semanticize in this context "messes up" and "screws up."

You rather talk about speakers being "pushed" by amplifiers? :D

[speakerdave]

It seems to me running woofers in parallel is common practice. I've driven my biamped WTW 1400nd's in parallel and also with each having its own channel of a solid state power amp, (your worst case scenario?), and I don't hear much difference if any, which I attribute to slightly greater distortion at lower impedance, until the amplifier is overtaxed. I don't recall JBL ever issuing a technical note advising against paralleling 2226's or any of its other woofers. Is there one? Although in Option C the wiring schemes for the M9500 does allow for powering each woofer with its own amp. But I should think that was a way of getting adequate power to the woofers. They do take a bit of juice.

[Eaulive]

It seems to me running woofers in parallel is common practice. I've driven my biamped WTW 1400nd's in parallel and also with each having its own channel of a solid state power amp, (your worst case scenario?), and I don't hear much difference if any, which I attribute to slightly greater distortion at lower impedance, until the amplifier is overtaxed. I don't recall JBL ever issuing a technical note advising against paralleling 2226's or any of its other woofers. Is there one? Although in Option C the wiring schemes for the M9500 does allow for powering each woofer with its own amp. But I should think that was a way of getting adequate power to the woofers. They do take a bit of juice.

I'm not sure if you're replying to somebody specific since you don't use quotes.

If it's to me then, yes, running woofers in parallel is very common practice and there's no technical note from JBL against it.

Either way I fail to see your point so I will answer with the same :blink: as in your first post.

[speakerdave]

. . . .Either way I fail to see your point . . . .

OK

[cosmos]

COSMOS, you got it. I will drive the two 15's that are in one 815a cab with a 75 watt mono tube amp. The amp has 8 and 16 ohm. taps. Can you please explain to me the differants between ( in parallel ) and ( in series ).

Ben,

In your box, I think you'll see a yellow and a green wire... Hooking the drivers in Parallel means to hook the red terminal of both drivers to the same color wire and both black terminals of both drivers to the opposite color wire.

Conversely, if you wanted to hook them in series, you would hook one color wire to the red terminal of the first driver, use another wire (not already in the box) to connect the black terminal of the first driver to the red terminal of the second driver and the opposite color wire in the box to the black terminal on the second driver.

Personally, I would choose 16 ohm drivers and hook them in parallel. This would create a nominal 8 ohm load. You would connect each cabinet to the appropriate amplifier's 8 ohm tap... If you have a volt/ohmeter, you can check the resultant resistance prior to hooking it up to the amp...

[Ruediger]

It seems to me running woofers in parallel is common practice. I've driven my biamped WTW 1400nd's in parallel and also with each having its own channel of a solid state power amp, (your worst case scenario?), and I don't hear much difference if any, which I attribute to slightly greater distortion at lower impedance, until the amplifier is overtaxed. I don't recall JBL ever issuing a technical note advising against paralleling 2226's or any of its other woofers. Is there one? Although in Option C the wiring schemes for the M9500 does allow for powering each woofer with its own amp. But I should think that was a way of getting adequate power to the woofers. They do take a bit of juice.

Hi Speakerdave,

running the speakers in parallel is okay, running them in series is not okay, that was the statement.

Ruediger

[speakerdave]

I brought in another amp and now have a channel of amplification for each woofer. The sound seems cleaner, more full, tighter. Possibly the reason is that a pair of 1400nd's, with the resistors parallel to lower the resonance impedance rise, drop below 4 ohms in part of its range. Anyway, the sound is better even at low spl.