Amplifier Recommendation for 2245H's?

[DerekTheGreat]

Hello everyone!

I've got a pair of B460 clones and am in need of an amplifier to drive them. I had two Crown K1's bridged, but they're both dead now. (The one started adding noise and the other still works, but at reduced output? :confused:) I'm thinking I need at least 600 watts, but would love to find something in the 800 watt or better club. Also under advisement that the K1's weren't ideal, not actually high current. That a proper amp rated at 600 watts or so could do the same job if not better. I say that because I was thinking of having the K1's repaired or purchasing two K2's. I was very happy with the K series until they started to fail me, spectacular on sub duty and the system was producing the best and most enjoyable bass I've ever experienced.. I thought and was hoping I wouldn't need the power of a K1 bridged, but with the BX63A in place I occasionally saw clip lights on them. Looks like I'm a bit of an SPL junkie after all..

Anyway, what would you fine folks recommend I drive my 2245H's with? Even though I saw Amir's review on an Emotiva XPA-DR2 (here: https://www.audiosciencereview.com/forum/index.php?threads/emotiva-xpa-dr2-review-stereo-power-amplifier.25067/) and it's distortion "spray" I'm still thinking it could be a viable solution? 550 watts a side and no fan.... What about the Crown XTI series? Thinking a 6002 looks good on paper. Came across a thread somewhere else where a fella used a 4002 bridged to run a single 2245H. Isn't bridging a bad idea in general though?

Thank you for your time,

Derek

[hjames]

I've been running my B460 with a HK Citation 22, bridged to Mono. I Think I figured that puts it somewhere near 600 watts.
Been using it for nearly 10 years overall, with full bass and no problems. (I had used it with a JBL 4641 18" sub previous to getting the B460 about 5 years ago)


Hello everyone!

I've got a pair of B460 clones and am in need of an amplifier to drive them. I had two Crown K1's bridged, but they're both dead now. (The one started adding noise and the other still works, but at reduced output? :confused:) I'm thinking I need at least 600 watts, but would love to find something in the 800 watt or better club. Also under advisement that the K1's weren't ideal, not actually high current. That a proper amp rated at 600 watts or so could do the same job if not better. I say that because I was thinking of having the K1's repaired or purchasing two K2's. I was very happy with the K series until they started to fail me, spectacular on sub duty and the system was producing the best and most enjoyable bass I've ever experienced.. I thought and was hoping I wouldn't need the power of a K1 bridged, but with the BX63A in place I occasionally saw clip lights on them. Looks like I'm a bit of an SPL junkie after all..

Anyway, what would you fine folks recommend I drive my 2245H's with? Even though I saw Amir's review on an Emotiva XPA-DR2 (here: https://www.audiosciencereview.com/forum/index.php?threads/emotiva-xpa-dr2-review-stereo-power-amplifier.25067/) and it's distortion "spray" I'm still thinking it could be a viable solution? 550 watts a side and no fan.... What about the Crown XTI series? Thinking a 6002 looks good on paper. Came across a thread somewhere else where a fella used a 4002 bridged to run a single 2245H. Isn't bridging a bad idea in general though?

Thank you for your time,

Derek

[rusty jefferson]

Hello everyone!
. ..That a proper amp rated at 600 watts or so could do the same job if not better...
That's gotta be 600 @ 8 ohms, not 4 ohms. Many amps (especially Class D) drop their impedance to 4 ohms if bridged. I have found, as a general rule, bridging amplifiers adds noise.

[christo]

What about the Crown XTI series? Thinking a 6002 looks good on paper. Came across a thread somewhere else where a fella used a 4002 bridged to run a single 2245H. Isn't bridging a bad idea in general though?

Thank you for your time,

Derek

I use a Crown XTi 4002 for my SUB18s and have used it for 2245s in my DIY 4345s works fine - more than loud enough!

Now if you could only find new Crown amps...

[rusty jefferson]

...What about the Crown XTI series? Thinking a 6002 looks good on paper. Came across a thread somewhere else where a fella used a 4002 bridged to run a single 2245H. Isn't bridging a bad idea in general though?

Thank you for your time,

Derek
https://www.audioheritage.org/vbulletin/showthread.php?28635-Crown-Xti-series

[DerekTheGreat]

Thank you for all the responses! I appreciate the input. Incase people don't want to read through my long winded reply, what about the Emotiva XPA-DR2? Tempting due me being able to purchase new and their lack of fans plus >500 watt output.


I use a Crown XTi 4002 for my SUB18s and have used it for 2245s in my DIY 4345s works fine - more than loud enough!

Now if you could only find new Crown amps...


https://www.audioheritage.org/vbulletin/showthread.php?28635-Crown-Xti-series

Hmm, mixed bag on the Xti series. Shacard wasn't happy with his Xti 1000, replaced it with a Crest 8001. Monster amp, claims to lay down 720 watts @ 8 ohms stereo. Now to find one for sale locally..

Seems Xti model numbers which don't end in "2" are made in the U.S. I'm tempted to try a Xti 4000, but those seem to have been for China only and the ones I've seen for sale aren't working correctly. So that puts me at the 6000. That thing is rated for 1200 watts into 8 ohms, but I can't find Crown's official literature for it or anything x000, only x002.. Also, how loud are the fans on the Xti series???

Looks like the x002 series are still being made, which makes the ones at the wattage point I'd need unaffordable for now. However, that Emotiva XPA-DR2 is affordable. More so to me because it's also new. I'm finally starting to get tired of buying old amps and then being disappointed by them. The only "old" amps I've purchased and owned long term and pushed to their clip limits without failure have been the Adcoms I bought. Those things have had to stand in for inferior products more than I thought they would've, despite all the hate/skepticism there is for them. (GFA-555II's)


That's gotta be 600 @ 8 ohms, not 4 ohms. Many amps (especially Class D) drop their impedance to 4 ohms if bridged. I have found, as a general rule, bridging amplifiers adds noise.

I recall our conversation on this, but I'm still struggling with it because how does the amplifier drop it's impedance? Isn't impedance dictated by the load (speaker) placed in the electrical path? That's the way I was taught to understand it, anyway. And of all the amplifiers I've looked at, I go straight for the 8 ohm ratings, bridged or stereo. When I was running my XPL's, those were 6 ohm nominal, so I just made some approximation between the 4 & 8 ohm rating of the amplifiers I was running with them.

[rusty jefferson]

...I recall our conversation on this, but I'm still struggling with it because how does the amplifier drop it's impedance? Isn't impedance dictated by the load (speaker) placed in the electrical path?...
Poor wording on my part. The amplifier impedance doesn't drop, but the impedance the amplifier needs to see to give its maximum rated output may drop when bridged. The Crown K-1 amplifiers were a good example. 350 watts per channel @ 8 ohms, 1500 watts bridged @ 4 ohms. No rating for bridged @ 8 ohms. They don't say because it may still only be 350 watts @ 8 ohms, or maybe 450. That's not going to help sell amplifiers. The K-1 also list those power numbers @ 1khz, not 20hz or 20hz-20khz.

The Emotiva doesn't look like a good full range amplifier but would probably do sub duty fine and avoid the fan....if you think it's enough power and you can run it balanced. The S/N ratio is awful running single ended. If you were clipping the K-1 @ 350 watts per, you need twice the power (700 watts) to get just 3db more SPL all things being equal, but a stouter (than the K-1) 700 watt per channel amp will likely give you more than 3db of headroom over the K-1.

[BMWCCA]

You all must play your music really loud!!

While I don't use 2245H as a sub, I do run them properly crossed-over in my 4345 clones. As I was told by my speaker's original owner, the motor for the 2245 is the same as that in the 2235 and doesn't take a lot of power to drive it. Mine are in a bi-amp system crossed at 290Hz and powered by a Crown PL-400 rated at 190 WPC at 8-ohms in stereo mode. I also have a Crown Studio Reference-II but I've never felt compelled to use it in this system because I've never seen the IOC lamps of the PS-400 ever even flicker. The Studio Reference shows a rated output of 355 watts-per-channel in stereo mode at 8-ohms.

[short_circutz2]

Hmm, mixed bag on the Xti series. Shacard wasn't happy with his Xti 1000, replaced it with a Crest 8001. Monster amp, claims to lay down 720 watts @ 8 ohms stereo. Now to find one for sale locally..Seems Xti model numbers which don't end in "2" are made in the U.S. I'm tempted to try a Xti 4000, but those seem to have been for China only and the ones I've seen for sale aren't working correctly. So that puts me at the 6000. That thing is rated for 1200 watts into 8 ohms, but I can't find Crown's official literature for it or anything x000, only x002.. Also, how loud are the fans on the Xti series???Looks like the x002 series are still being made, which makes the ones at the wattage point I'd need unaffordable for now. However, that Emotiva XPA-DR2 is affordable. More so to me because it's also new. I'm finally starting to get tired of buying old amps and then being disappointed by them. The only "old" amps I've purchased and owned long term and pushed to their clip limits without failure have been the Adcoms I bought. Those things have had to stand in for inferior products more than I thought they would've, despite all the hate/skepticism there is for them. (GFA-555II's)XTI x000 series, specifically the XTI 4000 you mention were the first series of XTI amps and WERE available in Canada and the US. I live in Canada and have an XTI 4000. We sold it new to a friend to power the subs he was using in his pa at the time when his CE2000 died. (my late father was the Soundcraft Canada dealer here for over 20 years until his passing 4 years ago), then I purchased it off the friend when he switched over to his PRX system. It has low hours on it.

[Ian Mackenzie]

You all must play your music really loud!!

While I don't use 2245H as a sub, I do run them properly crossed-over in my 4345 clones. As I was told by my speaker's original owner, the motor for the 2245 is the same as that in the 2235 and doesn't take a lot of power to drive it. Mine are in a bi-amp system crossed at 290Hz and powered by a Crown PL-400 rated at 190 WPC at 8-ohms in stereo mode. I also have a Crown Studio Reference-II but I've never felt compelled to use it in this system because I've never seen the IOC lamps of the PS-400 ever even flicker. The Studio Reference shows a rated output of 355 watts-per-channel in stereo mode at 8-ohms.

Hi Phil,

In your situation l am sure you have more than enough power. I rarely use more than 25% of my amps output for most of my listening. Those Crown amps are great btw. A love the older Crown amps.

In the case of the B460 subwoofer the bass response is boosted by 6 db (4x the power) at 26 hertz when used with the Jbl BX63 crossover it comes with to produce a flat output at full power down to 25 hertz. That needs real horsepower. I have seen a 300 watt amp shut down running a B460. It overheated. The whole room was pressurised and my jeans were resonating along with my balls …Lol.

As the crossover for the B460 is below 80 hertz all the power is focused on bass transients like bass guitar, drums, synthesiser and the like and for low frequency effects in Home Theatre use. So it’s very intense on a power amp particularly if the user likes loud bass.

From my point of view that would account for the higher amplifier power rating above.

Horses for courses.

[Ian Mackenzie]

FWlF l use a Yamaha pro power amp that l bought 10 years ago. It’s the PD7000S P model rated at 700 watts per channel into 8 ohms stereo. That’s about twice the power likely to be required for normal bi amp applications of the 4345s. It never gets stressed in my situation and l like the bass it delivers into the 2245H woofers. It’s tuneful and dynamic. I also like the connectivity options. It’s not the best or the worse amp buts it’s proven to be very reliable. Bridged it’s 1,900 watts into 8 ohms. 1,100 watts per channel stereo into 4 ohms.

https://www.crutchfield.com/S-Jafq3yTqpZQ/p_845P7000S/Yamaha-P7000S.html

Edit I never hear the fan at normal levels which is great. I dislike loud fans in a domestic situation because the system signal to noise ratio is unsatisfactory for hifi sound reproduction. The system resolution is masked by noise.

[DerekTheGreat]

Poor wording on my part. The amplifier impedance doesn't drop, but the impedance the amplifier needs to see to give its maximum rated output may drop when bridged. The Crown K-1 amplifiers were a good example. 350 watts per channel @ 8 ohms, 1500 watts bridged @ 4 ohms. No rating for bridged @ 8 ohms. They don't say because it may still only be 350 watts @ 8 ohms, or maybe 450. That's not going to help sell amplifiers. The K-1 also list those power numbers @ 1khz, not 20hz or 20hz-20khz.

The Emotiva doesn't look like a good full range amplifier but would probably do sub duty fine and avoid the fan....if you think it's enough power and you can run it balanced. The S/N ratio is awful running single ended. If you were clipping the K-1 @ 350 watts per, you need twice the power (700 watts) to get just 3db more SPL all things being equal, but a stouter (than the K-1) 700 watt per channel amp will likely give you more than 3db of headroom over the K-1.

Oh alright. But aren't amps generally more stable as you increase speaker impedance? Seems a bit fishy that something would have trouble at 8 ohms but not 4... If I can attach the spec sheet for the K series I'll try. There is a rating for 8ohms bridged but it's at 1khz, 1100 watts. So probably like 950 or so where I was using it. I really liked the K on subwoofer duty, nice & tight bass with no fan noise.

Yeah, for full range duty I think the Emotiva would be horrible. But perhaps for subwoofer duty.... However, after pulling the Furman out of my system I think I could get away with 6 or 700 watts of high current power. I'm thinking the two power conditioners in series choked current flow? I played the system last night and did not see the clip lights on the PS-200 at all. The lights flickered on the 555II, but it really seemed like it was playing louder than it was able to when hooked to the Furman.


XTI x000 series, specifically the XTI 4000 you mention were the first series of XTI amps and WERE available in Canada and the US. I live in Canada and have an XTI 4000. We sold it new to a friend to power the subs he was using in his pa at the time when his CE2000 died. (my late father was the Soundcraft Canada dealer here for over 20 years until his passing 4 years ago), then I purchased it off the friend when he switched over to his PRX system. It has low hours on it.

Hi short_circutz2, I'm sorry to hear about your father.. What would you want for the XTI 4000 and how loud is it's fan? I'd say my system runs 75% of the time at low levels. Pretty much only I and Angie can stand it when it's balls to the wall, so it mostly loafs when people are over. But any time I'm home and not running the TV, stereo is on.


Hi Phil,

In your situation l am sure you have more than enough power. I rarely use more than 25% of my amps output for most of my listening. Those Crown amps are great btw. A love the older Crown amps.

In the case of the B460 subwoofer the bass response is boosted by 6 db (4x the power) at 26 hertz when used with the Jbl BX63 crossover it comes with to produce a flat output at full power down to 25 hertz. That needs real horsepower. I have seen a 300 watt amp shut down running a B460. It overheated. The whole room was pressurised and my jeans were resonating along with my balls …Lol.

As the crossover for the B460 is below 80 hertz all the power is focused on bass transients like bass guitar, drums, synthesiser and the like and for low frequency effects in Home Theatre use. So it’s very intense on a power amp particularly if the user likes loud bass.

From my point of view that would account for the higher amplifier power rating above.

Horses for courses.

Hi Ian, you know, I am really starting to love this little PS-200! Makes me wish I ponied up for the 400, but I didn't have the peanuts to pay the elephant.. What would sound better, the 200 or 400 in my application? I'm using mine for the 813C's above 85hz. Before I got the Furman power conditioner out of my loop, I thought I'd need more juice as I saw clip lights, but that's not the case now. Although it couldn't hurt to have more juice in the tank.

Yes, with the BX63A in place that taxed the amps big time. So then I had the not so brilliant idea to pull it out in favor of the Ashly XR1000 I had, figure I got the same benefits of the BX63A but without the bass bump. Well yeah, I reduced strain on the amplifiers but I lost the bass presence and added noise to the system. BX63A is back in place for good now. That room must've been warm, my balls have yet to resonate haha. Could be because the room isn't closed off either, the one end on the far end opens up into a hall, no door.

Guess I listen really loud too. That bass impact is addictive along with the immediacy of these 813C's. I can now reproduce concert levels in my house but with audiophilic sound quality and minus all the people whose shoulders I'm not tall enough to see over or the beer they're probably going to spill all over my shoes. How does one recover from such an addiction?

[mmc8180]

Watching this thread with interest ... currently driving 4 -18" custom-built subwoofers (10 cf each, with 2-2242 and 2-2245 8 ohms), each with a QSC RMX 2450 bridged (1300 watts into 8 ohms). The sound performance is satisfying, but absolutely can't stand the fan noise. I am in the process of re-designing my entire system, and I intend on driving the subs with a 6 channel Cinepro 4k6 Gold (475 watts into 8 ohms each channel). It has a fan but is very slow speed and just cannot be heard even under load.Interested in others experience with lower wattage amps but will hang onto the 4 QSC's just in case. And if necessary, will move them to another room ...

[Ian Mackenzie]

Ah,

Reading through the above posts it has occurred to me that the actual driver impedance could be a factor.

I will have to turn on Leap to check but the impedance of the JBL 2245H in a tuned bass reflex enclosure isn’t 8 ohms. It dips down towards the dc resistance of the voice coil and is reactive. Ie not a passive resistance. That means in bridged mode you need to think about how your particular amp will cope in bridged mode.

In theory @ 600 watts the amp has to deliver 69 volts rms into an 8 ohm load. At the voltage the current is 8.7 amps. However if the load is for example 5 ohm at a frequency region of peak demand the voltage is 54 volts and the current is 11.00 amps. No matter how you look at it ohms law is hard at work here. When semi conductors are pressed reliability becomes a factor.

Under that condition the amplifier in bridged mode may or may not be adequately rated. The efficiency of the amplifier may possibly be impacted because more current is flowing at a lower voltage.

My inclination would be to buy a much more powerful power amp than the power your intended to use so the amp is not going to be operating near the worst case scenario.

[rusty jefferson]

Oh alright. But aren't amps generally more stable as you increase speaker impedance? Seems a bit fishy that something would have trouble at 8 ohms but not 4...
It depends on the amplifier. To be honest I have no idea whether the K-1 is a Class AB with a SMPS, or a Class D, Class H, or something else. It's not that Class D amplifiers (what I was referring to) become unstable into a higher impedance speaker, they just produce less power (typically) into the higher impedance.

Apologies, the spec sheet I found didn't show a rating for 8 ohms bridged, so it's probably not Class D? But if they can deliver 1100 watts @ 8ohms, a pair should be fine.

[DerekTheGreat]

Ah,

Reading through the above posts it has occurred to me that the actual driver impedance could be a factor.

I will have to turn on Leap to check but the impedance of the JBL 2245H in a tuned bass reflex enclosure isn’t 8 ohms. It dips down towards the dc resistance of the voice coil and is reactive. Ie not a passive resistance. That means in bridged mode you need to think about how your particular amp will cope in bridged mode.

In theory @ 600 watts the amp has to deliver 69 volts rms into an 8 ohm load. At the voltage the current is 8.7 amps. However if the load is for example 5 ohm at a frequency region of peak demand the voltage is 54 volts and the current is 11.00 amps. No matter how you look at it ohms law is hard at work here. When semi conductors are pressed reliability becomes a factor.

Under that condition the amplifier in bridged mode may or may not be adequately rated. The efficiency of the amplifier may possibly be impacted because more current is flowing at a lower voltage.

My inclination would be to buy a much more powerful power amp than the power your intended to use so the amp is not going to be operating near the worst case scenario.

A more powerful amp seems to be the take-away. Do you folks have any objections to running one in bridged mode? It's just that way seems like such an easy way for a guy like me with a miniscule budget to get to the goal. However, if a mono block or high power stereo amp is preferred, I will start saving more peanuts.


It depends on the amplifier. To be honest I have no idea whether the K-1 is a Class AB with a SMPS, or a Class D, Class H, or something else. It's not that Class D amplifiers (what I was referring to) become unstable into a higher impedance speaker, they just produce less power (typically) into the higher impedance.

Apologies, the spec sheet I found didn't show a rating for 8 ohms bridged, so it's probably not Class D? But if they can deliver 1100 watts @ 8ohms, a pair should be fine.

I'm not sure, why don't these companies post what class their amp is under specifications?? I don't understand the technicals and mathematics like I once did. Ever hear of Audio Control? I've got one of their C-101 equalizers from my marantz days. They're still around and making amps. They've got this RS-1000 specifically designed for subwoofer use, mono @ 1000 watts, 2/4/8 ohm or so it says: https://www.audiocontrol.com/downloads/home/current/rs-1000/rs-1000-user-manual.pdf SNR of almost 100dB..
Too pricy for me at the moment and have fans, but maybe down the road. What really makes this company great are their user manuals, there's tons of humor speckled in them. So not your typical, put you to sleep read.

[Ian Mackenzie]

In the above case l think you will find that in bridge mode @ 4 ohms are amplifier is current limited not voltage limited to manage internal power dissipation.

Looking at the normal stereo power output @4 ohms the amp is rated at 550 watts per channel. In this situation the output voltage is 47.00 volts and the current flow is 11.70 amps.

Now in theory if we look at bridge mode in an ideal world we should have 47+47 volts = 94 volts available. This would produce 2,200 watts @4 ohms. The current flow would be 23.5 amps.

However the amplifier is rated at 1550 watts into 4 ohms bridged. This means the maximum voltage available is 78.7 volts and the current flow is 19.7 amps.

What this means is that the amplifier power output in bridged mode @ 4 ohm is 29% less than what the full bridged voltage available ref 2,200 watts. The current limiting stops the last 3.8 amps flowing into the load.

While the spec sheet doesn’t list the bridge mode power output into 8 ohms on the basis of the voltage and current available into 4 ohms bridged it should be able to deliver 1400 watts @ 8 ohms where the voltage is 106 volts and a current flow 13.2 amps.

[Ian Mackenzie]

See my comments in the other thread on the real driver impedance. Think 5.8 ohms cold. More current flows. That means more current flows through the output stage and the power supply.

In the above examples l gave you can see even a powerful amp levels off into 4 ohms bridged. I would consider the K2 if you intend to use bridge mode. You really don’t want to be riding on the safe limit with those currents flowing.

[Ian Mackenzie]

One thing l should have pointed out in a domestic situation it’s the peak voltage & current into the real load. In other words the driver is not a light bulb. Just how hot it will get is more about the duty cycle of the average current flowing through the driver. At low frequencies it’s going to be demanding. The rms sine wave power is 300 watts. 600 watts program power. Efficiency is 2.1 % A pair of them in parallel will give you 600 watts continuous sine wave and 1200 watts program power. I’d be looking at the K2.

Have a look at this. They are getting good product review feedback

https://djcity.com.au/product/behringer-nx6000-power-amp-with-smart-sense/?gclid=EAIaIQobChMIxbjzibnt-wIVB2oqCh3rVA3GEAQYAyABEgJ5pfD_BwE

[Ian Mackenzie]

Failing all this discussion if you are missing 60 hertz wire them in series and plug them into the power point for comparison purposes.

The story goes someone who will remain nameless did that with a bunch of LE15’s and stood outside to see how loud it was. Needless to say it changed the way he sees the world..LoL.

[BMWCCA]

The "littlest" of the Crown Studio Reference Series amps (Studio Reference-II) is rated at 1,100 watts into an 8-ohm load. I never demand anything like that from mine but I've also never heard the fan come on—ever! It's a pretty stout amp if you like Crown and if you can find one.

[DerekTheGreat]

Thank you for the explanation, Ian. I think I follow, mostly. LoL. Are there equations I can use for future reference? Do some folks just wire their audio stuff for 220V in the states vs 120? Seems like a better way to do it, coming from a layman like myself... As it happens, I have a lead on two K2's! I will try my luck with those once again, now that I think I've got my amp failure mode identified and solved.

That Reference II looks like a nice amp, BMWCCA! There's one for sale on Audiomart right now, but a little too rich for my blood at the moment.

[BMWCCA]

That Reference II looks like a nice amp, BMWCCA! There's one for sale on Audiomart right now, but a little too rich for my blood at the moment.Yikes! $1500 and missing one knob seems a bit excessive . . . but in reality by no more than a few hundred bucks.

Mine has the incorrect (silver) knobs, is missing the rack-mount covers, and also has a few scratches (touched-up by a car guy with BMW paint) and I got it in a swap with member Sub here. But it sounds better than anything else I've ever heard.

I'd love another but, in the words of Reb Tevye, "If I were a rich man . . . Ya ba dibba dibba dibba dibba dibba dibba dum".

[Ian Mackenzie]

When l’ve woken up and had a coffee l will type up the equation.

Power in watts x the rated impedance

Therefore:

500 watts x 8 ohm = 4,000
500 watts x 4 ohm = 2,000
1,000 watts x 4 ohm = 4,000

Take the square root of the above product = volts rms
2^4,000 = 63.24 volts rms
2^2,000 = 44.72 volts rms


Power = volts x current. Power / volts = current

Therefore 500 watts / 63.24 volts = 7.9 amps
Therefore 500 watts / 44.72 volts = 11.2 amps
Therefore 1,000 watts /63.24 volts = 15.8 amps

In bridge mode both the channels are connected in series and the input signal a inverted on one channel to arrive at 2 x output voltage per channel.

In the above examples

63.24 volts x 2 = 126.5 volts squared = 16,002 / 8 ohms = 2,000 watts
63.24 volts x2. = 126.5 volts squared = 16,002 / 4 ohms = 4,000 watts
44.72 volts x 2 = 89.4 volts squared = 7,999 / 4 ohms = 2,000 watts

2,000 watts / 126.5 volts = 15.8 amps
4,000 watts / 126.6 volts = 31.6 amps

The above assumes an ideal or perfect power amplifier.

What you will find is that the bridge mode power is limited by the current available in that mode to drive the load. This is because the twice the current has to flow through each channel of the power amplifier.

The consequence of this is that the internal heat dissipation of the amplifier has also doubled. The amplifier may not let you do that so it limits the maximum current to the load.

I will check this after my morning coffee.

[DerekTheGreat]

Whoa. Might take me a second to digest all of that, but I can now reference it at will. Thank you. :)

So perhaps I shouldn't go with the K2's and just get one amplifier that can do what I need it to do without bridging? Back before they died, the Crowns never felt super hot to the touch. I could place my hand right on the heat sink and leave it there. Warm/hot, but no danger of burning myself..

[DerekTheGreat]

Yikes! $1500 and missing one knob seems a bit excessive . . . but in reality by no more than a few hundred bucks.

Mine has the incorrect (silver) knobs, is missing the rack-mount covers, and also has a few scratches (touched-up by a car guy with BMW paint) and I got it in a swap with member Sub here. But it sounds better than anything else I've ever heard.

I'd love another but, in the words of Reb Tevye, "If I were a rich man . . . Ya ba dibba dibba dibba dibba dibba dibba dum".

If I was a rich man I'd certainly try to play ball with it. Buuut I'm going to have to wait. I've got a list going and that got added to it. Someday, perhaps. :)

[rusty jefferson]

Here's a link to the data sheet power requirements for the K-series. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.crownaudio.com/en/site_elements/k-series-calculated-data&ved=2ahUKEwjpgIqw2PX7AhUkK1kFHWDgCUUQFnoECBgQAQ&usg=AOvVaw3ZmFuVQlTmhGGto3LKzdBf

You can see that running a single K-2 at (probably) 1/3 power @ 8ohms will require 4-6 amps from your electrical outlet. Running a pair of them bridged at 8ohms, 1/3 power will require 13-17 amps from your wall outlet. You mentioned your circuit is 15 amps, so you'd be starving the amplifiers the power they need before even considering the needs of the other equipment on the circuit. They'll turn on and operate, but not properly. A single K-2 would be the way to start, if you have enough electrical headroom for everything.

[DerekTheGreat]

Guess I'll just stay where I'm at until I can afford to upgrade my electrical service. What a bummer. What if went to 220V? Aren't most modern audio stuffs configurable for either 110 or 220V? The way I understand it, I'll cut my amperage needs by 1/2 if I double the voltage and that's something a bloke could do right at the electrical box...

[HCSGuy]

Guess I'll just stay where I'm at until I can afford to upgrade my electrical service. What a bummer. What if went to 220V? Aren't most modern audio stuffs configurable for either 110 or 220V? The way I understand it, I'll cut my amperage needs by 1/2 if I double the voltage and that's something a bloke could do right at the electrical box...In general, amplifiers power supplies are switchable to work on 120v U.S. or 220v European. However, 220v European is different than 240V U.S. EU is 220v above ground, while U.S. 240v is two 120v leads in opposite phase, leaving 240v between them. You cannot mix the two. However, there are some really high power amps that will do 240v AC U.S. as well - Crown I-Tech comes to mind…

[Ian Mackenzie]

More current flows in the US 120 than 240 overseas. This means thicker gauge mains wire and bigger fuses all for more bass. More expense.

Are you looking outside the box?

I imagine that two or conceivable four 2245’s per side is a more efficient way to go. This assumes you have the space for 72 cu ft if bass enclosures. Once bass gets to really loud everything shakes. So how important is an ideal sub woofer?

A Danly Pro sub is an alternative. If you have the resources a large bass horn which is directional would be effective. Steve Schell demonstrated a large bass horn with a tiny 3 watt amplifier. Very loud.

[hjames]

My friend Steve built a quad of 2245 subwoofers using the Greg Timber article and specs a few years back.
I believe he ran them with some refurbed Adcom 565 monoblocks ...

[DerekTheGreat]

In general, amplifiers power supplies are switchable to work on 120v U.S. or 220v European. However, 220v European is different than 240V U.S. EU is 220v above ground, while U.S. 240v is two 120v leads in opposite phase, leaving 240v between them. You cannot mix the two. However, there are some really high power amps that will do 240v AC U.S. as well - Crown I-Tech comes to mind…

Oh, so I wouldn't just be able to flip the switch for 220v and rock & roll? Haven't heard of the I-Tech, or maybe I have and just forgot. But if that's the only thing I can get to run on our weird 240V set-up then it's moot or I need to then have a dedicated socket just for that type of gear.


More current flows in the US 120 than 240 overseas. This means thicker gauge mains wire and bigger fuses all for more bass. More expense.

Are you looking outside the box?

I imagine that two or conceivable four 2245’s per side is a more efficient way to go. This assumes you have the space for 72 cu ft if bass enclosures. Once bass gets to really loud everything shakes. So how important is an ideal sub woofer?

A Danly Pro sub is an alternative. If you have the resources a large bass horn which is directional would be effective. Steve Schell demonstrated a large bass horn with a tiny 3 watt amplifier. Very loud.

I've got no idea. I'm trying not to think at all audio wise at the moment. She's all fine and dandy if I don't want to blow myself into the wall. Waiting for myself to grow out of this phase.

No space available in the shit shack. Everything sure shakes. I've played just the subs and it's rather.. "whoa.." ("...let's just fire those 813C's back up and pretend I didn't hear that..") So far, only one thing has fallen from it's location. Most just kind of rotate around as if somebody meddled with them. Never had that problem before. :) Angie says she can hear & feel the system from the car when she pulls up in the driveway. No visits from the police, yet. I make sure to knock my nonsense off by 10PM or so. Fortunately, my house has shoulder room from my neighbors so I'm not right on 'em.

About three months ago I'd say it wasn't important! Now I'm all, "Whoa, this is great!" and then come to find I might have issues with power delivery. Checked into Danly Pro. Guess I'd like to stay with an 18" monster for appearance purposes. That puts me in a pair of TH118XL's. Recommended amplifier for those is one capable of 1700 watts, so that's a no-go on that tiperooski. Don't even want to know what Mr. Danley wants for just one of those. Most likely too rich for my blood at the moment and for the unforeseen future. Not to mention if I'm going to get an amplifier that nutso, why not just feed it to the 2245H's?

[DerekTheGreat]

My friend Steve built a quad of 2245 subwoofers using the Greg Timber article and specs a few years back.
I believe he ran them with some refurbed Adcom 565 monoblocks ...

Oh wow, complete with the little train tracks for the speaker wires. Someone is drinking the Kool-aid :lol_fit: Stuff sure looks nice though. Probably more money there than in my entire house. LoL this is why I never compete. Because just when I start to think I've earned the warmth of the chair under my ass through all my sweat and tears, someone else comes along and eclipses me like I wasn't even there or trying.

With resources and imagination, anything is possible. However, not in my tax bracket or zipcode. I need cooler friends in which to live through vicariously.

[hjames]

Oh wow, complete with the little train tracks for the speaker wires. Someone is drinking the Kool-aid :lol_fit: Stuff sure looks nice though. Probably more money there than in my entire house. LoL this is why I never compete. Because just when I start to think I've earned the warmth of the chair under my ass through all my sweat and tears, someone else comes along and eclipses me like I wasn't even there or trying.

With resources and imagination, anything is possible. However, not in my tax bracket or zipcode. I need cooler friends in which to live through vicariously.
Well, he had a shop rebuild the Adcom Amps for him, which apparently is a thing because the caps fail and soak the circuit boards with their weepage.
He built the boxes himself, and its quite a nice looking stack.

And - the sound is pretty amazing as well, even before the Legacy speakers and Wavelet Preamp/processor arrived.

[DerekTheGreat]

Oh I don't doubt it, bet it's incredible. Seeing stuff like that and then experiencing it for the first time is akin to going from a 20" black and white console TV from the 50's to full HD on a 72" screen complete with surround sound. You just gotta stand back and be all, "Whoa.. I didn't know this was even possible." So for me, that comes up as well as the feeling of, "Hmm, yeah maybe I don't belong.."

I've heard that about the 'Coms. I popped the hoods off of mine, I didn't see any pixie juice so I'm still squeaking by with them as they are. Although I do keep trying to retire them! But every other soldier I pop into the line ends up taking shrapnel, so the old guard ends up taking guard each time that happens.