Minimum wattage for the RF 7 II's or III's ?

[82 Cornwalls]

6 hours ago, MicroMara said:

There are three ways to connect speakers together: Parallel connection, series connection or the combination of both. If the loudspeakers are connected via a crossover, the load of the crossover apply. So what shell be the sense of your posts if you´know everything so well ? And yes I got tube amps at home . Kindly finish any reply now ! I´m no longer willing to communicate at this level.

 

To clarify a little more, drivers were Visaton B200, no filter/crossover.

 

Reader has never experienced tube amps, reads MicroMara's statements "maybe some tube amps can´t handle these impedance dips." and "a powerfull push and pull or single ended tube amp (  for example 20 W / 8 ohm ) can handle the impedance dips without any problems , may a tube amp with 3 to 5 watt can get problems. These will shut off on higher volume levels." and decides against trying a tube amp. ☹️

 

Any tube amp (worth having) will play the RF-7s and just like solid state amps, some may be better than others, but tube amps can handle the impedance dips and low power amps won't shut down.

 

I don't always crusade for tube amps, but once in a while I get in a mood when I see statements that are misleading. Differences of opinion are everywhere in audio, I like for people to make up their own minds from their experience or at least factual information, not conjecture.

[82 Cornwalls]

23 minutes ago, stormin said:

I'll stick with my 1200 wpc @8ohms / 1600 wpc @4ohms ss monoblocs. What dips? 😁

 

That should do.

Is it rated for 2 ohm power?

Any tests showing 2 ohm output?

 

I have a 100 watt ss amp that doesn't care, it keeps increasing output down to 2 ohms (over 300w) and is rated for 1.5 ohms (it also drove the 4 fullrange 6 ohm drivers in parallel).

 

As mentioned above, tube amps can be the same, just match OPTs to tube and speakers used. 

[stormin]

1 hour ago, 82 Cornwalls said:

 

That should do.

Is it rated for 2 ohm power?

Any tests showing 2 ohm output?

 

I have a 100 watt ss amp that doesn't care, it keeps increasing output down to 2 ohms (over 300w) and is rated for 1.5 ohms (it also drove the 4 fullrange 6 ohm drivers in parallel).

 

As mentioned above, tube amps can be the same, just match OPTs to tube and speakers used. 

Well I have ran 4 ohm Cerwin Vega DX 9s that dip into the 2 ohm territory without any hiccups. Actually they don't even break a sweat. But what they do for the Chorus II's at low to medium volume is just unbelievable. So much realism throughout the audio spectrum. But when you decide to crack the throttle I am front row at the event. 👍

[JefDC]

On 4/17/2023 at 10:33 PM, MicroMara said:

The RB-1582 MK II  has 200W/8Ohm per channel, purely mathematically that should be about 275 watts at 4 ohms.

What are the mathematics to arrive at 275 watts at 4 Ohm ?

[Zen Traveler]

17 hours ago, MicroMara said:

The RF 7 MK II has impedances below 4 Ohms as you can see here

 

Fwiw, I would think that is why Klipsch doesn't label it 8 Ohm as they do the Heritage line which doesnt have such a jagged Frequency Respose chart...That's why the marketing term " 8 Ohm Compatible" because at higher SPL the speaker could struggle if enough current wasn't available. That's my take and still think by European standards the RF-7 can't be labeled "8 Ohm." 

[billybob]

Sure the minimum could be lower but, safely with 50 SS watts, as long as not overdriven. Of course, speaking of well made amps.

[MicroMara]

1 hour ago, JefDC said:

What are the mathematics to arrive at 275 watts at 4 Ohm ?

I´m not your math teacher 😂 I´m just a silly german guy ..and I don´t know wether you´ll understand this 🤔

 

The general formula of electric power is   

 

The following formulas apply to ohmic resistors in a DC circuit:

 

 

What is the unit of electric power? The unit of electrical power is watts:  

 

What does electrical power say? The electrical power makes a statement about how much electrical energy per time an energy converter ("consumtion") converts into other forms of energy.

 

The greater the power, the more energy is converted or transformed in a shorter time.

 

Got it 🤣

 

[82 Cornwalls]

2 hours ago, JefDC said:

What are the mathematics to arrive at 275 watts at 4 Ohm ?

 

Interesting that Rotel doesn't provide a 4 ohm or even a 6 ohm spec.

 

I would think it to be 400 watts mathematically (if the power supply was capable; none are), but in reality it could be anywhere from less than 200w to almost 400w.

 

I like to see at least 50% more power into 4 ohms vs 8 ohms with class ab amps.

[OO1]

On 4/17/2023 at 3:17 PM, GuyIsDamGood said:

 

 

Does anyone know what the 4-ohm wattage is on the Rotel RB-1582 Mk 2?

 

 350W/Ch (4Ω)   ,  200W/Ch (All channels driven, 8Ω)

 

 

[82 Cornwalls]

1 hour ago, OO1 said:

 350W/Ch (4Ω)   ,  200W/Ch (All channels driven, 8Ω)

 

 

 

Source?

[OO1]

Rotel 

[82 Cornwalls]

16 minutes ago, OO1 said:

Rotel 

 

Did you e-mail or call them? Is it in print where you can provide a link?

Not in owners manual or anywhere else I can find.

[JefDC]

21 hours ago, MicroMara said:

I´m not your math teacher 😂 I´m just a silly german guy ..and I don´t know wether you´ll understand this 🤔

 

The general formula of electric power is   

 

The following formulas apply to ohmic resistors in a DC circuit:

 

 

What is the unit of electric power? The unit of electrical power is watts:  

 

What does electrical power say? The electrical power makes a statement about how much electrical energy per time an energy converter ("consumtion") converts into other forms of energy.

 

The greater the power, the more energy is converted or transformed in a shorter time.

 

Got it 🤣

 

 

No need to be condescending.

When the resistance halves the power should double (using the formulas you quoted: P= U.I etc etc)

Not all amplifiers are able to do this, those that can will advertise this clearly in the Specifications of their amplifier.

As an example:

 

Got it ?

[GuyIsDamGood]

It's somewhat hard to believe that an amplifier company (Rotel) doesn't release/show the 4-ohm specifications of their RB series amplifiers.

 

Thanks to everyone for showing interest in my audio-amplifier question.

[mboxler]

Correct me if I'm wrong, but phase can play into this as well.

 

My memory may be fuzzy, but if an amplifier is driving a load with a -45 degree phase shift, only 70% of the supplied power is transformed into work.  The remaining power is reabsorbed by the amp and dissipated as heat.

 

In other words, to supply 100 watts of power to a driver @ -45 degrees, the amp will need to supply 140 watts and absorb 40 of those "unused" watts.

[MicroMara]

1 hour ago, JefDC said:

 

No need to be condescending.

When the resistance halves the power should double (using the formulas you quoted: P= U.I etc etc)

Not all amplifiers are able to do this, those that can will advertise this clearly in the Specifications of their amplifier.

As an example:

 

Got it ?

correct !

[the real Duke Spinner]

23 hours ago, GuyIsDamGood said:

It's somewhat hard to believe that an amplifier company (Rotel) doesn't release/show the 4-ohm specifications of their RB series amplifiers.

 

Thanks to everyone for showing interest in my audio-amplifier question.

Prolly they are not recommending the Current Draw for the Output Devices at such a load

[OO1]

23 hours ago, GuyIsDamGood said:

It's somewhat hard to believe that an amplifier company (Rotel) doesn't release/show the 4-ohm specifications of their RB series amplifiers.

 

they do ........350W/Ch (4Ω)   ,  200W/Ch (All channels driven, 8Ω)

[GuyIsDamGood]

Have anyone Tested the Rotel RB-1582 Mk ii under a 4 - 2 -ohm load?

 

Thank you

[billybob]

11 minutes ago, GuyIsDamGood said:

Have anyone Tested the Rotel RB-1582 Mk ii under a 4 - 2 -ohm load?

 

Thank you

Dang good idea...