Sub $500 Hypex or PFFB Amp for Kef R3 Meta? (USA)

[iTenth]

Looking to get an amp to power R3 Metas. I plan on sitting 15 feet away from them. I've looked at getting a Wiim Amp Ultra and according to SPL calculators, they should be find but i'd be maxing the amplifier.

Many of the Hypex amps end up being >$575 with Cheapest Nord AMP and Audiophonics being around $550.

I’ve looked at:

Topping PA7

I’m mainly looking for a transparent amp that’s not load dependent. It seems with PFFB being introduced into the budget amplifier market, they are now rivaling many more expensive Hypex Ncore Amps.

Not interested in buying a Fosi or Aiyima.

The plan was to pair it to a minidsp HD then Wiim Ultra or Wiim Pro. If it’s not possible might just get the Wiim Amp Pro or Sonos Amp.

 

[kyuu]

What inputs did you use on which SPL calculator? I find it difficult to believe that the Wiim Amp Pro (there's no Ultra that I'm aware of) would have any difficulty driving the R3 Meta to meet your SPL needs unless there's something unusual in your requirements.

For example, to get an average of a bit over 80dB at your listening position, which is quite loud, you're looking at needing 2 watts:

At the Wiim Amp Pro's full 120W @ 4R, you can get a bit over 100dB for a dynamic range of about 18dB, which should be sufficient for just about anything:

 

[livinon2wheels]

What inputs did you use on which SPL calculator? I find it difficult to believe that the Wiim Amp Pro (there's no Ultra that I'm aware of) would have any difficulty driving the R3 Meta to meet your SPL needs unless there's something unusual in your requirements.

For example, to get an average of a bit over 80dB at your listening position, which is quite loud, you're looking at needing 2 watts:

View attachment 424516

At the Wiim Amp Pro's full 120W @ 4R, you can get a bit over 100dB for a dynamic range of about 18dB, which should be sufficient for just about anything:

View attachment 424515

this is how I approach designing a system...actual dynamic range based on chosen amp and sensitivity of speakers. Brilliant!

 

[boXem]

What inputs did you use on which SPL calculator? I find it difficult to believe that the Wiim Amp Pro (there's no Ultra that I'm aware of) would have any difficulty driving the R3 Meta to meet your SPL needs unless there's something unusual in your requirements.

For example, to get an average of a bit over 80dB at your listening position, which is quite loud, you're looking at needing 2 watts:

View attachment 424516

At the Wiim Amp Pro's full 120W @ 4R, you can get a bit over 100dB for a dynamic range of about 18dB, which should be sufficient for just about anything:

View attachment 424515

Not exactly.
1. You are mixing sensitivity at 1W 8R and power in 4R.
2. The R3 have a quite serious impedance dip, so the amplifiet ability to deliver current should not be neglected in the calculations.

 

[kyuu]

1. You are mixing sensitivity at 1W 8R and power in 4R.

What? I'm not sure what you're getting at here. Sensitivity is taken from an average over a certain frequency range in a speaker's frequency response (at a standard voltage/distance). I don't see how the speaker's impedance curve is relevant here.

2. The R3 have a quite serious impedance dip, so the amplifiet ability to deliver current should not be neglected in the calculations.

Yes, but the Amp Pro doesn't have any issue with low impedances or severe phase angles, at least until it goes into protection:

I wouldn't say the Wiim Amp is superior to Hypex modules at all. I would just say that's it's more than adequate for most people's needs.

 

[boXem]

What? I'm not sure what you're getting at here. Sensitivity is taken from an average over a certain frequency range in a speaker's frequency response (at a standard voltage/distance). I don't see how the speaker's impedance curve is relevant here.

Sensitivity is measured at 2.83V RMS, which happens to be 1W in 8R. The "dB gain from amplifier" is established by calculating the ratio between 2.83V and output voltage at max power. So the value you need to enter is power in 8R, not 4R. Result will then be 3 dB lower.

Yes, but the Amp Pro doesn't have any issue with low impedances or severe phase angles, at least until it goes into protection:

I wouldn't say the Wiim Amp is superior to Hypex modules at all. I would just say that's it's more than adequate for most people's needs.

Subject is not stability but ability. If the amp shuts down to protection, the good news is that nothing was broken, the bad one is that there is no sound.
There are two questions:
1. Is the minimum impedance supported by the amplifier lower than the speakers min impedance? Yes should be the mandatory answer, I do not know it for the Wiim.
2. Is the power of the amplifier at speaker min impedance limited by it's current?
The measurement from Amir shows a current limit of around sqrt(113/2) = 7.5 A RMS.
Corresponding power in 3.2R (R3 min impedance) is around 7.5^2 * 3.2 = 180 W. Voltage limited power at the same impedance is 58 * 8 / 3.2 = 145 W, so the Wiim will not be current limited with the R3.
In the case when it would have been current limited, the voltage corresponding to the current limit in 3.2R should have been calculated, then the corresponding power in 8R entered in the calculator you used.

 

[livinon2wheels]

Not to throw a spanner into the gearbox, I have read some reviews of the Wiim amp that suggest it sounds strained with low impedance loads. I have no personal experience with the Wiim amp to say for sure this is true. But I would probably choose a different amp if it were me for speakers that present a difficult load to an amp. I would want to err on the side of more is better. What you actually need to be satisfied is such a personal thing and it may have nothing at all to do with the numbers.

 

[kyuu]

Not to throw a spanner into the gearbox, I have read some reviews of the Wiim amp that suggest it sounds strained with low impedance loads.

What does that mean? How would an amp sound "strained"? What exactly is a low impedance load? 4 ohm? 3 ohm? 2 ohm? Lower?