Fosi v3 load dependency with Elac dbr62 - A problem?

[Wasteecity]

I recently bought a Fosi audio V3 amp and I'm looking to buy some speakers. Fortunately I've found some Elac dbr62's used for $220. But should I buy them? As you can see at around 20khz they have an impedance of 10ohm:

And that brings up an problem. The Fosi V3 amp has load dependency as you can see here:

Should they behave fine what do you guys think and how does load dependency actually behave? is it linear? like gaining 0.2db per ohm at 20khz for example or how can you calculate it? I mean personally I like having a little gain ,(~2-5db) at 20khz for a bit of air especially looking at the Equal loudness contour. So maybe it actually might be perfect? What do you guys think? Should I buy them yes no maybe?
But it worries me since I've read some people having trouble with the aiyima a07 which is based on the same chip having a gain of 15db sooo.

Besides getting elac dbr62's I was thinking about getting Infinity alpha 50's which I also found used which doesnt have the same impedance problem though a bit bassy here the frequency response:

The green/turqoise is the response on axis

let me know what you would do

Credits:
Measurements done by Amirm (besides last one)
https://www.audiosciencereview.com/forum/index.php?threads/fosi-audio-v3-amplifier-review.45757/

Elac Debut Reference DBR-62 Speaker Review

This is a review and detailed measurements of the Elac Debut Reference DBR-62 bookshelf speaker. It was kindly purchased new and drop shipped to me for testing. The DBR-62 costs US $600 a pair from multiple sources/dealers. The DBR-62 comes in black and walnut finish or the distressed Oak and...

www.audiosciencereview.com

 

[staticV3]

Should they behave fine what do you guys think and how does load dependency actually behave? is it linear? like gaining 0.2db per ohm at 20khz for example or how can you calculate it?

It's a simple voltage divider between output impedance and load impedance. If you know both impedances as well as the Amp's unloaded frequency response, then you can calculate the response with a load impedance of your choice.

It may be possible to estimate the Fosi's unloaded frequency response and impedance response from Amir's 4Ω/8Ω graphs, though not super easily I think.

But should I buy them? As you can see at around 20khz they have an impedance of 10ohm:

I think it'll be fine.
With 8Ω, you have +1dB at 20kHz, 10Ω might push that up to +1.5dB or so. Still barely worth mentioning.

 

[Guddu]

Elac DBR62 are amazingly good for the price, 220$ for a pair is a steal. Where do you see that price?

 

[Wasteecity]

Elac DBR62 are amazingly good for the price, 220$ for a pair is a steal. Where do you see that price?

Its used on ebay so not really new but I live europe and Recently I saw them new for 300 on mediamarkt fyi

 

[Wasteecity]

It's a simple voltage divider between output impedance and load impedance. If you know both impedances as well as the Amp's unloaded frequency response, then you can calculate the response with a load impedance of your choice.

It may be possible to estimate the Fosi's unloaded frequency response and impedance response from Amir's 4Ω/8Ω graphs, though not super easily I think.


I think it'll be fine.
With 8Ω, you have +1dB at 20kHz, 10Ω might push that up to +1.5dB or so. Still barely worth mentioning.

Thank you for your response

 

[NoMoFoNo]

The Elacs are 86db sensitive so if you didn't buy the 48V/5A power brick it may be worth considering. I've been using the V3 with a pair of JBL Studio 590s and the sound is excellent. I predict you'll love the set up.

 

[Wasteecity]

The Elacs are 86db sensitive so if you didn't buy the 48V/5A power brick it may be worth considering. I've been using the V3 with a pair of JBL Studio 590s and the sound is excellent. I predict you'll love the set up.

I actually did buy the 48v power supply version, and I will get the elacs today

 

[Rosenbloom]

I actually did buy the 48v power supply version, and I will get the elacs today

Hi, Do you mind to share your thought on your new setup? I am interested in getting the fosi and elac as well. Cheers

 

[Wasteecity]

Hi, Do you mind to share your thought on your new setup? I am interested in getting the fosi and elac as well. Cheers

Hi! I think the load dependency isnt really a problem. Speaker wise they're good but definetely need a subwoofer (but thats obvious). They sound very clear and the directivity is really good. Though a Note on the Fosi, it makes me sad that aux output isnt affected by the volume I have to change the volume on my source, and find the sweetspot with the speaker volume. I'm pleasently surprised by the noise because you hear nothing! I'm holding my ear next to the woofer and its just silent which is nice. But overall they're wonderful, especially with well mastered music! I didnt really notice the difference on headphones but oh does it make a difference on speakers because I have bad speaker placement and you dont on headphones. Overall they're very nice. Also the fosi gives enough power for the speakers. If you have more questions just ask me.

 

[Rosenbloom]

Hi! I think the load dependency isnt really a problem. Speaker wise they're good but definetely need a subwoofer (but thats obvious). They sound very clear and the directivity is really good. Though a Note on the Fosi, it makes me sad that aux output isnt affected by the volume I have to change the volume on my source, and find the sweetspot with the speaker volume. I'm pleasently surprised by the noise because you hear nothing! I'm holding my ear next to the woofer and its just silent which is nice. But overall they're wonderful, especially with well mastered music! I didnt really notice the difference on headphones but oh does it make a difference on speakers because I have bad speaker placement and you dont on headphones. Overall they're very nice. Also the fosi gives enough power for the speakers. If you have more questions just ask me.

Hi, Thank you! Glad to know that there is no hiss / noise issue!

 

[burkm]

Hi! I think the load dependency isnt really a problem. Speaker wise they're good but definetely need a subwoofer (but thats obvious). They sound very clear and the directivity is really good. Though a Note on the Fosi, it makes me sad that aux output isnt affected by the volume I have to change the volume on my source, and find the sweetspot with the speaker volume. I'm pleasently surprised by the noise because you hear nothing! I'm holding my ear next to the woofer and its just silent which is nice. But overall they're wonderful, especially with well mastered music! I didnt really notice the difference on headphones but oh does it make a difference on speakers because I have bad speaker placement and you dont on headphones. Overall they're very nice. Also the fosi gives enough power for the speakers. If you have more questions just ask me.

The upper frequency limits of an adult person are falling rapidly due to the age of the adult. A person in the mid 40th might barely hear 13 kHz, an even older person will have an even lower frequeny limit of his hearing. So he might actually not hear anything relevant, which falls within that portion of the frequency curve, were it might rise due to an uncompensated output filter of the class D amp. The corresponding rise might even help a little, because the frequency amplitude of his hearing will fall like a filter curve at the highest frequencies...

 

[CURRUPIPI]

Hello, I have also a Elac DBR62 and Fossi V3 with 48V supply since two days ago, and thanks to all the folks of this forum. For my surprise, the total volume at full knob is not really loud, and it has been tested with a Arylic BP50 and a Topping E30II DAC with similar results. In fact , it is only a tiny fraction of the output power of my Yamaha Pianocraft amplifier and speakers (60w/channel). I have to set the DAC at 100% power and Fossi V3 at 75% or so for a loud listening. Is it ok or maybe i have a faulty Fossi V3? On the other side, the sound is amazing, clear, pristine, full of detail, a really please to listen.
Would like to know your opinion, and how could i measure the current speaker output volume and compare with the one of other person with similar configuration (maybe with a smartphone?). Thanks

 

[burkm]

The gain factor of the V3 might be less than what the preamps and the DAC might add. The (gain) volume potentiometer of the V3 is of the A type, meaning, that it has logarithmic characteristics, which follows the loudness increase of our own (human) hearing. The combination of a preamp with the V3 power amp should be more than enough to reach the usual limits of the human hearing (and full power too). I myself got the Arylic BP50 preamp plus the Fosi Audio V3 (48V power supply brick) too and the Wharfedale Linton Aniversary speaker edition and reach a more than needed output at the medium settings of both. If I would set the Fosi V3 to its max position, the BP50 would probably be (almost) in its lowest position. The preamp should generate the usual 2V rms for driving the V3 (which is exactly what the BP50 does) to its max. (undistorted) output.
It (naturally) depends then on the dynamics of source material, if you reach the needed output power (your liking) of your speakers...

 

[CURRUPIPI]

Thanks for your response, in that case I'll take a close look at the specs of both speakers (Elac bdr 62 and yours), maybe the difference in sensitivity could make the difference. I also drive the Arylic BP 50 at full volume, but the Fosi V3 needs to stay near the full max. I have also a current meter, so I will watch the power driven into the amplifier.

 

[Wasteecity]

The upper frequency limits of an adult person are falling rapidly due to the age of the adult. A person in the mid 40th might barely hear 13 kHz, an even older person will have an even lower frequeny limit of his hearing. So he might actually not hear anything relevant, which falls within that portion of the frequency curve, were it might rise due to an uncompensated output filter of the class D amp. The corresponding rise might even help a little, because the frequency amplitude of his hearing will fall like a filter curve at the highest frequencies...

I'm 16 and hear up to 19khz,

 

[Doenerkunde]

I have a pair of Elac DBR62 and bought a Fosi V3 out of curiosity. Below is a inroom (untreated room, no EQ) comparison between my Class A/B Marantz and the Fosi V3.

Pretty much exactly what Amirs Review predicted: A steady rise between 2khz and 20khz of about 1dB or so.

Congrats on your new setup! I´d say you made a good choice.

 

[burkm]

I'm 16 and hear up to 19khz,

Steadily declining whilst getting older

 

[Wasteecity]

I have a pair of Elac DBR62 and bought a Fosi V3 out of curiosity. Below is a inroom (untreated room, no EQ) comparison between my Class A/B Marantz and the Fosi V3.

Pretty much exactly what Amirs Review predicted: A steady rise between 2khz and 20khz of about 1dB or so.

Congrats on your new setup! I´d say you made a good choice.

View attachment 325269

Thanks Also good that theres a measurement of it for people who might be scared of the load dependency

 

[Wasteecity]

Steadily declining whilst getting older

sadly yeah but theres nothing much you can do about it, you just gotta make the best of it and be careful with Volumes

 

[wyup]

Is the Fosi powerful enough with the DBR62? I doubt it. They require current down there.

Also, seeing you associating it with a preamp, no one thought of Fosi's own P3 tube preamp? I asked them and P3 has a 3.4db gain which could boost P3 performance.

The load depending thing could improve Elac's rolled-off highs from 10Khz on...