Wow, how this "burn in" process seems to polarise people and their opinions. Having designed, prototyped, repaired, restored and recapped countless pieces of audio gear over the decades I can honestly say that I've never experienced this "burn in" phenomenon on electronic components or cables. Mechanical parts - yes if you call this "burn in" as suspensions in speaker drivers, cartridge cantilevers, bearings settle in, but on well made parts this is generally a pretty quick process. I'm not sure who started this whole "burn in" process on electronic parts, cables, fuses et al but unless I'm totally audio engineering inept (perhaps deaf ) it's imagination or perhaps a process of acclimation to the sound. I tend to lean towards the latter. Now I fully expect these comments will invoke the ire of some. That's to be expected. It's the audiophile community after all and if you are after controversy just get a group of audiophiles in a room and introduce the "burn in" topic. You'll quickly observe the groups separate into their respective camps each extolling their points of view for and against. Some will always bring up the electrolytic capacitor issue. Yes, new electrolytic capacitors that have been stored unused for many years should be re-formed to ensure the dielectric strength and other key parameters are still good. I do this by testing them at their nominal working voltage BEFORE installing them. Any issues thereafter with capacitance, ESR, leakage and dielectric losses can be checked prior to putting them is service. However newly manufactured electrolytic capacitors should be perfectly okay to instal and use without any prior testing. In this case the dielectric re-forms in a matter of less than a minute and no further changes take place. Some of the things I believe influence audiophiles when it comes to these controversial "beliefs" are - Advertising hype. (Yes. I fully admit to making some decisions based on the success of this. ) Peer acceptance. My audiophile friends believe it's true and I don't want to be the outsider in the group or seen to be not hearing the difference "burn in" makes. The eternal search for "audio Nirvana" which never seems to be satisfied. Pre-conception and pre-expectation bias. Confirmation bias. (After all you spent the big bucks or sacrificed a lot of hours waiting and now you expect an improvement, right?) Self justification for a decision even if whatever you expected didn't come to fruition. (and possibly the most contentious) - a feeling of superiority - my system and hearing is vastly superior to yours. I often hear the line ".... you can't hear the difference because your system isn't resolving or high-end enough.... " Have I made a few more enemies?
I have never noticed the phenomenon of burn-in with cables, but I have friends who swear by everything that it exists, but with speakers and devices I have noticed it, as if more with amplifiers than with sources. Maybe there are explanations related to the electronics, maybe the audiophiles are set that there are differences and then they hear them, maybe the fact that you get used to the new sound. Or maybe vice versa, you are a specialist, you have no technical explanation for the phenomenon, you are set that burn-in for devices does not exist and then you will not notice any difference. Some say it's a conspiracy by the manufacturers, because if the customer thinks the sound will improve after a few hundred hours, he won't return the product that doesn't satisfy him within the time frame he has the right to do so.
You make comment about @Mister L making mention of a Fosi amplifier and comparing it to the F2 on the eversolo F2 forum making it sound like it's an inappropriate place to compare the two, however in the same post you make mention that you will in two days go to the Adriatic coast. What has your travel to the Adriatic coast got to do with an F2 amplifier? If you are going to be a pedant and insist on others not posting comparative comments about other amplifier in the F2 forum pages at least practice what you preach.
Today I had the opportunity to listen to a pair of Fosi V3 Mono on my system and I did not like it, sibilants and highs with a metallic sound, maybe with other op-amps it sounds better, but otherwise it is much below F2. I don't understand what is all the fuss about them, you pay 300 euros, 100 euros is worth it. I'm waiting for my friend to change the op-amps, let's see what and if he can do more.
Many budget Class D power amps of which the Fosi V3 Mono clearly fits in to that category don't always produce a flat frequency response in the upper frequency region. This is due primarily to the simplified low pass filters used in the output to strip away the switching frequency which is typically well above the audio range at 500kHz or higher. The reactance of the inductive and capacitive components in these filters usually exhibit a falling or rising output in the upper end of the audio range depending on the load impedance connected to it. So a typical Class D amp optimised for say a 5 ohm resistive load may exhibit a flat frequency response over the audio range of 20Hz to 20kHz, but typically exhibit a slight roll off with a 4 ohm load and a rising output at 8 ohms. (see the attached frequency response graph of the Fosi V3 Mono). Now, speakers rarely exhibit a flat impedance to an amplifier at all audio frequencies. So even if the nominal speaker impedance is say 4 ohms, this won't be the same across the entire audio frequency range. A speaker that has anything but a flat impedance characteristic may sound quite good on a Class A or Class A/B amplifier but may sound less than impressive on a Class D amplifier of similar output power. Now before anybody gets their nickers in a twist I will hasten to add that this generalised observation is typical of the cheaper Class D amplifiers and doesn't necessarily mean all Class D amplifiers operate or sound like this. However, I would highly recommend you listen to any Class D amplifier you intend to buy with the speakers you are going to be using it with before committing to the purchase. BTW, IMHO changing the op-amps in the Fosi V3 may not reap the changes to the sound quality as an improvement you might be hoping to achieve for the reasons I've outlined above.
Thanks for the answer, I don't intend to buy them, I just tested them and that was my impression, their owner is not happy either, but he hopes they will burn in and will sound better. I also tested the F2 6 months ago and I really liked it, it was quite close to my Classe Sigma 2 amplifier ( also classD power amplifier) and it even sounded better at low volume, as I often have to listen to. In the meantime I bought an Advance Paris A 12 Classic with which I am extremely happy.
I am considering buying one of those Eversolo Amp-F2, can someone tell me if they get hot when they are in use? I need an amp which is running cool when in use, because I have to place it in tight space. best regards Kim
I have a F2 amplifier, don't worry it is a D Class amp that is generally not heated like A or AB amplifiers.
If you play with modest to loud levels how hot dos the amp gets if you touch it? also when it turns on, is there any click or pop in the loudspeakers? BR kim
Do you experience any click or pop in the loudspeakers when you power on? do you use trigger? I have read others experience this.
I use two trigger cable and of course, click is heard when you turn on or off. This is in amp, in speakers nothing heard.
I have Triangle ZAYS XS floorstanding speakers and an eversolo A6, I'm looking for an amp and try to find out a lot on the net but haven't had the opportunity to do a single real test yet. After my research I chose Fosi ZA3 as Mono Block, Musical Fidelity, Marantz, and I'm waiting for the tests of the new Cambridge EXA 100. But when I read that owners of high-end products like Musical Fidelity Nuvista or Cambridge Audio Edge have switched to Eversolo F2, I admit to being lost, interested and perplexed at the same time.
Andrew said that F2 goes up in the treble when you increase the volume, which would be a problem for me with my Triangles which are already shiny on the tweeter. On the other hand, its comparison with high-end products shows very minimal differences
I also have Triangles. The Cometè EZ. And I can also say, that they are already shiny on their tweeters. I tried and already have two Fosi ZA3 with Muse 02 OP Amps. As PRE I use RME Adi-2 DAC FS. I can say that the hights at higher volume are a little bit harsh. Last week I got a Hegel H90 from a friend for testing. I think this Hegel is a very good match to the Triangles. Sounds more natural in the hights and has also better mids. Think this Hegel H 90 will become my next Amp. I tried these Class D Amps form various manufacturers and in various price ranges. For me I go back to more old school. Sounds better to my ears.
I listened in two systems Eversolo F2 and Fosi V3 (my system and a friend's system, we tested both amplifiers at me and at him). I think the F2 is a very good amplifier in its price range, I didn't like the V3, it sounds metallic and with a lot of sibilants, only the bass is good. Do yourself a favor and forget about him.
