Interesting!
I plan to buy a Fosi pre-amp and headphone amp ...
It is class A ...
Fosi sk01...
I will use it with my active speakers and my secondary headphone ...
Fosi Audio V3
It’s a marvelous very cheap class D amplifier based on the TPA3255 chip, with a great finish, good components (genuine Nichicon, NCC, and Wima caps, Japanese Sumico inductors, NE5532 op-amps in sockets - Fosi Audio recommends you to swap for the better op-amp of your taste) in a lovely, understated and "serious" casing that receives a special attention to cooling.
I purchased two, because I’m actively tri-amping (the subs having their own amps); I’m driving super efficient horns (even the bass section is 104dB sensitive) so the little Fosi with its 48V PSU should just be cruising along.
Currently I’m using a TPA3116 on the bass, and a Tripath TA2024 on the mids/highs. And it sounds amazing. Part of the reason it sounds amazing is that the TA2024 amp is fed by a very nice low noise linear PSU with ample power.
I’m not sure the Fosi V3 will be able to sound as good, let alone better, especially on the high pass; it will probably sound great on the bass. But having two identical amps for the high pass and low pass is in theory ideal; headroom should be even more, and also my TA2024 amp is sensitive to external perturbations and, in my current house, it picks up some radio signals and sometimes modulates weird noises in the system.
Now I wonder if I should later on feed the high-pass V3 with a linear PSU (I can find some nice 24V) or just keep on using the SMPS bric. Or maybe a better SMPS like a Mean Well?...
I’ve also ordered four Oracle 02 "discrete" op-amps (in fact they are, I believe, hybrids) to replace the 5532.
I’ve said it before: I like my system to be left ON 24/7, and tiny class D amps are PERFECT for that, of course. I’m aware class A would sound much better, but it’s not something I want to deal with at this point of my life.
Class AB on the other hand is a mixed bag: to me it doesn’t necessarily sound better than a good class D, so the higher size / cost / consumption isn’t necessarily worth it. YMMV, of course.
I should receive the two amps soon, I will post my impressions.
Source is a Gustard X26Pro DAC; preamp is a DIY Pass B1, and active crossover is a Sublime Acoustic K231.
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@mahgister I have a friend who is using a 125$ tube preamp from Douk Audio in his main system. He swapped a few caps, put better tubes in, and is super happy! I think the model is "Douk Audio P1" :-) |
Thanks ... It seems promising but i ordered the Fosi already ....
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I am happy with the Fosi SK01 ... Perfect job to amp my secondary headphone (AKG K701 ) used for movies... There is better for sure but at the price paid with three tones controls which help a lot to make the unnatural K701 to my taste i decided that China as Schitt does can make great product at low cost ... I decided to ordered a tube pre-amplifier, the douk P2 pre-amp with also three tone controls i will need for my excellent active small speakers ... Well embedded mechanicvally, and electrically as acoustically i like them now after a hateful relationship for 10 years in spite of his very good reviews... I modified the tweeter waveguide and redesigned the porthole... Stunning improvement... I can now listen music and i decided a tube pre-amp. with three tone control will help ... The Douk P2 was paid 50 bucks ... i think that China able to put robot on the moon now and testing right now a 1000 km/hour train is able to make a minimalistic good pre-amp at low price ...😊
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I am now happy with the tube preamplifier P2 of Douk... I use it for my active speakers... Astounding , better holography and the tone controls are useful to maximise the speakers sound ... Peanuts cost... No downside for me ... I use the Fosi sk1 for my AKG K701 for movie essentially ... Same thing no downside ... The low cost chinese product are not all junk ... Many compare well and for a better price sometime than Schiit products for example or other european products ... https://www.youtube.com/watch?v=bKdv7C5KcPY&t=10s They are not high end if we define high end product by price tags ... But nevermind the price , any gear system need to be optimized mechanically, electrically and acoustically to reach his implicit acoustic potential contribution.. Then i quit these triple misleading distinction between high end, mid-fi, and low-fi or chi-fi , which are very deceptive on many counts ... The only valuable and objective description is by comparing acoustic factors , each one of them as balanced or not once compared to the others factors contribution in the creation of the soundfield impression , being transients, dynamics, timbre , bass , imaging, holography , immersiveness etc.. Then the only valuable distinction is between after and before the necessary triple optimization process is this question : with this low cost system, with what i own have i reach the minimal acoustic threshold of satisfaction or not ? Or with this highly costlier system , have i reach the maximum acoustical satisfaction threshold ... In the two case the minimal as the maximal acoustical satisfaction threshold , we are happy and not at all in a stop-gap phase... But if our system is not well embedded nor well optimized acoustically , mechanically and electrically , nevermind his price , the unbalance between acoustics factors and parameters will induce frustration and unhappinness ... Then classifying systems between low-fi, mid fi and high fi , not only is deceptive but hide the real and necessary optimization process by the illusion of the costlier the better ... It is false ... All that to say i am in ectasy with my low cost tube pre-amp ... In a minimal acoustical satisfaction threshold for sure , but the minimum well done is enough believe me ... |
I have one here and I will be starting to mod it this week. I am going to remove the first set of electrolytic coupling caps and the opamp and replace the second set of electrolytic coupling caps with modified Wima caps. I will then drive the chip balanced directly from the balanced outs on my DAC. I will use the DACs internal digital volume control and set the voltage amount out (via the IV stage in the DAC) so that I use very little digital attenuation. I also plan to change the output filter caps to modded Wima Polyporps (the stock caps are steel leaded polyesters). Of course, better output connectors and power supply coming too. |