NEW Audio amplifier kits, modules and many others.

[Cristi]

Jack,
the aux. voltage is supplied from the main transformer, so will have this voltage only when the smps will be on. to control the smps with remote option, must provide a 5-12V at 5-10mA to the remote connector from an external supply. if you want to use this option, must remove the small jumper between the optoisolators and one big capacitor. with this jumper on, the remote function is disabled, making the smps to be on all the time when power is applied. do not connect the aux. supply to the remote, use an external available supply.
the voltage can be adjusted within 3-15V from the potentiometer which is on the edge of the board. the maximum voltage which can get is about 18-20V when the main output has a load of at least 1 A current draw and if you change one resistor connected to the voltage regulator. available current is up to 500mA.

[Jack musician]

thanks very much cristi

[glt]

I read the description of the PS and it says "without PFC". Apologize for my lack of knowledge on this subject, but what is the significance (for audio) that the PS does not have PFC? What other advantages disadvantages are afforded by the PFC?

Also, the larger optional heatsink seems 2x taller. Are there options to keep the low profile but more heatsinking?

Thanks.

[Cristi]

PFC means Power Factor correction. in most of the countries it is required that the power factor of an electronic equipment which exceed a specific power to be >0.9
most of the smps, the ones without PFC draw nonsinusoidal input currents with a high harmonic content. This causes stress for the power wiring, circuit breakers, and electric utility. In addition, these harmonics can affect other electronic equipment connected to the same power line. Active power factor correction (PFC) that reshapes the input current before its application to the switch-mode supply solves this problem.
for example for Europe there is EN61000-3-2 Standard, which limits allowable ac line current harmonics. there are 4 classes, which characterize the type of the type of the equipment and ratings.
some more infos about PFC can be read on wiki Power factor - Wikipedia, the free encyclopedia
but in the audio field, most of the power amplifiers, even in proaudio lack of PFC.
for most of the commercial energy consumers there is no difference in the price for real power and apparent power, but for industry and big consumers there are a lot of regulations and penalities if they exceed the maximum values for PF.
one important thing to remember is that a power factor stage in a smps altough will improve the shape of the current drawn mains, will decrease the global efficiency of the smps. typical efficiencies only for the PFC are between 90% (old models or small power) to a maximum of >98% for power >300W or with some "exotic" topologies (bridgeless PFC, intereaved, active clamped, etc.) in the KW range and industrial stuff, up to 99% efficiency can be achieved.

the extraheatsink has 45-50 mm height, not more than the overall heiht of the capacitors and transformer. in the photo from the website is one big heatsink which i used just for test. i will update with the actual heatsink picture this days.

[hawui1]

cnx you've a pm

[dubai2000]

Another input resistor question - this time regarding the TA2022 amp. The value of R15/17 is.......I am guessing....47k? Clarification will be appreciated -thx.

[wingman]

wish digital amp gives most power on 12v dc from an batteri in 4 ohm?
Can't find spec for that.

[Cristi]

Originally Posted by dubai2000

Another input resistor question - this time regarding the TA2022 amp. The value of R15/17 is.......I am guessing....47k? Clarification will be appreciated -thx.

R15 and R17 are connected in parallel with the input and together with R8 and R9 set the amplifier input impedance. moreover, they are useful for proper biasing of the input capacitor, so if the amplifier is left without input signal connection, will reduce the background noise and the click/pop when the source cable is connected.

Originally Posted by wingman

wish digital amp gives most power on 12v dc from an batteri in 4 ohm?
Can't find spec for that.

i'm working at a design of an amplifier powered from 12V. there will be few versions, with power in range of 2x70W to 2x350W.

[wingman]

Originally Posted by cnx

i'm working at a design of an amplifier powered from 12V. there will be few versions, with power in range of 2x70W to 2x350W.

Very nice

Do you have an eta.?

[Cristi]

hopefully by the end of this year will be available. lately i was quite busy with some delegations.