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Class D Audio Amplifiers

Do, the Power supply can be modified to allow slower start, to fully charge the large capacitors before run normally. I can do it at no cost, but I do not advise anyone to do it himself because of the dangers involved when working with live connected circuits and chances to damage the unit if something goes wrong. basically the easiest way is to increase the value of only one capacitor which determine the soft-start time and power available during soft start.
The most suitable class D amplifiers which accept +-38V are TDA8950 based amps. Connexelectronic 6-8 modules can be powered from a single power supply. Also, being powered from SMPS, the rectifier bridge can be removed and lower capacitance caps can be used as the total capacitance of multiple modules powered from the same source will be large enough for proper operation.

Jay, the modules are available here http://connexelectronic.com/product_info.php/products_id/151
 
Do, the Power supply can be modified to allow slower start, to fully charge the large capacitors before run normally. I can do it at no cost, but I do not advise anyone to do it himself because of the dangers involved when working with live connected circuits and chances to damage the unit if something goes wrong. basically the easiest way is to increase the value of only one capacitor which determine the soft-start time and power available during soft start.
The most suitable class D amplifiers which accept +-38V are TDA8950 based amps. Connexelectronic 6-8 modules can be powered from a single power supply. Also, being powered from SMPS, the rectifier bridge can be removed and lower capacitance caps can be used as the total capacitance of multiple modules powered from the same source will be large enough for proper operation.

Jay, the modules are available here Connexelectronic

Hi Cristi,

If you don't mind sending the info to me it would be great. I've worked with tube amps with much greater voltage but I'm always extremely cautious. I'm ok to void the warranty of the product. I'm also extremely happy that you're offering to do it for free but the shipping charges to send and receive will end-up being way too expensive to be worth the trip.

So if you're ok to PM me the info then I would take 100% responsibility.

Thanks
Do
 
Cristi,

I wish to power my 2.1 home theater set up.
Stereo speakers are 6-10 ohms / 92db
Subwoofer is dual voice coil so it can run off a stereo amp or coils tied together for use with a separate mono amp. 4R / 85db
Stereo/sub crossover is around 150hz. Sub goes down to 30hz.

I've narrowed down my options based on power and costs.

Which amp power supply version would work best, heat, lowest distortion, etc?
Or is there a better choice I have overlooked?

SMPS300RE +-60V with CxD300-8R (2x200w) (2 modules that powers both speakers and 4R DVC subwoofer)

SMPS300RE +-45v with IRS2092 Stereo Amplifier (2x200w) (one module that powers both speakers and 4R, DVC (dual voice coil) tied together, subwoofer)

SMPS300RE +-36v with TDA8950 Amp V3 (2x120w) (2 modules, one stereo, one BTL for 4R, DVC tied together, subwoofer)

Currently I use one SMPS800RS on a ClassDamp SDS 258 and it sounds great.

Thanks
 
I don't see a clear mention about power rating of the SW, also, 6-10R impedance is a quite wide range. probably is 8R, and 6R is the DC resistance. I assume that a 2x200W amp would do the job. if so, here are my proposals:

1. one IRS2092 Stereo Amplifier powered from a SMPS500(Q)R at +-45V. using the amp with dual voicecoil speaker offers a great oportunity to use one channel 180* out of phase, which cancels the bus-pumping. of course that speaker terminals will be inverted as well.
2. one TDA8954SMPS powered amplifier Connexelectronic which can drive the voicecoils in the same manner as first proposals. both modules have balanced input, and using them in BTL mode is straightforward, connect the inverting input of channel 2 to non-inverting input of channel 1, and non-inverting input of channel 2 to inverting-input of channel 1 and supply signal accordingly. there's a diagram with example connection in the IRS2092 stereo amplifier manual.
3. lowest possible cost, IRS2092k amplifier kit. it comes unassembled, either bare board without components or full components set, so you have to solder them yourself and make them work Connexelectronic and supplied with a SMPS200QR (SMPS240QR and SMPS300QR will follow) Connexelectronic

Do, pls contact me by mail to send you informations about modification.
 
Just a remark to my above question:

This is from TDS8950th datasheet
"The noise generated by the internal oscillator is supply voltage dependent. An external
low-noise oscillator is recommended for low-noise applications running at high supply
voltages."


Could this be my problem? I don't know how internal oscillator noise sounds. I don't have a transformer with lower voltage to try this out.
For anyone who might still use these modules. The startup noise is dependant on voltage. I got at lower voltage transformer and the startup noise is gone.