150W Amp using STK4182II in bridged mode

[Ferchito]

Hi everyone,

This is one of my favorites chip amp using STK4182II in bridged mode, it can bring high quality sound with low cost and excellent performance.

The power supply has dual voltage of 40V and 5A current capability, better use two 10000uF in filter stage for power supply.

Let´s built them and enjoy.

[Tomom]

Hi Ferchito, let me be one to reply to your post; seems guys here dont give much damn to STK chips, though they are reliable and very good sounding. I started with 4048XI, designed PCB for it, can acomodate two hybrids on it + bridging circuit. It sounds great. Gives 150W out with +,-60V, and sounds even better bridged, +,- 35V. What is your application for STKs..Cheers...Tom

[Ferchito]

Originally Posted by Tomom

Hi Ferchito, let me be one to reply to your post; seems guys here dont give much damn to STK chips, though they are reliable and very good sounding. I started with 4048XI, designed PCB for it, can acomodate two hybrids on it + bridging circuit. It sounds great. Gives 150W out with +,-60V, and sounds even better bridged, +,- 35V. What is your application for STKs..Cheers...Tom

Hi Tomom, I agree with you about STK chips performance, my application for this circuit is for my personal entertainment, I designed PCB for bridged circuit and use two STK's for stereo amplifier and It sounds very good.

Regards,

[Ferchito]

Thats just one of more amps built in with stk module by me and i think thats sound great

[Tomom]

I have one problem with my STK4048 XI, the input is too sensitive. Any idea how to fix that?

[Jay]

Originally Posted by Tomom

Hi Ferchito, let me be one to reply to your post; seems guys here dont give much damn to STK chips, though they are reliable and very good sounding.

Actually they are not reliable. They don't have internal protection against short circuit, cannot drive low impedance load. Cheap STK-based amps don't have external relay at the output so they will fail very easily.

They are indeed good sounding (less fatigue than mos amp chips, even the Gainclone).

[Tomom]

Sorry for repeating my question, anyone knows how properly to condition input into STK4048XI? It is very sensitive, and bringing CD player or tuner signal gives almost full blast right at the begining. Thanks...

[AndrewT]

the feedback components set the passband gain.
I see 56k and 560r+100uF on both the non-inverting and the inverting sides.
This is ~40dB of gain.
Increase the 560r to ~1k5, will reduce the gain by about 10dB and also bring up the low bass output slightly.
You could experiment in using upto 2k4 for that 560r or reduce the 56k down towards 20k.

Existing non-inverting gain = 1 + 56k/560r = 101
Existing inverting gain = 56k/560r = 100

proposed gain = 1 + 56k/1k5 = 38.3 (+31.7dB)
or
1 + 20k/1k5 = 14.3 (+23dB)

[Tomom]

Hello Andrew, thank you for advice, I will try this and let you know of result.

[pacificblue]

Originally Posted by Tomom

seems guys here dont give much damn to STK chips

Right, LM and TDA are prefered. Not because they are objectively better, but they have better marketing, especially thanks to third parties, who make money from them. They are easier available, and they are usually cheaper. Also the documentation takes less effort to find and understand.

The newer STK types are hard to get and expensive. The older types are still sold, although they have been out of production for a long time, at least from Sanyo. This makes people wary about what they get, and those types usually also have specs that cannot compare to the LM and TDA amps, whether audible or not. Most of them are only specified as 8 Ohm stable, too.