Multi Configurable Testing PCB for Papa’s SIT-PMosfet, SIT-NMosfet MUFF and DEFiSIT Amplifier

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To use those previously made FE boards with +/- power supply, a DC-DC power module with Mean Well DEK15C-24 is designed. Its input can be 36-72VDC and output +/-24VDC. Same as main power supply, a HF filter is put in.

 

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assembly and test. Input 48VDC, one module output +23.91/-23.90VDC, another module +23.86/-23.85VDC.

 

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After +/-24VDC power supply is running, the FE, which was designed for LuFet, is in the amp.

The IC headphone amp provides x4 gain and the 125:125 edcor connected to auto-transformer has x2 gain.

The amp sounds much better with FE.

 

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These are THD measurements with the FE at 1W, 5W, 10W, 15W and 20W output power at 8ohm.
H2(+90) is dominant thru the output power range.
One thing is noticed when measuring. THD of the output of focusrite scarlett solo G3 increases at high output voltage. this could contributed a portion of the THD at Higher power of the amp.

 

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SIT never sounds better before!

After the dual power supply is available, the BA-3 built few years ago is brought to live again as the front end.

The best combination so far. It is an unexpected surprise!

You guys needs to try it before Mr. Pass's new FE for SIT is available.

 

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This is the first time I use SMPS from the frond to the end in an amp. And this is the first time I am subjectively feeling that SMPS could reach the sound signature of traditional linear power supply. Pass BA-3 is really shining here.

 

[Zen Mod]

better invest in some damn shunt reg, instead of playing with zingyzingyswingy

 

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will try. the only reg hasn't been tried yet.🙂

 

[rolandong]

regulate the supply of FE, at least

 

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I made a Salas DCSTB reg behind Mean Well +/-24VDC SMPS power supply and got +/-16.4VDC for FE.
At same time, a Salas DCG3 front end was built to drive the SIT amp. I will listen this configuration for a while.