Grounding micpre

[Voyager10]

Yes. It remove some of the upper fq problems. (DI-shorted.png). If u look on my first layout pic there is still ground runing to the input transformer inside the veroboard, is that a problem?

No, not a problem for now. Thanks for doing the test.

The HJFP circuit has very poor power supply rejection, so power supply ripple will always cause a problem, even if the earthing was perfect.

Let's fix the power supply issues first, aim to get it silent when the HJFP1 input is shorted, and then see what is left when the inputs are reconnected.

 

[pazduha]

Ty all for suggestions. I have rewound the second secondary of the power transformer.
Now the measured values under load are:
25.5VAC to the diods
31.5VDC after diods
23.94VDC after regulator



This is without the box, only front and back panels, pins1 all connected by a tick wire. Pins 2&3 shorted.
Its a huge improvement in the low mid range. I guess the main problem was regulator not getting enough juice.

Next I have to get everything in a box. For ripple measurment I have to buy another film capacitor, both I own are in the circuit.

Cheers, ty

 

[ruffrecords]

Doesn't the AC range on multimeters already have a DC-blocking capacitor on the input?

As often as not it is just a bridge rectifier in front of the dc meter section. Easy to check by connecting to a known dc source.

Cheers

ian

 

[pazduha]

I think the noise is ok with everything in the box. I dont think I will make another PSU box, or try differnet JFETs. Maybe when I get some reference for good sound on some later project. Probably Classic solo next.

Thanks all that helped in this thread. And ofc especially to My3gger for all the help before that.

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