Amp works 
Well, since I was not successful even I knew, the V-Fet was right, I wanted to finish another project first to gain confidence. And I did - Salas DCG3 preamp.
Today I was looking for a cold joint in the Fet part and I found it at the HEXFet. Was hard to see, but good to measure.
And now, the amp is warming up. I am really happy about that. Need some more patience for the adjustment.
Have a nice Sunday
Well, since I was not successful even I knew, the V-Fet was right, I wanted to finish another project first to gain confidence. And I did
- Salas DCG3 preamp. Today I was looking for a cold joint in the Fet part and I found it at the HEXFet. Was hard to see, but good to measure.
And now, the amp is warming up. I am really happy about that. Need some more patience for the adjustment.
Have a nice Sunday
get youself at least 3 Multimeters! one for Vfet (R32) bias, one for Frontend offset and one for speakers offset. I found the Voltagedrop of about 1,5V over ..was it R6?...the most UN-critical value, not having the habit of running away.
Frontend offset still wandering between +-70mV in mine. Nevertheless sounds very good. Maybe termal coupling of the jfets would help.
good luck!
Hi Noelectrix, thanks! I do have 3 DMMs and have adjusted my first channel 2 weeks ago or so. I just have to adjust the second one which I was not getting to work before. After having finished the Salas pre today is a good day and next week a good week to give it a first listening session.
You can build open " input & output " box with quality switch inside and
the same color pairs of wires with crocodile clamps for easy visualisation of your tests points.
With 8 position switch you have equivalent of 8 multimeters with only one.
Yeah take care make slowly little value changes steps
the same color pairs of wires with crocodile clamps for easy visualisation of your tests points.
With 8 position switch you have equivalent of 8 multimeters with only one.
Yeah take care make slowly little value changes steps
Attachments
When I had the amp up and running (and at temperature) I redid the frontend and output stage bias on the live amp, using four DMM's. It was fun watching the pots interact and slowly and iteratively approaching the minimum offset operating point.
The audio quality of this Sony VFET diy amp still amazes me every single day.
The audio quality of this Sony VFET diy amp still amazes me every single day.
Attachments
Rodeodave,
When you implemented the TL431 shunt regulators for the front end cascode circuitry from VFET pt2 article onto the diy audio VFET board, did you purposely omit the R24 (332 ohm) resistor? Did you implement R29 and R30 the cascode feedback resistors (each 10k)?
Thank you, your build is awesome
Best,
Anand.
When you implemented the TL431 shunt regulators for the front end cascode circuitry from VFET pt2 article onto the diy audio VFET board, did you purposely omit the R24 (332 ohm) resistor? Did you implement R29 and R30 the cascode feedback resistors (each 10k)?
Thank you, your build is awesome
Best,
Anand.
Last edited:
