Hi all. I've come into possession of a 2016 VFET amp. It has worked perfectly while on test in my system. Last night however, I went to power it up, nothing. No blue LEDs no suggestion of power to anything. Almost like a fuse had gone... but if course, no fuse.
Which leads me to suspect the soft start circuit, or the traffo (a Toroidy). Ive tested the switch, because it was easy. Its fine.
I did not build this amp, but I know the person who did - sadly passed away - and his workmanship is super good. I am no expert but I can soldier, and solder away.. but I'm really keen to get your opinions on where I should start.. the soft start circuit is buried and will require a bit of strip down to test..
What's your gut thoughts? Thanks!
Which leads me to suspect the soft start circuit, or the traffo (a Toroidy). Ive tested the switch, because it was easy. Its fine.
I did not build this amp, but I know the person who did - sadly passed away - and his workmanship is super good. I am no expert but I can soldier, and solder away.. but I'm really keen to get your opinions on where I should start.. the soft start circuit is buried and will require a bit of strip down to test..
What's your gut thoughts? Thanks!
IMO you've got the correct idea. Get the soft start out of the way and check it. If mains is getting to SS board... and nothing is 'exiting' the SS board...
Can you post pics?
How confident are you with taking measurements with a voltmeter?
And what do you mean by "no fuse"? I'm hoping/guessing that you mean that the fuse is not the culprit. Fuses on mains operated circuits are not optimal.
How confident are you with taking measurements with a voltmeter?
And what do you mean by "no fuse"? I'm hoping/guessing that you mean that the fuse is not the culprit. Fuses on mains operated circuits are not optimal.
OPTIONAL, oh dear, fuses are not optional!
Some Mod please edit my previous post, lol
Some Mod please edit my previous post, lol
No, I meant there is no fuse in the circuit. Presumably, the builder of the kitset felt that the soft-start circuit was a suitable stand-in for a fuse.
The kit was / is a genuine diyaudio.com unit - marked on the pcb's "DIY Sony VFET Amp R0 First Watt 2016.
Previously, when switching on, a relay in the soft start circuit (im guessing) would click after a few seconds, and then the amp would power up. Currently, there is no relay sound. I'll check that, and the accompanying thermistor to begin with.. its just a bit of mission as they are buried under the main pub.
Fun fun
Thanks for your comments.
The kit was / is a genuine diyaudio.com unit - marked on the pcb's "DIY Sony VFET Amp R0 First Watt 2016.
Previously, when switching on, a relay in the soft start circuit (im guessing) would click after a few seconds, and then the amp would power up. Currently, there is no relay sound. I'll check that, and the accompanying thermistor to begin with.. its just a bit of mission as they are buried under the main pub.
Fun fun
Thanks for your comments.
This shows a soft start circuit - im not sure it is exactly the same as what features in the kit amp I have, but it looks like a good contender.
what you posted in #9 is not amp you have shown in pictures
look here : https://www.firstwatt.com/wp-content/uploads/2023/12/art_diy_sony_vfet.pdf , and find related thread on forum
anyhow, you need to check complete circuitry at mains side ......... IEC, fuse (there must be one!!), switch, soft start, primary
look here : https://www.firstwatt.com/wp-content/uploads/2023/12/art_diy_sony_vfet.pdf , and find related thread on forum
anyhow, you need to check complete circuitry at mains side ......... IEC, fuse (there must be one!!), switch, soft start, primary
Agreed. If there is a fuse, its well hidden.
Thanks for pointing me in right direction re the soft start
Thanks for pointing me in right direction re the soft start
Are you sure you don't have a fuse on the back panel itself? Is it a Schurter IEC? Many of them have fuse holders.
Best,
Anand.
Best,
Anand.
So, are we to understand that the fuse was not found to be in optimal condition?