The fun never ends. I have one channel that stays sub 50mv (DC offset) from cold to hot. The other channel starts at 125mv (DC offset) and .900MV (t18 to ground) cold only to go to 5mv(DC offset) and 50mv (t18 to ground) hot. I suspect I'm going to back track and revisit P1 and P2 and R32 before trying again.
Regards,
Dan
Regards,
Dan
I've revisited adjusting P1 and P2 again and their accompanying voltages across R5 and R6 and so far a huge improvement. Of course temperature and time could change this. Takes at least an hour or more to really heat up.
And then I have to let it cool down and retest. The main challenge previously was it's cold start up values.
More soon..............
Regards,
Dan
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My amp does the same thing. Coincidently it is also the right channel that starts cold with high speaker DC offset and high T18 voltage. But they drop down to acceptable levels once it's warmed up.
As I also mentioned in a previous post, these values vary from day to day, even hour to hour, so I stopped obsessing and just listen to the music.
FYI, my experience:
Post #252 Sony Vfet Illustrated build guide
As I also mentioned in a previous post, these values vary from day to day, even hour to hour, so I stopped obsessing and just listen to the music.
FYI, my experience:
Post #252 Sony Vfet Illustrated build guide
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that are good news, great. i also have to start over more then once. the good part is that you get a good feeling how the pots interact with the time. glad it worked out fine
Yes. Many thanks for the patience and support of my fellow DIYers. I'm just working on a well ventilated lid and then I'll post pics.
Regards,
Dan
1k pots vs 500R for P3 & 4
Hi,
I'm back to trying to get the store SONY VFET up.
Over the winter I tried seting up the pots and found
the single turn pots a royal pain to set. So ordered
some 500r multi-turn pots back in March.
Today I opened the polybag with the pots and
found that they packed 1k pots into the bag
marked 500r!!!
I've used 2sj313 & 2sk2013 Tosh mfets from NicMac.
I saw where 1k pots are advised if using Fairchilds.
Will the Toshibas be ok with the 1k pots? I'm
guessing it'll be ok.
Just wondering how that impacts Q1,2,3,4 ?
Hi,
I'm back to trying to get the store SONY VFET up.
Over the winter I tried seting up the pots and found
the single turn pots a royal pain to set. So ordered
some 500r multi-turn pots back in March.
Today I opened the polybag with the pots and
found that they packed 1k pots into the bag
marked 500r!!!
I've used 2sj313 & 2sk2013 Tosh mfets from NicMac.
I saw where 1k pots are advised if using Fairchilds.
Will the Toshibas be ok with the 1k pots? I'm
guessing it'll be ok.
Just wondering how that impacts Q1,2,3,4 ?
Thanks, will order 500R, when ? who knows. Have to make
up enough parts to justify an order. Oh well, this project started
over two years ago! What's a little longer.
you can cheat - solder 1K resistor between two outer pins of trimpot
Voila! ...... 500R trimpot (with some funny law , but close enough for purpose)
Well, ok then.
Thanks, will order 500R, when ? who knows. Have to make
up enough parts to justify an order. Oh well, this project started
over two years ago! What's a little longer.
I just went through this to a very satisfying end. Yes setting the pots are a major pain in the *** but well worth the effort!
Regards,
Dan
