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Sony Vfet Illustrated build guide
Sony Vfet Illustrated build guide
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Old 10th February 2018, 12:34 PM   #481
stijn001 is offline stijn001  Netherlands
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Sony Vfet Illustrated build guide
Quote:
Originally Posted by mr_whocares View Post
many thanks, stijn. would you please share the dc-offset values at cold state and after 1.5h warming up?
do you hear a difference in sound quality when the offset changes duo to the airflow condition?

best regards


I measure:


L channel, cold: 152mV, warm -7mV
R channel, cold 225mV, warm 20mV


I don't know what I can attribute sound wise to the fluctuation in the offset. The amp does sound better warm.
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Old 10th February 2018, 02:28 PM   #482
delecoy is offline delecoy  United States
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Sony Vfet Illustrated build guide
May be a good idea to check that all the fasteners are tight. Mosftet/vfet bolts, heat sink bolts, etc.
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Old 11th February 2018, 10:03 PM   #483
Telstar is offline Telstar  Italy
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Quote:
Originally Posted by stijn001 View Post
However I find the amp becomes smoother & more natural sounding after it's had time to warm up.
That is normal of every amp
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Old 13th February 2018, 03:18 PM   #484
brandanbooth is offline brandanbooth  United States
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Default Need help one channel issue

I biased up the channel and everything looked good so i installed the vfets and my test voltage from t1 to -v is 6.8Mv the highest i can get it is 7.0mV the amp is not getting warm either. do you guys have any ideas that could help me T/s this?
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Old 13th February 2018, 04:29 PM   #485
Botte is online now Botte  United States
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Quote:
Originally Posted by brandanbooth View Post
I biased up the channel and everything looked good so i installed the vfets and my test voltage from t1 to -v is 6.8Mv the highest i can get it is 7.0mV the amp is not getting warm either. do you guys have any ideas that could help me T/s this?
I would start by listing all the test point voltages.
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Old 13th February 2018, 09:36 PM   #486
brandanbooth is offline brandanbooth  United States
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Default Here are my voltages

Quote:
Originally Posted by Botte View Post
I would start by listing all the test point voltages.
Voltages are as follows
G-t6 +30.1; g-t4- .35; t6-t7 +1.35; t6-t11 10.54; g-t18 .93; g-t14 +14.66; g-t19+8.06; g-t17 -9.27;g-t8 -30.06;g-t2 +.56; t8-t9 1.37; t8-t13 -10.15;g-t15 -14.64;g-t20-11.43;g-t16 +6.63
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Old 14th February 2018, 03:23 AM   #487
brandanbooth is offline brandanbooth  United States
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Quote:
Originally Posted by brandanbooth View Post
Voltages are as follows
G-t6 +30.1; g-t4- .35; t6-t7 +1.35; t6-t11 10.54; g-t18 .93; g-t14 +14.66; g-t19+8.06; g-t17 -9.27;g-t8 -30.06;g-t2 +.56; t8-t9 1.37; t8-t13 -10.15;g-t15 -14.64;g-t20-11.43;g-t16 +6.63
I figured it out it was my tl431 they were both fried from putting my c5 and c6 in the wrong place. On my way to having my very first amp built
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Old 14th February 2018, 04:32 PM   #488
Eric is offline Eric  United States
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Sony Vfet Illustrated build guide
Letting the 'magic smoke' out of something is a typical right of passage on the journey to your first DIY amp... Congrats to you - now it's official :-)
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Old 14th February 2018, 06:26 PM   #489
cjfrbw is offline cjfrbw  United States
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I have one of these amplifiers pre-built, but with two devices (VFET) per channel rather than the four of the circuit diagram. It has slots for the extra VFETs. I have read that the power goes up slightly and the distortion drops a bit if you use four per channel rather than two, but are there any other advantages i.e. longevity, less stress on the VFETs etc.to using the full complement of four VFETs per channel? It appears to be a drop in as long as the VFETs are matched and the board has the resistors for the extra pair. Any other precautions?
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Old 14th February 2018, 06:52 PM   #490
brandanbooth is offline brandanbooth  United States
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Quote:
Originally Posted by Eric View Post
Letting the 'magic smoke' out of something is a typical right of passage on the journey to your first DIY amp... Congrats to you - now it's official :-)
ive learned alot building it and i've enjoyed it every step of the way.

Eric I just realized that it was your website that inspired me to start doing my own builds and set me on my journey. it was your ib sub build on your website that i was going to actually build first but ended up being the vfet.
thanks for the inspiration and putting your builds out there for me to find .
Brandan
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