Success ! After being put back on the right path I was finally able to bias up the front end and hit 70 MV offset ( t18-gnd). Very twitchy pots, it might have been a bit easier with 25 turn pots instead of the single turn ones though, but now the job is done. Hopefully I'll find time this weekend to install the VFETs and finalize things. I'll go dig out some cheap speakers for the maiden voyage.
Paul
I have tried both multiturn and single turn pots and much preferred the single turn. It is touchy with either one and easier to me with the single turn. I am now rebuilding my SE BA-3 amplifier with boards I removed years ago and much the same procedure of biasing and zeroing dc offset is involved in the BA-3 front end board. Anyone who has built the BA-3 preamplifier will be familiar with the procedure.
Do you think these would be ok?
http://au.mouser.com/ProductDetail/...Q1uosSi9M7vwsbcYtHmqDh/JqXIhhEIp1FjYMB70fGQ==
Yes but only 3 pcs in stock today. Papa use 4 x 15000 uF and is sufficient.
All caps 35 V | 15 000 uF or biger capacity ( 22k or 33 k uF )
and higher voltage are ok if they are 35 mm diameter version for DiyAudio Store universal psu pcb´s.
http://www.mouser.com/ds/2/88/SLP-15028.pdf
http://www.mouser.fr/Passive-Compon...4atvZ1ypb2ikZ1yx4avv&Keyword=22000+uF&FS=True
I do solder Cornell Dubilier on Vfet CSX1 boards filter psu last days that industrial nice quality caps imho.
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Thats one dangerous amp 😀Success ! After being put back on the right path I was finally able to bias up the front end and hit 70 MV offset ( t18-gnd).
Looks a lot like http://origin.dastatic.com/forums/gallery/data/2163/medium/AL_Nelson_mods-CB_mods_VFET-2_3.png from http://www.diyaudio.com/forums/blogs/tea-bag/352-sony-vfet-version-2-al-boards-build-blog.html which is kind of a consolidated version of the initial pt. 2 circuit and the official DIY version.
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yeah, it´s the frontend from Sony VFET R0 and the outputstage of the Sony VFET part 2 with the new values. Only R24 and the feedback are different.
Looks excellent! Warms my heart when the Universal Mounting Standard helps with this sort of thing.
Guys me and ceevee have missed the 3rd batch as I took a few extra hours to order for both of us. If anyone has 2 essential kits and has decided to not go ahead with this project please let us know and we would very happily buy them.
Manuel
Manuel
Nice build! Excellent documentation/measurement charts at your link. I just scribbled numbers on the build guide, but populating tables like you've done is the way to go for a methodical progression.
BK
Hi, great build, great documentation! Thank you.
Would you mind telling me about your front mains switch?
Cheers
Ernst
Indeed excellent documentation and pictures, you sure know how to build an amplifier 🙂😀
Very very nice!
You have listened to many good amps now, which do you like the best?
Very very nice!
You have listened to many good amps now, which do you like the best?
Thanks guys, and most importantly thank you Nelson, I wouldn't have done it without you
😀
So far my absolute favorite amp was Aleph J. I haven't had a chance to listen to VFET properly yet, but I have a strong feeling that I may like it even better...

So far my absolute favorite amp was Aleph J. I haven't had a chance to listen to VFET properly yet, but I have a strong feeling that I may like it even better...
Hi, great build, great documentation! Thank you.
Would you mind telling me about your front mains switch?
Cheers
Ernst
Thanks. The mains switch I used is this one: http://www.mouser.co.uk/Search/Prod...irtualkey69300000virtualkey693-1241.6821.1120
,Thanks. The mains switch I used is this one: http://www.mouser.co.uk/Search/Prod...irtualkey69300000virtualkey693-1241.6821.1120
Hi Qwertyl, I was looking for a switch like ths that is a switch, not only a push button without switch, and this is it. Thank you!
Cheers
Ernst
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Buzz
I have and interesting issue.
I have buzz in the amp when the inputs are connected.
With no inputs connected, it's dead silent.
With one channel connected, it doesn't matter which one, dead silent both channels.
With the inputs connected together, not to a preamp, Buzz.
Any thoughts?
Thanks,
I have and interesting issue.
I have buzz in the amp when the inputs are connected.
With no inputs connected, it's dead silent.
With one channel connected, it doesn't matter which one, dead silent both channels.
With the inputs connected together, not to a preamp, Buzz.
Any thoughts?
Thanks,
Hi Gents,
just did quick search on the thread and found nothing about any possibility to order v2 PCBs (more power - with two pairs of VFETs). I would appreciate any help or link.
just did quick search on the thread and found nothing about any possibility to order v2 PCBs (more power - with two pairs of VFETs). I would appreciate any help or link.
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