Sony vFET Illustrated build guide

[manniraj]

I always wanted to go with true dual mono build for my Sony VFET, hence built couple of universal PSU boards but because of space constraints in the cabinet I had to go with a single toroidal with 2 secondaries of 0-22v@6.8A x2 which is the recommended as per the build guide and NP. But couple of weeks I have connected my another same universal PSU board with the same exact components and the amp works fine and better control on the bass but the downside is the hum issues that cropped up with running dual PSU boards with single toroidal. I was suspecting it would have similar issues that I encountered with my earlier CRC psu boards for the PeeCeeBee V4 build.

So now planning to get a new single toroidal with 4 secondaries like 0-22v@4.5A x 4 so effectively comes to around 400VA. Planning to use 4 independent bridge rectifier modules for 4 secondaries to power 2 universal PSU boards. This is the ideal rated toroidal that multiple of my friends suggested but I just want to double confirm here before I go ahead with the ordering. As I said above because of the space unable to go with 2 independent toroidals. But at least with 4 secondaries I can still achieve sort of dual mono

thanks

 

[PJN]

AHHH, similar the the BA3 deal when substituting those pieces. I think I have sufficient pieces for this project without going to the Fairchilds. I have several projects, mono Block BBA3 amps and a few others I obtained them for. Otherwise i will use Fairchild and adjust pot value as you say.

Thanks for the BOM, I can now start a parts box. Did you use the 4U or the 5U chassis?

Russellc

Hi Russell,

I used the larger 4U chaszisy, 400 mm deep I think, and was glad for the extra space. Once I stuffed in a 400 va torroid, soft start, psu, ect, thinks started to get tight.

 

[Russellc]

I bought them from ebay.
Nylon/ABS Round Spacer, Not-Threaded, for M3 M4 Screw, ID3.2 / 4.2mm | eBay

Wow, I thought they were sockets, 4.2 is appropriate length?

Thanks for the info & link.

Russellc

 

[Russellc]

Strange. Anyway, it's post #2766 by Variac in the "Sony VFET Amplifier Part 2"
thread. It's a pdf attachment called "VFET Supplemental BOM Store.pdf"

Thanks...

Russellc

 

[cosmo61]

Wow, I thought they were sockets, 4.2 is appropriate length?

Thanks for the info & link.

Russellc

The socket (t-bar) is 4mm. The nylon spacer length i use is 4 mm, 4.2 ID is the inner diameter for m4 screew, 3,2mm is for m3 etc.
If i remember correct OD ID 5mm 3,2mm length 4mm.

 

[Russellc]

The socket (t-bar) is 4mm. The nylon spacer length i use is 4 mm, 4.2 ID is the inner diameter for m4 screew, 3,2mm is for m3 etc.
If i remember correct OD ID 5mm 3,2mm length 4mm.

Thanks again!

Russellc

 

[delecoy]

I used the 4U for mine. Wasn't too hard to fit everything in. It runs way cooler than my F4, which is also in a 4u

 

[Biosonar]

Another DIY VFET lives:

 

[Soundhappy]

@ Biosonar
Great nice "clean" quality DIY build congratulations

 

[WalterW]

Very nice build!
Which rectifiers did you use?

Blue LED needs a higher value resistor

 

[WalterW]

I always wanted to….

Hi manniraj, Love your frontpanel with those VU-meters and CNC work!

 

[manniraj]

Hi manniraj, Love your frontpanel with those VU-meters and CNC work!

Thanks Walter, it looks and sounds wonderful. The best amplifier that I have made and also heard. It pairs superbly with my Jericho Horns made from Fostex 208Sigma drivers. That is why planning to go with dual mono PSU boards and as no space inside the cabinet going with a single transformer but with 4 independent secondaries. I am using 2 psu boards now but as usual having hum issues.

 

[mr_whocares]

isolation for FQP3N30 and FQP3P20

hi all,
it seems that the rear metal plate of the TO-220 packaging of the FQP3N30 and FQP3P20 is not connected to any of the transistor pins and thus, no need for a mica isolation to the heatsink. is that correct or should one uses an extra insulator ?

thanks and regards

 

[Gyuri]

You must check it again.

 

[Rodeodave]

You will find your answer in post #2.

 

[Gyuri]

To be more precise:
"If your mosfets have an exposed metal tab then you'll need a small plastic sleeve for the holes and an insulator. These sleeves are supplied in the supplemental kit along with TO-220 mica insulators which require grease on each side."

 

[mr_whocares]

many thanks, gentlemen, for the replies!

i will follow your advices, however, foregive for my ignorance, but why use an insulator if the metal tap is not connected to any pins of the FQP3N30 or FQP3P20?

 

[Dennis Hui]

I just checked an FQP3P20 and the metal tab is connected to the drain (middle) pin.

 

[6L6]

Dennis Hui is correct. Insulator required.

 

[mr_whocares]

Dennis Hui is correct. Insulator required.

dear hui, dear 6l6,
many thanks for the clarification! (please help a blind man and tell me on which page it is mentioning that the metal tap is connected to the drain :-(
http://www.mouser.com/ds/2/149/FQP3P20-109276.pdf )

thanks gentlemen