[Huskerbryce]

The Vfet is not mine.  It belongs to my friend.  He has many many boxes of nelson pass amplifier parts/kits in his basement.  We brought this one up today and did some bourbon and some music with it.  As far as what is under the hood, I will find out when I can.  Short answer is I dont know.

[Huskerbryce]

Sweet!  So that is yours?  Is that an N-Channel?

So I just found out that “Yes” it is an N channel.  He also has a P channel one.

[jmimac351]

Well, I managed to find another Sony VFET Anniversary amp.  N-Chanel and FE2022 input board, exactly like my other one. 

The cool thing is how you can wire it for mono...easily.  Y adapter to the inputs and just strap the + POSITIVE terminals together, as pictured.  I ended up doing both without the negative binding posts strapped, since the negative posts are already ground together inside the amp.  I bought some cheap adapters to test this with and will end up making some custom ones.  I have Jupiter tinned copper wire on the way, and will be working on how to replace my interconnects, for a fraction of the cost - and better sound.

This VFET amp is from another of the guys who write the amplifier build guides for the projects Nelson comes up with.  So, both VFET amps I have were built by the guys who write the guides themselves, so I know they are "perfect".  I should have zero issues. 

I'll tell you how much I paid for these... 900 bucks each.  I share that because you'll never be able to buy them from me.  With Nelson's DIY stuff, it is just not really necessary to spend a ton of money on amps, unless you want The Real McCoy for First Watt. 

This stuff has been an absolute revelation.   

[Jaytor]

I don’t think you have the speaker outputs connected correctly. If you have the positive phase corrected to one input and the negative phase connected to the other, you want to connect the positive speaker wire to the positive terminal of the channel that is connected to the positive phase of the balanced connection, and the other speaker connection to the positive speaker terminal of the other channel. The negative speaker terminals from both channels are connected together as you have them.

This is known as a bridge tied load.

This kind of connection can only be done with amplifiers that are not already bridge tied loads which generally means the negative speaker terminals are connected to signal ground.

[jmimac351]

I don’t think you have the speaker outputs connected correctly. If you have the positive phase corrected to one input and the negative phase connected to the other, you want to connect the positive speaker wire to the positive terminal of the channel that is connected to the positive phase of the balanced connection, and the other speaker connection to the positive speaker terminal of the other channel. The negative speaker terminals from both channels are connected together as you have them.

This is known as a bridge tied load.

This kind of connection can only be done with amplifiers that are not already bridge tied loads which generally means the negative speaker terminals are connected to signal ground.

https://www.diyaudio.com/community/threads/diyaudio-25th-anniversary-vfet-special-offer.429405/page-7#post-8145774

[jmimac351]

Below is from the F4 manual and referenced as the way to do it.  Nelson confirmed separately this same way when I inquired about whether the First Watt SIT-3 amp can be run as a monoblock. 

This mentions an XLR but I am just testing with just a cheap-o Y-adapter for the RCA into both inputs.  It's working and they sound great.

[Jaytor]

Ok. I was assuming you were trying to get more power into a typical 8 ohm load. With a current amplifier, you can connect then this way to get more current output.

[jmimac351]

Ok. I was assuming you were trying to get more power into a typical 8 ohm load. With a current amplifier, you can connect then this way to get more current output.

Thank you for looking closely at it.  There was a fair amount of confirmation to make 100% sure it was correct... with those VFETs...