Total Domination VFET (TDV) Amp (using 2SK2087C)

[codyt]

There's something especially satisfying about the lack of parts in the circuit. Amazing what a couple of resistors, a SIT, and a choke can do!

 

[Zen Mod]

chokes are for Weaklingsesss

SITs too

 

[codyt]

Okay, so if you measured 1.6V across 1R then the bias is 1.6A. You could go higher if your heatsinks allow. How does it sound?

So your r3 dissipation is 1.6A*1.6V=2.56W. I would just keep an eye on R3 for heat and long-term reliability (didn't see the size of sink you used – you may be plenty fine)

 

[codyt]

chokes are for Weaklingsesss

SITs too

No, square law DEF amps are WEEEEAAAKKK

 

[von Ah]

2SK77Bs are for losers. 😉

The R3 sinks are small aluminum ones for TO220. They should suffice. I included a little Keratherm on them.

 

[von Ah]

On that note, it might be feasible to mount such power resistors to the big heatsinks. However, that would require drilling into the sinks again. Not pressing my luck there, either, since my last foray put the Tokins so far south they’re wearing shorts and flip flops.

 

[ra7]

There's something especially satisfying about the lack of parts in the circuit. Amazing what a couple of resistors, a SIT, and a choke can do!

I really like this aspect too. It really makes you want to build it. And it sounds damn good.

 

[Jerdy]

I opted to go with 2.5R 10 Watt chassis-mount resistors for the bias. I originally had paralleled two 4.7R 5W resistors but the current sharing was unequal and resulted in one resistor getting wildly hotter than the other. With 1.4A bias the resistors dissipate about 5W, which is well within the unmounted limits of the new resistors. This is for the 2SK180.

 

[ra7]

Nice! You could bias higher if heatsinks allow. 2sk180 is capable

 

[rickmcinnis]

With people paying silly prices for fuses - I just noticed these.

Tin plated copper leads instead of the steel caps and likely steel ends on the holders.

A small thing but easy to implement and should to superior to the typical fuse and holder. Not as easy when they blow - maybe to be inserted after the amplifier is sorted.

The link is to the product page at Mouser https://www.mouser.com/datasheet/2/240/Littelfuse_Fuse_396_Datasheet_pdf-794765.pdf

$1.36 each for ten at a time.

 

[e_fortier]

These fancy fuses are usually not CSA/UL therefore your unit is not well protected and can become a hazard. You are better off using regular certified fuses.

 

[ra7]

It has a UL mark and a PSE mark (Japan). So, should be safe. But good to check. No CSA listing.

Very interesting product and might be a great addition to the drain of the VFET for overcurrent protection.

 

[e_fortier]

My comments was for the fuses some manufacturers sell for $30 per fuse and are so called audiophile type.... this is a gimmick.

 

[ra7]

Yeah, those are bogus. There are some costing more:
https://www.partsconnexion.com/FUSESRBL-83101.html

 

[e_fortier]

OMG, you just made my day !
The people writing stuff about these fuses are too funny (I’m being polite) see below...

 

[pinholer]

Must be DC fuses.

 

[e_fortier]

Lol..😂

 

[Zen Mod]

after 300 hours I can remove shorts from amp speaker outputs, and start listening?

 

[von Ah]

😆

No smoke = no silence with my builds. Test speakers go right up if I haven’t burned anything.

 

[rickmcinnis]

So LITTELFUSE is a suspect manufacturer of fuses? How do these fuses have anything to do with ORANGE fuses, and the like, which have the same steel end caps as regular fuses?