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

[e_fortier]

Hi Vunce,

Cool trick, works like a charm 👍

The cone still moves a few mm but it’s very smooth, not harsh at all for the driver...😀

I think I’ll remove my switch and install a fuse holder instead...maybe...

Thanks again
Eric

 

[Vunce]

👍🏻👍🏻👍🏻😉

 

[ra7]

So, I got to hear a SIT-4, which is a Tokin amp in common source mode (i.e., it has voltage gain too). Absolutely glorious sound. I want to hear it in the TDV chassis. It should be relatively easy: just put the choke on the drain pin and apply a little feedback.

Ben has reported that he prefers his followers to CD mode VFET amps. For sure, the follower will have less distortion, but the SIT-4 has such a glorious sound that it will be worth the experiment.

 

[Zen Mod]

choke in drain must be of exquisite quality

 

[ra7]

Agree, but I am going to stick in the Hammond 193V and see what happens. That's all I have. It is big, but you can hear its limits when pushed, especially at the top and bottom ends, even in SF mode.

What's your recommendation for exquisite quality choke, choky?

 

[Zen Mod]

I'm on wrong side of Big Pond, to give you any advice

Besides having lesser knowledge of commercial availability than some esteemed members here

 

[ra7]

It is Hammond or wind your own, as far as I know. Then there are boutique shops in Europe and Asia.

 

[nicoch58]

on your side Dave Slage .....

 

[rickmcinnis]

I asked Slagle if he would make something for these amplifiers when Ben Mah's posts were made. He said yes and then I never heard back. I did ask him an additional few times with no response. I had bought more than a few pieces from him so he should have known I was serious. Who knows?

I am using the Lundahl filament choke - and having nothing better to compare it with or being able to take measurements, I am able to be blissfully pleased and ignorant of misbehavior that I cannot hear.

It would be fun to hear what they could make with their larger cores. Maybe they would consider an order if there was enough interest for a small run. Who knows what small would have to be?

Maybe Slagle would consider making a small run? I would want them.

 

[ra7]

I’d be in on a pair Rick.

 

[Nelson Pass]

So, I got to hear a SIT-4, which is a Tokin amp in common source mode (i.e., it has voltage gain too). Absolutely glorious sound.

Here is a photo of the stack we listened to. Bottom 2 are Tokin SIT prototypes, middle is SIT4 proto,
above that is small version of Beast w/ 1K Jfets, top is ACAmini.

 

[Zen Mod]

and where are my Tannoys?

without them as reference, no good future amps ........

Bottom 2 are Tokin SIT prototypes

don't know anything about these .......

 

[ra7]

 

[ra7]

The Cube Audio full rangers proved pretty revealing.

 

[von Ah]

TDV back in rotation in the Scryer-dominated-world of my main system. 😎
This the first time I’m hearing it paired with the Iron Pre. Very nice match.

 

[ra7]

Iron is good

 

[manniraj]

My progress so far and I went with suggestions from ra7, CodyT and Eric looking at my parts bin what I could find to meet the schematic. Used 22R, 6.8k and then 2.2R *2 for R3. Will solder a 220/3w resistor across the spk+/- as per the original schematic instead of 470/3w suggested as I have these resistors with me.
Will be using 2 of the 4.7uf film caps and then a 18v zener diode. I am going to repurpose the 193T from the LU amp as well as the 24v 5A smps along with the Tuba filter

 

[manniraj]

Done with the boards except for the zener diodes.

 

[manniraj]

Ok got the 18v zener and powered up one channel with a 2.5A fuse as Eric suggested. No magic smoke and voltage across the biasing resistors parallel 2.2R is 1.925vdc after about 7-10mins. Around 1.75A bias rather than Eric suggestion of using 1.6A bias.

 

[Zen Mod]

Ok got the 18v zener

what??!!