Live Lab Hangout #1.1 Posted

[dady]

I have gone through 15 2SK182ES from Taobao, I think they're all authentic, but the failure rate was 40% (6 out of 15 were bad).

I also notice that the refurbished ones (rust removed and electroplated to look nice and shiny) are more prone to failure, probably the refurbishing process could damage the SITs.

Don't waste the bad units, you can use them like CCS in a SE like the A3 with monster Vfet.

 

[generg]

thanks….!

the second is similar…

the third and fourth look crazy… pictures will come.

cwtim01 might be right that nearly 50% are crazy...

 

[cwtim01]

Don't waste the bad units, you can use them like CCS in a SE like the A3 with monster Vfet.

Thanks, I actually returned those bad units to the seller, so only loss was shipment cost.

Most reputable Taobao shops do allow returns, but sometimes the shipment cost is too high to justify for small returns.

 

[Soundhappy]

Christoph you are building a 1000watt SE ?

@ Diyers
First THANKS DADY for be first who bring us THF -51 sit diamonds
and thanks to Jama , Cwtim01, Generg for all precious informations with sit's curves and distortion graph's.
This evening i was thinking about Michael first presentation of Tokin
in his video and remember he say something like :
" Look it's huge twice as Sony ....we can
build with this really big single-ended amp ".
So if Sony 2SK82 vfet are " equivalent " of 300B vacuum triode
, Tokin 2SK 180/182 ES or THF-51 look like biger triodes 211/845.
Tube guys use them for 20 watts output in SE amplification and low end frequency is much better & realistic. I guess sit's can do similar score probably more always in output transformer less topology
because they are 300/500 watts disipation parts ?
Scope curves photo are 211 triode ones.

http://www.tubeampdoctor.com/images/File/ER-211 Datasheet.pdf

Greetings

Christophe

 

[cwtim01]

http://www.firstwatt.com/pdf/prod_sit1_man.pdf

Thanks generg, haven't read this manual before, will have a good read on it.

 

[Soundhappy]

@ Soundhappy, it seems you have finally collected some working 182ES,
and we look forward to your monster single-ended amplifier
(mine will be kept at 10W max, the Asian summer are too hot for anything more)

@ Cwtim01 & Diyers
Collected ES yes new batch in wait but i work
last days on metal preparations so test is next time with tracer.
Like for lot ultra-fi audio systems 10 watts are plenty this is example i am inspired
scroll to bigining if you like it :

SIT part Deux - Page 8

Curious and passionate by Tokin parameters explorations
to find other sit's side impossible to do with Sony's.

Best regards

 

[dady]

HEHE, 211 give us 30watt or more in class A2, Tubelab got 45. All this with 75 watt maximorum of dissipation in plate.
This is not possible with vfet, the curves are magnificent in some of them but no gate current neither class A2 or other supra regimen of work, I know, I know that the problem is the transformer. But there are good. I know, they have limited live but I had to replace my lowthers DX4 after 9 years because the paper cones was fatiguing. No HV with vfet but for 10 watt you have to waste 200.
Always we've compromise solutions.

 

[cwtim01]

I read Michael's L'Amp part 2 article again, and the THD @1W was around 0.1% and @10W was around 1.5%, using 2SK82.

With my 10W target, probably 2SK182ES is an overkill, so I'll try these little Yamahas - their curves look nicely linear, and I'll see how it goes

 

[generg]

I just made the same experience THD at 1W/8R is with 2SK182ES a bit higher than with SK180 in the same circuit.

Do not know why, but not important I cannot hear it……..

 

[Michael Rothacher]

In general, we find ourselves trading higher THD for more gain and vice-versa unless we get really lucky with the cancellation No free lunch as they say.

@cwtim01
Those figures were with the big air-core coil, and I think the 193V was even slightly better at 10W.

L'Amp 193V Addendum

 

[Soundhappy]

@ Cwtim01 & Diyers

Yours Yamaha curves make me thinking about Mr. Pass Sit -2
CCS topology amplifier, possibly interesting way to try
build wonder with big Tokin's or Yamaha's
Best regards

6moons audio reviews: Nelson Pass' NewWatt

 

[Michael Rothacher]

I'll check my notebook and let you know what I was getting out of them.

 

[cwtim01]

Yours Yamaha curves make me thinking about Mr. Pass Sit -2
CCS topology amplifier, possibly interesting way to try
build wonder with big Tokin's or Yamaha's

While the 2SK76 seems quite linear, it has much higher Rd and lower Gm, so it can't quite compare with the PASS part I believe (otherwise I might buy them all up from the seller )

BTW, the curves are in 1V steps, from Vgs values of 0 to -8V.

 

[Michael Rothacher]

Sorry, I forgot to check on this last night, but my recollection is that they were very similar to the Sony performance-wise. I only have one pair tho.

 

[Soundhappy]

While the 2SK76 seems quite linear, it has much higher Rd and lower Gm, so it can't quite compare with the PASS part I believe

@ Cwtim01 & Diyers

I compare them in sense of diy amp's good potential.
Anyway Yamaha or Tokins are not SIC SIT 's
modern silicon carbide semiconductors like Pass-SIT1 are right.
Sony 2SK82 CCS made by Michael look good at output frequency,
response are much linear & THD distortion are ok too...
but subjective performance was great with inductor.
Tokins & Yamaha can sound better with CCS ( sic mosfet ?)
or maybe not but this is one nice choice option
to satisfy your needs and taste.

http://www.audiohobby.com/pdf/lamp ccs.pdf

Triode guys build amps with Eimac tubes i hope build Tokin sit version
....oh is joke !

Have fun

 

[cwtim01]

Sorry, I forgot to check on this last night, but my recollection is that they were very similar to the Sony performance-wise. I only have one pair tho.

Thanks Michael, I compared the curves of my 2SK82s and 2SK76s and they're indeed quite similar, the 2SK82s have slightly more gm while the curves for the 2SK76s are slightly straighter.

I'll test the 2SK76 setup in the coming weekend, to see if I can reach the same level of performance mentioned in your article.

 

[jama]

Tracer grow up. Now I can measure vfet near operation point (4 Amp) and select them using approximate load line...

 

[Soundhappy]

Tracer grow up....and select them using approximate load line...

@ Jama

Smart work !
Perfect for distorsion autocancelation experiments
Greetings

 

[generg]

I used Mikes pictures from the 2SK182ES and made a LTSpice model out of them with his modeler ….

*--------------------------------------------------
*2SK182ES
*GENERATED BY SIT MODELER @ AUDIOHOBBY.COM
*MODEL RANGE: 80V, 2A
*--------------------------------------------------
.SUBCKT 2SK182ES D G S ; Drain Gate Source
+ PARAMS: MU=16.98 X=2.56 K=0.443 N=1.6 VCT=0 RG=2MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
*FOR MULTISIM COMMENT OUT ABOVE LINE (*) AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 2600P
CGD G D 0P
CDS G S 0P
.ENDS 2SK182ES
*--------------------------------------------------



And I have a quick and dirty circuit running with the 2SK182 and a CCS Mike suggested and the gain predicted by Spice and in reality are the same around 6.7 x or 16dB.
Means quite close to the Papa SIT (18dB).
One difference remains in my eyes the input capacity of the SK182ES seems to be two times bigger.

(around 1000pF versus 2200pF)

 

[generg]

…...compared to my balanced F4 the sound is a bit shy and soft.

After longer hearing there are qualities in the colors of the sound and the immediacy.

Bass is a bit boomy and less controlled.

Speakers are Klipsch Forte II at the moment, they are said to be at 94-96dB, but the woofer is a 4 Ohm type.
So not ideal for this SIT amp…..

Will hear longer….