Article - Sony VFETs part 1

[Soundhappy]

everything is better , after some time .

and some wine

And bad without it!

Oh search for grand cru Vfet sound for my ears yeah
2SK82\2SJ28 was in long sleep and dreaming 😴 be soldered

😀

 

[juanitox]

Hi Juanitox
Congratulations for nice CSX1 built !
Not doubt You are balanced XLR king.
Want ask You and Diyers about resistor in signal path are they become hot ? Are in this point benefit for sound if choice of more watts model ?Speakers protection influance Vfet´s outputs sound much or subtly.
Speakers is precious treasures i admit anyway .
Last question is this some break in time for this complementary sit´s
sound become better after week or more of intense listening sessions ?


Greetings 🙂

everything has a sound , sure big thick film power resistor sounds different than inductive wirewound but load choke and active load are too...
speaker protection is the condom of listening you can go without 😀
( with the SITAMP you have the output coupling cap..)

Big cap take a time to break-in but don't expect miracle , better tweak operating point or loading type..🙂

 

[dady]

Something interesting, or I learning about, protection system are invisibles for the sound?

Hola Christian friend, It you have a output cap you have not DC, Maybe an overcharge system but do not need a system for protect your speakers.

CSX are DC coupled and for that reason nothing between.

I hearing for there that Juanito has monster loudspeakers, is it true?

Juanito, Dude, One more question, Do still use SE with the sj28 like ccs? What you did with the secondary connection to the gate in this Vfet?

The best for you gentlemen du le Transpirineés and course to the rest of people of this thread.

 

[juanitox]

hi , i don't have special speaker just small avant-garde horn , but i like them enough to put a speaker protection 😀

yes i continue using the CSX1 in single mode with the 2SJ28 on top of the 2SK82 . i just rewire the jensen to get the full signal only to 2SK82 gate .
and use the 2SJ28Bias to get 0v offset.. it's probably not the best way to feed the 2SK82 but sounds very good like that .. a kind of OTL single end amp...

 

[dady]

Thanks for answer to me, Juanito, the sound, how sound, with stress music, nor chamber neither jazz, I say BRUCKNER and Opera with voices, chores and complex, you have more more second harmonic because you have a Real SE. Is a complete different animal than CSX1.
The power, probably you have less than one half you can get with the pushpull system.
The other choice is, make a different CCS more powerful on step of waste a Vfet like the J28, and use over paralleling two 2SK82 for get more power.

Best Regards

 

[juanitox]

i don't listen stress music if i'm not forced to😀
i don't have CCS on top of the 2SJ28 in fact i have nothing at all ( i go unregulated) don't forget i 'm in single end and the 2SJ28 is the load!

for the power it is more enough to fleetwood mac live 🙂

 

[dady]

Hi maybe I couldn't explain well, If you keep out the 28 from the sound chain and polarize to dc = 0volt the P channel Vfet will be one CCS, controlling the current in the another Vfet, the 82.

When I ask about stress music, I am not suggesting you overload the amp. I ask about complex music with many harmonics. I guess you uses the same speakers system like the mine, horn loaded fullrange. This amp is a transconductance amps and couples very well with this kind of systems cause they are not well damped amplifiers.
I guess, sorry for the mistake if I make one, the next project with source follower will has better damping that cames from an inherent low output impedance.

 

[Soundhappy]

I remember at BAF Mr. Pass presented this CSX1
without cap and resistor in audio circuit 😀
Somebody make this experience for pure Vfet sound ?
Best regards

 

[BRUCELEY]

Hello I just saw your class A amplifiers with full range speakers sings
like angels in heaven quote. I was just writing about building soffit mount full range speakers and driving them with a class A amplifier. Please read my thread and let me know any thought s you might have about this project.

 

[vtr]

power supply question

Hi,

anyone tried a switching power supply like the connex smps300re?

Connexelectronic

i would like to test these, they are regulated and therefore i can cancel the irf-fet stabilization.

as it comes on with 4s delay (but only if fully recharged, a short on/off brings the power back instantly) my question-how long is the delay for the bias supply vs main power supply?

a normal transformer will power the bias and a delay circuit powers then the amps.

thanks for comments

 

[dady]

I just tested in a Lazy cat VSSA, It blow up instantaneously, I return for repair because they promise in paying the shipping, after that, they return the money I spend and they invite me in get another one. Poor assistance coverage. I lost some money in shipping but luckily I got a part, I lost time too.
Get a more reliable SMSP like Hypex or AP2. They are expensive but European, no risk in customs and another taxes rate.
The other, I was happy with the idea of make the amp with a SMPS, they are noisy, or you have to fix another problems with filters.
Try first in make the amp like the amp is, is critical many members have problems with heat. The schematic is to simple, a SMPS is a black box. You take the voltages but you can not make anything if something happen. You are mixing two technologies, one class A amp wasting heat and energy and other taking efficiency of 90%. Is not practical solution and is a contradictory philosophical decision
Later you can change the PS with another you are sure is trouble free. Anyway I try to make the same but first tuning the circuit like the author and many of Us did.
The best for you.

 

[vtr]

smps

thx´s but i have already 2 of this units, and with dummy loads they are fine...

I just tested in a Lazy cat VSSA, It blow up instantaneously, I return for repair because they promise in paying the shipping, after that, they return the money I spend and they invite me in get another one. Poor assistance coverage. I lost some money in shipping but luckily I got a part, I lost time too.
Get a more reliable SMSP like Hypex or AP2. They are expensive but European, no risk in customs and another taxes rate.

 

[Botte]

Progress report

Just to keep the thread active...

Here is my progress, I'm using a 7" x 13" vertical heat sink.

 

[Botte]

Progress report

Here is the inside of the power supply. The extra supply is for a LSK front end.

 

[Soundhappy]

Hi Botte

Look promising 😀
Your wood frame is good job and 12V supplementary for LSK nice !
What be finalised amp ? Keep secret ok i wait .
Good luck 🙂

 

[Botte]

Hi Botte

Look promising 😀
Your wood frame is good job and 12V supplementary for LSK nice !
What be finalised amp ? Keep secret ok i wait .
Good luck 🙂

The extra 42 volt supply is for an optional LSK front end to the CSX1. I will see how it sounds in the system and then determine if I need the extra gain to help me balance with my subs. I guess I could just turn down the subs, typical engineering, always adding complexity where it's not required. 😉

 

[dady]

Good point Botte," Adding complexity..." typical Diyaudio nerd one. I recognize myself like this kind of animal... But to late for change further my wife's requirements.
Morning Christian, Are you happy today?

 

[Soundhappy]

The extra 42 volt supply is for an optional LSK front end to the CSX1....always adding complexity where it's not required. 😉

Hi Botte

42 volts for LSK front-end ??

I remember Papa show on BAF his biampified configuration with Eminence sub woofer drive by FirstWatt amp and Lowther PM6A alnico drive with Sony Vfet amplifier. Woow i am impressed by huge long magnets like show on photo. High efficiency about 100 dB is the key.
Buffer or not , CSX1 or CSX2 , Jensen transformer configurations , many parameters to have fun.
Best regards
🙂

Morning Christian, Are you happy today?

Thanks Dady i be more happy if my diy amps are ready
but for today is work in progress. Hope you are fine too 😀

 

[Zen Mod]

,,,,,,,,, Lowther PM6A alnico ...... Woow i am impressed by huge long magnets like show on photo...........

while A in designation certainly is for AlNiCo , huge long magnets are FC , so - no AlNiCo

 

[Soundhappy]

while Ahuge long magnets are FC , so - no AlNiCo

Hi Zen Mode and Diyers

FC what is it ferrite core ?
Thanks for clarification.

Oops i see open baffle photo with Lowthers at BAF
is PM6A silver wire voice coil, ticonal magnet ?
Anyway this " jewelry " wide range speakers are not 88 dB.
Sony Vfet CSX play great with high efficiency stuff no doubt.