Simple Symetrical Amplifier

[Lazy Cat]

Shouldn't there be at least 7 pins for audio input, output and power supply?

No, it is integrated BIGBT part with three pins:
- gate
- emitter (source-collector)
- collector (drain-emitter)

Included are one mosfet driver, two bipolar (NPN-PNP) outputs, few resistors and gate protection zeners.

 

[Lazy Cat]

Very cool Kind of "huge transistor"

I'll use them in best proposed CFA schematic.

There's enough space inside to replace IRF with ALF.

 

[bimbla]

Another Symmetrical Amplifier

Hello Lazycat and all,

I have posted another Symmetrical Amplifier here:

http://www.diyaudio.com/forums/solid-state/262575-distortion-hates-symmetry.html

However, unlike some brilliant brainstorming that has been going on here, mine is a small modified version of an existing work by Elektor.

Kindly take a look. Hopefully it will being out more/better ideas.

Thanks!

 

[Lazy Cat]

Thanks for invitation but my thread is about CFA not blame/CFP, which was erased from my preferred list long time ago. Eventually your amp would operate but first you always have to ask yourself a question: what would I like to achieve by specific schematic, is it a footprint, sound quality, THD, universal usage, power ... There's no best amp on this world, just optimal implementation for certain purpose-need.
Just go and make it real, L.C.

 

[bimbla]

CFA

Hello Lazycat,

I agree to what you say 100%.

The two topologies are totally different. CF needs lot more design skills, I guess.

Have you ever planned to write design notes for the SSA in this thread. That would be invaluable for so many of us here.

Thanks!!

 

[guitar89]

Sorry to mention this picture from long ago, now I have interest in Headphone amplifier now ( DIY style ) The first one that pop up is SSA ~

According to Post#1429 It uses quite complex (in terms of component numbers) and also involve non-BJT that i'm not familiar with, it is possible to modify the output and input slightly, so most of it remain BJT ? (which i have also abundant)

Plan to make it ��+-5V which easily power up by alot sources, instead specific power supply. It will also be lower-powered (within 10W)

 

[franziscko]

Hi my friends! Can someone link the page of last and stable circuit and PCB?? Thanks!!!

 

[AndriyOL]

Hi guys

Finally, I am proud to announce that the SSA Low Impedance HP design project is prepared. It was a DIY community mutual project since there are ideas, knowledge, effort and of course time & energy of many involved, to offer free SSA amplifier project to all interested.

Happy DIY, enjoy, regards Andrej

P.S. Special thanks to Alex, you're the Man.

http://www.diyaudio.com/forums/solid-state/193923-simple-symetrical-amplifier-118.html#post2755474

Could someone share a list of required components for this amplifier, building specifics guide?
Also what needs to be changed for only 3 pair of output devices and 35V rails?

Many thanks in advance.

 

[AndriyOL]

Hi Smiley
I didn't forget about balanced SSA HP V12, it will be updated with all the latest upgrade details and small improvements from the real circuit. So I kindly ask you to wait a little more until a base core of the SSA will be up to the highest performance level as expected.

Hi all and LC.
Just curious, was balanced SSA HP V12 updated or did I missed it somewhere in the thread?
Thanks and Regards.

 

[AndriyOL]

SSA HP PCB layout. Holes in the output\gnd zones needs to be corrected manually, due to layout software limitation.

 

[maxlorenz]

Epiphany's night.

I did not found VSSA's thread so I post here.

Dear LC, guys,

What if?
Most good things begin with this question.

What if if we combine one the best simple amps available (thanks to LC's generosity), the VSSA, and one the best amplifiers ever made, Sony TA-N7?
VSSA is "fast" and TA-N7 uses VFET in cascoded output, and both are "fast ".
I bought some NEC VFETs and want to try the cascoded output.
First I modded a BJT VSSA to a cascoded output with very old 2N5883/5885 transistors (gift) and NOS 2SK1173/2SJ473 low power transistors, to experiment and learn.

Please study cascoded ouptut theory from the net. I am not good enough to teach you. Briefly, there are many excellent improvements to be expected and, as any good society, both transistors mutually "protect" each other. Plus, when using VFET, apparently we can have a sort of automatic biasing, apart the protection, in which the low power device "sacrifices" itself in case of trouble.

The results of cascoding the VSSA output are astonishing to the point of absurdity. That was clear to me from first notes yesterday. The most open amp I ever heard...see: no matter how good is the CFA amp, the output devices will always limit the transparency. I imagined the way to go was this cascode-VFET solution, but the BJT-cascode is not bad at all!

Though I am still experimenting best bias, best connections etc. I cannot imagine how good it will sound with VFET, the superior transistor.

I will now "cascode" all my outputs from my different amps. I recommend that you experiment with this mod.

 

[AndriyOL]

Schematic?

 

[maxlorenz]

If I recall well...

Apparently you can connect Vbias for the cascode (common base BJT) to ground OR to the output node, but I did not tried this yet.
Besides, it is supposed to be "AC ground", with a cap (didn't try it yet), but it works like it is now and most schematics available for free do not include a cap, so I assume this provides "AC grounding"... I've researched for the theory behind "AC ground", unsuccessfully, so I would appreciate enlightenment from the gurus, on that subject, or in relation to any other aspect of the problem for that matter...

Apart from this mod, this cascoded output VSSA differs only in one aspect compared to my regular BJT-VSSA: one extra // 0u25 Russian polystyrene cap on the FB path. This caps improve things wherever I use it.

Cheers,
M.

 

[AndriyOL]

ussr teflon caps ft-3 are better than any of their polystyrene

 

[AndriyOL]

Requested by many, SSA BIGBT HP, SSA CCS schematics and final product successfully made in June 2012

Hi LC.

Why the components on PCB differ from the schematic?

 

[maxlorenz]

Hi,

I would also like to have a pair of SSA BIGBT PCB to build a cascoded version instead of an original version...

See, my cascoded BJT-VSSA (posted above) has now +/-6VDC only for the "cascoded transistor" (the rest for the "audio" transistor) and it sounds wonderful to me.

So, the next step is a high voltage all cascode version.

For the record, I also cascoded the outputs of my BLAME ST from Destroyer X and I got the same increase in transparency and dynamics.

 

[padamiecki]

Hi!
did you check stability/oscillations isuues?

 

[maxlorenz]

Thanks Padamiecki for your interest.

I checked mainly for power headroom and a short test until 20KHz with the VSSA, which is not in a proper case yet. I plan to test it further and maybe add Zobel network when "casing". Both amps run cool with low bias and sound nice to me, without any strange noise.
Only the VFET amps have more transparent sound than these. Actually, I also want to build cascoded VFET amps...

Regards,
M.

 

[padamiecki]

Probably you do not have stability issues because you reported good sound...

 

[Phil Bill]

Thank You LC for Yours time and great generous will & advising all of us to follow the right Starr . . .
I implement all the suggestions You mention and I just proceed to some first beta smelling taste of SSA.

I wish You a nice Music Enjoyment times with Your nice Christmas gift . . .

Hi,
I wrote you on the ''Private message'' but maybe you don't check often there your messages that's why I'm asking here if you have built your schematic and if ''yes'', please share your sound impression with me because I like it and I want to build this amp, with your permission, of course.
Thanks for your answer! Best regards,

Horia.