VSSA 50

[Lazy Cat]

Hi guys

Been busy this weekend finalizing NC1200+SMPS1200 amp, plus set the First One from being unstable to music reproduction.

 

[Holgi]

Hi guys

Been busy this weekend finalizing NC1200+SMPS1200 amp, plus set the First One from being unstable to music reproduction.

Ooooooh my eyes are getting wet... Drehkondensatoren!!! (this is what variable caps are called in German. I remember those guys being built into my very first diy radio back in the 80s).

Keep going on, I really like your builds

 

[JOHN BALI]

Lazy Cat hasn't been very lazy lately. First One SMD populated PCB (50 x 80 mm) first time connected to SMPS600 and yes it will run on +/-64 V

what is this ... ? with +/- 64v
LC what input pair you use & output only single pair, is that ok?
they must be very powerfulll
No more film caps on feedback to ground, not needed anymore?

Regards

 

[Lazy Cat]

One step beyond - First Oné

 

[BYRTT]

Hi Andrej nice and Space filled, a comming costumer wont get disappointed i he looks under the Hood.
Joke (HeHe):
"VSSA in Lakner One chasis" = Amplifier with built in Power supply.
"First One in Lakner Two chasis" = Power supply unit with built in Amplifier.

JOHN BALI post 43 look at new image smd bypass caps under pcb for 22oouF FC elko.
BR Ricky

 

[woofertester]

Hello LC

Will First One be 200W into 8 ohms? Is it DC coupled as you discussed earlier in the thread?

Will you be offering a GB or selling the First One as a commercial product?

I have a friend who wants a DC coupled amp of high power. He and I are discussing some loudspeaker measurements that require a DC amplifier.

In the SSA thread you mentioned someone may want global current feedback. Have you tried placing a resistor between the amplifier + out and the speaker and moving the amplifier feedback to the junction of the resistor and speaker? I will be trying this with a VSSA and SSA PCBs that I am in the process of building. This should turn the VSSA into a Howland Current Pump.

It wold be helpful if the First One has a jumper that can be removed so that the feedback point of the amplifier can be moved from where it is now to the junction of a series resistor between the amplifier + out and the speaker.

 

[31697B]

I find, for my needs, that I need 200-250W/8 for the efficiency of the speakers and room volume/size, SPL. Minimum.

Do you have test equipment to do IM/THD et al tests on the finished product? PM me if you need some testing done.

Thx-RNMarsh

 

[metallicus69]

I find, for my needs, that I need 200-250W/8 for the efficiency of the speakers and room volume/size, SPL. Minimum.

Same here! I feel that a bridged/balanced stage would be better though than increasing the voltage and number of output devices.
As the summer will slowly fading away, I might find more time for experiments in this area.

 

[Idefixes]

Last monday i apply the diode/10R mod on my LC_VSSA modules. As they yet perfectly sound to my taste...For more flexibilty toward the speaker nature i'd like to have more power i remerber me the first VSSA iteration. One vssa limite toward Vdc rail amount is the Jfet CCS that have Vbr limited to 40V. As i didn't find , up to time, i another jfet with more suited Vbr i replace the Jfet ccs with the bjt-ccs that act in BG1/Versatil. If some experts can take a look at this point to validate? I swap too from ALF16 to 2 Renesas output pair as they are more purchaseable....See schematic and layout under. The board is design to be mount on heatsink with only 75mm height as FISCHER ELEKTRONIK SK56/75/SA.

Marc

 

[JOHN BALI]

Hi Marc,
I'm waiting the progress
the 22pF compensation caps maybe need higher value.
(I was use 22pF before but I also use 0.22 ohm source resistor)
My double output(J162+K1058 too) not stable yet & no CCS too...
That transistor CCS I should try to apply there, thanks
you give me some idea...

Regards
John

 

[PMI]

Last monday i apply the diode/10R mod on my LC_VSSA modules. As they yet perfectly sound to my taste...For more flexibilty toward the speaker nature i'd like to have more power i remerber me the first VSSA iteration. One vssa limite toward Vdc rail amount is the Jfet CCS that have Vbr limited to 40V. As i didn't find , up to time, i another jfet with more suited Vbr i replace the Jfet ccs with the bjt-ccs that act in BG1/Versatil. If some experts can take a look at this point to validate? I swap too from ALF16 to 2 Renesas output pair as they are more purchaseable....See schematic and layout under. The board is design to be mount on heatsink with only 75mm height as FISCHER ELEKTRONIK SK56/75/SA.

Marc

Very, very nice layout Marc!...

 

[Idefixes]

Thanks PMI. Here the layout version for TO264 double die...

 

[PMI]

Thanks PMI. Here the layout version for TO264 double die...

So this part is not readily available in Europe, either? That is disappointing. I found a few in stock in the US, but I was under the impression you can get it in Europe more easily, probably because the Alfets in general, are marked "UK stock".

 

[Idefixes]

So this part is not readily available in Europe, either? That is disappointing. I found a few in stock in the US, but I was under the impression you can get it in Europe more easily, probably because the Alfets in general, are marked "UK stock".

ALF16N16/20 and ALF16P16/20 are available from Newark french webshop (called Farnell), but they are quite expensive : about 14€/u

Marc

 

[gaborbela]

Please check out Exicon at Profusion.
Good quality also.
Greetings Gabor

 

[Idefixes]

Please check out Exicon at Profusion.
Good quality also.
Greetings Gabor

Exicon double die version seem out of stock for a while, i look at profusion as they were a little cheaper as ALF ones..
For TO264 version i need to place the external diode latfet protection

Marc

 

[gaborbela]

Thanks PMI. Here the layout version for TO264 double die...

With these circuit (post 52) can we use 50V rail voltage if we use BC550C/560C?

Greetings Gabor