too try your experimental board for me is look like building from the start sir 😀.
i just want to try lowering bias VAS....currently i'm using 32vdc supply and my VAS current reach 22mA... all getting hot
I have scaled the SSA to 60V. using higher voltage transistors...and heavier drivers..
I have made different versions .. as Nico stated the design is circular in a way that thermals in the input drives the current in the VAS/driver as well. Through house keeping with current sources, this issue has been greatly reduced.
I have made a version where i have taken the 12V cascodes away (using 80V transistors for the input) and made a current mirror into the VAS/driver. This keeps the thermal balance in the VAS very good as the current is set by CCS and mirror scale.
I have made some different outputs. from laterals to Bipolars and a combination of both.
Sound is very very good. I believe its the simplicity and short current feed-back path that plays a major role in this. Like less is a lot more. The SSA is for sure a strong concept. But it really does require some good housekeeping. This type of simple current feedback circuits benefits a lot from fixed working conditions. Simple voltage/resistor biasing is not good enough for current feedback, as the feedback currents will alter/modulate the working conditions . The current feed-back needs to be purely additive process, for this you need a good high impedance CCS driving the circuit.
I have made different versions .. as Nico stated the design is circular in a way that thermals in the input drives the current in the VAS/driver as well. Through house keeping with current sources, this issue has been greatly reduced.
I have made a version where i have taken the 12V cascodes away (using 80V transistors for the input) and made a current mirror into the VAS/driver. This keeps the thermal balance in the VAS very good as the current is set by CCS and mirror scale.
I have made some different outputs. from laterals to Bipolars and a combination of both.
Sound is very very good. I believe its the simplicity and short current feed-back path that plays a major role in this. Like less is a lot more. The SSA is for sure a strong concept. But it really does require some good housekeeping. This type of simple current feedback circuits benefits a lot from fixed working conditions. Simple voltage/resistor biasing is not good enough for current feedback, as the feedback currents will alter/modulate the working conditions . The current feed-back needs to be purely additive process, for this you need a good high impedance CCS driving the circuit.
dear Salas and Shaan,
channel 1 done, current feed change by paralelling 3k3 || 2k4.. Vas current down to 14.2mA 🙂
channel 1 done, current feed change by paralelling 3k3 || 2k4.. Vas current down to 14.2mA 🙂
Last take is 196W in 8-ohms.. Its getting better too...🙂 no DC drift and more sparkle like in your TSSA...but huge power, like it's limitless (you know the difference).
No I run it on slightly higher rails.. my output looses some voltage, so separate ralis is not needed...a diode and good caps makes it sag free...🙂
Nice. I am about to make an integrated that settles at 120 - 150watt. But it Will get a dlna interface, USB, spdif and of course analog interface.
I do not Think i get permission to ADD "made for i*****" from Apple
But a High performance docking station "Mfi" with dac and discrete opamp 😀 Will be made.
I do not Think i get permission to ADD "made for i*****" from Apple
But a High performance docking station "Mfi" with dac and discrete opamp 😀 Will be made.
AppleTV will provide you with Airplay as well as optical out, at 100$ you don't really need any docking station...just good DtoA...🙂
No, that is correct.
But it Will have a lot of jitter you need to attenuate. In my solution the Dock Will have a reference clock right after the USB interface .
Yes you Can use airplay. No problem, but if you live in a neighbourhood with a lot of wireless networks. Loss of packages Will be a problem.
Apple also have the format alac that is lossless.
But i Will stop now as this belongs in another forum.
But it Will have a lot of jitter you need to attenuate. In my solution the Dock Will have a reference clock right after the USB interface .
Yes you Can use airplay. No problem, but if you live in a neighbourhood with a lot of wireless networks. Loss of packages Will be a problem.
Apple also have the format alac that is lossless.
But i Will stop now as this belongs in another forum.
Apple is about easy of use not so much quality.... surely you can reclock the optical input as well... 🙂
I agree another forum...This is for SSA... and spin-offs.
I agree another forum...This is for SSA... and spin-offs.
more powerfull...
does my SSA have been breakin?... the sound more smooth and more relax.🙂
Shaan, does your servo version as you want to build is like peeceebee servo that you've posted earlier?
Hi,
I've been watching this thread for a while and started working on my version of SSA based on post 347. I've a big 1.8KVA powersupply which will provide +/- 78V unloaded. I'd like to use Vfets at output simply because i want to find use for some of these Fet's found in my parts bin. Consequently i'd like to use Laterals for drivers, to provide suffiecient current to charge / discharge input capacitance of these Vfets. I've sucessfully used this setup in another amp which i've made about 2 years ago. I've learned somewhere else from this thread that the PSRR is not great with this kind of topology and hence i've added a Cap multiplier at the rails to power input stage.
The amp performs brilliantly in simulation. The THD20 is less than 0.015% near clipping at 4 ohms. The square wave response is good, clipping action is excellent without any clamping diodes, etc. Now the question is will this circuit work...?as shown. comments please....
I've been watching this thread for a while and started working on my version of SSA based on post 347. I've a big 1.8KVA powersupply which will provide +/- 78V unloaded. I'd like to use Vfets at output simply because i want to find use for some of these Fet's found in my parts bin. Consequently i'd like to use Laterals for drivers, to provide suffiecient current to charge / discharge input capacitance of these Vfets. I've sucessfully used this setup in another amp which i've made about 2 years ago. I've learned somewhere else from this thread that the PSRR is not great with this kind of topology and hence i've added a Cap multiplier at the rails to power input stage.
The amp performs brilliantly in simulation. The THD20 is less than 0.015% near clipping at 4 ohms. The square wave response is good, clipping action is excellent without any clamping diodes, etc. Now the question is will this circuit work...?as shown. comments please....
Hi Magna. 'been watchin' ya... 🙂
Welcome to the SSA thread.
I can't check your schematic from where I am right now but if you have gone through the thread then you know that everyone who attempted the SSA has been successful in building it and are enjoying music everyday with it. They shared their experience/experiments here which has enriched the SSA thread with valuable amplifier-building information and many different versions of "simple" symmetrical amplifiers with the SSA front end, making this one of the threads with most diverse ideas and possibilities. If your experiment is successful then it will be a new dish on the SSA menu, specially for lucky guys like you with VFETs in their kitchen. All the best.
Looking forward...
shaan
edit: please upload a picture of the schematic. thanks.
Welcome to the SSA thread.
I can't check your schematic from where I am right now but if you have gone through the thread then you know that everyone who attempted the SSA has been successful in building it and are enjoying music everyday with it. They shared their experience/experiments here which has enriched the SSA thread with valuable amplifier-building information and many different versions of "simple" symmetrical amplifiers with the SSA front end, making this one of the threads with most diverse ideas and possibilities. If your experiment is successful then it will be a new dish on the SSA menu, specially for lucky guys like you with VFETs in their kitchen. All the best.
Looking forward...
shaan
edit: please upload a picture of the schematic. thanks.
Soundwise I don't know, but pretty close I guess.
Technically Nico's has higher bandwidth than mine(probably a megahertz higher) and has higher slew rate. But has lower PS voltage limit.
My version is inspired by Nico's, so if your power supply is less than +-24V then go for Nico's SSA. 🙂
Permission?
Come on man just go for it!
We're waiting! 🙂
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