It's stable now.This is not DC pulses,this is very low frequency output.
My phone is offender.This is not happened by amp.Use smaller input cap to remove this 😉
Today I worked on very simple amplifier.Tomorrow I'll upgrade it and maybe post new topic.It uses only two (maybe 4 for higher current) transistors on output and VAS is changed with transformer.
Hi Acca,
can I used your schema using ziklai output? Can you draw for this? No available here in our local store bdx33c/34c. Thanks in advance.
Regards,
Boyet
Use BD139/140 some 2N or TIP or another complementary transistors.Between B and E of power transistor put 100R resistor.Make classic darlington.
Use BD139/140 some 2N or TIP or another complementary transistors.Between B and E of power transistor put 100R resistor.Make classic darlington.
Thank you Acca.
I have problem with bias.It's 0V at start,but after few min's it's 50mV.
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Check this:
http://www.diyaudio.com/forums/solid-state/242641-vstt.html 🙂
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Check this:
http://www.diyaudio.com/forums/solid-state/242641-vstt.html 🙂
Little up-date : BG1-BJT (MJL4281/4302) is up to day in my audio systeme. Last week i swap from CD to computer with Jriver software as player and music tracks on FLAC form. Computer is configurated in Bit perfect mode (wasapi under W7). What i can say is that the back return to CD source is quite impossible as the rendering is pleasent. All previous qualtities i have reported with BG1 introduction are magnified by source modifcation...really, really good music moments...
Marc
Marc
Hi,
I am using motherboard optical spidf output to feed my old TDA1541 DAC but i am waiting a ESS9023 new one.
Marc
I am using motherboard optical spidf output to feed my old TDA1541 DAC but i am waiting a ESS9023 new one.
Marc
As far as I can see Acca's BDAmp 50x50 pcb is designed for ECB pinout input transistors (like 2SA970) and on the schematic transistors used are EBC pinout (2Nxxxx).
Maybe my mistake.But you can use transistors with ECB pinout.
Hi Acca,
Its playing now your circuit using sziklai output with 2sa970/2sc2240 input.
Bias only 1 diode 1N4148 and some modification of the value of parts. And the result? Sounds great.🙂 Dead silent if no signal compare to my lafet version.
Regards,
Boyet
Maybe my mistake.But you can use transistors with ECB pinout.
Hi Acca,
Its playing now your circuit using sziklai output with 2sa970/2sc2240 input.
Bias only 1 diode 1N4148 and some modification of the value of parts. And the result? Sounds great.🙂 Dead silent if no signal compare to my lafet version.
Regards,
Boyet
Maybe my mistake.But you can use transistors with ECB pinout.
Yes, I already have them 2sa970/2sc2240.
As I say,sound is perfect.😉Hi Acca,
Its playing now your circuit using sziklai output with 2sa970/2sc2240 input.
Bias only 1 diode 1N4148 and some modification of the value of parts. And the result? Sounds great.🙂 Dead silent if no signal compare to my lafet version.
Regards,
Boyet
Little progress in versatil 50 building process : speaker delay and dc protection board. This must be feed by 0/+12Vdc PSU.
I re-etch new versatil 50 board as i gave an evolution to the board by reduce the whole size. I am waitjing some SMD resistors to populate them.
I re-etch new versatil 50 board as i gave an evolution to the board by reduce the whole size. I am waitjing some SMD resistors to populate them.
Attachments
Little progress in versatil 50 building process : speaker delay and dc protection board. This must be feed by 0/+12Vdc PSU.
I re-etch new versatil 50 board as i gave an evolution to the board by reduce the whole size. I am waitjing some SMD resistors to populate them.
Nice work. But there is very simple way to add very small psu circuit. Only few resistors, one npn tranistor with zener diode and there is no need separate transformer for protection board. Speaker protect can be supplied directly from amp psu voltage.
Nice work. But there is very simple way to add very small psu circuit. Only few resistors, one npn tranistor with zener diode and there is no need separate transformer for protection board. Speaker protect can be supplied directly from amp psu voltage.
Hi Borys,
The 12V PSU exist all ready in soft start board so no issue with that.
Marc
Hi folks, I have been following this thread for a while and have decided to build my own. I have created the attached schematic based on Borys earlier schematic except with partys that I have. Can you have a quick glance over it for any mistakes before I create the board etc?
Thanks
Much appreciated.
Dom
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Thanks
Much appreciated.
Dom

Hi folks, I have been following this thread for a while and have decided to build my own. I have created the attached schematic based on Borys earlier schematic except with partys that I have. Can you have a quick glance over it for any mistakes before I create the board etc?
Thanks
Much appreciated.
Dom
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If I am not mistaken , at first sight , you have a positive feedback amp

Fab
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