Hello. There was a bootstrap analysis when the FR100 was introduced. MR Mile added this circuit to increase the voltage by a couple of volts on VAS as I understand. I would ask if there would be any advantages to remove the bootstrap and using a stabilized power supply instead. I'm not an electronics expert just an enthusiast.... can I do this modification on the FR50?
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Hello sir ! I have all the admiration for your cables. Can you share the pcb for headphone amplifier PP12 in gerber or lay6 format? Thank you very much !🙂
Hello everyone in the group, first I want to thank SR. Mille (Apex) and all members who actively participate in helping with the projects. I'm wanting to assemble the SR100, but I'm having problems getting some components here, so if anyone can help me I'll be grateful:
I can use the tip41 and tip42 pair in the Drivers, as I couldn't find the mje15031 and mje15030, I can also replace the 2n5401 with mpsa92 ?
the bc550 by bc546 and the bc560 by bc556?
And can the 10uf and 1uf polyester capacitor be replaced with a non-polarized electrolytic because I don't think these are in any way accessible?
I only think all ceramic capacitors are 50 volts. I would be grateful if someone could answer me.
Thanks.
I can use the tip41 and tip42 pair in the Drivers, as I couldn't find the mje15031 and mje15030, I can also replace the 2n5401 with mpsa92 ?
the bc550 by bc546 and the bc560 by bc556?
And can the 10uf and 1uf polyester capacitor be replaced with a non-polarized electrolytic because I don't think these are in any way accessible?
I only think all ceramic capacitors are 50 volts. I would be grateful if someone could answer me.
Thanks.
BC550 and BC560 are low noise transistors. TIP's are far inferior in quality, but may work, although MJE's are available in Brazil, alike 2N5401. If you PM me, maybe I can help you someway.
Hello all Diy members Now final my sr200 done .I will shear my youtube video
Please check sound quality .it's recorded from Mobile camera Thanks mile and all my diy members.
Please check sound quality .it's recorded from Mobile camera Thanks mile and all my diy members.
Can the 0R33 5W resistor be replaced by the 0R22 5W in the SR100 or will there be problems or changes needed in the rest of the circuit?
Fabio, 3 paralleled 1-ohm carbon resistors will do the job in a much better way than regular wire resistors available in Brazil.
I greet you all. Please help and advice. I can't adjust the bias on the Apex SR50 amp. I changed resistor R30 from 1K to 1K5 and I still don't have about 2V voltage on BD139. Please advise me what to focus on and where the problem could possibly be. Thank you very much and have a happy and merry Christmas. I use layout Coolet.
Kindly link the layout and schematic post. There are so many designs and so many versions. I am not saying I will be able to help but experts need them at hand so it's convenient.
The amplifier plays, the sound is good, but the bias cannot be set. surely the sound will improve even more after the adjustment.
Vbe_multi (Q11, P1, R29 and R30) is most likely no working "properly".
You made change for R30 from 1K to 1K5 with no visibile BIAS changes
i.e. differences in Vbe_multi min-max adjusting voltages (voltage measured on C8 adjusting P1)
For DualEmitterFollower DEF OPS you need aprox. >4xVbe = >2,5V on C8
When you adjust P1 to the one off the two extrems (0R and 1K), for P1->0R, what is your voltage measurement on C8?
C8 voltage = Vbe_multi (V) = Vbe * (1 + R30/(R29+P1)) ; Vbe= aprox 0,65V
Check R29 value!
Maybe is not 220R but higher in value, so Vbe_multi voltage cant reach necessary max level (more then 2,5V on C8)
Measure voltage differences on VAS R28 100R and on VAS current mirror R26 R100 (you must read on DMM aprox. 0,85V...1V on 100R => 8,5...10mA)
Hello Dragan and everyone. Thank you very much for your support. I measured -16 VDC on capacitor C8.
The Christmas holidays are about to start, so I'll check it out later. When I get to it, I'll write what I measured. I wish you a merry Christmas.
The Christmas holidays are about to start, so I'll check it out later. When I get to it, I'll write what I measured. I wish you a merry Christmas.