Studio Reference Amplifier

[irwanks]

my work, sr200 with 1 pair transistors was supplied by 40vac 5 ampere transformer. Sound had nice bass and mid.

 

[amptech]

A quick tidy up with some cable ties....

 

[irwanks]

Sir apex, What is the rating watt for 10 ohm resistor between signal ground and ground (1/4 or 1/2 or 1 or 2 watt) ? What is the rating watt for 220 ohm resistor between emitor 2sc4793 and emitor 2sa1837 (1/4 or 1/2 or 1 or 2 watt) ? What is the rating for coil (1uH or 2uH or 10uH, or etc) ? Thank you very much.

 

[irwanks]

A quick tidy up with some cable ties....

Thank you for your ideas

 

[apexaudio]

Sir apex, What is the rating watt for 10 ohm resistor between signal ground and ground (1/4 or 1/2 or 1 or 2 watt) ? What is the rating watt for 220 ohm resistor between emitor 2sc4793 and emitor 2sa1837 (1/4 or 1/2 or 1 or 2 watt) ? What is the rating for coil (1uH or 2uH or 10uH, or etc) ? Thank you very much.

U can use 1W resistors and 4uH coil (post #43)
Regards

 

[irwanks]

U can use 1W resistors and 4uH coil (post #43)
Regards

Thank you sir, i will change it. I use one 2k 1 watt resistor before zf15v for 40vac transformer. Is it allright?

 

[apexaudio]

Thank you sir, i will change it. I use one 2k 1 watt resistor before zf15v for 40vac transformer. Is it allright?

Use 2k2/2W

 

[leonatax]

Sir Apex I have measured volts on 100r resistor and I have 850mv and 2mv on out, is it ok that I use TL071 instead Lf411 and what about TL081

 

[leonatax]

Sir Apex what do you think about this security system it is for 6 chanel but only for 32+- volts what can I do to use it for 40+-vdc psu

 

[apexaudio]

Sir Apex I have measured volts on 100r resistor and I have 850mv and 2mv on out, is it ok that I use TL071 instead Lf411 and what about TL081

That's OK

 

[apexaudio]

Sir Apex what do you think about this security system it is for 6 chanel but only for 32+- volts what can I do to use it for 40+-vdc psu

Connect 15V zener in series with relays

 

[leonatax]

Thanks

 

[viki_v2]

Hello Mile,
I will be making SR200 v2.2 With Sanken 2sc2922-2SA1216.
What should ve voltage and Current Requirement for 1 pair and 2 pairs.
As well What will be the output with Single pair and 2 Pairs.

 

[carlmart]

Apexaudio,

Some time ago I asked about the possibility of using a dual fet at the input, probably improving offset quite a bit and following paths high quality amps have followed.

Any news on that or hint on how to do it?

 

[JOHN BALI]

Driver TR?

Hi Apex,
I will try to make new PCB design for SR200, it hard I guess
I want to ask it is ok if I separate driver A1837/C4793 from main heatsink?
so the PCB is not so big
I saw your SR400 component side, there is only VBE multiplier (BD139) on main heatsink...
Also can replace A1837/C4793(out of stock here) with A968/C2238(I have some)?

Regards

 

[apexaudio]

Hi Apex,
I will try to make new PCB design for SR200, it hard I guess
I want to ask it is ok if I separate driver A1837/C4793 from main heatsink?
so the PCB is not so big
I saw your SR400 component side, there is only VBE multiplier (BD139) on main heatsink...
Also can replace A1837/C4793(out of stock here) with A968/C2238(I have some)?

Regards

You can use A968/C2238 on separate heatsink, output stage of SR400 is TEF, MJE340/350 are predrivers on separate heasinks, and one pair A1493/C5200 is drivers on main heatsink with outputs.
Regards

 

[apexaudio]

Apexaudio,

Some time ago I asked about the possibility of using a dual fet at the input, probably improving offset quite a bit and following paths high quality amps have followed.

Any news on that or hint on how to do it?

I work on new amplifiers using dual fet at the input, one will be in thread '100W Ultimate Fidelity Amp' and second will be here.
Regards

 

[carlmart]

Thanks, Apexaudio. Looking forward to it.

Also curious on what might be different between those two, as the inputs are very much the same on both.

 

[apexaudio]

Thanks, Apexaudio. Looking forward to it.

Also curious on what might be different between those two, as the inputs are very much the same on both.

VAS is different like in AX and SR amps.

 

[leonatax]

Sir APEX can I use BC557c(b) BC547c(b) instead of BC560c BC550c, or BC550b-560b