First unzip and than use one of several online gerber viewers:
Online Gerber Viewer
CircuitPeople™ Home - Free Online Gerber File Viewer
webGerber
etc.
Quasar is now at version 17 and can be listen in Bucharest show-room. It was compared with many high-end amplifiers from Accuphase, Electrocompaniet, Unison Research, Sugden, Naim, Hypex, Vincent, Densen, Myryad, Music Hall etc. and a dozen of DIY amplifiers.
Anyone who pass trough Bucharest and want a listening session, is welcome. I promise will not be disappointed at all.
Regards,
Tibi
The most interesting approaches concerning amplifier circuit topologies I know, which work not in pure Class-A was the QUAD models 405 and 303 and the Yamaha HCA-Amp MX-10000 - go to
http://www.diyaudio.com/forums/soli...lic-conversion-amplification-hca-circuit.html
Although also that Yamaha topology is easy and good to understand, this approach was not otherwise apply due to low popularity.
This fact is a great pity.
http://www.diyaudio.com/forums/soli...lic-conversion-amplification-hca-circuit.html
Although also that Yamaha topology is easy and good to understand, this approach was not otherwise apply due to low popularity.
This fact is a great pity.
Mosfet quad 405 - changes
Hello Everyone,
I am also working on this project based on the attached schematic. It is derived from the previous versions of the mosfet quad 405/quasar.
I am using 3 pairs of ALF16N16W and ALF16P16W as output devices.
Other important modifications:
R6 - 2.2K for OpAmp increased gain.
C7 (OpAmp output filter) decreased to 330pF for increased positive slew-rate
R24 - 10ohms - sets the driver bias current to ~55mA
Bridge components:
L 2.8u, C 120pF
R11 - 100R (the one that goes to the output and provides the drive signal)
R18||R19 - a total of 250R (the resistor that provides the negative feedback)
R17 - 100R - for increasing Vas gain.
Gate resistors increased to 1k on both sides
Miller cap for Q7 (collector-base) or 680pF.
The reason for bridge alteration was that the initial 47ohm resistor does not provide enough drive voltage for the output devices. Negative side was limited to approximately 1A/device.
And the purpose for the latter, as you might have guessed, suppressing parasitic oscillations.
Tried also other configurations, but this is the simplest and works well.
No point in further increasing the gate resistors or Miller cap, stability remains the same, only SR decreases.
Amp is now stable only mild oscilation (0.5-1V ~30-50MHz) occurs during hard clipping on low impedance (<=2ohms) and supply voltage higher than +-40V.
My goal is amplifier stability into low impedance loads like 1ohm, without going berserk in oscillations of all flavours.
Till now I've managed to achieve this stability with voltages lower than -+60V with no load.
Approx SR: +25V/us and -15V/us measured with 2ohm load and +-30V supply.
Please share your thoughts on this matter. Do you think that these changes would harm the principle of operation in any way? For me it was the only solution for obtaining the desired results (stability into low impedance loads).
This amplifier is still under test and subject to change, as i feel that there is room for improvement.
Do let me know if any additional information (e.g. scope screens, component values) is required from my side, and i would gladly share.
If you feel that my posting here is inappropriate due to thread hijacking reasons, please let me know and i will open a new discussion.
Thank you,
Serban
Hello Everyone,
I am also working on this project based on the attached schematic. It is derived from the previous versions of the mosfet quad 405/quasar.
I am using 3 pairs of ALF16N16W and ALF16P16W as output devices.
Other important modifications:
R6 - 2.2K for OpAmp increased gain.
C7 (OpAmp output filter) decreased to 330pF for increased positive slew-rate
R24 - 10ohms - sets the driver bias current to ~55mA
Bridge components:
L 2.8u, C 120pF
R11 - 100R (the one that goes to the output and provides the drive signal)
R18||R19 - a total of 250R (the resistor that provides the negative feedback)
R17 - 100R - for increasing Vas gain.
Gate resistors increased to 1k on both sides
Miller cap for Q7 (collector-base) or 680pF.
The reason for bridge alteration was that the initial 47ohm resistor does not provide enough drive voltage for the output devices. Negative side was limited to approximately 1A/device.
And the purpose for the latter, as you might have guessed, suppressing parasitic oscillations.
Tried also other configurations, but this is the simplest and works well.
No point in further increasing the gate resistors or Miller cap, stability remains the same, only SR decreases.
Amp is now stable only mild oscilation (0.5-1V ~30-50MHz) occurs during hard clipping on low impedance (<=2ohms) and supply voltage higher than +-40V.
My goal is amplifier stability into low impedance loads like 1ohm, without going berserk in oscillations of all flavours.
Till now I've managed to achieve this stability with voltages lower than -+60V with no load.
Approx SR: +25V/us and -15V/us measured with 2ohm load and +-30V supply.
Please share your thoughts on this matter. Do you think that these changes would harm the principle of operation in any way? For me it was the only solution for obtaining the desired results (stability into low impedance loads).
This amplifier is still under test and subject to change, as i feel that there is room for improvement.
Do let me know if any additional information (e.g. scope screens, component values) is required from my side, and i would gladly share.
If you feel that my posting here is inappropriate due to thread hijacking reasons, please let me know and i will open a new discussion.
Thank you,
Serban
These are the results I got with a modified 405
http://www.diyaudio.com/forums/soli...ower-quad-405-experiment-390w-into-1-ohm.html
I have tested down to 0.25R and have found no instability, what is the advantage of the FET output stage
Stuart
http://www.diyaudio.com/forums/soli...ower-quad-405-experiment-390w-into-1-ohm.html
I have tested down to 0.25R and have found no instability, what is the advantage of the FET output stage
Stuart
Good day! Gathered 11b ver. Quasar unilateral PP so to say layout. all small transistors part no mpsa42 and 92 on one pair of output transistors with a supply of +-40V. Very happy with the sound reminiscent of the Quad 405 is only the bass more distinct and expressive! Tiberiu thanks to Vicol for a great amp. Here is the layout.