Hi!
I guess relying on VAS trannies for sonic quality was not the main consideration VAS are for current and voltage handling (stability), I believe the differential input pair plays the major role on sonic quality reproduction. IMO
TY!
Not the input pair itself only, the working conditions environment they're in is important. Constant input bias current is essential here, otherwise in/out subtraction is not correct and it has unavoidable integrated error.
Exactly, I am thrilled to see more projects to arise in this thread, since creativity with individual approach is what I like here. Everywhere, to be more specific.
It's perfectly OK. VAS or TIS (as some like to name the second stage) bias will go up with temp to some 15 mA at 50°C, but that's even better if amp si pushed hard and the second stage is even more rigid.
To be more specific this 2,3 mA of input bias current is divided among Ic and feedback resistor. Actually there's 1,6 mA of input collector current through input pair.
Wrong completely, please turn on logic. Also Shaan will not be pleased with OT pollution.
Wrong completely, please turn on logic. Also Shaan will not be pleased with OT pollution.
Wrong completely? You mean CCS will improve distortion, but not PSSR?
Could you support anything what you said with any measurements or at least some simulations(its easy to learn), because your logic is not based on technical facts.
Where did I say that only distortions will improve??? Normally both PSRR and distortions will be improved. Firmly proved that already with measuring results in the VSSA thread. Real scope pics posted to prove the difference between CCSed and non CCSed VSSA, of course in a favour to CCSed version.
Where did I say that only distortions will improve??? Normally both PSRR and distortions will be improved. Firmly proved that already with measuring results in the VSSA thread. Real scope pics posted to prove the difference between CCSed and non CCSed VSSA, of course in a favour to CCSed version.
You said, completely wrong and I understood that I am wrong in both of my assumptions.
P.S. If you can see any distortion on the scope screen then you are in trouble.
mmm... The thread is in trouble.
Hi dadod.
Please use the VSSA thread for discussion and teaching, like CCS etc. , everybody loves to see, read and learn. Your presence in this thread is much appreciated, as long as you stick to the topic of building yourself or help build fellow diy-ers a PeeCeeBee and it's derivatives with, maybe, a 'dadod version' of peeceebee without CCS, which will be great news for all of us.
Happy listening to all.
shaan
Hi dadod.
Please use the VSSA thread for discussion and teaching, like CCS etc. , everybody loves to see, read and learn. Your presence in this thread is much appreciated, as long as you stick to the topic of building yourself or help build fellow diy-ers a PeeCeeBee and it's derivatives with, maybe, a 'dadod version' of peeceebee without CCS, which will be great news for all of us.
Happy listening to all.
shaan
What I was trying to say that constant current to the input trans(if you still do this amp without ccs) will inprove PSSR but not distortion. Low PSSR could be bypassed with good power supply. I don't suggest any change to this amp just some opservations.
br dado
hullo chaps - since this is the practical part of this amplifier's development thought i can ask here- I wonder if anyone has made some measurements of the amplifier build and share their results ? I mean real world measurements and not just the sims (not that the sims are not valuable) - things like thd vs power, fft, clipping behaviour etc... i realise not everyone has the ability to do these but would be interesting if a few have.... very interesting design and thread btw...