It just simulate the trimmer there. You have 390ohm resistor+trimmer series, to set the bias for the 1st stage.
Sajti
Also, it limits the range ... if you had the trimmer set to a real low value,
you might damage your input stage or even the VAS.
390R + a 200R trimmer gives .9ma - 1.5ma LTP current.
With different VAS components - input or second stage devices ... it is
a really helpful to be able to trim the operating currents without changing
passives (fixed resistors).
Also , for "tweakers" .... being able to change current might optimize
the performance.
OS
I'm going to try this. If you say this has a negative co-efficient ... pair
it with 2Q ccs's.
(that's how I will approach it.)
OS
I must explain this.
With a slide switch, select the 1st or second amplifier ,a pair of relay contacts transduces the loudspeaker from 1st to 2nd amplifier and vice versa.
An analog voltmeter(fast enough ) ensures same outputs levels.
A pair of ears or some pairs, listening some known music again and again ....
That's all.
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Thimios,
I was just giving you are hard time. There are many who will discount any listening test that runs through a switch or even the relays, they always have a reason to discount the simplest listening test no matter how obvious a preference may be. I am looking forward to your test and how you think the two different input sections sound.
I was just giving you are hard time. There are many who will discount any listening test that runs through a switch or even the relays, they always have a reason to discount the simplest listening test no matter how obvious a preference may be. I am looking forward to your test and how you think the two different input sections sound.
Thermal gain (which is a tiny portion of actual gain) of a BJT is directly proportional to Vce. The standard diamond has high Vce at the outputs whereas in my circuit the first 4 transistors control the output, and they see no more than 1.2V Vce. so I'd say if anything my circuit will have less thermal error than an ordinary Diamond.
I love the looks of that circuit. Will it handle high voltage rails? Can't wait to get my Slewmonster boards so I can start trying some of these circuits.
I'm just curious. Hoping for around +-75V rails. If not +-50V rails. Want to plug it into a Slewmonster board and see how it works. I have a good supply of KSA99/KSC18455 devices but I don't know if they will work for this circuit. Trying to learn and building different circuits is all part of that.
Blessings, Terry
Blessings, Terry
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My curiosity is in-between. I'd like to see a few more parts, such as enough for about 8W to 8R and some kind of baker clamp or other clipping mitigation. This might be a fun flea power project for desktop use (at point blank range).Terry,
It doesn't have enough parts! Perhaps OS can add a bunch more.
Terry,
It doesn't have enough parts! Perhaps OS can add a bunch more.
Lol,it already has as many parts as the peeceebee and it is lacking the VAS and outputs.
If I could see the rest of the component values, I might attempt to breadboard it.
I love the looks of that circuit. Will it handle high voltage rails? Can't wait to get my Slewmonster boards so I can start trying some of these circuits.
All the CFA's (and most of my VFA's) , run on the same +/- 12V
that the servo does. The VFA's are cascoded to full rail and the CFA's
use level shifters.
The advantage to this - is being "rail independant" . Thimios had to
change the zener regulator dropping resistor for low rail voltage .. that's
it. Any rail will do ..from 35V (actually <20) to 85+. The CCS's,IP pair, and
all else that matters to keep a stable VAS current are regulated at 12V.
OS