Me really realy stupid
never tough of that. One end up twidling things and actualy not listening to any records any more
Plus wife girlfriend of what have you (may even be flipping cat) are going to be totally pissed off and general screamed comment wuld be (as I remember)
WHY DO YOU PLAY THAT RECORD OVER AND OVER AGAIN YOU KNOW THAT I DO NOT LIKE IT AND YOU DOING IT ON PURPOSE TO DRIVE ME INSANE.
Cat may Just decide to take it out on speakers...
Now seriously altering one branch of the current source will efect the response of the branch as the transistors are designed to keep things in ballance
So for more gain Twidle???????
never tough of that. One end up twidling things and actualy not listening to any records any more
Plus wife girlfriend of what have you (may even be flipping cat) are going to be totally pissed off and general screamed comment wuld be (as I remember)
WHY DO YOU PLAY THAT RECORD OVER AND OVER AGAIN YOU KNOW THAT I DO NOT LIKE IT AND YOU DOING IT ON PURPOSE TO DRIVE ME INSANE.
Cat may Just decide to take it out on speakers...
Now seriously altering one branch of the current source will efect the response of the branch as the transistors are designed to keep things in ballance
So for more gain Twidle???????
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that might be one explanation, or a big mismatch between the two SK170's is at the root of this. you could try a little circuit to test the JFETs, put the gate to GND, the drain to a positive voltage e.g. 5V, the source with 1MOhm to -5V. then measure the G-S voltage and use that for matching. sorry i don't have a drawing at hand...
very nice. i would put a XLR at the input instead, and build adapter cables with crocodile clips
I was planning to build that one, but now I am thinking to get/design a balanced one (I even did draw something up in spice).
OK from The Art of Electronics also known as the Bible
Quote >
2.50).
Figure 2.51 shows two variations on
the multiple-mirror idea. These circuits
mirror twice (or half) the control current.
In the design of integrated circuits, current
mirrors with any desired current ratio
can be made by adjusting the size of the
emitter junctions appropriately.
Texas Instruments offers complete monolithic
Wilson current mirrors in convenient
TO-92 transistor packages. Their
TL 01 1 series includes 1: 1, 1 : 2, 1 :4, and
2: 1 ratios, with output compliance from
1.2 to 40 volts.
But this is just a taste of what a nuttter I am now I am going to crawl in a dark corner and stay there for a while
Quote >
2.50).
Figure 2.51 shows two variations on
the multiple-mirror idea. These circuits
mirror twice (or half) the control current.
In the design of integrated circuits, current
mirrors with any desired current ratio
can be made by adjusting the size of the
emitter junctions appropriately.
Texas Instruments offers complete monolithic
Wilson current mirrors in convenient
TO-92 transistor packages. Their
TL 01 1 series includes 1: 1, 1 : 2, 1 :4, and
2: 1 ratios, with output compliance from
1.2 to 40 volts.
But this is just a taste of what a nuttter I am now I am going to crawl in a dark corner and stay there for a while
I have done that in the R1 build trying to fight big output offset I got with that build.
Lowering R3 ad R7 does increase the mirrors output current but it is very difficult to do both at the same value in order to avoid causing output offset.
IMO modifying the mirrors output current also alters the mirrors output impedance and that will cause a shift in the riaa filter response.
Ok, getting to the root of my issue was simpler than I thought. None functioning 2sk170 on one side of one channel, all of the other components around it measured fine- and it still played. So obviously this device was at fault. I fired up the soldering iron to remove it, flipped the pcb over to apply the iron and hey presto- a massive dollop of solder shorting out the S_G pins on the transistor. a quick swipe of the iron to remove the offending blob and everything is good. All voltages are equal across both sides and both cards and everything sounds good.
Time to box them up. Thanks for all the help along the way guys. I shall be throwing 1000 transistors into the swaps thread, anyone can have them, they are mostly 337 @450hfe and above and 327 @390hfe and below. There will be some in the 2x untested bags of useful values ie around 400
Time to box them up. Thanks for all the help along the way guys. I shall be throwing 1000 transistors into the swaps thread, anyone can have them, they are mostly 337 @450hfe and above and 327 @390hfe and below. There will be some in the 2x untested bags of useful values ie around 400
The protection diodes must be protected (I thought) also I want to use this thing to measure floating items in power amplifiers running of +/- 70V. For this purpose I may even need higher values for these resistors. They, and the two 500ohm values will be switchable. Any other thoughts on this? Currently it is just a simulator-prototype.