Yes. And can be used to current limit a soft start.
Remains the second target: Regulate the V right at the Amp power transistor current source pin. (for transients consumption). My suggestion:
http://www.esperado.fr/images/temp/reg.jpg
The regulation parts can be on an other board. What seems a good idea to me is to have the power regulation device right on the Amp circuit. It will reduce to none the influence of the power wiring. and i'm sure we can reduce any caps at the regulated point to <= 1µf, so, use film ones for no Hf limitation..
This power regulation transistor could be used too for instant protection in a very elegant way, adding no parasitic impedance in serial with power supply or loudspeakers. Just putting them in the nonconductive state.
Very good, all details prepared to bring new TSSA amp into life.
I asume that all necessary transistors are matched, so we can start with CCS-s only, to set correct constant current levels needed. There are three of them on one PCB, so this will be opening part of construction.
Regards Andrej
Very good, all details prepared to bring new TSSA amp into life.
I asume that all necessary transistors are matched, so we can start with CCS-s only, to set correct constant current levels needed. There are three of them on one PCB, so this will be opening part of construction.
Regards Andrej
I just have to mesure BC560 and BC550, all others are yet done.
Marc
Many years ago, lets say around 20, I did the last PCB by etching. The same chemistry was used and I still remember the smell and bubbles from the process, and worries that the reaction would be to fast, to hot etc. But the moment of glory was there when PCB tracks appeared from the foggy bursting fluid reaction. Always happy moment when finished, brought a big smile to my face.
Many years ago, lets say around 20, I did the last PCB by etching. The same chemistry was used and I still remember the smell and bubbles from the process, and worries that the reaction would be to fast, to hot etc. But the moment of glory was there when PCB tracks appeared from the foggy bursting fluid reaction. Always happy moment when finished, brought a big smile to my face.
I like this moment to...the pcb born after spending lot of time on computer to route project. The procedure is quite easys. I do it in front of garage door so no soucy with bad vapour...
Marc
Idefixes,
What is your procedure for etching. Sometimes mine turns out great, others not so. I have never done two stage method.
What is your procedure for etching. Sometimes mine turns out great, others not so. I have never done two stage method.
So
- printing with laser printer on transparent paper named "papier calque" in french
- expose under UV fluo bulb about 150s on Bungard positf PCB
- revalating in mix of 20ml NaOh + 1L distilated water
- wash in fresh water
- etch in mix of 200ml distilated water + 100ml HCL + 100ml H2O2 (Give big warning to mix in the order i gave you above it can be dangerous if not). The time wil depend to Cu to dissolve on pcb. You must controle process.
- wash in fresh water.
Marc
I do not think Bursons sell them any more!?
By the way, i have made one before and it works very well besides of the offset in the PMBFJ620 which i did not see come....
http://www.diyaudio.com/forums/anal...scode-diamond-buffer-opamp-3.html#post2658193
With a little luck i can make a 2 stage CFB in the same space.
WOW I didn't know what you did already. Amazing.
I would be the first to order few of these CFB OP amps.
Some quick calculations tell me that it will not be as compact as the "discrete opamp" i already have made.
I need to use SOT-223 package for the output devices.
I need to use SOT-223 package for the output devices.
It suffers the same problem as TSSA V1.6 -> high zout of ~60Ohm.
but 2Vpp input, 6dB gain and Load of 1K will give you 3,67Vpp out with THD of 0.000323% thd..
I do not think it is bad. See attachment...
but 2Vpp input, 6dB gain and Load of 1K will give you 3,67Vpp out with THD of 0.000323% thd..
I do not think it is bad. See attachment...
So, it looks OK for a 10K load, witch respond at most frequent requirement in a preamp ?
And, as output stage in a preamp has to be an overkiller low Z headphone amp, for it can drive any capacitive load, easy to add a single buffer with discreet transistors, don't you think ?
What about the PSRR ? (I love the Nightly maintenance pictures 🙂
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I think the PSRR is okay.
Distortion into 10K is a little higher but better roll off.