Hi Al,
It looks like a good design. I have a natual aversion to seeing traaces snaking around between component leadss like transistors. Leakage you know. I do think your surround amp will be the best sounding around.
You can never tell until a prototype is built.
-Chris
It looks like a good design. I have a natual aversion to seeing traaces snaking around between component leadss like transistors. Leakage you know. I do think your surround amp will be the best sounding around.
You can never tell until a prototype is built.
-Chris
🙂 Hi,
I think I`m going to try and make one of these 🙂
Looking at the 2N5401 in the Mouser catalog I see there are different names them... 2N5401TFR, 2N5401TA,,,, CTA,,,, TAR and so on and so on..... Does it make a difference?
Thanks!
Regards,
Peter
I think I`m going to try and make one of these 🙂
Looking at the 2N5401 in the Mouser catalog I see there are different names them... 2N5401TFR, 2N5401TA,,,, CTA,,,, TAR and so on and so on..... Does it make a difference?
Thanks!
Regards,
Peter
Hi Peter,
If you give me couple days I'll get you the bill of materials of the parts that I used on the prototype. I ordered mostly all the parts from Digi-Key, but there were a few from Mouser.
Al
If you give me couple days I'll get you the bill of materials of the parts that I used on the prototype. I ordered mostly all the parts from Digi-Key, but there were a few from Mouser.
Al
I want to decrease the gain of my symasym at 10. (my DAC have 6Vp-p output). The problem is that I'm not sure if it is wise to make source degeneration for 2sk170bl input pair.
In sym, if i use 33ohm source resistors and 2k2 instead of 499 feedback resistor the gain will be 10. The THD will decrease a little bit but I'm not shure if the amp will be sonicaly the same ...
What do you think about that?
In sym, if i use 33ohm source resistors and 2k2 instead of 499 feedback resistor the gain will be 10. The THD will decrease a little bit but I'm not shure if the amp will be sonicaly the same ...
What do you think about that?
Roender, symasym might degrade sonically if you have that large input signal. The problem is the large swing of the inputdiffamp. You also have to lower supplyvoltage to ~32v, otherwise you exceed max Vds of 40v for the sk170. Also, you will need even more than 33ohm degeneration to keep feedback levels at the old value.
In theory you should have a floating cascode to compensate for this inputsignal. Why is your DAC delivering that large signal ?
Mike
In theory you should have a floating cascode to compensate for this inputsignal. Why is your DAC delivering that large signal ?
Mike
This is the schematics.
In fact, at 1W-8ohm, THD-20 decrease from 0.0029% to 0.0022%.
Phaseshift at 20Khz, 2.9grd
Mike, this is my DAC
http://www.audiokit.ro/ro_dac_rd2.html
http://www.audiokit.ro/img/photo/dac.jpg
and this is IV convertor with 6Vp-p output
http://www.audiokit.ro/img/schematics/iv_conv.gif
In fact, at 1W-8ohm, THD-20 decrease from 0.0029% to 0.0022%.
Phaseshift at 20Khz, 2.9grd
Mike, this is my DAC
http://www.audiokit.ro/ro_dac_rd2.html
http://www.audiokit.ro/img/photo/dac.jpg
and this is IV convertor with 6Vp-p output
http://www.audiokit.ro/img/schematics/iv_conv.gif
Attachments
Roender, with R23 increased to 2.2k, you really should reduce C17 to 47...100µF. You also might consider degeneration to Q8/9.
Where has the wilson current mirror gone ?
You should take the Vds-threat to the sk170 serious, with a 6v input signal, vds to the jfets will increase to ~42v, killing them. With a 10% margin, you end up at supply voltage of max 31v.
Mike
Where has the wilson current mirror gone ?
You should take the Vds-threat to the sk170 serious, with a 6v input signal, vds to the jfets will increase to ~42v, killing them. With a 10% margin, you end up at supply voltage of max 31v.
Mike
MikeB said:
This schematic is only for symulating. In sym, there is no difference with wilson CM, only in practice will improve thermal balance.
It happens... And you dont want that risk.
For better AC-balance at low freqs to the diffamp. Smaller c17 can improve bass... Bigger is not always better.
Mike
Thank you Mike. You are a gold mine 😀 and your support is much better than many commercial customer support departaments
Hi roender,
Try a cascode for your fets to lock the voltage a little lower. That's been my plan all along.
What do you think about that idea Mike?
-Chris
Try a cascode for your fets to lock the voltage a little lower. That's been my plan all along.
What do you think about that idea Mike?
-Chris
Hi Clem,
Fixing the collector (or drain) at a specific voltage can help linerarise the front end, plus shield it from excessive voltages.
That's a good bang for the buck!
By running the diff pair at a lower voltage you will reduce the instantaneous die temperature cycling (or memory) a little. 😀
-Chris
Fixing the collector (or drain) at a specific voltage can help linerarise the front end, plus shield it from excessive voltages.
That's a good bang for the buck!
By running the diff pair at a lower voltage you will reduce the instantaneous die temperature cycling (or memory) a little. 😀
-Chris
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