and indeed in Spice the damping factor for 8 Ohm speakers is around 750 for this circuit.
Hui, Hui, I am afraid I must fasten the screws on my loudspeaker terminal better to make use of this damping factor .......
😀
Hui, Hui, I am afraid I must fasten the screws on my loudspeaker terminal better to make use of this damping factor .......
😀
Thanks. I likely will try both.
Is the highest voltage p-ch puck you have found the IXTN32P60P at 600V? (Unrelated spec for this project, I know)
I'm planning to set up the bias circuit so that the cold and hot temperature gives a 1V volt drop (0.5V drop per device) between cold and hot
eg 10V when cold and 9V when hot.
That might change a bit when I personally measure the devices on my heat sink though.
O.k. 2picodumbs!
🙂
What can I tell new....I managed to get darker or brighter/lively sweeter sound by choosing different feedback values.
I decided to go for 30dBAs starting point half closed loop gain 🙂 gain with a 1k5 load and two CFB resistors of 15k and a gain resistor of 220R. Then with a 1k5 overall feedback resistor to the 20dB of closed loop gain and a sound between dark an bright with a fair amount of sweetness.
Still not finally decided how to bring the OLG down by the load resistor, cascode feedback resistor and the current feedback resistor.
If the original XA25 really uses TO-220 laterals as second stage there must be a hidden fund at Nelson's laboratories from Renasas or Hitachi.......:--))
Or he uses really the Alfs. When in F7 one pair of J-FETs can drive the Alfs, why not in the XA25?
Another question is if the combination of j-Fets and laterals with less transconductance, can do combined, similar gain to get the low distortion figures.
I will do some Spice....🙂)
🙂
What can I tell new....I managed to get darker or brighter/lively sweeter sound by choosing different feedback values.
I decided to go for 30dBAs starting point half closed loop gain 🙂 gain with a 1k5 load and two CFB resistors of 15k and a gain resistor of 220R. Then with a 1k5 overall feedback resistor to the 20dB of closed loop gain and a sound between dark an bright with a fair amount of sweetness.
Still not finally decided how to bring the OLG down by the load resistor, cascode feedback resistor and the current feedback resistor.
If the original XA25 really uses TO-220 laterals as second stage there must be a hidden fund at Nelson's laboratories from Renasas or Hitachi.......:--))
Or he uses really the Alfs. When in F7 one pair of J-FETs can drive the Alfs, why not in the XA25?
Another question is if the combination of j-Fets and laterals with less transconductance, can do combined, similar gain to get the low distortion figures.
I will do some Spice....🙂)
Where did you get the idea that he is using Laterals in second stage? I was only suggesting to do that earlier to be different.
I was under the impression that this statement "The simple front end circuit uses uses two pairs of NOS complementary Fets" probably meant 2sk2013/2sj313 in the second gain stage (since he already has a stack of them in his parts bin)
Either way the goal is not to clone just to build using what you have on hand. I have both devices so I'll probably build both versions. The laterals in the second stage will produce a strong out of phase second harmonic (at least Exicon Parts will) without even playing with cascode feedback.
Last edited:
From memory TO247 packaged Laterals have a little more transconductance than 2sk2013/2sj313 not less.
Quoting Papa: http://www.diyaudio.com/forums/pass...snt-choose-lateral-mosfets-2.html#post3959821
"So that you don't have to speculate needlessly, I have a nice selection of laterals, dating back to early Hitachi parts. Most recently I have acquired a stock of Alfet parts: ALF08N16V ALF08P16V"
Yes but these aren't NOS
If he is using Laterals in the second stage, then either I really am a telepathic alien hybrid or that bastard has jumped in his time machine once again and stolen my ideas. Hahahaha 😀
Last edited:
Might I remind you bastards of post 6
Besides that look at data sheet of 2sk2013 at 50mA it also has zero temperature coefficient.
Last edited:
http://www.diyaudio.com/forums/pass-labs/299383-pass-xa25-10.html#post4901041
look here at the date and you see that lhquam was faster....🙂)
look here at the date and you see that lhquam was faster....🙂)
But I rarely read anything Ihqualm writes. hahahaha 😀
Anyway zero temperature coefficient is not a reason to use the laterals. They don't really hit zero tempco to around 200mA to 500mA, the Toshibas hit zero tempco at 50mA.
hahaha... funny!
what does that mean hit zero tempo. A balance where the temperature no longer gets higher?
what does that mean hit zero tempo. A balance where the temperature no longer gets higher?
Once you hit zero tempco, Id is not affected by changes in temperature.
Once you pass the zero tempco position it starts going the other way ie Id becomes smaller with increasing temperature.
And you already know what happens below the zero tempco position.
Once you pass the zero tempco position it starts going the other way ie Id becomes smaller with increasing temperature.
And you already know what happens below the zero tempco position.
Last edited: