Mighty Man.. I following you again.
Today I checked my friend's 2SK82 KE-33 and confirmed that it's possible again with IRFP9240.0.6 ohms Source resistor for both channels, up to 1.65A, Vds 16V, 29V supply.
But I want to hear that THF51 in DEFiSIT someday, in higher voltage and current! I also sent some THF51s and others to a gentleman in Germany for his fun..
Hi Chul, I'm wondering how many watt you could squeeze out from 2SK82 from this configuration.
Mighty Man.. I following you again.
Today I checked my friend's 2SK82 KE-33 and confirmed that it's possible again with IRFP9240.
But I want to hear that THF51 in DEFiSIT someday, in higher voltage and current! I also sent some THF51s and others to a gentleman in Germany for his fun..
Yes, indeed this is one of the diyAudio events you do not believe until it happens!
Chul sent me out of his list you saw here in the thread 6 of his best fitting devices for a combination with IRFP9240.
Isn´t this unbelievable?
So we have here at the moment, besides all the others, a strong axis Korea - Serbia- Germany.......diyAudio spirit.
Chul, wherefrom do you get these unbelievable "donkeys" that know in every circuit what to do?
Hi Chul, I'm wondering how many watt you could squeeze out from 2SK82 from this configuration.
Hi plasnu,
I have no idea about the output power of this. Maybe someone else can calculate? My speakers are just sensitive enough to enjoy. But Firstwatt amps are... generally for higher sensitive speakers.
What I can do for a measure is checking DC voltage and using ohm's raw.
So It is not possible for me to 'work with' gernerd or bad ZM.
@ Gerd,
Of course, these donkeys are from Singapore. My friend's 2SK82s are from the Sony Vfet kit with 2SJ28s+2SK82s selected by Nelson. I can see that selected ones are... selected and gives closer voltages.
Assuming that Sony SITs are not so variant as the Tokins, do you think it is possible to parallel 2SK28s in DEFiSIT? Do I have double transconductance? and power?
let's say that power is for 8R speakers (and especially 16R) in function of rail(s) voltage
for 4R speakers it is in function of Iq
so , paralleling , with near doubling or doubling Iq , will give benefits of increased power only for 4R speaks
for 8R speaks , you need to go higher both with rail(s) and Iq
for 4R speakers it is in function of Iq
so , paralleling , with near doubling or doubling Iq , will give benefits of increased power only for 4R speaks
for 8R speaks , you need to go higher both with rail(s) and Iq
Hvala vam!
One more question, what is the relationship of votlage ditribution of SIT and FET? Is just half-half the best?
you mean - exact voltage level of output node ?
little hard to check that with ears only , but much easier if you can use both THD spectra measurements and ears , so you can vary value of interest , then compare measured (THD ) and listening tests
let's say that half/half between SIT and mosfet is good point to start , then vary it few volts down and few volts up
little hard to check that with ears only , but much easier if you can use both THD spectra measurements and ears , so you can vary value of interest , then compare measured (THD ) and listening tests
let's say that half/half between SIT and mosfet is good point to start , then vary it few volts down and few volts up
@Gerd
I use windows. Do you have any recommended software?
Per comment from ZM regarding rail(s) and Iq, I tried to increase the -V to 48V for the same 1.5A current. (Both 0.66 ohms Source resistors)
channel A : Vgs -5.59V Vds 27.3V (oh...)
channel B : Vgs -5.47V Vds 12.2V
It is not an easy job of matching and is different per different condition. I think even the matching is done at a static voltage and current, the dynamic condition can be quite different?
I use windows. Do you have any recommended software?
Per comment from ZM regarding rail(s) and Iq, I tried to increase the -V to 48V for the same 1.5A current. (Both 0.66 ohms Source resistors)
channel A : Vgs -5.59V Vds 27.3V (oh...)
channel B : Vgs -5.47V Vds 12.2V
It is not an easy job of matching and is different per different condition. I think even the matching is done at a static voltage and current, the dynamic condition can be quite different?
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I can recommend for Windows
freeware: Visual Analyser with its visual analyses
of course the famous ARTA, a bit more complicated
or 30days trial: Multi-Instrument, a powerful multi-function virtual instrument software - Virtins Technology
It is always some work to get accommodated to a program like this.
You must dampen the signal going from speaker output and his 8 Ohm resistor load.
with a small resistor network.
reason, normal sound cards have their input limit at 2V and even measuring 1W at 8 Ohm demands 2.83V at an 8 Ohm load.
You find many hints for damping when you google "thd measurements sound card"
I add a picture from the ARTA manual.
R1 is 820R
R2 is 100R
so you get around 20dB damping.
freeware: Visual Analyser with its visual analyses
of course the famous ARTA, a bit more complicated
or 30days trial: Multi-Instrument, a powerful multi-function virtual instrument software - Virtins Technology
It is always some work to get accommodated to a program like this.
You must dampen the signal going from speaker output and his 8 Ohm resistor load.
with a small resistor network.
reason, normal sound cards have their input limit at 2V and even measuring 1W at 8 Ohm demands 2.83V at an 8 Ohm load.
You find many hints for damping when you google "thd measurements sound card"
I add a picture from the ARTA manual.
R1 is 820R
R2 is 100R
so you get around 20dB damping.
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Thank you for letting me know when to stop.
I appreciate the recommendation. I will take time and try to get to know them!
Please understand that I was not good at school.
I checked what I have as measuring tools. There are oscilloscope and simple audio signal generator. I tried this only once long ago..
I appreciate the recommendation. I will take time and try to get to know them!
Please understand that I was not good at school.
I checked what I have as measuring tools. There are oscilloscope and simple audio signal generator. I tried this only once long ago..
Hi Gerd,
Honeymoon.. what can I say. Once a woman is yours, you tend to care less.
But that does not mean that she is ugly now.
I am listening to it right now. Good thing is that this amp even sounds good with String Quartets to Altec horn speakers. Musically balanced (what does it mean..?) I think. I cannot complain!
I threatened Nelson for firm order acknowledgment and he replied that it will be OK. I will be happy with the real one I hope. In fact, I'm just satisfied by the fact that somehow I made this working DEFiSIT.
Finetuning an amp is not something I can do easy..
Honeymoon.. what can I say. Once a woman is yours, you tend to care less.
But that does not mean that she is ugly now.
I am listening to it right now. Good thing is that this amp even sounds good with String Quartets to Altec horn speakers. Musically balanced (what does it mean..?) I think. I cannot complain!
I threatened Nelson for firm order acknowledgment and he replied that it will be OK. I will be happy with the real one I hope. In fact, I'm just satisfied by the fact that somehow I made this working DEFiSIT.
Finetuning an amp is not something I can do easy..
@ ChulI did make a mistake today and my DEFiSIT amp worked!
I used my last pair of 2SK82 and IRFP9240....The heat sink size is not enough....
If two heat sinks are separate with lots of space & distance in between, and in " flying in the air " position,
I mean up, only little physical contact with wood, then You use them in optimal conditions IMHO.
What about autoformer voltage gain stage?
Congratulations interesting work!
Best regards
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@ Chul
If two heat sinks are separate with lots of space & distance in between, and in " flying in the air " position,
I mean up, only little physical contact with wood, then You use them in optimal conditions IMHO.
What about autoformer voltage gain stage?
Congratulations interesting work!
Best regards
Thank you Soundhappy,
It was a breadboard wiring and no final build.
All I want to do is 'taste' the DEFiSIT, so no (time to use) autoformer.
My DAC output is high and speaker is sensitive one. So there is only DEFiSIT circuit between DAC and the speakers.