I run a bipolar so I would try about 45V and about 90V both and correct I would limit the voltage of the capacitors which were too expensive at 100+ volts. I may also use this for other purposes ans amps
Simulation takes too long when I added the PSU into account. Before that it was running fast. Output FET is IXYS IXTH6N50D2. I found the models for IXYS in this site and i think IRFP on vendors site.
I destroyed the IXYS FET.
I upload one better picture, I have added there the XO from speakers nd PSU, also a second channel which doesn't show so we have better view.
Simulation takes too long when I added the PSU into account. Before that it was running fast. Output FET is IXYS IXTH6N50D2. I found the models for IXYS in this site and i think IRFP on vendors site.
I destroyed the IXYS FET.
I upload one better picture, I have added there the XO from speakers nd PSU, also a second channel which doesn't show so we have better view.
Attachments
https://ixapps.ixys.com/DataSheet/DS100177B(IXTA-TP-TH6N50D2).pdf
SOA from data sheet:
Note that for DC operation at case temperature 75 C, 2.0A at 90VDC.
SOA from data sheet:
Note that for DC operation at case temperature 75 C, 2.0A at 90VDC.
Attachments
@Stanislav
This FET is supposed to be autobiased but you are right, I intend to put a potentiometer and a resistor in source in order to go to 2.2V, where Nelson has found a sweet spot at 100V, we ll see. A resistor between G and D? Like a feedback?
The 221 ohm is in series with input signal, right?
@PRR, this zener will looks from S to G, right? And what value?
@Ben I am not sure how to read this, what I can read is that for 75 C 4A and 100V I am safe (?), I understand I am safe below the lines right, I am not sure about the pulses. I am also a little concerned about this FET, I am ordering IXTH16N50D2, which has 16A nominal, since I am afraid some peaks may go over 6A.
This FET is supposed to be autobiased but you are right, I intend to put a potentiometer and a resistor in source in order to go to 2.2V, where Nelson has found a sweet spot at 100V, we ll see. A resistor between G and D? Like a feedback?
The 221 ohm is in series with input signal, right?
@PRR, this zener will looks from S to G, right? And what value?
@Ben I am not sure how to read this, what I can read is that for 75 C 4A and 100V I am safe (?), I understand I am safe below the lines right, I am not sure about the pulses. I am also a little concerned about this FET, I am ordering IXTH16N50D2, which has 16A nominal, since I am afraid some peaks may go over 6A.
Changed switches and now I can have cooling on without main power on. I tested many times on off switching no issue.
Today it played music. I haven't installed the preamp yet, since listening room is under construction too but this week will happen.
I drove it with a very old Sony CD player XA20ES, which by the way has a volume control and fed an 8 Ohm $100 old speaker, these were available at the "lab" room. I put Army of Lovers it was the only CD around
First impression is that it managed to reach a good sound level without preamp at a rather insensitive cheap speaker. Sound was detailed and i was impressed by bass and middle. No curtain, voices were there near me. I was expecting a little better in highs, maybe CD player creates bad filter with the amplifier. However, everything was crystal clear and little details that I haven't heard before were very sound before me. To be honest I didn't expect this to be working lol but so far so good.
I intend to work for a week on the cheap equipment in order to see if any issues arise and also start building the second channel on another chassis.
Let's hope it will manage to drive the big Maggies in the end with the help of my 1 Ohm output preamp.
I let it play for two hours and I got 67 C, ambient 29 C. Cooling was at the very low. Depending on the result I may drive the FET even higher and throttle cooling.
Today it played music. I haven't installed the preamp yet, since listening room is under construction too but this week will happen.
I drove it with a very old Sony CD player XA20ES, which by the way has a volume control and fed an 8 Ohm $100 old speaker, these were available at the "lab" room. I put Army of Lovers it was the only CD around
First impression is that it managed to reach a good sound level without preamp at a rather insensitive cheap speaker. Sound was detailed and i was impressed by bass and middle. No curtain, voices were there near me. I was expecting a little better in highs, maybe CD player creates bad filter with the amplifier. However, everything was crystal clear and little details that I haven't heard before were very sound before me. To be honest I didn't expect this to be working lol but so far so good.
I intend to work for a week on the cheap equipment in order to see if any issues arise and also start building the second channel on another chassis.
Let's hope it will manage to drive the big Maggies in the end with the help of my 1 Ohm output preamp.
I let it play for two hours and I got 67 C, ambient 29 C. Cooling was at the very low. Depending on the result I may drive the FET even higher and throttle cooling.
I assume that is from http://www.firstwatt.com/pdf/art_delite.pdf De-Lux De-Lite.
The De-Lux De-Lite has a 100VDC supply but it also has a 300W bulb, not a Hammond 193V choke:
"As the light bulb glows brighter, the distortion continues to decline and the power
increases. And the transistor runs hotter, so take care that you have enough
heat sink. We are getting into the 50 to 60 watt dissipation territory for devices
which are rated at 300 watts, and with care mounting the transistor, it should be
plenty fine if you can put your hand on the sink for 10 seconds (50-55 deg C)".
Also:
"We can do much the same for the IXTH6N50D2, and Figure 10 shows the circuit
of Figure 7 at 100V DC and 2.2 A. This requires a Gate voltage in between the
Source and Ground voltage, so we adjust the input bias with a potentiometer as
shown. Typically a 10K pot will end up being adjusted for about 25V DC at the
Drain of the transistor."
So Vds is 25V-2.2V= 22.8V, Iq=2.2A, power dissipation = 22.8V x 2.2A=50.2W.
You are running your device much hotter.
Yes, correct, it's from there the idea. i know it has bulb, I want to try the 193V and see what happens.
I measured again today with the correct multimeter and i have 90V reaching the FET and 1.8V across the Rsource, so we have 3.6 A. That gives us 324 Watts. And I can get them out of the FET. So no issue I guess. I will build a CCS too for that amperage to see if it will improve things. In general that was the idea for this project, to see how much heat i can dissipate. And to scare you more, I intend to use a second liquid cooler and increase things even worse, with other FETs coming already
I measured again today with the correct multimeter and i have 90V reaching the FET and 1.8V across the Rsource, so we have 3.6 A. That gives us 324 Watts. And I can get them out of the FET. So no issue I guess. I will build a CCS too for that amperage to see if it will improve things. In general that was the idea for this project, to see how much heat i can dissipate. And to scare you more, I intend to use a second liquid cooler and increase things even worse
, with other FETs coming already I have obtained 20n20, ixth6N50D2, ixth20N50D2, IRFPs... etc and I am playing. It is very fun to play with basic circuits. For example, I put the EXICON (it is a very nice lateral FET...) and Nothing was happening... Then I put a battery in source-gate and then *boom*, current was running! I am playing and measuring everything and trying to understand what is happening and I am studying the curves to see how close these are.
I ordered from Mouser and it is impressive, stuff was here in three days!!
One question. Can I measure a FET with an Ohmmeter? I am measuring but I see too low resistance from G to D (0.6), which sounds normal and then I measure from D to G (on a specific set) and I get same measure. Shouldn't on the other direction show very big resistance? (G to D,R very big resistance)
I ordered from Mouser and it is impressive, stuff was here in three days!!
One question. Can I measure a FET with an Ohmmeter? I am measuring but I see too low resistance from G to D (0.6), which sounds normal and then I measure from D to G (on a specific set) and I get same measure. Shouldn't on the other direction show very big resistance? (G to D,R very big resistance)
After may experiments and some burnt FETs, I have now put the system to 55V, 1 Ohm. Vs is 2.2V, so we are at 2.2A. I have ordered 0.8 Ohm resistors, so I will also try also this. Heat dissipation is 120W. Vd is 47V. Temperature with mild cooling is 50 C. Unfortunately next step on PSU is 110V, which has many instability issues. I am building a variable 80V, 10A PSU, which will permit me for more experiments.
I have the opportunity to listen to music about an hour again on cheapo peripherals and put for a minute the magnepans, I have built only one channel
Well,
- Magnepans couldn't be driven, period, however
- On cheapo I liked what I was listening. VERY controlled and nice bass, with enough volume, impressive!
- For the source playing (Sony CD without preamp), there was no curtain
- Nice middle area, very clear voices, you can see the details there
- High area good but not top. Maybe the cheapospeakers' fault, maybe the no preamp. I will have to move the preamp at last to the lab to listen with preamp. However, there was certain info coming there in the highs that was not heard before (!) on other systems, or it was too "in front" now and could hear it clearly.
- I have built a very nice PSU. I have no humanything. Amp is ultra quiet.
- In many organs, rich info, there seemed to be a little (very low) mess, I believe it is lack of power. In these times also seems slow.I believe this system needs to go a little higher in voltage and power (and maybe needs many little capacitors, instead the big ones).
- In this setup satisfactory level of volume for mono. I will start to setup the 2nd channel, now i see the setup works.
- I tried resistors, I had many resistors 50W each, combined them in parallel and series and put a blower on them. Liked the 193V better.
- In overall, it is a very musical system, I like listening to it, it is an amp I am going to keep. I believe everything will be much better with my reference other components, when this will happen. I have only half an hour available per day and that slows me down very much.
I have the opportunity to listen to music about an hour again on cheapo peripherals and put for a minute the magnepans, I have built only one channel
Well,
- Magnepans couldn't be driven, period, however
- On cheapo I liked what I was listening. VERY controlled and nice bass, with enough volume, impressive!
- For the source playing (Sony CD without preamp), there was no curtain
- Nice middle area, very clear voices, you can see the details there
- High area good but not top. Maybe the cheapospeakers' fault, maybe the no preamp. I will have to move the preamp at last to the lab to listen with preamp. However, there was certain info coming there in the highs that was not heard before (!) on other systems, or it was too "in front" now and could hear it clearly.
- I have built a very nice PSU. I have no humanything. Amp is ultra quiet.
- In many organs, rich info, there seemed to be a little (very low) mess, I believe it is lack of power. In these times also seems slow.I believe this system needs to go a little higher in voltage and power (and maybe needs many little capacitors, instead the big ones).
- In this setup satisfactory level of volume for mono. I will start to setup the 2nd channel, now i see the setup works.
- I tried resistors, I had many resistors 50W each, combined them in parallel and series and put a blower on them. Liked the 193V better.
- In overall, it is a very musical system, I like listening to it, it is an amp I am going to keep. I believe everything will be much better with my reference other components, when this will happen. I have only half an hour available per day and that slows me down very much.
Attachments
I want to bias this thing and I followed the voltage divider as per scheme and it was a total defeat. Rs smoked again, measured 13V Vs before I shut it down.... I don't understand what's wrong. Double checked it, in LTSpice it works and gives good distortion numbers.
Attachments
I answer my own question. It seems Rs needs cooling. what happened is that Vs started with 3.7V, then it got too hot and dropped resistance too low, so I was over 15A (everything hold together though . I ordered 0.5 to 1 Ohm resistors 50W, so I can put them on a heatsink.
Seems that the wattage resistors need cooling after a couple of watts.
For now changed to 1.5 30W I had and bias is at 1V. Better, sweeter sound but for now I miss power, waiting for correct resistors.
FET is at 26 C . I learnt the hard way that I must be very meticulous the way the heatsink is mounted:
- Fast mount, no arctic silver, no tightened screws. temp 70 C, damaged FET
- meticulous mount, 26 C !!
I also changed my mount way, so I can change the FET, without opening the box
- Remind to me: I must install a fuse...
(everything hold together though . I ordered 0.5 to 1 Ohm resistors 50W, so I can put them on a heatsink. Seems that the wattage resistors need cooling after a couple of watts.
For now changed to 1.5 30W I had and bias is at 1V. Better, sweeter sound but for now I miss power, waiting for correct resistors.
FET is at 26 C
. I learnt the hard way that I must be very meticulous the way the heatsink is mounted:- Fast mount, no arctic silver, no tightened screws. temp 70 C, damaged FET
- meticulous mount, 26 C !!
I also changed my mount way, so I can change the FET, without opening the box
- Remind to me: I must install a fuse...
.. to continue my monologue, Vs measures 3.87V (LTSpice shows 2.7). Heat dissipation in LTSpice shows 6W on Rs. Bias is 1.86V. Adding bias surely pushes amp more and Rs produces heat.
Now the sound. Distortion is lower indeed, I believe I am somehow reaching the limit of the cheap setup. Tomorrow I hope I ll find time to put on a preamp I had built 30+ years ago and was laying around there... Vd is 51V. 193V is a big dog, handled many times more than 3A.
Now we should be more than 120W heat from the FET, we are doing ok.
Now the sound. Distortion is lower indeed, I believe I am somehow reaching the limit of the cheap setup. Tomorrow I hope I ll find time to put on a preamp I had built 30+ years ago
and was laying around there... Vd is 51V. 193V is a big dog, handled many times more than 3A. Now we should be more than 120W heat from the FET, we are doing ok.
Thanx nico
More news. Bias now is 2.3V, Vs 3.7, I am working at 4A, 55V. I am a little afraid fro 193V, so 195T5 is already ordered from mouser. Temp of the FET is 35C (hydro cooling at lowest level),
We have music now. It proves out that my cheap speaker has vifa tweeter, not bad. I am listening very carefully at 1m from speaker. That thing makes smile. I don't know if it is the best etc, but it is very interesting. I have some volume now.
I fed it today with classical music, to three blind mile recordings (i found some old CDs... )
I have highs now and "s" is not whistling, excellent! Bass is exact, tight. It is very nice how an ending note is trebling in the air when it gradually stops, very exact.
Besides that, yes we can DISCO. We couldn't before, now we can. Put some nineties beats, very nice. Too new beats sound like crap sorry.
Magnepans still refuse to move. I intend to push more, I ll be in 300W in the end, where I will stop, we ll see If I manage to stimulate them.Tried also the cheap pre-amp. Didn't like him at all. Better highs but distortion. When I have finished the setup, I will bring on the heavy weapons.
Sound is different from NF amps. I think NF is "nicing" the sound but I don't want to start war here, i am telling only my opinion.
What is missing. Power, I would like to have more dbs. Maybe some more sensitive speakers. I have a series of non sensitive speakers, you see my RG7s are brutal. Ill push more and maybe I get more power.
I am ordering the 2nd set of parts, I want very much to make it stereo now that i see it works. I will keep the setup.
More news. Bias now is 2.3V, Vs 3.7, I am working at 4A, 55V. I am a little afraid fro 193V, so 195T5 is already ordered from mouser. Temp of the FET is 35C (hydro cooling at lowest level),
We have music now. It proves out that my cheap speaker has vifa tweeter, not bad. I am listening very carefully at 1m from speaker. That thing makes smile. I don't know if it is the best etc, but it is very interesting. I have some volume now.
I fed it today with classical music, to three blind mile recordings (i found some old CDs... )
I have highs now and "s" is not whistling, excellent! Bass is exact, tight. It is very nice how an ending note is trebling in the air when it gradually stops, very exact.
Besides that, yes we can DISCO. We couldn't before, now we can. Put some nineties beats, very nice. Too new beats sound like crap sorry.
Magnepans still refuse to move. I intend to push more, I ll be in 300W in the end, where I will stop, we ll see If I manage to stimulate them.Tried also the cheap pre-amp. Didn't like him at all. Better highs but distortion. When I have finished the setup, I will bring on the heavy weapons.
Sound is different from NF amps. I think NF is "nicing" the sound but I don't want to start war here, i am telling only my opinion.
What is missing. Power, I would like to have more dbs. Maybe some more sensitive speakers. I have a series of non sensitive speakers, you see my RG7s are brutal. Ill push more and maybe I get more power.
I am ordering the 2nd set of parts, I want very much to make it stereo now that i see it works. I will keep the setup.
Maybe but in start it is cold and I don't see much change in audio behavior. Today I am at 4V Vs, 6A, 263W, everything is cool and power is better.
Now I will just test with preamp @weekend.
I had a little buzz if you put my ear on the speakers. Put two visaton 2mH air in PSU and now ABSOLUTE silence, I put my ear on the tweeter, nothing! amazing.
Today another toy arrived, see
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