pictures of his car, too
it would be nice to have it in my car also... at least I could use water radiating system to cool the mosfet Why on earth are you not connecting a load? Pretend it's a tube amp. This is a non-problem.
Out of curiosity, my PCB includes a bleeder on the output. Are you using one?
In fact, it might be better if you share some information about your build, perhaps even some pictures.
Yes, I know it's not normal to use the amp without a load. I simply found that it can happen for a mistake (as it happened to me) and also if it is for few seconds, it can cause same damage.
I'm using a custom PCB; I've just verified that the 1 kohm resistor is present between the output terminals, as reported on your schema. Maybe I could add a lower resistor (56 or 68 ohm / 5W for example) or simply protect the MoFo with a fast fuse...
Hi Zen,
I am testing amps, especially this one, with 8 ohm load almost at full power with square wave. Mofo style performs well. But I wonder, what is the power/voltage level with square wave. 2.83V or frequency ? 1KHZ, 5-10, or 20KHZ... ?
Which test condition must satisfy me ?
I have the obsession that at 20Khz with full load the amp must give perfect sq wave response.
Thanks.
Regards
Mehmet
I am testing amps, especially this one, with 8 ohm load almost at full power with square wave. Mofo style performs well. But I wonder, what is the power/voltage level with square wave. 2.83V or frequency ? 1KHZ, 5-10, or 20KHZ... ?
Which test condition must satisfy me ?
I have the obsession that at 20Khz with full load the amp must give perfect sq wave response.
Thanks.
Regards
Mehmet
I don't think so, I can ordinary use (big) MoFo for quite a long time with this... and the problem with missing load arise immediately if I disconnect the speakers. I will recheck my circuit anyway, thanks a lot for your work 🙂
I use this procedure to reproduce the problem, but of course I don't expect it to happen often, hopefully. I discovered it with an error I made while I was measuring MoFo at the oscilloscope, so I was just wondering if there is a simple/elegant solution to avoid that *accidentally* disconnected load during ordinary operation could break my great MoFo 😅
BTW I'm using 2.5A@24V with Hammond 193V chokes. And I would anyway repeat that I find this amplifier simply Great both at measures and at listening!
Today I went to check the performance degradation by reducing the inductance value in the simulation and I have seen that already with 50mH you can see some problems (here the sine plot at 20Hz)
In the simulation of the output stage at 40Hz we have a thd of 0.7% instead of 0.1%.
Follows also the 4 measurements of the complete amplifier with 195T5 at 40Hz, 100Hz, 1KHz and 10KHz
In the simulation of the output stage at 40Hz we have a thd of 0.7% instead of 0.1%.
Follows also the 4 measurements of the complete amplifier with 195T5 at 40Hz, 100Hz, 1KHz and 10KHz
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Why use a linestage with feedback to drive a pure class A current amplifier ?
I think that the best solution is use vacuum tube for the voltage amplifier.
I can share files to produce my pcb with an integrated power supply.
It can be used with 12AX7 and 6072A.
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I am driving big MoFo with a slightly modified version of the "bride of zen" by Nelson Pass (I simply bypassed the 10 uF output capacitance since MoFo has a 2,2 uF input cap is unuseful to duplicate, and I changed R108/R208 to 27 ohm in order drive big MoFo with 1 Vpp for full power out).
In this way I have a two-stage single-mosfet class-A single-ended zero-feedback system. Sound is stunning!
Claudio
Hello I am here with new measurements using ADALM2000.
I don't see big differences from my PF2019 so therefore there are no negative effects using the inductance instead of the current generator on the source of the mosfet.
I don't know why the slew rate is low in both the amplifiers, Pathos declare value of 38V/usec here.
T.T.
I don't see big differences from my PF2019 so therefore there are no negative effects using the inductance instead of the current generator on the source of the mosfet.
I don't know why the slew rate is low in both the amplifiers, Pathos declare value of 38V/usec here.
T.T.
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