Does one heatsink look like enough for one Mosfet? They're pretty heavy, 1.3kg. On the other hand if I bolted 4 together it would leave a good amount of space inside. I don't need much power, but I might alter the MoFo at a future point.
How good would the dissipation be if I did mount the Mosfet on the middle piece sticking out?
How good would the dissipation be if I did mount the Mosfet on the middle piece sticking out?
I finally found some time to install the meanwell psu on my mofo-mini. However, I forgot to reset the potentiometer for the higher V on the PSU, and the poor mosfet released its magic smoke and went to the big rig in the sky
So it was an opportunity to install an IRFP510 instead of an 610
The new mosfet is now slowly cooking on the kitchen bench. I am aiming at 0.4A at 20.1V (min of the LRS-75-24), which should rise a bit with a closed chassis.
Hopefully I will manage to find some time to test it with some riffs soon.
I am still doing some revisions on my PSU and preamp boards. I will post more soonish
So it was an opportunity to install an IRFP510 instead of an 610
The new mosfet is now slowly cooking on the kitchen bench. I am aiming at 0.4A at 20.1V (min of the LRS-75-24), which should rise a bit with a closed chassis.
Hopefully I will manage to find some time to test it with some riffs soon.
I am still doing some revisions on my PSU and preamp boards. I will post more soonish
A few thoughts.
Biased with 20.1V @0.4A, and an input at a bit less than 3V (1W rms ish), the output seems to be very nice and clean. I have no distortion analyzer, I just see the output wave form. Above that, I start seeing visible clipping on the negative side. At around 6V the amp is close to 5W, and the negative is very clearly clipped. That hardly would qualify as high fidelity, but it is a very interesting behavior for my application which is a guitar amp. It looks very much like the asymmetrical clipping that things like cold cathode clipper try to do. I doubt the flimsy aluminum is enough for that much heat though, so I did not explore this any further for now. And this is a discussion for the instrument forum.
For this revision, I was going for a super clean amp at around 1W, and so far this seems to work excellently. And the volume range on my test speaker when using one of my preamp pedals seems perfect for home use.
I am also super happy with the Meanwell LRS which does not have such a good reputation. As I said, the amp is completely silent, even with the high db guitar speaker.
Biased with 20.1V @0.4A, and an input at a bit less than 3V (1W rms ish), the output seems to be very nice and clean. I have no distortion analyzer, I just see the output wave form. Above that, I start seeing visible clipping on the negative side. At around 6V the amp is close to 5W, and the negative is very clearly clipped. That hardly would qualify as high fidelity, but it is a very interesting behavior for my application which is a guitar amp. It looks very much like the asymmetrical clipping that things like cold cathode clipper try to do. I doubt the flimsy aluminum is enough for that much heat though, so I did not explore this any further for now. And this is a discussion for the instrument forum.
For this revision, I was going for a super clean amp at around 1W, and so far this seems to work excellently. And the volume range on my test speaker when using one of my preamp pedals seems perfect for home use.
I am also super happy with the Meanwell LRS which does not have such a good reputation. As I said, the amp is completely silent, even with the high db guitar speaker.
Quick question on my mofo builds and maybe just a bad pairing.
I built a simple setup with 19V Dell laptop supplies and 193T chokes. One issue I experienced is with a Pass x2.5 preamp. When the volume is turned all the way down, it’s put on mute, or the unit is turned off, there is a weird motor boat sound from one of the speakers after the preamp clicks to 0. If I change the power supply to the other channel it follows that specific supply.
No other issues on the other preamps I played around with. I’m guessing bad Dell power brick but I also wonder if I need to correct wiring. I cut the ends off to replace with 2.1 x5.5mm plugs. Cutting the ends off it exposes 3 wires.
One is ground, the other is positive and I have no idea what the last one is so I just left it floating. I’m curious if that wire needs to be hooked up still.
I built a simple setup with 19V Dell laptop supplies and 193T chokes. One issue I experienced is with a Pass x2.5 preamp. When the volume is turned all the way down, it’s put on mute, or the unit is turned off, there is a weird motor boat sound from one of the speakers after the preamp clicks to 0. If I change the power supply to the other channel it follows that specific supply.
No other issues on the other preamps I played around with. I’m guessing bad Dell power brick but I also wonder if I need to correct wiring. I cut the ends off to replace with 2.1 x5.5mm plugs. Cutting the ends off it exposes 3 wires.
One is ground, the other is positive and I have no idea what the last one is so I just left it floating. I’m curious if that wire needs to be hooked up still.
@Dneu2011 I bought two cheap "laptop power supplies" for my MoFos. Neither were adequate for the task, and kept trying to reset. Perhaps this is causing the "motorboat".
Upgrading to brand new Asus laptop power bricks fixed my issue, and those have been running well for several years now.
Kind regards,
Drew
Upgrading to brand new Asus laptop power bricks fixed my issue, and those have been running well for several years now.
Kind regards,
Drew
thanks for the feedback. What is weird is it only does it when the volume is turned all the way down on two different preamps. One was a Pass X2.5 and the other was on my Musical Paradise dac used as a preamp.
I tried 3 other preamps and didn’t have this issue.
Although, today I was troubleshooting and put some really nice Tara Labs rcas between the amp and my Musical Paradise and the sound went away. I am thinking it could have been a grounding issue. I will keep checking and try new laptop supplies if it comes back.
I tried 3 other preamps and didn’t have this issue.
Although, today I was troubleshooting and put some really nice Tara Labs rcas between the amp and my Musical Paradise and the sound went away. I am thinking it could have been a grounding issue. I will keep checking and try new laptop supplies if it comes back.
I found even looking at Mouser you can't tell what you are getting. So, I bought at the store. If they don't work, return. I'm running 24V, 193V chokes. MonoBlocks, 2 pr. 4 meanwell bricks. I got Switchcraft barrels at Mouser. There is an Amazon hack in the thread to mod cables. Switchcraft are as stated for very fine wire. I used 18G solid.
Always check the part number and the datasheet that goes with it. Never trust images
Yet, even Mouser Techs can't confirm on so many parts. There is a time you order as it is the only way. Then return. Mouser is good on returns. I had to call them on this and the store was my only option.
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^ 
I've sent Mouser two notifications for incorrect data sheets...
There is a little exclamation point with "See an error?" in the upper right below the cart.
In both cases, the errors were on the manufacturer, but Mouser made it right.
Double... triple check.
As a newer person to electronics, that's why I always like to use parts purchased and tested by others. The same nomenclature for a part... may be a different part... can be a nightmare to troubleshoot.
Also, those little Mega testers are the cat's a$$.
I've sent Mouser two notifications for incorrect data sheets...
There is a little exclamation point with "See an error?" in the upper right below the cart.
In both cases, the errors were on the manufacturer, but Mouser made it right.
Double... triple check.
As a newer person to electronics, that's why I always like to use parts purchased and tested by others. The same nomenclature for a part... may be a different part... can be a nightmare to troubleshoot.
Also, those little Mega testers are the cat's a$$.