allFET circlotron

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I like this:

558709d1467900140-allfet-circlotron-screenhunter_-jul.-07-15.46.jpg


This is the global feedback one right?
 
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Well strated the pcb making, here X are the components with smt also, Have ordered smt zeners and smt capacitors.

Thanks for the update. Looks like you are going to let it auto route based on air-connects? I notice you are using terminal blocks for power supply in and speaker outs. I really do prefer the 5mm pitch 0.250in spade type solder quick connects that most people use for high current power connections on amps. They are very low profile secure and easy to use.
Thanks,
X
 
Hi X

I go route manual, i never let it autoroute, do not work. Th air connects are for so I make no mistakes and can put parts on the best place
making these airwires short as possible.

The connectors you see can fit your preferred connector, it as 2.5 and 5 mm pitch but look different on photo.

the input is the same, it has 2.5 mm pitch for the bold connector, but can also be 5 mm if you want, both can be bought on ebay, 2.5 is smaller.

regards
 
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Some idea of the pcb, this way it can be small.

see picture of part with power and vas.

I can remove the fuse holders, you can then implement them in supply
making it a little smaller, for here it make routing some more easy.
 

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Founder of XSA-Labs
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Have received the mosfets, I have irfp240 and irfp250 types, picture are irfp250.

very cheap. 200 volts 30 amps. 0.039 ohm on.

Do not now or these are genuin, but looks good..

What did you pay for them? They look a bit flat on the front - mine seem to have more of a 3D appearance. We will see once we run them though. If you look at my IRFP's as installed on FH9HV, these are from Aliexpress China (5 pairs for $5.76) but are genuine. I pushed them hard at 120w into 8R load and 52v rails and still singing. Note the recessed flat area in middle where text is printed. On yours it is all flat. Hmmm...

Layout is taking shape and looking good. The fuse holders are fine as long as board stays under 100mm X 100mm. Can you make all transistors mounted on heatsink symmetrically mounted so heat generation and pickup by VAS is uniform? Just slide the IRF610's and IRF4905's little to the right.

Thanks.

559048d1468069656-allfet-circlotron-image.jpeg
 

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Kees,
The gate pin on IRF's is pin 1. Maybe you will still reconnect to proper pins but layout shows 220R gate resistors going to pin 2.

X it will go good at last, I do intens look at errors, like the pinouts of mosfets, it is just a xample how and what is best, the airwires
do sometimes get different in eagle, I need then to update erc then you can see it is oke.

If the irfp,s are genuin I do not now, I do now it is coming very fast with a airplane.

I have irfp 240 who are like yours are with print of name, if mine are not genuine seller get trouble with paypal..
 
Have you looked at the FFT simulation comparing the harmonic ratios between the LTP version and the non-LTP front end version?

here are the differences with multisim.

all three, first is front end and the two second are full and local feedbacked with same schematic if you did mean this...

I have to say, build and measure realtime is the best way, simulations of harmonics fourier is not always accurate.

The middle is local feedback and the last is full feedback of second design, I can not say design because all amp things are
already invented in time, I do combine them and see new things I hope.

regards
 

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Only way to know for sure is to test it in an amp with high power. Another way is to measure the capacitance between the die (source) and gate. A fake uses a tiny FET embedded inside the large epoxy body. So a fake will have a smaller capacitance vs a real one. But you need an AC capacitance meter.

The images I have managed to get off the internet for International Rectifier IRFP's all seem to have a smooth window on which the text is etched. There are three circular plastic injection holes on the front as well. I hope it works for you.

1438-500x500.jpg


Vs the ones you got:

$_1.JPG
 
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I got some fake 2sc5200 and 2sa1943's once. They burned out upon use. Seller told me we never had any issues before and always sell out of them. They refunded me half my money because I did not show that all 10 bad (just 5 blew up). This is the only fakes I have run into though. The 36 types of other transistors (including 2sk1058 2sj162 lateral FETs and 2sk170's and IRFP's) I have bought from Aliexpress have been good. So pretty good odds. Even hard to find KSA1381 and KSC3503's have been excellent.
 
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I got some fake 2sc5200 and 2sa1943's once. They burned out upon use. Seller told me we never had any issues before and always sell out of them. They refunded me half my money because I did not show that all 10 bad (just 5 blew up). This is the only fakes I have run into though. The 36 types of other transistors (including 2sk1058 2sj162 lateral FETs and 2sk170's and IRFP's) I have bought from Aliexpress have been good. So pretty good odds. Even hard to find KSA1381 and KSC3503's have been excellent.

Aliexpress is as such a better place to Buy? if payal can be used I go look there.

here I have done a FFT with ltspice on all the designs, the kaneta reviced version did have higher values of distortion, I am a little stunned about the first version balanced who have a very low distortion without the feedback, or better with the local feedback.

So we have a better picture because ltspice do a lot better sim that then multisim. pictures are in following order, amp his FFT, etc.

On the last one you can see the balanced aktion on distortion, the oneven harmonic's are some higher but still -60 dB. the others have single ended drivers and as such it has higher harmonics.

regards

kees
 

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