Aleph-X Official PCB rev Beta & 1.0

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#181
Peter Daniel said:
You need only 8 MPSA so the saving on them is neglectable.😉 As to the output mosfets it's better to find somebody who would buy the whole lot and do measurements as well and then sell matched sets.😉

I've already taken care of mine.
Click to expand...

heh... memories of last time I did matching, I spent 5 minutes a device for 120 devices... and the worth part was that halfway through, I went to lunch, and forgot to save on my network share, and lost all of the measurements and had to start over again. I just came back the next day, and was in lab from 8am until 9pm matching mosfets in the school lab. I did manage to soldier my bosoz, my 2 superamp boards and work on a pcb layout while living by the clock (stop watch). Then... a week later on the forum, people talked about how you only need to wait 5 seconds a device. I am going to test match some devices, doing them for 5 seconds for a batch of 10, then do it again for 5 minutes, and see how it works out.

My only concern is that they change a lot in the first few minutes, and by the time that 5 minutes come by, they are damn hot (burned my fingers a few times, and use a clamp to remove them from the testing socket that I used after the first few times), but the Vgs value had settled and was changing at a much much slower rate.

Anyway, I am not trying to start another long drawn out conversation on matching. If you order large amounts of mosfets, digikey gave me them all from the same batch, and they matched rather well.

--
Brian

EDIT: sorry for the confusion, I posted this from my roommates computer, and didn't realize that he was logged in
 
#182
JordanG said:


heh... memories of last time I did matching, I spent 5 minutes a device for 120 devices... and the worth part was that halfway through, I went to lunch, and forgot to save on my network share, and lost all of the measurements and had to start over again. I just came back the next day, and was in lab from 8am until 9pm matching mosfets in the school lab. I did manage to soldier my bosoz, my 2 superamp boards and work on a pcb layout while living by the clock (stop watch). Then... a week later on the forum, people talked about how you only need to wait 5 seconds a device. I am going to test match some devices, doing them for 5 seconds for a batch of 10, then do it again for 5 minutes, and see how it works out.

My only concern is that they change a lot in the first few minutes, and by the time that 5 minutes come by, they are damn hot (burned my fingers a few times, and use a clamp to remove them from the testing socket that I used after the first few times), but the Vgs value had settled and was changing at a much much slower rate.

Anyway, I am not trying to start another long drawn out conversation on matching. If you order large amounts of mosfets, digikey gave me them all from the same batch, and they matched rather well.

--
Brian
Click to expand...

should have been from this account...

--
Brian
 
#183
If anyone's interested, I matched 125 FETs using precise, by the clock, 1 minute intervals. Since time changes the FET's temperature, it seems that the exactness in time is what matters. A fellow member of this forum purchased about 25 FETs from me and tested them to his satisfaction. He complimented my accuracy, so perhaps I'm correct.
 
#186
Peter Daniel said:


I'll make my move tomorrow. Any last minute questions I should ask?😉
Click to expand...

Just to figure out how to deal with sending in money. If it would be possible to pay them directly using credit cards, this would be the easiest way. I would hate to have you accept canadian money orders and have to deal with a lot of money for such a large order.

Thanks again for organizing this.

--
Brian
 
#187
Peter Daniel said:


I'll make my move tomorrow. Any last minute questions I should ask?😉
Click to expand...

Peter,

Please post a message on the heatsink thread indicating
the cutoff for ordering and any other relevant information.
Perhaps this info can be copied to the wiki as well.

Thanks again for organizing this.

Cheers,
Dennis
 
#189
Re: Mounting mosfets for testing

Dennis Hui said:
Hi there,

How do you mount your mosfets for testing? For TO-3's
and TO220 devices, sockets are readily available. But
I can't seem to find sockets for TO3P/TO-247 devices. 🙁

Any suggestions?

Dennis
Click to expand...

I took apart some molex connectors that were used in a pc power supply, and used the female part, then just had 3 wires seperate with the female connector part, then just slid them on the devices each time. It worked fine. If I remember, someone had a better idea for this and posted pictures a while back.

--
Brian
 
#191
This is one option. You can get it from Sayal.
 

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#195
Just a quick note to say that the board production is going to take slightly longer than I had originally anticipated, since I submitted the gerbers a couple days later than scheduled, and also since I forgot to include their Christmas holidays in the production lead time. The boards will be complete by January 24th, and I will have them on the 26th.

Also, I wanted to mention that I received a couple of payments in the mail just before I left for vacation. I didn't have time to send out emails that I had received these, so please wait until I'm back on Jan 14th to see if you get a reply from me then.
 
#196
Woo hoo! The PCBs have shipped from the factory ahead of schedule! I should have them in my hands on the 15th or 16th, waaay ahead of the anticipated completion date of Jan 24. 🙂

So, that means most orders should be packaged and prepared for shipping over the coming weekend, and will likely go to the post office on Monday the 20th.

Also, I just got home, and there's a big stack of mail waiting for me, most of which look to be payments, so it will take me some time to get settled back in and filter through this. I'll send an email to everyone who's payment has arrived if I have not already done so.
 
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