Hi ,everybody!Nice to meet you throug the net.
Last year I had tested ablout 100 pieces of irf9610s with the method on web passdiy.com. The difference between the mosfets is small, the biggest tolerance is less than 10mv.I'm sure ,it's true.Through the test I got 8 couple of mosfet.In December I'd made the Aleph3. The DC offset of the both channels is around 60mv.In despite of very much effort I paid ,it i was no use.I cann't understand it. Recently I want to built the Aleph X. Is there any better way to match the irf9610?Any suggestion will be apreciated.
THX a lot.
Last year I had tested ablout 100 pieces of irf9610s with the method on web passdiy.com. The difference between the mosfets is small, the biggest tolerance is less than 10mv.I'm sure ,it's true.Through the test I got 8 couple of mosfet.In December I'd made the Aleph3. The DC offset of the both channels is around 60mv.In despite of very much effort I paid ,it i was no use.I cann't understand it. Recently I want to built the Aleph X. Is there any better way to match the irf9610?Any suggestion will be apreciated.
THX a lot.
deming8418 said:
First of all 60mV is not that bad! Since when everybody, myself included, must now have 0 Vdc to be happy?
Anyways, for matching the 9610 I use 15 V and a 680 ohm bias resistor and let the transistor warm up for 5 min before reading the VGS I leave the room while it's warming up to avoid disturbing the set up. For the power Mosfet I use a 50 ohm resistor to bias.
I don't know how much the tranconductance changes between mosfets. However, I ended up substituting a mosfet that read a little bit different Vgs from the one that measured perfectly identical Vgs because it had a higher Rds for equal amount of bias voltage and equal value of source resistors.
By the way what kind of source resistors are you using? You can put them in a circuit and match those as well.
I wouldn't freak out about 60 mV, you can improve by measuring the rds and swapping the mosfet that measure a little bit different.
OK... time for an update. Once again, I apologize for taking so long with the spare boards. Work has been out of control the past couple of weeks, and I've barely had time to even browse the forum. I anticipate working considerable overtime until at least the end of the month, so please don't expect to receive individual replies to emails regarding Aleph-X boards. I will try and send out a mass email when the time is right. In any case, here's the latest:
I've spoken with my sales rep at Advanced Circuits about getting the production overage, but unfortunately, there was none. AC had shipped everything they produced on this order (presumably because of the little "discount" resulting from a boo-boo on their website). So, that's it for this round, I'm afraid... which means there are only 18 boards available.
I'll be selling these in quantities of 2 in a lottery to be held at the end of the month. For the lottery, I'll create a wiki page listing all the entrants I have received email from so far. Please wait till I post a link to the wiki in this thread, then look to see if your username is listed. If not, you can add it in at that time.
I am giving serious consideration to another production run, due to the very high level of interest in these boards. Do be aware that another production run would take at least two months to work through... collect orders and payments, 4-weeks production time, and then time to pack and ship. However, I have NOT yet committed to this, so please do not email me asking about it! IF I decide to do this, it will be at least mid-March before I get to it, and I will post an announcement at that time.
...Unless someone else steps forward to handle collection of payments and re-shipping...
I've spoken with my sales rep at Advanced Circuits about getting the production overage, but unfortunately, there was none. AC had shipped everything they produced on this order (presumably because of the little "discount" resulting from a boo-boo on their website). So, that's it for this round, I'm afraid... which means there are only 18 boards available.
I'll be selling these in quantities of 2 in a lottery to be held at the end of the month. For the lottery, I'll create a wiki page listing all the entrants I have received email from so far. Please wait till I post a link to the wiki in this thread, then look to see if your username is listed. If not, you can add it in at that time.I am giving serious consideration to another production run, due to the very high level of interest in these boards. Do be aware that another production run would take at least two months to work through... collect orders and payments, 4-weeks production time, and then time to pack and ship. However, I have NOT yet committed to this, so please do not email me asking about it! IF I decide to do this, it will be at least mid-March before I get to it, and I will post an announcement at that time.
...Unless someone else steps forward to handle collection of payments and re-shipping...
I wouldn't want to deprive anyone else a shot at availible boards, (I have way too many unfinished projects now) but I would buy 8 if a new order is placed. I need to finish my Aleph 2's, buy and build Dale's volume control, finish my speakers, and buy and build daisylazer's cdpro2. I need to sell my car, house and boat, and quit working and finish these projects. A man has to keep his priorities in line.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.