habsrock93 1
compressit 1
CeeVee 2
flocchini 1
RichLund 1
Nikola Krivorov 1
Greg Stewart 2
qusp 2
frozen wing 1
neb001 2
merlin el mago 2
lauret 2
igwt 2
ichiban 1
DaveM 1
fitzfish 2
Yunick 1
DiyFan 1
Jacques Merde 2
stephen1212 2
dggs 1
NicMac 1
pierrequiroule 1
minus 2 for me
Total 33 boards
it would have been nice to have a D1-only board too with the fets and resistors on the side for more custumization and wider appeal for maybe half the price. Or a breakeable board...
again sorry
compressit 1
CeeVee 2
flocchini 1
RichLund 1
Nikola Krivorov 1
Greg Stewart 2
qusp 2
frozen wing 1
neb001 2
merlin el mago 2
lauret 2
igwt 2
ichiban 1
DaveM 1
fitzfish 2
Yunick 1
DiyFan 1
Jacques Merde 2
stephen1212 2
dggs 1
NicMac 1
pierrequiroule 1
minus 2 for me
Total 33 boards
it would have been nice to have a D1-only board too with the fets and resistors on the side for more custumization and wider appeal for maybe half the price. Or a breakeable board...
again sorry
habsrock93 1
compressit 1
CeeVee 2
flocchini 1
RichLund 1
Nikola Krivorov 1
Greg Stewart 2
qusp 2
frozen wing 1
neb001 2
merlin el mago 2
lauret 2
igwt 2
DaveM 1
fitzfish 2
Yunick 1
DiyFan 1
Jacques Merde 2
stephen1212 2
dggs 1
NicMac 1
pierrequiroule 1
minus 1 for me
Total 32 boards
Hi Guys,
Sorry for dropping this over the past week... it has been a busy one for me job-wise. I've got a pretty big career change on the go, so the next few weeks are going to be hectic.
Just the same, I'd like to get all these Gerbers sent out so that I can focus on other things while the boards are being made.
I've noticed a few people drop out of the board purchase, so I'm going to order 40 and call it at that. I'll see what the PCB fab can do for pricing with that number of boards.
I hope the prices on the BOM didn't scare anyone off, since they're a little on the high side. If you were on a tight budget, you could easily build up this PCB for less than $50 if you don't splurge on caps and resistors. The basic parts are quite cheap, and like I said, if you don't want to build the digital input section or PSU, then things get even cheaper.
I already offered qusp the option of chopping off the PSU part which is indicated by the line across the board just below the PSU output caps. If anyone else wants this done, I can use the shear we have at work to make a nice clean perfect cut, and then send out both parts of the board. You can use your own PSU that way, and use the cutoff portion for something else if need be.
As for output coupling caps, I think I'm going to leave them the way they are. If you want to use giant size polypropylene caps for the outputs, then it's quite easy to solder one end on the PCB and the other directly to the XLR output jacks. All you'd need is to mount the two 100K resistors on the outputs up to XLR connector instead of the PCB.
As for group buys, I'll probably offer up all the smaller and cheaper parts (everything SMD) as an option with the boards. I'm not going to handle any of the more expensive parts like the Caddock resistors or the Linear regulators. If people want to organize their own buys for that stuff, then that would be best.
Anyone interested in a group buy for the SMD parts on the boards, please let me know and I'll get some pricing together.
The boards are going out on Monday, and should be in the following Monday when I'll start sending them out. Any group buy parts will have to be ordered over next week.
Cheers,
Owen
Sorry for dropping this over the past week... it has been a busy one for me job-wise. I've got a pretty big career change on the go, so the next few weeks are going to be hectic.
Just the same, I'd like to get all these Gerbers sent out so that I can focus on other things while the boards are being made.
I've noticed a few people drop out of the board purchase, so I'm going to order 40 and call it at that. I'll see what the PCB fab can do for pricing with that number of boards.
I hope the prices on the BOM didn't scare anyone off, since they're a little on the high side. If you were on a tight budget, you could easily build up this PCB for less than $50 if you don't splurge on caps and resistors. The basic parts are quite cheap, and like I said, if you don't want to build the digital input section or PSU, then things get even cheaper.
I already offered qusp the option of chopping off the PSU part which is indicated by the line across the board just below the PSU output caps. If anyone else wants this done, I can use the shear we have at work to make a nice clean perfect cut, and then send out both parts of the board. You can use your own PSU that way, and use the cutoff portion for something else if need be.
As for output coupling caps, I think I'm going to leave them the way they are. If you want to use giant size polypropylene caps for the outputs, then it's quite easy to solder one end on the PCB and the other directly to the XLR output jacks. All you'd need is to mount the two 100K resistors on the outputs up to XLR connector instead of the PCB.
As for group buys, I'll probably offer up all the smaller and cheaper parts (everything SMD) as an option with the boards. I'm not going to handle any of the more expensive parts like the Caddock resistors or the Linear regulators. If people want to organize their own buys for that stuff, then that would be best.
Anyone interested in a group buy for the SMD parts on the boards, please let me know and I'll get some pricing together.
The boards are going out on Monday, and should be in the following Monday when I'll start sending them out. Any group buy parts will have to be ordered over next week.
Cheers,
Owen
Hi Guys,
Looks like there's definitely enough interest to make a group buy for the SMD parts worthwhile. I'll crunch the numbers and see what will be included and how much can be saved in the process. Then I can place a Digikey order and include the SMD parts when I ship out the boards.
I would consider soldering the SMD parts if people need this done, but it's the sort of thing that takes a while to do by hand, and would certainly come at a premium.
RichLund:
The transformer should be a dual 40VAC secondary, and should be rated for at least 25-30VA continuous. I was initially going to spec this:
Antek - AN-0240
but I think I'll be suggesting the larger 50VA version instead:
Antek - AN-0540
It's only $2 more ($13 instead of $11) and the 25VA is really pushing it. It would probably be fine with 60Hz, but not really for 50Hz. The above is assuming you're using two transformers, one per channel which is what I would suggest.
The power draw breaks down like this:
For +/- 45VDC rails (what I would strongly suggest) there will be 117mA of current per leg (and there are two legs per channel). So, that's 234mA total from 90VDC total, which is 21W per channel. There is also the power lost in the regulators, which in this case would be about 10V per reg, at 234mA for a total of 2.34W each. That means we're looking at a grand total of 25.7W constant power draw per channel.
Greg Stewart:
I have a rail of the FQA32N20's so if you're having a lot of trouble finding them, I can sell a few from my stash. I'm actually going to consider offering these matched for transconductance and VDS, but I'm not sure if I have a large enough number to get good matching. I'll see how things looks when I go to match my pairs.
Cheers,
Owen
Looks like there's definitely enough interest to make a group buy for the SMD parts worthwhile. I'll crunch the numbers and see what will be included and how much can be saved in the process. Then I can place a Digikey order and include the SMD parts when I ship out the boards.
I would consider soldering the SMD parts if people need this done, but it's the sort of thing that takes a while to do by hand, and would certainly come at a premium.
RichLund:
The transformer should be a dual 40VAC secondary, and should be rated for at least 25-30VA continuous. I was initially going to spec this:
Antek - AN-0240
but I think I'll be suggesting the larger 50VA version instead:
Antek - AN-0540
It's only $2 more ($13 instead of $11) and the 25VA is really pushing it. It would probably be fine with 60Hz, but not really for 50Hz. The above is assuming you're using two transformers, one per channel which is what I would suggest.
The power draw breaks down like this:
For +/- 45VDC rails (what I would strongly suggest) there will be 117mA of current per leg (and there are two legs per channel). So, that's 234mA total from 90VDC total, which is 21W per channel. There is also the power lost in the regulators, which in this case would be about 10V per reg, at 234mA for a total of 2.34W each. That means we're looking at a grand total of 25.7W constant power draw per channel.
Greg Stewart:
I have a rail of the FQA32N20's so if you're having a lot of trouble finding them, I can sell a few from my stash. I'm actually going to consider offering these matched for transconductance and VDS, but I'm not sure if I have a large enough number to get good matching. I'll see how things looks when I go to match my pairs.
Cheers,
Owen
wow i've been watching this thread all week with nothing and I turn my back for a moment and look what happens haha. right well sorry if I missed this info, but what was the price on the boards? just need to work out finances. its possible I will just go with 1 because I havent heard back from my friend since seeing its moving ahead. that may change by the time you make the order or receive them, but just trying to work out if I should just cover it for him. I would be keen on the SMD parts for the IV section only and could possibly organize the linear GB if others are keen, though I wont be using them here I would probably throw in to grab a few for other projects.
I bought a small rail of the fets, but I hadnt bothered before matching them, I would be interested in a circuit for a simple testing jig if you have that info owen, obviously I have a DMM.
haha the qusp mod coming together nicely to, because my PTFE/2 oz Cu/Ag/Au ackodac PCBs are going off to fab shortly
I bought a small rail of the fets, but I hadnt bothered before matching them, I would be interested in a circuit for a simple testing jig if you have that info owen, obviously I have a DMM.
haha the qusp mod
coming together nicely to, because my PTFE/2 oz Cu/Ag/Au ackodac PCBs are going off to fab shortly - Status
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