Today myself and @EUVL did a second beta test on the SMD FC CEN IV, testing each stage of the circuit section by section and everything checked out OK. This is good news as it verifies functionality and gives very good assurance that the built modules will function excellently. Everything seems completely stable, 2 hour stability test was as expected.
Photo attached of a 1khz sine wave and the subject of the experiment.....
Photo attached of a 1khz sine wave and the subject of the experiment.....
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Hey guys, quick update.
I managed to solder 13 pairs so far. First 10 pairs will be on the way to Fran for testing and final assembly this week. And I plan to finish the rest by the end of the week, and send them to Patrick next week...
Uros
I managed to solder 13 pairs so far. First 10 pairs will be on the way to Fran for testing and final assembly this week. And I plan to finish the rest by the end of the week, and send them to Patrick next week...
Uros
20 units are now in Ireland with Fran, the other 20 on their way to me, i.e not arrived yet.
That was how long Ripster needed to solder part of the components to reduce our work load.
Fran tested the first unit, and both MOSFETs were defect, most probably due to electrostatics during handling.
One of them is NOT in stock at Mouser till mid-June, so we have to wait before we can buy new, match, and replace.
Both of us have full time job and a bit of private life as well, so we cannot be doing this 8 hours a day.
We shall finish all 40 units first before shipping out.
How long it tales depends on how many of those MOSFETs are damaged, and when available.
As mentioned before, you can contact Ripster for a refund if you do not want to wait.
I was told that there is already a queue of stand-by buyers waiting for people to opt out.
We also want it out of the way, but it is what it is.
We'll try our best to get it delivered asap.
AND it will NOT happen again, because this will be the last GB for any of these as "Kits".
Apologies,
Patrick
That was how long Ripster needed to solder part of the components to reduce our work load.
Fran tested the first unit, and both MOSFETs were defect, most probably due to electrostatics during handling.
One of them is NOT in stock at Mouser till mid-June, so we have to wait before we can buy new, match, and replace.
Both of us have full time job and a bit of private life as well, so we cannot be doing this 8 hours a day.
We shall finish all 40 units first before shipping out.
How long it tales depends on how many of those MOSFETs are damaged, and when available.
As mentioned before, you can contact Ripster for a refund if you do not want to wait.
I was told that there is already a queue of stand-by buyers waiting for people to opt out.
We also want it out of the way, but it is what it is.
We'll try our best to get it delivered asap.
AND it will NOT happen again, because this will be the last GB for any of these as "Kits".
Apologies,
Patrick
Dear Patrick, there is no need for an apology! You, Fran and Ripster are doing a fantastic job. As you say, if someone wants to opt out it is possible. For the rest of us, we just sit tight and wait, because it will be worth it
/Anders
/Anders
Thank you for your support.
Good to know our work is appreciated.
Patrick
Good to know our work is appreciated.
Patrick
A short update from me.
I have now finish tested and built 10 of the 20 units sent to me.
3 units needed MOSFETs replaced; another had a defective resistor.
They are now all finished except for DC trimming.
Without trimming, DC offset is 40~60mV, very consistent.
AC tests behaved as intended.
So no design fault, and all (unobtanium) JFETs worked perfectly.
The only defects were damaged MOSFET gates, most likely due to electrostatics during handling.
Each unit took me 1.5~2 hours to build and test.
This is longer than normal as we have to build in small steps in order to locate defective parts, before they can damage the rest of the circuit.
I shall finish the remaining 10, trim DC for all, and then send to Fran for burn-in tests.
He has similar progress, but it will still take a few more weeks to finish the rest.
Then all 40 units will be sent back to Ripster for distribution, as per original GB.
Patrick
I have now finish tested and built 10 of the 20 units sent to me.
3 units needed MOSFETs replaced; another had a defective resistor.
They are now all finished except for DC trimming.
Without trimming, DC offset is 40~60mV, very consistent.
AC tests behaved as intended.
So no design fault, and all (unobtanium) JFETs worked perfectly.
The only defects were damaged MOSFET gates, most likely due to electrostatics during handling.
Each unit took me 1.5~2 hours to build and test.
This is longer than normal as we have to build in small steps in order to locate defective parts, before they can damage the rest of the circuit.
I shall finish the remaining 10, trim DC for all, and then send to Fran for burn-in tests.
He has similar progress, but it will still take a few more weeks to finish the rest.
Then all 40 units will be sent back to Ripster for distribution, as per original GB.
Patrick
And a short update from me - I have been making good progress, and have all 20 built and initial tests done. The job currently underway is to trim DC on each one, and mount on sockets. Patrick is faster than I am - he says its 1.5-2 hrs for each unit - I think I am slower than him!
The good news is that we are getting closer now to the very final stages, I can tell you all you are in for a treat with these.
The good news is that we are getting closer now to the very final stages, I can tell you all you are in for a treat with these.
The 20 units allocated to me have now also been full yfinished and trimmed for DC < 5mV.
Any tighter trimming can only be done with final power supply and in the final enclosure (thermal drift).
These 20 units now will be sent to Fran for soak-test, together with the others.
Then they will go back to Ripster for him to distribute.
My tasks have all been completed,
Patrick
Any tighter trimming can only be done with final power supply and in the final enclosure (thermal drift).
These 20 units now will be sent to Fran for soak-test, together with the others.
Then they will go back to Ripster for him to distribute.
My tasks have all been completed,
Patrick
Another update - all assembled, tested and soak tested modules are on the way to Ripster.... so this moves on now to the next stage.
fran
fran
Just received confirmation that the modules + unused spare parts are now with Ripster.
So both Fran and I have fulfilled all our obligations.
The only additional costs incurred by us are new opamps (mentioned before), some spare MOSFETs to replace defect ones,
consumables (PCB cleaner, etc.) and postage.
That is all.
Patrick
So both Fran and I have fulfilled all our obligations.
The only additional costs incurred by us are new opamps (mentioned before), some spare MOSFETs to replace defect ones,
consumables (PCB cleaner, etc.) and postage.
That is all.
Patrick
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Important Note for all group buy participants:
The power supplies you choose for this and how they are implemented is really important.
The units are all built for a bipolar 15V supply and each unit draws 15-16mA from each rail. Any change from 15V will mean the DC offset also changes. You can trim for this, but it is easier to set at 15V and leave them.
It is also critically important that the rails come up at the same time - ie one rail does not lag well behind the other. Check this with your scope if you are in doubt.
Also, do not be tempted to put a switch between whatever regulator you choose and the IV module - the switch arcing in any way will take out the opamp on the circuit. Don't ask how I know this!
Lastly, I have used LT3045/3094 supplies almost exclusively in powering these and these have performed excellently throughout.
Happy building to all, and I hope you all enjoy them, they are really excellent sounding IV units, and it is well worth your while putting this last bit of money and effort into them!
The power supplies you choose for this and how they are implemented is really important.
The units are all built for a bipolar 15V supply and each unit draws 15-16mA from each rail. Any change from 15V will mean the DC offset also changes. You can trim for this, but it is easier to set at 15V and leave them.
It is also critically important that the rails come up at the same time - ie one rail does not lag well behind the other. Check this with your scope if you are in doubt.
Also, do not be tempted to put a switch between whatever regulator you choose and the IV module - the switch arcing in any way will take out the opamp on the circuit. Don't ask how I know this!
Lastly, I have used LT3045/3094 supplies almost exclusively in powering these and these have performed excellently throughout.
Happy building to all, and I hope you all enjoy them, they are really excellent sounding IV units, and it is well worth your while putting this last bit of money and effort into them!
Hey guys, finally at the finish line, I am on vacation till the end of the week so I will start to package and send packets out next week... So before I start shipping If anyone moved to a different address during this GB now will be the time to inform me of any change.
Hey, I managed to pack everything and I created shipping labels. So I hope I will send everything out on Friday or Saturday.
And thank you all for your patience...
And thank you all for your patience...