Sole known exception from rule is our own Variac, and those are well known of having a fuse
In fact, I always got him as extra funny and loving guy, and those are usually not having a fuse
ZM in trilemma ...........
(for non-initiated ones, Variac's email addy was for eons iguana@something.something)
Hi Ben!
Great! I will send you a PM of my email address for the gerber files. In the meantime, for members who will read this post, if you have a pair of boards to spare, please let me know.
I have read a lot on and off regarding this thread . I will revisit the pages from #173 onwards. Thanks again!
I have a spare set of boards. PM me with your contact details if you are interested.
First unit with board connections complete. Powered up with No SIT attached. Used both Variac and DBT to power up. Power supply came up, LEDs lit up , no short or smoke.
Unless I'm mistaken, power supply ground is solely present on the board through the SIT. So not a lot should be happening at this point if all is well.
Second unit is next followed by building the dummy load.
An 8/4 ohm dummy load will be super useful going forward so I want to put some effort into the build. I may wander about Home Depot looking for a big piece of copper or aluminum used for another purpose (wish me luck). Maybe if the intended use is plumbing rather than Hi End Audio.....the price will drop significantly.
Unless I'm mistaken, power supply ground is solely present on the board through the SIT. So not a lot should be happening at this point if all is well.
Second unit is next followed by building the dummy load.
An 8/4 ohm dummy load will be super useful going forward so I want to put some effort into the build. I may wander about Home Depot looking for a big piece of copper or aluminum used for another purpose (wish me luck). Maybe if the intended use is plumbing rather than Hi End Audio.....the price will drop significantly.
Attachments
Not sure what you mean by that. There is a power supply Ground connection on the board next to the power supply V- connection. The SIT drain should be connected to the board at the SIT Drain connection point.
Did you test the power supply on its own before connecting the amplifier board to it?
I am again confused. What is this reference to "ground point at R1"?
But getting back to power-up. Did you power up and test in stages as I recommended in my building tips? That is, test the power supply alone first, and add stages after each successful test.
You mentioned that you used a Variac and dim bulb tester and that is good.
As for what to check for, the first important check would have been during the initial power up of the power supply to check the voltage and polarity. Make sure V- from the power supply is negative voltage. Next when you connect the power supply to the amplifier board, be sure that the polarity is correct. Be sure that V- is connected to V- on the amplifier board.
When powered up with no SIT, no current should flow. I did mentioned that in my Building Tips post.
But getting back to power-up. Did you power up and test in stages as I recommended in my building tips? That is, test the power supply alone first, and add stages after each successful test.
You mentioned that you used a Variac and dim bulb tester and that is good.
As for what to check for, the first important check would have been during the initial power up of the power supply to check the voltage and polarity. Make sure V- from the power supply is negative voltage. Next when you connect the power supply to the amplifier board, be sure that the polarity is correct. Be sure that V- is connected to V- on the amplifier board.
When powered up with no SIT, no current should flow. I did mentioned that in my Building Tips post.
I apologize for any confusion. Yes the supply was tested. Yes the polarity is correct.Yes I read your instruction. Yes I expected no current to flow in the .1ohm resistors as mentioned in your instructions.
Was only trying to state that with all the SIT connections open, not a great deal is happening (as expected). In looking over the schematic to see what to look for, ground appears at the: SIT Drain (open for test) / Speaker negative out (open no load attached) / Input negative ( open nothing attached ) / C2 (charges and blocks dc current so essentially open) . I missed the ground tie in at R1 so my initial statement was incorrect and why I tried to clarify with the R1 comment.
Appreciate all the help, sorry for the confusion, didn't intend to imply anything was amiss.
Will try to be more exacting in the future if I comment.
Was only trying to state that with all the SIT connections open, not a great deal is happening (as expected). In looking over the schematic to see what to look for, ground appears at the: SIT Drain (open for test) / Speaker negative out (open no load attached) / Input negative ( open nothing attached ) / C2 (charges and blocks dc current so essentially open) . I missed the ground tie in at R1 so my initial statement was incorrect and why I tried to clarify with the R1 comment.
Appreciate all the help, sorry for the confusion, didn't intend to imply anything was amiss.
Will try to be more exacting in the future if I comment.
I apologize if it seemed that I was picky and questioned the obvious. However, I was being careful and trying to be sure that I understood the situation. Long distance construction review and trouble shooting can be a challenge. Since the mosfet and SIT are pricey devices, I do not want to have any of them destroyed by a misunderstanding. So I was being extra careful. That is also the reason that I recommended stages of testing to minimize the possibility of damaging the devices.
Since this is a public DIY forum, I may repeat myself and restate the obvious to emphasize some things in the hope that other members who may be building this amplifier will benefit from my comments. My goal is to have everyone building this amplifier do so successfully with no need for troubleshooting.
Since this is a public DIY forum, I may repeat myself and restate the obvious to emphasize some things in the hope that other members who may be building this amplifier will benefit from my comments. My goal is to have everyone building this amplifier do so successfully with no need for troubleshooting.
After the Bills lost I decided to take a football break and run through the final stages on one channel.
I followed Ben's procedure closely and all went wonderfully.
Ran for 2hrs / heat was managed / CCS was rock solid at 2.5a / Power supply ended up around 65v / Only saw a .1v drift across the SIT source/drain over the 2hrs (could have just been my meter)
After 1hr, I decided to hook up a speaker and source via a BOZ preamp. No buzz , hum , or any noise was detected with my ear touching the speaker.
Music played nicely from the test set up. No thump occurred at power down.
I do have a scope but no spectral analyzing capabilities. May look later.
Not sure 2hrs was long enough a test and plan to probably double that time when I'm able. Will move on to the next channel and hope for similar results.
A huge Thank You to Mr. Pass and Ben for providing and enabling this project.
I followed Ben's procedure closely and all went wonderfully.
Ran for 2hrs / heat was managed / CCS was rock solid at 2.5a / Power supply ended up around 65v / Only saw a .1v drift across the SIT source/drain over the 2hrs (could have just been my meter)
After 1hr, I decided to hook up a speaker and source via a BOZ preamp. No buzz , hum , or any noise was detected with my ear touching the speaker.
Music played nicely from the test set up. No thump occurred at power down.
I do have a scope but no spectral analyzing capabilities. May look later.
Not sure 2hrs was long enough a test and plan to probably double that time when I'm able. Will move on to the next channel and hope for similar results.
A huge Thank You to Mr. Pass and Ben for providing and enabling this project.
