Wow, JT, a great review - thank you!
For me, many of your comments relate to the part of the topology of the amp, and it's helping me focus on what does what with amp design.
You have a beautiful case, are you perhaps a Fitter/Machinist? Your skill with metal puts you leagues above 99% of us, that's for sure.
I need to find out a bit about the J2. I have not seen that in detail yet, thanks for the tip!
HD
For me, many of your comments relate to the part of the topology of the amp, and it's helping me focus on what does what with amp design.
You have a beautiful case, are you perhaps a Fitter/Machinist? Your skill with metal puts you leagues above 99% of us, that's for sure.
I need to find out a bit about the J2. I have not seen that in detail yet, thanks for the tip!
HD
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J2 clone by Jeff Young has pair of 2Sk170 for CCS of the LTP and J109’s LTP input stage. Power n- JFET SE Class A output stage with optoisolator controlled bias for CCS.
https://www.diyaudio.com/forums/att...4-skinny-builders-thread-diy-j2-schematic-pdf
https://www.diyaudio.com/forums/att...4-skinny-builders-thread-diy-j2-schematic-pdf
Thanks everyone, and I hope the review is helps you Hugh.
The J2 and the the ANs for that matter were built to go into my dedicated room which has 8ohm speakers in it, so I will give them both some time in there. I will get back when I do some listening on the Horn1 8ohm.
I also have a M2X done and sitting here, but no case to put it in. MY amp building will be put on hold soon as the ice is about out here. I'm going to check the lake today, but I heard it's on the way out.
If anyone has specific questions, or would like some pictures of the guts, let me know.
Hugh, the metal work is more aesthetic and it might look like more was done that actually is. I do have access to a full machine shop and a friend who is an amazing machinist. I'm able to do simple stuff, but he has the real talent.
Thanks again everyone and esp Hugh, Jeff, JP and Pappa for your designs and Jim's always taking the time to help us newbs through the process. I know it;s has to be frustrating at times.
JT
Not having any luck trying to solder the SMD components on the Snubber boards.
I am using "Dispensing Grade Leaded Solder Paste Sn63 NC254" from a syringe. What I did was:
* extrude a small length of this paste onto the solder pads either side of where the SMD components goes
* hold it in place with the side of some needle-nosed tweezers
* then direct hot air onto the SMD component.
When Hugh showed me this process a couple of weeks ago (using the same paste), I could see that the grey stuff flowed everywhere when it was melted by the hot air ... but the actual solder in the paste remained on the pad and held the SMD component, when it cooled.
Whereas what is happening in my case is:
* the grey stuff flows everywhere when the hot air goes onto it
* but the SMD component does not stay fixed in place - so it appears there in no solder in the grey paste?
Any suggestions, guys? Vunce, I saw you had done some great SMD soldering in an earlier post!
Andy
I am using "Dispensing Grade Leaded Solder Paste Sn63 NC254" from a syringe. What I did was:
* extrude a small length of this paste onto the solder pads either side of where the SMD components goes
* hold it in place with the side of some needle-nosed tweezers
* then direct hot air onto the SMD component.
When Hugh showed me this process a couple of weeks ago (using the same paste), I could see that the grey stuff flowed everywhere when it was melted by the hot air ... but the actual solder in the paste remained on the pad and held the SMD component, when it cooled.
Whereas what is happening in my case is:
* the grey stuff flows everywhere when the hot air goes onto it
* but the SMD component does not stay fixed in place - so it appears there in no solder in the grey paste?
Any suggestions, guys? Vunce, I saw you had done some great SMD soldering in an earlier post!
Andy
Hi Andy,
Sorry to hear your having a bit of issues.
What really helps is to preheat the pcb with pasted components on a hot plate. When the board reaches about 135°C, hit the topside with your hot air pencil. The paste flows within 10 seconds. Use the slowest air speed to avoid blowing the components around.
Hope this helps
Sorry to hear your having a bit of issues.
What really helps is to preheat the pcb with pasted components on a hot plate. When the board reaches about 135°C, hit the topside with your hot air pencil. The paste flows within 10 seconds. Use the slowest air speed to avoid blowing the components around.
Hope this helps
The snubber boards are small and should easily work with just a hot air pencil. Use the lowest velocity setting, largest diameter nozzle and blow straight down while moving the pencil around in a pattern emulating shape of the board. It should not blow around. A hot plate helps a lot but not needed here.
Thanks, guys.
I'm doing what y'all suggest - with no issues! My problem is that what comes out of the solder paste syringe ... doesn't seem to contain any solder?? So the SMD component doesn't attach itself to the 2 solder pads.
So, at this stage, I will drop back to 'conventional' soldering (using solder) - using some excellent, detailed instructions which Gary had sent to me - and see how that goes.
I might also go out and buy a different syringe of 'air gun solder'.
Andy
I'm doing what y'all suggest - with no issues! My problem is that what comes out of the solder paste syringe ... doesn't seem to contain any solder?? So the SMD component doesn't attach itself to the 2 solder pads.
So, at this stage, I will drop back to 'conventional' soldering (using solder) - using some excellent, detailed instructions which Gary had sent to me - and see how that goes.
I might also go out and buy a different syringe of 'air gun solder'.
Andy
Hi zman,
I am using "Dispensing Grade Leaded Solder Paste Sn63 NC254" from a syringe.
Yes, I set the air temp to 350 deg C - this is shown on a digital readout.
As I said, the hot air melts the solder paste fine ... but when I scrape the surrounding puddles area clean ... the SMD component doesn't stay attached to the solder pads.
Andy
Sounds like bad solder paste that has separated from an emuslion of fine microscopic balls of solder and the liqiid flux. What you have coming out sounds like translucent liquid flux minus the solder microspheres. Can you post a photo of what the paste looks like when dispensed?
It should look like silver metal colored toothpaste.
Certainly does sound like that, X.
Pic attached - though not sure you can make anything out from it!
It occurred to me that I might've made the delivery hole too small, when I cut the tip off the syringe cap - and this small hole was filtering out the solder ... so only the paste passed through?
So, before taking the pic, I enlarged the hole - what has now come out is darker than it was before ... so maybe that was the trouble?
I'll try soldering again, later today, and see if there's now solder in with the flux.
This is the only URL I have, zman:
https://www.altronics.com.au/p/h1640-sn63-pb37-solder-paste-15g-syringe/
Regards,
Andy
Attachments
Well, the 100 ohm R1001 resistors on the 8x Snubber boards went pretty well, with Gary's excellent instructions for soldering conventionally.
Getting back to using solder paste, though:
* on the Snubber boards, there are 4x SMD components in close proximity.
* when using the hot air gun ... how do you stop the component you've just done from coming loose when you solder the adjacent component?
* surely, as you can't focus the hot air stream to the same degree you can a soldering iron tip, you will tend to melt the paste used to secure the previous item, when you solder the next one?
Andy
Getting back to using solder paste, though:
* on the Snubber boards, there are 4x SMD components in close proximity.
* when using the hot air gun ... how do you stop the component you've just done from coming loose when you solder the adjacent component?
* surely, as you can't focus the hot air stream to the same degree you can a soldering iron tip, you will tend to melt the paste used to secure the previous item, when you solder the next one?
Andy