They sure are. Thanks for the link to them @namghiwook
With my M2X, which I'm still chasing down a tiny hum in one channel yet is otherwise GLORIOUS in sound (euphonic?), I did that blasphemous change of R6 and RV1, and yesterday spent 2 hours warming it up and setting the DC offset. Covers on, checking, tweaking, waiting, etc.)
That said, its DC offset floats a fair amount as close to centered around the 0mV (i.e. ~-20mV to +20mV) region as I can get it. Other amps I've built here have been much more solid on DC offset. That's life. +/- 20mV won't hurt anything.
But what a great sounding amplifier. Organic, soundstage, timbre, space. Just perfect for my home office about 12' x 14'.
I've ordered onsemi J113 20pcs in Mouser.
I'll try the matching method of Mark Johnson.
However 20pcs do not seem to be enough for matching 2 pairs.
Also I've ordered philips J113 4pcs.
https://www.ebay.com/itm/162192157881
I read this post #3702.
He said "Thoughts, the Phillips are all a lot closer overall.".
I hope my ordered philips j113s being closer enough.
I'll try the matching method of Mark Johnson.
However 20pcs do not seem to be enough for matching 2 pairs.
Also I've ordered philips J113 4pcs.
https://www.ebay.com/itm/162192157881
I read this post #3702.
He said "Thoughts, the Phillips are all a lot closer overall.".
I hope my ordered philips j113s being closer enough.
@Plott ,
there was a good article at heise.de why ALI not more will send to Austria: https://www.heise.de/news/Aliexpres...ckungsgesetz-auch-in-Deutschland-7454224.html
I bought 25 when I did a build that needed to match 4, and there wasn't a problem. I ended up with 2-quad matches, a good match and a decent quad matched all from the 25. You will be fine. I should note I used SMD version, so they were on a roll and so they were guaranteed to be the same manufacture batch.
Thank you for some cool information.
https://www.mouser.kr/ProductDetail/onsemi-Fairchild/MMBFJ113?qs=ljbEvF4DwOMU02MOFtlwqg==
Does packaging 'Cut Tap / MouseReel' guarantee the same batch? I did not know that.
https://www.mouser.kr/ProductDetail/onsemi-Fairchild/MMBFJ113?qs=ljbEvF4DwOMU02MOFtlwqg==
Does packaging 'Cut Tap / MouseReel' guarantee the same batch? I did not know that.
I find that putting an angle at the corner of the heatsink and bottom plate and one also on the top plate / heatsink adds a lot of rigidity. This way, you don't need to worry about the extra heat resistance between the spreader plate and heatsink.
The top angle also allows the top plate to sit flush with the top of the heatsink, which I prefer.
EDIT: this is in reply to post 6280. A bit behind here.
The top angle also allows the top plate to sit flush with the top of the heatsink, which I prefer.
EDIT: this is in reply to post 6280. A bit behind here.
Cut tape, highly likely, but not guaranteed to be from the same batch. If all the parts are sent to you on the same tape... yes... they'll be the same batch. However, you may get two or more pieces of cut tape depending on what they've got in inventory from other cuts and the quantity you need. Only ordering 20... you'll almost definitely get one tape of the same batch.
MouseReel, yes. You'll get all the parts (up to 3000) from the same reel. However, there is an extra fee. They also attach the leader, which you don't need.
With the quantity you want... and at the price of the added fee... you could order double the parts (40) cut tape and come out roughly the same.
I'd take your chances with cut tape...
my
from limited experience / DIY vs. manufacturing.@ItsAllInMyHead
Thank you for detail comment.
I've ordered J113 2 qty of 2 pieces in a cut tape.
I consider that J113 pair matching is only needed on each channel IPS6 board.
Then can I try using these pair as it is?
Thank you for detail comment.
I've ordered J113 2 qty of 2 pieces in a cut tape.
I consider that J113 pair matching is only needed on each channel IPS6 board.
Then can I try using these pair as it is?
^ I hope I didn't lead you down the wrong path... consecutive parts on the tape aren't guaranteed to be tight matches. You'd likely still need a reasonable population from which to sample. I hope 4 is enough, but it's doubtful. 40 consecutive parts from the same tape would likely be plenty to get you a few pair (based on Mark's experiment), and one person said they got some great matches out of a sampling of 25 SMD parts consecutively cut from the same reel.
I like the approach you had previously of asking around to see if someone has a few to spare they could offer. I'd gladly send you some if I had them.
I haven't yet built the IPS6 (bad me). There's no way to know if they'll 'work' until you get them and measure them.
I like the approach you had previously of asking around to see if someone has a few to spare they could offer. I'd gladly send you some if I had them.
I haven't yet built the IPS6 (bad me). There's no way to know if they'll 'work' until you get them and measure them.
Oh well... After turning on my M2x and just seconds after the protection circuit was on, there was a quiet static noise out of the left speaker and the protection switched the speakers off... 
So the search for the problem begins... soon, or later. I'm lazy because I'm tired 
Maybe it's just the DC offset... or something died. There was no smoke, not even heat (it can't be after seconds). Will see. Not a great start into the weekend
So the search for the problem begins... soon, or later. I'm lazy because I'm tired Maybe it's just the DC offset... or something died. There was no smoke, not even heat (it can't be after seconds). Will see. Not a great start into the weekend
Yeah, I see.
I try some known matching methods.
Thank you for your kindness again!
Hello!
I, a boob, managed to build this amp and am super pleased with the results. Many times during the process I was halfway through writing a post with a question when my imaginary Mark Johnson voice said, “You’ll be better off if you figure it out yourself.” Often I wondered, “Do I want to be better off or to have a sweet amp?”
Having constructed a WHAMMY and a couple of Elekits prior to this, I’ll say that the thinking to soldering ratio was WAY higher on this one — figuring out a power supply, making a dim bulb tester, debugging my mistakes — but it was a very gratifying process, and the end result is just wonderful.
Thanks to Mark Johnson and 6L6 in particular, but many, many of you nice folks posted insights that helped me find my way. Thank you all.
I, a boob, managed to build this amp and am super pleased with the results. Many times during the process I was halfway through writing a post with a question when my imaginary Mark Johnson voice said, “You’ll be better off if you figure it out yourself.” Often I wondered, “Do I want to be better off or to have a sweet amp?”
Having constructed a WHAMMY and a couple of Elekits prior to this, I’ll say that the thinking to soldering ratio was WAY higher on this one — figuring out a power supply, making a dim bulb tester, debugging my mistakes — but it was a very gratifying process, and the end result is just wonderful.
Thanks to Mark Johnson and 6L6 in particular, but many, many of you nice folks posted insights that helped me find my way. Thank you all.
Hi again,
it took some time to make the measurements and it's somewhat strange because the amp seems to be okay
I have +12,5 mV DC offset in the right channel and -26,8 mV in the left one. After turn on the values change between about -40 and +80 mV in both channels. The amp was on for some hours now and there was no turn off by the protection... The only thing I have noticed is the voltage change after turn off; the right channel went up to 34 mV, but the left channel (there was originally the problem with the static noise) up to 830 mV - but as I said, only after turn off. Can that still have a meaning?
Hints and ideas would be much appretiated or should I just use the amp and don't think about the issue?
Many thanks!
it took some time to make the measurements and it's somewhat strange because the amp seems to be okay
I have +12,5 mV DC offset in the right channel and -26,8 mV in the left one. After turn on the values change between about -40 and +80 mV in both channels. The amp was on for some hours now and there was no turn off by the protection... The only thing I have noticed is the voltage change after turn off; the right channel went up to 34 mV, but the left channel (there was originally the problem with the static noise) up to 830 mV - but as I said, only after turn off. Can that still have a meaning?
Hints and ideas would be much appretiated
or should I just use the amp and don't think about the issue?Many thanks!
