Here tis-
L- 69.3v at PS, 7.52v at PVI, 23.95 at the resistor, DC OS- 0.0002v
R- 69.2v at PS, 7.47v at PVI, 23.95 at the resistor, DC OS- 0.299v
Couldn't get a solid measurement across the LED pins on either board. The R seemed to be making good contact but would not settle down.
Not sure why the regulator on the R is getting hotter (140 vs 98F). I'll reseat the heat sink.
JG
L- 69.3v at PS, 7.52v at PVI, 23.95 at the resistor, DC OS- 0.0002v
R- 69.2v at PS, 7.47v at PVI, 23.95 at the resistor, DC OS- 0.299v
Couldn't get a solid measurement across the LED pins on either board. The R seemed to be making good contact but would not settle down.
Not sure why the regulator on the R is getting hotter (140 vs 98F). I'll reseat the heat sink.
JG
Last edited:
Any hot caps on either regulator board?
Carefully look for any burnt traces as well please.
Carefully look for any burnt traces as well please.
Last edited:
If you touch the input wires/connections on RCA, do you get AC on output? (hum)
As for offset, measure voltage to ground after the input cap, at pins 2 and 3 of first chip, and at the top ends of the 3,3k resistors above the dc trim pot.
As for offset, measure voltage to ground after the input cap, at pins 2 and 3 of first chip, and at the top ends of the 3,3k resistors above the dc trim pot.
Last edited:
Reworked the light board and things are looking mostly better. While reworking he lightboard i also changed the amp chips, transistors and most of the smaller caps (not the aluminum ones).
Both channels are functioning. The light board regulator on L channel is about (130 F). Confirmed the heat diffuser was not resting on the light contacts. There also continues to be about .295 v at the speaker output on the L. The Right terminals are at 0.0001v. I measured DC offset after the input capacitor and it is 0002v. The three resistors next to the diode that I initially omitted are also warmer than the other channel (124 F vs 85 F) There are 2 little caps (can't remember value)next to the diode and 3 resistors. The one closer to the resistors is also warmer. I have the resistors and can swap those I don't have a spare cap. This was not one of the caps I changed (it was backordered. argh!). Should have ordered a similar product but NO!
Thanks Jeremy for your above and beyond assistance. Getting closer.
Both channels are functioning. The light board regulator on L channel is about (130 F). Confirmed the heat diffuser was not resting on the light contacts. There also continues to be about .295 v at the speaker output on the L. The Right terminals are at 0.0001v. I measured DC offset after the input capacitor and it is 0002v. The three resistors next to the diode that I initially omitted are also warmer than the other channel (124 F vs 85 F) There are 2 little caps (can't remember value)next to the diode and 3 resistors. The one closer to the resistors is also warmer. I have the resistors and can swap those I don't have a spare cap. This was not one of the caps I changed (it was backordered. argh!). Should have ordered a similar product but NO!
Thanks Jeremy for your above and beyond assistance. Getting closer.
My primary thought is checking resistor values because if you're using RN dales they are easier to mix up than other types.
You got the extra PVI board, right?
You got the extra PVI board, right?
Hey guys, just wanted to see if anyone else has not received the boards?
I am in Austria so maybe it takes a bit longer but they were shipped a while ago or?
Im itching to get started with this build!😀
Thanks!
I am in Austria so maybe it takes a bit longer but they were shipped a while ago or?
Im itching to get started with this build!😀
Thanks!
Yes, I got the board. Big thanks to you.
I replaced those resistors and one of the caps. Had some 10 Ohm (?) caps from the other board and measured them to see if they were in spec. Seemed to be. The resistors I changed are now running cooler. The regulator is not (130-140 F). Was fastidious (for me) to confirm the values of the 3 resistors. The two larger Dale resistors next to the larger (green on my board) cap are running warm (next to the ceramic cap). Might change those as well. The amp is running in now.
DC offset is still goofy. More likely, my measurement of the offset is goofy. Thought i had one board on target but it is now off. I am measuring at the side of the input cap near the PVI test points, right. negative to ground. The goofy board is still 0.295v. perhaps the potentiometer if fried? I have one of those as well.
I replaced those resistors and one of the caps. Had some 10 Ohm (?) caps from the other board and measured them to see if they were in spec. Seemed to be. The resistors I changed are now running cooler. The regulator is not (130-140 F). Was fastidious (for me) to confirm the values of the 3 resistors. The two larger Dale resistors next to the larger (green on my board) cap are running warm (next to the ceramic cap). Might change those as well. The amp is running in now.
DC offset is still goofy. More likely, my measurement of the offset is goofy. Thought i had one board on target but it is now off. I am measuring at the side of the input cap near the PVI test points, right. negative to ground. The goofy board is still 0.295v. perhaps the potentiometer if fried? I have one of those as well.
Let the amp cook today. Temps seemed to regulate through the day. pretty even now. I don't have offset dialed in well. Measuring at the input cap and ground, both sides are right about 0.019 or so. the potentiometers don't seem to do much.
After cooking for a few hours a put it in charge of magnepan 1.7is. Was expecting it to be a letdown after using the Class D Audio 125/250 wpc amp. Wow, was I mistaken. It is so much fun to listen to. So detailed and easy. The bottom is nice. imagine is fabulous. Volume is certainly plenty. i was anticipating buying a new amp for the newly acquired Maggies. maybe I'll just chill a bit. my Pass F6 was not a good match for the Maggie. This is different. The chips were about 110 F or so after 1.5 hours of listening at moderate volumes. Top was off but that can't reman off.
Jeremy, Where do i measure offset at the resisitors? I will try that. Also, i am using a 5A fast blow fuse at the AC input. That would be better as a slow blow, right. Is 5 A too high?
The amp sounds great!
After cooking for a few hours a put it in charge of magnepan 1.7is. Was expecting it to be a letdown after using the Class D Audio 125/250 wpc amp. Wow, was I mistaken. It is so much fun to listen to. So detailed and easy. The bottom is nice. imagine is fabulous. Volume is certainly plenty. i was anticipating buying a new amp for the newly acquired Maggies. maybe I'll just chill a bit. my Pass F6 was not a good match for the Maggie. This is different. The chips were about 110 F or so after 1.5 hours of listening at moderate volumes. Top was off but that can't reman off.
Jeremy, Where do i measure offset at the resisitors? I will try that. Also, i am using a 5A fast blow fuse at the AC input. That would be better as a slow blow, right. Is 5 A too high?
The amp sounds great!
What is the DC at output (binding posts)? I want to make sure you don't damage anything.
I'm glad you like the sound!
A 3A slow blow would be a good fuse. Think about 120w + 120w is 240w, divided by 120v is 2A. The only reason to go up in fuse size is if turn on pops it.
I'm glad you like the sound!
A 3A slow blow would be a good fuse. Think about 120w + 120w is 240w, divided by 120v is 2A. The only reason to go up in fuse size is if turn on pops it.
DC at the binding posts is attaching MM probes to speaker outputs and checking DC offfset there. Based on your response, this may be a learning moment for me.
I used a 2A fast blow (lowes) and they popped at turn on. I'll get a 3A slow blow.
I used a 2A fast blow (lowes) and they popped at turn on. I'll get a 3A slow blow.
Yes check at speaker output for DC.
A lot of things can be trimmed for DC more accurately at the start of circuit but in this case at speaker outputs is a good place.
A lot of things can be trimmed for DC more accurately at the start of circuit but in this case at speaker outputs is a good place.
Speak of PCBs and they shall appear!!😀
They were in the postbox this morning!
I am in the process of ordering the parts list as I type.
Jeremy, thanks again for doing another groupbuy, this looks like one fantastic amp and I appricieate your efforts in sharing this design with the community!
-Mac
They were in the postbox this morning!
I am in the process of ordering the parts list as I type.
Jeremy, thanks again for doing another groupbuy, this looks like one fantastic amp and I appricieate your efforts in sharing this design with the community!
-Mac
Just a few quick questions....
I usually dont use terminal blocks as I prefer to directly solder all of the board connections. Is there any negatives associated with not using the terminal blocks?
Once everything is built I dont plan on disconnecting anything again...
Also wanted to ask if it is important to match the 4 transistors for the error correcting circuit?
Thanks in advance!
I usually dont use terminal blocks as I prefer to directly solder all of the board connections. Is there any negatives associated with not using the terminal blocks?
Once everything is built I dont plan on disconnecting anything again...
Also wanted to ask if it is important to match the 4 transistors for the error correcting circuit?
Thanks in advance!
It also seems that these electrolytic caps are backordered for 31 weeks!😱
Mouser-Teilenr. :661-EGVD500E202MM30H
They are the 50V 2000uF caps that are on the main board. Is it ok to use any other electro caps with the same specs?
I found these as an alternative - Mouser-Nr.:661-EGXF630ELL202MM3
They are 63v. instead of 50v. and they are from United Chemi-con.
Would these be a suitable replacement?
Thanks again!
Mouser-Teilenr. :661-EGVD500E202MM30H
They are the 50V 2000uF caps that are on the main board. Is it ok to use any other electro caps with the same specs?
I found these as an alternative - Mouser-Nr.:661-EGXF630ELL202MM3
They are 63v. instead of 50v. and they are from United Chemi-con.
Would these be a suitable replacement?
Thanks again!
Anything with the same voltage and diameter will work. If you can use a similar capacitance or higher.
You can also check Digikey.
You can also check Digikey.