@Craigl59 Photo No. 2: Verify the values of R12, R11. I (maybe wrongly) read 183kR or 18k3R on R11
Craig,
Just trying to think, is the hold button switched on in your multimeter making you see 221 both the times? I am just trying to rule out this since like you said, pin 2 to R12 should be 321. Please cross check this once.
Just trying to think, is the hold button switched on in your multimeter making you see 221 both the times? I am just trying to rule out this since like you said, pin 2 to R12 should be 321. Please cross check this once.
It can be, you just haven't figured out why yet.
What do you get from pin 1 to pin 2 of Q5? Should be 421R. If you're taking any of these measurements with parts removed, please let us know.
This is confusing to me "But R12 in to R11 out being 221 ohms when it should be 321 is the issue and, as a direct line (with Q7 removed) then it must be additive"
Just so I understand, when you reference "in and out" when talking about resistors, what do you mean? As an example, where is "R11 in"? It is much easier to pinpoint where you're measuring by either describing it by the placement on the board itself or the junction on the schematic. Is "R11 in" equivalent to pin 2 Q5 or the Anode side of Q7/R11 junction?
Is it the lead closest to the silkscreen or the other lead?
Just examples. It is tough for me to determine precisely what/where you're measuring.
Either way, if you are measuring (with Q7 removed) for resistance and have both probes on the legs closest to the silkscreens for R11 and R12 (R11 pin 2 Q5 junction and R12/R14 junction) then you should definitely get 321R.
I think I am following you, but something (clearly as you've noted) is squirrely. If I'm not measuring in the precise spots you are, then we'll be going nowhere.
With Q7 out, you can test one theory of the board being at issue by checking continuity between all 3 pads for Q7.
You'll get this.
What do you get from pin 1 to pin 2 of Q5? Should be 421R. If you're taking any of these measurements with parts removed, please let us know.
This is confusing to me "But R12 in to R11 out being 221 ohms when it should be 321 is the issue and, as a direct line (with Q7 removed) then it must be additive"
Just so I understand, when you reference "in and out" when talking about resistors, what do you mean? As an example, where is "R11 in"? It is much easier to pinpoint where you're measuring by either describing it by the placement on the board itself or the junction on the schematic. Is "R11 in" equivalent to pin 2 Q5 or the Anode side of Q7/R11 junction?
Is it the lead closest to the silkscreen or the other lead?
Just examples. It is tough for me to determine precisely what/where you're measuring.
Either way, if you are measuring (with Q7 removed) for resistance and have both probes on the legs closest to the silkscreens for R11 and R12 (R11 pin 2 Q5 junction and R12/R14 junction) then you should definitely get 321R.
I think I am following you, but something (clearly as you've noted) is squirrely. If I'm not measuring in the precise spots you are, then we'll be going nowhere.
With Q7 out, you can test one theory of the board being at issue by checking continuity between all 3 pads for Q7.
You'll get this.
Those are not the resistor values. However, it would be nice if the resistor values were facing up for quick visual verification.
The value of the resistor (DALE) is in the line below 'RN60'. 1000F stands for the value of 100 ohms and 2210F for 221 ohms. The letter at the end describes the tolerance (F -> 1%).
On the third board (far right) there is no 'RN60' for R10 installed.
Please check again with your eyes.
On the third board (far right) there is no 'RN60' for R10 installed.
Please check again with your eyes.
Speaking about something else, I finally completed the Cedarburg and listened to it...the verdict: unlistenable to my ears.
The low frequencies are very punchy and precise but from there up the music is gone. By far the worst card I have tried. I don't quite get how it can be so bad I am wondering if there is something wrong with these cards.
The low frequencies are very punchy and precise but from there up the music is gone. By far the worst card I have tried. I don't quite get how it can be so bad I am wondering if there is something wrong with these cards.
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Oh man... it's all so subjective... but Cedarburg is our favorite here—taking out Norwood from the pedestal (honestly they are both so good)—we evaluated all the stages over about a year. MJ did say to my noob ears one time that component values are critical on that board—but I could have misunderstood too. Pretty sure 6L6 also told me that Cedarburg is like driving an F15 on the highway. Which is a visual I love—I could have gotten both of these points wrong. LOL. I'm sure I'll be corrected if so! (vinyl-centric system, but plenty of hi-res audio from the DAC too)
Not so much though. ;-) I have had people over for the comparison, and we were all looking at each other with the 'what just happened here' look on the face.
I am putting it up against the Vfet, the most musical amp I have ever tried on the altec 511/802 + 416. Remastered stuff from the 70s sounds amazing. All of that gone with the cedarburg.
IPS7 with LME49720 remains my favorite, you can listen to it for a while and not rush to put the Vfet back on.
I am putting it up against the Vfet, the most musical amp I have ever tried on the altec 511/802 + 416. Remastered stuff from the 70s sounds amazing. All of that gone with the cedarburg.
IPS7 with LME49720 remains my favorite, you can listen to it for a while and not rush to put the Vfet back on.
WKCox: Most generous offer. Am having roof and gutter work done this week and cannot accept visitors. Will contact you in 10 days if the problems are still here.
More confusing News.
Measured the path described above R12 in to R11 out on the working, right board and expected it to be 321 ohms. INSTEAD, it is the same 220 ohms as the non-working boards. But the working board still reads 321 ohms from R14 to Pin 2, Opto.
SO the resistors are NOT additive as I had presumed above (and was suggested as well by another above). Am now going to prepare a comparison of the working board with the non-working ones for the specific parameters listed in ItsAllInMyHead post above -- thanks, as always, IAIMH. Will post results shortly.
Measured the path described above R12 in to R11 out on the working, right board and expected it to be 321 ohms. INSTEAD, it is the same 220 ohms as the non-working boards. But the working board still reads 321 ohms from R14 to Pin 2, Opto.
SO the resistors are NOT additive as I had presumed above (and was suggested as well by another above). Am now going to prepare a comparison of the working board with the non-working ones for the specific parameters listed in ItsAllInMyHead post above -- thanks, as always, IAIMH. Will post results shortly.
I think it's very likely that member grataku assembled both Cedarburg boards correctly, with correct value components and brand new, non-counterfeit, correctly functioning AD797 chips purchased from a fist-tier electronics distributor. In which case, the boards are working exactly as designed, but the listening experience they provide is (strongly) not-preferred.
Way back in this thread, thousands of posts ago, another member posted that Norwood was powerfully suckful; unbearable and un-listenable. Just like all the other audio circuits he had ever built and listened to, using the 110 MHz Harris/Intersil/Renesas HA5002 video cable driver chip. He had convinced himself that the presence of an HA5002 in an audio signal chain, guarantees bad sound. Yet quite a few other M2x builders truly love Norwood and the sound it makes (including @pfarrell).
What does it mean? I think it means: Good thing there are so many M2x input stage daughter cards to choose from. If you don't like A, you have the option to try B (and C, and D, ...). Find one that you like. Possibly even find the one that you like best. Then don't get too concerned if other people like something else.
Baskin Robbins sells 31 flavors and I'm allowed to prefer Jamoca Almond Fudge while you favor Mint Chocolate Chip. It's all good.
Way back in this thread, thousands of posts ago, another member posted that Norwood was powerfully suckful; unbearable and un-listenable. Just like all the other audio circuits he had ever built and listened to, using the 110 MHz Harris/Intersil/Renesas HA5002 video cable driver chip. He had convinced himself that the presence of an HA5002 in an audio signal chain, guarantees bad sound. Yet quite a few other M2x builders truly love Norwood and the sound it makes (including @pfarrell).
What does it mean? I think it means: Good thing there are so many M2x input stage daughter cards to choose from. If you don't like A, you have the option to try B (and C, and D, ...). Find one that you like. Possibly even find the one that you like best. Then don't get too concerned if other people like something else.
Baskin Robbins sells 31 flavors and I'm allowed to prefer Jamoca Almond Fudge while you favor Mint Chocolate Chip. It's all good.
@grataku: I have compared Cedarburg and Vfet (I had 6L6's here for taking pics).... Both exceptional—I didn't do a super critical examination but we had it on for a couple of weeks and everyone here loved it—going back to M2X/Cedarburg definitely wasn't super massively different (they are different though)—but my M2X are mono blocks and I think that does something in our space to our ears, soundstage blah blah...musicality was 100% there in both amps... I'm building Vfet now.... as monos... Vfet was absolutely silent in our speaks—M2X has the faintest something when the ear is right on the tweeter. IDK... I find that evals of this stuff, I don't really know how I feel until I spend time with the new thing (a week plus)—and then go back to the "old" thing... then I feel I know "something"... not questioning what you are saying at all... maybe go over the boards with a fine tooth comb? Ha. Another thought: Speaker synergy? You have some insanely awesome speakers, I have never heard them however. These are mine: OSMC
Crosspost with Mark! He knows!!!! Another reason to celebrate all our differences...I do think the whole system and all components and the room are a balancing act... I wish we could all travel around and listen to all the amazing systems that people here have created. That would be insanely educational and fun.
Crosspost with Mark! He knows!!!! Another reason to celebrate all our differences...I do think the whole system and all components and the room are a balancing act... I wish we could all travel around and listen to all the amazing systems that people here have created. That would be insanely educational and fun.
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ItsAllinMyHead: Thanks for your post above; didn't quite get it all the first time but have now made the checks and can report the differences: they are substantial.
Pi 1 Q7 to Pin3 Q7 = OL on all boards
Pin1 Q7 to Pin2 Q7 = 100 ohms on all boards
Pin 1 Q7 to Pin 1 Q5 should be 200 ohms. On working board it is 100; on non-working it is 101
Pin 1 Q7 to Pin 2 Q5 should be 221 ohms. On working board it is 323; non-working is 221
Pin 2 Q7 to Pin 1 Q5 should be 100 ohms. On working board it is 201; non-working is 202
Pin 2 Q7 to Pin 2 Q5 should be 321 ohms. On working board it is 222; on non-working it is 220
R14 to Pin 1 Q5 should be 10 ohms; all boards read 101 ohms
R14 to Pin 2 Q5 should be 320 ohms; working board is 322, non-working is 221
R14 to Pin 1 Q7 should be 100 ohms; working and non-working are 0 ohms
R14 to Pin 2 Q7 should be 0 ohms; working and non-working boards are 100 ohms
Do these differences suggest that Q7 is mounted upside down? Of course, the orientation shown on the board itself is what has been followed.
Thanks again, IAIMH. There is something clearly amiss here.
Pi 1 Q7 to Pin3 Q7 = OL on all boards
Pin1 Q7 to Pin2 Q7 = 100 ohms on all boards
Pin 1 Q7 to Pin 1 Q5 should be 200 ohms. On working board it is 100; on non-working it is 101
Pin 1 Q7 to Pin 2 Q5 should be 221 ohms. On working board it is 323; non-working is 221
Pin 2 Q7 to Pin 1 Q5 should be 100 ohms. On working board it is 201; non-working is 202
Pin 2 Q7 to Pin 2 Q5 should be 321 ohms. On working board it is 222; on non-working it is 220
R14 to Pin 1 Q5 should be 10 ohms; all boards read 101 ohms
R14 to Pin 2 Q5 should be 320 ohms; working board is 322, non-working is 221
R14 to Pin 1 Q7 should be 100 ohms; working and non-working are 0 ohms
R14 to Pin 2 Q7 should be 0 ohms; working and non-working boards are 100 ohms
Do these differences suggest that Q7 is mounted upside down? Of course, the orientation shown on the board itself is what has been followed.
Thanks again, IAIMH. There is something clearly amiss here.
As other have mentioned it is difficult to measure resistances on board due to different possible current paths. Could you reverse your leads on your MM and check if you get the same resistance in the area of question. Wonder if you are forward biasing the optocoupler led and measuring a different current path.
My recommendation for resistor string measurements:
Take out Q6, Q7, Q5.
Measure resistor strings following traces on board. Always compare to schematic at every measurement.
Also, you might have confused Pins 1, 2, 3 on Q6 and Q7. Pin2 is always the middle pin on LM385. In your nomenclature, Pin1 would be that outer pin that has a trace connected to it, Pin3 without trace attached. (Schematic shows it the other way around, but that doesn't matter if you follow traces and remember that Pin2 is the middle pin.)
Before you put in 4N35 again, solder a socket at its position so that it is easier to remove or exchange in the course of further troubleshooting.
Regards, Claas
Take out Q6, Q7, Q5.
Measure resistor strings following traces on board. Always compare to schematic at every measurement.
Also, you might have confused Pins 1, 2, 3 on Q6 and Q7. Pin2 is always the middle pin on LM385. In your nomenclature, Pin1 would be that outer pin that has a trace connected to it, Pin3 without trace attached. (Schematic shows it the other way around, but that doesn't matter if you follow traces and remember that Pin2 is the middle pin.)
Before you put in 4N35 again, solder a socket at its position so that it is easier to remove or exchange in the course of further troubleshooting.
Regards, Claas
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I do not have a built and working MX2 but I have the boards. They seem to be the same revision as marked on your boards. And like your boards they are marked channel A and Channel B. It may be more helpful if you refer to the boards as they are marked not left or right.
However, testing my boards Q6 pin 1 (left pin or top pin) is not connect to anything else on the board. Q7 pin 1 (left pin) is also not connected to anything else on the board.
Opps Chede beat me to it.
However, testing my boards Q6 pin 1 (left pin or top pin) is not connect to anything else on the board. Q7 pin 1 (left pin) is also not connected to anything else on the board.
Opps Chede beat me to it.
jcon: reversed the leads on each measurement and they are all the same as reported in post 5573 above. Thanks for your response.
Claas: On my 385s and on the schematic, the middle pin is #1 and the right pin while facing is #2. #3 is the left side and it is always dead. So the order as shown on the schematic is 3-1-2. This is what gives me results while testing.
What is a resistor string measurement?
Claas: On my 385s and on the schematic, the middle pin is #1 and the right pin while facing is #2. #3 is the left side and it is always dead. So the order as shown on the schematic is 3-1-2. This is what gives me results while testing.
What is a resistor string measurement?
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Great. Doesn't tell us too much other than traces around R12 / Q7 / R14 are likely OK. You can see on the schematic that you're basically just measuring R12 + R14. However, look at your boards (assuming no current through Q7) and see the path that it has to take to measure around that loop. 🙂 That's one of reasons I asked for such a simple measurement. You're speculating that one issue could be with the boards, so, why not check a few easy things while you go?
So, how could both your working and non-working boards be the same, and both have a different than expected resistance measurement? I'd focus on fixing one at a time.
First... as silly as it sounds. Always triple check measurements for anything with multiple pins, particularly when one pin over gets you the correct measurement on at least one of the boards. Once you're confident that your measurements are accurate and repeatable...
Check the possible current pathways between those two points using the schematic. Note on the schematic that (if you're using the same parts as I) pins 1 and 3 are reversed. We cannot assume parts are behaving as they should. Assume when I say pin X I mean measure from the point on the board where pin X should be. Pin 1 is Anode, Pin 2 is Cathode. IMPORTANT TO LET US KNOW IF THAT IS NOT THE CASE.
Are you using the same part for Q6?? Same batch, packet, order? Let's do a bit more.
What would things look like if Q6 was a dead short between pins 1 and 2?
That might give us 100R (Q7,1 to Q5,1) and 221R (Q7,1, to Q5,2) if we're effectively circumventing R10.
Measure the resistance between actual Pin 1 (Anode) of Q7 to actual pin 2 of Q6 (Cathode). Do not measure their circuit equivalents on the board. One probe on what should be the right-most leg of Q7 and the middle leg of Q6 if the silkscreen lettering is right-side up.
Measure the resistance between Pins 1 and 2 of Q6.
Note - there are others that are FAR more experienced at this than I. I am chiming in b/c we are both relatively new to this (I think), and I might be able to walk you through it with a bit of thought re: how I think about it.
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chede: the sockets ordered don't come in until Thursday but at that time will try out several 4N35s ordered and see if there is a difference.
Am confused about your 385 pin description. The schematic seems wrong in that my middle pin is shown as inactive while the left side pin is always dead on my 385s. Am using the convention of facing meaning looking at the flat side of the 385. This way, the order is 3-1-2.
Am confused about your 385 pin description. The schematic seems wrong in that my middle pin is shown as inactive while the left side pin is always dead on my 385s. Am using the convention of facing meaning looking at the flat side of the 385. This way, the order is 3-1-2.