Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Julyan9 on July 02, 2018, 04:03:49 AM
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Hello!
I finished the crack around a week ago. I absolutely love it. My problem is that after a few days of listening a slight cracking sound appeared on the right channel. I have re-soldered all the connections, and there were some bad ones on 3L, 1L, the grounding point near the power inlet and the 2 black wire meeting point on the headphone jack.
At first I thought I solved the issue when I soldered the grounding jack and I didnt hear the crackling anymore. I then added the speedball but the noice was there again. Then I left the amp on for 8 hours, and when I woke up the sound was a lot louder than before, it was very prominent. I had to go to work so didnt have time to chopstick it at the time. Then after the amp had been on continously for 16 hours there was no noise again when I was starting to debug it. I wait for a couple of hours and its there again but its very silent and it comes and goes so its hard to test what connection might be making the sound. Only time something changed when I was poking the connections, was when I found the loose connection on the headphone jack. I tried to scotchbrite the 12au7 pins but that didnt help either. I ordered a new 12au7 to see if it helps. Sometimes the crackling varies when I poke the 12au7 and sometimes it doesnt so I dont know if that is the cause or not. I have gone over the solderings over so many times now that I dont know where to go with that. Any tips on certain points I should re-check one more time?
Also the crackling doesnt happen right after I turn on the amp but it comes and goes after the amp has been warming for a while. Volume pot position doesnt affect the intensity of the sound.
Thanks for any tips.
edit.// To add I'm using Computer->R2R-11 dac output->Crack->HD600. I have tried it with a different cable to the HD600 and with G4me zero senn gaming headset and the same thing happens. The sound was first coming from the left channel, but im pretty sure that I didnt have the hd600 connected the right way when I first used it. IT would be weird for the sound to jump to other channel after some re-soldering wouldnt it?
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It might help if you can post some photos of your build.
This is indeed almost always a solder joint not doing its job.
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Its surprisingly difficult to take photos of components. I first tried with my dslr but that wasnt going to happen.
Noticed that B1 needs some more solder for sure.
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A little more solder and more heat will get those to flow out properly and I think your noise will go away. I'd also go through and trim and leads that are poking out. I've circled three in this photo that could cause some serious problems down the road.
-PB
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Yeah I will fix those tomorrow. I'll also add solder to B1 and see if it helps any. My iron just broke on its own so I have to get a new one :( I didn't trim all the leads yet because the pliers I'm using are bad and I can't fit to that narrow place with them.
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Pliers? You need a pair of "flush cutters", check Google images. Pay a little more for extra life and reliable cutting. The ones with black "flat" blades are usually very sharp but prone to breaking off a blade if try and cut something a bit too thick.
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Pliers? You need a pair of "flush cutters", check Google images. Pay a little more for extra life and reliable cutting. The ones with black "flat" blades are usually very sharp but prone to breaking off a blade if try and cut something a bit too thick.
Yeah sorry english is not my first language, i meant flush cutters. I took the amp with me to work and used the gear there to go over all the solders and then used some ESD flush cutters to trim the leads as short as I could. For some reason I think the amp sounds a bit better now and I have not been able to hear the crackling sound anymore. Ill give it this evening and see if it appears again.
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I think the origin of the sound may be the A3 connection. I think its the only tab i have forgotten to redo. The sound appeared when i took a toothpick next to the led and while poking at the connections a2-a5 region.
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The A3 connection looked OK in your photos. The center pin of the 9 pin socket might be a different story though.
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I re-did the center pin but now that I looked at it again I think the black wire could use some more solder. Maybe poking at the lower A connections move the center pin and that makes the sound. I will be wiser tomorrow. Thank you for tips and help.
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Now after some re-flowing on the smaller tube socket, the sound is now coming from left channel instead of right. So i did something right and something wrong while doing this. Still same channel. The sound is always more prominent when poking around the socket, I just dont know what more to do about it. Surely the issue is in that region since poking the connections makes the sound happen.
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Post another picture. Today is the 4th of July holiday in the US so you might not get a reply from the Bottlehead team today.
Try wriggling the wires one at a time going to the 9 pin socket to see if you can identify one that is causing the issue. It’s possible to nick a wire when stripping which later breaks just under the insulation. That could be your problem if one wire causes the problem but it’s well soldered to the socket.
Beyond that be patient and wait for the BH team to respond.
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I detached the black wire coming from the potentiometer to the center pin and replaced it, didnt help, poked some more and A3 might have been making some noice. now there is a slight hiss on left channel that wasnt there before. right channel still doing the same thing as before.
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The wire at A6 should be bent around the terminal and resoldered as well.
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I changed the red wire also going to A6 and properly crimped it over but that didnt help either. I've been putting off fixing A9 cos I think I need to remove the center black wire to make room. Attached a pic of the small socket
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I'm running out of ideas what to do I did the grounding test.
Measure resistance through this grounding path:
It jumps to the 2 left lugs of the volume pot, measure both lugs. Then it jumps to the back to the RCA jacks. Measure to the outer jacket of the RCA jacks. OK
From the top left lug of the volume pot there is a grounding jumper to the two bottom lugs of the headphone jack. The jack in the picture may be different than what is being delivered today. Measure to both headphone jack lugs. OK
The power supply ground comes from those bottom headphone jack terminals to terminal 12. Measure to terminal 12. From there it jumps to terminal 14 and ends at terminal 20. Measure to both. Cant get a reading from bottom hp jack terminals to 12. 12->14 also blank and 14->20 too. Ground ok from hp jack lower terminals to 20
Also from terminal 3 you go to the center lug of the 9 pin tube socket. This is the ground route for the LEDs in the cathode circuits. Measure here. OK
The heater (AC) supply gets its ground from a wire from transformer terminal 4 to terminal 22. Measure both. This I didn't understand, 4->22 gives no reading but what is supposed to be the starting point of this.
Other points that should be a solid ground are pin 8 of the large tube, pin 4 and 5 of the small tube, T8, T11, T14, T16, T17, T20, T22 and the ground post on the IEC power connector, the one with the bare wire to the chassis. OK if i did this part correctly
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Cant get a reading from bottom hp jack terminals to 12.
These are connected by a piece of wire. If they don't measure as being connected by that piece of wire, then you have a solder joint at one end or the other that isn't doing its job. It's very common for the solder joint on the headphone jack end to not flow around both wires, so I would check there.
The heater (AC) supply gets its ground from a wire from transformer terminal 4 to terminal 22. Measure both. This I didn't understand, 4->22 gives no reading but what is supposed to be the starting point of this.
What version of the Crack do you have? (If there's green wire in it, it's the newest one). The 6.3V AC winding gets its ground from the ground lug back by the IEC power entry module unless you have a previous version of the kit. The place to measure this reference would be B7 and B8.
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HP jack to 12 is fixed now, i still cant get anything from 12->14 or 14->20 but hp jack to 20 works fine.
Also from IEC ground lug to B7 and B8 is ok
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Consider reheating and flowing those joints to get good ground continuity throughout.
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Could that also help with the sound on other channel or are those two completely separate issues?
All grounds are good. Don't tell anyone I was trying to measure them from the transformer instead of the terminal strips 8)
Attached a pic of the HP jack as of now. Im going to reflow everything one last time and see if that helps.
Left the amp on overnight again, same thing happens . When I use the amp normally and it's on like 4-6 hours the sound is barely noticeable. When I leave the amp on overnight and it has time to warm, the sound is very prominent after.
edit no5. Again I reflowed over the whole circuit with 0 change
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I was wiggling B4 and B1 and reflowed B4 and that sorted out B4. Swapped the whole wire from B1 to L1 since both ends looked a bit scuffed. Poking at the joints doesn't affect the sound anymore but its still there like before.
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The next thing to do is to find a wooden chopstick and a cheap pair of headphones. With the cheap headphones on and plugged into the amp with the amp upside-down, poke around the amplifier with the wood chopstick until you can activate the noise, then you'll know where the issue is.
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The next thing to do is to find a wooden chopstick and a cheap pair of headphones. With the cheap headphones on and plugged into the amp with the amp upside-down, poke around the amplifier with the wood chopstick until you can activate the noise, then you'll know where the issue is.
Yeah I've been doing that for days. The noise is not there all the time and some times very faint. I cant find any more connections that make it come or go. I've fixed all I thought were the issue but apparently werent. Could be any of the red wires. I go all the red ones over once more.
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If the noise is not persistent, it would be a good idea to look into external sources. For example, any appliance with a motor in it (fridge, washing machine, dryer, bathroom fan) or a switching power supply can set things off. Your phone and/or wifi router can also broadcast periodic noise that can get into components.
Generally folks find it helpful to take their amp to a different location (office or a friend's house) to see if it behaves in the same way in a different environment.
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Did all the red ones again for the tenth time. Still the same. Yeah its not persistent. Sometimes the amp can be silent for a couple of minutes or more before it happens again. Make the chopstick test very difficult.
I tested it in another room and switched off wifi. Still there. If I don't get this to work during the weekend I'm just going to send it back and pay for the repairs. I will be baffled if its still a cold solder when I have reflowed all joints 10 times and swapped couple of the wires.
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With speedball installed should I still get the 2.9K ohm resistance from 12U to B3 and B6? I cant get a reading anymore. Same goes for 12U to terminal 7 and 9. It passed the test earlier.
Also from 12U to Left RCA center pin I get 115 but to Right its 122.5
I may be grasping at straws here but I'm running out of ideas
Took new readings from the Speedball circuits aswell (havent touched these since the problem was even before speedball, which i realized only after I installed speedball, thought I fixed it before)
Large Board OA 63.7 OB 60.7 G 0 B+ 137.7
Small Board OA 33.8 IA 138 B-A/B 0 to 1 IB 137.7 OB 37.5
These are by using 234V wall socket
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Your boards are not working properly. Getting 38V out of the small board is likely the root cause of the problem. Your high voltage rail is also low.
Can you pull the 6080, leave the 12AU7 in, then let me know what the OA and OB voltages are on the small board?
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OA 28, OB 31
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Flip that board over and resolder all of the solder joints, especially on the MJE350. Can you post some photos of that area of the build? Are the LEDs on the socket lighting?
You're only passing about 1/3 of the current through the small board that you should be.
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Yes sir, all the LED's are working, the ones on the small board seem a bit dim though. I will go over the small board now and measure again after
Went over the soldering, IB and IA got up to 175 now but OB and OA are the same as before.
Edit. Tried to reflow the center legs again couple of times to no avail. The solder moves around the leg but the numbers are the same from OB and the center leg
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Went over the soldering, IB and IA got up to 175 now but OB and OA are the same as before.
IB and IA voltages function independently of that board. If they have changed significantly over the course of your work, that indicates a loose or broken wire that is acting as a bottleneck to the circuit.
There's also still a small possibility that there's still a grounding issue in your amp. Try measuring the OA and OB voltages with terminal 3 as your ground reference (or B-A/B on the small board if that's easier).
-PB
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It got up to 175 from 138.
OB 159 and OA 148 from terminal 3. Same results from B-A/B
These are with the small tube only
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Small Board OA 33.8 OB 37.5
OB 159 and OA 148 from terminal 3. Same results from B-A/B
Which terminal were you using for ground before 3? For the second set of results, you have the 12AU7 in the socket hopefully (like the first set of measurements).
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Which terminal were you using for ground before 3? For the second set of results, you have the 12AU7 in the socket hopefully (like the first set of measurements).
"OA 28, OB 31" This was the result using the 12AU7 only
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Large Board OA 63.7 OB 60.7 G 0 B+ 137.7
Small Board OA 33.8 IA 138 B-A/B 0 to 1 IB 137.7 OB 37.5"
These were taken with both tubes on like the manual suggested.
I was using 12U as ground before 3.
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If your OA/OB voltages on the small board with just the 12AU7 installed are different depending on whether you are grounded at 3 or terminal 12, then terminals 3 and 12 are not well connected and you need to reflow all of the solder joints on the ground path (black wires from the RCA jacks to the volume pot, volume pot to terminal 3, terminal 3 to headphone jack/9 pin center pin, headphone jack back to the power supply, and black wires in the power supply back to the diode bridge).
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They are the same from terminal 12 and 3
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I would reflow all of the solder joints on the small PC board. Having that super low voltage indicates that nearly no current is flowing through the tube.
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I would reflow all of the solder joints on the small PC board. Having that super low voltage indicates that nearly no current is flowing through the tube.
Nvm the numbers are actually different, ill reflow the ground path now.
so from terminal 12 and terminal 3 to OB on small board 159 and 147.6 to OA
The problem is I confused the 12U to the transformer 12 pin and not to the 12 on terminal strip.
The numbers from terminal strip 12 are way higher.
both tubes on
small board: OB 162 OA 150.2 IB 425 IA 425 B-A/B 0
big board: OB 232 OA 241 B+423 G 0
I did the check to A2/A7 and both sit at 0 with all LED's lit
If the heater (AC) supply ground is tested from E to B7/B8 all ground resistance path checks passed.
Is there a path that should end to T22?
Edit://
What could cause the high voltages?
Pics of the small PCB, I can't get the solder to go nice and smooth and shiny on the top side of the board. I've tried warming it more and more but nothing seems to happen. The solder is moving on both sides of the board.
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Ok so I got a meter I actually know how to use and that works 100%.
Numbers are with both tubes attached.
Small board:
OA 70
IA 193
B-A/B 0
IB 193
OB 75
Big board:
OA 110
OB 106
G 0
B+ 193
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OK, those are working voltages!
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OK, those are working voltages!
The intermittent sound is still there though on right channel :(
Is there anything else than reflowing all joints for the 30th time that could help?
I think I will reheat and desolder the joints and warm and apply new solder. The first soldering iron I was using was super bad and didn't keep the heat well enough. I have heated all joints numerous times but that just doesn't help
Edit:/ So I changed the wire from potentiometer to 9pin middle again ja made sure the connection is good. Also resoldered T3. 0 change.
I took the solder out of the joints with wick, reheated and added smaller amout of solder cos I thought maybe I used a bit much on the first times. Still the same sound is there even after not just reheating but resoldering all the joints. I also improved some of the subpar physical connections
Voltages changed ever so slighty after this overhaul. At some point during this there was all sorts of weird hisses ja sounds from both the channels at different points but now left channel is dead quiet again ja right still has the same crackle .
Only thing I haven't done is roll another 6as7g in.
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If I had a wire broken from the inside near a solder, wouldnt I be able to detect that with the chopstick test?
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The chopstick test is great for finding broken wires.
You might have environmental noise that is only being picked up in the right channel. Can you pack your Crack up and take it to work with you for the day? That would give an alternate data point in terms of noise performance.
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The chopstick test is great for finding broken wires.
You might have environmental noise that is only being picked up in the right channel. Can you pack your Crack up and take it to work with you for the day? That would give an alternate data point in terms of noise performance.
Sure I can test that on Monday. That's what I thought. 'Im just running ideas since I resoldered the whole circuit, changed a couple of wires and the issue still persists. I'm mostly testing without RCA's connected but that doesnt change the sound at all.
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I went to the basement where the bomb shelter / storage room is and its the same.
I was wondering if maybe the fact that I live in an older apartment where only the kitchen and bathroom has to have grounded Schuko sockets matter, but seems like it doesnt.
Should I still go the circuit over one more time? It would be nice if there was even the slightest of change after all that soldering and stuff, but there been no improvements
Only wires that maybe could have an issue and that I haven't changed are the ones connected at T3 but no matter how much I try and yank or poke the wires there is change.
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Oh man, you're giving me flashbacks. I lived in a high rise apartment building when I was in high school in the 70s. I'm remembering the fallout shelter signs in the basement.
Unfortunately it's always harder to diagnose this kind of thing without being able the hear the noise in person. I'm gathering this is a new build? Some times the noise is coming from a tube and may go away as the tube cooks in from several hours of play. Or maybe it's a socket connection. Along with testing the wire connections underneath, have you tried rocking the tubes in the sockets a little to see if that makes the noise come and go? Cleaning the tube pins can sometimes help.
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Oh man, you're giving me flashbacks. I lived in a high rise apartment building when I was in high school in the 70s. I'm remembering the fallout shelter signs in the basement.
Yeah exactly like this!
It is a new build indeed.
I did clean the tube pins but that didn't help. Manipulating the tubes has no effect. Only thing I think affects is when I poke around the red wires on the underside, but there is not 1 place that makes it any more than the other. Its like the whole red path makes it. Or it just happens to crackle at that specific time.
soldered speedball again and voltages improved a bit:
Small board:
OA 70
IA 191
B-A/B 0
IB 190
OB 69
Big board:
OA 106
OB 106
G 0
B+ 193
Edit:/
MAN this amp is baiting me so hard. I was doing reflowing and whatnot, turned the amp over added the tubes and did some more chopstick testing. I hear the same freaking sound again and then I see I forgot to add solder to the connection from hp jack to 6L, I poke the connection and when i press the wire from the middle down with my finger the amp goes dead silent. The quietest I have ever heard it. Im like this is it. The 6L end of the terminal had the wire just go straight to the hole and soldered, so there was no proper physical connection. I went and bent the wire over the terminal and pressed tight, soldered and I was SO HOPEFUL. I power the amp and everything is the same as before. Even the voltages went up the old where they are a bit higher. What are the changes that after I have redone all circuits, swapped wires etc. etc. there would still be a cold solder or a bad wire after the chopstick test has no effect, and I can sometimes make the sound go away with wiggling the small tube, but so I can with wiggling random wires from underneath.
Is there any chance that the 6as7g could be the culprit?
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I'd let the amp run for 50 hours to see if the tubes cook in.
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I'd let the amp run for 50 hours to see if the tubes cook in.
Ill try it! Maybe I just nicked all wires that affect right channel and none of the left channel ones :D I had 1 not that good physical connection on the red wire going from A7 to the potentiometer(I had just weaved the wire through the terminal in the jack but hadn't fold it over.) That didn't do anything. Ill let the amp run now on its own for a while. Do i keep headphones in it and play music or just let it go on its own?
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You can just let it idle.
If after the 48 hours the noise persists, try to lay hands on a film capacitor that's between 0.1uF and 1uF and rated at 250V. These are pretty easily found at your local electronics store, and will be handy for another test.
-PB
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I will do that. I really appreciate the time you have taken to try and help me with this issue.
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I really appreciate the time you have taken to try and help me with this issue.
Just a side note. Wow, this support is so impressive. I can't remember ever seeing this level of support for a product by the developers and designers themselves. This is great. I'm having fun following all these Crack builds as I go through mine at a snail's pace. I just wanted to say it's noticed and appreciated even if not my project directly; you guys are the best.
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Thanks very much for the kind words, we really appreciate it. We figured out years ago that the moment of truth when you start the project up can be the tipping point on whether you get satisfaction from the project. Everyone has to climb the learning curve, and everyone makes mistakes. So that particular moment when something doesn't work right and frustration can start to set in is what we try to be most sensitive to. The kits are designed with this in mind and the layout, and assembly and test procedure reflects the desire to make it as easy as possible to get through the rough bits. Having a place to ask questions is the other important ingredient in the recipe.
With the Crack kit what we want to do is help people learn the basic skills like soldering and using a meter, and deliver a solid design that sounds good. There are plenty of universities teaching electronics theory if you want to climb higher up the curve and become a designer. I like to think we have inspired at least a few customers to head in that direction.
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I really really want to find the cold solder from the kit but its just so annoying when nothing happens after tens of tries :D
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We also learn a lot from providing this tech support. When we revised the Crack 1.0 to the Crack 1.1, almost all of the changes were in response to common trouble spots for the average builder. As we put out new kits, those changes just keep getting folded into everything.
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Does it matter which green wire goes to which terminal from and to B7/B8? I think I just kinda winged it since the manual just says to get the wires from 7 and 9 terminals of the transformer to B7/B8
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So I went to the local store and they only had the one I have attached the picture of. When I got home I remembered that it should have been a film cap instead so that maybe doesn't suit the need here?
If I order this ERO / VISHAY / ROEDERSTEIN MKT 1813 470NF (0.47UF) / 250V (MUSTARD STYLE) POLYESTER FILM CAPACITOR, AXIAL it will be the right one yes?
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That will work. Temporarily solder that cap between 1U and 5U, then let us know if the behavior of the static changes. Be sure to leave the leads super long, as we may end up putting this cap in all sorts of different places as we check each bit of the circuit.
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That will work. Temporarily solder that cap between 1U and 5U, then let us know if the behavior of the static changes. Be sure to leave the leads super long, as we may end up putting this cap in all sorts of different places as we check each bit of the circuit.
1U and 5U was no cigar.
I got some better solder and wick, and I was bored so I went over the red path again, the solders look much better and shinier, but it didn't help with the initial issue. Last solder I had was Sn60Pb39Cu1 and this one is Sn62Pb36Ag2
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What was no cigar? Did you get noise only in one channel or in both channels?
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Same noise on right channel only. I.e. nothing changed
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OK, well that narrows down things a lot. This tells us that the wiring from the input jack to volume pot, volume pot to 12AU7, and 12AU7 to 6080 is all doing OK.
How do the pins look on the 6080 tube? These are all old stock tubes, and sometimes a very heavily oxidized tube pin can be a little noisy.
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OK, well that narrows down things a lot. This tells us that the wiring from the input jack to volume pot, volume pot to 12AU7, and 12AU7 to 6080 is all doing OK.
How do the pins look on the 6080 tube? These are all old stock tubes, and sometimes a very heavily oxidized tube pin can be a little noisy.
Maybe this is a good thing? Still the potential cold solders tho. I had 6080 arrive in mail, (JAN 6080WC) and with that on the amp, i don't hear the sound anymore. What I was wondering if I slightly tap the tube, it only makes a sound on the right channel. Why it doesn't affect both? I don't want to jinx it and will see for a couple of days maybe if the sound returns. Not sure if its just placebo but I think I liked the sylvania 6AS7G better than this tube that I got now. This cost like 4 euros so not a big deal, and it was mainly for counting out the 6AS7G.
I have used some "pro clean"(sort of de-greaser) on the tube pins but that didn't help. I tried with some scotchbrite but that wasn't very successful either. I think I get some fine steel wool and some contact cleaner and see if that helps! The pins look pretty ok and clean to me as is. Its just hard to think that the tube could have been making that noise.
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Yes, nearly all 12AU7 and 6080 tubes we've encountered that made some noises while running quieted down after a few long periods of use.
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Yes, nearly all 12AU7 and 6080 tubes we've encountered that made some noises while running quieted down after a few long periods of use.
I kept it going for the 50h straight but it didn't help.
Ill try and clean the 6AS7G tube tomorrow and see if I can get that to quiet down also. I just have a hard time believing this all could have been caused by the tube. Month of soldering the circuit over and over at least I learned where every component is :D I'm keeping my fingers crossed.
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I think this can be marked as solved. Thank you very much for your time and effort in helping me with this issue.
What I have been experiencing with the new tube is hum on right channel but that is another story. If I lift the amp from the table the hum stops. There was no hum all day yesterday so there is the next thing for me to tackle! (flex)
Edit:
So I got the 0000 steelwool and cleaned the 6AS7G that came with the kit. The right channel still crackles with that tube. I think its not as bad as it was before. Maybe I just ditch the tube all together and just use another tubes and see if they are doing any better.
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Be sure all your hardware is nice and tight!
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Be sure all your hardware is nice and tight!
Have to tighten everything down again. The new 6080 I got that is making the hum sometimes, it feels like the tube is vibrating so much that it is making the hum that way. This is only present when the tube is warming up though I think. The 6AS7G even after cleaning the pins still make the crackle.
Edit:/
Got a Thomson-csf 6080WA today in the mail and its dead quiet.
I have used the other tubes for a while and decided to give the 6AS7G another chance. Still no dice. Seems like that was the problem almost all the time at least.