[xTelepathetic]

I may have fixed my noise problem. I believe the removable U-shaped portion case was not attached properly to the base. I had left it slightly open to help debug the noise and to quickly swap tubes in and out. Having it inserted all the way into the base with no gaps seemed to have helped a lot, though it may have also been the nice wack I gave it to force it it. Problem solved for now??

 

[xTelepathetic]

The saga continues- the tube amp is not fixed and is not ok. The buzz/hum came back worse so I took the HA-1A MKII to a local repair shop specializing in Guitair Tube Amplifiers to get some basic troubleshooting. The expert found a 120Hz hum output by both channel outputs. Probing the tube sockets, there is too high of a voltage across the control grid of the tubes which can damage them- he was shocked that my tubes were not fried. Finally, the main PCB of the amp has a constant non-zero DC voltage. Resistors that should experience a voltage drop have no voltage drop. The PCB itself is conductive like old Fender Guitar Amps that had to be recalled.

The amp is from 2018 and is out of warranty. I am the second owner. Any advice on how to proceed @Andykong?

 

[Andykong]

The saga continues- the tube amp is not fixed and is not ok. The buzz/hum came back worse so I took the HA-1A MKII to a local repair shop specializing in Guitair Tube Amplifiers to get some basic troubleshooting. The expert found a 120Hz hum output by both channel outputs. Probing the tube sockets, there is too high of a voltage across the control grid of the tubes which can damage them- he was shocked that my tubes were not fried. Finally, the main PCB of the amp has a constant non-zero DC voltage. Resistors that should experience a voltage drop have no voltage drop. The PCB itself is conductive like old Fender Guitar Amps that had to be recalled.

The amp is from 2018 and is out of warranty. I am the second owner. Any advice on how to proceed @Andykong?

Since the amplifier is out of warranty service and you are not the original owner, so you won't be able to vet support from local dealer, you'll need to send the amplifier to Cayin in Zhuhai for inspection/repair.

Please send an email to service@cayin.cn and describe your problems to our service team. Cayin will charge parts and labour cost plus return shipping.

 

[xTelepathetic]

Since the amplifier is out of warranty service and you are not the original owner, so you won't be able to vet support from local dealer, you'll need to send the amplifier to Cayin in Zhuhai for inspection/repair.

Please send an email to service@cayin.cn and describe your problems to our service team. Cayin will charge parts and labour cost plus return shipping.

Much appreciated Andy! Thank you!

Email sent! Now we wait!

 

[dpump]

@xTelepathetic: Before you send your amp off, I would try another rectifier tube. May not fix your problems but it's worth a try.

 

[xTelepathetic]

@xTelepathetic: Before you send your amp off, I would try another rectifier tube. May not fix your problems but it's worth a try.

Hey! Thanks for the suggestion. I have tried some different 12DT5s in the amp but the noise is always present :c

I sent it to Fuchs Audio and am hoping that they can further diagnose the problem

 

[xTelepathetic]

Final update:

Fuchs Audio could not find anything wrong with the Cayin HA-1A MK2. Using the stock tubes they said:

We ran this thing for a few hours, I had a few people give it a listen, as well as measuring the noise floor.

We’re just not seeing anything. It sounds great, but no hum. We tried all settings. The only noise we heard was tapping the 12AX7’s made a ringing noise, which is normal.

I have the amp back now, but the hum and static is even worse. I have tried turning off all electronics around the amp, all electronics in the same room as it, and switching rooms to test it. Static and hum remain in all cases. To make it more interesting, I picked up a Feliks Elise MK2 and have the Elise in the same location where the Cayin was in my room. I am using the same power cable and RCA cables, and there is 0 hum, hiss, or buzz—absolutely pitch black. At this point, I am out of ideas and it is obvious that the Cayin amp is not viable in my current setup.

I am utterly confused as to how one tube amp can operate perfectly in the same environment and conditions while another is an absolute nightmare. I don't understand how one repair place can tell me the amp is working perfectly while another says the opposite. I want to love the Cayin amplifier so badly. It is a beautiful unit. The variable output impedance is amazing! You can go from a warmer solid-state sound to tubey goodness with a flick of the dial. The 12AU7 tubes used in the output stage are easily found, can be cheap (although nicer 12Au7s should definitely be considered), and affect the sound in such a way that tube rolling is possible, impactful, and most importantly FUN! The Cayin would have been perfect for me but whatever is going on with my unit makes it impossible to use and enjoy. I would like to sell the Cayin to get back some of the money that I spent on it, but I can not promise any buyer that they will have a good experience with THIS PARTICULAR unit. If they are lucky, the amp will be perfect just as Fuchs Audio described. If unlucky, they will have an experience similar to mine, be disappointed in their purchase, and efficiently have wasted a large amount of money.

In closing, I would like to thank @Andykong, the seller that I purchased the Cayin amp from, and Rich from Fuches Audio. I have bothered you all quite a bit about this amp and the problems that I have had with it, and I appreciate you both taking the time to respond to me, offer suggestions, and work toward a solution. Although this is a disappointing resolution, I sincerely appreciate all the time and effort that you all have spent trying to help me. Thank you.

 

[Shane D]

Final update:

Fuchs Audio could not find anything wrong with the Cayin HA-1A MK2. Using the stock tubes they said:


I have the amp back now, but the hum and static is even worse. I have tried turning off all electronics around the amp, all electronics in the same room as it, and switching rooms to test it. Static and hum remain in all cases. To make it more interesting, I picked up a Feliks Elise MK2 and have the Elise in the same location where the Cayin was in my room. I am using the same power cable and RCA cables, and there is 0 hum, hiss, or buzz—absolutely pitch black. At this point, I am out of ideas and it is obvious that the Cayin amp is not viable in my current setup.

I am utterly confused as to how one tube amp can operate perfectly in the same environment and conditions while another is an absolute nightmare. I don't understand how one repair place can tell me the amp is working perfectly while another says the opposite. I want to love the Cayin amplifier so badly. It is a beautiful unit. The variable output impedance is amazing! You can go from a warmer solid-state sound to tubey goodness with a flick of the dial. The 12AU7 tubes used in the output stage are easily found, can be cheap (although nicer 12Au7s should definitely be considered), and affect the sound in such a way that tube rolling is possible, impactful, and most importantly FUN! The Cayin would have been perfect for me but whatever is going on with my unit makes it impossible to use and enjoy. I would like to sell the Cayin to get back some of the money that I spent on it, but I can not promise any buyer that they will have a good experience with THIS PARTICULAR unit. If they are lucky, the amp will be perfect just as Fuchs Audio described. If unlucky, they will have an experience similar to mine, be disappointed in their purchase, and efficiently have wasted a large amount of money.

In closing, I would like to thank @Andykong, the seller that I purchased the Cayin amp from, and Rich from Fuches Audio. I have bothered you all quite a bit about this amp and the problems that I have had with it, and I appreciate you both taking the time to respond to me, offer suggestions, and work toward a solution. Although this is a disappointing resolution, I sincerely appreciate all the time and effort that you all have spent trying to help me. Thank you.

That is a tough story.
Three options available and none are very palatable:
1) Throw it away and lose all the money.
2) Sell it and rip someone off.
3) Send it to China, spend a bunch of money and hope it is actually fixed. And stays fixed.

Sorry to say, but no happy ending for you. The downside of buying used. We all (most?) take the chance for the huge savings. But occasionally...

 

[Twizzleshnizzle]

That is a tough story.
Three options available and none are very palatable:
1) Throw it away and lose all the money.
2) Sell it and rip someone off.
3) Send it to China, spend a bunch of money and hope it is actually fixed. And stays fixed.

Sorry to say, but no happy ending for you. The downside of buying used. We all (most?) take the chance for the huge savings. But occasionally...

I'm sure many have good experiences with their units. I personally did not, and found a distracting level of hum on both units I've owned (seemed incredibly sensitive to electrical interference), as well as issues where the solder for the LEDs under the tubes would easily fail (micro fractures I suspect).

It's a gorgeous looking tube amp. It has the potential to sound great. But I don't trust it for a second sadly.

 

[Shane D]

I'm sure many have good experiences with their units. I personally did not, and found a distracting level of hum on both units I've owned (seemed incredibly sensitive to electrical interference), as well as issues where the solder for the LEDs under the tubes would easily fail (micro fractures I suspect).

It's a gorgeous looking tube amp. It has the potential to sound great. But I don't trust it for a second sadly.

I was just referring to used products in general. But, tube amps seem be more prone to problems than most items. Headphones and SS amps seem to go on for years with little to no problems.

 

[xTelepathetic]

That is a tough story.
Three options available and none are very palatable:
1) Throw it away and lose all the money.
2) Sell it and rip someone off.
3) Send it to China, spend a bunch of money and hope it is actually fixed. And stays fixed.

Sorry to say, but no happy ending for you. The downside of buying used. We all (most?) take the chance for the huge savings. But occasionally...

Sadly you are exactly right. In speaking with Cayin support, the cost to ship the unit to China, much less round trip, is astronomical. Being out of warranty, there would be a charge to "repair" the unit as well. In speaking with the previous owner, the unit worked flawlessly. This matches Fuchs' description of the unit as well. Both are reputable and I fully trust both of their words. Unfortunately, my experience with the same unit is jaded and does not match theirs at all. It is fully possible that there is SOMETHING wrong with my setup/living situation. Bad electrical wiring, a router too nearby, maybe it is the dreaded 5G cell towers (this is a JOKE). Whatever the reason may be, the Cayin is just incompatible with my setup.

I would love to be able to sell it and recoup some of the money, but I do not want someone to have the same experience. With the experience of others in mind though, maybe I am the outlier and this is unique to me. Consequently, I don't want to throw it away because it's perfectly working. If you don't mind some hiss/static, the unit does work flawlessly. Between having it inspected twice, both with different results, I have spent another $250 to have the amp examined with no repairs made. My first diagnosis was that something was wrong and the manufacturer needed to fix it while the second was that it is working perfectly. Now, not only have I sunk money into the unit itself, but also roughly a third of its price solely to see if something is wrong with it... as this is now a $1000 endeavor, this chapter does need to come to a close. However, there may be a fourth option available:

4) Sell the unit as damaged to get some form of money back, and potentially a surprised buyer who ends up with a now working unit

My intent though is not to cause a fuss. Like you said, a lot of us buy used to get a good deal. 99.999% of the time, this works out flawlessly. I am in the unfortunate situation where this was not the case. But like I said, I appreciate the effort given by all parties involved in an attempt to remedy it.

 

[xTelepathetic]

I'm sure many have good experiences with their units. I personally did not, and found a distracting level of hum on both units I've owned (seemed incredibly sensitive to electrical interference), as well as issues where the solder for the LEDs under the tubes would easily fail (micro fractures I suspect).

It's a gorgeous looking tube amp. It has the potential to sound great. But I don't trust it for a second sadly.

Out of curiosity, did the hum with your units increase as you raised the output impedance? It ranges from somewhat audible on the lowest output impedance to distractingly loud on the highest. As far as electrical interference, I suspected that it could have been due to being plugged into an outlet extension (plugging directly into the wall did not remedy this) or using the Cayin without the top on as I like to roll tubes frequently. Using the unit with the top on did not fix the issue. I would love for electrical interference to be the root of all this, but I have no way of proving this. Relocating to another room I experienced the same level of hum. Also, I did have one of the tube lights go out, though I believe that it is unrelated to the problem at hand.

 

[Shane D]

Sadly you are exactly right. In speaking with Cayin support, the cost to ship the unit to China, much less round trip, is astronomical. Being out of warranty, there would be a charge to "repair" the unit as well. In speaking with the previous owner, the unit worked flawlessly. This matches Fuchs' description of the unit as well. Both are reputable and I fully trust both of their words. Unfortunately, my experience with the same unit is jaded and does not match theirs at all. It is fully possible that there is SOMETHING wrong with my setup/living situation. Bad electrical wiring, a router too nearby, maybe it is the dreaded 5G cell towers (this is a JOKE). Whatever the reason may be, the Cayin is just incompatible with my setup.

I would love to be able to sell it and recoup some of the money, but I do not want someone to have the same experience. With the experience of others in mind though, maybe I am the outlier and this is unique to me. Consequently, I don't want to throw it away because it's perfectly working. If you don't mind some hiss/static, the unit does work flawlessly. Between having it inspected twice, both with different results, I have spent another $250 to have the amp examined with no repairs made. My first diagnosis was that something was wrong and the manufacturer needed to fix it while the second was that it is working perfectly. Now, not only have I sunk money into the unit itself, but also roughly a third of its price solely to see if something is wrong with it... as this is now a $1000 endeavor, this chapter does need to come to a close. However, there may be a fourth option available:

4) Sell the unit as damaged to get some form of money back, and potentially a surprised buyer who ends up with a now working unit

My intent though is not to cause a fuss. Like you said, a lot of us buy used to get a good deal. 99.999% of the time, this works out flawlessly. I am in the unfortunate situation where this was not the case. But like I said, I appreciate the effort given by all parties involved in an attempt to remedy it.

If I were in your shoes, I would try to sell it while being VERY open about the problems you have observed. You will likely not get $1K or even $750.00. Maybe ask $500.00 and some DIY guy might be willing to pay you a few hundred dollars to tinker with it.

Then just shrug off the loss and move on. Do you own that Feliks amp or were you just borrowing it? Maybe Feliks is the path to future happiness?

 

[xTelepathetic]

If I were in your shoes, I would try to sell it while being VERY open about the problems you have observed. You will likely not get $1K or even $750.00. Maybe ask $500.00 and some DIY guy might be willing to pay you a few hundred dollars to tinker with it.

Then just shrug off the loss and move on. Do you own that Feliks amp or were you just borrowing it? Maybe Feliks is the path to future happiness?

I purchased the Feliks. Found a good deal on it and figured it would be cool to try a different tube amp to compare sounds and see if it worked better than the Cayin. I LOVE how it sounds, though I wish tubes for it were a bit cheaper! The Elise definitely a different type of tube amp though. I think the Cayin at max impedance sounds a bit tubier while the Eslise is more detailed.

 

[Shane D]

I purchased the Feliks. Found a good deal on it and figured it would be cool to try a different tube amp to compare sounds and see if it worked better than the Cayin. I LOVE how it sounds, though I wish tubes for it were a bit cheaper! The Elise definitely a different type of tube amp though. I think the Cayin at max impedance sounds a bit tubier while the Eslise is more detailed.

Sounds like my set-up, (on a lower budget):

1) Little Dot MK9. Very tubey sound that I enjoy, but it gets Super hot, right out to the volume knob. If you pause the music and jack the volume, there is a loud hum. In the regions I listen at, I don't hear anything except sweet music.

2) Schiit Valhalla 2. Crisp and clear sound, with a bit of thickness. But I would not call it very tubey at all. I like it in rotation with the MK9. Going back and forth is fun.

And tube prices aren't bad with either unit (6SL7's and 6922's).