[JeffMann]

Mine are the same way, and I wouldn't sweat it. Just make sure they are seated all the way in. The 6SN7 and 22DE4 sockets are ridiculously tight, and the 300B are definitely a bit looser on my unit as well. Perhaps part of it is due to lesser number of pins on the 300B's for less frictional contact to the sockets, compared to the drivers and rectifiers?

I personally don't think Cayin should ship the amp with the tubes already installed, because the tubes can come loose during shipping (all delivery services literally throw and drop packages during transit all the time), and if you don't check to see if the tubes are seated correctly before firing up the amp problems can arise. One of my stock Gold Lion 300B's were not seated all the way in when I received my first unit, but I noticed it and made sure it was seated correctly before firing up the amp for the first time.

* A note to new HA300mk2 owners, check to make sure the tubes are seated correctly (all the way in) before firing up the amp for the first time.

I have attached an image of a tube socket for a 300B tube.

I strongly suspect that this is the type of 300B tube socket that is used in the Cayin HA300 amp. The metal clamps look very weak and I can imagine that they have lost secure contact with the pins of the 300B tube because the amp was shipped with the 300B tubes in place. Cayin placed a foam insert in the cage to presumably prevent movement of the 300B tube, but I have found that the foam insert is very loose fitting and it does not actually prevent the 300B tube from moving while the amp is en route from China to Florida (RSM Communications = US Distributor), and then from Florida to Salt Lake City (my home city).

I purchased the Cayin HA300 amp from Arthur Power of Power Holdings Inc. who placed a special order on my behalf because he does not routinely sell the Cayin HA300 amp.

He claims that he can replace the 300B tube sockets with a much better quality tube socket - see https://www.thetubestore.com/4-pin-teflon-gold-socket - that will more securely hold the pins of the 300B tube.

What do you think?

I am also worried about whether that very loud staticky noise (which sounded like a machine gun firing in terms of volume intensity) can damage the driver of my headphones if it happens again. Can a headphone driver be seriously damaged if the 300B tube malfunctions?

Jeff.

 

[JeffMann]

I have attached an image of a tube socket for a 300B tube.

I strongly suspect that this is the type of 300B tube socket that is used in the Cayin HA300 amp. The metal clamps look very weak and I can imagine that they have lost secure contact with the pins of the 300B tube because the amp was shipped with the 300B tubes in place. Cayin placed a foam insert in the cage to presumably prevent movement of the 300B tube, but I have found that the foam insert is very loose fitting and it does not actually prevent the 300B tube from moving while the amp is en route from China to Florida (RSM Communications = US Distributor), and then from Florida to Salt Lake City (my home city).

I purchased the Cayin HA300 amp from Arthur Power of Power Holdings Inc. who placed a special order on my behalf because he does not routinely sell the Cayin HA300 amp.

He claims that he can replace the 300B tube sockets with a much better quality tube socket - see https://www.thetubestore.com/4-pin-teflon-gold-socket - that will more securely hold the pins of the 300B tube.

What do you think?

I am also worried about whether that very loud staticky noise (which sounded like a machine gun firing in terms of volume intensity) can damage the driver of my headphones if it happens again. Can a headphone driver be seriously damaged if the 300B tube malfunctions?

Jeff.

I was wondering whether the following solution is easier to execute and it will not involve sending in my amp for repair/replacement.

I have attached an image showing the interior of the amp. It shows the 300B tube socket. It would seem that if I simply remove the bottom panel of the amp that I will be able to access the 300B tube sockets. I could then use a pair of needle nose pliers to crimp those metal clamps closer together. If that works, then I would not have to send the amplifier back for repair or replacement (presuming it has not been damaged by those events that unfolded when I first used the amplifier).

What do you think?

Jeff.

 

[jamato8]

I was wondering whether the following solution is easier to execute and it will not involve sending in my amp for repair/replacement.

I have attached an image showing the interior of the amp. It shows the 300B tube socket. It would seem that if I simply remove the bottom panel of the amp that I will be able to access the 300B tube sockets. I could then use a pair of needle nose pliers to crimp those metal clamps closer together. If that works, then I would not have to send the amplifier back for repair or replacement (presuming it has not been damaged by those events that unfolded when I first used the amplifier).

What do you think?

Jeff.

Yes, that is what you tighten on a tube socket. I used to test a lot of tubes as I have many, a few 1000 and my testers would get a little loose. I would tighten the socket clamp force. But I am use to it having used tubes for many years and I used them in the US Navy as a radioman (not called that any longer). But I would bend them just a little. and then insert the tube and see if you are getting better contact, pressure on the tube pins. This is not uncommon, to do this. Also as you can tell, the tube will move more because thee are only 4 pins vs. 8 etc. But you still want good clamping force on the pins or you will have issues. Different tube sockets require different methods of fixing the clamping force on the pins. So many people now have never used tubes, so they are used to it or what to do. It isn't a mystery and something you learn to do. It also depends upon the quality of the sockets and most aren't near the quality of what they used to be but then when everything from TVs, radios, stereos, etc., had tubes, is was a different world.

 

[jamato8]

I have attached an image of a tube socket for a 300B tube.

I strongly suspect that this is the type of 300B tube socket that is used in the Cayin HA300 amp. The metal clamps look very weak and I can imagine that they have lost secure contact with the pins of the 300B tube because the amp was shipped with the 300B tubes in place. Cayin placed a foam insert in the cage to presumably prevent movement of the 300B tube, but I have found that the foam insert is very loose fitting and it does not actually prevent the 300B tube from moving while the amp is en route from China to Florida (RSM Communications = US Distributor), and then from Florida to Salt Lake City (my home city).

I purchased the Cayin HA300 amp from Arthur Power of Power Holdings Inc. who placed a special order on my behalf because he does not routinely sell the Cayin HA300 amp.

He claims that he can replace the 300B tube sockets with a much better quality tube socket - see https://www.thetubestore.com/4-pin-teflon-gold-socket - that will more securely hold the pins of the 300B tube.

What do you think?

I am also worried about whether that very loud staticky noise (which sounded like a machine gun firing in terms of volume intensity) can damage the driver of my headphones if it happens again. Can a headphone driver be seriously damaged if the 300B tube malfunctions?

Jeff.

Yes, the ones in the link are much better and I doubt you would ever have an issue with them. If I bought the amp, I would change them out. Sad that they don't use much better quality tube sockets.

With a high enough volume, of course it could damage the drivers.

The sockets for being teflon are inexpensive compared to others I have seen in the past that use teflon. I prefer ceramic bases as teflon can deform but I would check with the company selling them.

 

[JeffMann]

Yes, that is what you tighten on a tube socket. I used to test a lot of tubes as I have many, a few 1000 and my testers would get a little loose. I would tighten the socket clamp force. But I am use to it having used tubes for many years and I used them in the US Navy as a radioman (not called that any longer). But I would bend them just a little. and then insert the tube and see if you are getting better contact, pressure on the tube pins. This is not uncommon, to do this. Also as you can tell, the tube will move more because thee are only 4 pins vs. 8 etc. But you still want good clamping force on the pins or you will have issues. Different tube sockets require different methods of fixing the clamping force on the pins. So many people now have never used tubes, so they are used to it or what to do. It isn't a mystery and something you learn to do. It also depends upon the quality of the sockets and most aren't near the quality of what they used to be but then when everything from TVs, radios, stereos, etc., had tubes, is was a different world.

Thank you for your useful comments.

I turned the amplifier sideways and I noted that there are only 8 Philips-type screws that hold the bottom plate in place. In fact, the bottom plate has ventilation grills and when I shine a light through the grills I can clearly see the 4 socket metal clamps of each 300B tube socket. They differ from that photo image in my previous post in the sense that they are gold-plated. I can also see that they are not close together.

I presume that there is no risk of an electrical shock if I attempt to crimp those gold-plated metal clamps closer together - seeing that my main amplifier has been disconnected from the power supply for about 12 hours.

Jeff.

 

[jamato8]

Thank you for your useful comments.

I turned the amplifier sideways and I noted that there are only 8 Philips-type screws that hold the bottom plate in place. In fact, the bottom plate has ventilation grills and when I shine a light through the grills I can clearly see the 4 socket metal clamps of each 300B tube socket. They differ from that photo image in my previous post in the sense that they are gold-plated. I can also see that they are not close together.

I presume that there is no risk of an electrical shock if I attempt to crimp those gold-plated metal clamps closer together - seeing that my main amplifier has been disconnected from the power supply for about 12 hours.

Jeff.

There is normally a drain resistor for the caps, which is proper design but never count on it until you look at the caps. But the power supply is by umbilical so you would disconnect that any way. Taking the tube out of the socket and improving the clamping force should not be a problem. Just don't touch bare wires. Most likely no issue but if you aren't familiar with the layout etc., better to safe than sorry. I have been hit with 720 volts from a cap and it isn't fun smelling you flesh burning. lol

When ever working on electronics take off any good grounding objects, like rings etc. But I doubt you would have issues tightening the clamping force. To me, it is no big thing and I would without doubt, improve the socket force on the pins.

 

[Yggy]

I’ve been testing a DHC Prion 4 headphone cable with Abyss 1266 Phi TCs and the HA-300. I use Forza Audio Noir Hybrid HPC cables but wanted to try something fancier. I didn’t want a cable that added its own sound signature or colouration.

The Prion 4 improved detail, clarity, tonality, and bass tightness, so you get a bit more of everything the HA-300 excels at. The trade-off is a slightly leaner bass but it has more impact because it’s more chiselled and textured.

Looks-wise, the charcoal grey sleeving with copper and silver metallic tracers is gorgeous. It’s not quite as easy to handle as the Noir Hybrid HPC but it’s light and manageable for a summit-fi headphone cable.

 

[llamaluv]

The very loud 'gunshot'-level noise out of the driver is the most concerning thing to me. My vote is a bad tube.

I had a brand new Studio Six once which did not play any music, but when I turned the input selector, the headphone (ZMF Auteur, I think) emitted a very, very loud crack, at least 90dB from a couple feet away. I was thankful that the driver did not break and even more thankful the headphone wasn't on my head (yeeesh).

I sent it back for repair but was told that it turned out to be simply a bad tube (power tube, I believe).

 

[EagleKent]

I just received my Cayin HA300MK2 amplifier today from the US Distributor (RSM Communications in Florida).

The amplifier is malfunctioning badly.

I connected my Susvara headphones to the 4-pin XLR output of the amplifier and it produced sound (of mediocre quality) for about two hours (using a PS Audio PWT CD-Transport => Musician Aquarius DAC => RCA connection to the Cayin HA300MK2 headphone amplifier). Then I noted a loud scratchy/static type of sound intermittently in the left channel. It then became continuous and much louder than the music. That static type of distortion almost sounded as loud as gunshots and it sounded very loud even if the volume control was turned to zero.

I turned off the amplifier for about an hour and when I turned it on again there was no sound coming from the left channel and the sound quality from the right channel was tinny/distorted. I checked the 300B fuses and they seemed to be intact. I switched 300B tubes and then the right channel was dead (silent) and the output from the left channel was tinny/distorted.

What do you think is causing the problem?

There is one fact about this amplifier that really surprised me. I noted that the 22DE4 tubes and 6sn7 tubes are firmly socketed and cannot be moved. However, the 300B tubes seem to just be floating with no grip at socket level. If I gently rock the top of the 300B tubes with my fingertip, I can rock them 1/4"-1/2" in each direction (side-to-side and back-and-forth) and they do not necessarily become vertical again after the movement. Is that normal for a 300B tube, or should the tube's 4 pins be firmly grasped by "something" in the tube socket? I also noted that it is hard to see whether the 300B tubes are on - there is only a faint orange-red glow that is visible when I switch off the lights. Is that normal? Shouldn't the filament produce a stronger glow? Could it be due to the fact that there is very little physical contact between the tube's 4 pins and the tube socket connection?

Jeff.

As a new owner myself I can confirm the 300B sockets are looser than the 6SN7 sockets but not socket itself is loose, it's just the 300B does move around easily while in the 4-pin socket. I also have noise issues from the start with a low buzzing sound which I was able to reduce by plugging it to my Amazon powerboard that have a bit of EMI filtering (not proper power conditioning one like Furman). After a week the buzz is pretty much gone except it does come back intermittently, say 1% of the time. I am also still getting a faint intermittent bell ringing sound as well.
But yesterday I had a revelation or confirmation of what I had read on the various forums concerning 6SN7 tubes being more susceptible to noise and microphonics. My order of 6 pairs of various second-hand 6SN7 tubes from various reputable eBay sellers finally arrived and lo-and-behold, the first pair I tried was completely silent. Furthermore, when I tap on the shelf and casing, no noise through the HP! It looks like a very old tube but no microphonics! The next 3 pairs have very low hum (not buzz) and tapping can be heard through HP but not as much as the stock tubes. The last pair have the same intermittent bell ringing and buzzing as the stock tubes.
I am still burning in the tube amp and if the intermittent buzzing of the stock tube persists after 200 hours I am returning them under warranty as it will be clear I have got bad tubes. The second-hand old tubes I got all sound great and sweeter but the stock Tung-sol tubes still sound more transparent to my ears so definitely want a replacement, especially something I had paid for

Try swapping to another 6SN7 in case you got bad tubes if you haven't already. Worth a try IMO. I had thought it may be my power supply but tube swapping pretty much confirmed it's the tubes. Cheers.

 

[iamdman]

Hello,

I have been looking for a tube amplifier for my HD800s and ZMF VC for quite some time. I was looking at Cayin HA-6A, but I can get a 300Mk2 with 10% off on new item and wondering if its worth to look at 300MK2? Has anyone moved from HA-6A to 300MK2 and if so can you please share your thoughts?


Thanks

 

[EagleKent]

Hi all,
Being new to 6SN7 tubes and now having rolled 5 pairs other than stock I have a question which is for brand new 6SN7 tubes, do we expect them to be completely noise free and not microphonic? I just realized the pair that is completely noise-free and not microphonic is NOS (6N8S/6SN7 Foton Double Triode Tubes Square Getter Same Date VI. 1959'). The other used tubes (6SN7GTA GE 1950, 6SN7GTB Raytheon/Baldwin Black Plates O-Getter, and 6SN7GTA Sylvania) all have some noise and are microphonic.
If new 6SN7 tubes should be noise-free and not microphonic do you have any reputable sellers you can recommend that guarantee noise-free and non-microphonic tubes? I just bought a bunch of used tubes to try as they are cheaper and once I landed on the one I like, I will look to stock up on NOS or new stock of the same.

Thanks

 

[jamato8]

Most of the time the only time you’re going to notice anything that’s microphone like is if you’re tapping on something or if you’re using it in a speaker system and they’re very microphonic picking up everything. Otherwise, I will take a microphonic tube over totally dead quiet one because they tend to add a little bit more life to the music and that is through years of experience. There’s nothing wrong with a little bit of micro phonics in a tube and for many it is normal. It’s just people want to tap on everything tap on the tube and then say hey, it’s microphonic that’s got nothing to do with the ultimate sound that he can produce. Also regarding noise a lot of times a new tube or even a tube that has been used for a while will get a little bit of gas, which is why you have getter inside the tube. Getter, absorbs gases they can overtime leak into the tube. Where did tube is heated up the gutter is more activated and then absorbs. Those gases and a gassy tube can cause some noise. when you buy used tubes you have no idea how much they’ve been used and you will not know the true sound of that tube because even if it measures well, you still don’t know how much and how hard it was used and that sometimes can take the edge off the quality sound of a tube

If there’s any typos in this, sorry I’m using voice to do my typing right now.

 

[jamato8]

Double post

 

[EagleKent]

Most of the time the only time you’re going to notice anything that’s microphone like is if you’re tapping on something or if you’re using it in a speaker system and they’re very microphonic picking up everything. Otherwise, I will take a microphonic tube over totally dead quiet one because they tend to add a little bit more life to the music and that is through years of experience. There’s nothing wrong with a little bit of micro phonics in a tube and for many it is normal. It’s just people want to tap on everything tap on the tube and then say hey, it’s microphonic that’s got nothing to do with the ultimate sound that he can produce. Also regarding noise a lot of times a new tube or even a tube that has been used for a while will get a little bit of gas, which is why you have getter inside the tube. Getter, absorbs gases they can overtime leak into the tube. Where did tube is heated up the gutter is more activated and then absorbs. Those gases and a gassy tube can cause some noise. when you buy used tubes you have no idea how much they’ve been used and you will not know the true sound of that tube because even if it measures well, you still don’t know how much and how hard it was used and that sometimes can take the edge off the quality sound of a tube

If there’s any typos in this, sorry I’m using voice to do my typing right now.

Thanks! That's very good info

 

[Wes S]

Hi all,
Being new to 6SN7 tubes and now having rolled 5 pairs other than stock I have a question which is for brand new 6SN7 tubes, do we expect them to be completely noise free and not microphonic? I just realized the pair that is completely noise-free and not microphonic is NOS (6N8S/6SN7 Foton Double Triode Tubes Square Getter Same Date VI. 1959'). The other used tubes (6SN7GTA GE 1950, 6SN7GTB Raytheon/Baldwin Black Plates O-Getter, and 6SN7GTA Sylvania) all have some noise and are microphonic.
If new 6SN7 tubes should be noise-free and not microphonic do you have any reputable sellers you can recommend that guarantee noise-free and non-microphonic tubes? I just bought a bunch of used tubes to try as they are cheaper and once I landed on the one I like, I will look to stock up on NOS or new stock of the same.

Thanks

Buying quiet tubes is a crap shoot for both NOS and New Production, unless you buy from a vendor that checks for noise. Also, there is not one brand or make that is always quiet. For instance, of my six pairs of RFT 6SN7, a several of the pairs are quit a bit quieter than the rest and they are the exact same tube.

A couple of vendors that check for noise that I have have had great success with, are Vintage Tube Services and Tube World Express. Also, there are some on ebay as well, and they usually put that in the listing.