[Andykong]

So the wife bought me a pair of Electro harmonix 12au7 gold, tube rolling starts earlier than expected.

How long do these usually take to burn in?

Your wife understands your hobby and bought you a pair of 12AU7 as present? That 's some serious blessing, because I sure won't have the knowledge to buy a lipstick for my wife.

You don't need very long hours to burn in the vacuum tubes, run it for 20 hours and you can form your impression already, and the audio signature will be fairly stable after 50 hours. According to the vacuum tube hobbyist, the burn in process actually continuous all through the life of the vacuum tubes and their tubes sound best the day before it died.

 

[Andykong]

Good to know that Cayin has provided refund. In my case, the local repair service has ordered the new board and will replace it. But I have very strong suspicious that it will not fix the problem. next will be refund. 3 months repair waiting is quite hard. I do not understand why Cayin until now did not recall the unit and done proper investigation. Instead of that they prefer the local repair shops all around the world to fix their problems. If it is a faulty parts it can help, but if it is a poor circuit design the local shop will not be able to fix it. Now Cayin try to convince me it is a a faulty parts, but from my radio experience it looks like poor circuit design. I have asked to measure on oscilloscope how clean DC power comes to driver tube 12AU7 (from my point the problem around this area), Also I am thinking to made bypass, take the driver stage from another OLT amp and connect to the Cayin amplification part (KT88) and vise versa to find where is the problem. Regards, Kim

I hope other users are not forming a biased opinion because of the complaints in this thread. For the record, we also offered full refund to @Relaxasaurus. We feel sorry to Relaxasaurus for taking him 2 months of waiting, and we think it's unreasonable to ask him to wait for another 2-3 months, we offered full refund so that we can collect the HA-6A from him and send it back to China for inspection. Relaxasaurus rejected our offer.

 

[Fatdoi]

I hope other users are not forming a biased opinion because of the complaints in this thread. For the record, we also offered full refund to @Relaxasaurus. We feel sorry to Relaxasaurus for taking him 2 months of waiting, and we think it's unreasonable to ask him to wait for another 2-3 months, we offered full refund so that we can collect the HA-6A from him and send it back to China for inspection. Relaxasaurus rejected our offer.

Hi Andy..... if Cayin was able to fix the hissing complaint, I'm sure the owners would want to keep their amps... so far I still haven't read on this thread the fix is found and corrected.

 

[Andykong]

Hi Andy..... if Cayin was able to fix the hissing complaint, I'm sure the owners would want to keep their amps... so far I still haven't read on this thread the fix is found and corrected.

Given the uncertainties and inefficient logistic system worldwide, we think a full refund to customer and collect the amplifier from further study is the best option.

 

[ThanatosVI]

Your wife understands your hobby and bought you a pair of 12AU7 as present? That 's some serious blessing, because I sure won't have the knowledge to buy a lipstick for my wife.

You don't need very long hours to burn in the vacuum tubes, run it for 20 hours and you can form your impression already, and the audio signature will be fairly stable after 50 hours. According to the vacuum tube hobbyist, the burn in process actually continuous all through the life of the vacuum tubes and their tubes sound best the day before it died.

Nah I wrote on a list "possible gifts" with links on where to buy.

We both have such lists for birthdays, christmas and such.

 

[Fatdoi]

Nah I wrote on a list "possible gifts" with links on where to buy.

We both have such lists for birthdays, christmas and such.

a very pragmatic couple... thumbs up

 

[ThanatosVI]

So after some hours with my new pre amp tubes I will leave some impressions.

The New tubes are Electro harmonix 12au7 Gold.
They are very clear, slightly bright with great extension on both sides. Feels like a completely different amp with those.
Since they are so clear and "solid state" like, they feel slightly thin at times.

The sound may be a matter of taste but the universally good news is, that the Hum Sound is nearly completely gone with them.
It has been significantly less than the stock tubes right from the moment I first inserted them, but now after 20-30 hours on them the hum is nearly completely gone (low impedance, triode mode, xlr out)

 

[ThanatosVI]

I know that I nearly write to myself in here ny now, but I got Updates regarding the hum Sound.

Today I rolled back to the stock tubes (Experimenting with a different DAC)
At first I had a huge noise on the left channel, which made me fear I destroyed something.

I then switched to the EH Gold again, where everyghing was silent.
Back to the stock tubes, again huge hum on the left channel
Then I just switched tubes left and right channel, and I am finally back to the little hum I had when I first got the amp

So to me it seems that I simply have a noisy stock tube and the hum could be fixed by replacing it. And that the left tube Socket is more Prone to noise(whixh makes sense to an amateur like me since it is in the middle of the amp)

Of course this might only hold true for planars, and dynamics might get the hum even with dead silent tubes

 

[Gr3g277]

I know that I nearly write to myself in here ny now, but I got Updates regarding the hum Sound.

Today I rolled back to the stock tubes (Experimenting with a different DAC)
At first I had a huge noise on the left channel, which made me fear I destroyed something.

I then switched to the EH Gold again, where everyghing was silent.
Back to the stock tubes, again huge hum on the left channel
Then I just switched tubes left and right channel, and I am finally back to the little hum I had when I first got the amp

So to me it seems that I simply have a noisy stock tube and the hum could be fixed by replacing it. And that the left tube Socket is more Prone to noise(whixh makes sense to an amateur like me since it is in the middle of the amp)

Of course this might only hold true for planars, and dynamics might get the hum even with dead silent tubes

hello my friend,


yes I can confirm that too, mine is more "sensitive" to different stuff like noise, hum, microphonics on the left channell as well.
It is a bit strange cause I have a quad of sylvania 6189, and i found that 3 of them were not usable on the left channel, but good on the right channel.
I definetely think the preamp section is picky with with the tubes.

I think I will work on opening the beast and drawing a basic schematic of what is going on in the preamp section.
maybe I will try upgrading the caps as well... I heard that could give good results regarding hum and microphonics

In the meantime, I am still enjoying this amp so much, I scored a pair of 60's RCA 5814A blackplates triple mica, and they are my favourite so far !

 

[ThanatosVI]

hello my friend,


yes I can confirm that too, mine is more "sensitive" to different stuff like noise, hum, microphonics on the left channell as well.
It is a bit strange cause I have a quad of sylvania 6189, and i found that 3 of them were not usable on the left channel, but good on the right channel.
I definetely think the preamp section is picky with with the tubes.

I think I will work on opening the beast and drawing a basic schematic of what is going on in the preamp section.
maybe I will try upgrading the caps as well... I heard that could give good results regarding hum and microphonics

In the meantime, I am still enjoying this amp so much, I scored a pair of 60's RCA 5814A blackplates triple mica, and they are my favourite so far !

i'll

Can you describe the sound of the RCA 5814A blackplates triple mica?
Since you only need two I consider them affordable.
Are they rather warm or clear, how good is the extension on both sides etc.
Is there something you like in particular about their sound?

 

[Gr3g277]

Can you describe the sound of the RCA 5814A blackplates triple mica?
Since you only need two I consider them affordable.
Are they rather warm or clear, how good is the extension on both sides etc.
Is there something you like in particular about their sound?

I find them comparable to the 6189,

compared directly to the stock EH 12au7, they are definitely warmer but not overly warm as well, I find them pretty neutral, with good extensions on both side
the overall sound is more "liquid", and fairly detailed.
soundstage and separation are good, but no better than the 6189.here I think the EH are a bit more upfront

If you Go on the NOS route , please buy from a reputable reseller, or if you go on ebay, buy only tubes that test good

 

[ThanatosVI]

I find them comparable to the 6189,

compared directly to the stock EH 12au7, they are definitely warmer but not overly warm as well, I find them pretty neutral, with good extensions on both side
the overall sound is more "liquid", and fairly detailed.
soundstage and separation are good, but no better than the 6189.here I think the EH are a bit more upfront

If you Go on the NOS route , please buy from a reputable reseller, or if you go on ebay, buy only tubes that test good

Thx for the impressions

I am not sure yet, if I will go the NOS Route.
However I really like to read about some sound signatures.
Therefore it would be much appreciated if you could share your experience.
I am also interested in the sound of some reissues.
Someone recommended Gold lions, Mullard and the EH Gold which I already have.

For now I will order from tubeampdoctor.
Cayin Support recommended https://btb-elektronik.de/ as well.

Didn't you also order some PSVane not too long ago?

 

[Gr3g277]

Thx for the impressions

I am not sure yet, if I will go the NOS Route.
However I really like to read about some sound signatures.
Therefore it would be much appreciated if you could share your experience.
I am also interested in the sound of some reissues.
Someone recommended Gold lions, Mullard and the EH Gold which I already have.

For now I will order from tubeampdoctor.
Cayin Support recommended https://btb-elektronik.de/ as well.

Didn't you also order some PSVane not too long ago?

I did receive the psvanes but one of them is too noisy to use in this amp, I bought them from china, and I have to send them back before i can get a replacement.
too bad cause the sound was very promising !

what i tested so far for preamp tubes : ( i also have a primaluna speaker amp that in which I can use them )

stock EH12au7 : good tube in ha-6a, a bit bright and upfront for my liking
JJ ecc802S : too noisy for ha-6a, warm and rich, wooly bass in primaluna, short on the top
primaluna shuguang 12au7 : too noisy for ha-6a, bright-neutral, upfront, 2D soundstage, not my cup of tea
GE 6189 & sylvania 6189 : low noise, some are a bit microphonic, very good in ha-6a, neutral to warmish signature, a bit rich mids good extension top to bottom, very good details,
RCA 5814A blackplates triple mica : noise level is same as 6189, low microphonics, neutral sound, great mids, great extension, very balanced
Psvane 12au7-S art series : 1 tube was very noisy from the start,the other as low noise as the 5814, trying to listen a bit, it was quite promising, with brighter signature like the EH, but very good soundstage, and less upfront presentation, I have to try them in the speaker amp, to see if the noise does bother me..


tube amp doctor is my primary source for tubes, you can't go wrong with them !!

I don't have experience with btb-elektronic, I will look at what they have...

PS: don't go too far down the rabbit hole of tube rolling.....

 

[ThanatosVI]

I did receive the psvanes but one of them is too noisy to use in this amp, I bought them from china, and I have to send them back before i can get a replacement.
too bad cause the sound was very promising !

what i tested so far for preamp tubes : ( i also have a primaluna speaker amp that in which I can use them )

stock EH12au7 : good tube in ha-6a, a bit bright and upfront for my liking
JJ ecc802S : too noisy for ha-6a, warm and rich, wooly bass in primaluna, short on the top
primaluna shuguang 12au7 : too noisy for ha-6a, bright-neutral, upfront, 2D soundstage, not my cup of tea
GE 6189 & sylvania 6189 : low noise, some are a bit microphonic, very good in ha-6a, neutral to warmish signature, a bit rich mids good extension top to bottom, very good details,
RCA 5814A blackplates triple mica : noise level is same as 6189, low microphonics, neutral sound, great mids, great extension, very balanced
Psvane 12au7-S art series : 1 tube was very noisy from the start,the other as low noise as the 5814, trying to listen a bit, it was quite promising, with brighter signature like the EH, but very good soundstage, and less upfront presentation, I have to try them in the speaker amp, to see if the noise does bother me..


tube amp doctor is my primary source for tubes, you can't go wrong with them !!

I don't have experience with btb-elektronic, I will look at what they have...

PS: don't go too far down the rabbit hole of tube rolling.....

Which primaluna amp do you have?
I initially planned on getting an Evo 300 but in the end I decided on the Ha-6a

Did you ever compare the headphone out with the Ha-6a?

Thx for the tube sound impressions, seems like it is challenging to find tubes that are silent enough.

 

[Gr3g277]

Which primaluna amp do you have?
I initially planned on getting an Evo 300 but in the end I decided on the Ha-6a

Did you ever compare the headphone out with the Ha-6a?

Thx for the tube sound impressions, seems like it is challenging to find tubes that are silent enough.

I have the basic prologue classic integrated amp, so no headphone out unfortunately.

I did try the speaker out with a balanced adapter cable, with my arya's and it sounded pretty darn good, but it has waaay too much gain without the proper divider network .

So not usable as is as a headphone amp.
That said the cayin sounds better....

I have some mundorf caps coming for the primaluna , if it makes really a difference, I will maybe try upgrading the caps in the ha 6a...

I looked inside and the caps layout is quite unconventional ! 2 .22uf paralleled coupling caps.. never seen that !

1 electrolityc dc blocker, 1 .1uf bypassing it.
And a cathode resistor bypass. The tube sockets are pretty crowded !

The caps are realcaps , the same you find in the dialogue premium stuff from PL.
They changed them in the new EVO series.

I've read somwhere on the web a guy was getting hiss and microphonics with headphones on his primaluna (wich has realcaps) , upgraded all those to good metal film oil caps, and boom, no more hiss or microphonics....

Hummm, i don't want to void my warranty though....

Just some food for thought here.