[AnimalOnDrums]

I use it with my Audeze LCD-3. I love it. The input choice does not affect noise floor, which I don't hear anyways.

 

[Fatdoi]

Will love to hear more reviews on low impedance and efficient headphones

 

[skylinekursk]

I assume you are referring to the RCA and XLR input impedance? Never run into customer who needed this information. I need to come back to you after Chinese New Year break.

Any news on this one??

 

[skylinekursk]

have been comparing with best Russian DIY amps past weekend . Dacs are sonic frontiers sfd2mk2 and krell studio

 

[Andykong]

Any news on this one??

47 KOhm

 

[Gr3g277]

Hello guys,

I wanted to share a little tube experiment I am doing at the moment with my ha-6a.

disclaimer:
First please, this my personal experience with my amp, please do not try to reproduce what I am doing here unless you know what you are doing, and then you are doing it at your own risk
What I verified in my amp, may not hold true for yours.

SOME MORE TUBE ROLLING MADNESS :

I have some 6sn7 lying around from my Freya preamp, and knowing that the 6sn7 is one , if not the best preamp tube available, I wanted to experiment a bit....

The 6sn7 have the same electrical parameters as a 12au7. BUT, it is octal based, and draws twice the heater current, and the heaters runs only in parallel.
So... not quite the drop in replacement right ?

Right, but not too complicated either !

To use a 6sn7 in place of a 12au7, one must first know if the 12au7 are used with heater in series (12.6V) or in parallel (6.3V).
the 12au 7 is a double triode, that means, two triodes in the same tube. The 12a7 family has the heater center tap on pin 9, and heaters on pins 4&5.

To Know if the tube is used with triodes in parallel or in series, you have to look inside the amp: if pins 4 and 5 are connected and pin 9 left unconnected, that means it is wired in series so 12.6v is applied.
If pin 4&5 are wired together, and pin 9 connected as well ( center tap ) that means a parallel connection is made and the heater voltage is therefore 6.3 V.

On inspection , I have noted that MY HA-6A is wired in 6.3V !!! so that means even more tube rolling possibilities are opening !!

second disclaimer : the correct adapter (6.3V) must be used, never ever do this with a 12.6V adapter or fire will happen !
be absolutely sure you are using the correct adapter on the correct socket !

with this out of my chest :

12bh7,6sn7,6cg7,6fq7..... are possible candidates !

so just put in an adapter and all is good right ?

wait my friend not so fast !

second we have to know if the power transformer can give us enough power without burning itself trying...
the 6SN7,12bh7,6cg7,6fq7... wants 0.6A of current for it's heater.
the 12au7 wants 0.3A.

that is twice the current ! and the power and rectifier tubes still needs to be powered as well...

So how one can do this safely ?

ask the manufacturer of the amp if the power transformer is overbuilt enough to withstand the load ?

I am therefore asking Mr @Andykong : Does the power transformer of the ha6a has enough current capacity to withstand the added total load of 0.6A when used with compatible tubes ? Even better would be to know exactly what is the rated amperage on the power transformer used in the ha 6a ?


lets do some calculation here on what is the amperage consumed from the stock tubes : based on the tubes datasheets.

12au7*2 : 0.6A
kt88*2 : 3.2A
22de4*2 : 0.9A

total is 4.7 A.

putting 6sn7 in place of the 12au7 would take us to 5.3 A.
Problem is, we don't know if that is safe , as we don't know the rating from the power tranny.

But, what if we use a less current hungry power tube ? the el34 draw 1.5A per tube, so the problem is the same...
Here comes the 6l6 tube, with it's current draw of 0.9A only !

Those of you who read that thread since last year, knows that it is one of my favorite tubes in this amp
so with the 6l6 installed we have :
12au7*2 : 0.6A
6l6*2 : 1.8A
22de4*2 : 0.9A
Total : 3.3A

so know adding 0.6 A to the total for the 6sn7 tubes will get us to 3.9A only... even less than stock with the kt88 !

so here you go : ( I know It looks kinda silly.... )

I had to put an extra socket saver between the adapter and the socket, as the adapter would not fit in the small recessed cutout in the amp chassis.


So this looks like crap right... but let me tell you, Holy mama ! the sound is know nothing short than amazing !!!
The noise floor is lower, less microphonic, hiss is almost completely gone and the music is just superb.
With my utopia, which is very sensitive , the hiss can only be heard a tiny bit with the highest impedance setting.
The bass is tighter, more full bodied, soundstage is wider, highs are super smooth, music flows freely with an added sense of fluidity.

The tubes here are nothing really special, new production Tung sols 6sn7 GTB pulled from my main system Freya preamp.

I am now eager to try it with kt88 also, And waiting eagerly for @Andykong to respond

The tube preamp hierarchy is respected the 6sn7 are far better than any 12au7 Nos or new production.

Now this opens even more possibilities with that .6A heater :

the 6cg7 : a 9pin 6.3V tube ( adapter still needed ) that is basically a 6sn7 in smaller envelope. with an internal shield that reduce noise and increase separation.
the 6fq7 : Same as 6Cg7, only without the shield. A lot of great NOS options available for cheap
the 12bh7 : direct drop in replacement ! no adapter needed, only the heater at .6A as the on above.


I have some of those coming on the way.... will be reporting here

Yes I know I am crazy, In France we call it not an audiophile, but an audiopath....

see you next time fellas !

 

[Relaxasaurus]

Hello guys,

I wanted to share a little tube experiment I am doing at the moment with my ha-6a.

disclaimer:
First please, this my personal experience with my amp, please do not try to reproduce what I am doing here unless you know what you are doing, and then you are doing it at your own risk
What I verified in my amp, may not hold true for yours.

SOME MORE TUBE ROLLING MADNESS :

I have some 6sn7 lying around from my Freya preamp, and knowing that the 6sn7 is one , if not the best preamp tube available, I wanted to experiment a bit....

The 6sn7 have the same electrical parameters as a 12au7. BUT, it is octal based, and draws twice the heater current, and the heaters runs only in parallel.
So... not quite the drop in replacement right ?

Right, but not too complicated either !

To use a 6sn7 in place of a 12au7, one must first know if the 12au7 are used with heater in series (12.6V) or in parallel (6.3V).
the 12au 7 is a double triode, that means, two triodes in the same tube. The 12a7 family has the heater center tap on pin 9, and heaters on pins 4&5.



To Know if the tube is used with triodes in parallel or in series, you have to look inside the amp: if pins 4 and 5 are connected and pin 9 left unconnected, that means it is wired in series so 12.6v is applied.
If pin 4&5 are wired together, and pin 9 connected as well ( center tap ) that means a parallel connection is made and the heater voltage is therefore 6.3 V.

On inspection , I have noted that MY HA-6A is wired in 6.3V !!! so that means even more tube rolling possibilities are opening !!

second disclaimer : the correct adapter (6.3V) must be used, never ever do this with a 12.6V adapter or fire will happen !
be absolutely sure you are using the correct adapter on the correct socket !

with this out of my chest :

12bh7,6sn7,6cg7,6fq7..... are possible candidates !

so just put in an adapter and all is good right ?

wait my friend not so fast !

second we have to know if the power transformer can give us enough power without burning itself trying...
the 6SN7,12bh7,6cg7,6fq7... wants 0.6A of current for it's heater.
the 12au7 wants 0.3A.

that is twice the current ! and the power and rectifier tubes still needs to be powered as well...

So how one can do this safely ?

ask the manufacturer of the amp if the power transformer is overbuilt enough to withstand the load ?

I am therefore asking Mr @Andykong : Does the power transformer of the ha6a has enough current capacity to withstand the added total load of 0.6A when used with compatible tubes ? Even better would be to know exactly what is the rated amperage on the power transformer used in the ha 6a ?


lets do some calculation here on what is the amperage consumed from the stock tubes : based on the tubes datasheets.

12au7*2 : 0.6A
kt88*2 : 3.2A
22de4*2 : 0.9A

total is 4.7 A.

putting 6sn7 in place of the 12au7 would take us to 5.3 A.
Problem is, we don't know if that is safe , as we don't know the rating from the power tranny.

But, what if we use a less current hungry power tube ? the el34 draw 1.5A per tube, so the problem is the same...
Here comes the 6l6 tube, with it's current draw of 0.9A only !

Those of you who read that thread since last year, knows that it is one of my favorite tubes in this amp
so with the 6l6 installed we have :
12au7*2 : 0.6A
6l6*2 : 1.8A
22de4*2 : 0.9A
Total : 3.3A

so know adding 0.6 A to the total for the 6sn7 tubes will get us to 3.9A only... even less than stock with the kt88 !

so here you go : ( I know It looks kinda silly.... )



I had to put an extra socket saver between the adapter and the socket, as the adapter would not fit in the small recessed cutout in the amp chassis.


So this looks like crap right... but let me tell you, Holy mama ! the sound is know nothing short than amazing !!!
The noise floor is lower, less microphonic, hiss is almost completely gone and the music is just superb.
With my utopia, which is very sensitive , the hiss can only be heard a tiny bit with the highest impedance setting.
The bass is tighter, more full bodied, soundstage is wider, highs are super smooth, music flows freely with an added sense of fluidity.

The tubes here are nothing really special, new production Tung sols 6sn7 GTB pulled from my main system Freya preamp.

I am now eager to try it with kt88 also, And waiting eagerly for @Andykong to respond

The tube preamp hierarchy is respected the 6sn7 are far better than any 12au7 Nos or new production.

Now this opens even more possibilities with that .6A heater :

the 6cg7 : a 9pin 6.3V tube ( adapter still needed ) that is basically a 6sn7 in smaller envelope. with an internal shield that reduce noise and increase separation.
the 6fq7 : Same as 6Cg7, only without the shield. A lot of great NOS options available for cheap
the 12bh7 : direct drop in replacement ! no adapter needed, only the heater at .6A as the on above.


I have some of those coming on the way.... will be reporting here

Yes I know I am crazy, In France we call it not an audiophile, but an audiopath....

see you next time fellas !

Uhh are you selling adapters? This is amazing!

I have some 6sn7 -> KT88 adapters for my Euforia and I love the results. I can only imagine how a quality 6ns7 sounds on the HA-6A. Great work!!

 

[kimdeug]

Hello guys,

I wanted to share a little tube experiment I am doing at the moment with my ha-6a.

disclaimer:
First please, this my personal experience with my amp, please do not try to reproduce what I am doing here unless you know what you are doing, and then you are doing it at your own risk
What I verified in my amp, may not hold true for yours.

SOME MORE TUBE ROLLING MADNESS :

I have some 6sn7 lying around from my Freya preamp, and knowing that the 6sn7 is one , if not the best preamp tube available, I wanted to experiment a bit....

The 6sn7 have the same electrical parameters as a 12au7. BUT, it is octal based, and draws twice the heater current, and the heaters runs only in parallel.
So... not quite the drop in replacement right ?

Right, but not too complicated either !

To use a 6sn7 in place of a 12au7, one must first know if the 12au7 are used with heater in series (12.6V) or in parallel (6.3V).
the 12au 7 is a double triode, that means, two triodes in the same tube. The 12a7 family has the heater center tap on pin 9, and heaters on pins 4&5.



To Know if the tube is used with triodes in parallel or in series, you have to look inside the amp: if pins 4 and 5 are connected and pin 9 left unconnected, that means it is wired in series so 12.6v is applied.
If pin 4&5 are wired together, and pin 9 connected as well ( center tap ) that means a parallel connection is made and the heater voltage is therefore 6.3 V.

On inspection , I have noted that MY HA-6A is wired in 6.3V !!! so that means even more tube rolling possibilities are opening !!

second disclaimer : the correct adapter (6.3V) must be used, never ever do this with a 12.6V adapter or fire will happen !
be absolutely sure you are using the correct adapter on the correct socket !

with this out of my chest :

12bh7,6sn7,6cg7,6fq7..... are possible candidates !

so just put in an adapter and all is good right ?

wait my friend not so fast !

second we have to know if the power transformer can give us enough power without burning itself trying...
the 6SN7,12bh7,6cg7,6fq7... wants 0.6A of current for it's heater.
the 12au7 wants 0.3A.

that is twice the current ! and the power and rectifier tubes still needs to be powered as well...

So how one can do this safely ?

ask the manufacturer of the amp if the power transformer is overbuilt enough to withstand the load ?

I am therefore asking Mr @Andykong : Does the power transformer of the ha6a has enough current capacity to withstand the added total load of 0.6A when used with compatible tubes ? Even better would be to know exactly what is the rated amperage on the power transformer used in the ha 6a ?


lets do some calculation here on what is the amperage consumed from the stock tubes : based on the tubes datasheets.

12au7*2 : 0.6A
kt88*2 : 3.2A
22de4*2 : 0.9A

total is 4.7 A.

putting 6sn7 in place of the 12au7 would take us to 5.3 A.
Problem is, we don't know if that is safe , as we don't know the rating from the power tranny.

But, what if we use a less current hungry power tube ? the el34 draw 1.5A per tube, so the problem is the same...
Here comes the 6l6 tube, with it's current draw of 0.9A only !

Those of you who read that thread since last year, knows that it is one of my favorite tubes in this amp
so with the 6l6 installed we have :
12au7*2 : 0.6A
6l6*2 : 1.8A
22de4*2 : 0.9A
Total : 3.3A

so know adding 0.6 A to the total for the 6sn7 tubes will get us to 3.9A only... even less than stock with the kt88 !

so here you go : ( I know It looks kinda silly.... )



I had to put an extra socket saver between the adapter and the socket, as the adapter would not fit in the small recessed cutout in the amp chassis.


So this looks like crap right... but let me tell you, Holy mama ! the sound is know nothing short than amazing !!!
The noise floor is lower, less microphonic, hiss is almost completely gone and the music is just superb.
With my utopia, which is very sensitive , the hiss can only be heard a tiny bit with the highest impedance setting.
The bass is tighter, more full bodied, soundstage is wider, highs are super smooth, music flows freely with an added sense of fluidity.

The tubes here are nothing really special, new production Tung sols 6sn7 GTB pulled from my main system Freya preamp.

I am now eager to try it with kt88 also, And waiting eagerly for @Andykong to respond

The tube preamp hierarchy is respected the 6sn7 are far better than any 12au7 Nos or new production.

Now this opens even more possibilities with that .6A heater :

the 6cg7 : a 9pin 6.3V tube ( adapter still needed ) that is basically a 6sn7 in smaller envelope. with an internal shield that reduce noise and increase separation.
the 6fq7 : Same as 6Cg7, only without the shield. A lot of great NOS options available for cheap
the 12bh7 : direct drop in replacement ! no adapter needed, only the heater at .6A as the on above.


I have some of those coming on the way.... will be reporting here

Yes I know I am crazy, In France we call it not an audiophile, but an audiopath....

see you next time

Thanks a lot.

Thanks a lot from New Zealand.

Absolutely amazing job has been done with a lot of research and thoughts.
Highly appreciated your time and efforts.
I new you will do it, when I saw the question about 6.3V or 12.6V for 12AU7.
I also prefer 6SN7 tube sound more than 12AU7.
Currently I try to make aluminium ring/socket saver for 12AU7 tubes, just for aesthetic view and elevate 12AU7 little bit up.
Similar aluminium ring like around the KT88/EL34 socket.
With this Covid situation it is a big delay of worldwide delivery for my tubes orders.
Half already arrived, but another half still on the way (3 months).

Keep Rolling!
Regards,
Kim

 

[Gr3g277]

Uhh are you selling adapters? This is amazing!

I have some 6sn7 -> KT88 adapters for my Euforia and I love the results. I can only imagine how a quality 6ns7 sounds on the HA-6A. Great work!!

Guys please if you want to try this do it only wirh 6l6 tubes on the power.
Unfortunately i couldnt check the rating of the power transformer on inspection.

So unless cayin says that the power tranny has enough headroom, i would advise against doing it...

6sn7 to kt88 adapter ???? Never heard of that ! Is it any good ?

Thanks a lot from New Zealand.

Absolutely amazing job has been done with a lot of research and thoughts.
Highly appreciated your time and efforts.
I new you will do it, when I saw the question about 6.3V or 12.6V for 12AU7.
I also prefer 6SN7 tube sound more than 12AU7.
Currently I try to make aluminium ring/socket saver for 12AU7 tubes, just for aesthetic view and elevate 12AU7 little bit up.
Similar aluminium ring like around the KT88/EL34 socket.
With this Covid situation it is a big delay of worldwide delivery for my tubes orders.
Half already arrived, but another half still on the way (3 months).

Keep Rolling!
Regards,
Kim

Thank you my friend !

I love the 6sn7, it is an amazing tube !
Looking forward to your experiment !

 

[Gr3g277]

For those you want to know here is the adapters I used

https://a.aliexpress.com/_mrUwWRV

Socket savers are pretty easy to find !

 

[Andykong]

Hello guys,

I wanted to share a little tube experiment I am doing at the moment with my ha-6a.

disclaimer:
First please, this my personal experience with my amp, please do not try to reproduce what I am doing here unless you know what you are doing, and then you are doing it at your own risk
What I verified in my amp, may not hold true for yours.

SOME MORE TUBE ROLLING MADNESS :

I have some 6sn7 lying around from my Freya preamp, and knowing that the 6sn7 is one , if not the best preamp tube available, I wanted to experiment a bit....

The 6sn7 have the same electrical parameters as a 12au7. BUT, it is octal based, and draws twice the heater current, and the heaters runs only in parallel.
So... not quite the drop in replacement right ?

Right, but not too complicated either !

To use a 6sn7 in place of a 12au7, one must first know if the 12au7 are used with heater in series (12.6V) or in parallel (6.3V).
the 12au 7 is a double triode, that means, two triodes in the same tube. The 12a7 family has the heater center tap on pin 9, and heaters on pins 4&5.



To Know if the tube is used with triodes in parallel or in series, you have to look inside the amp: if pins 4 and 5 are connected and pin 9 left unconnected, that means it is wired in series so 12.6v is applied.
If pin 4&5 are wired together, and pin 9 connected as well ( center tap ) that means a parallel connection is made and the heater voltage is therefore 6.3 V.

On inspection , I have noted that MY HA-6A is wired in 6.3V !!! so that means even more tube rolling possibilities are opening !!

second disclaimer : the correct adapter (6.3V) must be used, never ever do this with a 12.6V adapter or fire will happen !
be absolutely sure you are using the correct adapter on the correct socket !

with this out of my chest :

12bh7,6sn7,6cg7,6fq7..... are possible candidates !

so just put in an adapter and all is good right ?

wait my friend not so fast !

second we have to know if the power transformer can give us enough power without burning itself trying...
the 6SN7,12bh7,6cg7,6fq7... wants 0.6A of current for it's heater.
the 12au7 wants 0.3A.

that is twice the current ! and the power and rectifier tubes still needs to be powered as well...

So how one can do this safely ?

ask the manufacturer of the amp if the power transformer is overbuilt enough to withstand the load ?

I am therefore asking Mr @Andykong : Does the power transformer of the ha6a has enough current capacity to withstand the added total load of 0.6A when used with compatible tubes ? Even better would be to know exactly what is the rated amperage on the power transformer used in the ha 6a ?

Spoiler

lets do some calculation here on what is the amperage consumed from the stock tubes : based on the tubes datasheets.

12au7*2 : 0.6A
kt88*2 : 3.2A
22de4*2 : 0.9A

total is 4.7 A.

putting 6sn7 in place of the 12au7 would take us to 5.3 A.
Problem is, we don't know if that is safe , as we don't know the rating from the power tranny.

But, what if we use a less current hungry power tube ? the el34 draw 1.5A per tube, so the problem is the same...
Here comes the 6l6 tube, with it's current draw of 0.9A only !

Those of you who read that thread since last year, knows that it is one of my favorite tubes in this amp
so with the 6l6 installed we have :
12au7*2 : 0.6A
6l6*2 : 1.8A
22de4*2 : 0.9A
Total : 3.3A

so know adding 0.6 A to the total for the 6sn7 tubes will get us to 3.9A only... even less than stock with the kt88 !

so here you go : ( I know It looks kinda silly.... )



I had to put an extra socket saver between the adapter and the socket, as the adapter would not fit in the small recessed cutout in the amp chassis.


So this looks like crap right... but let me tell you, Holy mama ! the sound is know nothing short than amazing !!!
The noise floor is lower, less microphonic, hiss is almost completely gone and the music is just superb.
With my utopia, which is very sensitive , the hiss can only be heard a tiny bit with the highest impedance setting.
The bass is tighter, more full bodied, soundstage is wider, highs are super smooth, music flows freely with an added sense of fluidity.

The tubes here are nothing really special, new production Tung sols 6sn7 GTB pulled from my main system Freya preamp.

I am now eager to try it with kt88 also, And waiting eagerly for @Andykong to respond

Spoiler

The tube preamp hierarchy is respected the 6sn7 are far better than any 12au7 Nos or new production.

Now this opens even more possibilities with that .6A heater :

the 6cg7 : a 9pin 6.3V tube ( adapter still needed ) that is basically a 6sn7 in smaller envelope. with an internal shield that reduce noise and increase separation.
the 6fq7 : Same as 6Cg7, only without the shield. A lot of great NOS options available for cheap
the 12bh7 : direct drop in replacement ! no adapter needed, only the heater at .6A as the on above.


I have some of those coming on the way.... will be reporting here

Yes I know I am crazy, In France we call it not an audiophile, but an audiopath....

see you next time fellas !

I sincerely appreciate your effort to expand the tube rolling possibilities with HA-6A, I am sure all audiophile will understand the effort and dedication behind this sharing.

However, what you did is a very high risk option, it goes against the tube replacement advice we stated in the user manual, and is therefore considered abuse application from warranty point of view. Under this circumstances, there is no way I can endorse or contribute to your work directly. The worst case scenario, someone run into trouble and toasted his amplifier, and then he ask his dealer for warranty because "Andy Kong provided the information for this". The tough part is, my dealer in Thailand or Japan (for example) cannot turn down customer request by quoting your disclaimer, they probably unaware of your disclaimer to start with.

 

[Gr3g277]

hello andykong,

I appreciate your answer, and totally understand your point of view.
My Ha-6a is past it's warranty date of 1year, so yes I personally took the risk to try it for myself.

I also made big disclaimers and was particularly clear that doing so has it's own risks and that any person attempting to do it accepts the risk of voiding the warranty, and that the manufacturer, you, myself, or the head-fi forum can't be hold responsible for any damage that may occur.

In life I am an It systems engineer working as consultant for big companies, I have education in electronics, and used to repair electronic cards, so I have some background... my post above is only for recreational/educational purpose

In the future I will post other disclaimers of the sort If I happen to do some more experiments with my amp

I will understand if you are therefore not willing to answer my question about the Amperage rating of the power transformer....

Tube rolling in this amp is just too much fun, and I think that as educated adults, we can share our fun experiments together. I firmly believe that this what this forum is all about

 

[skylinekursk]

Hello Gentlemen! Thanks for sharing tube rolling experience!
what is most fatty sounding tube for ha6a?

 

[kimdeug]

I sincerely appreciate your effort to expand the tube rolling possibilities with HA-6A, I am sure all audiophile will understand the effort and dedication behind this sharing.

However, what you did is a very high risk option, it goes against the tube replacement advice we stated in the user manual, and is therefore considered abuse application from warranty point of view. Under this circumstances, there is no way I can endorse or contribute to your work directly. The worst case scenario, someone run into trouble and toasted his amplifier, and then he ask his dealer for warranty because "Andy Kong provided the information for this". The tough part is, my dealer in Thailand (for example) cannot turn him down by quoting your disclaimer.

Hello Gentlemen! Thanks for sharing tube rolling experience!
what is most fatty sounding tube for ha6a?

I have found that included Genalex Gold Lion (Russian) are very good. Genalex Gold Lion (made in England) and KT88 GEC may be 10% fatty/Juicer in sound, but with price 20 times more. NOS 6550 Coke bottle shape (Tungsol, RCA, Sylvania) will be smooth and creamy too. But again. I prefer KT88 sound. Have ordered KT88-T Psvan MK II and JJ KT88. As I said before, the power tube range is quite limited, So I am more concentrated on 12AU7 rolling as the range is huge.

Regards,
Kim

 

[ThanatosVI]

I have found that included Genalex Gold Lion (Russian) are very good. Genalex Gold Lion (made in England) and KT88 GEC may be 10% fatty/Juicer in sound, but with price 20 times more. NOS 6550 Coke bottle shape (Tungsol, RCA, Sylvania) will be smooth and creamy too. But again. I prefer KT88 sound. Have ordered KT88-T Psvan MK II and JJ KT88. As I said before, the power tube range is quite limited, So I am more concentrated on 12AU7 rolling as the range is huge.

Regards,
Kim

Well there are also the
TaD KT88-STR blackplates
KR KT88
EAT KT88

Those 3 received plenty of praise, however at a higher price than Gold lions.

12au7 rolling is considerably cheaper