AT-HA5000 or HA2002 are headphone amp made by Audiotechnica, Japan.
They have a lot fans, and many clone project.
However, some of the data are lost and invalid for years, I think it's time to make a review and collect what we can find on the internet.
HA5000/2002 uses UHC(Ultra High Current)-MOSFET, Hitachi 2SK2955 and 2SJ554 complementary pair, which are rated 60V/45A.
HA5000/2002 are relatively easy and safe to build, as a headphone amplifier, they don't require huge power; actually, the supply rail volt is only +-18V and you can get very decent soundstage.
There is also a clone project in 2012-2013 in Hungary if I remember right. Just call it HA2012 project. The HA2012 project is basically the same as the "traditional" clone, but it uses uPC1237 as protection which greatly reduces the complexity compared to LM393 comparator solution that Audiotechnica adopted.
Many clones claim to be 1:1, but in my experience, I don't really like the LM393 comparator protection solution: more parts, more complex, more failure rate.
As 2SK2955/2SJ554 are hard to find spice models and hence simulate the HA5000, DIYAudio member EUVL shares his LTSpice files to simulate HA5000 with other MOSFET models.
EUVL also indicated that:
I finally found some time to measure my 20 pairs of 2SK2955 / 2SJ554 bought from Japan some 10 years ago.
As you can see they are not truely complementary.
The NMOS (in red) has higher Vgs but somewhat lower Yfs (at 1.2A).
But they more or less compensate with each other if you make allowance for that in circuit design.
Extremely thermal sensitive, just like 2SK3497 / 2SJ618 so some bias control is a must.
Transconductance at 1.2A is > 10S, almost double that of the Semisouths.
If you can tame them thermally, they will drive anything.
---------------------------
Member ripson shares his curve tracing results of desoldered 2sk2955 and the comparison with 2sk1530.
---------------------------------
I uses Multisim to simulate HA5000 with good result, it runs well with VFET, MOSFET (lateral or vertical). Long time ago, I built a single-sided clone board, it was fine originally, but after years I suddenly find that it can't sing well anymore.
I have bought some genuine 2SK2955/J554 from Japan, waiting to replace the old parts which is desoldered parts, maybe it's the problem. Will keep you posted.
By the way, I also bought some cheap desoldered 2SK2955/J554 from China, and traced their curves, suprisingly they seem to be genuine K2955/J554, at least they can work normally and their curves are silimar to the genuine Japan ones.
Cheers.
They have a lot fans, and many clone project.
However, some of the data are lost and invalid for years, I think it's time to make a review and collect what we can find on the internet.
HA5000/2002 uses UHC(Ultra High Current)-MOSFET, Hitachi 2SK2955 and 2SJ554 complementary pair, which are rated 60V/45A.
HA5000/2002 are relatively easy and safe to build, as a headphone amplifier, they don't require huge power; actually, the supply rail volt is only +-18V and you can get very decent soundstage.
There is also a clone project in 2012-2013 in Hungary if I remember right. Just call it HA2012 project. The HA2012 project is basically the same as the "traditional" clone, but it uses uPC1237 as protection which greatly reduces the complexity compared to LM393 comparator solution that Audiotechnica adopted.
Many clones claim to be 1:1, but in my experience, I don't really like the LM393 comparator protection solution: more parts, more complex, more failure rate.
As 2SK2955/2SJ554 are hard to find spice models and hence simulate the HA5000, DIYAudio member EUVL shares his LTSpice files to simulate HA5000 with other MOSFET models.
EUVL also indicated that:
I finally found some time to measure my 20 pairs of 2SK2955 / 2SJ554 bought from Japan some 10 years ago.
As you can see they are not truely complementary.
The NMOS (in red) has higher Vgs but somewhat lower Yfs (at 1.2A).
But they more or less compensate with each other if you make allowance for that in circuit design.
Extremely thermal sensitive, just like 2SK3497 / 2SJ618 so some bias control is a must.
Transconductance at 1.2A is > 10S, almost double that of the Semisouths.
If you can tame them thermally, they will drive anything.
---------------------------
Member ripson shares his curve tracing results of desoldered 2sk2955 and the comparison with 2sk1530.
---------------------------------
I uses Multisim to simulate HA5000 with good result, it runs well with VFET, MOSFET (lateral or vertical). Long time ago, I built a single-sided clone board, it was fine originally, but after years I suddenly find that it can't sing well anymore.
I have bought some genuine 2SK2955/J554 from Japan, waiting to replace the old parts which is desoldered parts, maybe it's the problem. Will keep you posted.
By the way, I also bought some cheap desoldered 2SK2955/J554 from China, and traced their curves, suprisingly they seem to be genuine K2955/J554, at least they can work normally and their curves are silimar to the genuine Japan ones.
Cheers.
Attachments
The schematic and board layout of HA2012.
Very nicely done.
A) Any way to convert it into GERBER file?
B) What is the exact model of 470R thermistor?
Since UHC-MOS is highly sensitive to temp, thermistor must have adequate temp co. to compensate the change in temperature. So, what is the coefficient of thermistor?
Very nicely done.
A) Any way to convert it into GERBER file?
B) What is the exact model of 470R thermistor?
Since UHC-MOS is highly sensitive to temp, thermistor must have adequate temp co. to compensate the change in temperature. So, what is the coefficient of thermistor?
Attachments
The original is a well designed piece no doubt. Looking at their site tho i had to shake my head a bit.
AT-HA5000 Audio-Technica | Audio-Technica
Behold, the magical properties of wood.
All that good engineering and thats the marketing pitch they decided to go with?
AT-HA5000 Audio-Technica | Audio-Technica
Behold, the magical properties of wood.
All that good engineering and thats the marketing pitch they decided to go with?
Maybe I am missing something.
But what new informtion can I find here that was not in the original thread ?
AT-HA-5000 schematic
AT-HA-5000 schematic
AT-HA-5000 schematic
Cheers,
Patrick
But what new informtion can I find here that was not in the original thread ?
AT-HA-5000 schematic
AT-HA-5000 schematic
AT-HA-5000 schematic
Cheers,
Patrick
Be patient, new thing will come out, which I am working with.🙂
Also, isn't this kind of a review for new comers? Yes, there's nothing new compared to the old thread, but I read it all and digest them, then write a summary/review.
I think this lower the threashold of understanding the clone history of the community, this is what I have done. For sure, it might be nothing, for such a few pages of discussion.
For example, a few years ago I have read all post about Goldmund clone; I took note while I was reading them. For a building, it not likely to know and read evvery details that are "hidden" in the thread, e.g. how many mA that LTP consumes?, at this time, a review or summary is important, though nothing new.
I also read through the thread outside DIYA, another project called HA2012/HA2013 as shown in #3, maybe it's too less that makes you think there's nothing new, sorry for that, but I do make effort to collect info from the internet as possible.
Regards,
JH
Also, isn't this kind of a review for new comers? Yes, there's nothing new compared to the old thread, but I read it all and digest them, then write a summary/review.
I think this lower the threashold of understanding the clone history of the community, this is what I have done. For sure, it might be nothing, for such a few pages of discussion.
For example, a few years ago I have read all post about Goldmund clone; I took note while I was reading them. For a building, it not likely to know and read evvery details that are "hidden" in the thread, e.g. how many mA that LTP consumes?, at this time, a review or summary is important, though nothing new.
I also read through the thread outside DIYA, another project called HA2012/HA2013 as shown in #3, maybe it's too less that makes you think there's nothing new, sorry for that, but I do make effort to collect info from the internet as possible.
Regards,
JH
i'm new here and i'm looking for a class a amp project to drive my 600ohm cans and i thought building the clone HA5000 is a better experience than buying pre assembled i hope i can attempt to build this thing
(also if there's a better headphone amp project please let me know )
(also if there's a better headphone amp project please let me know )
What does "better" mean for you, what criteria to compare ?
For 600R phones, you do not need such power devices and high bias current.
You need higher rail voltage instead.
See for example Borbely EB602 with 24V rails with low bias :
https://audioxpress.com/article/a-battery-powered-class-a-headphone-amp
https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Borbely_Erno/Borbely_on_Line_Amps.pdf
(EB797, which is a tube version of EB602)
https://www.diyaudio.com/community/threads/the-borbely-eb602-200-revisited.325163/
or Pass HPA-1:
https://www.diyaudio.com/community/threads/pass-hpa-1-what-do-we-know.300060/
Patrick
For 600R phones, you do not need such power devices and high bias current.
You need higher rail voltage instead.
See for example Borbely EB602 with 24V rails with low bias :
https://audioxpress.com/article/a-battery-powered-class-a-headphone-amp
https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Borbely_Erno/Borbely_on_Line_Amps.pdf
(EB797, which is a tube version of EB602)
https://www.diyaudio.com/community/threads/the-borbely-eb602-200-revisited.325163/
or Pass HPA-1:
https://www.diyaudio.com/community/threads/pass-hpa-1-what-do-we-know.300060/
Patrick
i meant better as in a good reliable amp that's easier to make and sounds great
i'm very new to the diy audio and electronics world i have a little bit of knowledge about them so big projects scare me as they
involve components that can kill me if i'm not careful enough (which is true most of the time)
also thanks for the links I've found them really useful 🙂
Abe
i'm very new to the diy audio and electronics world i have a little bit of knowledge about them so big projects scare me as they
involve components that can kill me if i'm not careful enough (which is true most of the time)
also thanks for the links I've found them really useful 🙂
Abe
Then start with something simpler and where you will get help if needed :
https://diyaudiostore.com/collections/whammy-headphone-amplifier
https://diyaudiostore.com/products/acp-amp-camp-pre-amp
https://diyaudiostore.com/collectio...ir-headphone-amplifier?variant=30182425526306
Patrick
https://diyaudiostore.com/collections/whammy-headphone-amplifier
https://diyaudiostore.com/products/acp-amp-camp-pre-amp
https://diyaudiostore.com/collectio...ir-headphone-amplifier?variant=30182425526306
Patrick
Thanks again Patrick
i'm afraid i can't build those amps my country bans international payments and even if i bought the kits the costs of importing electronics here are astonishing
so i prefer making my own pcb from scratch and sourcing the electronics locally if its even possible
Abe
i'm afraid i can't build those amps my country bans international payments and even if i bought the kits the costs of importing electronics here are astonishing
so i prefer making my own pcb from scratch and sourcing the electronics locally if its even possible
Abe
Then HA5000 is definitely the wrong choice.
Component for this one is easier to source :
https://audiodesignguide.com/Headphone_amp/headphoneamp.html
Patrick
Component for this one is easier to source :
https://audiodesignguide.com/Headphone_amp/headphoneamp.html
Patrick