Dear all;
I found this schematic that seem like Technics SE-A1, class AA. The site in chinese language: http://www.diyzone.net/sections.php?op=viewarticle&artid=149 .. If so, did anybody build this amp? How does it sound?
Regards:
ragil.hastomo
I found this schematic that seem like Technics SE-A1, class AA. The site in chinese language: http://www.diyzone.net/sections.php?op=viewarticle&artid=149 .. If so, did anybody build this amp? How does it sound?
Regards:
ragil.hastomo
Attachments
I have read the two articles of the link,including
http://www.diyzone.net/sections.php?op=viewarticle&artid=129
I think the project just build an amp of Leach amp units + SE-A1 topology,not clone of SE-A1.
SE-A1 topology:
Is the topology of SE-A1 similar to/same as below circuit?any comment?
http://www.ne.jp/asahi/evo/amp/2sk1380/report.htm
http://www.diyzone.net/sections.php?op=viewarticle&artid=129
I think the project just build an amp of Leach amp units + SE-A1 topology,not clone of SE-A1.
SE-A1 topology:
An externally hosted image should be here but it was not working when we last tested it.
Is the topology of SE-A1 similar to/same as below circuit?any comment?
http://www.ne.jp/asahi/evo/amp/2sk1380/report.htm
Technics SE-A1
Here is the schematic of my two SE-A1 Amps.
This is the one and only A+ Amp Matsushita ever built.
Greetings
Dieter
Here is the schematic of my two SE-A1 Amps.
This is the one and only A+ Amp Matsushita ever built.
An externally hosted image should be here but it was not working when we last tested it.
Greetings
Dieter
Speaker Connection
The speaker ist put between Ground and the terminal were the coil o/p2 at the +/- 5V Transistors are.
The signal has to pass trough the 11000µF Condensers of the power supply +/- 5V.
But no noise is heard from the speakers.
But the Amp becomes very hot, if you drive them with low level.
If you drive them with high level, it becomes colder and colder.
The current at the 5V A/A' part is 6,7A from + and 6,7A from-.
If the level grows this current shrinks.
At an Output Power of 500Watt the Amp will break down and the
Protection circuit will shut the Amp down. Also every DC overlayed Signal will bring the Amp in Protection-Modus.
This Amp is an unique piece of Amplifier and was an big desaster for the Technics-Group, because they never built one A1 and one A2 a day.
In 3 Years they only build 7 pairs af A1 and A2 which were working. The shematics they made were very mistaken, as every
A2 was built in different ways. I have two A2 (the one for Europe 220V-AC) and (the one for Australia 240V-AC) and they were built in very different ways. You cannot take one part from one and exchange to the other. The Amp will blow off!!
Greetings
Dieter from Germany
The speaker ist put between Ground and the terminal were the coil o/p2 at the +/- 5V Transistors are.
The signal has to pass trough the 11000µF Condensers of the power supply +/- 5V.
But no noise is heard from the speakers.
But the Amp becomes very hot, if you drive them with low level.
If you drive them with high level, it becomes colder and colder.
The current at the 5V A/A' part is 6,7A from + and 6,7A from-.
If the level grows this current shrinks.
At an Output Power of 500Watt the Amp will break down and the
Protection circuit will shut the Amp down. Also every DC overlayed Signal will bring the Amp in Protection-Modus.
This Amp is an unique piece of Amplifier and was an big desaster for the Technics-Group, because they never built one A1 and one A2 a day.
In 3 Years they only build 7 pairs af A1 and A2 which were working. The shematics they made were very mistaken, as every
A2 was built in different ways. I have two A2 (the one for Europe 220V-AC) and (the one for Australia 240V-AC) and they were built in very different ways. You cannot take one part from one and exchange to the other. The Amp will blow off!!
Greetings
Dieter from Germany
Hi, Technics1,
Congratulation, you have amp that is made only 7 pair in the whole world.
I still dont understand how this amp works. Maybe it works like QSC amp where the ground is modulated?
Or it works like Mr. Nelson Pass' patent (the one that is not so famous?)
Anyway, how is the sound? Is it really good?
Congratulation, you have amp that is made only 7 pair in the whole world.
I still dont understand how this amp works. Maybe it works like QSC amp where the ground is modulated?
Or it works like Mr. Nelson Pass' patent (the one that is not so famous?)
Anyway, how is the sound? Is it really good?
SE-A1 / SU-A2
There were more Amps built than the 7, which were working, but these Amps were not operating in all ways and the specifications were not held.
The price they would be sold was in germany
SE-A1 15500DM~6000US$
SU-A2 22500DM~8700US$
The SU-A2 has to be a MC Signal to noise ratio of ~120dB
The Diskcutter by direct-cut of an LP only has an S/N of max 74dB
These specs and the missing condenser in the signal-pass were only held by very good and heavy fine-tuning by technicans.
By every Amp there was an instruction book with all the diagramms of this uniqe piece. Some were hand-written and signed by the testers.
The A1 sounds very smooth and also very hard.
If the signal has peaks or cubes the output signal also has this peaks and your Loudspeaker system will give up.
The Power supply was so high (105V+ and 105V-) with an max current of 6,7A, that every loadspeaker system will break, if there comes an cubicle signal.
I have realised this too late, so one pair of SB7000 were blown off.
The SU-A2 has to be studied, before you can handle it.
The adjustings are so many, so you can make many many mistakes. i.e. to switch the Frequenzy-generator to cubic signal
greetings from germany
one day i have to sell one SE-A1 and one SU-A2, but not jet
There were more Amps built than the 7, which were working, but these Amps were not operating in all ways and the specifications were not held.
The price they would be sold was in germany
SE-A1 15500DM~6000US$
SU-A2 22500DM~8700US$
The SU-A2 has to be a MC Signal to noise ratio of ~120dB
The Diskcutter by direct-cut of an LP only has an S/N of max 74dB
These specs and the missing condenser in the signal-pass were only held by very good and heavy fine-tuning by technicans.
By every Amp there was an instruction book with all the diagramms of this uniqe piece. Some were hand-written and signed by the testers.
The A1 sounds very smooth and also very hard.
If the signal has peaks or cubes the output signal also has this peaks and your Loudspeaker system will give up.
The Power supply was so high (105V+ and 105V-) with an max current of 6,7A, that every loadspeaker system will break, if there comes an cubicle signal.
I have realised this too late, so one pair of SB7000 were blown off.
The SU-A2 has to be studied, before you can handle it.
The adjustings are so many, so you can make many many mistakes. i.e. to switch the Frequenzy-generator to cubic signal
greetings from germany
one day i have to sell one SE-A1 and one SU-A2, but not jet
Components
The components which were used to built these Amps are hand-selected.
350 Korean Guestworker have selected them between 1976 and 1979, as the management of Matsushita Co said, it makes no sense to go on building this horrable Amp.
It was a financel desaster and the guestworker were sent home.
The transformers were hand wired and capsuled by hand fitted copper cases
The cristals were boxed and signed with paper, were the data was written on by hand.
Every amp was built in a different way and the shematics I have ( Matsushita said there haven t been any shematics) were full of mistakes 
But if you have one piece playing the joy will be endless
greetings Dieter
The components which were used to built these Amps are hand-selected.
350 Korean Guestworker have selected them between 1976 and 1979, as the management of Matsushita Co said, it makes no sense to go on building this horrable Amp.
It was a financel desaster and the guestworker were sent home.
The transformers were hand wired and capsuled by hand fitted copper cases
The cristals were boxed and signed with paper, were the data was written on by hand.
Every amp was built in a different way and the shematics I have ( Matsushita said there haven t been any shematics) were full of mistakes
But if you have one piece playing the joy will be endless
greetings Dieter
![IMGDEAD]](https://www.diyaudio.com/forums/[IMGDEAD]http://i52.tinypic.com/2a0m4ap.jpg[/IMGDEAD])
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.