"The End mk.4a" by KJH
With permission from the owner of the schematic "L.C.Audio Technology", and mr. G. Frederiksen, I have modified the DC-amplifier "The End". The owner accepted the circuit to be shown in public.
The reason for modification:
SMD components were used in the final version of "The End" Millennium where double-sided PCB was needed.
The modification is carried out with 2sa970 / 2sc2240, 2sa1145 / 2sc2705 (2sa1370 / 2sc3467) and 4 Sanken LAPT outputs, for all diy people that use single-sided PCB, and also done in order to achieve the erlier "high end" sound quality.
"The End mk.4a" amplifier on a piece of wood and hardwired, the first measurements came out as:
"The End mk.4a" passed 300kHz without any level loss, and very stable even with too long wires between predrivers, driver and output transistors. The mk.4a faster than 0,5ms. The rail voltage +- 37VDC and 270mA per pair of 2sa1294/2sc3263 lapt.
Next step is to get the amplifier on PCB.
The "new" modified circuit shall be published on the link below when the amplifier data is ready:
https://sites.google.com/site/httpstubeamp/home
KJH.
With permission from the owner of the schematic "L.C.Audio Technology", and mr. G. Frederiksen, I have modified the DC-amplifier "The End". The owner accepted the circuit to be shown in public.
The reason for modification:
SMD components were used in the final version of "The End" Millennium where double-sided PCB was needed.
The modification is carried out with 2sa970 / 2sc2240, 2sa1145 / 2sc2705 (2sa1370 / 2sc3467) and 4 Sanken LAPT outputs, for all diy people that use single-sided PCB, and also done in order to achieve the erlier "high end" sound quality.
"The End mk.4a" amplifier on a piece of wood and hardwired, the first measurements came out as:
"The End mk.4a" passed 300kHz without any level loss, and very stable even with too long wires between predrivers, driver and output transistors. The mk.4a faster than 0,5ms. The rail voltage +- 37VDC and 270mA per pair of 2sa1294/2sc3263 lapt.
Next step is to get the amplifier on PCB.
The "new" modified circuit shall be published on the link below when the amplifier data is ready:
https://sites.google.com/site/httpstubeamp/home
KJH.
"The End mk.4a" nov. 2015
Impossible to load JPG's here...........
The first setop:
"The End mk.4a" from nov. 2015 at Google sites
https://sites.google.com/site/httpstubeamp/home/the-end-mk-4a
KJH
Impossible to load JPG's here...........
The first setop:
"The End mk.4a" from nov. 2015 at Google sites
https://sites.google.com/site/httpstubeamp/home/the-end-mk-4a
KJH
The End mk.4a
........Found most of the semiconductors at :
https://www.reichelt.de/index.html?&ACTION=446&LA=446
Toshiba 2sa970 / 2sc2240, Toshiba 2sa1145 / 2sc2705 , Sanyo 2sa1370 / (2sc3467 out) , Sanken 2sa1294/2sc3263....
or Kessler-electronic.de :
2SA1294
Still missing 2sc3467....
Gudmund
........Found most of the semiconductors at :
https://www.reichelt.de/index.html?&ACTION=446&LA=446
Toshiba 2sa970 / 2sc2240, Toshiba 2sa1145 / 2sc2705 , Sanyo 2sa1370 / (2sc3467 out) , Sanken 2sa1294/2sc3263....
or Kessler-electronic.de :
2SA1294
Still missing 2sc3467....
Gudmund
Hi Gudmund,
I have already bought the last 30 pcs. 2SC367 from Reichelt.de....you kan have some of mine for two test PCB's, if you like
It might not be nescessery with 1145/2705...one test where the preamplifier section with 1145/2705 were changed to DC-matched 970/2240 looked very good.
So if you stay on the safe side of +-56Vdc (or may be a bit lower that that) there should be no problem with the fine Toshiba 970/2240 transistors.
So far we like the sound that much from The End mk.4a.....unfortunately there are something wrong with the HP distortion equipment, but the revised mk.4a version seems to get very close to the brilliant sound in mk.3...or better.
KJH
Checked...you are right.
Do we know anything about CDIL?....2240 manufactured in India...can we rely on that CDIL produced transistors meets the same specifications as set by Toshiba?
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