What’s new

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03.12.2017
Transistoramp Sirrah:
The new board is testet now. The whole documentation can be downloaded as zip-file.

11.09.2017
Transistoramp Sirrah:
The new one board - low cost - great sound amplifier is online. Great performance like the Sirius with reduced output voltage. The new board is finished but not testet yet. It will be available when the tests are finished.

31.12.2016
Hybridamp Alpha Centauri:
The V6 is finished and online. It now works with EL84 in the output stage.

28.12.2016
Power Supply:

regulated power supply V5.5 with adjustable output voltages now online.

14.11.2013
Hybridamp Alpha Centauri:
The V4 is finished and online. The draft for the V3 was finished years ago, I never had the time to build one. The Sirius V4
brought new insights that justufied a new version. Now here it is. In terms of audiophile reproduction and resolution it is now on the same level as the Sirius V4.

30.06.2013
Power Supply
:
regulated power supply V4.5 with some optimizations is online. 100pF-capacitors in conjunction with a base-resistor optimizes the feedback-behavior. The electronic fuse is supplied with a higher current to the gate of the MOSFET for proper turn on. Also there are some additional protection diodes included.

28.11.2011
Transistoramp Sirius:
Version 4.0 is available now. The ultra high-end amplifier has increased current in the second and third stage and a low impedance coupling of the second stage to -400V. These changes have led to an enormous improvement of sound, especially with regard to resolution and impulse response.

22.11.2011
Power Supply
:
regulatetd power supply V4 with improved dynamic behavior is online. I used two +400V circuits instead of one +/-400V circuit to reduce the amount of different semiconductors.

10.11.2011
Transistoramplifier Sirius:
Version 4.0 will be finished soon. Support how to update from version 3.0 to 4.0 you can find here:
http://www.head-case.org/forums/topic/9916-update-transistor-amplifier-v30-to-v40-from-wwwhigh-ampde/

12.07.2011
New Side Koss ESP/950 added:
here you find some technical information about the Koss ESP/950 electrostatic headphones and a subjective judgement of sound quality

01.03.2011
Power Supply
:
regulated power supply V3 especially for transistor/hybridamp is online. The electronic fuse  is integrated. The power supply is now 100% protected against short circuits.

01.10.2010
Power Supply
:
on the site of the regulated power supply you find a circuit for an electronic fuse to upgrade existing power supplies

19.06.2010
12V switched mode power supply online:
my new power supply is finished now, the complete documentation is online available.

08.12.2009
Tips:
Short report for PADIS-Fuses added

08.10.2009
new site “old schematic versions
:
here you can find old versions of power supply and amplifier schematics

07.10.2009
Confrontation:

new field report about the hybridamp from Mr. Buchmann added

01.09.2009
Update Transistoramp:
The new transistoramplifier V3.0 is out now. Except of the possibility for offset adjustment to replace the 2SJ109 with two 2SJ74 in the input section, it has some improvements that lead to advanced sound quality. By changing the value of three resistors, the constant current source in the input section can now be supplied by either 400V or 15V.This current source and the current sources in the output section are now designed in kascade topology to improve output impedance and increase decoupling from the supply voltage.

03.05.2009
Update Hybrid-Amp:
Version V2.0 is finished. Essentially two things have changed:
The amplifier has now balanced inputs an can be connected to XLR-Connectors.
By changing the value of two resistors, the constant current source Q102 can be supplied by either 400V or 15V. The template for the layout was kindly provided by Klaus Wiczorek. He also has developed an especially for the hybridamp tailored layout for the regulated power supply, including the regulated heater voltage. It can also be downloaded here for sprint layout.
Meanwhile several amplifiers have been build, using two matched, thermical coupled 2SJ74 instead of the 2SJ109. Problems with drift did not appear.

02.07.2008
Power Supply
:
value of resistors R404,R405,R504,R505 from 1K to 1 Ohm changed.

21.05.2008
Confrontation:

new field report about the RTR400 from Mr. Dierkes added

26.04.2008
Power Supply
:
new regulated power supply with redesigned main supply and delay circuit now online. Compared to the 1. version, the output impedance is 10 times less. The reduced output impedance has a positive impact on sound. Especially the deep frequencies sound stronger and deeper.

02.04.2008
Confrontation:

new field report about the hybridamp and the transistoramp from Mr. Seyler added

08.12.2007
Tipps:
Info about the availability of the DUAL JFET 2SJ109 included.

06.10.2007
AC-Tube-Amp:
project finished now - the amp is completely online now. I’m highly pleased with the sound characteristic, no other changes were necessary.

14.07.2007
AC-Tube-Amp:
after comprehensive listening I still wasn’t satisfied completely by the sound of the amplifier and so I went back to the bench. Especially the midrange did annoy me after a long duration of listening. The result led to two changes:
- the low distortion kaskode topology in the second stage was discarded in favour of a
   better sound
- the inductionless Mundorf condensators (C4,C5) have been replaced by “simple”
  MKP-OS condensators from AUDYN-CAP in favour for a more neutral sound
 

11.06.2007
Confrontation:
new field report about the hybridamp from Mr. Lihl added

22.05.2007
Jecklin Float:
high voltage cascade to generate the BIAS voltage for Jecklin Float electrostatic headphones online

27.03.2007
AC-Tube-Amp online:
after six month designing my new amplifier, an AC coupled tubeamplifier has finished now. Schematics, layout, parts of the description and technical data and some pictures from the testing phase is available now.

05.03.2007
Confrontation:
new field report about the RTR400 from Mr. Link added

28.02.2007
New Side Jecklin Float added:
here you find some technical information about the Jecklin Float electrostatic headphones and a subjective judgement of sound quality

28.02.2007
Link added:
semiconductors at Heho Elektronik

28.02.2007
Transistor Amp:
the transistores 2SC3675 and 2SC3676 are no longer continued and are both replaced by the 2SC5466 from Toshiba. They can be ordered from Stixner+Holzinger in Munich for 0,50 Euro/piece if you order 10 pieces.

27.01.2007
Link added:
semiconductors at Strixner+Holzinger

22.01.2007
Power Supply
:
regulated powersupply with softstart for tube filament now online.

10.09.2006
Tipps:
Info about the availability of the DUAL JFET 2SJ109 included.

24.08.2006
price calculations:
price calculations for my projects online.

09.08.2006
Link added:
customised toroidal transformer at www.top-print-pcb.de

13.07.2006
 New side -Confrontation- online now. You can find there confrontations of amplifier from different designers.

04.07.2006
My Homepage is now available in english.

01.07.2006
Transistoramp:
Transistoramp with new layout and some improvements now online. The updates, I used for the hybridamp I could apply to the transistoramp too, with audible benefits to the sound. The original resistors R103, R123 have been replaced by 24V-Zenerdiodes.

08.06.2006
Power Supply:
Regulated power supply, usable for all my amps now online.

08.04.2006
Link added:
Nice little Tubeamp at www.pocnet.net

06.04.2006
Link added:
Another DIY-Tubeamp at  www.dddac.de

10.03.2006
Update Hybrid-Amp:
50K-resistor R103 replaced by 24V-Zenerdiode D104. It reduces the tendency to oscillation and has an audible benefit to sound. Mr. Maindok called me attention to this because his hybridamp had a tendency to oscillation. He placed a 10nF capasitor parallel to R103 to keep the amplifier stable.

27.11.2005
Update Hybrid-Amp:

R130 increased from 1,5K to 2,5K, Pot R131 reduced from 2K to 1K in order to reduce power dissipation of R131.

19.11.2005
RTR400:

Completely online

electrostatic principle:
Enhanced description of the electrostatic principle

14.03.2005
Hybridamp:

Completely online

10.04.2004
Transistoramp:

My first design online

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