Live from Munich : High End 2019, Part 6

Hi!

Another premiere at this years High End is the first public demo with the newly developed Elrog ER888 tube.

The ER888 is a new tube type which never existed before.

It is the molybdenum plate cousin of the ER887.

Made to drive the ER284 output tube.

Visit us in room F231e to listen to this new tube.

Best regards

Thomas

SE 845 Mono Amplifiers

Hi!

Here some photos of newly finished single ended 845 mono amps.

Like a previous set of such amps these use a specially designed Elrog tube as driver. For this purpose we developed the ER887, of which there is now also a molybdenum plate version, the ER888.

The driver tube is on the left and instead of an 845 this amplifier gets a set of Elrog ER284, also with molybdenum plate.

The power supply uses a pair of Elrog ER274A rectifiers in conjunction with two 6AU4 TV dampers for slow ramp up of the high voltage.

 Power supply and amplifier of one channel:

Two separate heavy duty umbilicals connect between amp and PSU. One for the filaments and one for the high voltages:

The stereo set consists of 4 chassis:

The amplifier in operation:

The filaments are visible through the slotted plates.

Since these are customer amplifiers they will not been shown in Munich, but I have another set finished in different color scheme which will be on demo at the high End show next week:

Come to the High End and visit room F231e to listen to these amplifiers.


Best regards


Thomas

Amplifier Work in Progress

Hi!

A quick preview of 3 different amplifiers which are in different states of completion.

A set of 46 drive 46 amplifiers, but this time in landscape style and with Tamura output transformers.

Interstage will be a Tango.  Since they have different finishes, additional transformer covers will be placed over them. Due to the size of the Tamura it had to be mounted on a sub plate through a cut-out of the top plate.

300B mono blocks in tower chassis with 801A driver already finished, one the housing is missing.

Some pics of the internals.

And lastly a new set of ER887 drives ER845 mono blocks.

Assembly from top down.

 

Sub assembly with Output and Interstage transformer and some capacitors.

Build up of the amp, only the last level missing:

The power supply chassis is built in similar fashion.

Stay tuned for updates as these amps get finished.

Best regards

Thomas

The New 845 Mono Amplifiers

Hi!

After the introduction of the 845 amplifiers with indirectly heated driver, here are my new top of the line single ended 845 mono amps with directly heated driver.

For these amplifiers a new ELROG tube type was developed by Deutsche Elektronenröhren Manfaktur GmbH, the ER887.

Since the 845 requires a large voltage swing at it's grid an amplifier with all directly heated tubes would normally require 3 stages due to the low amplification factor of DHTs.

The ER887 is a large directly heated triode with thoriated tungsten filaments. A brand new tube type which did not exist before.

It has the same glass bottle and Jumbo 4 pin base as the 845 and runs with similar plate voltages.

It is a high mu triode with a plate resistance low enough to enable interstage transformer coupling.

Each mono amp has it's separate power supply:

Here we see one channel, PSU and amplifier:

The power supply uses a hybrid bridge with two ELROG ER274A and two 6AU4 TV dampers for the rectification of the plate voltage.

PSU and amplifier are linked with two separate heavy duty umbilicals, one for the high voltage and one for the filament voltages.

These amps got finished in April and had their debut at the High End in Munich where they were shown with some other amps.

The entire set of 4 chassis occupies a solid square meter of floor space:

This set will be shipped to Hong Kong for demo at the upcoming AV show August 10-12.

After the show they will be available for demo in the Hong Kong showroom.

Best regards

Thomas