Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 29th September 2012, 02:31 PM   #1
diyAudio Member
 
h00hbt's Avatar
 
Join Date: Jun 2007
Default Visit to KR audio Prague 20120921

Hi All

I visited KR audio in Prague a week ago and thought I might share my experience with you.

Click the image to open in full size.
On the outskirts of Prague lay the remains of the giant electronic producer TESLA. Enormous old factory buildings that once housed the production of tubes in all shapes and forms. Today KR AUDIO is housed partly in these facilities and since then been producing high quality audio tubes.

Click the image to open in full size.
Welcome to the factory.

Click the image to open in full size.
On the stairway wall is the remembrance of what once was produced in these buildings presented by this figure of the TESLA telephone worke

Click the image to open in full size.
Once inside it feels like time has frozen and one gets transferred back in time to when things where made by hand and skilled craftsmanship. An open flames burning makes the room hot and one has to be aware when moving around. In this room the tube bottoms are produced and married to the tube dome once all the inner parts are connected and fastened.

Click the image to open in full size.
A skilled glass technician at work producing tube bottoms. He works from one place of the room quickly moving to the other side all the time. Better watch out for those flames…..

Click the image to open in full size.
A tube bottom is beeing heated up before pressing it into form.

Click the image to open in full size.
The pressing.

Click the image to open in full size.
Chief engineer Marek (on the left) steps in to say hello.

Click the image to open in full size.
We now move to the next production room, in fact this picture of the room comes in at an early stage because this is the storage room, also used for QC. On the left hand side is the old tube tester and burn in bench. Hiding away in the right hand corner is a modern computer based tube tester for high precision testing.

Click the image to open in full size.
Tube storage.

Click the image to open in full size.
The Marconi tube (without socket) is being scrutinized.

Click the image to open in full size.
Here´s the vintage tube testing equipment, still used today in testing.

Click the image to open in full size.
This is the modern computer based tube tester.

Click the image to open in full size.
Tubes waiting for matching.

Click the image to open in full size.
Now we move into the next production room. Here the technician is welding the tube to a glass pipe. This pipe is connected to a vacuum pump and also an oil distiller device to create the high vacuum. This is also a heating chamber to heat the tubes under vacuum.

Click the image to open in full size.

Click the image to open in full size.
Tube nr 2.

Click the image to open in full size.
All set.

Click the image to open in full size.
This picture shows the hoods slightly closed down.

Click the image to open in full size.
These machines are from the TESLA era and where used mainly for research. They are perfect for small tube production scale.

Click the image to open in full size.

Click the image to open in full size.
Oil distiller device for creating the high vacuum that KR is known for.

Click the image to open in full size.
This is what remains once the tubes are vacuumed and dislocated.

Click the image to open in full size.
On the other side of the room we find the station for producing grids. This is the old machine from the WWII era and is still used for making the grids.

Click the image to open in full size.
Grids ready for assembly.

Click the image to open in full size.
Now we step further and into the next room where the plates are produced and all internals assembled. Anode plates ready for assembly.

Click the image to open in full size.
Notice the left anode plates are not coated, the right ones are. At the bottom of the picture the press tool is present.

Click the image to open in full size.
The press for pressing out the shapes of the anode plates.

Click the image to open in full size.
This machine is for mixing the anode plate coating material.

Click the image to open in full size.
A full view of the room. At the far back of the room the assembly station is present. This is the station where the anode plates are welded and the tube internals are married together.

Click the image to open in full size.
Notice all the parts!!

Click the image to open in full size.

Click the image to open in full size.
I wouldn´t know where to start and havn´t the patience.

Click the image to open in full size.
Mascot to keep company.

Click the image to open in full size.
High tech precision industrial machine for heating lunch.

Click the image to open in full size.
This is for storing the completed tube internals before enclosing them in the glass tubes.

Click the image to open in full size.
Once the tube internals are enclosed in the glass tube, vacuumed and getters flashed it´s time for the socket mounting. This is done at the mounting station on the right.

Click the image to open in full size.
Tubes ready for mounting with sockets.

Click the image to open in full size.
This is one of the burn in stations for a 24 hour burn in cycle.

Click the image to open in full size.
KRT1610 tubes ready for shipping.

Click the image to open in full size.
On the way out with Dr Eunice Kron. Notice the TESLA technician on the wall. — with Fredrika Engvall.

It was wonderful to see the factory and I would like to thank KR for the time and dedication they took in guiding us arround. I was impressed by the craftsmanship of the people who work there have, great that tey keep the tradition alive. I am amazed that they are still getting the economy in the business when it takes up to 3 days to produce some of the tubes. I have no financial interest in the visit or posting I´m just simply a tube interested audio geek.

Cheers
__________________
/H
  Reply With Quote
Old 29th September 2012, 02:59 PM   #2
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Fascinating - thanks for sharing.
  Reply With Quote
Old 29th September 2012, 03:00 PM   #3
diyAudio Member
 
Palustris's Avatar
 
Join Date: Aug 2006
Location: Cape Cod
Thanks for the great photo essay. I will be in Prague in a few weeks and wonder if they normally welcome visitors and if they sell tubes at the factory. If so, what is the address of the factory?
  Reply With Quote
Old 29th September 2012, 03:40 PM   #4
diyAudio Member
 
h00hbt's Avatar
 
Join Date: Jun 2007
Quote:
Originally Posted by Palustris View Post
Thanks for the great photo essay. I will be in Prague in a few weeks and wonder if they normally welcome visitors and if they sell tubes at the factory. If so, what is the address of the factory?
Thank you Paulustris

All the information is on their webpage: www.kraudio.com

Prague is a fantastic city, have a nice trip.

Cheers
__________________
/H
  Reply With Quote
Old 30th September 2012, 02:53 PM   #5
dsndblm is offline dsndblm  United States
diyAudio Member
 
Join Date: Aug 2009
Thank you for sharing, very informative, well done,
  Reply With Quote
Old 30th September 2012, 03:09 PM   #6
AVWERK is offline AVWERK  United States
diyAudio Member
 
Join Date: Jan 2004
Location: OC,Calif.
Makes one appreciate the enjoyment that tubes have brought to our listening experience and the road it takes to get there!

Thank you for sharing this!

Regards
David
  Reply With Quote
Old 30th September 2012, 03:32 PM   #7
diyAudio Member
 
the_manta's Avatar
 
Join Date: Nov 2006
Location: Munich, Bavaria
What a wonderful series of photos.
Maybe I should spend them a visit. Prague isn't far.
Thank you very much.
__________________
Терпенье и труд все перетрут
  Reply With Quote
Old 25th December 2012, 07:57 AM   #8
romicap is offline romicap  Romania
diyAudio Member
 
romicap's Avatar
 
Join Date: Jan 2012
Location: Fitionesti-Vrancea
Fascinating - thanks for sharing.
  Reply With Quote
Old 25th December 2012, 08:52 AM   #9
stajo is offline stajo  Sweden
diyAudio Member
 
Join Date: Jun 2011
Location: Stockholm
Wonderful to see this genuine craftmanship still alive, or once again alive maybe. Thanks a lot for sharing.

Staffan
  Reply With Quote
Old 26th December 2012, 06:30 AM   #10
Tarzan is offline Tarzan  Belgium
diyAudio Member
 
Tarzan's Avatar
 
Join Date: May 2004
Location: Genk
A nice reminder of how tubes are made.

Here is another link that shows even more details on the fabrication of the KR tubes.
How It's Made - vacuum tubes - YouTube

Thanks for the post, h00hbt
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
KR Audio Marconi R valve amp? kenneth Tubes / Valves 2 19th August 2012 07:46 AM
KR AUDIO 842 VHD DHT Matched Pair High Power Single Ended Tube Amplifier ppereira Swap Meet 0 21st November 2011 07:29 PM
Hi from Prague jardak44 Introductions 3 2nd January 2011 07:59 PM
Audio Places to Visit in Little Rock? mikje Everything Else 0 29th December 2008 12:00 AM


New To Site? Need Help?

All times are GMT. The time now is 01:46 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2