DISCLAIMER

DISCLAIMER: Vacuum tube circuits work with dangerously high voltages. Do not attempt to build circuits presented on this site if you do not have the required experience and skills to work with such voltages. I assume no responsibility whatsoever for any damage caused by the usage of my circuits.

All rights of photos and text reserved. Usage of photos or text from my blog on other websites or for any other purpose only with prior permission. If you want to use any material from my blog please contact me by email.



Thursday, May 30, 2013

Lundahl Silver Line Input Transformer Test

Hi!

I am an avid user of the LL7903 microphone input transformer which I like to use as line input, for example in power amps with DHT driver to get some more gain. I like this transformer for its versatility and it's very neutral and transparent sound. After the very positive experience with the silver MC step up transformers, I was glad to be able to convince Per Lundahl to issue the LL7903 as a silver version too.





I just installed a pair LL7903Ag in a 45 power amp with 10Y driver. The amp was shown in an earlier post. The copper transformers got exchanged for the silver version a few days ago. So the new silver transformers had some time to break in, since I used the amp every day. Today I finally gave it a serious listen. I have another amp with the same configuration and parts which I could use for immediate comparison.

During the first comparison a subtle but very noticeable difference was audible. The silver transformers sounded smoother yet retained all the detail. This is a property I like a lot. After listening longer time with the LL7903Ag more pronounced differences got noticeable so that it's not that subtle anymore. This power amp is already the king of tone, yet with the silver input transformers it even improved in that respect. More colours, more vibrant tone. The LL7903Ag improves over it's copper cousin in a similar way as the silver MC step up transformers.

This is not at all sounding like the common prejudices of  'silver sound'. They don't sound 'silvery' at all. It is a very beautiful, smooth, rich and extremely detailed sound.

I still did not have the time yet to try the LL1660Ag silver lineoutput / interstage transformers. If they improve in a similar way over their copper counterparts, the phonostage which I am planning with all silver transformers and silver RIAA coils will be a real treat for the ears.

Best regards

Thomas

Monday, May 27, 2013

ELROG 211 and 845 tubes now available

Hi!

The first shipment of ELROG tubes arrived today.





The tubes are nicely packaged as matched pairs. A measurement certificate signed by Dr. Schaffernicht  comes with each pair:




Each tube has it's individual serial number, stamped on a metal plate inside the glass:




Craftsmanship is exceptional. The plates always have the same alignment with regard to the pins, which is not always the case with NOS tubes.

A NOS GE211 / VT4C in comparison to a ER211:




They are about the same height. The ELROGs have a slightly larger diameter. Earlier ELROGs had a smaller diameter glass. This was changed for the final series production to give better heat dissipation. The most apparent difference is the location of the electrode system. While the system is mounted in the upper half of the tube in the GE. ELROG mounts the system close to the base, which gives  much shorter wire lengths between bins and electrodes.

I ran some measurements on a curve tracer. Comparing a NOS GE211 with ELROG. Unfortunately my tracer only allows plate voltages up to 400V.

Here is the set of plate curves of the GE:




On the X axis the scale is 50V per division. On the Y axis we have 2.5mA per division. The grid steps is 5V, starting with 0V with the left most grid line.

The ER211 in comparison:




Remember this is only up to 400V and 20mA. These curves show why these DHTs are so great. They are exceptionally linear. The ELROG is remarkably close to the GE the grid lines are a little bit steeper with the ER211 indicating slightly better transconductance.

The tubes will be tried in various amplifiers and I will provide feedback on the sound. Stay tuned!

Send an email to thomas -at- vinylsavor -dot- de for inquiries about these tubes.

Best regards

Thomas

Sunday, May 26, 2013

Interstage transformer for a 45 drives 45 amp

Hi!

With my last Lundahl shipment I received samples of a new interstage transformer, the LL2746. This is a 1+1:2+2 interstage transformer on a larger core for high current driver tubes.




The datasheet gives 45Hy primary inductance for the version gapped for 30mA. As most Lundahl transformers this one also can be ordered with different air gaps for various currents. The 30mA version seems just perfect for a 45 drives 45 power amp. With primaries as well as secondaries wired in series it will provide a 1:2 step up ratio which is very helpful since the 45 has very little gain as driver tube. This gives a 6dB boost. Of course the transformer could also be wired as 1:1 when primaries are configured in series and the secondaries in parallel. With the air gap sized for 20-25mA it would also be usable with a triode connected 46.

This interstage transformer is quite big. It comes on a larger core which is also used for small output transformers. Here a size comparison between the LL2746 and the LL1660:




I haven't tried these transformers yet. They will certainly find their way into a future 45/45 amp!

Best regards

Thomas

Monday, May 20, 2013

211 and 845 Triodes Made in Germany

Hi!

As I mentioned in my post about the High End fair in Munich this show turned into a very interesting event during the recent years. Joe Roberts is right when he says: "You never know who walks in at the fair in Munich". On one of the days at the fair, I got introduced to Dr. Schaffernicht who is one of the last (if not the very last) producers of vacuum tubes in Germany.






Dr. Schaffernicht is the owner and General Manager of the company ELROG GmbH & Co Elektronenröhren KG. As you can imagine, it was very interesting to talk to someone like this at a HiFi show. But I got really excited when I received an invitation to visit the company. Of course I didn't hesitate and accepted.




The company is in the beautiful area of Mecklenburg, about 100 km east of Hamburg. I took a flight to Hamburg and a car to get there. The area is very green with beautiful roads with trees on either side.

The ELROG facilities are in a city called Lübtheen, which is about 40km south of Schwerin, which is the closest larger city. The company is in a nice Villa in the heart of the town. ELROG used to develop and produce special purpose tubes mainly for aviation applications. For example picture tubes for head up displays or gas detector tubes. They had been very successfull in this business but demand for tubes ceased some years ago. Hence the shift to audio tubes. Dr Schaffernicht has a long history in the vacuum tube industry which spans back to the early 1960s and even late 1950s.




He started his career at Telefunken. His father was the development manager at the famous Telefunken factories in Ulm, which produced the finest tubes in the world, including such precious pieces as the EC8020. After he left Telefunken he built up and ran various businesses. Always vacuum tube related. For example developing and producing Oscilloscope tubes. With this background Dr. Schaffernicht has a vast knowledge in vacuum tube technology and has many many interesting stories to share.




This was an unique opportunity to spend two days with him and to get many insights into the tube manufacturing process and history.

The photo on the right shows the man behind the company. Dr. Klaus Schaffernicht. During my stay in Lübtheen I met him as a very nice person. I was humbled by his knowledge and willingness to share it. I am especially thankful for his hospitality and his permission to write about this visit on my blog. When ELROG decided to produce audio tubes, it was clear from the beginniung that they would not just copy GE or RCA 211s and 845s as all the others do. When Schaffernicht first looked at some old production 211 or 845 tubes he found them to be made very similar to light bulbs in the way how the electrodes are fixed within the glass and how the connections are brought to the outside. ELROG wanted to make something better and unique. Which they fully achieved, not only in the way how the tube is constructed. This becomes apparent when you see the tubes which look quite different to any other 211 or 845:






Of course they also have the thoriated tungsten filament. The plates are made of graphite like most of the old production tubes. But the plates are more massive and make a distinct solid impression. During manufacturing the tubes are evacuated through a stem at the top. After evacuation about one third of the tube surface gets flashed with a Barium getter which ensures excellent vaccum throughout the lifetime of the tube.




The dark area in the middle of the tube is a coating with graphite. Through this area an electrical connection is made between the plate and the getter. Dr. Schaffernicht hated the idea of a getter which is not at a defined potential but electrically floating as in other tubes.




The photo above shows how this contact is made. This is probably one of the reasons for the superior sound of the tubes which has been reported by users of ELROG tubes.

Assembly of the tubes is a manual and labour intensive process.



The photo above shows pre assembled triode systems. Filament and grid on the right and the plate added on the left.




As you can see, the plate is a massive structure which allows higher dissipation than the 75W which are specified for GE 211s for Class A operation. This plate can easily handle 100W.




The photo above shows the evacuation process. The tubes are mounted upside down. Evacuation takes many hours. After evacuation is complete, the tubes are sealed and the getter is flashed. This is done by a big coil and application of RF at high power. A big RF oscillator and amplifier is needed for this job. Of course it operates with tubes:




Finished tubes go through an extensive burn in process:







During the burn in the tubes are operated for 50hrs at high current. This releases remaining gases which are trapped in the graphite plates and other metals. Those gasses are captured by the getter which reacts with those gasses and binds them. This is done before the bases are mounted:





After burn a beautiful brass base is attached to the tube:




Final quality check of tubes which are finished with bases:




A comparison of a Ug/Ip curve between ELROG and General Electric, the first photo shows a NOS GE 211 / VT4C:



ELROG 211 tube:



Dr. Schaffernicht personally overlooks burn in and quality tests:






The ELROG 211 and 845 triodes have now reached a mature state and are in series production. I am pleased to announce that these tubes will become available through me shortly! Please send inquiries about ELROG tubes to thomas -at- vinylsavor -dot- de. I will make these tubes available at special introductory prices. They come with a 6 month warrantee for emission which is double the usual industry standard of 90 days and 1 year warrantee for mechanical faults. Full money back guarantee within 2 weeks from purchase in case you are not happy with the sound of the tubes!

Watch this space for updates about ELROG and new developments. This was not my last visit in Lübtheen and I am looking forward to a closer ELROG/VinylSavor cooperation. Stay tuned!

Best regards

Thomas

Saturday, May 18, 2013

Music : Edgar Froese, Macula Transfer

Hi!

This is a record which I listened to a lot when I was a teenager and it still has it's charm. Edgar Froese's album 'Macula Transfer'.





In the 1970ies there was a remarkable electronic music scene in Germany. Most commonly known is the band Kraftwerk. But there were a lot of others: Klaus Schulze, Robert Schroeder, Popol Vuh, P'cock, Jane, Novalis and also quite well known: Tangerine Dream of which Edgar Froese was a member. This is a solo album from him.

Macula Transfer was released 1976 on Brain Records. This label published much of the german electronic music of that era. This is pure 'artificial' music using all analog synthesisers and sequencers mixed with some atmospheric, heavily distorted guitars and voices. I was never very fond of Tangerine Dream, but I do like this solo album from Froese. The opening track pretty much sets the mood for the entire record. Some synth accords as opener then a rhythm based on bass guitar sets in with some atmospheric sounds. Track two is again mainly composed of very simple synth accords and guitars with an underlying sequencer rhythm which stays pretty much the same throughout the track. The rest of the album follows the same style. This music is not very sophisticated or intellectual, but fun to listen too. The atmospheric old school synth sounds go especially well with tube electronics.




I pulled out this record just recently when an old friend visited. We sat on the terrace with good cigars and drinks and played this record. It was like a blast to the past.




Best regards

Thomas

Monday, May 13, 2013

Munich High End Fair 2013

Hi!

I am back from the High End fair in Munich. This post is my very own, very short and very biased view about the show.




The High End changed considerably over the last years. Five years ago I would not have considered to visit this fair. But it got much more diverse and colorful since then. This is largely thanks to Silbatone.




The Silbatone team continued their tradition of bringing a different vintage Western Electric system to the show every year.




This year it was a Western Electric Mirrophonic Model 2.






Alternatively a pair of WE 755As was demoed




The speakers were driven by an array of Silbatone Electronics. The analog frontend was provided by Frank Schröder and Thomas Schick. Thomas brought a beautiful turntable:




The best sound of the show:




I told you this is a very biased report ;-)




The Audiaurum room with a 10Y DHT linestage, which alternatively drove a SE 6CB5A or a SE 45 amp. The source was a french CD player from Eera. The speaker is also french made. A small two way speaker with moderate 90dB sensitivity which proved sufficient even for the 1.5W 45 amp, when not played too loud.




The most beautiful piece of gear on the show:




An absolutely stunning Pagani Huayra






But who needs a sound system in such a car?






The most innovative new product:




Wolf von Langa's new speaker called Salon:




Of course based on Kilimanjaro field coil drivers. I hope to have a chance to listen to this speaker with my amps soon.




This was my very short and very biased show report. Just a few high lights. More important than the gear was the gathering with friends and meeting new people, not only at the show but also during the evenings during which we continued to listen to music at privately hosted events. Thanks to all who made this show such great fun. My photos do not do justice to that since they are too gear oriented, but I do have one nice shot with Joe Roberts of Silbatone and Jaques-Henri of Audiaurum:




Looking forward to meeting everyone again next year!

Thomas