rock soderstrom
Tour de France
That's right, it's more like an Oliver Archut M49 for 5840 circuit. (...or lots of other cathode baised designs). Still very interesting, at least for me.
EF14 RFT + Sockets Lets see?
- Thread starter Papa Tango Charly
- Start date
Help Support GroupDIY Audio Forum:
Drosselmeier
Well-known member
Hello Drosselmeier what is the ratio of the transformer you are using in you EF13 U47 microphone thank you
Theoretically you are right, the EF13 is a remote control pentode, but the signal levels in our case are way to small to get distorted much from the unlinear characteristics of the tube. You can try the EF83 if you whish, that's a remote control pentode made for AF use...The EF13 is a fine tube, very low noise according to the data sheet. But it is a control pentode, aren't characteristic curves a bit crooked in the range where it is operated in a microphone? Maybe that's what makes this tube sound really good...
Very interesting price-wise!
Remember, EF1X are large tubes with large internal parts, they tend to be more microphonic as the innards of noval or pencil tubes, that's natural behavior.
The EF86 is a pentode made for small AF signals as we all know..but it seems to be "to normal" for microphone use that someone would use it
I would try 5840 or 5702 (5703) or something since I have a stash of those tubes, otherwise I would try E180F, EF95's or even EF80's. The latter still exists in large amounts, you can always test for the best tube regarding sound or microphonics. I personally think the characteristics of the output tranny have much more influence to the sound as the different tube types. ( yea, I already know I'm an moron..)
Regards,
Holm
Still have approx 20 new RV12P2000...
capacitorless
Well-known member
What a cool package! Makes total sense to be able to field R&R using a base-mounted knob.
rock soderstrom
Tour de France
I know a small company from Berlin, they use the EF86 in their U67 microphones.The EF86 is a pentode made for small AF signals as we all know..but it seems to be "to normal" for microphone use that someone would use it
and there's a nice guy from Denmark, he designed another tube mic around the U67.
But you are right, there are so much interesting tubes out there!
I love the 5654/E95F, I am interested in the EF37a, american steeltubes, german Poströhren, UF80 and yes, the EF13 is cool, too
cool stuff, no doubt!
...the RV12P2000? ...it was constructed in 1933 ff from Telefunken for use in military equipment. The russian 12Ж1Л (6Ж1Л, 4Ж1Л, 6Ж1П ) and 6AK5, 5654 and EF95 are direct descendants of that legendary tube build after the WW2. For microphone use I wouldn't use the socket at all, I would solderin in the tube directly since the pins and the grid cap are all soldered anyways..
Regards,
Holm
Regards,
Holm
rock soderstrom
Tour de France
Yep, I know the story. Very important tube type...
I know a small company from Berlin, they use the EF86 in their U67 microphones.
and there's a nice guy from Denmark, he designed another tube mic around the U67.
I'm talking about that what WE use, and I've wrote that this tube is to normal..
But you are right, there are so much interesting tubes out there!
I love the 5654/E95F, I am interested in the EF37a, american steeltubes, UF80 and yes, the EF13 is cool, too
cool stuff, no doubt!
Yes UF80 because of its high heater voltage of 19V, but you could always try even an UF85 or 89 for use in mic amps. As I've already wrote, the singnal level ist to small to get distorted.
Regards,
Holm
Oh yes.
Need some? kleines Röhrenchassis mit Fassungen Röhren und weiteren Bauteilen
...sorry, that's me, trying to sell old military Nato stuff, I have several boxes of that IF Amplifiers..must be from an old Radar or something (not known).
(sorry again, this isn't really an advertising, don't really want to ship that internationally...)
For all others this may be interesting, (sorry, it's german you have to translate it). There is even an very interresting EL34 story on this site:
https://www.jogis-roehrenbude.de/Roehren-Geschichtliches/P2000/P2000.htm
Regards,
Holm
rock soderstrom
Tour de France
I am also always looking for good tubes that are still affordable. The 5654/E95F is really good in this respect, hard to beat. The EF13 is still relatively cheap and available compared to the rest of the steel tube family.
rock soderstrom
Tour de France
Wow, cool! If I didn't already have such an incredible amount of stuff, I would buy this.
....I wouldn't think that you really have an "incredible amount of stuff" .. before you have seen what I have to get rid of after my retirement
BTW: If you have nothing better todo, you can meet me at 22.7.2023 in the Landhotel Kleinschirma near Freiberg in Saxony, ...not only me, but many of the tube freaks from germany. It's our 2023 meeting of old tube lovers from the "jogis-roehrenbude Forum" that existet years before. People pestering me every year to make an termin for the next meeting.. not much microphones at all but...
Regards,
Holm
BTW: If you have nothing better todo, you can meet me at 22.7.2023 in the Landhotel Kleinschirma near Freiberg in Saxony, ...not only me, but many of the tube freaks from germany. It's our 2023 meeting of old tube lovers from the "jogis-roehrenbude Forum" that existet years before. People pestering me every year to make an termin for the next meeting.. not much microphones at all but...
Regards,
Holm
rock soderstrom
Tour de France
Thanks for info!
Drosselmeier
Well-known member
Thank you
Yours sincerely
Yours sincerely
EF13 tubes needs lot of testing/burning-in, I find tube selection a bit painful.
If the tubes are ok ,they sounds fine:
If the tubes are ok ,they sounds fine:
..a little warning about chinese "Stahlröhrensockel" EF12,EF13..sockets.
The Sockets I know of are looking good, but they have one problem. They used some cheap brass contacts, If you insert a tube and pull it out again, the next one wouldn't necessarily have good contact since the contacts don't have any spring load anymore..
The tubes at aliexpress are from Röhrenwerk Mühlhausen, former GDR. (I'm too..)
Better to look for low noise types EF12K.
Regards,
Holm
The Sockets I know of are looking good, but they have one problem. They used some cheap brass contacts, If you insert a tube and pull it out again, the next one wouldn't necessarily have good contact since the contacts don't have any spring load anymore..
The tubes at aliexpress are from Röhrenwerk Mühlhausen, former GDR. (I'm too..)
Better to look for low noise types EF12K.
Regards,
Holm
I bought from ebay, and built custom tube tester with those sockets, already exchanged more than 100 times, no problem with them.
JW
Well-known member
For the EF13, in the moxtone "journey into VF14" article he shows that an operating point of about 1V seems to work well. Is the cathode resistor what we're changing to obtain this, or is it simply the exact heater voltage? I guess I don't know where to measure to find this "1V operating point" Is this the bias?
