Pardon, it is not a grid at all. Yes, it is a tetrode, the 3'rd grid had been eliminated.
Hello and comgratulations @TURING for the state of the art work!
I also build a somehow close design, starting exactly from the similitude with GU50, but willing to do a slightly better looking amplifier than the confiture jar looking of GU50's.
At the time I posted, there wasn't much about EL153, so here's the schematic I used.For the supply, I used a two windings transformer, originally intended for full wave rectification...I used instead a sillicon bridge and two pairs of electrolitics, similar to the transistor amplifiers supply, only that I used te "minus" output as ground, so I had 0->300->600V supply. It's easier to find 400-450V electrolytics and use two of them. From the 300V I obtained the 250V needed for G2, via a resistor to improve the ripple rejection and reduce the voltage accordingly to the needed 250V.
As I said in the topic from 2013, I used some 1K/50W rheostats and the real life values of the cathode resistors of EL153 are around 800 ohms, slightly larger than the LT Spice simulated value.
My design is far away from this - some hand made wooden frame, some old pc case steel plate for the chassis and the output transformers are build by @Lazaroiu, who also projected and simulated the schematic used, he is a well known electronics engineer here, helping diy-ers like me to build home made designs. The cores are scraped from old "soviet" tube television sets Rubin 102 (made in the middle 50's) - around 18mm2 core section, but non standard dimensions - the window is smaller than the conventional size - so slightly more iron than similar sized transformers.
So, here's the thread where I posted my work:
http://www.diyaudio.com/forums/tubes-valves/226554-telefunken-el153-se-circuity.html
I also build a somehow close design, starting exactly from the similitude with GU50, but willing to do a slightly better looking amplifier than the confiture jar looking of GU50's.
At the time I posted, there wasn't much about EL153, so here's the schematic I used.For the supply, I used a two windings transformer, originally intended for full wave rectification...I used instead a sillicon bridge and two pairs of electrolitics, similar to the transistor amplifiers supply, only that I used te "minus" output as ground, so I had 0->300->600V supply. It's easier to find 400-450V electrolytics and use two of them. From the 300V I obtained the 250V needed for G2, via a resistor to improve the ripple rejection and reduce the voltage accordingly to the needed 250V.
As I said in the topic from 2013, I used some 1K/50W rheostats and the real life values of the cathode resistors of EL153 are around 800 ohms, slightly larger than the LT Spice simulated value.
My design is far away from this - some hand made wooden frame, some old pc case steel plate for the chassis and the output transformers are build by @Lazaroiu, who also projected and simulated the schematic used, he is a well known electronics engineer here, helping diy-ers like me to build home made designs. The cores are scraped from old "soviet" tube television sets Rubin 102 (made in the middle 50's) - around 18mm2 core section, but non standard dimensions - the window is smaller than the conventional size - so slightly more iron than similar sized transformers.
So, here's the thread where I posted my work:
http://www.diyaudio.com/forums/tubes-valves/226554-telefunken-el153-se-circuity.html
Thanks for sharring, Carageae!
Reference the schematic posted by Lazaroiu, can you kindly explain what is that inductor and the "out" below cathode of EL 156?
Thanks A Lot.
Best Regards, Zekk.
Right! My actual transformers have separate cathode feedback windings; I'm not sure, but I think they have the same number of turns like the secondary windings, Mr. Lazaroiu can tell more about the transformers...I just used them...
The idea of using separate turns is useful if we have two separate windings - or a tap for two different output loads...in may case there's 4 and 8 ohms. Maybe it's not the same result if we use the secondary winding as feedback winding, or we have the same winding regardless the speaker load resistance...I didn't measure anything, but I'm almost certain it's the better solution using separate windings...I invite Mr. Lazaroiu to make light here if he wants to
The idea of using separate turns is useful if we have two separate windings - or a tap for two different output loads...in may case there's 4 and 8 ohms. Maybe it's not the same result if we use the secondary winding as feedback winding, or we have the same winding regardless the speaker load resistance...I didn't measure anything, but I'm almost certain it's the better solution using separate windings...I invite Mr. Lazaroiu to make light here if he wants to
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