how to make a tube gyrator eq?

Joseph R · 14th January 2010, 10:27 PM

Hi,

Does someone know a way to do a tube based gyrator eq.
I'm trying to make two different parametric tube eq.

Please look at the attached schematic file. I need to translate those opamp based eq to tubes.

Any help will be appreciate.

Thanks

SY · 14th January 2010, 11:35 PM

Take a look here:

SYclotron Audio » The Acheron: Electronic Crossover Design

Joseph R · 15th January 2010, 08:05 AM

Thanks SY

Looks interesting I will have a closer look on it later if I can adapt my circuit to yours.
Ideally I would like it to be all tube but its a good starting point.
At first I wanted to build something around Borbely's tube opamp but its too complicated and needs to much tubes.

Joseph R · 20th January 2010, 02:12 PM

Does someone have an idea for doing it all tube?

SY · 20th January 2010, 02:45 PM

Sure. In the gyrator that I show for the Acheron, the opamp is configured as a unity gain buffer. A cathode follower circuit could be substituted using a high mu, high transconductance tube

karsten21 · 20th January 2010, 09:10 PM

Hi,
well I searched a while ago for the same thing. Look here:
"http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=equal_prj.htm"
http://www.triodeel.com/images/b9b.gif

First link is a transfer of an OP-amp schematic to tube. It look nice but need double HT and nee 6 triode sytems.
The second need 10 triode systems.

I do not found any "simpler" schematic today.

But...

There is hope: I got an EQ-1 from TL Audio for repair. Unfortunately no schematic but it´s not the first time I "reenineer" a PCB to schematic

Regards
Karsten

Vix · 27th October 2010, 03:12 PM

Hi SY,

I was reading your article about the Acheron active crossover, and I liked the idea of using a gyrator. However, I couldn't figure out how to calculate gyrator values for R and C if we need different frequency (from your stated 110 Hz high-pass). More specifically, if I'd need a frequency of 150 Hz, Hi-pass, Q=0.7, with the filter sandwiched between two buffers, with input in of 100K, what values will I need to change?
( in your article: C2=10 nF C3=10nF C4=10nF, R6=120K R7=5K1 R8=200K) but I have no clue how to recalculate these values in order to come to 150 Hz...

Thanks a lot,

14th January 2010, 11:35 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Take a look here: SYclotron Audio » The Acheron: Electronic Crossover Design __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

20th January 2010, 02:45 PM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Sure. In the gyrator that I show for the Acheron, the opamp is configured as a unity gain buffer. A cathode follower circuit could be substituted using a high mu, high transconductance tube __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

20th January 2010, 09:10 PM	#6
karsten21 diyAudio Member Join Date: Jan 2010 Location: Germany	EQ only using tubes Hi, well I searched a while ago for the same thing. Look here: "http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=equal_prj.htm" http://www.triodeel.com/images/b9b.gif First link is a transfer of an OP-amp schematic to tube. It look nice but need double HT and nee 6 triode sytems. The second need 10 triode systems. I do not found any "simpler" schematic today. But... There is hope: I got an EQ-1 from TL Audio for repair. Unfortunately no schematic but it´s not the first time I "reenineer" a PCB to schematic Regards Karsten

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15th January 2010, 08:05 AM	#3
Joseph R diyAudio Member Join Date: Oct 2008	Thanks SY Looks interesting I will have a closer look on it later if I can adapt my circuit to yours. Ideally I would like it to be all tube but its a good starting point. At first I wanted to build something around Borbely's tube opamp but its too complicated and needs to much tubes.

20th January 2010, 02:12 PM	#4
Joseph R diyAudio Member Join Date: Oct 2008	Does someone have an idea for doing it all tube?

27th October 2010, 03:12 PM	#7
Vix diyAudio Member Join Date: Nov 2003 Location: Somewhere on Planet Earth	Hi SY, I was reading your article about the Acheron active crossover, and I liked the idea of using a gyrator. However, I couldn't figure out how to calculate gyrator values for R and C if we need different frequency (from your stated 110 Hz high-pass). More specifically, if I'd need a frequency of 150 Hz, Hi-pass, Q=0.7, with the filter sandwiched between two buffers, with input in of 100K, what values will I need to change? ( in your article: C2=10 nF C3=10nF C4=10nF, R6=120K R7=5K1 R8=200K) but I have no clue how to recalculate these values in order to come to 150 Hz... Thanks a lot,

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