Recent content by geoffgjones

Sorry for not being around. 1. a negative version will be posted ASAP. 2. David: Q2 Vbe has some but very little effect, the voltage output being a little under the zener's voltage. The output current should, however, always be above a few (5 or 6) mA to ensure regulation (the Hfe of Q1...

error! error! that should say 2 volts. getting rusty already:p

Yes the little gyrator has been tried on many an amp, including some early sharp, sony and marantz offerings. Try it yourself. Make sure the input V is at least 4v greater then the output. Any noise can be reduced further by using a better device than the zener, but not by much! Cheers, Geoff

Good God people, keep your hats on and your knickers up:p! I worked in the electronics industry as a designer for 20 years. Most of my ideas were ripped off within a few months:mad:! If Teddy thinks he has done something new with his pie filter and filtered gyrator he his off his rocker:o. Very...

Have now tried this against a teddy Reg MKII and can confirm that the loss of the lm317 makes this circuit shine! A good (but not special) cap for C1 makes a difference. It can also be reduced to 47uF without loss of smoothing. I am extreeeeeemely happy with this circuit, and hope to know what...

Hi all, Here is a plan for a strip board layout. http://www.box.net/shared/da5i11gr11 regards, Geoff

Hi Randy, Will post a negative version ASAP. The voltage should be between 1.4 and 2 volts lower than the zener voltage. Will get back to you soon, busy weekend so far! Cheers, Geoff

Hi Randy, The output voltage under load should be very stiff, expect +/- 0.5 variation only. the charge time is also very short, as the JFET works as a constant current supply, and charges the cap very fast as long as your input voltage is a handfull of volts over the required output voltage...

Hi Randy, The regs I am using are withing my PM17KI, and buried somewhat. I am going to make a few more PCBs to power my CD5x over the weekend, so I will take some pics then. The sound is rather similar to the teddyreg, but with a slightly clearer top end, but slightly leaner lower end...

Hi Flashgo, The ubiquitous D44H11 will do nicely, although I have had good results with the MJE520. Any low noise devices will be OK for the other transistors, including BC547C and J112 for the Jfet. Experimentation is easy with this circuit! I think that the loss of the LM317T gives the...

72 views and no comments? Please try this simple circuit, I have it running the voltage gain stage (43 volts) on my PM17KI (a model I was involved with professionally). I have also tried it in my CD63KI for powering the opamps with great effect, better than anything else yet! Cheers, Geoff

This is a simple version of the gyrator circuit that many people are using for thier cd players and pre-amps. It does not require a pre-regulator, as the zener maintains a stable voltage at the output. Further, it can be used for power applications as well, with almost any input / output voltage...