Ion Obelisk

[demons_wing]

ZETEX make excellent transistors....excellent fabrication procedure too...

[runebivrin]

Originally posted by demons_wing
what it T7 for in the first schematic?...only single ended input, but not current feedback...interesting...any idea how it works?

T7 must be the "turn on thump" blocker. T7 will conduct on startup and clamp the base of the output transistor, but as the capacitor charges, it turns off.

I'd say there's current feedback to the emitter of T3.

The gain of the initial T1/T2 stage is determined by R7 and R8.

Rune

[destroyer X]

This way, take a look at the simulator schematics, is use normal transistors, common audio units assembled inside as a switch darlington transistor. high Power Switch, may be HPS or the name Eva told us.

Do not tell anybody, but i am still using high power switch transistors in my two channels bass amplifiers.... and no big problem when hearing. But if i go to measure, i suppose i will se very strange waveforms there. This way i am not going to laboratory with those amplifiers i use for bas, i am only hearing.

Please Eva, may i know the simulator you are using?

regards all you, threaders and readers,

Carlos

[Tube_Dude]

Originally posted by runebivrin


I'd say there's current feedback to the emitter of T3.

Yes...you are right! This is current feedback!

[destroyer X]

Eva, i will inform you the program i used to increase images, focus, ligths and effects.

And you inform me the program you used to simulate circuits.

Other thing i could see.... the hand that show us components show me a very complicated line related your life. this hand line show you faced heavy obstacles and not so easy to go on without beeing strong. (for free)

My program, used to image, and now i could read the number on the picture is ACDSee last one.

The amplifier, send us by Pjoltan, from Hungary, is rated from him as a 30 Watts amplifiers, this way he used probable 8 ohms and week voltage.

Estoy feliz, hay amigos en esto mondo.

Carlos

[destroyer X]

Because AcdSee, better to See, you see.

Carlos

[Eva]

I use PSpice 6 schematics editor [win 3.11 version, pretty old but simple to use] and Orcad 9 pspice.exe to simulate and view results [since pspice.exe from PSpice 6 for win 3.11 doesn't work in win32 at all]

I also use EWB since it allows to quickly obtain bode plots for more ideal things like crossover networks or SMPS output filters

In the other hand, high power switching bipolar transistors tend to be fast and sometimes pretty linear but tend to show low current gains [10..50] and insufficient DC SOA margin for linear applications, altough <1uS pulsed SOA tends to be excelent [ie: I've seen TO-220 bipolar devices dissipating >1KW during 250ns at 2% duty cycle and still surviving, and even 5KW during 25ns]

[destroyer X]

This is good, all you say i read and think about it, sometimes a take some notes about to not forget, sometimes i save it entirelly to read again and again.

Please, continue to make those analysis... go ahead please.

Carlos

[Tyimo]

Hi!
Here are some pics of my amp. Sorry for the bad quality, but my camera is not the best.

Lohk!
I wrote: "The schematic is a version of the Ion Obelisk." It was a kit version from Heed Audio. It is a hungarian company and the owner: Zsolt Huszti is the one of the most famous audio guru in my country. They was building the Ion Obelisk in the early 90's, and afther they made a KIT from it. You could share your shcematic to us to see what is different beetween them.

Destroyer X!
Nice work you did with the simulatins! Here is the time to build one for your self! It is easy and cheap and big fun. The sound will be very musical.

Greets:

Tyimo

[Tyimo]

The front panel is made from 1,5 cm thick Granit. The paint is a kind of piano lacquer.