EEEngine

I think this one is the patent of EEEngine. Patent #5,347,230.
It's interesting, because classD principal is used for efficiency of rails, while the main amp still can be classAB or even classA.
The important component is in L1. The right side of L1 (150uH) is classD/square full voltage, and at the left side of L1 it is a voltage follower, following Qb to feed the output transistors Qa. Output transistors Qa is cascoded by Qb emitor voltage at low voltage, so the dissipation in Qa is small (compared to rail that is +/-90V)
If Qb's emitors are sitting at +5V, the from +5V to +90 (85V) is given by L1 from classD mechanism, efficient.

But is this schematic selfoscilating at constant frequency like UCD or not? Is this good or not?
 

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EEEngine has been in the market long enough. The patent is from 1994.
Example of current product : Yamaha PC9501 : 3000W in 8ohm bridged. And it is classAB that making 3000W with 1rack size.

Is this EEEngine do-able as a DIY project?

Anyone has schematic/service manual of Yamaha amp that uses this EEEngine?
 
I doubt we can see any Hi Fi full range performance with this kind of design. All devices have optimum performance voltage ranges. If you move the voltage out of this range, you sacrifice, performance to save power. In the low frequency region, we are not as sensitive to such amount of degradation and the power saving is probably dominating the design.
 
of course it is not for hi fi arena. this kind of amp is used for pro (read: thousands watts amps). There is no benefit using this kind of amps for your home amps since the tech is more complex than class-d.

btw some pages offer service manuals but not free, you can try googling as "eeengine service manuals". if you lucky maybe you will find full range ones. But I doubt it is worth for you who want to build by your own, too bloody, better than open ebay and you will find second hand EEEngines for 500usd.

have you ever see QSC's schematic?

quite hot in perth right now....
 

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Hi... someone send notification to me for this post 😀

This latest EEEngine G77. This is actually simplified version of Yamaha P7000s, taken very basic needs, without degrading its performance.

Regards,
Kartino

thanks Kartino for the updates ,
can i use 3pairs bjt instead of 6 pairs?


It's My Class TD Power Amplifier ������

Test Kit Power Amplifier Class TD by Delta Sound Electronics - YouTube

Class AB from G77 EEEngine High Voltage Design by Mr. Kartino Surodipo
Tracking from Labgrouppen A50TD

nice job Roby , post the pcb files