Zen Variations Part 2 Posted

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About that bal. aleph Zen

Maybe I'm missing somthing here, but isen't it true that when you
brigde a stereo amp to a mono amp, each halv of the amps will "see" half of the impedance of the speaker. In this case with a 4 Ohm speaker ,a balanced aleph zen would have to drive in 2 Ohm right?? sorry for my bad english :)
 
2 answers

kimarin,

Assuming both amps are driven with equal signals out of phase, then yes each amp "sees" half of the speaker load. In the case you mention, a 4 ohm speaker, each amp would see 2 ohms.

gema,

I'd call it push pull. But that is just my very humble opinion. You could call it "Fred" if you wanted! :)
 
resisors

I have maid some calculus and simulations on this new Aleph-Zen circuit. There are two things that bothers me on this circuit published as Figure 6. I can not convince the amp to ‘work properly’ if the values of resistors R6 and R15 are as written , 1K5 ohm, for 50% efficiency.

One possible solution for 50% efficiency is: R6=100 ohm and R15=150 ohm…

Please, let me now if I am wrong! I hope I am…


Regards


PS: Mr. Pass, when we can expect parts 3 and 4 ?
 
@ gema: as i understand, but i´m not shure because i´m not that shure in english, this 50% refer to the relation between current through R1 and (R13+R14) which is determinated by setting a value for R15. Is this relation necessarily same as efficiency, or how should i understand efficiency? I would take efficiency as relation of power at one moment provided at the loudspeaker to power provided by the power supply. Ok, i´ll take 1k5 now and see, i´m shure it will work.
 
:(
I think I´m getting very depressed about the resistor-value nomenclature. I even forgot to read the variations part2!

Three more questions,

does 619 for R29 in the Aleph4 mean 619R or 6190 M???? (I will leave it out then)

does 453 for R21 in the Aleph5 mean 453R or 45k?

but 221 means 220r doesn´t it?


william
 
Wuffwaff,

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I think I´m getting very depressed about the resistor-value nomenclature. I even forgot to read the variations part2!

Three more questions,

does 619 for R29 in the Aleph4 mean 619R or 6190 M???? (I will leave it out then)

does 453 for R21 in the Aleph5 mean 453R or 45k?

but 221 means 220r doesn´t it?
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In those diagrams Nelson did not use the multiplier notation. 619 for R29 is thus 619 Ohms in Aleph 4 (from the E96 series I believe) and 453 for 453 Ohms in Aleph 5 for R21. 221 is 221 Ohms and nothing else. The multiplier notation clearly states that first THREE digits is value and last is multiplier hence the components will be marked with 4 digits in Zen V2. If it is three digits only then it will be the value as stated.

NB: For low values we obviously write something else like 0R33...

As far as I know from looking at circuit diagrams for 25 years the notation Nelson started using here (which is standard marking on a lot of components though usually colour code on resistors although capacitors often are marked like this with numbers) means in short: Three digits of value with the last digit added number of zeroes at the end and hence 2210 is 221 as it is 221 plus no zero and 4752 is 47k5 as it is 475 plus 2 zeros at the end (47500 Ohms).

Hope this is clear...and that I did not mess up.

/UrSv
 
WOW!

I finished. Part 2 works.
I tested it with sophisticated little 2 Way speakers with four seasons, marillion, carmina burana, and weather report 8:30. Great!

I placed zehner diodes at the Mosfets, and it worked from the first time plugged in perfect! I hope it will do so further on, my heatsinks are 160*100*50mm, four , for each transistor one so i didn´t needed to isolate them., but its hot enough to put my coffeepot on it to hold it warm... hope transistors won´t burn.

I used the 3.3myF from the part one instead of 10myF at C4 and parallel to the powersupply capacitator. I sized down the output C1 to 4700 because of the little speakers (225mm chassis) and because others where not avaible at the moment. Every channel has its own toroid with 225W, mounted all on a piece of wood 30/40cm open without chassis or shielding, central mass at a big piece of cooper in the middle an shielded cable for input and feedback cable, hand wired , only this regulation circuits around the bipolar transistor, i used BC550C, on a small piece of prototype board, 3*4cm.
 
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