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Old 7th January 2013, 09:53 PM   #1411
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Quote:
Originally Posted by albertNL View Post
I hope someone can explain some things for me.

I have been looking at the manuals (user and service) of the A3, A30 and AJ and have made some notes of the differences. I then tried to relate the differences by comparing the amps schematics, but there are too many variables for a newcomer like me to explain the specifications. I hope you guys can give me a hand.

Rails are about the same:
A3 and A30: 25V
AJ 24V


whatever Pa was in mood to write down ; take them all as typical FW PSU , based on 2x18Vac secondaries

Gain:
A3 20dB
A30 20dB (balanced) 26dB (single ended; manual explains that A30 has 6dB greater dynamic range than A3)
AJ 19.6dB (does not specify a difference between balanced and single ended)

I understand the higher gain of the A30 is due to the input stage. Is this correct?

20db is practically same as 19,6db ; 20db means 10x , while 19,6db means 9,55x ; difference is probably result of convenient resistor values , with intention of staying in gain ballpark



Power used:
A3 and A30: Each channel draws about 100W
but:
A3 250W consumption
A30 and AJ 200W consumption

Question:
If A3 and A30 both have each channel drawing 100W, should total consumption not be similar?

again - different info originated from different places/instances where Pa wrote those numbers ; you can't expect of him to be serious all the time
channel power draw is same thing as channel power consumption
in Pa's world 50W of heat up or down is no big fuss


Active output stage biased by current source at
A3 slightly greater than 2 amps
A30 slightly less than 2 amps
AJ not given

Max. output:
A3 30W/8R, 60W/4R, 60W/2R
A30 30W/8R, 40W/4R
AJ 25W/8R, 13W/4R (Firstwatt product table)



Question:
What causes the difference between 4 Ohm output of A3 and A30? I assume it is the "slightly greater" and "slightly less" than 2A bias that is the cause. Is this assumption correct?

Question:
How come the AJ has so much lower power into 4 Ohm? I assumed that, since total power consumption is similar, bias must be similar.



ask Papa to rewrite FW product table , in case of AJ
difference between A3 and A30 - different Aleph CCS AC gain , I resume ( frankly - by memory only , lazy to compare schematics right now ........... again ....... and again ........ and again ... , same as different treshold for current clamp/limit - small bjt hidden around Rs in lower half of output stage



Max output
A3 23V 8A
A30 25V 5A
AJ 21V 2.5A

Questions:
What causes the relative large difference between A3 and A30?
Are the numbers for the AJ correct? If so, why so different from A3 and A30?


AJ - I think Pa mislead us with these 12,5W/4R ......... but frankly - I didn't looked too much in original AJ circ , regarding that issue - it was and still is irrelevant for my intentions
whatever - it's easy to make it as "usual" - Aleph having at least 30% more power on 4 , than on 8 ohm load



first , but not most important -

Thanks,

Albert
OK

time for another movie ........
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Old 7th January 2013, 09:56 PM   #1412
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laughing my ars off.
<--see
*time for another movie*
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Old 7th January 2013, 10:12 PM   #1413
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Quote:
Originally Posted by Zen Mod View Post

it's easy to make it as "usual" - Aleph having at least 30% more power on 4 , than on 8 ohm load


time for another movie ........
Before you start the DVD, can you elaborate?
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Old 7th January 2013, 10:55 PM   #1414
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use most potent one (current wise) ,as basic schm , then put your fave input (probably Jfets , cascoded or not ) , adequate number of outputs ( more pairs if spks are current hungrier) , with less intrusive current limiter

or toss it entirely - as is tossed in J2

Pa is trying all the time to give us a recepies , not 15 , OUPS - 10 ( ) God's Commandments ........

think of it as Lego ..... ya saw what he made of us , in F6 thread


http://youtu.be/4TAtRCJIqnk
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Last edited by Zen Mod; 7th January 2013 at 10:57 PM. Reason: reason why F series will go to no more than 10 , then G series
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Old 7th January 2013, 11:03 PM   #1415
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Just saw Hobbit for second time. Wha tyou wathcing? AJ is.......was easy peasy.
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Old 7th January 2013, 11:11 PM   #1416
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dunno - too much movies in folder

something funny and easy - it's 01.00 inmy neck o' wood

maybe Penelope , 2006

or Liberal Arts , 2012
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Old 7th January 2013, 11:13 PM   #1417
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Your an armchair sleeper, occasionally waking up and watching movies and answering DIy Dodos
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Old 7th January 2013, 11:18 PM   #1418
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sleeping is waste of time

btw. tomorrow was , besides Orthodox Xmass , also 70 years of Tesla's death

he was real armchair sleeper .......
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Old 7th January 2013, 11:41 PM   #1419
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Quote:
Originally Posted by Zen Mod View Post
use most potent one (current wise) ,as basic schm , then put your fave input (probably Jfets , cascoded or not ) , adequate number of outputs ( more pairs if spks are current hungrier) , with less intrusive current limiter

or toss it entirely - as is tossed in J2

Pa is trying all the time to give us a recepies , not 15 , OUPS - 10 ( ) God's Commandments ........

think of it as Lego ..... ya saw what he made of us , in F6 thread


Moses - Ten Commandments - Mel Brooks - YouTube
Thanks Zen Mod. I am afraid I have a lot of reading to do. I will return later with more specific questions.

Albert
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Old 9th January 2013, 07:19 PM   #1420
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work in progress..
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