An illustrated guide for Aleph 60 builders

[Danger Mouse]

short copy & paste orgy

i think about this

but will it work

 

[Danger Mouse]

Jfet input stage at aleph 60 is plan B, if irfp9610 at input dosn`t meet my taste.
Then JFet input known and loved from the AlephJ will be an alterantive

But Jfets must survive ca. 36V rails

 

[PKI]

Try MOSFETs first I still miss that amp sometimes!

 

[Zen Mod]

short copy & paste orgy

i think about this

but will it work

it will !!

as speaker welder

 

[PKI]

For a second I was thinking: "speaker welder" what the heck it is... Some sort of mu-follower or something... So funny!

 

[Danger Mouse]

Try MOSFETs first I still miss that amp sometimes!

Why, whats happend to yours?

 

[PKI]

Life is a constant motion. You either move or done .

Just kidding(actually not), I wish I had money and space to keep them all

 

[Danger Mouse]

To small sinks? I dont know? my calc was this way

2.22A bias with+/- 35V rails will be 155,4W per channel, +20% margin for all the other stuff makes 186,6W for one sink which have with 200mm min. 0,125 K/W maybe 0,1K/W

So the temp rise will be 23,31°C with 35°C room temp i will have 58°C Sink Temp.

so all seems fine and i have 20% margin in my calc, some i will need for rectifiers and the rest of the chassis will also dissipate heat.

so i think it should work-> or did i make a mistake and this all will not work? ...dont drive me crazy

and my question with the CRC vs C thing...
....my intend was this way i dont see any CRC at the org. A60 SM, at the first view no CRC at the actual XA30.5 and this all are
highly praised amps with only C PSU`s. and this makes me thinking...

you not...

 

[Danger Mouse]

ticktock. whats the hight of your sinks? and what is the sink temp on your aleph J?

not ticktock but me

with 150mm sinks the aleph J works at 44° at my home

 

[AudioSan]

Aleph J at 44c with say 22c ambient = 22/75=0.29C/W that is pretty far from 0.1C/W.
to get aleph 60 at the same temp, you need 0.14C/W pr ch.
even with 30c above ambient you will need 0.19C/W

 

[Danger Mouse]

the J with 2 amps an +-24V rails have 96W per channel

what the 75 by you?

 

[AudioSan]

oh, then we are down to 0.23C/W

 

[Danger Mouse]

...and say it was a hot day with 27° ambient then we are at 0,177K/W

ok i know what you want to tell me.

 

[AudioSan]

but why 2amps bias on the aleph J? orignal it is around 1.7A right?

 

[PKI]

I had two 210x300mm heatsinks from modushop per channel. Each rated at 0.2k/w

 

[PKI]

when I was biasing AJ at 2A it was much hotter than one channel of A60 on the same sinks.

 

[AudioSan]

that is just not possible. rails * bias = aleph 60 is hotter.
+/-23-24V rails and 2A bias =92-96W (alephJ)
+/-35V rails and 2.2A bias =154W (aleph 60)

or did you meen one ch aleph 60 on the same sinks as 2 ch aleph J?

 

[PKI]

Oh, that was not correct what I sad. The fet temperature! That what I am worrying about now. Due to the lower dissipation/device. Dissipation of A60 was no doubt bigger, although I biased it a bit lower and rails were 32V.

 

[Danger Mouse]

but why 2amps bias on the aleph J? orignal it is around 1.7A right?

In schematics it is nothing written down, from where do you know thats it 1,7A?