The Very Best Amplifier I Have Ever Heard!!!!

[Junie]

Hi Fred, another best amp I can say

 

[fredlock]

You don't have any favorite?

 

[Nikos]

Ηι Junie
How many ma you adjust the bias current of transistors Exicons?
in my amp Mimesis 9.2 clone the bias current of transistors Exicons set at 145mA .

 

[Junie]

Hi Niko,

There's no adjustment, I followed the original parts list.

Junie

 

[Nikos]

Hi Niko,

There's no adjustment, I followed the original parts list.

Junie

You do not measure from the current from curiosity I say this because the difference is huge in quality if you play the transistors at 50ma per piece.

 

[Junie]

Kindly post the procedure for bias adjustment. Thanks.... But the amp sounds good to me, no smoke, no hiss, no hum.

 

[Nikos]

Kindly post the procedure for bias adjustment. Thanks.... But the amp sounds good to me, no smoke, no hiss, no hum.

I have no doubt in what you say, it is good sign of operation of your amplifier but now you should proceed in fine tune....

 

[Nikos]

Placed in series to positive or left rail your multimeter in mA .....
Take a measurment lets say for two mosfet if you take 100ma your exicons per piece at 50mA and then change your resistor bias R19 step by step to go lower or upper ,give as a post of datasheet...

 

[Junie]

Ok how to do that fine tune thingy��

 

[Nikos]

If I see well the resistance current bias R19 you use is 330Ω?

 

[Junie]

Ok, what is the ideal bias? I cannot do the measurement now. it's already morning in Dubai otherwise I will wake up my neighbor

 

[Nikos]

I told you before, my ears hear much better in 145 mΑ per peice total 435-450 mA, per rail , you will have to do the measurement, to see where you are.

 

[Junie]

Noted, i will do tomorrow.

 

[Machina]

I have 110mA per mosfet and its realy hot (above 60 degrese idle )
And i feel the difference between 50mA and 100mA. (2sk1058, 2sj162)
Nikosokey is right

 

[gaborbela]

An extra par mosfet and bigger heat sink for improvement

 

[Nikos]

:

I have 110mA per mosfet and its realy hot (above 60 degrese idle )
And i feel the difference between 50mA and 100mA. (2sk1058, 2sj162)
Nikosokey is right

 

[Nikos]

An extra par mosfet and bigger heat sink for improvement

 

[IanAS]

Hi, Could I ask please for some clarification regarding the number of MSOFETs and the quiescent current.

When you say per piece, do you mean per pair?

So 100mA, or 145mA, flowing though one pair of one 2SK and one 2SJ.

200mA, or 290mA, through two pair in parallel.

400mA, or 435 for three pairs (six devices).

Or do you mean double that current for best sound?

Thanks.

I'm just now repairing a Perreaux 9000 with a faulty 2SK176, and that is specified to be set as only 34mA per pair! (170mA total for five pairs (for each channel), yes, 20 MOSFETs in there!) I tried it at 70mA but the sinks were a bit too hot, it was intended to have forced cooling, but it's fan is far too noisy as was disabled.)

 

[koldby]

Bias is always for the pair. If 100 mA is flowing through the 2SK the same 100 mA is flowing through the complemantary 2SJ.

Koldby

 

[IanAS]

Thanks I know that but I'm trying to find out if the posts here mean that too and how much current per pair.