FetZilla groupsbuy 5

[otto88]

Thanks for the update, Patrick

 

[aspringv]

Indeed!
Thanks for all your efforts mate.

 

[meanman1964]

Tomorrow visiting the post-office

 

[aspringv]

Hi Still4given - I received those LatFet's from tayda the other day. Thanks for the tip!

 

[meanman1964]

Went to the post office today,you all will recieve a mail this weekend

 

[aspringv]

Nice. Thanks again for the progress update.

 

[still4given]

Hi aspringv,

That's good to hear. I just ordered 5 more of each just to have on hand. I just finished this amp. It sounds very nice. Well worth the effort. I'm running it on a ± 38v SMPS.

Blessings, Terry

 

[meanman1964]

Are you saying Terry,you're running the FetZilla on 38Vdc?
Be carefull with that the 2sk170 doesn't like that.Set your SMPS to 35Vdc and set bias to 40mV cross R17-18

 

[still4given]

Hi Patrick,

Thanks, I didn't know that. I thought it was a 40V part. No problem, I can dial the rails down to 35V. I'm sure you can't hear a difference between 35V and 38V.

Thanks, Terry

 

[meanman1964]

How much did you set your bias?
Set it at 40mV cross R17 or 80 cross R17and R18

 

[still4given]

I followed these instructions to the tee.

Triple check all connections, switch on the amplifier one channel at a time, and adjust the quiescent to 370mA (P1), the voltage across the bootstrap resistor R12 to 24-26 volts (P3), then finally the offset to 0mV +/-10mV (P2).

Blessings, Terry

 

[meanman1964]

set it 400mA or 40mV over R17 or R18

 

[still4given]

Why so high? It sounds lovely right where it is.

 

[AndrewT]

You can measure the Vds and Vgs (almost the same when Vgs is in the mVdc range) of the FETs to see what stress is being applied.

 

[meanman1964]

Why so high? It sounds lovely right where it is.

It gives a bit more depht and when you solder a 100K resistor to PL it gives better resolution please note only when you didn't install C5.It is the 100K or C5 not both

 

[still4given]

I installed C5. Nothing in PL. I will try going higher in the Bias. If I hear a difference good. If not, I'll go back down. I want to go to smaller sinks than I'm using presently so heat may be an issue if I up the bias.

Andrew,

How do I measure the Vds and Vgs? Thanks.
Blessings, Terry

 

[AndrewT]

voltmeter
R10 to R8

 

[still4given]

Ok where do I take the measurements?

 

[AndrewT]

repost with correction of Vdg

You can measure the Vds and Vdg (almost the same when Vgs is in the mVdc range) of the FETs to see what stress is being applied.

 

[still4given]

I don't know why I bother reading your posts. They are always too technical for my understanding, and you can't seem to be bothered to put them in layman's terms.

I'm sure some of the guys who have more electronic training are helped but since I am the asking for help........................