Jadis PA 100 amp - Jadis becomes Jadis again

[jadis]

Stay safe and to our WBF members as well

You too, Doc. As we all know, doctors like yourself are our modern day heroes in fighting this pandemic.

 

[tdh888]

Thanks Phillip

 

[mullard88]

Take care Doc. I hope to meet you, not professionally, after this corona virus quarantine is over.

 

[tdh888]

Thank you Mullard , stay safe as well .

 

[JackD201]

Congratulations Phil! That looks like a beauty!

Hi Sam! Miss you neighbor !

 

[jadis]

Congratulations Phil! That looks like a beauty!

Hi Sam! Miss you neighbor !

Thanks Buddy. Miss our bearhugs, LOL. Well, we have to invent a contactless bearhug without looking silly.

 

[JackD201]

The elbow bump is the new normal

 

[jadis]

The elbow bump is the new normal

Right.

 

[mullard88]

Miss you too Jack. You're another one I look forward to getting together with after this quarantine is over.

 

[JackD201]

I've been in Binangonan for almost a month now. Separation anxiety from my main system hahahaha I have Unifield 2s, an Aurender, an EERA DAC and an old LSA Statement Integrated to keep me sane hahahaha

Let's listen to the excellent LP Gian sent me through you when this is all over

Need to get you a power cord Phil

 

[milesdavis1943]

Hi,

It is auto bias. I had to verify it at the dealer's by asking them to open up the bottom plate for me to see if there are manual bias pots, and there were none. Also beside each power tube socket is a small red LED indicator. If it lights up, time to change the power tubes, and I was told that even its other partner has to be changed even thought its LED did not light up.

 

[milesdavis1943]

THANKS FOR YOUR REPLY

 

[musicfirst1]

Nice point to point wiring . I think the predecessor the DA/Defy 7 had a circuit board but am not sure . Enjoy it in good health Phillip .

I owned the Defy 7, and yes it did indeed have a circuit board and had to be manually biased in groups of 3 power tubes. A pain to maintain and bias, but sublime sound.

 

[milesdavis1943]

IS THE JADIS PA-100 AUTO BIAS OR DO YOU HAVE TP REMOVE THE BOTTOM PLATE TO BIAS TUBES?

Are you sure? The JADIS sales person said you must remove bottom plate like the DA-7 TO BIAS TUBES.

 

[AudioLibertarian]

Any definite answer on the type of bias in the PA 100? On the Jadis web site it says MANUAL ... Would GREATLY appreciate the feedback!

 

[AudioLibertarian]

Hi,

It is auto bias. I had to verify it at the dealer's by asking them to open up the bottom plate for me to see if there are manual bias pots, and there were none. Also beside each power tube socket is a small red LED indicator. If it lights up, time to change the power tubes, and I was told that even its other partner has to be changed even thought its LED did not light up.

Hi,

Has it been definitive that the bias is automatic? teh site says the bias is manual in capital letters. Also any update how reliable the amplifier has been and how it sounds after awhile?

Please advise. THANKS!

 

[jadis]

Hi,

Has it been definitive that the bias is automatic? teh site says the bias is manual in capital letters. Also any update how reliable the amplifier has been and how it sounds after awhile?

Please advise. THANKS!

To me, manual bias means there will be biasing POTS. So you can adjust and set it with a digital voltmeter. The PA100 does not have any pots at all. So it CANNOT be manual. There is nothing for you to calibrate on when you change tubes. Just make sure they are Matched pair or matched sextets, etc. So far, after 3 years, a few fuse snapped and it was like a voltage surge. Change the 160mA fuse and ready to go again. Of course, after 2000 hours, life begins to shorten for the KT88 tubes. That is where I am now.

 

[jadis]

Any definite answer on the type of bias in the PA 100? On the Jadis web site it says MANUAL ... Would GREATLY appreciate the feedback!

I believe there is a misprint on the manual and all dealers copy it, as Manual. The biasing system is push pull which is the same as my old Jadis JA 200 class A amp, and also the same as the JA120 amp, and the indication of these 2 amps is called Automatic Bias. A clear misprint of the PA100, if you ask me.

 

[jadis]

Here is an actual photo I took of the underchassis of the PA100. It was a demo amp in the showroom and I asked to check the innards to make sure if there are biasing POTs or not. I wanted to see there were none before I bought it. So there was none whatsoever. So how can anyone call that Manual biasing? How do you do it? Where?
No pots to stick the voltmeter in, and no adjustment trim pots either.

 

[jadis]

No pots or trimmers either from the top chassis.