Jadis PA 100 amp - Jadis becomes Jadis again

jadis

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines
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.
 
  • Like
Reactions: Scott Naylor

tdh888

Well-Known Member
Nov 4, 2010
298
28
935
Philippines
Thanks Phillip
 
  • Like
Reactions: jadis

mullard88

Well-Known Member
Jun 5, 2010
948
62
1,588
Take care Doc. I hope to meet you, not professionally, after this corona virus quarantine is over.
 

tdh888

Well-Known Member
Nov 4, 2010
298
28
935
Philippines
Thank you Mullard , stay safe as well .
 

JackD201

WBF Founding Member
Apr 20, 2010
12,308
1,425
1,820
Manila, Philippines
Congratulations Phil! That looks like a beauty!

Hi Sam! Miss you neighbor !
 

jadis

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines
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. :D
 

JackD201

WBF Founding Member
Apr 20, 2010
12,308
1,425
1,820
Manila, Philippines
The elbow bump is the new normal :D
 

jadis

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines

mullard88

Well-Known Member
Jun 5, 2010
948
62
1,588
Miss you too Jack. You're another one I look forward to getting together with after this quarantine is over.
 

JackD201

WBF Founding Member
Apr 20, 2010
12,308
1,425
1,820
Manila, Philippines
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 :D

Need to get you a power cord Phil ;)
 
  • Like
Reactions: gian60 and jadis
Apr 5, 2020
6
1
8
73
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.
 

musicfirst1

VIP/Donor
Mar 8, 2015
504
309
395
Canada
www.musicfirstdistribution.ca
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.
 
Last edited:
  • Like
Reactions: jadis

AudioLibertarian

Well-Known Member
Dec 25, 2017
204
75
135
NEW YORK CITY
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

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines
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

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines
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.
 
  • Like
Reactions: AudioLibertarian

jadis

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines
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.

viber image 2019-04-07 , 20.09.28.jpg
 

jadis

Well-Known Member
Apr 28, 2010
12,361
5,471
2,810
Manila, Philippines
No pots or trimmers either from the top chassis.

20220127_173434.jpg
 
  • Like
Reactions: Jond

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing