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Industry Circles => Odyssey Audio => Topic started by: sz28 on 30 Sep 2016, 12:45 am

Title: Amp biasing again...
Post by: sz28 on 30 Sep 2016, 12:45 am
Hello everyone, I want to check the bias and re bias, if necessary, my Odyssey Stratos monoblocks without having to ship them in. I am comfortable working with electronics and have the required tools. I haven't been able to find instructions online to do this myself so I was wondering if someone might be able to pm me the instructions or point me to an online source I would greatly appreciate it. :thumb:

Title: Re: Amp biasing again...
Post by: sz28 on 30 Sep 2016, 03:00 pm
Big thanks to germay, he sent me what I needed! :thumb:
Title: Re: Amp biasing again...
Post by: klaus@odyssey on 3 Oct 2016, 03:42 am
late to the party,  but good....and thanks germay....
Title: Re: Amp biasing again...
Post by: germay0653 on 3 Oct 2016, 07:44 pm
Glad to help out.  I got them originally from Nicholas Bedworth.  Gery
Title: Re: Amp biasing again...
Post by: AnalogDog on 2 Nov 2016, 01:40 pm
Thanks to Germay, I just got mine rebiased too. They'd drifted down to -13mv! Yoiks!....no wonder they were sounding off song!
Got all 4 sides (I've got Kismet monoblocs) zeroed out, and rock stable at -22mv. WHAT a difference! THESE are again the amps I fell in love with 7 years ago! I won't let 'em go that long again....anyone have suggestions as to how often they should be checked? Thanks again to germay, and to Klaus for making such a simple and easy design to work with!
Title: Re: Amp biasing again...
Post by: paul79 on 2 Nov 2016, 02:47 pm
Surprised that difference in bias made that much of a difference... Glad to hear they are singing nicely for you though!   :thumb:
Title: Re: Amp biasing again...
Post by: AnalogDog on 2 Nov 2016, 07:36 pm
I've got Audio Physic Virgos...they are very very revealing of anything amiss in the signal chain. But boy, do they sing when everything is dialed in!
Title: Re: Amp biasing again...
Post by: uncola on 9 Nov 2016, 03:38 am
Germay can I have the amp biasing instructions too?  I have the week off may as well do stuff I was putting off.  Also going to stick sorbothane under my laptop :p
Title: Re: Amp biasing again...
Post by: aaron.luebke on 10 Nov 2016, 12:17 am
Me too?  I have some crudely written directions and I'd like to see if I can clean them up.
Title: Re: Amp biasing again...
Post by: germay0653 on 11 Nov 2016, 11:34 pm
Instructions sent. :thumb:

Just make sure they're plugged into the outlets your going to use them from when in your system.  I believe, Klaus correct me if I'm wrong, this is why Klaus asks for the outlet voltage readings from you when you purchase them.  He probably sets the the A/C voltage, somehow, to what you each provide when he biases them.
Title: Re: Amp biasing again...
Post by: aaron.luebke on 11 Nov 2016, 11:45 pm
Got it!  Thank you.  :thumb:
Title: Re: Amp biasing again...
Post by: tubesrule on 12 Nov 2016, 08:34 pm
Germany can I also get instructions on bias my Khartargo mono blocks. My email is ryriken66@att.net
Title: Re: Amp biasing again...
Post by: germay0653 on 13 Nov 2016, 12:20 am
Sent!
Title: Re: Amp biasing again...
Post by: tripwr1964 on 13 Nov 2016, 05:33 pm
just dialed my khartago mono's in this morning to -21.5mv and offset near 0.  much better now!
thks all for the help.  this is a very simple process once you figure it out.
however, i don't advised to drink a pot of coffee (and eat nothing) whiling doing it!  lol

and thanks klaus for a design that can be easily adjusted!
Title: Re: Amp biasing again...
Post by: tripwr1964 on 13 Nov 2016, 07:57 pm
read thru all the bias threads on this forum....

these are mono amps.

do you bias using tp1 and tp2 to a neg mv
or
do you bias using tp3 and tp4 to a positive mv

i've read folks adjusting to -21mv and 21mv

maybe this is a stupid question but have to ask.
Title: Re: Amp biasing again...
Post by: germay0653 on 14 Nov 2016, 03:11 am
You should follow the instructions. -21mV for both sides as a starting point (middle),  -18mV for darker/analytical and -24mV for warmer sound.  The mono is bridging the two channels together into one.
Title: Re: Amp biasing again...
Post by: tripwr1964 on 14 Nov 2016, 12:11 pm
got it.
thanks Germay!
going to listen to them a few days at -21.5mV (i was at -15 to -17mV) to see if i like them there.


Title: Re: Amp biasing again...
Post by: Zolanji on 18 Nov 2016, 04:46 pm
As the new owner of a nice pair of Stratos Mono Extremes, I would like to check the bias, and how to set the offset ( right now at .13mV and .07mV).  I have no idea how old they are, nor what the bias would have been originally set for.  It would be nice for piece of mind to check them myself.  I am planing on returning them to Odyssey for a "tune up" and possible upgrades sometime in the future, but would like to know where I am starting from. IF someone could send me the instructions, that would be greatly appreciated!

Title: Re: Amp biasing again...
Post by: questz1z on 29 Nov 2016, 10:41 pm
Germay I have a 6 month old pair of Kismets and I wanted to check/adjust the bias for my peace of mind. I absolutely love the amps and I want to keep them in proper adjustment. Can you please send me the adjustment instructions. My email address is questz1@comcast.net. THANKS in advance!
Title: Re: Amp biasing again...
Post by: robbiesurp on 30 Nov 2016, 03:45 pm
Germany can I also get instructions on bias my Khartargo mono blocks.

Thanks!
Title: Re: Amp biasing again...
Post by: Hadro on 8 Dec 2016, 10:20 pm
Could someone kindly tell me how I can get a copy of these biasing instructions?

Thanks
Title: Re: Amp biasing again...
Post by: germay0653 on 9 Dec 2016, 12:03 am
Hadro, check your messages!
Title: Re: Amp biasing again...
Post by: Alvin on 10 Dec 2016, 06:48 am
Germay can I have the instruction on how to bias my odyssey stratos monoblock.
Title: Re: Amp biasing again...
Post by: Hadro on 11 Dec 2016, 03:34 am
Thank you!
Title: Re: Amp biasing again...
Post by: questz1z on 15 Dec 2016, 10:48 pm
THANKS Germay, got the instructions, used them and everything is even better. One channel was pretty close but the other was off by about 4 mv. Everything is now balanced and nirvana.  THANKS Again!     -Tim
Title: Re: Amp biasing again...
Post by: germay0653 on 16 Dec 2016, 03:38 am
  :thumb:
Title: Re: Amp biasing again...
Post by: 88man on 17 Dec 2016, 02:57 am
Dual Mono is a real pain to bias since R + L ch. PCBs are stacked on top of one another, necessitating unscrewing the top R ch, lifting it up gently, and biasing the bottom board with magnification and bright lighting. Sonically, the amp sounds less bright, a welcome change. Heating issues are resolved too. However, the soundstage is a bit smaller now, and some of the 3-D magic is gone. Perhaps it's due to the flatter response?

Before Biasing:  R ch: 32mV, 34mV. L ch: 29mV, 28mV
After Biasing: R ch: 21mV, 21mV. L ch: 21mV, 21mV

Germay, you're the man! :thumb:
Title: Re: Amp biasing again...
Post by: germay0653 on 19 Dec 2016, 12:12 am
@88man,  you might want to play with repositioning and toe-in of the speakers to maybe bring back some of that 3D magic.
Title: Re: Amp biasing again...
Post by: cementhead on 19 Dec 2016, 02:13 pm
Hey, Germay. one more please. Jeff@gsflatwork.com. thank you :thumb:
Title: Re: Amp biasing again...
Post by: germay0653 on 19 Dec 2016, 08:57 pm
On the way Jeff!
Title: Re: Amp biasing again...
Post by: 88man on 23 Dec 2016, 04:21 am
@88man,  you might want to play with repositioning and toe-in of the speakers to maybe bring back some of that 3D magic.
Thanks Germay. Phew, the 3-D magic is back! It took a few days but there's definitely less glare on CDs. I also replaced the AudioQuest CopperHead interconnects with Shunyata Venoms. Even less glare, completely neutral accross the spectrum, and improved coherence.
Title: Re: Amp biasing again...
Post by: germay0653 on 26 Dec 2016, 05:19 pm
High purity, OCC copper is sweet that way.
Title: Re: Amp biasing again...
Post by: agburns on 29 Dec 2016, 01:45 am
germay0653,  I would appreciate if you could seen me the instructions. thanks
Title: Re: Amp biasing again...
Post by: Indiansprings on 2 Jan 2017, 06:21 pm
I have a pair of Stratos mono's too. Would you send me instructions as well?
Title: Re: Amp biasing again...
Post by: germay0653 on 3 Jan 2017, 07:25 pm
Just so all of you know, you don't need to supply your email address publicly.  I can PM you the instructions via Audiocircle!!
Title: Re: Amp biasing again...
Post by: cheehpogi on 11 Jan 2017, 11:51 am
New Comer here, can you p.m. me the instructions too Germay, many thanks.
Title: Re: Amp biasing again...
Post by: jn316 on 24 Jan 2017, 11:43 pm
Sorry to join the fray, but I have a Dual Mono that is about 8 years old that I would like to check. Instructions please.
Thanks in advance!
Gary
Title: Re: Amp biasing again...
Post by: Snegov on 27 Jan 2017, 10:46 pm
Germay can I have the instruction on how to bias my odyssey stratos monoblocks please.
My email is snegov@seznam.cz.
thanks in advance
Title: Re: Amp biasing again...
Post by: germay0653 on 30 Jan 2017, 06:42 pm
@Snegov,  PM with instructions sent!
Title: Re: Amp biasing again...
Post by: hifimonk on 4 Feb 2017, 09:59 pm
Germay, when you get a chance could you PM me instructions for biasing Khartago stereo. Thanks
Title: Re: Amp biasing again...
Post by: germay0653 on 7 Feb 2017, 08:49 pm
PM sent!
Title: Re: Amp biasing again...
Post by: hifimonk on 8 Feb 2017, 03:35 am
PM sent!

Thanks Germay !
Title: Re: Amp biasing again...
Post by: Cor0086 on 28 Feb 2017, 03:00 am
Can I get a copy also?
I just purchased a second hand khartago se

Thanks
Title: Re: Amp biasing again...
Post by: germay0653 on 2 Mar 2017, 03:20 am
PM Sent!
Title: Re: Amp biasing again...
Post by: Cor0086 on 2 Mar 2017, 03:22 am
PM Sent!

 :thumb: :thumb: :thumb:
Title: Re: Amp biasing again...
Post by: mtho33 on 6 Mar 2017, 07:12 am
germay0653 - can you PM me biasing instruction? I have just purchased second hand Odyssey Mono Extreme (upgraded to Kismet).
Thank you.
Title: Re: Amp biasing again...
Post by: erniek on 18 Mar 2017, 05:03 pm
I just had a dedicated line installed for my Khartago and am wondering if it needs to be re-biased?
Title: Re: Amp biasing again...
Post by: TJHUB on 18 Mar 2017, 05:37 pm
I just had a dedicated line installed for my Khartago and am wondering if it needs to be re-biased?

Since you're incoming voltage hasn't changed, no re-biasing should be necessary. 
Title: Re: Amp biasing again...
Post by: johnzm on 21 Mar 2017, 01:26 pm
could someone pm me the instructions? the last set of instructions i got was somewhat confusing and after probing and seeing wild numbers i did not trust myself to turn the right knobs to fix it.


Thanks!
Title: Re: Amp biasing again...
Post by: EquinoxDesignLab on 21 Mar 2017, 04:52 pm
Hey Germay, could you send me the instructions as well? Curious to see where my Stratos lies. Thank you very much!
Title: Re: Amp biasing again...
Post by: ldandha on 21 Mar 2017, 10:23 pm
Hi Germay, would you please send me the biasing instructions as well.  Thanks in advance!
Title: Re: Amp biasing again...
Post by: germay0653 on 21 Mar 2017, 11:25 pm
PM's, with instructions, sent to johnzm, EquinoxDesignLab and Idandha!
Title: Re: Amp biasing again...
Post by: Audionautic on 31 Mar 2017, 11:31 am
Hi Germay-
Please send me the details for Stratos Monos biasing when you can? Many thanks!      -Tom
Title: Re: Amp biasing again...
Post by: germay0653 on 1 Apr 2017, 02:50 pm
PM sent!
Title: Re: Amp biasing again...
Post by: David C on 1 Apr 2017, 03:01 pm
At the risk of sounding like I know what I'm talking about, would it not be easier to have a biasing link on the Odyssey website to give instructions? BTW I  unfortunately don't own an Odyssey but have heard the amps at an audio show and they are really great amps, very well built and sound way above their price point by far.
Title: Re: Amp biasing again...
Post by: germay0653 on 3 Apr 2017, 01:20 am
That would be up to Klaus!
Title: Re: Amp biasing again...
Post by: rikhav on 3 Apr 2017, 02:56 am
Hi germay
Can you PM me as well the instructions to rebias the amp

I have a stratos extreme stereo. My power supply is 230 volt so do I have to follow a different set of readings?

Title: Re: Amp biasing again...
Post by: germay0653 on 5 Apr 2017, 02:27 pm
PM sent.  I don't believe the board voltages change based on the main input voltage but you should check with Klaus to validate that.
Title: Re: Amp biasing again...
Post by: rikhav on 5 Apr 2017, 08:19 pm
Thank you so much
I also have same opinion as you about voltage , still will try to call Klaus and confirm the same
Title: Re: Amp biasing again...
Post by: johnzm on 14 Apr 2017, 12:19 pm
so if they are monoblocks, there are two knobs inside the case that adjust the bias. the instructions do not mention this. is there any additional info on setting bias for monoblocks?
Title: Re: Amp biasing again...
Post by: cementhead on 14 Apr 2017, 09:41 pm
call Klaus on the monos. you cannot cross the leads inside between the boards. VERY important! He sent the instructions, It took a little figuring out, But I got it.
Title: Re: Amp biasing again...
Post by: germay0653 on 15 Apr 2017, 03:10 pm
The instructions I've given to all were for the monos.  The stereo and mono implementations essentially use the same board.  Mono's are just bridged but you still have to adjust both sides of the board regardless.

I got them from Nicholas Bedworth, who got them from Klaus and Nicholas reviewed the Kismet in Stratos cases on 6moons when they came out.
Title: Re: Amp biasing again...
Post by: keven1031 on 16 Apr 2017, 11:08 am
Hey Germay,

I'm a new owner of a pair of used Kismet in Stratos Monoblocks. I've had them about a week and they're settling in nicely. Not sure of the breakin period for them but am expecting improvements over the next few months. I'd appreciate more info on the biasing procedure....being able to check the current bias and (down the road) have the ability to tweak will be great.

Thanks,
Keven
Title: Re: Amp biasing again...
Post by: johnzm on 5 May 2017, 12:54 am
can someone post up the information or pm me on biasing the monoblocks? i followed the stereo instructions and im pretty sure i didnt do it right as i only turned one of the adjusters.
Title: Re: Amp biasing again...
Post by: Lincnabby on 8 May 2017, 11:18 pm
Hi Germay0653,
I know you've PM'd several folks already, but would you please send the biasing instuctions to one more person? I just bought a used stereo version of the Kismet in a Khartago case. At this point it does not sound so great, so I'm hoping biasing will help. I've only had it for a couple of days, but have had it plugged in 24/7. Hoping it needs to settle down and recharge caps wise, but I'm guessing the bias is off too, as it sounds very weird- super bassy one day, very clinical and analytical the next, with very shallow soundstage.

Thanks so much for help!
Lincoln
Title: Re: Amp biasing again...
Post by: eartho on 3 Jun 2017, 06:26 pm
Hi all, i've very recently picked up an older used Stratos Stereo and would love to be able to check and adjust the bias. If anyone has the instructions they could pass my way, i'd greatly appreciate. Thank you.
Title: Re: Amp biasing again...
Post by: deadhead on 10 Jun 2017, 11:38 am
I'm new here and just purchased a Khartago stereo amp.  Klaus sent me instructions but I believe they're for someone who has an understanding of where and what to adjust.  Does someone have a step by step, possibly with pictures, of how to do this?  I have a multimeter, what other tools will I need? 

Thanks in advance,

Jeff
Title: Re: Amp biasing again...
Post by: klaus@odyssey on 15 Jun 2017, 12:10 am
Will guide Jeff over the phone.......
Title: Re: Amp biasing again...
Post by: khoadk2193 on 22 Jun 2017, 02:17 am
Hi Germany,

Can i have the bias instruction for khartago stereo? My email is khuongdaikhoa@hotmail.com. I really appreciate it. Thank you :D
Title: Re: Amp biasing again...
Post by: deadhead on 29 Jun 2017, 02:39 pm
Spent 20 minutes Tuesday night with Klaus biasing my Khartago.  Right away the bass, treble, and mids fell into their proper place.  After 36 hours the bass has extended and tightened up nicely.  Very happy with the sound.

Thanks to Klaus for excellent customer service and his patience with my questions.
Title: Re: Amp biasing again...
Post by: Stablemate on 3 Jul 2017, 06:43 pm
Requesting instructions too, please. Thanks!
Title: Re: Amp biasing again...
Post by: germay0653 on 6 Jul 2017, 02:12 am
PM sent Stablemate!
Title: Re: Amp biasing again...
Post by: A_shah on 7 Aug 2017, 01:37 am
Can some one please explain to me why we need to bias the amplifier ? all I hear is how do it what milivolts it should be ?
for instance I have a kismet/Stratos amp. which has been biased at at 122 Volts it's fully broken in by now and sounds very good , but using "kill a watt meter "I see that the fluctuation on my outlet  seems to range in the morning from 115 volts to 121.7 averaging at about 118.7 volts most of the time  should I now re bias the amplifier? or  just leave it  the way it is because I am very happy with the way it sounds right now .
Title: Re: Amp biasing again...
Post by: Vunce on 2 Sep 2017, 02:15 am
Germay,
I also request Stratos bias procedure:-)
Thank you,
Vinny
Title: Re: Amp biasing again...
Post by: Golden Ears on 10 Dec 2017, 06:15 pm
I have Odyssey Kismets in Stratos cases , double symphonic line caps, big transformers  Klaus walked me through the bias procedure once before but I hate to bother him again

Anyone have photos of the bias procedure. It makes a huge difference in the sound of the amps.
Title: Re: Amp biasing again...
Post by: loki1957 on 10 Dec 2017, 07:29 pm
Could I get directions as well. I've had my Kismets for years and have never biased them. I can't believe they can sound much better.
Thanks, John
Title: Re: Amp biasing again...
Post by: Hear Clifford Brown on 20 Dec 2017, 11:04 pm
Hi Germany,

Can I have the bias instruction for Stratos stereo extreme?  It's about 7 years old, I'm the second owner since last week and it sounds good to me but I'd like to check the bias.

Your assistance is much appreciated!

Thank you,
Jeff

 :thumb:
Title: Re: Amp biasing again...
Post by: deadhead on 20 Dec 2017, 11:33 pm
Someone needs to post a YouTube video
Title: Re: Amp biasing again...
Post by: Longandstraight on 22 Dec 2017, 12:02 am
I sure would like the instructions also. Just bought a pair of 3 yr old Kismets in Stratos cases. Sounds even better after the upgrade to WBT  705 Nexgen speaker posts and 0210  Nexgen rca inputs.  Just like them to be the best they can be !! 
Thanks Russ
Title: Re: Amp biasing again...
Post by: daven3871 on 4 Feb 2018, 04:25 pm
Hi Germany

Would gladly appreciate instructions for a Khartago extreme stereo. Bigshotclark@gmail.com  TIA
Title: Re: Amp biasing again...
Post by: germay0653 on 5 Feb 2018, 06:54 pm
PM, with instructions, sent, daven3871.
Title: Re: Amp biasing again...
Post by: Magnatest on 15 Feb 2018, 11:08 am
Hi Germay-

  Will you please send me the instructions for biasing Khartago monoblocks? Thank You.      -Gregg
Title: Re: Amp biasing again...
Post by: goingsolo on 15 Feb 2018, 11:18 am
Hi Germay,

I would like to receive a copy for biasing a pair of Khartagos please.

Thanks.
Title: Re: Amp biasing again...
Post by: tubesrule on 21 Feb 2018, 02:27 am
Could you email me too for Khartargo mono block bias
Thanks
Title: Re: Amp biasing again...
Post by: germay0653 on 21 Feb 2018, 10:45 pm
Here you go.  Of the two sets of instructions, the one that refers to From Klaus himself have given me the best results!

Instructions for biasing

The amplifier should be at operating temperature. If you've been playing music, wait perhaps 10-15 minutes for everything to "settle down".

The board is basically two channels, bridged into a monophonic amp, and essentially there are two "sides" to the board corresponding to the left and right channels in the stereo versions.

First check the output offset, which is the voltage between pads 6 (+) and 5 (-). The (+) wire going to the speaker cable terminal on the back of the amp is on pad 6. Set the DVM to 200 mV DC, put the positive lead of a DVM onto 6, negative lead onto 5, and adjust the trim pot way at the opposite end of the board (not the one in the middle) to zero out the offset. Don’t worry about small offsets, say 1 mV or less.

Repeat for the other channel, with the negative lead on pad 5, positive on 7.

Now, go back to the other side, negative lead on pad 5 or other convenient signal ground, and check TP 5 and 6 to see which one has the highest value (they will be slightly different). This time, use the trim pot in close to TP 6 to set the bias, using the TP point that had the higher voltage, to be about -21 mV. Repeat on the other side, checking TP 1 and 2, and use the trim pot near TP 2. Be careful not to short anything to the power transistor case which I think is grounded.

Then check the offset values again as they may have changed slightly, recheck the bias, etc.

The bias controls the "voicing" of the amp. -18 will be colder, -24 mV will be warmer. Klaus recommends -21 mV as a starting point.

Per Klaus himself:

Make sure that you have the red probe on the speaker out, and only use that part of the board for biasing,  as the board is true mirror image...then move the probe into the other post and bias that part of the board...for offset,  probe - goes to opening 7 or 8 (ground of the unused speaker outs on the board)...offset pots are the 2 close to the face plate,  get the offset close to 0 mV....then for the actual bias go only into TP's 3, 4, 7, and 8...ignore the others, and use the one on each side with the higher value....pots are next to the transistors.......20 mV's....again,  PLEASE  make sure that you move the red probe from side to side,  as the 2 sides of the board right through the middle act independently !!!!!!!!!!!!!!

walk away from it, come back after 10 minutes, check, and repeat if necessary until it is stabile........
Title: Re: Amp biasing again...
Post by: khoadk2193 on 22 Feb 2018, 03:36 am
I keep the (-) probe of my multi meter in the ground post and use the positive probe to check for TP 3,4,7 and 8. I got all of them around 21 mV DC. Am I doing this right?
Title: Re: Amp biasing again...
Post by: germay0653 on 22 Feb 2018, 04:18 pm
-, negative, -21mV
Title: Re: Amp biasing again...
Post by: johnzm on 28 May 2018, 05:14 pm
Here you go.  Of the two sets of instructions, the one that refers to From Klaus himself have given me the best results!

Instructions for biasing

The amplifier should be at operating temperature. If you've been playing music, wait perhaps 10-15 minutes for everything to "settle down".

The board is basically two channels, bridged into a monophonic amp, and essentially there are two "sides" to the board corresponding to the left and right channels in the stereo versions.

First check the output offset, which is the voltage between pads 6 (+) and 5 (-). The (+) wire going to the speaker cable terminal on the back of the amp is on pad 6. Set the DVM to 200 mV DC, put the positive lead of a DVM onto 6, negative lead onto 5, and adjust the trim pot way at the opposite end of the board (not the one in the middle) to zero out the offset. Don’t worry about small offsets, say 1 mV or less.

Repeat for the other channel, with the negative lead on pad 5, positive on 7.

Now, go back to the other side, negative lead on pad 5 or other convenient signal ground, and check TP 5 and 6 to see which one has the highest value (they will be slightly different). This time, use the trim pot in close to TP 6 to set the bias, using the TP point that had the higher voltage, to be about -21 mV. Repeat on the other side, checking TP 1 and 2, and use the trim pot near TP 2. Be careful not to short anything to the power transistor case which I think is grounded.

Then check the offset values again as they may have changed slightly, recheck the bias, etc.

The bias controls the "voicing" of the amp. -18 will be colder, -24 mV will be warmer. Klaus recommends -21 mV as a starting point.

Per Klaus himself:

Make sure that you have the red probe on the speaker out, and only use that part of the board for biasing,  as the board is true mirror image...then move the probe into the other post and bias that part of the board...for offset,  probe - goes to opening 7 or 8 (ground of the unused speaker outs on the board)...offset pots are the 2 close to the face plate,  get the offset close to 0 mV....then for the actual bias go only into TP's 3, 4, 7, and 8...ignore the others, and use the one on each side with the higher value....pots are next to the transistors.......20 mV's....again,  PLEASE  make sure that you move the red probe from side to side,  as the 2 sides of the board right through the middle act independently !!!!!!!!!!!!!!

walk away from it, come back after 10 minutes, check, and repeat if necessary until it is stabile........

that last little bit was what i was missing.

since it looks like many have asked, and i finally have complete instructions, i built an image to help everyone out.
by the way, to adjust the offset it is much easier if you have a ground lead that you can clip into the board. you might want to pick one up before you start.

(https://www.audiocircle.com/image.php?id=180585&size=huge)

Title: Re: Amp biasing again...
Post by: FullRangeMan on 28 May 2018, 05:28 pm
Thanks John for taking time to post this image.
Title: Re: Amp biasing again...
Post by: 88man on 4 Jul 2018, 02:23 pm
How often should the Stratos amp be rebiased? I rebiased mine 2 years ago. The amp is getting real hot again, and the sound is becoming sibilant and bright. Dual Mono is a real pain as the 2 boards are stacked on top of each other and you have to lift up the board while you balance the probes on the bottom board.
Title: Re: Amp biasing again...
Post by: Dishman442 on 7 Jul 2018, 09:22 am
Could please send bias instructions for Khartago mono amps?  It doesn’t appear Klaus will be able to get to an upgrade any time soon so I want to tune them up. (Just bought them used)  They already have been upgraded once and have the newer board should that matter with biasing.

My email is jstclair442@msn.com

If someone could do a YouTube we would all be eternally grateful!!
Title: Re: Amp biasing again...
Post by: Arcticdeth on 5 Apr 2020, 08:56 pm
Kismet pair.

Any more photos w step by step instructions. ..

Probst.
Title: Re: Amp biasing again...
Post by: ServerAdmin on 6 Apr 2020, 02:56 pm
Arcticdeth, change your profile now please.
Title: Re: Amp biasing again...
Post by: germay0653 on 7 Apr 2020, 05:37 pm
Kismet pair.

Any more photos w step by step instructions. ..

Probst.

Instructions are the same for mono and stereo.  Mono bridges the L & R channels so you need to adjust both, regardless of configuration.
Title: Re: Amp biasing again...
Post by: anirudh19oct on 8 Sep 2020, 02:36 pm
Need some help. Tried measuring the bias in between negative lead on 5 with positive lead on TP1, TP2 and TP5, TP6 on my newly acquired (used) Kratos. The value on the DVM set to 200mV reads somewhere in between -2 and -5 on both sides. Shouldn't it be around -18 to -23 as suggested? DC offset says around -3 to -5 when checked with the instructions above mentioned for both channels.

Looking for some advice on this.
Title: Re: Amp biasing again...
Post by: SoCalWJS on 9 Sep 2020, 10:43 pm
Kismet pair.

Any more photos w step by step instructions. ..

Probst.
I should probably look into adjusting mine as well (Kismet in Khartago cases). Bought used and never checked.

But I’m a chicken  :green:. I’m afeared of zapping myself. Has anybody ever made a good tutorial (pictures, video) on this INCLUDING all of the things one need to do to avoid ZAPPING oneself? The above photos are helpful, but don’t have enough info for me to think about giving it a shot.

I’ve been “bitten” by electricity a few times and I want to avoid that having that experience again.
Title: Re: Amp biasing again...
Post by: WarmColors on 10 Sep 2020, 04:11 am
I should probably look into adjusting mine as well (Kismet in Khartago cases). Bought used and never checked.

But I’m a chicken  :green:. I’m afeared of zapping myself. Has anybody ever made a good tutorial (pictures, video) on this INCLUDING all of the things one need to do to avoid ZAPPING oneself? The above photos are helpful, but don’t have enough info for me to think about giving it a shot.

I’ve been “bitten” by electricity a few times and I want to avoid that having that experience again.

I've been "bitten" by electricity once and it wasn't fun at all!!!!
Lately I have been getting shocked due to static electricity it's really annoying me. I need to buy those bracelets that remove the static.
Title: Re: Amp biasing again...
Post by: arfan on 18 Oct 2020, 04:36 pm
Hopefully I'm not beating a dead dead horse on this topic, however, I haven't read a response on biasing a stereo Odyssey amp and measuring neg. values on TP1&2 and positive values on TP3&4. The same on the other side for TP5/6 and TP7/8. It appears that Klaus uses TP3/4, and TP7/8 points and indicates a positive 20 mv. I'm understanding that most use  TP1/2 -TP5/6 and adjusting to the neg. voltage. Has anyone had experience using the positive readings on the TP3/4 and TP7/8 points. I understand that the procedure is for monos, but should apply for stereo amp.

tripwire1964 in a old previous response has asked the same question on a mono amp, I'm biasing a stereo amp to a new house and voltage.
Title: Re: Amp biasing again...
Post by: klaus@odyssey on 18 Oct 2020, 05:30 pm
Plus,  minus...doesn't make a difference,  changes when you change probes....it is essentially the same with stereo amps on the bias,  just the offset is different in that you use the 2 binding posts on each side....







AGAIN,  AND AGAIN,  AND AGAIN  !!!!!!!!!!!!!!!!

Guys,  I don't have a problem with you optimizing the amps,  that's why I have the info out there....however,  please don't go completely neurotic like some have,  and ALWAYS  make sure that you use the left and right part of the boards and the CORRESPONDING  binding posts,  or otherwise pop goes the weasel. 
Title: Re: Amp biasing again...
Post by: arfan on 2 Nov 2020, 12:48 pm
Thanks Klaus for the clarification. The bias procedure is straight forward and appreciate all the posts on the topic. I moved to a new house with 124.2 volts and offset and bias was off considerably.
I would like to throw out a question on biasing with Magnepan 1.7's and some experience from members on the bias settings that they have settled on? I have Stratos extreme monos and Kismet kartago reference monos that I've e been comparing using with Magnepan 1.7's for a few weeks and the bias setting which seem to work for me is -22.5mv.
Thanks again for the help. 
Title: Re: Amp biasing again...
Post by: klaus@odyssey on 3 Nov 2020, 06:44 am
1.  124 V...this is exactly why I am so hot on the issue of biasing.....124 to, let's say a standard 120 V setting is HUGE !!!!   Huge in any amplifier design btw. 

2. Synergy with the Maggies is one of the 2 best I've ever found...just awesome...

3.  22 +  mV  would be a bit too much for my own personal taste,  but because there are dozens and dozens of different tweaks and upgrades out there in my nearly 7000 amps,  they also behave different in different systems,  et al.....

4.  Honestly,  don't listen to others about what's best on the test points...use your own ears,  and float your own boat......


VOTE !!!  AND STAY SAFE !!!!
Title: Re: Amp biasing again...
Post by: arfan on 3 Nov 2020, 10:07 pm
Thanks again Klaus. Good to know and appreciate your opinion on the  maggies and Odyssey amps, it helps to hear an expert on the subject and reinforces what I'm hearing.
When you Say too much on the bias setting, are you referring to a warmer setting? I have an Audible Illusions M3B Tube pre newest update and the match gives goose bumps to these old ears.

Title: Re: Amp biasing again...
Post by: klaus@odyssey on 4 Nov 2020, 08:00 am
In general and for most amps:

-  higher bias = rounder, fuller, more bass

- lower bias the opposite = faster, leaner, more detail oriented as a result


that's why I optimize the bias according to the tonal balance of the speakers,  within reason......but yes, if you want to get the absolute maximum of what's possible in the amp,  then we'll have to bias it just right....if that falls off,  then so does the sound.  That's also why it's a good idea to have me to adjust for a new owner if bought used,  and that's why I'm banging my head against the wall  when there's an idiot complaining about a used amp's performance when the bias is obviously off.

Again,  I can just go ahead and bias the amp 2-4 mV less than optimum,  but that's not really in my blood.....if you can go to 11,  then go to fukking 11 !!!!

Title: Re: Amp biasing again...
Post by: brad1138 on 2 Jul 2021, 03:06 am
I do want to check/adjust the bias in my Stereo Kismet in Khartago case. This appears to be the place to request the instructions. My Moabs love a warm amp, and as cool (temp wise) as my Kismet runs, I think it might be worth the check.

Klaus you already have my email, PM me if needed. (no rush)

Thank you!

PS, always go to 11! ;)   https://www.youtube.com/watch?v=KOO5S4vxi0o
Title: Re: Amp biasing again...
Post by: brad1138 on 2 Jul 2021, 05:39 pm
that last little bit was what i was missing.

since it looks like many have asked, and i finally have complete instructions, i built an image to help everyone out.
by the way, to adjust the offset it is much easier if you have a ground lead that you can clip into the board. you might want to pick one up before you start.

(https://www.audiocircle.com/image.php?id=180585&size=huge)


Again, thank you for that.

On the stereo version amps, wouldn't it be fine to just read bias from the speaker terminals? You wouldn't need a clip.

(https://i.imgur.com/VMYdNOph.jpg)
Title: Re: Amp biasing again...
Post by: brad1138 on 3 Jul 2021, 12:12 am
My bad, I read that wrong, You can read offset from spk terminals, not the bias. (Not the positive anyway)
Title: Re: Amp biasing again...
Post by: brad1138 on 5 Jul 2021, 06:18 pm
OK, I am fairly sure I have my head around it. It would have been easier if not for typos and contradictions in the posted instructions. Also the difference between mono and stereo complicate it a bit.

Johns nice picture is great, but it says TP6/7 when I am pretty sure he meant TP5/6.

The 1st part for the written instructions say to use TP1/2 & TP5/6, with no mention of TP3/4 or TP7/8. Then towards the bottom, it says use TP3/4 and TP7/8 and ignore TP1/2 & TP5/6....

I really don't know for sure which is correct, and why not use all 4 per side?

I think Johns picture instructions are the most easy to follow, short the typo.

If anyone could offer clarification on which TPs to use, that would be great.

It seems clear that you can connect the negative DVM lead to the negative speaker terminal, and leave it there for all testing (per side). The positive would go to the corresponding positive speaker terminal for offset and the "TPs" for Bias adjustment.

Thanks for the help, I am REALLY not trying to be obnoxious.  :)

Title: Re: Amp biasing again...
Post by: klaus@odyssey on 5 Jul 2021, 07:17 pm
OK,  Brad et al,

You only use 1 test point per side....!!!!!!!!!!!!!
Either TP  3 or 4 on one side,  and either 7 or 8 on the other....you only use the one with the highest value per side of the board and completely ignore the other 3 of that side !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

On another note,   Brad,  your Candela is ready to go !!!!
Title: Re: Amp biasing again...
Post by: brad1138 on 6 Jul 2021, 10:08 pm
OK,  Brad et al,

You only use 1 test point per side....!!!!!!!!!!!!!
Either TP  3 or 4 on one side,  and either 7 or 8 on the other....you only use the one with the highest value per side of the board and completely ignore the other 3 of that side !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

On another note,   Brad,  your Candela is ready to go !!!!

OK, thank you again. I understood you only use one, but you check 2 at first to verify which one is higher.

I spoke with Klaus on the phone just a few hours ago, he clarified to use the red speaker terminal, which is ground, for bias adjusting.  I always have it in my head that black is ground, so that confused me a bit.
Title: Re: Amp biasing again...
Post by: brad1138 on 6 Jul 2021, 11:51 pm
I just spoke to Klaus again for reverification. Red is not ground (I called him after I verified that with an ohm meter), but it is what is supposed to be used along with TPx for bias adjusting.

Every set of instructions posted in this thread says to use ground and TPx for bias THAT IS INCORRECT. He asked me to post that here, and he may chime in about it also.
Title: Re: Amp biasing again...
Post by: brad1138 on 10 Jul 2021, 06:02 pm
OK, I bought a 2nd Multimeter to compare and make sure they were both accurate.

Klaus recommends bias between 18 and 24 mV, my Kismet was 12 mV on both sides  :o . The offset was about 3 mV on left chan and 13 mV on right. Both within an acceptable margin. I am going to aim for 21 mV and 0 mV and see how it it sounds, then go from there.

(https://i.imgur.com/Sb6AgSrh.jpg)
Title: Re: Amp biasing again...
Post by: klaus@odyssey on 12 Jul 2021, 08:54 pm
Anybody trying to do this on your own,  CALL ME  FIRST !!!!!!!
Title: Re: Amp biasing again...
Post by: Hooge on 24 Mar 2023, 09:17 pm
Old thread here but it's a gem. I successfully just biased my 12 year old Khartago. One side was at about 18 mV and the other was about 21 mV. I assume this amp was biased at 21 mV at one time. I am trying the 24 mV and love the sound, just a touch warmer. Sounds fantastic. Love this amp! Thanks!