Current from PassLabs amps - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 2nd October 2008, 04:26 PM   #11
Gyuri is offline Gyuri  Hungary
diyAudio Member
Gyuri's Avatar
Join Date: Nov 2003
Location: Budapest
Originally posted by Nelson Pass
Perhaps you should keep your ML-3's and be happy.

I believe it in that manner this allowable style, which a gentleman may allow to himself,.
The criticism attacking him was legitimate even, even not.
And this is not because of the others in this manner, but the man's own inner urge his reason.
Let somebody recommend something instead of the "in this manner" because I catch brain hemorrhage otherwise then now.

Nelson, (Grey ) I know it, that you from me you catch brain hemorrhage but what you believe about the film?
If it is not going some other way, then in a personal letter, if you
or ( you ) have a tiny time for me!
But if it is not, tells me, I will not take offence.
I know that you have many other tasks well, than to deal with idiots,like me.
I say thank you for the ones until now to you very much already.

Anyway anybody else relevant opinion interests.
The members' big part gets out from the humanity's more reasonable part mostly here because I believe it
in that manner.
The lord of old skies, already again this "manner".
I apologise to everybody, who from a reason like that like this, now or once, even in the future I hurt it.

But let me notice it because of that, quite injurious it, if peoples appearing reasonable pass over the other
man's opinion in silence.
I apologise to everybody once more, but somewhere away was needed let me say my thoughts.
Even then, if possibly these not too really to the object appropriate.
Let the moderators' lightnings strike down on me even because of this.
With respect:

Those who would have deserved the life they are all dead already. "Oh, my dead dears!" - Captain Cat
  Reply With Quote
Old 2nd October 2008, 08:56 PM   #12
diyAudio Member
Join Date: Dec 2002
Location: Mexico
can anybody translate the previous post??
  Reply With Quote
Old 2nd October 2008, 09:15 PM   #13
diyAudio Member
Join Date: Feb 2001
Location: Columbia, SC
The frightening thing about Gyuri's posts is that--though I can't understand a word of what he's saying--there are members here for whom English is a native language whose posts are even more opaque. Keep at it, Gyuri. One of these days I'm going to get the hang of reading your posts.
On the matter of current into loads and Pass Labs product...
At one point--and I believe it's still true--Nelson would bias a given circuit as hard as a given chassis would allow. For example, he might have two chassis sizes. You'd see a stereo version of the little one, then a higher powered monoblock using the same chassis. The larger one would also be available in stereo and monoblock variations. For two sets of metal, he'd be able to market four amps. Being able to buy face plates, tops, bottoms, heat sinks, and so forth in fewer sizes but larger quantities saved money on the production end. I haven't sat down and back calculated the rails/bias/heat dissipation of the current Pass Labs lineup, but I wouldn't be surprised if it worked out that he was still doing the same thing.
To beef up the sound quality is simple...bias the thing harder. But that might entail a larger power transformer (or using the same size transformer to run a monoblock) and very likely more heat sinking, either or both of which could push the amp into a larger chassis, which would cost more and require a higher retail price. It's easy to say that price is no object, but it is for many people and will become more so as the economy continues to deteriorate.
The obvious question then becomes, "Well, can I turn up the bias on my Pass Labs amp, myself?" And my equally obvious answer is to ask Nelson's permission first, as it's likely to void the warranty. Should you choose to do so on your own, keep an eye on the rail voltages (as well as the heat sink temperatures). If they collapse, you've gone too far.

  Reply With Quote
Old 2nd October 2008, 09:37 PM   #14
diyAudio Member
Stuart Easson's Avatar
Join Date: Oct 2002
Location: Santa Cruz, CA
Send a message via MSN to Stuart Easson Send a message via Yahoo to Stuart Easson
Default OT: Translation...

Does anyone else think Gyuri's quite enigmatic posts are the result of an automatic, perhaps computer based translator?

The idioms and vocabulary do not seem typical of speakers for whom English is a second language.

I wonder if he is having as much trouble understanding us...

My 2c

  Reply With Quote
Old 2nd October 2008, 09:45 PM   #15
The one and only
Nelson Pass's Avatar
Join Date: Mar 2001
He is referring to the movie Zeitgeist, which is being released liegitimately
on the web tomorrow. If you have 2 hours, it looks very interesting.

Going back to the subject of current from Pass amplifiers, I suggest that
maximum current output is obtainable from the XA160.6 and XA100.5, as
these have twice the output stage per channel and twice the output current.
of the same-chassis-size stereo amplifiers. My data indicates nominal
limiting at 40 amps without regard to output voltage.

  Reply With Quote
Old 2nd October 2008, 10:13 PM   #16
diyAudio Member
Join Date: Jul 2007
whatever the reasons for your dismay of the Pass-amp are, the power capability for sure isn't.
Even in large rooms you will never drive the full 350W into 8R speakers, your neighbours would get deaf instantly.
My neighbours do not get deaf with 350 Watts @ an eight Ohm speaker cause mine is 82 dB/1w meter 4 Ohms nominal with dips approaching 1 Ohm electrostatic one. Psycho-acoustically doubling the soundpressure takes ten times the power so that gives a maximum of 110 dB (given the measured 600 Watts @ 4 Ohms for the X-350.5)
I never expressed any dismay with PassLabs products in this thread. I just wondered why this this amp that sounds so wonderfull (first posting from me "The sound was very good vocals moved to the front there was depth and musicality at last.") got his ampmeter very quick at the rightcorner of its scale given his 250 Watts rating. I think I know now why this so after reading the Stereoplay review, especially the labreport, of the more powerfull X-350.5.
Passlabs seems to be tailored for an optimum power-envelope between 8 and 4 Ohms and not below that point for probably good reasons I would like to know.
Reading the article 'Power Supplies: Commentary for Consumers' from Nelson Pass where he makes a stand for a big powersupply:
First, third and fourth alinea at the 'Conclusion' :
"So what have we learned here? In general it takes big money to buy the big hardware to make really good power amplifier supplies.

Engineering being the science of compromise, each manufacturer
draws their own cost/benefit line, and it has been my experience that most manufacturers are quite conscientious about this. The degree of sophistication and massiveness of a supply has the context of the price of the product, and your expectations should be scaled accordingly.

As a consumer, you want the best sound you can get. You can
accomplish that through critical listening. As a secondary goal, we all like to get what seems to be good hardware value, and we want to know that that the manufacturer has actually put some real money into the product which costs a small fortune. If you can read the specs or look under the hood, the power supply, being one of the most expensive parts of the amp, usually is a good indicator. It should be the biggest and heaviest part of the amplifier."

I looked under the hood of many similar priced designs Levinsons (like a no. 333) , Rowlands (like model 5 or 8) and Krells (like a KSA 300s and FBP 600) and I can read the specs and Nelson Pass is right when he states that "Engineering being the science of compromise, each manufacturer draws their own cost/benefit line, and it has been my experience that most manufacturers are quite conscientious about this."

I'm just curious where he has drawned the line when it comes to powersupplies in his designs compared to the above mentioned.

I think that's a valid and legitimit question and there's no need to get defensive or annoyed about this matter.
  Reply With Quote
Old 2nd October 2008, 10:38 PM   #17
The one and only
Nelson Pass's Avatar
Join Date: Mar 2001
Originally posted by BrianEno
Passlabs seems to be tailored for an optimum power-envelope between 8 and 4 Ohms and not below that point for probably good reasons I would like to know.
We deliberately design the amplifier to shunt the front end to the output
when the drive voltage to the follower output stage exceeds twice the
total bias + 0.7V. This keeps output devices from exceeding their DC
SOA figures, and this way we get very few of them back for repair.

Some manufacturers emphasize the arc-welder capacity of their amplifiers -
we specialize in sounding as good as possible into reasonably ordinary
speakers. This is of course an arbitrary decision on our part, but we are
content with it. There are more powerful amplifiers on the market, and we
are happy to see them get their share of business as well.

  Reply With Quote
Old 2nd October 2008, 11:25 PM   #18
diyAudio Member
Join Date: Jul 2007
Thanks Grey and Nelson Pass for the explanations.

Of course I'm not in the market for arc-welding amplifiers. Your referring probably to a insane demonstration, conducted by Mark Levinson himself or Thom Colangelo to show the stiffness, of a ML-2 or 3 it was I believe, of their powersupplies) I tr to find a good sounding and for me technically matching amp.

I heard lots of good things about the Passlab products and I have had good experience with Threshold Stasis designs from the eighties.
Maybe I should sell my Acoustats and find me a more sensitive and sensible (regarding the load) speaker although I bought one of the last pair of 2 + 2's in 1991 and kept them till now never felt the inclination to replace them as with other equipment.
  Reply With Quote
Old 2nd October 2008, 11:33 PM   #19
diyAudio Member
hifimaker's Avatar
Join Date: Oct 2003
Location: San Jose
Originally posted by Nelson Pass

Some manufacturers emphasize the arc-welder capacity of their amplifiers -

I just completed a course on tig welding. I'm still laughing my can off thinking about other people watching in amazement as I use a big audio amp as a welding current source!

  Reply With Quote
Old 3rd October 2008, 01:28 AM   #20
diyAudio Member
Join Date: Feb 2001
Location: Columbia, SC
Supposedly there was a demonstration using a Phase Linear to drive (as I heard it) a small air conditioner. Pop a 60Hz signal in the front and hook up the air conditioner to the back.
Stunts like that are nifty in their own way, but least for me, because I don't care to listen to air conditioners. Or welding rigs, for that matter.

  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Commercially available current dumping amps? Key Solid State 30 23rd May 2009 10:19 PM
Current Source Amps zenmasterbrian Subwoofers 36 29th September 2006 06:38 AM
Current Planet Audio Amps 69CamaroSS396 Car Audio 1 30th July 2006 03:29 PM
increasing current(amps) by splicing wires ivan_dimitrov Parts 21 27th February 2006 05:42 PM
High Current Amps markheth Solid State 19 2nd February 2005 08:55 PM

New To Site? Need Help?

All times are GMT. The time now is 11:49 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2