Pure Class A Push Pull

megasat16

heiney9 wrote: »

Absolutely bullet proof. I believe I saw Nelson talking about how hard they work to ensure a less than .01% failure rate of their amplifiers. There aren't a lot of designs out there that you can run into a direct short with out damage.
H9

Brock,

Don't tell me I am reading between lines again but I am curious what you mean by that.

Is Pass Labs or any other amps able to withstand the dead short without proper protection?

Or you are saying they can drive speakers with Ultra Low Impedance load at 1 ohms or less?

I know some amps are happy being an Arc Welder and destroy the speakers but are Pass Amps one of them?

heiney9

James I said there aren't MANY amps you can run into a direct short without either damaging the amp or it going into hard protect mode. I'm not saying the amp will output sound, just that you can short the outputs either for fun or on accident and no damage will occur, nor will the fuse blow, etc. Just unshort them and press play.

Try taking a normal amp like an Adcom at full output and then short the output terminals, tell me what happens. Be sure to have a fire extinguisher handy as well as a second amp if you want to listen to your tunes.

WTH, does everything with you have to be such a twist on words or why do you have to read a negative or absolute statement into everything I say. You are constantly in "attack" mode and it really does get tiresome.

H9

heiney9

megasat16 wrote: »

Brock,

Is Pass Labs amps able to withstand the dead short without proper protection?

Yes, there is no need for output protection (nor is there any protection) on the Aleph series. Read the literature, ask NP.

It was a statement about the build.

H9

P.s. Never said it was EXCLUSIVE to Pass........just that it's not a common thing to be able to do with most amplifiers and a testament to the build and simplistic design of the amp. Oh, and also because someone asked the question......not just praise for praise sake!

heiney9

The amplifier also does not have the auxiliary pull circuitry which allowed the Aleph to deliver very high currents into low impedance loads. This is a purer approach, however it does not allow for greater power below 4 ohms. The amplifier will drive and is stable into any load impedance or reactance including a direct short, and delivers clean audio into very tough loads.

heiney9

The amplifier is powered by a toroidal transformer which charges 120,000 uF capacitance. This unregulated supply feeds the output transistors only with a full power ripple of about .3 volt. The power draw of this system is constant regardless of the music playing through the amplifier. As such, it does not depend on a high quality AC outlet or special power cords, since the dynamic performance does not create a variation in AC line draw. If the AC line is running low, the output stage will bias to a higher current level by way of compensation.

The amplifier is stable into any load impedance or reactance including a direct short. The Aleph 30 is impervious to electrostatic shock at the input and dead shorts at the output.You can safely plug and unplug inputs and outputs while the amplifier is running. (Do not trythis with other products).The Aleph 30 is protected from overheating by a 75 degree C. thermostatic switch, and from internal failure by a slow-blow fuse.

heiney9

heiney9 wrote: »

WTH, does everything with you have to be such a twist on words or why do you have to read a negative or absolute statement into everything I say. You are constantly in "attack" mode and it really does get tiresome.

H9

James, disregard my rant here, I re-read your post and realized I never made it clear originally and you were just asking a question, not trying to be clever and twist things around like you sometimes tend to do. I wish I could edit because it was my mistake for going off on a little rant :redface: when it was not necessary.

H9

heiney9

The input devices are slightly better than the originals, but significant improvement is to be found in the manner of matching the input devices. Previously the input differential transistors were merely matched to each other, but beginning with the Aleph 30 they are now matched both to each other and to the rest of the amplifier circuit. We select the input devices as part of the complete amplifier, swapping them in and out until the best performance is achieved.

Tweaking the input stage in this manner and with other adjustment techniques we have been able to significantly lower the noise floor and improve the power supply noise rejection of the amplifier. Typically the Aleph 30 has about 6 dB greater dynamic range compared to the Aleph 3.

We have increased the number of output power Mosfet devices from four per channel to six. These are the same devices as the original Aleph 3, and are matched in the same manner, taken from the same lot codes and matched to about 2% Vgs. The greater number of devices lowers the distortion and improves the damping factor by about 50%, and also allows us to run the bias up a bit, giving higher heat sink temperatures but with the same on-chip temperatures.

Just a bit more insight as to the reliability and hands on approach which makes them so well built.

Does that help Tom? Perhaps as Doro stated you really don't care about the minutea. I do.

H9

FTGV

heiney9 wrote: »

WTH, does everything with you have to be such a twist on words or why do you have to read a negative or absolute statement into everything I say. You are constantly in "attack" mode and it really does get tiresome.

H9

James stop being a bully

treitz3

Oh, no. I definitely wasn't trolling. It was a legit and honest inquiry question about the reliability. I would also like to say that while I didn't care before? This recent experience has raised my curiosity quite a bit and now I'm all ears....and I'm not just talking about "just" the speakers and the end result as to what hits your ears anymore.

Thank you.

I haven't looked this up at all yet [time constraints] but I'm curious. How much does a pair of these bad boys typically go for on the used market? Well, that and how often would you say they show up for sale?

treitz3

I'm hesitant to even look at your suggestion due to the fact that every Krell I have heard throughout my audio journey [regardless of source and speaker type] was just too clinical. Sterile would be another good way to describe them to these ears. It's not that they are bad amplifiers, it's that they are just not in my tastes of what I personally would consider a great sound signature.

A good way for me to put it in layman's terms for you [from my perspective] would be that whenever I auditioned them, they sounded good but I never felt the urge to start tapping my toes to the music. To me they are sterile and clinical, not musical.

The ones you linked may sound different but throughout the auditioning of the Krells over the years, all of them had the same signature. Have you heard these by chance?

treitz3

treitz3 wrote: »

I haven't looked this up at all yet [time constraints] but I'm curious. How much does a pair of these bad boys typically go for on the used market? Well, that and how often would you say they show up for sale?

Oh, allow me to clarify. I'm talking about the 200w model Alpha. Not a DIY kit, the actual amps. I'm not having any luck finding any information online.

[Deleted User]

As an aside I remember an Audio magazine review of an early Mark Levinson amp where they actually did a little welding on a small piece of steel. Of course this has no bearing on the quality of the sound, but most reliable reviewers felt the amp sounded very good with the correct matching gear. So lots of current and good fidelity.

FTGV

I have always thought his analagy of sound in air being single ended and equating it to amplification was a bit of a stretch.
As for his push/pull symmetrical comments he has apparently had a change of heart in the years since developing his Aleph line.Now all of his X and XA series amplifiers are fully balanced push/pull designs a topology he calls Super Symmetry.

megasat16

FTGV wrote: »

James stop being a bully

Ok Fred. I agreed. :redface:

Hey Brock, Stop being such a Cry Baby! :biggrin:

Now, tell me what the use of an amp that doesn't play into 1 ohm load all day long and said to be stable into all impedance or reactance load? :eek:

When you quoted the Pass Amp Manual, You missed this part. It's one of the most single important disclaimer of every manufacturer.

"The warranty does not include damage due to misuse or abuse or modified products and also does not include consequential damage."

Unless it's explicitly defined by the manufacturer in the Specification, driving low impedance speakers with constant 1-2 ohms load is the same as ABUSING.

If you want any amp to live long and trouble free, don't Abuse it regardless of how well it's made.

If I say any further, you'll think I am trashing Pass Amps.

I got a lot a lot more to say but me no bully.

megasat16

fastz28 wrote: »

The amplifier is stable into any load impedance or reactance including a direct short, and will
deliver clean audio signal into 4 ohms at 600 watt peaks. Into lower impedances it will deliver
approximately 12 amp peaks.

it is stated stable at any load and direct short

I am not being mean but does it mean it can drive 1 ohm load resistor into maximum output?

Very Few Amps (possibly very large Threshold and some Large Pass among them) may be able to drive 1 ohms music load.

But there are specially made amps to drive constant 1 ohm or less load all day long.

How about 1 ohm load for an hour?

I am quite familiar with Amplifiers ratings and the manuals.

heiney9

megasat16 wrote: »

I am not being mean but does it mean it can drive 1 ohm load resistor into maximum output?

Very Few Amps (possibly very large Threshold and some Large Pass among them) may be able to drive 1 ohms music load.

But there are specially made amps to drive constant 1 ohm or less load all day long.

How about 1 ohm load for an hour?

I am quite familiar with Amplifiers ratings and the manuals.

James, say whatever you want. Again, you're reading everything but the kitchen sink into what I quoted from the excellent and thorough manual. If a manufacturer of NP's knowledge and reputation says you run the amp into a direct short without damage I believe him. No idiot in their right mind would do this on purpose. It speaks to the simplicity and robustness of the design, nothing more, nothing less.

All that other other gobbly-**** you wrote up there has nothing to do with it. The amp is stable into any load, interpret that anyway you want. Of course amps specifically designed to run 1 ohm loads will do it better, probably much better. Again, I thought this was a given. Most of us here in this discussion aren't noobs.

Anyway this has become very tiresome and non-productive, have fun.

H9

heiney9

megasat16 wrote: »

I am not being mean but does it mean it can drive 1 ohm load resistor into maximum output?

Very Few Amps (possibly very large Threshold and some Large Pass among them) may be able to drive 1 ohms music load.

But there are specially made amps to drive constant 1 ohm or less load all day long.

How about 1 ohm load for an hour?

I am quite familiar with Amplifiers ratings and the manuals.

NP is over at the Pass Forum at DIYAUDIO, you should ask him, then you'll know. I simply quoted the manual, you are now extrapolating that info trying to find an answer. 1) you can experiment yourself 2) ask the designer 3) stop reading "into" every single post.

I don't know where fastz28 copied the quote about 600watts peak. He started quoting from the Aleph owners manual and the Aleph isn't close to 600watts peak........so I dunno where that came from.



H9

megasat16

heiney9 wrote: »

James, say whatever you want. Again, you're reading everything but the kitchen sink into what I quoted from the excellent and thorough manual. If a manufacturer of NP's knowledge and reputation says you run the amp into a direct short without damage I believe him. No idiot in their right mind would do this on purpose. It speaks to the simplicity and robustness of the design, nothing more, nothing less.

All that other other gobbly-**** you wrote up there has nothing to do with it. The amp is stable into any load, interpret that anyway you want. Of course amps specifically designed to run 1 ohm loads will do it better, probably much better. Again, I thought this was a given. Most of us here in this discussion aren't noobs.

Anyway this has become very tiresome and non-productive, have fun.

H9

Hey Brock,

1. If you are going to quote the manual, I expect some kind of answer what it means. I want to know what you think or understand as a NP fan or owner from the quoted text from the Manual. I am not the one with the clever words and the one who wrote the manual uses some clever words too.

2. Stop being a cry baby and stop saying unnecessary BS. Answer if you know; don't answer if you don't know. Simple and Easy as is.

3. Pass Amps are well built Amps. It's no doubt about it. But again, don't Abuse it regardless of how well it's made. Don't Encourage Anyone with the idea everything that NP amps are less failure coz it's said in the manual.

4. Stop saying I twist the words around and using clever words. I spell out in Black and White in No. 3.

5. My reply is to FastZ coz he quoted the text from Aleph 1.2 twice. I mean no disrespecting to him but I've read it the 1st time he posted it. If he post something from the manual, I simply ask the same question to him too.

Now, I know where to find Mr. Pass and I would more than happy to ask in DIYA. :rolleyes:

megasat16

heiney9 wrote: »

I don't know where fastz28 copied the quote about 600watts peak. He started quoting from the Aleph owners manual and the Aleph isn't close to 600watts peak........so I dunno where that came from.



H9

He is using Aleph 1.2 manual from the long post he made.

You are using Aleph 30 Manual.

I know where to find the info on Pass. Thanks :biggrin:

heiney9

megasat16 wrote: »

I know where to find the info on Pass. Thanks :biggrin:

Apparently not since you have so many questions.....:biggrin:.

I highly encourage you to go over to the Pass forums, he will answer and discuss just about anything. He's quite active over there.

I can't answer your questions, nor do I really care since I don't intentionally abuse my gear nor do I have difficult speaker loads. Also, I am in no way encouraging abuse of anyones gear.

For the last time, it speaks to the simplicity of the design and the robustness of the parts used and overall design, that was my singular point when Tom asked if they were reliable. Nothing more, nothing less.

H9

mhardy6647

Kenneth Swauger wrote: »

As an aside I remember an Audio magazine review of an early Mark Levinson amp where they actually did a little welding on a small piece of steel. Of course this has no bearing on the quality of the sound, but most reliable reviewers felt the amp sounded very good with the correct matching gear. So lots of current and good fidelity.

It is also widely stated that salespeople used to plug early series Bose 901s into the wall to demonstrate their power-handling capability :-)

megasat16

As far as I know, the old Levinson ML2 is the only amp that sounds good with the Original Apogee Speakers.

I heard the later Levinson ML20.x are also very good sounding with the matching gears.

The Reference No. # 33 monobloc weights 400lbs each and makes any amp looks like an ant and most speakers tiny. But they are only 300W@8 ohms. They are really nice coz they have the full regulated power supply and follow the stiff voltage source power principle. They are capable to drive 2400W into 1 ohm load stable and spelled out under the Specifications in Black and White Text.

I think the only one that is heavier and mightier is Krell MRA (Master Reference Amplifier) and each monobloc weights 800-900lbs? I think Dan built only 7-8 pairs of them and cost a small fortune.

But these amps are more of a killer than a necessary.

So, I will go back to crank more Pass.

heiney9

James, I'll take these over the above

http://www.stereophile.com/solidpoweramps/699pass

If you're truly power-mad, a number of X1000s can be arrayed to produce up to 2000W per chassis. Two of them can deliver 4000W into 8 or 2 ohms, four can deliver 8000W into 4 ohms, and 16 will do 32,000W into 1 ohm! The mind boggles. "As a practical matter, we would expect peak output levels on the order of 64,000W for such arrays." Yes, as a practical matter. Ahem. Your dealer or Pass can supply you with the interface adapter(s) needed to run the amps in series or parallel.

megasat16

heiney9 wrote: »

James, I'll take these over the above

http://www.stereophile.com/solidpoweramps/699pass

If you're truly power-mad, a number of X1000s can be arrayed to produce up to 2000W per chassis. Two of them can deliver 4000W into 8 or 2 ohms, four can deliver 8000W into 4 ohms, and 16 will do 32,000W into 1 ohm! The mind boggles. "As a practical matter, we would expect peak output levels on the order of 64,000W for such arrays." Yes, as a practical matter. Ahem. Your dealer or Pass can supply you with the interface adapter(s) needed to run the amps in series or parallel.

Brock,

I hand it to you. lol

Pass Got the Bigga Fish to Fry. :biggrin:

Joe08867

heiney9 wrote: »

James, I'll take these over the above

http://www.stereophile.com/solidpoweramps/699pass

If you're truly power-mad, a number of X1000s can be arrayed to produce up to 2000W per chassis. Two of them can deliver 4000W into 8 or 2 ohms, four can deliver 8000W into 4 ohms, and 16 will do 32,000W into 1 ohm! The mind boggles. "As a practical matter, we would expect peak output levels on the order of 64,000W for such arrays." Yes, as a practical matter. Ahem. Your dealer or Pass can supply you with the interface adapter(s) needed to run the amps in series or parallel.

I love to see what these amps would have done with Ben's Frankenpolks. Holy crap 64,000w. Now that's a party!!!!!!!!1:eek::cool:

heiney9

megasat16 wrote: »

Brock,

I hand it to you. lol

Pass Got the Bigga Fish to Fry. :biggrin:

It's good for sh*ts and grins, but you know me, I'm not all about massive power.......unless one needs it of course .

Statement pieces for sure! All in good fun James. The Levinson's and Krell you mention are worthy as well. Again, being a Pass-o-phile I have several links as my favorites, that was one of them.

H9

megasat16

fastz28 wrote: »

my ps audio 200cx can drive Original Apogee Speakers all year with out a hicup and sound beautiful.

I think you are right on. PS audio makes very good amps too.

Joe08867 wrote: »

I love to see what these amps would have done with Ben's Frankenpolks. Holy crap 64,000w. Now that's a party!!!!!!!!1:eek::cool:

They'll smoke any known speaker except the Biggest Subwoofer and subwoofer arrays.

steveinaz

Sometimes I'm glad I have a sub-par amp.

FTGV

megasat16 wrote: »

As far as I know, the old Levinson ML2 is the only amp that sounds good with the Original Apogee Speakers.

The brutal load that some of those Apogee full range ribbons presented (and some ESL panels)may have been in part why Adcom decided to switch to a triple darlington configured output stage for the MKII version of the 555?

As for 1 ohm drive capability you can add the older Bryston 7B (ST,NRB)mono's which when used in their parallel mode could dump 800 ish watts into a 1 ohm load.

megasat16

FTGV wrote: »

The brutal load that some of those Apogee full range ribbons presented (and some ESL panels)may have been in part why Adcom decided to switch to a triple darlington configured output stage for the MKII version of the 555?

As for 1 ohm drive capability you can add the older Bryston 7B (ST,NRB)mono's which when used in their parallel mode could dump 800 ish watts into a 1 ohm load.

The ESL do love the high voltage gains. I think that's why some ESL comes with the step up transformer?

The Ribbons and Planars with low Z love current more than voltage. I think that's why the ML2 was an ideal choice for the Apogee at one time.

I guess the Voltage Rails on the 555 would be high to have triple Darlington gain stage? Not sure since I haven't checked one before.

I need to ask you the same question as I asked Brock. Coz he won't be too happy if I don't ask you and said I am taking it easy on you.

How do you know the Bryston 7B NRB and ST is capable of driving 1 ohm load in parallel mode? Does it applies to RMS capability or the drive for Occasionally dip at some Frequency? :biggrin:

I know where to find the Bryston Manuals and Schema but aren't you supposed to Quote like Pass boys do. :biggrin: