Question for Pass Labs Fans...

[megasat16]

I like the Accuphase but it's too much money. I don't have any Pass Labs Class A amps so I don't know what the ad said about Pass Labs Class A is true?

Quote from seller ad

"unlike most Pass Labs class A amps which tend to choke under 4ohm."


http://www.audiogon.com/cgi-bin/cls....se-A-60-stereo

[heiney9]

I like the Accuphase but it's too much money. I don't have any Pass Labs Class A amps so I don't know what the ad said about Pass Labs Class A is true?

Quote from seller ad

"unlike most Pass Labs class A amps which tend to choke under 4ohm."


http://www.audiogon.com/cgi-bin/cls....se-A-60-stereo

That is wholeheartly FALSE statement. The only amps that this *might* apply to is the First Watt amps. Those are special amps designed to run single driver speakers and horns. It also states that explicitly on the very informative owners manual.

You couldn't, for instance, drive LSi 7's with most First Watt amp designs. They are intended for a very small niche market type of speaker.

Any Pass Labs amp really can drive any load. NP states in the owners manual that, "I haven't encountered a load yet that the amp can't handle". Keep in mind the lower wattages of the pure class A amps will be the limiting factor not the ability to drive low impedances.

Ask Ricardo about his X250 and the Maggies that caused other lesser amps to clip.

Statements like the above are what really irk me.

/rant

H9

P.s. My lowly little 30wpc Aleph performs well beyond it's 30wpc rating and I have no doubt it would perform admirably into a low impedance load. In fact you can short the outputs with no damage to the amplifier.

[heiney9]

The thing missing in ANY single ended Class A amplifer is perhaps some damping. By nature of the single endedness they have lower damping capabilites compared to the same wattage or higher push/pull circuit.

If I had one very mild wish for the Aleph............is that on some material it had better damping. Not a big issue.....but one that can be noticed on some source material.

H9

[megasat16]

Thanks H9! I personally think that statement in general is very misleading. I don't think most (90%) Pass Labs amp will suffer under 4 ohms load.

Hope More Pass Labs Owner will chime in. :)

[heiney9]

Well besides the Aleph, there really isn;t anything in the Pass Labs line smaller (wattage wise). Today you have the XA30 and XA30.5 and those are even more robust than the Aleph. The Aleph J is a First Watt amp technically but it's essentially the Aleph 30 with Jfet's for the inputs. I'd put that at 100% assuming one doesn;t lump in the First Watt stuff. Those really are speciality amps, hand built in small runs for a VERY specific purpose.

H9

P.s. Now if your talking Ted's Sound Labs or Rich's Inner Sound panels, then the Aleph wouldn;t cut it. But those are specific types of speakers that present a very difficult load. You'd need a higher end Pass Labs amp to run those.

Typical driver speakers that present a 4 ohm load or less would be a piece of cake for any Pass Labs amps..................Period!!! :)

[Ricardo]

Not surprised to see that kind of BS statement from that seller.

The X250 can drive the MMG's with absolutely no problem, where the Marsh A400s started to clip at not so high volumes. The MMG's are supposed to have a flat 4 ohm impedance, but they do represent a very heavy load. Not sure why.

I'm with H9 on the damping factor. The Belles 350a Reference which is also a power house has a damping factor of over 2,000. That will control any woofer with authority. The X250 has a D.F. of "only" 250. Not sure if that would be an issue with traditional cone full range speakers, but I doubt it would be. In any case, not a problem with planar/ribbon speakers IME.

[Face]

Dampening factor is as relevant as watts.

[heiney9]

Actually Ricardo the "X" series has a much higher damping factor than the Aleph. Even the pure class A "XA" series has a higher damping factor. The patented cascoding arrangement helps increase it.....among other things.

[megasat16]

Thanks for chiming in guys! I have amps with Damping factor of 100 and have a good authority over woofers in many different speakers. I have amps with damping factors ranging from 500 to 1000 and it's not making any noticeable difference. I think damping factor of 20 is all that requires for a good authority over woofers.

[heiney9]

The Aleph is 200 according to the specs. I do notice some slight "sloppiness" compared to the Adcom I had on certain material. But the damping factor may not be the whole issue. I am ecstatic with the Aleph...........it will never leave................well perhaps for a higher up Pass Labs amp.

H9.

P.s. That Accuphase amp is incredibly nice.....just don't agree with that sentence by the hi-fi store.

[megasat16]

The Accuphase is incredibly nice but it's too much money. I wanted to get one for a long time but I am guessing if I should give up my Mark Levinson and a few other more amps just to get one amp with 60W WPC. But you know, watt is not the only thing that matters like your Aleph.

I hope the price for Accuphase comes down a bit or just have to wait for more affordable one.

[megasat16]

That will control any woofer with authority. The X250 has a D.F. of "only" 250. Not sure if that would be an issue with traditional cone full range speakers, but I doubt it would be. In any case, not a problem with planar/ribbon speakers IME.

I don't think any problem should exist with D.F of 250 for any kind of speakers designs regardless of conventional cone or planar type woofers is used. :)

[lakesailor]

I used to own a Pass Labs "X" series and had no issues driving 4 ohm loads whatsoever. It is a fairly robust amplifier. As Heiney mentioned maybe someone is confused with the First Watt series. Good Luck

[SCompRacer]

"unlike most Pass Labs class A amps which tend to choke under 4ohm."

Gotta love authoritive absolutes.

Damping factor is dependent on the impedance of the load. You would have to know the exact load impedance it was measured at. Usually measured with a stable resistive load. Trust your ears.

[GV#27]

Dampening factor is as relevant as watts.

When the speaker cables resistance and a real loudspeaker load is added to the equation the seemlingly high DF disappears.The big numbers don't tell the whole story.

[Hawkeye]

I have several friends using Pass labs (X350.5) driving Martin Logan speakers which can dip as low as .75 Ohm. Never heard the Pass choke on anything. Very nice sounding mps.

Gordon