Pass Headphone Amp

dejanm · 12th March 2012, 05:17 PM

When Nelson Pass is going to make a headphone amp, either under the Pass Labs brand name or as the First Watt unit ?

I believe that there is a market for a such product and we haven't seen here many DIY works either. I can recall only one guy did an adaptation of Aleph circuit to make a headphone amp ...

Rodeodave · 12th March 2012, 05:55 PM

There are some Pass inspired circuits around, haven't built any of them myself though, so I can't comment any further.

Favorite Threads and Posts in "Pass Labs"

labjr · 12th March 2012, 06:45 PM

Need a Baby F5.

dejanm · 13th March 2012, 02:00 PM

We need some ultimate Pass design for the headphone amp ... I went quickly through posted links but except one Aleph adaptation, everything else is not really Nelson Pass ...

6L6 · 13th March 2012, 02:30 PM

There is an Aleph Mini build here -- 6moons audio reviews: Reality Check with Terry Aben

The reviewer is completely in love with it!

But no details on how to build it...

qusp · 13th March 2012, 03:06 PM

I would have thought that a pass headphone amp would need carefully chosen headphones to work to satisfaction due to lower damping factor than most pure headphone amps. ive toyed with the idea myself on many occasions and figured the F4 for a good candidate

jacco vermeulen · 13th March 2012, 03:35 PM

Quote:

Originally Posted by qusp

carefully chosen headphones to work to satisfaction due to lower damping factor than most

hi-hi

(DF is loudspeaker impedance divided by source impedance)

Zen Mod · 13th March 2012, 04:07 PM

damn Dutchie

where you see loudspeakers in headphones ?

(especially when they're around short circuit)

qusp · 04:49 PM

hmm not quite sure i'm with you jacco; i'm aware its an interaction between the 2, thus the need for carefully chosen headphone impedance to meet the higher than normal output impedance of an aleph headphone amp. myself i'm not even that convinced its a factor with most headphones, given a low enough outputZ and taking into account sufficiently electro-mechanically damped headphone construction, but last time i said that i got shot down. most references i have seen refer to grados

ahh i see where i created confusion, with the word 'factor' my apologies.

6L6 · 13th March 2012, 04:50 PM

Damping Factor is the speaker's impedance divided by the amp output impedance. (Just like Jacco said)

Looking at the Firstwatt website, the Aleph J (The closest thing to a 'normal' Aleph) has an output impedance of 0.4ohm.

So that amp has a damping factor of 20 into an 8ohm load 8/.4=20

Into the low impedance Grado (32ohm) headphones it would have a Damping Factor of 80 32/.4=80

Into a 320 ohm headphone the DF would be a very good 800!

12th March 2012, 05:17 PM	#1
dejanm diyAudio Member Join Date: Jul 2005 Location: Vienna	Pass Headphone Amp When Nelson Pass is going to make a headphone amp, either under the Pass Labs brand name or as the First Watt unit ? I believe that there is a market for a such product and we haven't seen here many DIY works either. I can recall only one guy did an adaptation of Aleph circuit to make a headphone amp ...

12th March 2012, 05:55 PM	#2
Rodeodave diyAudio Member Join Date: Dec 2004 Location: in the alps Blog Entries: 1	There are some Pass inspired circuits around, haven't built any of them myself though, so I can't comment any further. Favorite Threads and Posts in "Pass Labs" __________________ Gravity - Making the G since 13.7 billion B.C.

13th March 2012, 02:30 PM	#5
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	There is an Aleph Mini build here -- 6moons audio reviews: Reality Check with Terry Aben The reviewer is completely in love with it! But no details on how to build it... __________________ llustrated Build Guides - Pass Pearl 1 - Pass B1 - - Pass F5 - Pearl 2 - -O2 HPA - - Pass F4

13th March 2012, 04:07 PM	#8
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	damn Dutchie where you see loudspeakers in headphones ? (especially when they're around short circuit) __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb

13th March 2012, 04:43 PM	#9
qusp is choosing a less facetious title... diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	hmm not quite sure i'm with you jacco; i'm aware its an interaction between the 2, thus the need for carefully chosen headphone impedance to meet the higher than normal output impedance of an aleph headphone amp. myself i'm not even that convinced its a factor with most headphones, given a low enough outputZ and taking into account sufficiently electro-mechanically damped headphone construction, but last time i said that i got shot down. most references i have seen refer to grados ahh i see where i created confusion, with the word 'factor' my apologies. Last edited by qusp; 13th March 2012 at 04:49 PM.


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12th March 2012, 06:45 PM	#3
labjr diyAudio Member Join Date: Apr 2003 Location: MA	Need a Baby F5.

13th March 2012, 02:00 PM	#4
dejanm diyAudio Member Join Date: Jul 2005 Location: Vienna	We need some ultimate Pass design for the headphone amp ... I went quickly through posted links but except one Aleph adaptation, everything else is not really Nelson Pass ...

13th March 2012, 03:06 PM	#6
qusp is choosing a less facetious title... diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	I would have thought that a pass headphone amp would need carefully chosen headphones to work to satisfaction due to lower damping factor than most pure headphone amps. ive toyed with the idea myself on many occasions and figured the F4 for a good candidate

13th March 2012, 04:50 PM	#10
6L6 diyAudio Member Join Date: Oct 2010 Location: Denver, Colorado	Damping Factor is the speaker's impedance divided by the amp output impedance. (Just like Jacco said) Looking at the Firstwatt website, the Aleph J (The closest thing to a 'normal' Aleph) has an output impedance of 0.4ohm. So that amp has a damping factor of 20 into an 8ohm load 8/.4=20 Into the low impedance Grado (32ohm) headphones it would have a Damping Factor of 80 32/.4=80 Into a 320 ohm headphone the DF would be a very good 800! __________________ llustrated Build Guides - Pass Pearl 1 - Pass B1 - - Pass F5 - Pearl 2 - -O2 HPA - - Pass F4

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