Author Topic: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier  (Read 47798 times)

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Offline Fungus

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #125 on: January 14, 2016, 12:34:36 am »
More than a decade ago I bought a HP PDA which already did away with the 3.5 mm jack and used a 2.5 mm jack instead. Thoughtfully HP supplied a 2.5 mm to 3.5 mm adapter...

Apple will charge $20 for their legacy headphone compatibility system.

 

Offline krivx

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #126 on: January 14, 2016, 12:36:54 am »
More than a decade ago I bought a HP PDA which already did away with the 3.5 mm jack and used a 2.5 mm jack instead. Thoughtfully HP supplied a 2.5 mm to 3.5 mm adapter...

Apple will charge $20 for their legacy headphone compatibility system.

If it's an analog breakout cable then eBay will charge $3
 

Offline Richard Crowley

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #127 on: January 14, 2016, 01:03:39 am »
Just because they're removing the 3.5mm jack, doesn't mean it won't still output analog audio. They could very well push the analog audio over a couple of pins on the Lightning connector.
Please explain how you think they could do that since there are no analog pins on the Lightning connector, and no re-assignable pins, either. 

And furthermore, the Lightning connector is not only proprietary, but contains active circuitry to ensure that ONLY Apple-provided (or Apple-licensed) gear can connect.  (Read: $$$)

Ref: https://en.wikipedia.org/wiki/Lightning_(connector)
 

Offline Richard Crowley

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #128 on: January 14, 2016, 01:08:25 am »
Apple will charge $20 for their legacy headphone compatibility system.
If it's an analog breakout cable then eBay will charge $3
It cannot be an analog cable because Apples proprietary Lightning connector is digital-only.
Furthermore Lightning requires an active ID/authentication chip available only by licen$e from Apple.
That ensures that you won't be able to buy sensibly-priced accessories like simple cables, adapters, etc.
Apple must enforce their lucrative proprietary Walled Garden scheme.

Of course, the knock-off artists in Asia have proven themselves to be very clever.
So it seems within the realm of possibility that they can produce a counterfeit authentication chip.
Of course, then Apple could pull an FTDI stunt and brick all your counterfeit gear.
« Last Edit: January 14, 2016, 01:10:22 am by Richard Crowley »
 

Offline krivx

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #129 on: January 14, 2016, 01:31:09 am »
Apple will charge $20 for their legacy headphone compatibility system.
If it's an analog breakout cable then eBay will charge $3
It cannot be an analog cable because Apples proprietary Lightning connector is digital-only.
Furthermore Lightning requires an active ID/authentication chip available only by licen$e from Apple.
That ensures that you won't be able to buy sensibly-priced accessories like simple cables, adapters, etc.
Apple must enforce their lucrative proprietary Walled Garden scheme.

Of course, the knock-off artists in Asia have proven themselves to be very clever.
So it seems within the realm of possibility that they can produce a counterfeit authentication chip.
Of course, then Apple could pull an FTDI stunt and brick all your counterfeit gear.

The Wikipedia page posted above says that Apple sell a Lightning to 30pin (previous Ipod/IPhone connector) adapter and that it supports analog audio. Google brings up lots of knockoffs of this adapter, so maybe the work is already done?
 

Offline Brumby

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #130 on: January 14, 2016, 01:35:37 am »
I would not be comfortable trusting Apple to give me what I want - and I certainly am not one of the 'faithful' that accepts whatever is served up as being the best option.

I like to think and decide for myself on a few things....
 

Offline Fungus

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #131 on: January 14, 2016, 03:07:42 am »
Apple will charge $20 for their legacy headphone compatibility system.
If it's an analog breakout cable then eBay will charge $3
It cannot be an analog cable because Apples proprietary Lightning connector is digital-only.

Apple could just stick a new connector on the bottom with more pins.

It's not like they've never released an iPhone that was incompatible with previous-gen peripherals.
 

Offline jitter

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #132 on: January 14, 2016, 07:44:10 am »
How has this thread gone from a valve amplifier to an Apple thread?
 

Offline Richard Crowley

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #133 on: January 14, 2016, 07:52:46 am »
How has this thread gone from a valve amplifier to an Apple thread?
Discussion of the future of headphone interface (connector, impedance, etc.) is threatened by Apple's rumored decision to drop the industry-standard analog headphone interface (3.5mm or 6.35mm=1/4 inch) presumably in favor of digital and likely wireless interface. Rendering the valve headphone amps, already arcane, to the category of downright obsolete as well.
 

Offline bob808

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #134 on: January 24, 2016, 11:41:33 pm »
 

Offline Brumby

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #135 on: January 25, 2016, 01:53:36 am »
Much of the reaction is predictable - but one post made me smile.

This is probably the most honest attitude I have come across:
"My take is, even if there are no variables - all cables sound the same, all amps sound the same, all CD players and turntables sound the same (which of course I don't think is the case) the Fact that we Perceive improvements and gain increased enjoyment from them (even if in fact they aren't there) it's WORTH it. Perception is reality; not fact."

I have to agree that perception is the key factor in the appreciation of anything.  If someone feels happier about something that isn't real, then I can just shake my head and walk by quietly.

But have someone try to convince another that the extra $$$s are worth it - and I have a real problem.
 

Offline Brumby

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #136 on: January 25, 2016, 01:56:41 am »
Then there was this:
"His parents should have put the lid back on the red cordial."

Yeah - sometimes you can wonder about that... but, in the end, it's an honest opinion that's as entertaining as hell.
 

Offline rrinker

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #137 on: January 25, 2016, 04:27:50 am »
 I laughed out loud at this one:

what irritates also are clowns like the guy in the video, he didn't really offer any factual information nor present as someone really capable of doing so.  At one point he mentions 'sheilding' as though it's a snake oil selling term and holds up his basic black IEC power cable as though it's performance can't be bettered.

LOL doesn't offer facts?  :-DD :-DD :-DD :-DD
 

Offline Pentium100

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #138 on: January 25, 2016, 07:03:49 am »
Even if, for example, the signal from a reel to reel tape deck is inferior to the signal from a CD player (most likely with my tape decks and tapes, definitely for some recordings I have), it is still more enjoyable to me to listen to music while watching the big reels spin.

Tubes usually do alter the signal (SE amplifiers, for example, usually have a lot of 2nd order harmonics), so it's a matter of preference. I, for example, prefer the sound of my (lo-fi) tube tape recorder for some music even though other music on it sounds bad.
 

Offline c4757p

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No longer active here - try the IRC channel if you just can't be without me :)
 

Offline kalleboo

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #140 on: January 25, 2016, 08:30:41 am »
The Wikipedia page posted above says that Apple sell a Lightning to 30pin (previous Ipod/IPhone connector) adapter and that it supports analog audio.
And it actually contains a small DAC!

Google brings up lots of knockoffs of this adapter, so maybe the work is already done?
The cheap ones I've seen in stores all say "Does not support Audio/Video" on the box, e.g. this one on Amazon: http://www.amazon.com/DP-30-Pin-Adapter-Apple-Lightning/dp/B00D48Q4OG
 

Offline Fungus

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #141 on: January 25, 2016, 06:34:07 pm »
The Wikipedia page posted above says that Apple sell a Lightning to 30pin (previous Ipod/IPhone connector) adapter and that it supports analog audio.
And it actually contains a small DAC!

I don't trust it, it will have jitter.

Bring back the true analog output!
 

Offline krivx

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #142 on: January 25, 2016, 07:53:17 pm »
The Wikipedia page posted above says that Apple sell a Lightning to 30pin (previous Ipod/IPhone connector) adapter and that it supports analog audio.
And it actually contains a small DAC!

I don't trust it, it will have jitter.

Bring back the true analog output!

You don't trust the DAC in a cable, but a DAC inside the phone is OK?
 

Online blueskull

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #143 on: January 25, 2016, 09:23:17 pm »
You don't trust the DAC in a cable, but a DAC inside the phone is OK?

Clock directly driven by oscillator or SoC has much better jitter performance.
Clock recovered from USB is not, unless you go the async path and have a local oscillator, and discipline your data source to your local clock.
 

Offline rch

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #144 on: January 25, 2016, 09:48:28 pm »
You don't trust the DAC in a cable, but a DAC inside the phone is OK?

Clock directly driven by oscillator or SoC has much better jitter performance.
Clock recovered from USB is not, unless you go the async path and have a local oscillator, and discipline your data source to your local clock.

If it is mainly going to used to listen to music recovered from .mp3s I think that is a purely academic concern.  Even I can often hear gross compression artifacts, and I'm not musical.
 

Offline Fungus

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #145 on: January 26, 2016, 01:36:19 am »
I don't trust it, it will have jitter.

Bring back the true analog output!
You don't trust the DAC in a cable, but a DAC inside the phone is OK?

I thought the "true analog" would have given it away, but nooooo....  :-DD

 

Offline Brumby

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #146 on: January 26, 2016, 01:42:25 am »
The truth be known, Fungus wants his brick mobile phone back...
 

Offline gildasd

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #147 on: January 26, 2016, 02:23:45 am »
The truth be known, Fungus wants his brick mobile phone back...
Could a person even make* an all analogue GSM phone?


*That fits in the bed of a Medium Pickup and runs off no more than a Honda Handy generator of 700W.
I'm electronically illiterate
 

Offline mikerj

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #148 on: January 26, 2016, 04:16:24 am »
 

Offline bob808

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Re: EEVblog #837 - Reverse Engineering A Valve Headphone Amplifier
« Reply #149 on: January 26, 2016, 04:18:06 am »
I start to feel less and less sorry for them. I feel they should pay as much as possible for their arrogance :)
 


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