"paul packer" wrote in message
...
On Mon, 26 Mar 2007 14:28:56 +1000, "Trevor Wilson"
wrote:
**I was disparaging an RX-300U. I was not disparaging ALL Yamahas.
" Rotels are designed to operate with speakers.
Yamahas work better with dummy loads."
Enough said.
**Indeed. After you have tested as many Yamahas and Rotels (Marantz,
Pioneers, et al) as I have, then you will be well qualified to comment on
the relative qualities of each product.
Not the point. You said you didn't condemn Yamahas per se. Your own
words say you did.
**I stated fact. Nothing more. Into an easy load (headphones, relatively
resistive, 8 Ohm speakers) Yamahas are fine. Anything else, a Rotel will
clobber the Yammy, as Rotels (generally) possess far better load tolerance
than Yamahas (generally).
My comments about your use of headphones remain.
The use of headphones invalidates your claim to knowing how an
amplifier
sounds, for the vast majority of uses that the amplifier will be put
to.
If that's true then there is no way of knowing what an amplifier
sounds like, since it will sound different with every speaker
depending on load---there is no constant.
**BINGO! Give the man $64,000.00. Now you're learning. We also need to
understand that to suggest one amplifier for the vast majority of
situations, that amplifier needs to have a wide load tolerance and a
good
power supply. ALL Rotel amps satify those criteria, whilst only SOME
Yamahas
can manage SOME of the criteria.
And what if an amp has good load tolerance and will drive any speaker,
but nevertheless sounds lousy? Would you recommend that amp?
**Of course not. My point remains: Your experience with headphone
listneing
(only) makes your ideas of what constitutes a good amplifier as pretty
much
meaningless.
Not meaningless to me. Nor other HP users.
**Indeed. Does the OP intend to use his amp with headphones (exclusively),
or is he like the vast majority of listeners, who will be using speakers?
In a way headphones give a
true sound since they are not causing the amp any difficulty.
**Wrong. Headphones have many virtues, but all the listener can do is to
judge how the headphone circuit sounds (along with preamp sections, of
course) of any given amplifier. For instance: In general an amplifier
fitted
with a dedicated headphone amplifier (which Rotels are NOT fitted with)
will
tend to sound better than an amplifier which feeds the headphones
through
high value resistors from a speaker output stage (which is how Rotel and
most other amps do it). IOW: You may not be comparing apples with
apples.
Disagree.
**Then elaborate. Please feel free to be as technical as you wish.
Naughty, naughty, Trevor. I know you can do better.
**You don't wish to elaborate?
I've listened to a lot of amps through good phones, and the
best sounding are those that feed from the speaker output stage.
**How do you know? Have you examined the schematic to determine that fact?
Can you read a schematic?
Don't have to.
**Yeah, you do.
When I see leads from the speaker outlets to the
headphone outlet board which sports 2 (almost always) 330 ohm
resistors, I know how the phones are being driven. Not very technical,
but I'd like you to prove me wrong by pointing out the (very well
hidden) HP amp on the board that is actually driving the phones but
somehow, mysteriously, isn't connected to the phones board.
**A headphone amp may not be fitted to the headphone PCB. The series
resistors may not be fitted to the headphone PCB. In fact, I would be very
cautious about telling anyone which amp uses a particular technology unless
I had sighted the schematic.
And I've opened up a hell of a lot of amps.
**I'd venture to say that I have opened up somewhat more.
In
fact virtually all do anyway.
**Most do, some do not.
Playing with words. Virtually all do.
You may cite one or two exotic
exceptions,
**Nope. I can cite one or two which are hardly exotic, but use dedicated
headphone amplifiers.
Please do so.
**The vast majority of budget preamps, cassette decks and CD players, which
are fitted with headphone sockets.
* Nakamichi AV-10 (Crappy headphone amp, BTW)
* Pioneer VSX-D209 (Nice headphone amp, BTW)
* Yamaha RX-V800 (Not bad HP amp) BTW: Thos one has high value resistors on
the HP PCB.
* Denon AVR-1601 (470 Ohm resistors fitted to the HP PCB)
* Denon AVR-1801
* Denon AVR-3300
* Et al.
ALL the above amps employ dedicated headphone amplification. ALL employ
series resistance. SOME place that series resistance on the headphone PCB.
You MUST read the schematic to verify if this is the case.
but the fact remains that virtually all reasonably priced
amps feed the headphone socket from the speaker outlet through
resistors, and many sound brilliant while doing so.
**Nope. Acceptable - yes. Brilliant - no.
Matter of opinion. My opinion--brilliant.
**You're entitled to your opinion. However, I doubt that you've ever heard a
really good headphone amplifier either.
I have not been
impressed by dedicated HP amps, which sound thin and harsh by
comparison.
**Uh-huh. Which headphone amps?
MF X-Can v2
**Like all MF products - overpriced and over-hyped.
Little Dot 2 tube amp
**Don't know it, but I see no point in using valves to drive headphones. It
is a counter-intuitive idea.
A couple of Cmoys using different ICs
**Well?
Any number of Rotel and NAD pre-amps (which obviously do use separate
HP amps).
**And most are VERY ordinary. SOME are excellent.
My points remain:
* Judging an amplifier by it's ability to drive headphones is not
necessarily how most listeners hear their music.
* Unless you read (and can read) a schematic, you won't know if an amplifier
uses a dedicated headphone amplifier or not.
* Unless you know which type of output stage is used, you won't know if any
given headphone amp sounds good or not.
As you correctly surmised, most non-headphone amp equipped amplifiers use a
220 - 470 Ohm series resistor to limit power to the headphones. What you may
not know is that most headphone amp equipped amplifiers use similar value
resistors in series with very cheap OP amps to drive headphones. This is
just plain daft. Headphones, like speakers work best when sourced from a low
impedance source. I've mentioned this to you, many times and made
appropriate suggestions to improve your headphone listening. Nothing has
altered.
--
Trevor Wilson
www.rageaudio.com.au
--
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