HY60
 

"Eeysore Lying Criminal ****wit "

Even pro amps with SMPSs don't make any serious attempt
to regulate the rails.

** Shame how so many of them do - you know nothing ASS !!

Like all the ones with PFC corrected PSUs !!!!!!!!!!!!!!

That's merely the effect of the more stable DC bus. It's NOT
'regulation'.

** It most certainly IS regulation of the DC supply rails

No, PFC correction simply provides a fairly stable live side DC bus.


** It is actually very stable - you KNOW NOTHING LYING ASS.

The output will still sag a bit under load but somewhat less than it would
otherwise.


** MONSTROUS FALSEHOOD.

The DC rails are well regulated against AC supply voltage variations as well
as load variations.

There is no double mains frequency ripple voltage.

Max power output is NOT a function of AC supply voltage any more.

The PSU is ****ING REGULATED !!




....... Phil

HY60
 

TonyL wrote:

Phil Allison wrote:

It depends very much on the type of regulator topology.

A zener controlled emitter follower is not very low Z

Phil,

I don't understand that....explain ??

He's talking out of his bottom as usual, expecially of you use a Sziklai
pair. And you will at least need a darlington pair so why not use a
better configuration ?
http://en.wikipedia.org/wiki/Sziklai_pair

Q2 is the power device and Q1 the driver but in this case for
*stability* some small capacitance at the output may be advisable.
Rememver that 2N3055s etc don't have much in the way of current gain, so
Q1 can't be some tiddly TO-92 type device.

Graham

HY60
 

Woody wrote:

[sni[]
Interestingly, one of the amp modules still has some 10nF ceramics
soldered to the power rails.

Does that suggest that there may have been a slight problem with
instability in the unit design if it needs to be decoupled right at the
input.

No. That's a GOOD place to have some low ESR capacitance, not back at the
bloody PSU FFS. 10n sounds a little on the low side to me though. I use
100n film caps.

Graham

HY60
 

David Looser wrote:

"Phil Allison" wrote
"Eeyore" wrote:

The *thickness* of the case is almost irrelevant.

** No it is NOT you LYING ****wit.

**** OFF !!

Heatsinks work by transferring the heat from the device to the air. What
matters is the contact area between the heatsink and the air, and how easily
the heated air can move away to be replaced by colder air. So shape matters
too, as does how the heatsink is oriented and what obstructions there are to
the free movement of air around it (something that seems to be lost on far
too many designers, who seem to think that putting a fan somewhere nearby
will cure anything). The thermal conductivity matters too, of course, but if
it's aluminium then that isn't likely to be a problem unless the heatsink
was so thin as to be mechanically unsound. So thickness of the metal is, as
Graham said, almost irrelevant.

Except when you've got a LOT of watts to get rid of like up to 1 kW in one of my
designs. Even so, it wasn't *that* thick then either. Individual fins were 1.5mm
ali. Plus a little trick to improve heat transfer by avoiding laminar air flow.

Graham

HY60
 

Arny Krueger wrote:

"Eeyore" wrote
Eiron wrote:
Eeyore wrote:

Don't be silly. Even Metallica isn't square waves with
no dynamic range.

or twice that using 4 ohm speakers.

Who mentioned 4 ohm speakers. Other than you ?

Serge and Woody mentioned them.

But not the OP. Whom I hope is aware of the issue.

Haven't you heard, or heard about, the new Metallica CD?
It was in the news recently that it was so compressed
that even heavy metal fans were complaining, so pretty
close to square waves with no dynamic range.

I heard about the poor dynamic range.

It won't be square waves though, so no worse than
full-power sinewave. And no matter how hard you compress
it'll probably still have 3 dB of dynamic range. I speak
as someone who has run such tests.

The fact that there are concurrent significant signals at different
frequencies literally decimates the peak-to-average ratio.

I've managed to compress to 2 dB dynamic range in an EXTREME test.

Graham

HY60
 

Arny Krueger wrote:

"Rob" wrote

I still don't understand this 'all modern amplifiers
sound the same' thing - hence the question!

The chore that a power amplifier addresses is pretty simple and the means
for engineering equipment to perform that chore is pretty well understood
and documented.

It's astonishing how many really quite bad ones still get made though.

Graham

HY60
 

"Eeysore the CRIMINAL LIAR "

TonyL wrote:

Phil Allison wrote:

It depends very much on the type of regulator topology.

A zener controlled emitter follower is not very low Z

Phil,

I don't understand that....explain ??

He's talking out of his bottom as usual, expecially of you use a Sziklai
pair.


** Which is a change of context.

YOU ****ING LIAR !!!



...... Phil

HY60
 

Phil Allison wrote:
"TonyL"
Phil Allison wrote:

It depends very much on the type of regulator topology.

A zener controlled emitter follower is not very low Z


Phil,

I don't understand that....explain ??


** What bit needs explaining?


Well, almost by definition, a constant voltage generator is low Z with a
simple emitter follower typically having an output impedance of 1 Ohm.
Unless you are referring to the reduction of Hfe at higher frequencies or
currents.

Am I missing something ?

TonyL

HY60
 

Eeyore wrote:
This isn't a
commercial design that has to be right first time.

Yeah .... but if you break even one of the modules it won't be a
design at all.


True, but we are talking thermal lag here. Nothing is going to heat up so
quickly that I will not notice it and I do test circuits as I construct
them. Naturally, I will soak test those supply rails when I have determined
what order of current the HY60s will be drawing at various signal levels.
Just as I already tested the unregulated part of the power supply tonite.
This is all basic stuff, and probably quicker then arguing about it in here
:-)


You have calibrated fingers ? I use thermocouples.


Probably necessary in your profession. For me I use the rule of thumb
(!).... if it
is becoming uncomfortable to touch then it is too hot. Works for me.

TonyL

HY60
 

"TonyL"
Phil Allison wrote:

It depends very much on the type of regulator topology.

A zener controlled emitter follower is not very low Z


Phil,

I don't understand that....explain ??


** What bit needs explaining?


Well, almost by definition, a constant voltage generator is low Z with a
simple emitter follower typically having an output impedance of 1 Ohm.


** A simple emitter follower using a 2N3055 ( plus driver transistor) will
not exhibit " 1 Ohms output Z. It may be in the order of 0.5 ohms, which
is too high for your purpose.

Without a large output electro, the 2N3055 (or MJ2955) has to pass current
peaks of up to 5 or 6 amps instead of under 2 amps DC with it.

Plus - a simple emitter follower cannot SINK current at all.

Under inductive load conditions, when the protection circuits inside the
HY60 operate, it becomes essential for the PSU to be able to absorb some
pretty large current pulses - which a large value electro can do easily.

Enough ?


...... Phil