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Re Valve amps



 
 
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  #1 (permalink)  
Old August 3rd 04, 08:31 PM posted to uk.rec.audio
StaffBull
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Posts: 12
Default Re Valve amps

Thanks for the helpful comments below - another question I have is if I
would leave a valve amp on all the time or switch it off and have to wait
for it to warm up every time I need it?
cheers


  #2 (permalink)  
Old August 3rd 04, 09:49 PM posted to uk.rec.audio
Dave Plowman (News)
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Posts: 5,872
Default Re Valve amps

In article ,
StaffBull wrote:
Thanks for the helpful comments below - another question I have is if I
would leave a valve amp on all the time or switch it off and have to wait
for it to warm up every time I need it?


Valves - unlike transistors - have a finite life. And according to some,
modern valves have a shorter life than once was the case.

I'd personally not trust many valve amps to be left on unattended - I've
seen too many go up in smoke. And certainly not a 'budget' valve amp.

--
*Hard work has a future payoff. Laziness pays off NOW.

Dave Plowman London SW
To e-mail, change noise into sound.
  #3 (permalink)  
Old August 3rd 04, 10:33 PM posted to uk.rec.audio
Andy Evans
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Posts: 759
Default Re Valve amps

I'd personally not trust many valve amps to be left on unattended - I've seen
too many go up in smoke. And certainly not a 'budget' valve amp.

Can't say it's ever happened to me, but the potential is there I suppose. Mind,
these days there should be fuses in strategic places. I tend to turn my amp on
in the morning and turn it off at night. With valve rectifiers there's a nice
slow warm up, so not much harm is done turning the amp off and on if you prefer
to do it more frequently. Valves for the most part are not too expensive -
cheaper probably than the batteries a household uses up in the same time span.
So far they have kept their value so spares can even be something of an
investment if you choose wisely and buy at cheap prices.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.
  #4 (permalink)  
Old August 4th 04, 01:39 AM posted to uk.rec.audio
Trevor Wilson
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Posts: 242
Default Re Valve amps


"StaffBull" wrote in message
...
Thanks for the helpful comments below - another question I have is if I
would leave a valve amp on all the time or switch it off and have to wait
for it to warm up every time I need it?


**ALL power amps should be switched off, until they are required for use.
There are several reasons for this:
* Leaving an amp switched on, accelerates wear and tear on several parts. In
SS amps, this means electrolytic caps. In valve amps, this means valves and
electrolytic caps.
* Leaving the amp switched on, leaves the amp open to line surges and
spikes, which may damage equipment.
* Leaving the amp switched on is not environmentally sensitive.

Tell me again why you would buy an amp, without first listening to it?
Tell my why you think this is a good idea?


--
Trevor Wilson
www.rageaudio.com.au


  #5 (permalink)  
Old August 4th 04, 05:40 AM posted to uk.rec.audio
Stewart Pinkerton
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Posts: 3,367
Default Re Valve amps

On Wed, 04 Aug 2004 01:39:29 GMT, "Trevor Wilson"
wrote:


"StaffBull" wrote in message
...
Thanks for the helpful comments below - another question I have is if I
would leave a valve amp on all the time or switch it off and have to wait
for it to warm up every time I need it?


**ALL power amps should be switched off, until they are required for use.


Hooey.

There are several reasons for this:
* Leaving an amp switched on, accelerates wear and tear on several parts. In
SS amps, this means electrolytic caps. In valve amps, this means valves and
electrolytic caps.


Hooey. If it's not a class A amp, or otherwise warm inside, it puts
less strain on the caps to leave them switched on. Start-up surges are
a major cause of cap failure.

My Audiolab 8000P has been switched on for about eight years, and
works just fine. I don't leave the Krell switched on, because it's a
true class A design, and pulls 300 watts from the wall at idle!

* Leaving the amp switched on, leaves the amp open to line surges and
spikes, which may damage equipment.


Only badly designed equipment, and not everywhere has such crappy
mains that this is an issue.

* Leaving the amp switched on is not environmentally sensitive.


Neither is farting, but I doubt it's a major issue.

Tell me again why you would buy an amp, without first listening to it?
Tell my why you think this is a good idea?


Seems like a bad idea - much like attempting to drive any decent
speaker with a cheap valve amp, when the same money would buy you a
sonically transparent SS amp.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #6 (permalink)  
Old August 4th 04, 01:49 PM posted to uk.rec.audio
Keith G
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Posts: 7,388
Default Re Valve amps


"Stewart Pinkerton" wrote in message
...
On Wed, 04 Aug 2004 01:39:29 GMT, "Trevor Wilson"
wrote:


"StaffBull" wrote in message
...
Thanks for the helpful comments below - another question I have is if

I
would leave a valve amp on all the time or switch it off and have to

wait
for it to warm up every time I need it?


**ALL power amps should be switched off, until they are required for use.


Hooey.



Not hooey - all electrical items (without a built in timer needing stanby
current) should be switched off if not in use, including amplifiers. (Ask
your insurers.....)



My Audiolab 8000P has been switched on for about eight years, and
works just fine. I don't leave the Krell switched on, because it's a
true class A design, and pulls 300 watts from the wall at idle!



Presumably the Krell doesn't suffer from being switched off then? Or does it
take that bit longer to strike an arc.....???

;-)





  #7 (permalink)  
Old August 4th 04, 01:51 PM posted to uk.rec.audio
Mike Gilmour
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Posts: 620
Default Re Valve amps


"Keith G" wrote in message
...

"Stewart Pinkerton" wrote in message
...
On Wed, 04 Aug 2004 01:39:29 GMT, "Trevor Wilson"
wrote:


"StaffBull" wrote in message
...
Thanks for the helpful comments below - another question I have is

if
I
would leave a valve amp on all the time or switch it off and have to

wait
for it to warm up every time I need it?

**ALL power amps should be switched off, until they are required for

use.

Hooey.



Not hooey - all electrical items (without a built in timer needing stanby
current) should be switched off if not in use, including amplifiers. (Ask
your insurers.....)



My Audiolab 8000P has been switched on for about eight years, and
works just fine. I don't leave the Krell switched on, because it's a
true class A design, and pulls 300 watts from the wall at idle!



Presumably the Krell doesn't suffer from being switched off then? Or does

it
take that bit longer to strike an arc.....???

;-)


...with carbon rods.... for home cinema. ;-)


  #8 (permalink)  
Old August 4th 04, 03:49 PM posted to uk.rec.audio
Stewart Pinkerton
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Posts: 3,367
Default Re Valve amps

On Wed, 4 Aug 2004 14:51:57 +0100, "Mike Gilmour"
wrote:


"Keith G" wrote in message
...

"Stewart Pinkerton" wrote in message
...


My Audiolab 8000P has been switched on for about eight years, and
works just fine. I don't leave the Krell switched on, because it's a
true class A design, and pulls 300 watts from the wall at idle!


Presumably the Krell doesn't suffer from being switched off then? Or does it
take that bit longer to strike an arc.....???

;-)

...with carbon rods.... for home cinema. ;-)


I wouldn't recommend Krell AV gear to anyone - overpriced and from a
company that now has a truly **** reputation for customer care. :-(
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #9 (permalink)  
Old August 4th 04, 03:48 PM posted to uk.rec.audio
Stewart Pinkerton
external usenet poster
 
Posts: 3,367
Default Re Valve amps

On Wed, 4 Aug 2004 14:49:18 +0100, "Keith G"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Wed, 04 Aug 2004 01:39:29 GMT, "Trevor Wilson"
wrote:


"StaffBull" wrote in message
...
Thanks for the helpful comments below - another question I have is if

I
would leave a valve amp on all the time or switch it off and have to

wait
for it to warm up every time I need it?

**ALL power amps should be switched off, until they are required for use.


Hooey.


Not hooey - all electrical items (without a built in timer needing stanby
current) should be switched off if not in use, including amplifiers. (Ask
your insurers.....)


Insurers are concerned with fire risk, not capacitor failure. This is
a vexed question among audiophiles, for some mysterious reason, but
out in the real world of industrial electronics, most equipment is
kept permanently powered up. Anything with a valve in it (including
CRTs) shouldn't be permanently powered up, but that's virtually no
real-world equipment nowadays, aside from some radio transmitters.

So, the original poster should switch off his valve amp, but we
sensible folk can leave our class AB SS amps permanently switched on.


My Audiolab 8000P has been switched on for about eight years, and
works just fine. I don't leave the Krell switched on, because it's a
true class A design, and pulls 300 watts from the wall at idle!


Presumably the Krell doesn't suffer from being switched off then? Or does it
take that bit longer to strike an arc.....???


It's been working happily for about fifteen years, but it pretty much
*defines* overengineering! For instance, it's only rated at 50 watts
into 8 ohms, but it delivers 195 watts continuous into 4 ohms, both
channels driven. Basically, I'm just too mean to pay the bill for a
constant 300 watt drain! Naturally, the excess heat isn't a problem in
the UK.....................
--

Stewart Pinkerton | Music is Art - Audio is Engineering
  #10 (permalink)  
Old August 4th 04, 07:57 PM posted to uk.rec.audio
Dave Plowman (News)
external usenet poster
 
Posts: 5,872
Default Re Valve amps

In article ,
Stewart Pinkerton wrote:
Anything with a valve in it (including CRTs) shouldn't be permanently
powered up,


It's not so very long ago that all broadcasting equipment was valve, and
plenty was left powered up 24/7. Indeed, a power failure could result in
lots of replacements after it was resumed.
But that equipment was designed for this task - I'm not convinced el
cheapo valve amps are.

--
*The most common name in the world is Mohammed *

Dave Plowman London SW
To e-mail, change noise into sound.
 




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