How about this one, also get an idea of what NFB does.

Hey, no numbers, no link... is that your suggestion that there is no
reason to go with tubes?

In any case, I really could care less about 'the numbers' except as
they affect headroom and potential damage to my speakers, and primarily
with reference to solid state stuff (underpowered solid-state amps are
more prone to damage speakers than 'overpowered' amps). What I care
about is when I am listening, does the music 'invite me in and demand
my attention?' If it does, then the combination of equipment and source
is successful. If it does not, then the combination is not and needs
work.

I guarantee you I will never have a SE 2A3-based amp, the reason being
that I have vintage radios that require such a tube. Diverting 2A3s to
silly uses where there are other, likely better, options available is
counter to my direct interests. But would I reject any generic of amp
otherwise? Not at all if the results from it pass the first test above.
I listen to a very wide variety of music, from Bluegrass to Baroque,
and from Glass Harmonica and Gregorian Chant to 100% synthesized music.
My goal is that with my eyes closed, I feel like I am sitting in the
music.

So, again, whatever the numbers might suggest, whatever the design
criteria might be, the goal is the same. And if the goal is met, I am
happy.

Peter Wieck
Wyncote, PA

wrote in message
oups.com...
Hey, no numbers, no link... is that your suggestion that there is no
reason to go with tubes?

Well, not for me, but that wasn't the reason for the post. I found a design
that seemed like it ws a hybrid and was stable, but I don't know what the
hell happened. I guees it was tired and I was late.:-) I'll see if I can
find it again and post the link. It was IIRC and there's no guarantee, a
50wpc unit, so better for the super efficient speaker guys.

My apologies.

In any case, I really could care less about 'the numbers' except as
they affect headroom and potential damage to my speakers, and primarily
with reference to solid state stuff (underpowered solid-state amps are
more prone to damage speakers than 'overpowered' amps). What I care
about is when I am listening, does the music 'invite me in and demand
my attention?' If it does, then the combination of equipment and source
is successful. If it does not, then the combination is not and needs
work.

Couldn't agree more. Having sufficinent head room is an absolute
requirement. I don't even consider amps under 100 wpc.



I guarantee you I will never have a SE 2A3-based amp, the reason being
that I have vintage radios that require such a tube. Diverting 2A3s to
silly uses where there are other, likely better, options available is
counter to my direct interests. But would I reject any generic of amp
otherwise? Not at all if the results from it pass the first test above.
I listen to a very wide variety of music, from Bluegrass to Baroque,
and from Glass Harmonica and Gregorian Chant to 100% synthesized music.
My goal is that with my eyes closed, I feel like I am sitting in the
music.

So, again, whatever the numbers might suggest, whatever the design
criteria might be, the goal is the same. And if the goal is met, I am
happy.

Peter Wieck
Wyncote, PA

My goal is to have enough power so that my amp never clips, and it must have
flat response and no audible noise or distortion of any kind.

Eventually, I'm going to pick up a pair of the new Behringer A500 reference
amps and bridge them to mono and never have to worry about clipping again.
With 500 wpc in my listening room, I'm reasonably sure I would blow the
speakers or my ears before I ran out of power.

At $179.00 per amp, they are IMO, the deal of the century.
You can look at tehm he
http://www.zzounds.com/item--BEHA500

160wpc @8 ohms
230 wpc @ 4 ohms
500 watts bridged mono
Distortion 0.01%
10 Hz- 25 kHz +0/-1dB
Noise -10dB @ 1kHz
Amplificaton 25x (28dB)
Convection cooling
Protection against short circuit and overload
Push pull class AB
18.5 lbs.

Maybe I'll try just one first and if it works as it should get the second.
If it doesn't seem good enough for main speakers it should certainly make a
good subwoofer amp and still be a bargain.

said:

Eventually, I'm going to pick up a pair of the new Behringer A500 reference
amps and bridge them to mono and never have to worry about clipping again.
With 500 wpc in my listening room, I'm reasonably sure I would blow the
speakers or my ears before I ran out of power.


Could you list the sensitivity and nominal impedance of your main
speakers, Mike?

Oh, and the size of your listening room?

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

wrote:

snip
I guarantee you I will never have a SE 2A3-based amp, the reason being
that I have vintage radios that require such a tube. Diverting 2A3s to
silly uses where there are other, likely better, options available is
counter to my direct interests.

Peter,

You're missing out if you've never heard a SE 2A3 done right.
There are options other than the use of vintage 2A3s. Sovtek makes a
very nice single plate 2A3 which is quite reasonably priced (IMO). KR
makes a 2A3 as well, but it's considerably more costly. I believe
Emission Labs also makes a 2A3 as well as a 45. Given your musical
tastes, you might like a SE amp.

Happy Holidays!

Raymond

But would I reject any generic of amp
otherwise? Not at all if the results from it pass the first test above.
I listen to a very wide variety of music, from Bluegrass to Baroque,
and from Glass Harmonica and Gregorian Chant to 100% synthesized music.
My goal is that with my eyes closed, I feel like I am sitting in the
music.

So, again, whatever the numbers might suggest, whatever the design
criteria might be, the goal is the same. And if the goal is met, I am
happy.

Peter Wieck
Wyncote, PA

wrote in message
nk.net...
How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


--
Trevor Wilson
www.rageaudio.com.au

"Trevor Wilson" said:


How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


One must assume that by the simple designation "NFB", most people, not
well versed in audio electronics, mean loop or global negative feed
back, you will note.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

On Mon, 19 Dec 2005 21:44:23 +0100, Sander deWaal
wrote:

"Trevor Wilson" said:


How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


One must assume that by the simple designation "NFB", most people, not
well versed in audio electronics, mean loop or global negative feed
back, you will note.

SS amps with global feedback only in fact have it at low frequencies.
The dominant pole transfers the feedback to local feedback around the
voltage amplifier as the frequency rises. It is impossible to separate
local and global feedback in any amplifier.

d

Pearce Consulting
http://www.pearce.uk.com

(Don Pearce) said:

It is impossible to separate
local and global feedback in any amplifier.


In schematic terms, it sure is possible.
In practice, you are right.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

"Sander deWaal" wrote in message
...
"Trevor Wilson" said:


How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


One must assume that by the simple designation "NFB", most people, not
well versed in audio electronics, mean loop or global negative feed
back, you will note.

**One could argue that, unless they learn the ramifications of what they
speak of, they shouldn't bother getting involved in areas they don't
understand. Fundamentally, there are many different NFB schemes, all of
which achieve the same objective (more or less). There will, of course, be
slight differences, hence the preference by many listeners to one scheme or
the other.


--
Trevor Wilson
www.rageaudio.com.au

Specifications:

Power Output Ratings:Less than 0.25% total harmonic distortion at any
power level up to 200 watts continuous average power per channel into 8
ohms (300 watts per channel into 4 ohms; 100 watts per channel into 16
ohms) at any frequency between 20 Hz and 20 KHz with both channels
driven. Distortion reduces at lower levels.

Power at Clipping, single channel, 2500 Hz, less than 1% distortion:

235 watts @ 8 ohms;
350 watts @ 4 ohms;
135 watts @ 16 ohms.
Intermodulation Distortion: Less than 0.1% at any power level up to 200
watts rms per channel into 8 ohms with any combination of test
frequencies. Distortion reduces at lower power levels. Typically less
than 0.03%.

Half-Power Bandwidth: 100 watts per channel at less than 0.25% total
harmonic distortion from 5 Hz to 35 KHz into 8 ohms.

Frequency Response:

+0, -1 dB, 8 Hz - 50 KHz @ 1 watt into 8 ohms;
±0.5 dB, 20 Hz - 20 KHz @ 200 watts.

Hum and Noise: Greater than 95 dB below rated output, full spectrum.
Greater than 100 dB below rated output, 20 Hz - 20 KHz.

Input:

Normal: 50,000 ohm load;
Control By-Pass: 20,000 ohm load;
1.6 volts for 200 watts @ 8 ohms.

Slewing Rate: 8 volts per microsecond.

Damping Factor:

Greater than 80 to 1 KHz into 8 ohms;
Greater than 30 to 10 KHz into 8 ohms.

Channel Separation: Greater than 60 dB by IHF standards.

Connectors: Inputs: phono jacks. Outputs: Color coded 3-way binding
posts with standard 3/4" spacing.

Dimensions: 19" wide; 14" deep; 7" high.

Weight: Shipping weight 59 lbs/27 kilos. Net weight 53 lbs/25 kilos.

Power Consumption: 120 VA quiescent; 17 amps maximum; 50/60 Hz, 120/240
VAC.

Above are the specifications for my front-line amp, purchased brand new
in 1978 for $212 inclusive of tax, so easily three times that in 2005
dollars. It is pretty much capable of driving about anything, and is
stable down to a nominal 2-ohm speaker load (which as you all know
comes to much less than 2 ohms as a dynamic load. My front-line
speakers are nicely cleaned-up AR3as (nominal 4-ohm) (the treble &
mid-range controls are bypassed, for example). The listening area is
rather small by these standards, about 12 x 16 feet, 9'-6" ceiling.
four windows, fireplace and french doors, 100 YO plaster walls &
ceiling and hardwood floor, usual furniture, Victorian antique mostly,
and a Turkish 400-knot carpet on the floor. No standing waves.

My most efficient speakers are a pair of AR M6s, (
http://www.arsenal.net/speakers/ar/AR-holograms.pdf ) rated at 90dB
SPL @ 1Meter for 2.83V input. The 3as have more low-end, but need a
bunch more power.

The 'upstairs' stereo(s) are where the experimentation takes place,
alternately to a several different pairs of AR speakers (another pair
of 3as with the controls intact, M5, 4x, Dynaco A25, and Boston
Acoustics available, with EPI, ESS, and a whole bunch of others through
from time-to-time. Electronics include AR Receiver, AR amp, Dynaco SS
amps (several), ST-70. Scott LK-150, Revox A78, HK Citation stuff, and
no end of various tuners from Scott, AR, Dynaco and several others,
tube and SS, not to mention what 'passes through'. That room is
actually bigger, nearly 16 feet square, and more lively (less
furniture), and with sufficient angles as to avoid standing waves also.


I am beginning to get a bit more into tubes, the LK-150 is what started
me down that road... 'everybody has an ST-70' about cover the way
things are around here, and so I found nothing remarkable about it. But
it is very hard to step back from the luxury of Lots-O-Power.

Peter Wieck
Wyncote, PA

"Trevor Wilson" wrote in message
...

wrote in message
nk.net...
How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


Never tried to imply they didn't Trevor. It just gets spelled out very
nicely in the article I refernced.

"Sander deWaal" wrote in message
...
said:

Eventually, I'm going to pick up a pair of the new Behringer A500
reference
amps and bridge them to mono and never have to worry about clipping again.
With 500 wpc in my listening room, I'm reasonably sure I would blow the
speakers or my ears before I ran out of power.


Could you list the sensitivity and nominal impedance of your main
speakers, Mike?

Oh, and the size of your listening room?
You're just going to tell me it's more power than I need, which I already
know.
I just like the idea of having more reserve power than I will ever need,
thus guaranteeing no clipping, ever.

For a subwoofer that's rated at 700 watts a 500 watt amp is certainly not
overkill.

wrote in message
nk.net...

"Trevor Wilson" wrote in message
...

wrote in message
nk.net...
How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


Never tried to imply they didn't Trevor. It just gets spelled out very
nicely in the article I refernced.

**Which article? I saw no reference.


--
Trevor Wilson
www.rageaudio.com.au

Don Pearce wrote:

On Mon, 19 Dec 2005 21:44:23 +0100, Sander deWaal
wrote:

"Trevor Wilson" said:


How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


One must assume that by the simple designation "NFB", most people, not
well versed in audio electronics, mean loop or global negative feed
back, you will note.

SS amps with global feedback only in fact have it at low frequencies.
The dominant pole transfers the feedback to local feedback around the
voltage amplifier as the frequency rises. It is impossible to separate
local and global feedback in any amplifier.

Hi Don,

could you elaborate on that point ?

The last SS amp I designed has 2 voltage gain stages which both have local
feedback. The loop is finally closed around them all. This was dome
specifically to design for stability and predictable performance.

In what way are you suggesting they can't be separated.

Both stages are pole-zero compensated btw - specifically targeting phase
margin - obviously 2 poles wouldn't be acceptable. :-)

Graham

Raymond Koonce wrote:
wrote:

snip
I guarantee you I will never have a SE 2A3-based amp, the reason being
that I have vintage radios that require such a tube. Diverting 2A3s to
silly uses where there are other, likely better, options available is
counter to my direct interests.

The more people that build 2A3 amps the more likely it will be for
them to be made in the future. In fact there are new 2A3s available and
they are very good, at least some are. Also, I must admit if you want
a triode smaller than a 211 the single plate 2A3 is probably the best
one to use.

"Trevor Wilson" wrote in message
...

wrote in message
nk.net...

"Trevor Wilson" wrote in message
...

wrote in message
nk.net...
How about this one, also get an idea of what NFB does.

**ALL amplifiers use NFB. Every single one.


Never tried to imply they didn't Trevor. It just gets spelled out very
nicely in the article I refernced.

**Which article? I saw no reference.


That's the problem, I found it late last night and somehow forgot to paste
it.
I've been searching for it again but so far no luck. I thought it would be
of interest to this NG as it used both tubes and transistors and NFB was
explained.

If I find it again I will post the link, the problem is that I can't
remember what I was searching for in the first place.

On Mon, 19 Dec 2005 23:50:30 GMT, wrote:


"Sander deWaal" wrote in message
.. .
said:

Eventually, I'm going to pick up a pair of the new Behringer A500
reference
amps and bridge them to mono and never have to worry about clipping again.
With 500 wpc in my listening room, I'm reasonably sure I would blow the
speakers or my ears before I ran out of power.


Could you list the sensitivity and nominal impedance of your main
speakers, Mike?

Oh, and the size of your listening room?
You're just going to tell me it's more power than I need, which I already
know.
I just like the idea of having more reserve power than I will ever need,
thus guaranteeing no clipping, ever.

For a subwoofer that's rated at 700 watts a 500 watt amp is certainly not
overkill.

Actually, he's quite likely to tell you that it's not enough. B&W have
a multichannel demo room at the factory, which uses 800 series
speakers all round. They had to junk the Krell 300 that was driving
the centre speaker, because it kept *audibly* clipping.........
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message
...
On Mon, 19 Dec 2005 23:50:30 GMT, wrote:


"Sander deWaal" wrote in message
. ..
said:

Eventually, I'm going to pick up a pair of the new Behringer A500
reference
amps and bridge them to mono and never have to worry about clipping
again.
With 500 wpc in my listening room, I'm reasonably sure I would blow the
speakers or my ears before I ran out of power.


Could you list the sensitivity and nominal impedance of your main
speakers, Mike?

Oh, and the size of your listening room?
You're just going to tell me it's more power than I need, which I already
know.
I just like the idea of having more reserve power than I will ever need,
thus guaranteeing no clipping, ever.

For a subwoofer that's rated at 700 watts a 500 watt amp is certainly not
overkill.

Actually, he's quite likely to tell you that it's not enough. B&W have
a multichannel demo room at the factory, which uses 800 series
speakers all round. They had to junk the Krell 300 that was driving
the centre speaker, because it kept *audibly* clipping.........
--

Sander asnd I have had this conversation before, and he thinks I'm wanting
more power than neccessary. At least that's how I recall it.