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GerryE123 GerryE123 is offline
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Default Tube Amp - Autoformer - Speakers

Hi:

I recently acquired 4-ohm speakers and re-wired my SE 45 amp to use the
4-ohm OPT tap. There's an autoformer on the home audio market that
effectively multiplies the load your amp "sees" by 2x, 3x or 4x.

Is it possible or even likely, that my system could sound "better" using
this autoformer and re-wiring the OPT impedance tap to 8 or 16 ohms? I
realize this question may be more complex than it sounds (many variables).

I have a VERY simple, but high quality system. The thought of running my
signal through a large coil of wire (the autoformer) is not that appealing,
but if it could sound better...

Gerry
P.S. I know I could just add a resistor, but that has it own set of
problems.




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Patrick Turner Patrick Turner is offline
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Default Tube Amp - Autoformer - Speakers



GerryE123 wrote:

Hi:

I recently acquired 4-ohm speakers and re-wired my SE 45 amp to use the
4-ohm OPT tap. There's an autoformer on the home audio market that
effectively multiplies the load your amp "sees" by 2x, 3x or 4x.

Is it possible or even likely, that my system could sound "better" using
this autoformer and re-wiring the OPT impedance tap to 8 or 16 ohms? I
realize this question may be more complex than it sounds (many variables).

I have a VERY simple, but high quality system. The thought of running my
signal through a large coil of wire (the autoformer) is not that appealing,
but if it could sound better...

Gerry
P.S. I know I could just add a resistor, but that has it own set of
problems.


A company or bloke runs a business called Zero Impedance and makes
toroidal transformers rated for maybe 100W for allowing a 4 ohm speaker
to appear to an amp as a 16 ohms speaker. Or vice versa, something 16
ohms can be made to appear as 4 ohms, 8 ohms, whatever.

I measured one of these and found bandwidth to be extremely wide and
distortion far less than that occurng in the tube amp concerned
and winding losses to be negligible.
Two guys here have such transformers to optimise the load match between
amp and speakers.

Both said that if they used the transformer to make a 4 ohms speaker
appear to the amp as an 8 ohm or 12 ohm load, the music sounded better.
That's because the distortion becomes lower and damping factor becomes
higher.

The down side is that they run out of headroom at a lower level of
*power*. With most music this doesn't matter if the amp has a high
enough ceiling, but an SE 45 amp hasn't got that unless you have horn
loaded speakers.

To get the best sound from SET, you really do have to know what the
anode load is and do the required loadline analysis to make sure what is
the right load for symetrical clipping. Using a load below this critical
load breeds much more distortion and using a load above it
brings less distortion. But either side of the critical load for
symetrical clipping, SE power ceilings diminish.

Ya gotta know what ya doin.

Patrick Turner.
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Andre Jute[_2_] Andre Jute[_2_] is offline
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Default Tube Amp - Autoformer - Speakers

On Dec 9, 2:35*pm, "GerryE123" wrote:
Hi:

I recently acquired 4-ohm speakers and re-wired my SE 45 amp to use the
4-ohm OPT tap. *There's an autoformer on the home audio market that
effectively multiplies the load your amp "sees" by 2x, 3x or 4x.

Is it possible or even likely, that my system could sound "better" using
this autoformer and re-wiring the OPT impedance tap to 8 or 16 ohms? *I
realize this question may be more complex than it sounds (many variables)..

I have a VERY simple, but high quality system. *The thought of running my
signal through a large coil of wire (the autoformer) is not that appealing,
but if it could sound better...

Gerry
P.S. I know I could just add a resistor, but that has it own set of
problems.


Gerry: You need a graphic to centre your output on the transfer curve,
and to position the transfer curve correctly. Patrick explains why
this is necessary; in addition there is grid current to consider, if
you're using a class A amp. On my netsite there are several chapters
about all this but for a quick intro and a look at how the Eb-Ia-Eg
curves work, with graphs you can adapt to your 45, try this KISS 112:
Choosing an operating point for a new design -- or a new load
reflected impedance load. It is at :
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm

Andre Jute
Tubes tend to make people believe in a god, and SS leads them to the
devil. -- Patrick Turner

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keithr keithr is offline
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Default Tube Amp - Autoformer - Speakers

Patrick Turner wrote:

GerryE123 wrote:
Hi:

I recently acquired 4-ohm speakers and re-wired my SE 45 amp to use the
4-ohm OPT tap. There's an autoformer on the home audio market that
effectively multiplies the load your amp "sees" by 2x, 3x or 4x.

Is it possible or even likely, that my system could sound "better" using
this autoformer and re-wiring the OPT impedance tap to 8 or 16 ohms? I
realize this question may be more complex than it sounds (many variables).

I have a VERY simple, but high quality system. The thought of running my
signal through a large coil of wire (the autoformer) is not that appealing,
but if it could sound better...

Gerry
P.S. I know I could just add a resistor, but that has it own set of
problems.


A company or bloke runs a business called Zero Impedance and makes
toroidal transformers rated for maybe 100W for allowing a 4 ohm speaker
to appear to an amp as a 16 ohms speaker. Or vice versa, something 16
ohms can be made to appear as 4 ohms, 8 ohms, whatever.

I measured one of these and found bandwidth to be extremely wide and
distortion far less than that occurng in the tube amp concerned
and winding losses to be negligible.
Two guys here have such transformers to optimise the load match between
amp and speakers.

Both said that if they used the transformer to make a 4 ohms speaker
appear to the amp as an 8 ohm or 12 ohm load, the music sounded better.
That's because the distortion becomes lower and damping factor becomes
higher.


Exactly how does the damping factor become higher? If you use say the 8
ohm tap on the OPT, then an autotransformer to step this down to 4 ohms,
provided both transformers do what they say, nothing is changed from
using the 4 ohm tap in the first place. The output stage sees exactly
the same load impedance and the damping factor is unchanged because the
speaker still sees the same source impedance.

The down side is that they run out of headroom at a lower level of
*power*. With most music this doesn't matter if the amp has a high
enough ceiling, but an SE 45 amp hasn't got that unless you have horn
loaded speakers.

To get the best sound from SET, you really do have to know what the
anode load is and do the required loadline analysis to make sure what is
the right load for symetrical clipping. Using a load below this critical
load breeds much more distortion and using a load above it
brings less distortion. But either side of the critical load for
symetrical clipping, SE power ceilings diminish.

Ya gotta know what ya doin.


These transformers may be fine if you do not have an output tap to match
the speakers, but it is hard to see what they bring to the table if the
correct tap is available.

Keith
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BretLudwig BretLudwig is offline
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Default Tube Amp - Autoformer - Speakers

Simply put using an autoformer AFTER the opt is a bad idea.

A single ended 45 simply does not have enough power for good full range
high fidelity reproduction of any but the most snot-squashed musical
content at any appreciable volume. A 300B or a larger beam power tetrode
operated triode strapped is about the smallest tube that even passes the
most cursory examination. Now if you are using multi-amping a single 45
may work for a treble driver but that's another matter.

That said-if the opt does not have the right taps for the speaker get a
new opt.

Autoformers are essentially simple devices. They are just a big tapped
inductor, in essence. Any toroid winding shop with a Gorman can wind you
an audio autoformer of any feasible ratio for the price of the core and
wire plus maybe twenty bucks labor. McIntosh's C-core versions are quite
pricey if bought as spares but junk SS Mc amps do become available here
and again.

--
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Phil Allison Phil Allison is offline
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Default Tube Amp - Autoformer - Speakers


"Keithr"
" The Turneroid Menace "

Both said that if they used the transformer to make a 4 ohms speaker
appear to the amp as an 8 ohm or 12 ohm load, the music sounded better.
That's because the distortion becomes lower and damping factor becomes
higher.
Exactly how does the damping factor become higher? If you use say the 8
ohm tap on the OPT, then an autotransformer to step this down to 4 ohms,
provided both transformers do what they say, nothing is changed from using
the 4 ohm tap in the first place.



** Contradicts the proposition you are commenting on.

Which was about deliberately UNDERLOADING the amplifier.


The output stage sees exactly the same load impedance


** Not when the speaker remains the same - pal.


and the damping factor is unchanged because the speaker still sees the
same source impedance.


** Still wrong on both counts.


These transformers may be fine if you do not have an output tap to match
the speakers, but it is hard to see what they bring to the table if the
correct tap is available.



** PT never said they did -

the ****wit OP suggested that nonsense.



....... Phil





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Patrick Turner Patrick Turner is offline
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Default Tube Amp - Autoformer - Speakers



Keithr wrote:

Patrick Turner wrote:

GerryE123 wrote:
Hi:

I recently acquired 4-ohm speakers and re-wired my SE 45 amp to use the
4-ohm OPT tap. There's an autoformer on the home audio market that
effectively multiplies the load your amp "sees" by 2x, 3x or 4x.

Is it possible or even likely, that my system could sound "better" using
this autoformer and re-wiring the OPT impedance tap to 8 or 16 ohms? I
realize this question may be more complex than it sounds (many variables).

I have a VERY simple, but high quality system. The thought of running my
signal through a large coil of wire (the autoformer) is not that appealing,
but if it could sound better...

Gerry
P.S. I know I could just add a resistor, but that has it own set of
problems.


A company or bloke runs a business called Zero Impedance and makes
toroidal transformers rated for maybe 100W for allowing a 4 ohm speaker
to appear to an amp as a 16 ohms speaker. Or vice versa, something 16
ohms can be made to appear as 4 ohms, 8 ohms, whatever.

I measured one of these and found bandwidth to be extremely wide and
distortion far less than that occurng in the tube amp concerned
and winding losses to be negligible.
Two guys here have such transformers to optimise the load match between
amp and speakers.

Both said that if they used the transformer to make a 4 ohms speaker
appear to the amp as an 8 ohm or 12 ohm load, the music sounded better.
That's because the distortion becomes lower and damping factor becomes
higher.


Exactly how does the damping factor become higher? If you use say the 8
ohm tap on the OPT, then an autotransformer to step this down to 4 ohms,
provided both transformers do what they say, nothing is changed from
using the 4 ohm tap in the first place. The output stage sees exactly
the same load impedance and the damping factor is unchanged because the
speaker still sees the same source impedance.


Suppose a tube amp has a DF= 8 at the outlet labelled "8 ohms"

This would mean the Rout of the amp is 1 ohm.

With 4 ohms used at this outlet, the DF is only 4.

With a 2 : 1 impedance matching transformer with turn ratio of 1 : 0.7,
the 4 ohm speaker is made to look like an 8 ohm speaker load at the amp
and DF is raised to 8. If the ZR = 4:1 with a TR = 2:1, the 4 ohm
speaker becomes a 16 ohm speaker and DF = 16.

Suppose you need 2.83V for 1 watt of SPL with an 8 ohm load at the amp.

With a 4 ohm speaker of the same sensitivity you'd need only 2V to get
the same sensitivty, but there will be some increase in THD.
If you make the 4 ohms speaker look like a 16 ohm speaker, the amp needs
to make 4V to get that watt of sound.
Usually the THD will be a bit lower because of the higher load despite
having to make more voltage.
But you can see that you'll run out of voltage headroom sooner with a
step down voltage transformer.
if you step up the voltage, you'll run out of current headroom.

More info at

http://www.zeroimpedance.com/faq.html



The down side is that they run out of headroom at a lower level of
*power*. With most music this doesn't matter if the amp has a high
enough ceiling, but an SE 45 amp hasn't got that unless you have horn
loaded speakers.

To get the best sound from SET, you really do have to know what the
anode load is and do the required loadline analysis to make sure what is
the right load for symetrical clipping. Using a load below this critical
load breeds much more distortion and using a load above it
brings less distortion. But either side of the critical load for
symetrical clipping, SE power ceilings diminish.

Ya gotta know what ya doin.


These transformers may be fine if you do not have an output tap to match
the speakers, but it is hard to see what they bring to the table if the
correct tap is available.


Most modern tube amps are configured to make their maximum clipping
power when an 8 ohm load is connected to what is labelled an 8 ohm
outlet. Some have a 4 ohm outlet which is usually a tap at 0.7 times the
OPT secondary turns meant for 8 ohms.

So if the OPT sec turns were 100t for 8 ohms, the 4 ohm outlet is at
70t. If you wanted a match to 2 ohms, the tap would be at the 50t point
or what is the CT of the 8 ohm winding.

Unfortunately, most "8ohm speakers" are often only 8 at maybe 1khHz but
have a big dip in Z between say 100Hz and 300Hz because of the crossover
filters between bass and midrange which is the middle of the band where
most audio music energy is located. Any tube amp which is configured to
give maximum PO at 8 ohms tends to have very poor performance when 4
ohms is connected so if there is "4 ohm" labelled outlet, ie, a tap for
the better load match, it should always be used with an 8 ohm speaker.

Most modern tube amps are PP amps set up so their makers can claim a
huge power level to get sales.

So we will see where someome has 2 x EL34 but PO = 50 watts, class AB1.
If you test many PP EL34 amps and plot the PO against load at 2% THD,
you get a peak in absolute maximum sine wave power at the onset of
clipping (2% thd) maybe at 50 watts. At whatever load is required to
produce this PO the amount of class A in the total AB PO is very small,
a few watts at most, and THD is high at all levels.

A sensible Hi-Fi amp designer will make the maximum PO of say 50 watts
be produced when the load at the OPT secondary is 2.5 ohms.
The OPT turn ratio is selected to give the load match so that 2.5 ohms
is where maximum PO is produced and loads either side of 2.5 ohms have
less power at clipping. When 8 ohms is used in such an amp, you'll find
that max PO might only be 30W class AB. But the DF will be high and the
THD low at all levels and the amount of class A = 12 watts before the
action becomes class AB. If 16 ohms is connected to this amp you'll find
only 20 watts might be produced but its all class A1 power, and if 20
watts is more than enough PO for most folks listening levels then that
20Watts has a chance of sounding very nice because DF is high, is low.

With many amps made by major brandnames, ARC, Manley Labs, the music
benefits with an impedance matching tranny to achieve what the makers
should have provided in their creations, ie, a better match for Hi-Hi,
not a load match which you'd only use if you were making a PA amp where
loudness is the most important consideration and not fidelity.

Many modern tube amps are merely PA amps with moderate global NFB.
Bloody awful. No Finesse. Sold by promoting watts, not what they do
with music.

When you consider SE amps with a lone 45, 2A3, 300B etc, the load
matching becomes even more critical than that for a quasi class B PA amp
with lots of power ability, if you have low sensitivity speakers.

With high sensitivity horn loaded speakers then 4 watts from a 2A3 is
more than enough. But for best sound you still need to load match
properly. I've devoted some of my web pages to load matching but the
message doesn't get through easily.
Load matching is like using the right gearbox ratio to match an engine
to wheel speed so the vehicle can be driven up a hill with the family
and luggage without the engine stalling. Or its like riding a bicycle
using the right gearing.

One of the very worst offenders in brandame amps where they got the load
matching appallingly wrong was in a CR Developments PP amp model known
as the "Woodham". http://www.crdevelopments.com/ I had one here 18mths
ago for a reapir/rebuild. This utter POS had a reflected load anode to
anode = 3.2k, but with a 600V anode supply, and a poor copy of a
McIntosh output stage using small toroidal OPTs. It cooked output tubes
regularly. THD was appalling. DF was ****house, and the only good thing
was the metalwork.
I totally stripped it out and re-wired it to my own design and lowered
the B+ to 420V with a choke input B+ filter, then adjusted the output
transformer outlets so there was only a 4 ohm load match, ie, the RLa-a
was 6.4k instead of 3.2k, and the PO was the same as the original amp
but THD far lower, DF far higher, and no more fried tubes every month.

Many brandname designers have completely forgotten how to design and
manufacture a decent tube amp. CR Developments is such a brandame.
Silk Amps from Thailand is another brand, quite a few made in China,
Audion is another, labelled "Made in the UK" like the CR, but utter
crap,
and made to match the worst from China in a very determined manner. The
fuctards making all this torrent of crap give tube amps a bad name and
cause untold grief amoung music listeners. I hope they all go broke
during these hard times of economic hardship.


Patrrick Turner.
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Patrick Turner Patrick Turner is offline
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Phil Allison wrote:

"Keithr"
" The Turneroid Menace "

Both said that if they used the transformer to make a 4 ohms speaker
appear to the amp as an 8 ohm or 12 ohm load, the music sounded better.
That's because the distortion becomes lower and damping factor becomes
higher.
Exactly how does the damping factor become higher? If you use say the 8
ohm tap on the OPT, then an autotransformer to step this down to 4 ohms,
provided both transformers do what they say, nothing is changed from using
the 4 ohm tap in the first place.


** Contradicts the proposition you are commenting on.

Which was about deliberately UNDERLOADING the amplifier.

The output stage sees exactly the same load impedance


** Not when the speaker remains the same - pal.

and the damping factor is unchanged because the speaker still sees the
same source impedance.


** Still wrong on both counts.

These transformers may be fine if you do not have an output tap to match
the speakers, but it is hard to see what they bring to the table if the
correct tap is available.


** PT never said they did -

the ****wit OP suggested that nonsense.

...... Phil


If one uses a step down matching tranny after an amp you are
"deliberately UNDERLOADING the amplifier" as you say.

But the load match you may actually get when you do this might in fact
be a better one for fidelity for the power you want.

There isn't anything wrong with using a 16 ohm speaker plugged into the
"4 ohm" labelled output of a tube amp if the levels obtained are high
enough, and assuming that the makers have made their amp unconditionally
stable, ie, it won't oscillate with the higher value ohm load.

Many tube amps oscillate at LF and perhaps HF with a high value load, or
no load connected, ie, with a load equal to an infinite number of ohms,
ie sitting there without speakers plugged in.

Most tube amps will produce better fidelity at least for the first few
watts of power if the load value is higher than the outlet label says.
This is because the output tubes are working in a more linear manner
with more class A1, output tube voltage gain is higher, and thus the
amount of applied global NFB is greater, because the amount of applied
NFB depends on the open loop gain. The higher load also means the
leakage inductance causes less HF attenuation and the damping factor is
raised.

Many listeners have heard better sound using Zero Impedance transformers
even when the load match was OK in theory; ie, when the load value was
raised higher than "it should be" and the load is "underpowered", the
music sounded better, and so it should have because the THD was lower,
and DF higher. The "underpowered" load match means less maximum PO is
available abd in SE amps it means clipping is asymetrical because the
wave clips onj one side due to grid current before cut off occurs. But
who cares how the amp clips if there is **enough** power before clipping
occurs?

Patrick Turner.
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John Byrns John Byrns is offline
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Default Tube Amp - Autoformer - Speakers

In article ,
Patrick Turner wrote:

Many listeners have heard better sound using Zero Impedance transformers
even when the load match was OK in theory; ie, when the load value was
raised higher than "it should be" and the load is "underpowered", the
music sounded better, and so it should have because the THD was lower,
and DF higher. The "underpowered" load match means less maximum PO is
available abd in SE amps it means clipping is asymetrical because the
wave clips onj one side due to grid current before cut off occurs. But
who cares how the amp clips if there is **enough** power before clipping
occurs?


Not to mention that asymetrical clipping is more musical than symetrical
clipping.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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Patrick Turner Patrick Turner is offline
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Default Tube Amp - Autoformer - Speakers



John Byrns wrote:

In article ,
Patrick Turner wrote:

Many listeners have heard better sound using Zero Impedance transformers
even when the load match was OK in theory; ie, when the load value was
raised higher than "it should be" and the load is "underpowered", the
music sounded better, and so it should have because the THD was lower,
and DF higher. The "underpowered" load match means less maximum PO is
available abd in SE amps it means clipping is asymetrical because the
wave clips onj one side due to grid current before cut off occurs. But
who cares how the amp clips if there is **enough** power before clipping
occurs?


Not to mention that asymetrical clipping is more musical than symetrical
clipping.


Clipping of transient peaks in music signals which have not been
compressed may not change the nature of the music much except to reduce
the sound of the recording to a lowest common denominator everyone has
been forced to get used to; hence we don't notice the change; until we
attend a live concert, and *then* we notice a big change allright.
And its remarkable how much clipping you can have on peaks before anyone
notices, symetrical or assymetrical.
I have often heard audio with clipping to one side of the signal and it
sounds bad if the clipping digs deep enough, and not at all musical
imho. In AM radios its a common fault to find clipping of the detected
audio waves after the detector. Once you trim values or change the
circuit to make the detector linear, voila, music, and despite the
limitations of the IF amp and audio amp and poor speaker in the radio.


Today, many recordings have been compressed a lot, and usually
compressed symetrically, which means you've added large amounts of 3H,5H
,7H,9H to waves whose crests have been flattened. A lot of pop music
recordings show that the bass waves are quite clipped and compressed.

But all the people I know never run the levels anywhere near clipping of
anything any time. Most run less than 40W per channel and speakers with
88dB/W/M sensitivity. They ain't deaf.

Patrick Turner.


--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/



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GerryE123 GerryE123 is offline
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Default Tube Amp - Autoformer - Speakers

A belated thank you to everyone who responded, especially Patrick and Andre!
I knew there's more to this than a simple answer. Also, some of the
technical stuff is above my knowledge, but at least I have a better
understanding of it.

Patrick, you were correct, I was referring to the Speltz Zero Impedance
autoformers:

http://www.zeroimpedance.com/Zero-New.html

I could ignore the technical cosiderations and just take Speltz up on his
60-day free trial.

Gerry




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John Byrns John Byrns is offline
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Default Tube Amp - Autoformer - Speakers

In article ,
"GerryE123" wrote:

A belated thank you to everyone who responded, especially Patrick and Andre!
I knew there's more to this than a simple answer. Also, some of the
technical stuff is above my knowledge, but at least I have a better
understanding of it.

Patrick, you were correct, I was referring to the Speltz Zero Impedance
autoformers:

http://www.zeroimpedance.com/Zero-New.html

I could ignore the technical cosiderations and just take Speltz up on his
60-day free trial.


It's not obvious to me precisely what "technical cosiderations" you are talking
about, the "technical cosiderations" are straight forward enough. All that
matters in the end is how it sounds, so I say go for it and give them a try, and
be sure and let us all know what effect they have on the sound.

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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GerryE123 GerryE123 is offline
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Default Tube Amp - Autoformer - Speakers


"John Byrns" wrote in a message:

It's not obvious to me precisely what "technical cosiderations" you are
talking
about, the "technical cosiderations" are straight forward enough. All
that
matters in the end is how it sounds, so I say go for it and give them a
try, and
be sure and let us all know what effect they have on the sound.

Regards,
John Byrns


Actually John, that was the point I was trying to make. Instead of
"technical considerations", substitute "theoretical considerations". In the
end, they don't matter, it's the sound that matters.

Let's see, there are three autoformer taps and my OPT has three taps so
that's 9 trials plus three without the autoformer. That's a total of 12
unless I eliminate some out of hand (there's those damn theoretical
considerations again).

Gerry


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John Byrns John Byrns is offline
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Default Tube Amp - Autoformer - Speakers

In article ,
"GerryE123" wrote:

"John Byrns" wrote in a message:

It's not obvious to me precisely what "technical cosiderations" you are
talking
about, the "technical cosiderations" are straight forward enough. All
that
matters in the end is how it sounds, so I say go for it and give them a
try, and
be sure and let us all know what effect they have on the sound.

Regards,
John Byrns


Actually John, that was the point I was trying to make. Instead of
"technical considerations", substitute "theoretical considerations". In the
end, they don't matter, it's the sound that matters.

Let's see, there are three autoformer taps and my OPT has three taps so
that's 9 trials plus three without the autoformer. That's a total of 12
unless I eliminate some out of hand (there's those damn theoretical
considerations again).


Without counting them I would guess there are at least 50 distinct ways of
connecting the autotransformer that provide unique impedance ratios. Together
with the three taps on the OPT that gives something in excess of 100 trials to
be made, sounds like cheap fun. I'm not sure how you could eliminate any out of
hand, even taking those "damn theoretical considerations" into account?

--
Regards,

John Byrns

Surf my web pages at, http://fmamradios.com/
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Patrick Turner Patrick Turner is offline
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Default Tube Amp - Autoformer - Speakers



GerryE123 wrote:

A belated thank you to everyone who responded, especially Patrick and Andre!
I knew there's more to this than a simple answer. Also, some of the
technical stuff is above my knowledge, but at least I have a better
understanding of it.

Patrick, you were correct, I was referring to the Speltz Zero Impedance
autoformers:

http://www.zeroimpedance.com/Zero-New.html

I could ignore the technical cosiderations and just take Speltz up on his
60-day free trial.

Gerry

Two guys here in Oz bought Zero Z trannies and are happy.
Not necessarily because they got more maximum power but because they
were prepared to trade away the maximum power rating at clipping for
more class A power within the first 10 watts with higher amp load, thus
getting better DF and lower THD/IMD.

Now ppl are thinking twice because our aud is now only usd $0.66c

The US has troubles with sub-prime, our dollar crashes. Queer.

But the Zero's work OK. Anyone could wind their own if they wanted to.
Its all thick wire on big cores and not too many turns.

Patrick Turner.


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Patrick Turner Patrick Turner is offline
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GerryE123 wrote:

"John Byrns" wrote in a message:

It's not obvious to me precisely what "technical cosiderations" you are
talking
about, the "technical cosiderations" are straight forward enough. All
that
matters in the end is how it sounds, so I say go for it and give them a
try, and
be sure and let us all know what effect they have on the sound.

Regards,
John Byrns


Actually John, that was the point I was trying to make. Instead of
"technical considerations", substitute "theoretical considerations". In the
end, they don't matter, it's the sound that matters.

Let's see, there are three autoformer taps and my OPT has three taps so
that's 9 trials plus three without the autoformer. That's a total of 12
unless I eliminate some out of hand (there's those damn theoretical
considerations again).

Gerry


There may well be 3 taps and umpteen windings on your OPT.

It helps the sound if you know the "theoretical considerations" which
underpin the "technical considerations".

They actually do matter rather a lot, and when you have the theory
right, there is a better chance better music follows the better
technical application of theory.

Patrick Turner.
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