[Andre Jute[_2_]]

Patrick Turner, and outspoken Australian, wrote:
Being of sound mind
because I do try to keep an open mind I would hazard a guess that not
all of what "ultrafidelista" might hold as the truth and nothing but the
truth is in fact not the truth at all and might be just a series of
maybe maybe statements.

Yo, Patrick, you're making the same mistake I made when I first ran
into the ultrafidelista: quoting science at them. You'd do better to
quote the Bible at them; have a greater effect, very likely. The hard
core ultrafidelista knows what he believes in and you're wasting your
breath explaining the truth to him.

However, by constant practice at listening hard, and spending lots of
money to extract a few gems of truth from the dross of street myths
and shakti stones, the ultrafidelista have done us all a favour. I got
to be a high priest of the ultrafidelista because by collecting the
bits of their wisdom that had a genuine electronic basis, or simple
superiority on my trained and cultured ear, I found it easy to build
amps that not only sounded better but were electronically superior of
their type.

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

The same applies in loudspeakers: without the ultrafidelista, the horn
loudspeaker, to cite only one instance, would now be dead.

Much as we might enjoy kicking around the loony cableswapping
wannabes, at the serious DIY end of the ultrafidelista to which I
belong there has always been a good deal of serious engineering going
on, conducted by concert-goers of excellent taste. Someone has to
stand up for them.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[John Byrns]

In article ,
Andre Jute wrote:

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

I disagree with you that bootstrap topologies belong in this group. Bootstrap
topologies were and are the darling of commercial makers because they permit the
construction of amplifiers with a lower cost.

--
Regards,

John Byrns

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

[Andre Jute[_2_]]

On Nov 30, 4:17*pm, John Byrns wrote:
In article ,
*Andre Jute wrote:

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

I disagree with you that bootstrap topologies belong in this group. *Bootstrap
topologies were and are the darling of commercial makers because they permit the
construction of amplifiers with a lower cost.

Eh? When I mentioned bootstrap technologies, I had in mind the SRPP,
which Japanese ultrafidelista kept alive all those years, a circuit
for half a century so obscure that it isn't even in the RDH and is
called something else in Vacuum Tube Amplifiers. How can a two-tube
stage be more economical than a single tube?

--
Regards,

John Byrns

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

I don't get it. Won't be the first time...

Andre Jute
Always glad to learn something new

[BretLudwig]

The "ultrafidelistas" are not fidelistas at all but "soundmodificantes".
Their goofy piles of industrial junk MODIFY the signal for a result THEY
LIKE BETTER, but which is LESS FIDELIOUS to the original signal. AND THEY
KNOW IT, but DON"T CARE, and will DENY it to outsiders until cornered.

--
Message posted using http://www.talkaboutaudio.com/group/rec.audio.tubes/
More information at http://www.talkaboutaudio.com/faq.html

[John Byrns]

In article ,
Andre Jute wrote:

On Nov 30, 4:17*pm, John Byrns wrote:
In article
,
*Andre Jute wrote:

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

I disagree with you that bootstrap topologies belong in this group.
*Bootstrap
topologies were and are the darling of commercial makers because they
permit the
construction of amplifiers with a lower cost.

Eh? When I mentioned bootstrap technologies, I had in mind the SRPP,
which Japanese ultrafidelista kept alive all those years, a circuit
for half a century so obscure that it isn't even in the RDH and is
called something else in Vacuum Tube Amplifiers. How can a two-tube
stage be more economical than a single tube?

First I don't remember saying anything about numbers of tubes, just lower cost.

Bootstrap topologies were/are often used in both tube and solid state circuits
to increase the voltage output capability of an amplifier stage without
resorting to the extra expense of an additional higher voltage B+ supply for the
stage in question. For an example of bootstrapping in a tube amplifier, check
out the push-pull voltage amplifier stage, the stage following the phase
inverter, in the classic McIntosh Mc30 amplifier. Your homework assignment is
to study the voltage amplifier stage of this amplifier, understand how it works,
and then explain it to the class so that those less gifted than you may also
come to understand bootstrapping.

--
Regards,

John Byrns

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

[Andre Jute[_2_]]

On Dec 1, 1:29*am, John Byrns wrote:
In article ,
*Andre Jute wrote:

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

I disagree with you that bootstrap topologies belong in this group.
*Bootstrap
topologies were and are the darling of commercial makers because they
permit the
construction of amplifiers with a lower cost.

Eh? When I mentioned bootstrap technologies, I had in mind the SRPP,
which Japanese ultrafidelista kept alive all those years, a circuit
for half a century so obscure that it isn't even in the RDH and is
called something else in Vacuum Tube Amplifiers. How can a two-tube
stage be more economical than a single tube?

First I don't remember saying anything about numbers of tubes, just lower cost.

I don't know the relative costs back in the day of tubes,
transformers, caps, resistors and pots, but I don't find it difficult
at all to imagine some obsessed engineer sitting at his drawing board
when he should be playing with his children, trying to eliminate all
the caps in an entire amp. (The exemplary Steve Bench actually
published such a schematic a few years ago, just for a laugh.)

Bootstrap topologies were/are often used in both tube and solid state circuits
to increase the voltage output capability of an amplifier stage without
resorting to the extra expense of an additional higher voltage B+ supply for the
stage in question. *

Aha! That is not a reason recognized by the ultrafidelista who
generally believe that "mo' iron is betta iron" and even have a
bragging measure to account for the amount of iron in an amp, called
the Dunker Factor, which measures kilograms per watt of output, the
higher the better.

For an example of bootstrapping in a tube amplifier, check
out the push-pull voltage amplifier stage, the stage following the phase
inverter, in the classic McIntosh Mc30 amplifier. *Your homework assignment is
to study the voltage amplifier stage of this amplifier, understand how it works,
and then explain it to the class so that those less gifted than you may also
come to understand bootstrapping.

Okay, you caught, me out, I was applying tunnel vision. If I'd known
this was going to be a thesis standard interrogation...

The CFB via the extra winding, intended to decrease distortion, also
results in a very high drive requirement. The answer is found in
positive feedback on an earlier stage.

Crowhurst showed an analysis somewhere but I don't have time to search
for it now.

Regards,

John Byrns

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

Another question this schemo throws up, if I have it right: Is the
output stage operated on such low idle currents that we're looking at
something near Class B output?

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Andre Jute[_2_]]

On Dec 1, 4:42*am, flipper wrote:
On Sun, 30 Nov 2008 19:29:19 -0600, John Byrns
wrote:



In article ,
Andre Jute wrote:

On Nov 30, 4:17*pm, John Byrns wrote:
In article
,
*Andre Jute wrote:

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

I disagree with you that bootstrap topologies belong in this group.
*Bootstrap
topologies were and are the darling of commercial makers because they
permit the
construction of amplifiers with a lower cost.

Eh? When I mentioned bootstrap technologies, I had in mind the SRPP,
which Japanese ultrafidelista kept alive all those years, a circuit
for half a century so obscure that it isn't even in the RDH and is
called something else in Vacuum Tube Amplifiers. How can a two-tube
stage be more economical than a single tube?

First I don't remember saying anything about numbers of tubes, just lower cost.

Bootstrap topologies were/are often used in both tube and solid state circuits
to increase the voltage output capability of an amplifier stage without
resorting to the extra expense of an additional higher voltage B+ supply for the
stage in question. *For an example of bootstrapping in a tube amplifier, check
out the push-pull voltage amplifier stage, the stage following the phase
inverter, in the classic McIntosh Mc30 amplifier. *Your homework assignment is
to study the voltage amplifier stage of this amplifier, understand how it works,
and then explain it to the class so that those less gifted than you may also
come to understand bootstrapping.

Another form of bootstrap is to increase impedance.

You know, reducing complexity and cost isn't necessarily a 'bad thing'
and can be the result of creativity vs brute force.

True. It is just sometimes a bit difficult to explain to the
ultrafidelista that in audio electronics creativity too must answer to
the laws of physics. And those among them who consider taste a license
for "personal EQ" simply betray the legacy of Messrs Gilbert and
Walker, and their American equivalents.

Brute force in SE amps is an expensive waste. You spend 1000% more and
get 1% better sound: the economic law of marginality run riot. The
300B is so popular because it is a good compromise between the 2A3
class, which requires huge speakers, and the kilovolt class like the
superb 845 which is expensive and hot and dangerous.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Patrick Turner]

Andre Jute wrote:

On Dec 1, 1:29 am, John Byrns wrote:
In article ,
Andre Jute wrote:

Among the gifts of the ultrafidelista are the reliance on triodes, on
single-ended operation, on Class A1 operation, the clever use of power
tubes as drivers, the survival of bootstrap topologies, choke loads on
everything, the reintroduction of CCS to audio circuits, and much,
much more that the commercial makers would never have brought back, or
permitted, without the small but fierce market the DIY ultrafidelista
created.

I disagree with you that bootstrap topologies belong in this group.
Bootstrap
topologies were and are the darling of commercial makers because they
permit the
construction of amplifiers with a lower cost.

Eh? When I mentioned bootstrap technologies, I had in mind the SRPP,
which Japanese ultrafidelista kept alive all those years, a circuit
for half a century so obscure that it isn't even in the RDH and is
called something else in Vacuum Tube Amplifiers. How can a two-tube
stage be more economical than a single tube?

First I don't remember saying anything about numbers of tubes, just lower cost.

I don't know the relative costs back in the day of tubes,
transformers, caps, resistors and pots, but I don't find it difficult
at all to imagine some obsessed engineer sitting at his drawing board
when he should be playing with his children, trying to eliminate all
the caps in an entire amp. (The exemplary Steve Bench actually
published such a schematic a few years ago, just for a laugh.)

Bootstrap topologies were/are often used in both tube and solid state circuits
to increase the voltage output capability of an amplifier stage without
resorting to the extra expense of an additional higher voltage B+ supply for the
stage in question.

Aha! That is not a reason recognized by the ultrafidelista who
generally believe that "mo' iron is betta iron" and even have a
bragging measure to account for the amount of iron in an amp, called
the Dunker Factor, which measures kilograms per watt of output, the
higher the better.

"Mo'iron" can make for better hi-fi but only if you know what your'e
doing.

But the pounds per watt for the best hi-fi is spoken about in the RDH4
pages about OPT construction.
Hardly anyone took the RDH4 message seriously.

Many amp making companies have for years tried to foist upon the public
a bunch of miserable examples of bean counting in the form of
lightweight under-performing transformers in all sorts of gear.

There is somewhat more to transformers than just the weight.

For an example of bootstrapping in a tube amplifier, check
out the push-pull voltage amplifier stage, the stage following the phase
inverter, in the classic McIntosh Mc30 amplifier. Your homework assignment is
to study the voltage amplifier stage of this amplifier, understand how it works,
and then explain it to the class so that those less gifted than you may also
come to understand bootstrapping.

Okay, you caught, me out, I was applying tunnel vision. If I'd known
this was going to be a thesis standard interrogation...

Bootstrapping sort of works in McI amps. But only because the triodes in
the final gain stage LTP have low Ra and this prevents the positive
feedback fed back via the bootstrap anode load resistors to have much
effect.

I've built SE amps needing over 100Vrms drive to output tube grids and
its child's play to get less than 1.5% 2H from a pair of EL84 in triode
fed dc from a 60H choke plus 10k resistor, and cap coupled to the output
stage with normal 1uF and 50k biasing R.
McI could have used a scheme like my balanced LTP with ungapped choke
and R dc loads and two EL84, but of course they wouldn't, because their
way was/is cheaper.

In my 300W amps I now use 20% CFB in the output stage via a sample of
the Acoustical circuit. I need about 150Vrms grid to grid to drive the
amp to clipping. Driver stage THD is extremely low and much lower than
output stage distortion so hardly any global NFB is needed. Just enough
to lower the Rout of the amp a bit more than when GNFB isn't used. No
bootsrapping is used anywhere. I could use it easily, but I have not.
I'm not sure if a huge sonic degradation would occur if I did utlilise
bootstrapping, or even mild PFB, rather than build the driver stage so
it does not need bootstrapping because its so darn linear and had heaps
of voltage headroom.

In preamps, I do like the boostrapped follower known now as the
µ-follower.

Measures well and sounds great.

Patrick Turner.





The CFB via the extra winding, intended to decrease distortion, also
results in a very high drive requirement. The answer is found in
positive feedback on an earlier stage.

Crowhurst showed an analysis somewhere but I don't have time to search
for it now.

Regards,

John Byrns

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

Another question this schemo throws up, if I have it right: Is the
output stage operated on such low idle currents that we're looking at
something near Class B output?

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review