[Alex Pogossov]

"patrick-turner" wrote in message
news:0bad46cc-e336-417e-ac98-.....

But your statement "Definitely such insulator will give a "wooden" sound --
shallow, flaccid, limp bass." - is utter rubbish because the bass quality of
the reformed Jadis is nothing short of spectacular, and sounds like a good
50W amp.



***
I was only kidding and teasing. Sorry if you took offence.

Probably wood is OK if you do not drive +500V screws near some sensitive
grid circuits screws... But I would not use timber. Teflon is very costly,
of course, so I use polysterene sheets or even pieces of kitchen plastic
cutting boards, but they are not high temperature material. Only low power
circuits can be laid out on them.
***



Real audiophools with determinations always use teflon -- no absorbtion, no
leakage, easily machined, cut, drilled.

Audiophules with determination like to believe they know best by using
teflon that almost nobody else uses because of cost and difficulty in its
use and the inability to use glue to fix it. Audiopules are notoriously
pig-ignorant, knowing almost zero about real world electronic or metal
engineering or about electronic properties of material and how they affect
distortions and noise and sound. What they DO KNOW is mostly a jumble of
bull**** notions not based on any known facts, but based on "what others
have said" on the Net, and on slaes BS and on what Stereophile authors have
poked down their necks. They then profess to be able to tell if any special
capacitor brand has been used or special wore of special any fukken thing.
Fact is, when I have yested their perceptive abilities, they rarely can pick
whether I have used Wima caps or Auricaps, teflon or polyester, or any
difference between either solid state amps I have made, or tube amps. Turns
out the audio enthusiasts who are not complete raving loonies like whatever
I make.

You can dril blind holes and drive screws and pins into them. Will not
carbonise, burn or change properties when overheated during soldering or
when a component is burning.

I understand all that, and would love to used 10mm x 10mm bars of teflon to
make up circuit terminal strips. Its fiendishly expensive stuff. Probably,
like so many modern plastics, its production causes an environmental
nightmare somewhere.
The amps I build rarely ever need to be worked on later because anything to
be done by anyone other than myself would make things worse, because nobody
understands his own product better than me.
So, having wired up the Jadis with a few hardwood plywood boards and
hardwood terminal strips using brass plated steel cupboard hinge screws for
terminals, its more than likely they'll never ever be changed. If someone
were to acquire what I have done and replace terrible horrid wood with
teflon, they'd be telling a whopping lie if they insisted it sounded better.
One could say music should sound organically wondrous, and be supported on
natural substances where possible, including wood, and iron, copper, silicon
because all are natural, ie, found on our planet, without much monstering
and adulteration by industry. Wood Knot Teflon sound clinical, dry, souless,
empty,and unacceptable? Bloody audiopule arguments can be reversed back onto
the stupid *******s. Fact is Jadis SE300W amps were a bloody horror story,
and now at least just TWO samples sound wonderful. The Jadis site says they
are discontinued, and I guess, and I am only guessing, maybe all samples of
that model had OPTs without any air gap, plus the whole pile of other
circuit mistakes and design mistakes which made +1,000 dB more worsening of
sound than any timber board for CCS transistor and protection board, and
test terminals for monitoring Iadc and Iac of each 300B without needing to
move it.

Also I noticed that balancing of the filaments of 300Bs with 33R series
resistors is unnecessary. With the DC filament supply, one end of the
filament is ALWAYS 5V higher or lower, no matter where the self-bias circuit
is connected.

There is few mV of hum across the cathodes. Its negligible. But when I made
amps with 845, guess what, even with cathode Vdc and few mV of hum, a
fraction of a mV got into output so balancing is GOOD PRACTICE even though
you say its BS.

Thus the last 5V of the grid voltage swing is underused, because grid
current from the more negative end of the cathode will prevent full emission
on the more positive end.

In theory, you are correct, in practice, its BS. The difference in emission
along the cathode is utterly negligible and unimportant to operation. Would
you care to quantify your argument? Jadis had used a regulated 5Vdc for 300B
and hum was less than a mV, but they had two balancing 47r resistors.
Trouble weas they used just one 5Vdc supply common to both 300B - big
mistake when tubes are not matched, and running too hot anyway. The very
slight amount of unbypassed resistance in my TWO reformed Rk+Ck circuits =
38 ohms, and the very slight amount of local current FB does SFA good, bad,
or otherwise except stop the two parallel cathode bypass caps ever being
over currented with AC from low Z of 300B cathode. Not likely in fact.

Similraly, this 5V skew smears the tube cut-off -- one end might be cut-off
while the other is conducting.

This is a hi-fi use of class A 300B and they never go anywhere near cut off.
Your argument does not hold water.

Besides the cathode is wearing unevenly, one end always bearing more
emission current, but this should not be a tube life limiting factor.

And it just does not matter!

So this balancing is just a sterotypical thinking.

The balancing was a necessity where AC was routinely used in many amps for
heating. Usually a hum nulling pot was used, and even in PP amps the nulling
is never perfect and in a pair of Sun amps with 2A3 I repaired 10 years ago
the AC heating and pot were retained, and I gave a pair of headphones the
owner could use for nulling. That worked, and noise only seldom appeared at
speakers. My 55W SE55 with 845 had less than 0.25mV of total noise at
output. I know all about how to build amps with low noise, and I'll do it my
way, and not yours.

The four 33R resistors can be safely removed.

Indeed, but they are staying put.

Now, depending on whether the self-bias circuit is connected to a positive
or a negative end of the filament, one would have less or more fixed bias
mixed respectively.

The Reformed Jadis now have individual R&C cathode biasing. Audio Note makes
a similar amp with similar fatures to what I have done. It works, and cannot
easily be ****ed right up by some idiot audio nutter who always manages to
get his testicles in a knot when he tries to adjust the "fixed bias" which
of course is unfixed, and adjustable, and thus able to cause mahem among the
Dopes. My dear customer here has an excellnt range of human abilities, and a
fine man he is, but he just has no clue how to use a voltmeter, like 99% of
the rest of the population. Leak and Quad used cathode biasing for obvious
reasons although I'd say again Quad were idiots to have one lone 180r to
bias both KT66.
But maybe Peter Walker owned shares in the MOV tube making Co, so the more
KT66 people bought because of bias failure with his crummy biasing meant he
got richer. Plus, omitting one R and one C allowed him to buy a Morris Major
in 1960instead of a Morris Minor, wow, wonders wood never cease.

BTW, about 10 years ago I totally re-engineered a large stereo VAC amp with
4 x 300B per channel. Jadis ain't alone and producing rubbish that smokes.
Anyway, in went timber circuit strips, worked well, very rugged, but the
grid cicuits did use teflon insulated wires point to point with no grid
potential points to any wood board/strip. Caps were boxed polypropylene
Wimas siliconed to chassis so that the grid wiring could be slung from short
cap leads acting as terminals.
Certainly no lossy PCB boards were used, with stuff all jammed tight, and
boards blocking natural air convection flows. Don't worry Alex, I know what
I am doing.

I have done many amps over the last 18 years and not one has had to be
returned as a result of my poor tradesmanship. I'm now retired, and may not
make too many more amps.

Patrick Turner.