[tubegarden]

Hi RATs!

OK, I only build tube audio circuits for fun. Getting the tubes to
light up is the quickest way for me to enjoy seeing a new circuit in
all its thermionic glory.

Lit up tubes seem much more enthusiastic, at least to me.

Besides, designers who do not provide a dedicated power transformer
and filter circuits for filaments are just cheap.

Cheap is over rated.

There may or may not be sonic reasons to seperate power supplies, but,
I suggest cheap is not the best one ...

People hire engineers and mention, somewhat forcefully, that economy
is important.

I am an old guy in bed. I have more transformers and other parts than
I can even remember. I am not motivated to be cheap, any more.

I have seen some of the best minds of my generation set to the task of
fitting more code into the filled up space of a cramped hardware
implementation. It was mildly challenging. It was a total waste of
time. That hardware was no longer marketable long before the specs
were even updated.

Henry Ford wanted to build black model T's forever. We may well be
lucky he wasn't God.

Anyway, I run one pair of wires from the filament power supply to each
tube. Yes, you can save some wire if you do it some other way. It will
not sound better.

I am finished and enjoying the beauty of the lit tubes while you are
still trying to save the world from mankind, one inch of wire at a
time. Whatever floats your boat.

I like to see my tubes lit up. It motivates me to get them singing.

Happy Ears!
Al

[maxhifi]

"tubegarden" wrote in message
ups.com...
Hi RATs!

OK, I only build tube audio circuits for fun. Getting the tubes to
light up is the quickest way for me to enjoy seeing a new circuit in
all its thermionic glory.

Lit up tubes seem much more enthusiastic, at least to me.

Besides, designers who do not provide a dedicated power transformer
and filter circuits for filaments are just cheap.

Cheap is over rated.

There may or may not be sonic reasons to seperate power supplies, but,
I suggest cheap is not the best one ...

People hire engineers and mention, somewhat forcefully, that economy
is important.

I am an old guy in bed. I have more transformers and other parts than
I can even remember. I am not motivated to be cheap, any more.

I have seen some of the best minds of my generation set to the task of
fitting more code into the filled up space of a cramped hardware
implementation. It was mildly challenging. It was a total waste of
time. That hardware was no longer marketable long before the specs
were even updated.

Henry Ford wanted to build black model T's forever. We may well be
lucky he wasn't God.

Anyway, I run one pair of wires from the filament power supply to each
tube. Yes, you can save some wire if you do it some other way. It will
not sound better.

I am finished and enjoying the beauty of the lit tubes while you are
still trying to save the world from mankind, one inch of wire at a
time. Whatever floats your boat.

I like to see my tubes lit up. It motivates me to get them singing.

Happy Ears!
Al


Hi Al,

It sounds like you have a lot of fun with each project! For me the reward
comes from hearing music, not from seeing the tubes lit up - and here is
why. The first big amplifier I ever built, when I was 16, after several
years of 6V6's and 50L6's and IC amps, I 'designed' to look like an HK
Citation II. I spent all my extra money on transformers, and I thought I hit
a major milestone when the tubes lit up, as though it would only be a bit of
quick soldering, and my Goodmans would be heard all over the neighborhod!

I admired its beauty for a few days, before going on to finish it. It turned
out that my design, for a variety of reasons, including layout, circuit
design, and power supply design, was so flawed, that it was never to play
music! The best I could do was get it to oscillate, and arc over at the pins
of the 6550s!

I humbly withdrew to my books, re-built the entire thing on a new chassis,
and copied a circuit from the GEC book to end up with a decent sounding
amplifier. Several years later I rebuilt it again with my own design, using
the same transformers, and was rewarded with an excellent sounding
amplifier.

I have learned a lot since then, but I still refuse to take any pleasure in
just seeing filaments lit up, as it reminds me of my first, non-starting
project!

As for DIY, I am not too excited about paying money for power transformers,
when it's so easily possible to scrounge one out of the 'ether' which will
do the job well! I'll use the filament windings if they're present, or a
separate transformer if they are not! Wiring the filaments first, is of
course the best idea, because it means you have a nice empty path for the
wires, and you don't have to weave them in and out of components and
terminal strips. It also allows you to have a nice neat layout, using
tightly twisted pairs (a drill comes in handy for the twisting duty).

[tubegarden]

Hi RATs!

I have a stand alone Power Supply that I modify the filter of, for the
circuit of the moment. I build circuits one at a time and everything
goes back into my inventory.

I have several big old Lambda power supplies which provide various odd
filament voltages.

And lots of filament transformers have accumulated

The only tubes I used chokes in the filament supply were the SV572-3.

For fixed up old amps, I often add a choke to their B+ supply.

I have lots of power supplies, but, no bench

Steve Bench is one of my heroes, does he count?

Happy Ears!
Al

[Engineer[_2_]]

On Aug 19, 6:13 pm, tubegarden wrote:
Hi RATs!

I have a stand alone Power Supply that I modify the filter of, for the
circuit of the moment. I build circuits one at a time and everything
goes back into my inventory.

I have several big old Lambda power supplies which provide various odd
filament voltages.

And lots of filament transformers have accumulated

The only tubes I used chokes in the filament supply were the SV572-3.

For fixed up old amps, I often add a choke to their B+ supply.

I have lots of power supplies, but, no bench

Steve Bench is one of my heroes, does he count?

Happy Ears!
Al

I often power vintage test or repaired P-P amplifiers (also AC radios)
from a bench supply - sometimes from a Heathkit regulated tube P/S and
sometimes from a solid state unit run off a variac. I use an octal
tube base with pin 8 connected to the external B+, plugged into the
rectifier socket, and the negative tied to ground (don't let the
ground wire go open circuit!)

About the OP...
On new projects, as most do, I wire the heaters first with tightly
twisted pair pushed down close to the chassis (but I don't spend time
watching the tubes glow until I have finished - then I do!) I
recently had to fix a badly built amplifier in which one side at the
the end of the heater string had shorted to chassis (the 6.3 VAC CT
was grounded.) Plastic insulation had melted back to the point where
the 6.3 VAC transformer wires were connected (latter not damaged,
fortunately.) It was the devil's own job desoldering and fishing out
the old heater wiring from underneath everything else... one tube
ended up being wired with a "6.3 VAC overpass"! BTW, no hum, not a
preamp.

Cheers,
Roger

[West]

"tubegarden" wrote in message
ups.com...
Hi RATs!

OK, I only build tube audio circuits for fun. Getting the tubes to
light up is the quickest way for me to enjoy seeing a new circuit in
all its thermionic glory.

Lit up tubes seem much more enthusiastic, at least to me.

Besides, designers who do not provide a dedicated power transformer
and filter circuits for filaments are just cheap.

Cheap is over rated.

There may or may not be sonic reasons to seperate power supplies, but,
I suggest cheap is not the best one ...

People hire engineers and mention, somewhat forcefully, that economy
is important.

I am an old guy in bed. I have more transformers and other parts than
I can even remember. I am not motivated to be cheap, any more.

I have seen some of the best minds of my generation set to the task of
fitting more code into the filled up space of a cramped hardware
implementation. It was mildly challenging. It was a total waste of
time. That hardware was no longer marketable long before the specs
were even updated.

Henry Ford wanted to build black model T's forever. We may well be
lucky he wasn't God.

Anyway, I run one pair of wires from the filament power supply to each
tube. Yes, you can save some wire if you do it some other way. It will
not sound better.

Then why do you do it? Running separate filament wires may not be the best
way aesthetically or the best way for hum management. Is there any advantage
to running separate wire pairs?

west
snip

Happy Ears!
Al

[Peter Wieck]

On Aug 22, 4:42 am, "West" wrote:

Then why do you do it? Running separate filament wires may not be the best
way aesthetically or the best way for hum management. Is there any advantage
to running separate wire pairs?

Uh.... he stated clearly why he does it. Because it is his choice. No
more need be written as far as he is concerned.

As to practical reasons, it is true that separate pairs might deliver
(very, very slightly) more stable voltage than a long parallal
"ladder" supply, and will offer more routing choices (balanced by more
wire). But the bottom line is that Al chooses this option as well as
filtered DC for filament power. Others may choose differently. Not all
ice cream is butter-pecan.

Peter Wieck
Wyncote, PA

[Ian Iveson]

Then why do you do it? Running separate filament wires may not be
the best
way aesthetically or the best way for hum management. Is there any
advantage
to running separate wire pairs?

Aesthetically pleasing? There's not much you can do with a single run
of wire. With many, there is scope for expression. Perhaps with many
coloured wires in traditional twisted pairs you could contrive an
impressionist scene. Little fishes and a dolphin or two; maybe a
shipwreck and a gamboling seal, and a shark to add menace. Later, you
can build, above, a harbour with piers, tied-up boats, and a
lighthouse. All under the chassis: your secret little world of art.

There is no point in building an amplifier like one you can buy,
unless you want to sell it. Tell me one thing that is good, from the
point of view of an amateur, about a bus. Even for heaters connected
in series, where it is not a liability, a bus is commitment that you
are bound to regret.

The heater wires go in first so they can be tucked up to the chassis
where they belong. Consequently, later on, they are the hardest to
change.

With separate supplies, you can elevate, or depress, each heater's
potential, as the fancy takes you.

Just thought of Choky, who used to be our Elevation Consultant. Wonder
if that lot are still chatting somewhere amongst themselves.

As for "hum management", the same argument applies. What, please, is
better about a bus?

cheers, Ian