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RE: OK, Pak ...

Hi! Jeff likes the 6005 tube as I do.

A 6005 amp isn't practical to sell to
anyone, a good one costs as much to build
as any other SE, but can't power most things.

Jeff is different-- he just wants to build
things that I highlight in our discussions.

It's been about 4 years since I got him
converted to Altec A7-- 500, or 800 8's.

This old movie theatre speaker is a rare
combo of great transducers, and a bass bin
that isn't bass reflex, nor is it MLTL, or
anything else. It's for a movie theatre.

Clarity is everything in a movie house.
Bass response, while accentuated by today's
"engineers", is really a cult throwback to
the car-audio of a few years ago, and the sick
druggies who drive them. In that world, bass
response is designed to induce bowel movements, and
nothing else of value.

Movie theatres had to have a system where the
viewer got caught up in the action and forgot all
about audio and video. The speaker(s) was designed
to do just that, so a combo of PART bass reflex and PART
free-air woofer-loading was devised by Jim Lansing
for MGM-- MGM hated Western Electric gear with a
vengeance. Jim was hired to get the W.E. JUNK out of
all of their movie theatres. ALTEC was born.

Jeff, reluctantly, finally got into Altec speakers
after almost 12 years of me trying to get him to do it.
He was hung-up on Robert Fulton.

Of course, you hear clean, clear detail with Altec
speakers. I began designing amps for Jeff, and he
took those ideas to the forums.

The 6005 tube, while excellent, is no match for larger
tubes such as the 2A3, but due to closer element-spacing,
it is a thrill to listen to-- it easily does everything
in music.
I have to beat Jeff over the head all the time to get him
to use vacuum tubes which DO NOT have soldered-on pins,
all of which are anti-clean, with only "so-so" detailed
response.

The 6005
is, of course, one of the GOOD tubes-- with direct pins
for the tube socket.

I know how to build a (3) tube 6005 output stage, and
still keep it clean and coherent. This requires a
balancing act to keep all 3 tubes acting in the same
manner, when we know that no 2 tubes are ever alike--
not in any way, and not by any manufacturer.

This means skewed output phases unless you know how
to do it. I talked Jeff into building one, and designed
it over the phone. As usual, Jeff went right to the forums
with it-- before it is even built. He thinks that if do it,
it has to work.

Anyhow, it is designed to man-handle the A7-500-8 woofer.
All woofers like current-- the faster it is delivered, the
better. It took me a week to get anybody to understand
that a 3-banger output stage can be made to work sonically.

The improvement in the Altec 15" woofer's response will be
huge from the 3 tubes, partly because the output transformer
can be lower impedance primary. The larger the wire size, and
the fewer turns we have, the better. Oh, I know TRE would
be enraged by this-- he knows that THD drops as primary
impedance goes up. He's right, but I don't give a damn--
what I want is fast, clean response. Numbers are just mental
exercise-- I use them, but only when they aren't allowed to
interfere with what I want-- accurate musical expression.

So, the Triple 6005 amp is born--
just like MGM, you gotta use and drive properly the right
speaker.

-Dennis-



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