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On Sat, 25 Feb 2017 12:12:56 -0500, Michael Black <et472@ncf.ca> wrote:
This is a good article about the "Wall of Sound".
It was (and probably still is) the greatest sound system ever built, but
it nearly bankrupt the Dead, and moving all that equipmnt from show to
show does seem very impractical. Those mcintosh MC3500 amps are still
the best anps ever built. More powerful solid state amps have been
built, but none can match that tube sound.
https://motherboard.vice.com/en_us/article/the-wall-of-sound
I dont doubt that there were fried amps, blown speakers and so on at
those concerts. Everything was being run at Max power and much of this
was still in development stages.
Paralleled tubes like you said, dont seem real practical for audio amps.
Having that high DC voltage on the speaker leads seems very dangerous.
On Sat, 25 Feb 2017, oldschool@tubes.com wrote:
On Fri, 24 Feb 2017 16:11:20 -0600, Jon Elson <jmelson@wustl.edu> wrote:
oldschool@tubes.com wrote:
No, certainly not! You use the modulator from an old AM broadcast
transmitter. I was at a Grateful Dead concert in 1969 and they wheeled out
this THING on the stage with big glass globes, and when they lit up I
realized they were TUBES (valves to the British)! Not sure of the type, but
at least several thousand Watts. I borrowed a set of ear muffs and sat back
for a show!
Jon
I was at several Grateful Dead concerts in the late 60's and afterwards.
I never saw any such thing. Are you sure you were not "tripping"? That
may have just been a common 6L6 tube in a guitar amp, and your
hallucinations made it look really BIG....
They went through various iterations, and sound people. SOmeone got
hooked in at one point, maybe it was Bob Heil but maybe it was the
soundman for Quicksilver Messenger Service (who was also a ham), there was
s story of someone having an Electrovoice "Voice of the Theatre" or
whatever it was adapting that. Owsley was involved, leading to the Wall
of SOund, which almost as soon as they finally got it going right, they
abandoned. They were using McIntosh amplifiers for a while, there's a
story, maybe about Woodstock, where they blew them out and had to hurry to
find replacements, finding a "close" dealership and getting them to open
up on a Sunday or something.
Things were evolving, and bands like the Dead helped that developemnt. So
they went to that Wall of SOund to adapt to the much bigger venues, then
dropped it because it was too much trouble to move, but I thought the work
helped other things to develop. So they may have been using just about
anything at some point, including home built equipment.
If you paralleled enough tubes, the output impedance would go down, so no
matching transformer for 8ohm speakers. I'm not sure if that was ever
done with audio, but I have seen it done with radio amplifiers, a bunch of
tubes in parallel so the output impedance is 50 ohms to match the coax.
Michael
This is a good article about the "Wall of Sound".
It was (and probably still is) the greatest sound system ever built, but
it nearly bankrupt the Dead, and moving all that equipmnt from show to
show does seem very impractical. Those mcintosh MC3500 amps are still
the best anps ever built. More powerful solid state amps have been
built, but none can match that tube sound.
https://motherboard.vice.com/en_us/article/the-wall-of-sound
I dont doubt that there were fried amps, blown speakers and so on at
those concerts. Everything was being run at Max power and much of this
was still in development stages.
Paralleled tubes like you said, dont seem real practical for audio amps.
Having that high DC voltage on the speaker leads seems very dangerous.