Patrick Turner wrote:
snip of Rich's stuff
It is with interest I read your ideas about providing music
with feeling, rather than with false edgy sounding fake bass.
I also see the Fender 400 watt amp you refer to has only 6 x 6550
tubes to make the 400 watts, which means 133 watts per pair of 6550,
which is rather a lot of stress on the tubes, regardless of the brand of tubes used.
First, understand where the 400-PS and GE-6550A came from originally!!!!
Those GE's were made to work in the only test bed of any worth!!!!!!
I had to do testing of the 6550A's that GE had sent to me for testing in the 400's.
It was my feedback to Harry Storm, and Chris McCool on those ENGINEERING SAMPLES, that
tweaked the tube to what it became.
One other little known fact about the GE is the function of the glass used for it, is a
one of a kind with respect to it heat transfer characteristics.
Ever wonder WHY, there is no cooling fan in a 400-PS!!!!!!!
The reason,.... because by the design of the GE-6550A and the make up of the glass, it
doesn't REQUIRE any extra cooling, for that level of performance found in the
400-PS!!!!!!!
When such an amp is is pushed into over drive one would think
that screen currents and grid currents could be rather high,
and the danger of tube damage would be ever present,
especially if someone connects too many speakers accidentally.
That is true of the imports!!!!!!!
And that, is THEIR problem!!!!!!
Ever thought of using a dozen 6550 to do the job?
WHY, with the GE-6550A, runing AB, they can in a modified 400 yield 560 watts R.M.S. @ 50
Hz.
Much higher outputs at higher frequencies, is also normal from the 400's.
Hell, a stock modified will approach 190 watts for each of the three test loads @100 Hz.
The estimated total,... 570 watts R.M.S.
This reduces the power per pair to a more survivable 66 watt.
Audio Research use 16 x 6550 for their Reference 600,
and that 75 watts per pair, same as a humble McIntosh.
Hey, I'm not talking audiophile gear here!!!!!
I want to reproduce the sound of my Jazz Bass, and shake your gut doing it!!!!!
I want to make the bottels dance in the bar, and you can't hear what's doing it.
But you sure as hell can feel what's doing it.
See http://www.turneraudio.com.au/htmlwe...00monobloc.htm
to see a sample.
Nice glass bill when it time to replace 'em all.
But, if you started out with a full set of GE-6550A's, You can most likely figure you
saved your great grand kids a pile of bucks, so they don't need to replace any tubes yet.
Life extention is not measured by just one test case.
Parallel that current tube, with that of the GE, and now see which lives the longest.
So, no matter which way you want to spin the 6550 spin for those from off shore, the GE's
are the ****.
My amps make about 200 watts of class A, and its all very relaxed
and the idea is to have limitless headroom for a hifi situation,
where effortless and distortion free sound is sought.
Yeah, and class A don't beat the **** out of the screens like AB ultra linear does.
There is another example where you don't go sticking the wanna be 6550's straight, in
where the GE's go.
Why, because they ain't the SAME!!!!!
In one of my 8585 hifi amps, I used 8 x jan GE6550, nos, green lettering.
They were about twice the price I pay now for EH6550.
I don't know wherther there was anything really special about them.
After 7 years of on -off use in a hifi situation, they all became prone to
grid current even at idle, and some of the grids going a volt or two positive.
Then I reduced the bias resistors to 100k, and they held their bias better.
Well then, to exactly who's family of 6550 curves was that amp designed.
The GE's, or the wanna be 6550's.
I KNOW, they ain't the same, so which way did the designing go here.
The client had me replace all the tubes with EH 6550,
and he said there was a big improvement in the soundstage,
which seemed to have depth, not only width, as before with GE,
then he said the dynamics and detail were improved.
Like the Tungsol is to the GE, so are other tubes with the same numbers on the glass.
The tube's curves are different, their windows of operation is different, their loading
windows to the OT's are different, and the OT loading designs are different manufacturer
to manufacturer.
So, just where does this all line up for the GE. For the EH.
Get the picture.
With respect to your client:
What is the program material we talking about here.
How long is HIS audio retention good for.
Just what was the length of time between comparisons.
Define his meaning of the words DEPTH and WIDTH.
If that was made with respect to the Sonic Field, that is the biggest crock of **** I've
ever heard!!!!!
Gee, I didn't know that just by changing output tubes, you could IMPACT the hardly heard
anymore 3D sonic field, that truely escapes the clue less engineer/producers of today's
generation
So, this better be a stereo system, and the program material better have that tudio
engineered 3d sonic image, that is very rare in the history of recorded music, for me to
take any of these claims seriously.
Then likewise, Define his meaning of the words DYNAMICS and DETAIL.
Hmmmmmmmm.......................!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!
thinking
Screw it.
What the hell am I supposed to do with this meaningless babble!!!!!!!!!!
What,.. did we get a freq increase or band width increase here!!!
What's the deal.
You tell me!!!
I ain't got no crystal ball.
Where's the RTA, power, and impedance curves of both conditions!!!!!
Hifi amps are never subject to severe signal overloads and gross clipping
with rock musician amps.
OK,.... I guess I just got it!!!!!
Forget what I said one click above.
Your client is all full of crap, and imagined it.
There is NO WAY, a change of output tube can impact the sonic field of STEREO system in
either a well mixed 3D, or the standard BS 2D most ALL of us hear from our everyday
recordings.
Long gone are the days when engineer/producers even had 3D mixing in mind when setting up
the mics in the studio!!!!!!!
So, to me, his words are meaningless!!!!!!!!
As meaningless as the tall tails told by those who've had sex with aliens, and the baby
produced has super hearing for things not of the real world.
But they are left running for hours on end, day after day,
with a substantial bias current to allow lots of class A.
I guess the tubes wear out for different reasons in the
music amp versus the hi-fi amp.
Correct!!!!!
Class A is a waste of electricity, to reproduce silence!!!!!!!!!!!
But then, look of all the tube gear of the past that was left on 24/7 in all the labs
across this land where tolerance and calibration had to be held.
Look at all the communications transmitters that required the same.
There are a lot of 24/7 tube examples besides this one.
So, it's the Class A, that kills ya on this one.
So, as an enviornmentally frendly person, I use AB only for my audio needs.
But, don't you dare call me a Tree Hugger!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
One of the sweetest music amps I heard was 6V6 PP,
about 80% UL taps, nearly triode, in class A.
Another 6V6 in triode drove the output stage via a transformer.
Look, I've had my share of Hifi gear experience through my life time. I also prefer to
follow the laws of mother nature with respect to the natural world around me.
Audiophile books are no substitute for the physics book on the subject, when it comes to
understanding the world around you..
This amp was one of the few which seemed to have sweetness
and a sort of natural reverb,
Here we go again!!!!!!!!!!!!!!!!!!!
Who's on first, what's on second, I don't know, third base!!!!!!!!!!!!!!!!!!!!!!!
Natural room reverb, is NOT the product of ANYTHING, that has anything to do with the
amplifier itself!!!!!!!!
Natural room reverb is governed by other things!!!!!!!!!!!!!!!!!
but without a reverb unit used.
The owner-builder was a physics lecturer, whose interest off campus was guitar,
and rocket engines.
And maybe a collection of tin foil hats in the closet too.
Another client uses Sovtek 6550 in triode in a Marshall head for use
in his "dark metal" band,
OK, now I know about that stuff.
and the sound is basically like a continual stream
of jumbo jets crashing on the pavement in front of you.
There you go again.
Just when I thought we were going to connect, you get weird on me again.
I wouldn't have a clue what the hell the sound of crashing jumbo jets crashing in front of
me would sound like.
Let alone coming from a Marshall in triode with sovtek wanna be 6550's.
****sssssssssssssssssssssssssssst!!!!!!!!!!!!!!!!! !!!
Ummmmmmmmmmmmmmm......................!!!!!!!!!!!! !!!!!!!!
Ya wanna hear what I can do with a 400-PS with three full Marshall stacks on it with my
Strat, fuzz face, vox wah, octave down box, etc.... ALL up on TEN, in full Jimi glory
doing my version of the Star Spangled Banner!!!
You think I would come close to what your friend has going on with the Jumbo Jets
thing!!!!!!!!
Not my cuppa tea, but some folks think its very cool!
The tubes are either off, or 40 dB over clipping.
After 4 years, I think he's on his second pair......
The first pair expired after using too low a load impedance
when swithed to the 16 ohm setting.
So when I hear about tubes failing, I wonder first
about the human element.
No, you have to wonder about the quality of the materials that are actually used in the
tube. The purity of the vacuum of the tube. Then, the degree of vacuum when tipped off.
These are just for starters!!!!!
Unlike Fender, I fit individual cathode current sensors
to each output tube so that if any one tube out of so many
misbehaves, and goes red with too much cathode current,
the amp is turned off.
Good idea!!!!!!!!!!!!!!!
That mightn't suit a muso, who might prefer to blow a few tubes rather than stop
to change to a spare amp between songs, if the fuse hasn't blown.
Patrick Turner
Oh, I see this was cross posted.
That explains things a tad more.
Regards,
Rich Koerner,
Time Electronics.
http://www.timeelect.com
Specialists in Live Sound FOH Engineering,
Music & Studio Production,
Vintage Instruments, and Tube Amplifiers