Home » Audio » Thermionic Emissions » New Production Tung Sol 6550, Penta KT88s (Concerning Audio Quality)
New Production Tung Sol 6550, Penta KT88s [message #96284] Wed, 18 January 2023 23:01 Go to next message
positron is currently offline  positron
Messages: 63
Registered: May 2020
Viscount
My first question is, what do you think of the general sonic quality
of these two tubes. Does each have a sonic reputation?
Try to be as specific as possible with any response.

Thanks and cheers

pos
Re: New Production Tung Sol 6550, Penta KT88s [message #96292 is a reply to message #96284] Sat, 21 January 2023 18:24 Go to previous messageGo to next message
positron is currently offline  positron
Messages: 63
Registered: May 2020
Viscount
Evidently no one uses them?

My testing has found both tubes to be rather thin, anemic sounding compared to JJs and Winged Cs.

So I demagetized both, using my 100 watt soldering gun magnetic field (gun windings), and both tubes became fuller than the JJs and Winged Cs. Quite a sonic change. The new Pentas just slightly fuller than the new Tung Sols.

When the tubes are manufactured, induction heating of the plate removes gases. Evidently, the switch/field is simply flipped, rather than gradual field removal.

So when one purchases a new output tube, what you purchase and hear is not necessarily what the tube sounds like after being demagnetized.

One could probably use a dryer, a motor, anything that produces an AC magnetic field. Simply rotate each tube around the AC device field, and then gradually distance the tube from close to 3 feet or more from the device, and power off the device.

cheers

pos
Re: New Production Tung Sol 6550, Penta KT88s [message #96295 is a reply to message #96292] Sat, 21 January 2023 20:48 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18428
Registered: January 2001
Illuminati (33rd Degree)

Who'da thunk it?

Degaussing a tube! Interesting observation!
Re: New Production Tung Sol 6550, Penta KT88s [message #96296 is a reply to message #96295] Sat, 21 January 2023 21:33 Go to previous messageGo to next message
positron is currently offline  positron
Messages: 63
Registered: May 2020
Viscount
Neither tube initially sounded very good at all in my system Wayne.
But I have performed this trick before, so I degaussed both and the
sound sure improved. The zingy highs, the thin sound are no longer.

Best guess of the top of my head is it creates random molecular orientations.? I would have to delve more deeply with a
physics/chemistry expert.

Caveat: My system was a lab system (now in my apartment) is
extremely sensitive. The sound is also not sterile, but very natural.

There are multiple tweaks that I can perform to cross check and
see if the sensitivity results match.

One is being able to alter a crossover resistor by 1/1,000,000 of an
ohm with timber, sound stage change etc heard.

Another is, for each speaker leg, I use ten 18 gauge wires in parallel, 6 feet long. If I change to 9 or 11 wires in one leg, the timber, sound stage changes etc.

Audiophile Dan comes over (50 mi) so we have opportunities to make changes
and decide if a tweak is an improvement or detriment.

Cheers

pos







Re: New Production Tung Sol 6550, Penta KT88s [message #96297 is a reply to message #96296] Sun, 22 January 2023 17:28 Go to previous messageGo to next message
positron is currently offline  positron
Messages: 63
Registered: May 2020
Viscount
Another tidbit is the frequency response change of 1/1,000,000 equates to
-114 to -120db down from the fundamental (one to one on the steepest part of the signal slope).

Even though small, the change covers octaves of bandwidth. Rane Corp found a change covering 1/3rd octave or less is generally not perceived.

A spec of +/- 0,1db equates a change of only about -54db. Not surprising to me that we notice sonic differences of different manufacturer's components even though the frequency response are the same, +/- 0,1db 20 to 20khz.

Cheers

pos
Re: New Production Tung Sol 6550, Penta KT88s [message #96301 is a reply to message #96297] Mon, 23 January 2023 20:25 Go to previous messageGo to next message
gofar99 is currently offline  gofar99
Messages: 1778
Registered: May 2010
Location: Southern Arizona
Illuminati (4th Degree)
Hi, something I would not have guessed. I agree that really small changes in components can make a difference. 0.1db of the wrong stuff in the wrong place can really mess up a good design. The saving grace if you want to call it that is the speaker and if you use a turntable the cartridge errors are far worse and will mask a lot of ones internal to the electronics.

Good Listening
Bruce
Re: Demagnetizing Tung Sol 6550, Penta KT88s [message #96302 is a reply to message #96301] Mon, 23 January 2023 22:12 Go to previous message
positron is currently offline  positron
Messages: 63
Registered: May 2020
Viscount
gofar99 wrote on Mon, 23 January 2023 20:25
Hi, something I would not have guessed. I agree that really small changes in components can make a difference. 0.1db of the wrong stuff in the wrong place can really mess up a good design. The saving grace if you want to call it that is the speaker and if you use a turntable the cartridge errors are far worse and will mask a lot of ones internal to the electronics.
Hi Bruce,

Over the years, the sensitivity of the ear has certainly surprised me
as well.

What is just as surprising to me is that the electronic designs/parts
heavily influence as well. Consider that I am using a two way speaker
to perceive sonic differences to astonishing low levels.

This is a long lab experiment for me,

1. to find out just how sensitive one's ear is,
2. that some electronics designs (and parts available) are better than
others. Finding the best design, and parts.
3. what is possible, just how accurate to the source can the
electronics be under the best conditions.

Just trying to help out in the electronics as Wayne
is doing with his excellent speaker designs.

Back to the topic at hand. I believe the new production Tung Sols and Pentas
can be used to good effect if the plates are demagnetized. Otherwise, I did not like either.

Cheers

pos
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