Rich Beato YouTube Channel

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In the room with Reitzas

 

The Pleiades single electron tube EF183 power amplifier in class A (electrons flowing all the time) sounds amazing

 At your risk. Potential lethal voltage. Take all safety precautions.

Operation conditions: Va=120V, Ia=20mA, 1:12 input transformer, 5KOhms to 4Ohms output transformer, Celestion Ditton 150 speaker used is 8Ohms.

Signal path:

Constant Craving - K. D. Lang on CD - Sony CD Walkman line out - Pleiades EF183 single ended power amplifier - Celestion Ditton 150 

Huge bass, smooth mid and treble, dynamic.

It is funny how loud and big just.an electron tube the size of ECC83 can sound.

Limit to how powerful a single transistor power amplifier can be?

 At your risk.

Signal path:

Constant craving - K. D. Lang on CD - Sony CD Walkman line out or Philips CDR 870 line out - Pleiades 2N3055 power amplifier  with various output transformer ratios, Vb= 9V or 12V or 24V - Marantz Imperial 5C

Trying to increase power output by increasing Collector power dissipation (by changing Vb or base bias current), increased loudness but not as much as expected while transistor with a heatsink was getting warm.

It seems there is a limit as transistor amplifiers need signal power input due to their low input impedance which depend on how much the collector circuit is loaded. There is hfe (ratio of collector current to base current), and if the collector current is increased the base current must be increased to and the same applies to a changing base collector or base current i.e. a signal current. 

A CD player at line out for example can give a certain amount of small power output.

Connecting the sigle electron tube Pleiades EF183 power amplifier at 2.4W plate dissipation to the CD Walkman line out gave by comparison a huge sound, surprisingly loud and big. The reason seems to be that an electron tube does not take power from the signal source as it has a very high input impedance.

So it seems the winner will be the electron tube.

A Darlington can be tried. But it is 2 transistors although the configuration or connection between them is a simple as possible.

   . 

Can output transformers be made with ordinary power transformer laminations?

 At your risk. Take all safety precautions. Potentially lethal voltages may be present. 

Surprisingly enough the sound can be very good. See previous post.

Yesterday by the way on the larger transformer the I laminations were separated from the E laminations while music was playing. Bass reproduction decreased as expected. Then E laminations were removed, mid reproduction was decreased as expected by high frequency reproduction was still there. Meaning that the high frequencies can pass through air without needing the metal.

In fact this seems to be more correct. The primary is now a coil without core. Its inductance is low. But since reactance is ohms is proportional to frequency too, impedance is high at high frequencies. So the output impedance of the transistor is not loaded so there is no voltage drop. Therefore high frequencies appear at the primary and since the coils are hugged together energy passes through electromagnetic  induction to the secondary. Or is it electromagnetic radiation?

Mid and high frequencies need the iron so that there would be no voltage drop at the primary of the output transformer. And possibly the circulation of magnetic flux?

Pleiades single ended class A 2N3055 continued

 At your risk.

The use of the somewhat big (size75mm) transformer with air gap and low ratio described on previous post makes possible a good quality sound with only a 12V battery.

But today a smaller size transformer made years ago rediscovered by chance produced a sweeter and better quality sound, more natural, easier and even smoother to the ear.

The size of this transformer is 60mm. Es are stacked together and there are 2 long screws keeping them together. While Is are stacked together and placed over the Es with no 3M Scotch invisible tape separating them. There is still of course a true air gap as metals do not fit exactly together.

Also thin wire is used by "mistake" on both primary and secondary.

Also and this is the most interesting point perhaps, the laminations are ordinary "thicker" laminations used on power transformers.

I thought there would be no extended high frequency response. By surprise there was amazing bass, mid and treble.

The experiment with this transformer sounds less loud but it sounds much better or listenable with musicality.

Signal path:

Constant Craving - K. D. Lang on CD - Sony CD Walkman line out - Pleiades 2N3055 resistor biased from collector to base, Vb=12V, Ic typically 60mA - Marantz Imperial 5-C with Tweeter setting at Low

Later addition:

Perhaps this comparison of the 2 transformers is not as relevant as it seems as the 2nd one has an inductance ratio of about 1.5H to 47mH i.e. is has a larger turns ratio. 

It is likely that popular music of recent years will be the classical music of tomorrow

 For example Constant Craving - K. D. Lang advances the art.

Moonlight Sonata - Beethoven is very characteristic of beginning with a minor chord and then the 2nd chord harmony is created by the bass going down one step of the scale while the upper parts played by the right hand remain exactly the same. It is the principle of least change in music creating a fantastic effect by this passing bass note.

In Constant Craving exactly the same thing happens with a great difference. This 2nd chord takes place as the 3rd chord while the 2nd chord is an ordinary one with a remote bass. So the 3rd chord takes place unexpectedly. But the brain of the listener somehow still relates to what was the 1st chord. 

I have not heard yet another music classical or pop that uses this harmony structure as on Constant Craving. If you know one please kindly post it at the comments below. 

Beginning harmony of Moonlight Sonnata.

Bass bD       harmony bA bC E

Bass bC        harmony bA bC E

Beginning harmony of Constant Craving:

Bass F         harmony  C F bA

Bass C         harmony C bE G

Bass bE       harmony  C F bA (equivalent to what tales place as 2nd chord on M.S.)

Bass bD       harmony C F bA

it can also be played:

(right hand notes played together higher than middle C notes);

C      F bA

C bE G

C bE F bA

C bD F bA 

All this intelligent harmony carries on from introduction to verse.