A battery powered high quality sound reproduction system from phono cartridge to loudspeaker

At your risk. Please take all safety precautions. A battery must be connected in series with a suitable fuse to avoid skin burb in case metal jewelry is worn or avoiding fire hazard.

This system combines previously described Pleiades amplifiers.

It was put up together today for the first time with phono channel out of phase connection corrected and with the RIAA cooking corrections in order to correct overal preamplifier response as described on previous posts.

Preamplifier and power amplifier are operation in class A (electrons flowing all the time, even when there is no music playing).

Total number of transistors used for each channel is 4, 3 K117 JFETS for the preamp operating in low gain with local feedback (source resistors unbypassed) and one 2N3053 on very small heatsink for the power amplifier with zero negative feedback.

Both the phono preamplifier and power amplifier have an output transformer. The power amplifier has a relatively small ferite output transformer with air gap separating the 2 E sections as there is DC current flowing in the primary. Toilet paper is used for the air gap and Siemens Es anre secured together with metal clamps fastened with bolts and nuts.

The DUAL CS-627Q direct drive turntable is battery operated too with same voltage as the power amplifier. 24V from two 1.2Ah powering both turntable and stereo power amplifier.

The hono preamplifier is powered by two 9V batteries.

Power consumption is very low, current consimption is about 20mA for the stereo power amplifier now than the ambient temperature is high, 14mA in the winter. The turntable consumes about 100mA. the phono stereo preamplifier about 2 mA. So total power consumption is somewhat more than 2 Watts.

Power output should be of the order of 100mW yet it sounds surprisingly loud with huge bandwidth and no need was found in today's listening tests for higher volume in a small bedroom with speakers at about 2m or less from listening position.

Signal path:

CD or vinyl records - Sony CD Walkman D-EJ758CK or Dual CS-627Q with original Ortofon cartridge and new stylus - Pleiades 3 K117 phono preamplifier - Pleiades 2N3053 power amplifier - Celestion Ditton 150 loudspeakers - small room with 3 Pleiades membrane (bitumen felt) bass absorbers inside white painting stretched canvas frames of 3 different dimenssions 

CD used is The Year of the Cat - Al Stewart

Records used: Only Love LP - Nana Mouskouri

                        Brothers in Arms LP- Dire Straits

                        One Day in your Life 7" single - Michael Jackson

                        Take a Look - Natalie Cole double LP

The sound quality was amazing, breathtaking with huge bass, smooth mid and very extended treble about 3 more octaves than listening to YouTube, at least one more octave than listening to CD. About at least one more octave that listeningto other CD systems even very high quality ones yet without the harshness. 

Anbience sounded amazing.

And strings did not sound harsh at any time. This is possibly due to the fact that the passive RIAA filter comes immediately after the low gain 1st stage. Therefore clipping of the extreme content of high frequency due to preemphasis on records is avoided, see previous posts on the Pleiades 3 K117 design.

The whole system was exremely quiet no noise or hiss heard at any time even when volume control is at max and no record is playing.

Very impressive is how exteded treble sounded with no harshness, the deep bass and smooth liquid midrange.

The power amplifier is just one transistor for each channel.

   

Equal Loudness Curves can be translated as Καμπύλες Ισης Ακουστότητας

Ωκεανός - Ναντια Διολιντζή Lyrics, Γιωργος Τσακίρης music, Ocean - Nandia Diolingi, George Chakiris, elements of the song

In B minor.

Bossa nova.

Step down bass.

Bass Code (Bach figured bass notation):

B

A6

G7

F7

modulation to E Dorian

E

E46

Example melody with lyrics:

-   B   D   -            στα - γο           chords   (harmony) B D #F

B  -     -    A           να      πεύ-                    

o   B   ο    -            τω                                                  A  #C #F       

-    -     -    E          βυ-

F   D   B    ο           θί - ζο - μαι                                   G B D #F

-    -     -    Α           στον

-    Β    Β   Β          ω-κε-α                                          #F A #C E

Α    ο    Β   ο          νό σου

.   .    .

-   -   B   A              κρά -τα                                           E G B

B  -   -    A

o  o   B   o                                                                     E A #C

A simple MOSFET power amplifier with just a 12V battery, a potentiometer and resistor for bias, an input coupling capacitor and no output transformer

 

At your risk. It may blow your spekaer if  a protective fuse is not connected in series etc.

Please see previous post on Pleiades K951 amplfier with speaker connected directly to the drain of the MOSFET.

Update on Pleiades K951single MOSFET zero feedback single ended power amplifier

 

At your risk.

Today the bifilar 1:1 output transformer was disconnected from drain and connected to the source. This was done fairly quickly as all connections are done with Wago snap terminal connectors.

Source follwer configuration worked with change with readjustment of bias from the 50K potentiometer in series with 47K  but sensitivity was low as there is no voltage gain.

Signal path:

CD - SONY CD Walkman - Pleiades K951 as source follwer - Marantz Imperial 5C

So power suppling the speaker was low.

The amplifier was remodified to drain follower.

Then the output transformer was removed and the AKAI SR H-44 speaker connected directly to drain instead of a load resistor. This should not blow the speaker if drain currect (which now passes through the voice coil) is kept by suitable bias to up to say 300mA. It worked and sounded nice, but less loud than when using the output transformer due to loss of efficiency.

Betasilk or Betaplast etc

 

At your risk. This is not a medical or dermatologist advice. Betadine cream is not suitable for persons with thyroid problem.

Combining 2 products together to create a new product. 

Hansaplast with Betadine cream.

Hansaplast moistened with Betadine cream applied on skin spots may vanish the spot if applied overnight(s) or during the day. 

Betadine cream softens the spot until it breaks, it disinfects and the Hansaplast tisue absorbs.

Thsi idea comes from adapting my dermatolosgist Yiannis Peros' advice when I had a serious skin infection.

 

Merino Wool t-shirts

At your risk.

One of the best thing bought this year. Black long sleeved.

They are 3 times more expensive than cotton but they last at least 3 times more.

Minerva brand.

They keep you warm in the winter, dry on both seasons.

When the is heavy air conditioning in the summer, you are saved as you are dry before entering the air conditioned environment and you don't feel cold.

Dryness in the key.

And they feel compatible with one's skin.