newly received or noteworthy information, esp. about recent or important events :  

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Antique Telegraph key

Summer 2021

PIO Filter Capacitors in conjunction with IIXO

x-over for the mono setup

A bunch of antique PIO capacitors added to the IIXO, some of them paralleled to a total of 10µF are used as a filter in conjunction with the 0.44mH coil for the 2420 driver. The T90A tweeter has been replaced by the BMS4526/16Ω driver and connected directly to the amp output via a second order HP filter.

That changes the IIXO arrangement as seen in the picture. Characteristics are as below. 

Bass 784 Hz 1st order slope

2420 1KHz 2nd order

BMS4526 10Khz 2nd order


 It is of great importance that the iixo ‘’transformer’’ has to be away from the strong magnetic fields of the drivers, alternatively it should be magnetically shielded.

Schematic of the three way for mono setup of the x-over.

Fall 2020

Mobile Public Address System

Public Address system as used in a much beloved movie

Eighties, two way concentric horn-loaded, Public Address system as used in a much beloved movie.  IMDb

Summer 2020

The DMM Club in 2020 Convocation

DMM club

It was late 70’s early 80’s when the record industry made a move with DMM, a new ‘’much promising’’ product, hoping to eliminate the newly DIY production rise for vinyl records. The chosen repertoire for that escapade was exactly what the young potential customers were avoiding. Furthermore the DMM mastered records sounded tiny, thin and harsh somehow like the early CD’s.

Fear no more as todays vinyls are mostly direct to metal (cooper) cut/mastered and there is even a company that sells cooper plated positive masters as playable records.

Summer 2020

New Address

Μεταφοραί, εκδρομαί ο Θείος του Μήτσου.



Getting the new years crop to a new provider at a new destination hoping for a better future.

Summer 2020

Happily Surprised 

Once More

900Hz IIXO coil X-over.

Once again I had a nice surprise trying the ‘’iixo’’ coil X-over after the instigation of dear friend, mentor and excellent horn builder Martin Seddon. 

On the left there is a schematic with taps for HF driver level adjustment. 

For more info please click.


Spring 2020

Vital Announcement On Grounding

Lately I see many quacks selling boxes and other devices for earthing purposes, promoting a noiseless system. This earthing scheme is good and safe only for one diode/high-Z earphone radio. 

In case you want to complement your system with such an “earth” get ecological and buy a pot with a water-thirsty plant. Drive a nail in the pot and connected it to a wire, connect the other end to an earth post in your system.

PLEASE for no reason omit (cut) the ground from your system or your sockets.

Please note that in most places in the world the electric provider connects the neutral to the ground in the mains/fusses central panel, so the earth becomes ground.

If you feel restless and think that the noise in your system comes from the ground itself and not from your messy connections (ground loops), you could create a complimentary technical ground (just for your system) using the water pipe system in you place, only if you are sure that it is all metal and is connected this way to the local grid. 

 You could alternatively drive a bronze or copper rod 2cm thick and 1,5m long in you basement or garden in a moist place and connect the rod to your system with 3cm Ø, flat, tinned, braided wire (that’s the signal corps way for field grounds).

There are more elaborate ways for grounding schemes but you need to dig a large hole in the ground and burry a bronze or copper plate (2sq meters) and then fill the hole it with a pulverised mixture of carbon and marble (CaCO3).Please note that these grounding schemes have a limited life span.

Please also note that the connection of the braided wire to the ground device has to be donne in a mechanical way like a copper/bronze screw or a collar.

NEVER BUT NEVER connect your ground in a lightning protection system if such exist.

To conclude, the best way is to ask a professional to instal and sign for the extra ground so someone will be in charge of the consequences following an accidental death.


Spring 2020

The Azura AH-550 horn is a hands down winner.

The JBL 2370A horn for the 2420 driver has been exchanged 

 with the excellent AH-550 AzuraHorn that improved the diffusion of the sound and the spectrum of the radiated frequency from the driver. The AH-550 horn is a hands down winner and trust me I have tried many horns used in professional PA systems.

Summer 2019

The Best Little Enhancer For Your System Money Can Buy

The Best Little Enhancer For Your System Money Can Buy

In case that you’ve spend a fortune or less for your sound system and your hand is still itching for more expenses (AKA improvements) there is something I would recommend that can add value and safety to your system.

Recently I have done extended research and studied a lot of enhancers, purifiers, resonators, dummy earthing, demagnetisers, cookers, sticks and stones that promise magical results to your sound system. After in depth research and analysis I came to the conclusion that the best enhancer is the blue evil eye bead amulet that can not only protect you from the evil eye but also from stray radiation part of the known spectrum and from the one that is not yet discovered, it also enhances and refreshes you listening area.

Please note that the blue evil eye bead amulet existed long before the invention of electricity with great results for the believers.

Spring 2019

Two Way Single Loudspeaker For The Monophonic Setup

2420 HF driver with the 2370A horn.

This is the single loudspeaker for the monophonic setup.

 It consists of the JBL 2420 HF driver with the 2370A horn, the 2206 12’’ woofer and a pair of second order Linkwitz-Riley filters one HP and one LP.

The enclosure is a 70 litre box of slot vented type.

Winter 2019

How To Turn A Stereo Cartridge Into A Monophonic one

How To Turn A Stereo Cartridge Into A Monophonic one

A trick that I picked from my MW radio days is how to turn a stereo cartridge into a monophonic one.

Well it is pretty simple, you just have to short the cold right channel out to the hot left channel out, then you connect the hot right and the cold left to your mono amplifier/preamplifier.

Don’t forget to adjust the R-load accordingly.

Fall 2018

Mono Turntable

The turntable was matched with a Karmadon remake of the Gray 206 tonearm and a  DENON DL-102 cartridge.

As the monophonic ‘’RCA’’ phono preamplifier would feel lonesome I had to pair it with a mono ‘’vintage’’ turntable.

The choice was easy as a Garrard 401 was my favourite pick.

The turntable was matched with a Karmadon remake of the Gray 206 tonearm and a

 DENON DL-102 cartridge.

Summer 2018

A Vanity Affair

MONO Tube preamplifier.

Now that the digital audio technology has reached its peak and anything sounds like everything, I felt the urge to step back to the day mono ruled.

So much technology, so many developments since the monophonic days and still most MP3s and Youtube videos sound like a coffee grinder.

Well, besides all that, stereo always got on my nerves every time I would listen music in a car or in a bar, as I had half of the music, usually the half that was on the speaker, near to me. Not to mention that most of the times I listened to music I was engaged in at least one more activities, sitting or standing far away from the stereo sweet spot. Being pined down and just listening to music always seemed to me like the clockwork orange torture. 

The idea of building this mono phono preamplifier that is based on an old RCA schematic I came across in the net was not hard to resist. The schematic includes four different equalisations for old LPs. 

Back to Mono?

Summer 2018


island records , sheila hylton

As much I hate to grumble there are things that have to be said.

I can understand and accept those people that collect records as others collect stamps, matchboxes, mugs or other useless stuff. What I do not comprehend is the urge of those misinformed trending hipsters that spend a kings ransom for turntables and dedicated preamplifiers for a troublesome, almost useless medium, as vinyl.

I do recall the days we used to send the master tapes to the record plant for production and what we got back (white label, test pressings) was something a lot different to the original recording. I do also remember cutting the lathe several times till we could compromise and get an acceptable result. Needless to mention the narrow frequency response, the limited headroom and the high surface noise. All these make me believe that it is totally stupid to resurrect a medium that is so limited and has nothing to do with ‘’high fidelity’’.

The problem is even greater for the new production of vinyl records as they are mostly cut with some eastern block leftover lathe cutting machines, and then print in 200 plus grams records with superficial grooves. Those unacceptable records have grooves that are thiner than the scratches in my favourite well played records. (Thin grooves means lower volume, easier destroyed records and higher noise to sound ratio). 

And as if the neo-vinyl curse was not enough there is another trend for those with deep pockets and their mouth in the place of their ears. That moronic trend is the lust for open reel tape recordings. I was always wondering what is the source of those recordings, as some of them are from the sixties and seventies, and how they are mass reproduced to open reel tapes.

  Here I have to mention that the problem with the tapes is that they have limited lifespan and that they self demagnetise and rot.

They need a storage environment that is controlled in humidity and temperature, away from strong magnetic fields, and to be kept tails out for the print through phenomenon. Even so they have to be baked from time to time in order to get revived.

These are only the problems with tapes, troubles pile up with the maintenance of the tape recorder/reproducer. 

In the good old analogue studios there was an in-house maintenance engineer whose main tasks was to keep among the other apparatus, the tape recorders up and running and in good shape. So think twice before getting involved in the open reel madness.

Summer 2018

Another X-lent MC Step-up  Transformer

sowter 9990 cartridge step-up transformer arrangement.

It is for certain that the 9990 is an X-lent step-up  transformer for MC cartridges. With a nominal ratio of 1/20 it is a match made in heaven for my DL-103r cart. Neither a correction filter nor a load adapting resistor were used.

 Even better, the best future of this transformer is that you don’t have to sell a kidney and half of your liver to get it. 

For more information about step-up transformers

 follow the Link.

Winter 2017

Preamplifier with RIAA filter.

This is a sneak preview of the newly designed  preamplifier. It consists of two chassis, one for the pre that includes a RIAA and one for the power supply.

 For more info on preamps click to link.

Winter 2017

Preamplifier with EC8010 tubes.

  This is a newly designed  preamplifier, constant current source loaded, with a pair of EC8010 tubes. The frequency response measured is dead flat from 10Hz to 36Khz. It is of para-feed design, the output transformers have a 5/1 ratio with 15KΩ primary and 600Ω secondary. This new improved version employees a pair of SOWTER 1010/1701b transformers for peace of mind and for better lower end.

Winter 2017

RIAA preamplifier, with a quad of 5842 tubes

  Planing and building a new RIAA preamplifier, constant current source loaded with a quad of 5842 tubes.

 For RIAAs click to link.

Spring 2016

Amp. with 2A3 output tubes and E86C drivers

The new amplifier named Aura is finished and tested It uses 2A3 output tubes and E86C drivers .

Click to link and discover how m-amplifiers are built.

Loudspeaker commission on a shoestring.

 A commission on a shoestring was the building of a pair of bass reflex  loudspeakers employing the Visaton BG20-8 drivers in a 30 lit. enclosure tuned @ 40Hz. 

  For more information on loudspeakers please click to link.

Fall 2015

Parallel feed, 300B amplifier.

  A new , parallel feed , tube amplifier employing the 300B as output tube.

There were no shortcuts for the components used in this amplifier , on the contrary it is a ridiculously over-designed and  heavy amplifier for its 2 X 5 watts output . 

Heavy is also the CO2 footprint of the amp and it certainly does not conform to DIN.

Winter 2016

Summer 2015

Happily Surprised 

One of the few thinks that happily surprised me over the last years, besides the One Electron UBT-3 transformer, was the 

JJ 2A3 tube

 I was always skeptical about the products from behind the former iron curtain countries as if I were to buy me a car.

 I would never but never get me a Scoda, Wartburg or Volga. You might say tubes and cars have nothing in common but let me note that the production mentality is the SAME.

 To cut a long story short I did an a/b/….n test with several 2A3 tubes and the winner, hands down, was the Slovak JJ 2A3 that still has to prove its value in time depth.

2A3 tubes, Smal format.
2A3 tubes, Large format.

 The tubes under test were : CVC, Fivre, Sovtek. Shuguang (Small and Large glass envelope), Emmision (solid and mess plate) and of course the JJ 2A3.

  In my opinion the CVC, antique Fivre and Sovtek are good enough for target practice. The Shuguangs are acceptable in case you like harsh high frequencies. 

 In the league of the big boys, Emmision and JJ, the JJ sounds fuller with excellent lows and airy, clear highs. The second runner up was the Emmision mess plate with a more ‘‘constrained’’ smooth sound. All of the big boys have thick crystal glass envelop as some one would expect from the famous glassware tradition of Czechoslovakia.

 Please don’t forget that the opinion about those tubes is clearly subjective but based in objective study.