When I started constructing my first DIY horn loudspeakers, I had to decide what material to use for building the loudspeaker enclosures. It is well known that the materials which a loudspeaker cabinet is made can affect to the sound quality produced by the speaker.
A kind of "Coloured sound" is the result due to the resonance of the cabinet walls.
This subject is often discussed among speaker manufactures, and there are lots of opinions if the material of the cabinet should contribute to the sound or not.

For my DIY horn loudspeakers i choose the FE206E driver by Fostex. Fostex recommended the use of plywood, that's why I decided to learn more about this material, and its sound insulation and damping characteristics.
Although I am not an expert in building loudspeakers I know that for building a well damped speaker cabinet there is a combination of strength, stiffness, surface stability and the sound insulation of the material.

What is plywood ?

Plywood is made up of thin multiple cross-banded veneers which gluing together to form a sheet. The nominal thickness of birch veneers is 1.4 mm and thick conifer veneers range from 2.0 - 3.2 mm thickness.

Coming soon to a rack near you ! a 6L6GC push pull tube amp with 12 tubes (6 tubes per channel !)

a project by Giannis Spathopoulos

DIY project by Christos Spathopoulos

• one 6L6 tube / channel
• simple construction
• excellent damping factor (Z)output < 1,9 Ohms
• pure class A
• 320 Volt plate voltage

Even though 6L6 tube is used primary in guitar vacuum tube amplifiers, many manufacturers use this tube in audiophile designs. I decided to build this small amp based on 6L6 vacuum tube using a classic single ended design.
The plate voltage is about 320 Volts and the output stage is a classic single-ended cathode follower. Output transformer is 4500 ohms and is set for 8 ohm speakers. We chose this design for one reason : Wiring this tube as tetrode we achieve the greater possible amplification as a result of higher grid transconductance.

Christos Spathopoulos

P.S. We will upload Schematic and data soon. Stay tuned ...

DIY speakers project by Giannis Mihailos
Well hello.
Those speakers I made are obviously a wilson audio watt puppy design. But except the looks, all the other construction is based on some other speaker designs. The speaker units I use are the famous scanspeak d2905-9700 non ferofluid tweeter the 18w8545 k00 mid bass and for the lower octaves the peerless hds 205. The project took me about 5 years to built and I mean of course not the construction which was ready in about 4 months but the whole thing plus the tuning of the xovers. Firstly I built a passive one for all the drivers but after some listening i decided that an active one at least for the lower section was something needed to use. So the today design has a series xover for the mid hi section and an active valve (marchand) xover for the woofers.

811A Parallel single ended amplifier by George Filippou

This 811A tube amp diy project designed by George Filippou and Giannis Spathopoulos, is the first attempt to work with 811A audiophile tube.

Based on Shishido 811A tube amp, the project is still in progress. You can find the shishido schematics in amp schematics pages and 811A tube data in tube data pages.

807 SE DIY Tube amps by costas sarris

My Parallel single ended 807 vacuum tube amplifiers at a glance :

• two 807 tubes / channel (parallel single ended)
• two independent power supply stages per Channel
• full tube rectifiers PSU
• excellent damping factor (Z)output < 2,0 ohms
• pure class A
• two independent lines for tube biasing
• CNC chassis design
• hand made output transformers P&K audio

In the summer of 2002 I decided to build a pair of mono block parallel single ended DIY tube amps, using the 807 tube. Actually, that was my third tube amp diy project. It all started with my decision to use the less known 807 tube, a tetrode whose features and sounds I was well aware of, from a specific DIY project (with one tube per channel wired in triode) made by Christos Spathopoulos. Christos tube amp played very smoothly in the whole spectrum (perhaps the best sound I had heard until then ) but unfortunately it lacked in power.

DIY Tube power supply project by costas sarris

This project was an attempt to build a tube power supply for my 6550 push pull mono blocks project. I already had a really ugly power supply in my rack and in early 2000 I decided to design and build from the scratch a new tube power supply.

The importance of choosing to use tube rectifiers for the power supply

As we know solid state diode rectifier circuits, are not very effective for tube amps, because they generate fast impulsion that pass through the circuit. Using a full wave tube rectifier circuit for producing direct voltage, we can prevent hum pulsations, and we can achieve more accurate filtering.

EL84 single ended Tube amp DIY project by costas sarris (2002)

Making a low power single ended amplifier has always been in my designing plans. Obviously such a construction requires the appropriate speakers, particularly horn type designs, so that the output of the amp can reach an efficiency satisfying level.
Once at a certain point, i came across the designs of the Decware SE el84 Zen amp, which had quite good reviews among the tube amps DIY and Single Ended tube amp builders.

DIY speakers project by costas sarris

In February 2006 after I had completed the construction of my dual mono PSE 807, me and George Filippou decided to build a pair of horn speakers using a full range driver in a back loaded horn design, which could easily drive by the 807 single ended & 811A tube amps, we had designed. We choose a design by FOSTEX with the full range unit driver FE206E which has been designed (according to the manufacturer) for use in back loaded horn type enclosures.

Although bass reflex projects have been presented by some manufacturers but this driver is generally unsuitable for bass reflex enclosures because of its over dumping characteristics.

Push Pull 6550 DIY tube amps project by costas sarris (1995)

The idea of building an audiophile vacuum tube amplifier based on high-quality materials begins in the early 90's. Initially had to answer the question "Classic Push Pull or a Single ended amp ?" So starting the design somewhere in 1994 I decided to design in a "white paper" a pair of monoblocks push pull tube amps with a power supply in a separate chassis which would not use solid materials but rectifier tubes.
In the first photo appears the two channels of my tube amps DIY design which consists of 2 mono blocks with a tube power supply in a separate chassis.