The key to Tannoy sound?
Trichecking if it really is 1Kv
RCA 833, specs:
Values per 833 working class B as an R.F. amplifier with a maximum modulation factor of 1.0.
Va max, 3 kV
Ia max, 400 mA
Pin max, 450 W (This is the total input power to each 833 at maximum drive.)
Pa max, 300 W (This is the maximum anode dissipation and at this power level the anode reaches a temperature of about 800 °C, and glows red hot.)
Vg1 max, -70 V
Peak R.F. grid voltage, 90 V.
D.C. anode current, 150 mA
D.C. grid current, 2 mA
Driving power, 10 W appx.
Output power, 150 W appx.
The king of SET amplifiers?
David, the importer of Shindo and other high end gear has been demonstrating a pair of Wavac HE833 monoblocs. Each amplifier uses RCA 833 valves. Direct-coupled input featuring a WE437A input tube and the driver is a triode wired KT 88.
So how does a 150Watt Single ended triode amplifier sound? I only listened to the Wavacs through Tannoy Westminster clones, pre and phono stages also by Wavac. Big sound, effortless dynamics, natural voice and strings. Good and clean from the deepest bass all the way to the highest frequencies I could hear. Most of the music we played was familiar, Beethoven and Vivaldi all the way to female and male vocal. The Tannoys of course looked and sounded great, having ample Single Ended Watts really made them sing.
In the pictures you can see the size and finish of the amps and the Tannoys. Also notice the Autographs made by Shindo.
MAXMEDIA Presents AVANTGARDE ACOUSTIC ZERO TA XD
This month we welcome to the club a local importer of High End audio equipment. Cameron Keating from Maxmedia will be presenting a selection of European Hi-Fi brands of which Avantgarde Acoustic from Germany, would be a very familiar name with horn speaker enthusiasts.
Cameron will be demonstrating the newest model in the Avantgarde range, the Zero TA XD. This entry-level speaker encompasses Avantgardes’ 25 years of know how in hybrid horn loudspeakers. Up until now, Avantgarde fans have had to choose between one of the company’s bigger, more expensive hybrid horns. Standing just over a meter tall, this new three way model is described as a semiactive horn system. The objective was to accomplish the clarity and power of its “bigger” brothers, in a significantly reduced enclosure.
Employing Avantgardes’ CDC technology, the midrange driver has no passive filter components in the signal path. This results in a sound characterized with an effortless clarity and explosive vitality. The 400 mm spherical midrange horn crosses over at 300hz to a DSP-controlled 10-band parametric subwoofer. This 12 inch long throw driver is powered by a 500Watt amplifier.
Partnering the speakers for the night, will be the LAB 12 Mighty Power Amplifier. This single ended class A valve amp, will be driving the mids and tweeters with only 10 Watts. Matched to its pre-amp, the LAB 12 TRUE is a Passive Attenuator / Input Selector. The LAB 12 DAC 1 will be taking care of the digital to analogue duties, with classic non oversampling (Phillips TDA 1543) and a tube based output stage. Not forgetting, a second DAC from iFi the Micro iDSD BL will be taking a turn. The font end source will be a music sever from INNUOS, the Zeneth Mk II.
With a system sensitivity of 104 dB, the ZERO TA is 32 times the dynamic range of a conventional 87 dB box speaker. I think we’re in for some fireworks for the night.
Nick Karayanis – Program Co-ordinator.
Melbourne Audio Club’s “Audio Action” group have finalised the unique transmission line speaker they designed and produced. The meeting is next Wednesday 21 June, as well as the AGM the new speaker will have it’s first public outing.
The Camel Project
Once again the Annual General Meeting has come around for another year. It is always the intention to keep business dealings at the meeting to a minimum, with nominations for Committee positions and Music Convenors.
After the club business, we will be entertained for the night by the guys from the Audio Action group. No, this isn’t a cabaret act, but a group of MAC members who have been lead by Ron Newbond in developing a speaker project. Over the past twelve months, the group has been collaborating in designing and building a ‘Camel’, well that’s what Ron calls it. The ‘Camel’ in question is actually a three way Transmission Line speaker, but not in the usual tall rectangular box shape.Well what do you expect when you get a dozen MAC members together to design a speaker?
This unique looking speaker is based around a cylindrical enclosure that houses the transmission line, while the front baffle presents to the listener a ‘surfboard shape’ that seems to float off the floor. You could even say the selection of drivers is unconventional. The tweeter is an air motion transformer (AMT), while the mid and bass cones are made from aluminium.
Ron will start the presentation with a short explanation on some of the technical issues with building such a speaker. How some of the challenges were resolved as well as why the group chose to develop this type of speaker. Then each member from the group will get to play a piece of music to the club. Ron assures me that the group will have a good selection of music that will demonstrate the best performance out of the speakers.Sounds like we will have an interesting and enjoyable night. Not to be missed.
Nick Karayanis, Program Co-ordinator.
After last week’s demonstration I checked Joe’s website
Www.customanalogue.com. ( note the correct spelling of analogue).
Lots to read and in investigate. He showed the frequency response, phase angle and impedance curves of his Elsinore speaker design. Worth a look, and certainly worth hearing of you get the opportunity.
Pictures of Joe will appear soon!
Next Melbourne Audio Club meeting Wednesday 17th May, in the Willis room, Nunawading Civic Centre.
The meeting begins at 8pm with reports of home meetings, other business tonight will be a vote on a change to the constitution. The presentation by Custom Analogue Audio and Joe Rasmussen JLTi will be of great interest to all Oppo users.
This month the club is very privileged to have an audio enthusiast travel all the way from Sydney to present at the club. Joe Rasmussen is known among the DIY audio fraternity as the “Father of the Buffered Gainclone” His collaboration with the late Allen Wright, led him to develop several projects starting back in 1975 with a “hybrid tube amplifier” In 2001 their work saw them develop upgrade modules for the first generation Sony SACD players.
Joe will be presenting at the club his latest upgrade projects. The JLTi Oppo level 4.2+ACB, is a highly modified Oppo-105D fitted with no less than eight modules. Each having a specific task – Master Clock – DAC Clock – Terra Firma power supply – all designed and developed by Joe at Custom Analogue Audio.
“Ultimate Digital playback deserves Ultimate Stability! This is about the importance of clocking CD players and digital playback, a new standard of performance. How to make digital sound more like good vinyl”
His collection of equipment that will fill the room with sound, will include two amplifiers, a prototype “Beyond Triode” amplifier – A New Type of Tube Amplifier, and a DIY 40 Watt “Transconductance Amplifier” This solid state unit will be brought along for a bit of fun. Designed to output ‘current’ it will be demonstrated with his Elsinore Mk6 speakers. Compatible with this amplifier they can be driven from any source impedance and hence does not rely on the ‘damping factor’ of the amplifier. The “Beyond Triode” amplifier encompasses thirty years of experience and developments rolled into one design. The prototype unit a Yaqin MC-100B, has been upgraded to give a great boost in the ‘Permeability’ of the output transformers, which then translates into an extreme level of resolution.
To round off the equipment list for the night, two versions of the JLTi Phono Stage will be presented, a single box unit, and the new Deluxe Phono Stage. The Deluxe version is a two-box unit with a ‘beefed up’ design in the gain and buffer stages plus a massive separate power supply with extreme filtering that reduces power supply noise.
What Joe Rasmussen has achieved by taking a good quality product, amp or CD player, and lifting its performance to more than just one level, but several, makes music sound just lovely-Just Listen To it.
Nick Karayanis – Program Co-ordinator.
Next Wednesday we will experience rhe new turntables designed by Mark. His last talk at the Melbourne Audio Club was one of the best presentations I can remember. Informative and very interesting.
Wed 19th of April, 8pm in the Willis Room, Nunawading.
MARK DOHMANN with his HELIX 1&2 TURNTABLES
Back in October 2013, the club was very privileged to have one of the most influential audio engineers of the analogue world present at the Melbourne Audio Club. He is Mark Dohmann, the man who designed the Continuum Audio Labs Caliburn turntable and Cobra tonearm. The Caliburn set a new benchmark when it came to sound quality; even Stereophile Magazine had to give it a new rating, A+, as well as “Product of the Year” for 2006.
Mark has moved on from his involvement with Continuum Labs, and has formed Audio Union, a collaboration with Thrax Audio Ltd to bring his latest statement turntable to the “High Fidelity” market. The Dohmann Helix 1, is the result of complex and advanced engineering technologies, that takes it to the next level in turntable design. The Helix 1 features a radical approach to advanced motion control to the motor and platter. Another innovation is in the complete integration of a customised negative stiffness isolation system, which results in an ultra-low natural resonance, 1.5Hz in the horizontal plane and 0.5Hz in the vertical.
The Helix 2 turntable is so new, it doesn’t appear on his web site. As far as I am aware, this will be its first public showing. Quite an honour for the club. Another first will be the new addition to the Thrax portfolio of equipment. The LYRA loudspeaker will make their debut at the club partnered with a pair of HEROS 100W class A mono blocks and the matching DIONYSOS pre-amp. The Lyra is a two-way, three driver monitor sporting a vented enclosure that is made of aluminium plates, screwed together. The D’Appolito array on the front panel, incorporate two 6.5” woofers with magnesium membranes and copper phase plugs. The tweeter is a ring diaphragm compression driver crossed over at 1.5 kHz. Its shape was developed by Spherovox with specific directivity and frequency response.
“Helix 1 rewards the listener with the closest facsimile to the master tape. Its design is a significant enhancement on state of the art and its motion control defines what will become part of a new breed of “Super Turntables”.
Nick Karayanis – Program Co-ordinator
Ikutaro Kakehashi the founder of Roland and instrumental in the design and implementation if MIDI has died.
To hear the Helix 1 and Helix 2 come to the April meetong of the Melbourne Audio Club. Mark Doehmann is expected to bring both turntables to the Willis room. Make a note- third Wednesday of every month
Ron Newbound and the DIY group of Melbourne Audio Club have been developing a new transmission line loudspeaker. As a group they came up with a design using tapered Sonotube pipes within the enclosure. Drivers and damping have been installed, crossover design and tweaking are planned for the next meeting. (On April 1st. Not an omen I hope).
If you would like more information come to the meeting Wednesday 15 and join the group. Also enjoy the demonstration of Hugh Dean’s AKSA amplifiers and Kef 105 reference loudspeakers brought by Ray of the Hi Fi Exchange.
8pm in the Willis Room, Nunawading Civic Centre. Third Wednesday of every month