Sydney Audio Club Meeting - December 2025
Sunday 14th December 2025: The December meeting will feature a vintage BOSE 901 Series IV floor-standing speaker system, produced from 1978 to 1983, courtesy of member Philip Miles.
The December meeting will also include our Christmas BBQ and Guessing Competition
There will Not be a TechTalk this meeting.
The doors will be open from 12:00pm for the BBQ and to meet and chat with members, before the Guessing Competition and music sessions commence from around 2:00 to 5:00pm.
The December meeting will also include our Christmas BBQ and Guessing Competition
There will Not be a TechTalk this meeting.
The doors will be open from 12:00pm for the BBQ and to meet and chat with members, before the Guessing Competition and music sessions commence from around 2:00 to 5:00pm.
Dear members and friends of Sydney Audio Club Inc.,
The next Sydney Audio Club meeting on the 14th of December is our Annual End of Year BBQ and the Traditional Guessing Competition with Prizes to be won. Please bring along pre-loved equipment eg. Cables, CDs, LPs, HiFi gadgets etc. to donate to the prize pool (further details later in the bulletin.)
The doors will open from 12 midday for the BBQ. Please bring $10 for the BBQ which includes food and a drink + 2 raffle tickets. Extra chances to win prizes are available at 1 ticket for $5, 3 tickets for $10 or 5 tickets for $15. Some prizes are quite valuable. Wives, partners or extra friends are invited as well.
There will be no TechTalk this month however our esteemed club member Philip Miles will be presenting his vintage complete Bose system and some late 70s music to make them feel happy.
Details of the System:
The Bose 901 Series IV is a vintage, floor-standing speaker system produced from 1978 to 1983, known for its unique Direct/Reflecting sound technology and reliance on a mandatory external Active Equalizer.
Key Features & Technology
The Bose 1801 power amplifier is a vintage, high-power solid-state stereo amplifier known for its robust construction and high power output, originally designed to power the Bose 901 speakers. It is a highly collectible item among audio enthusiasts.
Key Features and Specifications
The Bose 4401 is a classic, highly collectible solid-state four-channel preamplifier produced in the 1970s, known for its robust build and performance when paired with the Bose 1801 power amplifier and Bose 901 speakers.
The Bose 4401 preamplifier is primarily a quadraphonic unit designed to handle four channels, offering a unique listening experience for its era.
The next Sydney Audio Club meeting on the 14th of December is our Annual End of Year BBQ and the Traditional Guessing Competition with Prizes to be won. Please bring along pre-loved equipment eg. Cables, CDs, LPs, HiFi gadgets etc. to donate to the prize pool (further details later in the bulletin.)
The doors will open from 12 midday for the BBQ. Please bring $10 for the BBQ which includes food and a drink + 2 raffle tickets. Extra chances to win prizes are available at 1 ticket for $5, 3 tickets for $10 or 5 tickets for $15. Some prizes are quite valuable. Wives, partners or extra friends are invited as well.
There will be no TechTalk this month however our esteemed club member Philip Miles will be presenting his vintage complete Bose system and some late 70s music to make them feel happy.
Details of the System:
The Bose 901 Series IV is a vintage, floor-standing speaker system produced from 1978 to 1983, known for its unique Direct/Reflecting sound technology and reliance on a mandatory external Active Equalizer.
Key Features & Technology
- Direct/Reflecting Technology: This is the core innovation of the 901 series. It uses a unique design with nine full-range drivers per cabinet, with eight facing the rear wall to reflect sound and one facing forward to provide direct sound. This approach aims to replicate the mix of direct and reflected sound found in a live performance, creating a wide, room-filling soundstage rather than a pinpoint stereo image.
- Active Equalizer: The system requires a dedicated Active Equalizer, which must be connected within the amplifier's signal path (e.g., in a tape monitor loop or between a preamp and power amp) to correct the speakers' inherent frequency response. The Series IV equalizer was the first to use an op-amp based design and features controls for low filter (-5dB @ 40Hz), mid-bass (+/- 8dB @ 250Hz), and treble shelving (+/- 8dB @ 10kHz) to compensate for room acoustics and personal preference.
- Full-Range Drivers: The system uses nine 4.5-inch full-range drivers with an aluminium helical voice coil, designed to handle high power without distortion. The crossoverless design contributes to a coherent sound.
The Bose 1801 power amplifier is a vintage, high-power solid-state stereo amplifier known for its robust construction and high power output, originally designed to power the Bose 901 speakers. It is a highly collectible item among audio enthusiasts.
Key Features and Specifications
- Power Output: The amplifier delivers a substantial 250 watts per channel into 8Ω (stereo) and 400 watts per channel into 4Ω.
- Design: It uses all silicon solid-state circuitry with 14 power transistors per channel and features a massive 2.0kW power transformer and extensive heat sink area for cooling.
- Dimensions & Weight: The unit is large and very heavy, with dimensions of approximately 7-3/16 inches (H) x 18 inches (W) x 18-1/2 inches (D) and a weight of 82 lbs (about 37 kg).
- Display: The 1801 model (unlike the professional 1800 variant) includes large, amber signal meters (VU meters) and a power monitor display using an LED array.
- Protection: It employs fast-acting electronic protection circuits for current limiting.
- Frequency Response: The frequency response is rated as 20Hz-10kHz ±.25dB and 10kHz-15kHz ±.7dB.
- Total Harmonic Distortion: Less than 0.15% (20Hz-5kHz) at 250 watts.
The Bose 4401 is a classic, highly collectible solid-state four-channel preamplifier produced in the 1970s, known for its robust build and performance when paired with the Bose 1801 power amplifier and Bose 901 speakers.
The Bose 4401 preamplifier is primarily a quadraphonic unit designed to handle four channels, offering a unique listening experience for its era.
- Design: It is a solid-state preamplifier, often found with an external wooden case.
- Inputs: It features four high-level inputs and two phono inputs, catering to various audio sources including turntables.
- Decoding: The unit includes an integrated CD-4 decoder (CDM-1) for quadraphonic sound.
- Controls: It has balance and fade (front to back) controls for each channel, allowing users to adjust the sound distribution in a four-speaker setup.
After the guessing competition and prizes and Philip’s music selection, the second half of the music session is designed to help you evaluate the system with music that you are familiar with. All members and guests are welcome to offer music to share with us all. For this meeting you may bring some music via USB and the club’s Reavon player will also be available to play CDs.
All we ask is that the music and recordings be interesting. We'll ask you to tell us a little about the artist/recording before it is played. Tracks over 5 minutes will be faded out, to give everyone a fair go.
Whether you are a novice or a seasoned veteran, you will have the opportunity to listen, learn and share your experiences with others. Feel free to come and hear the capabilities of the system, or to just share the experience with like-minded music lovers in a friendly and relaxed atmosphere. Guests are welcome – we are a very friendly club so you don't need to know anyone to join us for an afternoon of fine music and sound.
Venue: Mathews Room, Epping Creative Centre, Dence Park
Address: 26 Stanley Road, Epping
When: Sunday 14th December
Doors open from 12:00 pm to meet and chat with members and the BBQ followed by the Guessing Competition to win Prizes. All the Prizes will be displayed on a table with the names of the donor companies and prizes can be selected in order as tickets are drawn. if your ticket is drawn. The first few Prizes are for members only.
The Bose Presentation starts around 2:30 pm and the meeting will finish at 5pm. If you need to stretch your legs during the afternoon please wait for a break between tracks to prevent any interference with other members’ enjoyment.
To our guests, we respect the music being played so please refrain from talking while the music is on. You will find there are chances for plenty of happy banter between tracks.
It is a requirement of entry that you sign-in in the visitors’ book.
Hope to see you there on Sunday 14th.
John McEvoy
Meeting Co-ordinator
Sydney Audio Club Inc.
All we ask is that the music and recordings be interesting. We'll ask you to tell us a little about the artist/recording before it is played. Tracks over 5 minutes will be faded out, to give everyone a fair go.
Whether you are a novice or a seasoned veteran, you will have the opportunity to listen, learn and share your experiences with others. Feel free to come and hear the capabilities of the system, or to just share the experience with like-minded music lovers in a friendly and relaxed atmosphere. Guests are welcome – we are a very friendly club so you don't need to know anyone to join us for an afternoon of fine music and sound.
Venue: Mathews Room, Epping Creative Centre, Dence Park
Address: 26 Stanley Road, Epping
When: Sunday 14th December
Doors open from 12:00 pm to meet and chat with members and the BBQ followed by the Guessing Competition to win Prizes. All the Prizes will be displayed on a table with the names of the donor companies and prizes can be selected in order as tickets are drawn. if your ticket is drawn. The first few Prizes are for members only.
The Bose Presentation starts around 2:30 pm and the meeting will finish at 5pm. If you need to stretch your legs during the afternoon please wait for a break between tracks to prevent any interference with other members’ enjoyment.
To our guests, we respect the music being played so please refrain from talking while the music is on. You will find there are chances for plenty of happy banter between tracks.
It is a requirement of entry that you sign-in in the visitors’ book.
Hope to see you there on Sunday 14th.
John McEvoy
Meeting Co-ordinator
Sydney Audio Club Inc.