Retro Review: Terratec Promedia Base 1 - Part 1
17th June 2024
It's been a couple of months since I last did a retro review, and this month I'm looking at the Terratec Promedia SoundSystem Base 1 - a late ISA sound card from 1997.
Terratec Promedia SoundSystem Base 1
Bought in April 2024 for £14.35
Based on the Analog Devices AD1816 audio controller chip, it provided Ad Lib, Sound Blaster, Sound Blaster Pro and Windows Sound System support, and was Plug & Play. Terratec built some decent sound cards in its time, but this was where it all began - I've heard generally less-than-favourable things about the audio output of the AD sound chip, so it will be interesting to put this one through its paces.
Quick Visual Inspection
Looking around the card, it's a very simple design given that almost everything is handled within the Analog Devices chip:
- Analog Devices AD1816AJS SoundPort audio controller
- 2 x LM386 audio amplifier ICs
- A 33 MHz crystal oscillator
- An 8-pin EPROM chip
- A 26-pin wavetable header
- A 20-pin header for the Terratec Radio accessory
- Three 4-pin headers for AUX-in (CN1), Sony CD Audio-in (CN2) and IDE CD Audio-in (CN3)
- Three 4-pin headers for Speaker-out/Line-out (J1), Line-in (J2), and Mic-in (J3)
- Two jumpers at JP1 to set whether the audio out jack on the backplate will be amplified or not
- Faceplate with Audio-out, Line-in and Mic-in 3.5mm jack sockets and a 15-pin game/MIDI port
Date-wise, the only IC with a date stamp is the AD1816, which on this card is week 20 of 1997.
The Component Parts
The Analog Device AD1816AJS SoundPort
The "AD1816 SoundPort Controller" combines an OPL3 FM synthesizer, Sound Blaster Pro digital audio controller and an MPU-401 UART MIDI interface. It also has what Analog Devices called "Phat Stereo 3D" which is a 3D stereo enhancement which worked on phase-expanding an analogue stereo output - we'll look into that during testing. Oh, and it was compliant with Microsoft's then-new PC'97 audio standard.
It arrived in 1997, adding only the stereo 3D feature over the earlier AD1815.
Its built-in OPL3-compatible FM synthesizer provides 20-voice polyphony and is a hardware implementation of the Eusynth-1+ code developed by EuPhonics. Here's a list of the Analog Devices range of audio controller chips:-
| AD1848 | AD1846 | AD1815 | AD1816 | AD1845 | AD1819 | |
|---|---|---|---|---|---|---|
| Release Year | 1993 | 1994 | 1996 | 1997 | 1997 | 1998 |
| Sound Standards | WSS | WSS | Ad, SB, SBP, MPC Level 2/3 | Ad, SB, SB Pro, PC97 | WSS, MPC Level 2 |
AC'97 |
| ISA Plug & Play | - | - | Yes | Yes | - | - |
| Phat Stereo 3D | - | - | - | Yes | - | Yes |
| Hardware Volume Control | - | - | Yes | Yes | - | - |
| Power Management | - | - | Yes | Yes | - | Yes |
| MPU-401 Interface | - | - | Yes | Yes | - | - |
| Sample Rates | 5.5 - 48 kHz | 5.5 - 48 kHz | 4 - 55.2 kHz | 4 - 55.2 kHz | 4 - 50 kHz | 7 - 48 kHz |
| Modem Interface | - | - | Yes | Yes | - | - |
| Full Duplex | - | - | Yes | Yes | - | Yes |
Most of the devices in the range were geared toward providing Windows Sound System support to sound cards, with only the AD1815 and AD1816 providing Ad Lib, Sound Blaster and Sound Blaster Pro support. It also supports DirectX (DirectSound).
Audio Amplifiers
The onboard audio amplifiers are mono only (hence why there are two of them - one for each channel), and produce up to 1W output resulting in stereo amplification of 2W. It's slightly odd that Terratec didn't opt for the much more common TEA2025 stereo op-amp.
The ones on my board are the UTC386 from Hangzhou Youwang Electronics, which is pin-compatible with the NEC LM386.
EPROM Chip
The Atmos AT24C04 next to the crystal oscillator is a 4 KB EEPROM which allows for the storage of device IDs.
This is only used with the Windows drivers, and is used as part of the Plug & Play settings (including the device identifier) to be stored and recalled. Remember that almost all of the functionality of this Terratec card comes from the Analog Devices sound controller, which was designed to be sold to lots of sound card manufacturers, so this 'device identifier' part of it is what tells Windows that it's seeing a Terratec Promedia Base 1, rather than, say, a HighScreen Sound Boostar or an AOpen FX-3D card.
Terratec Accessory Header
The 20-pin right-angle header at the top of the card is for a Terratec ActiveRadio daughterboard that provides FM RDS radio capability to the card.
It has a few bent pins to sort out here - shame I don't have this accessory, as it would have been nice to see it running, and no doubt the software that came with it.
Wavetable Header
The 24-pin wavetable header is both Sound Blaster Wave Blaster and General MIDI-compatible and the Analog Devices chipset provides MPU-401 UART capability to this port. This opens up the card to be used with over 20 wavetable daughterboards that are compatible with Creative Labs' Wave Blaster.
Terratec released several of their own wavetable daughterboards called the Mini WaveSystem and Professional WaveSystem. The Mini WaveSystem offers 343 sounds in 8-Mbit ROM (1 MB) and provides 32 voices with 16 channel MIDI-multimode. The Professional WaveSystem came with a multi-effect processor (MFX) to create different 8 types of reverberation and 8 chorus to its 393 sounds, provided by the 32-MBit ROM (4 MB). Both used a Crystal/Dream chipset. These came bundled with Steinberg's MusicStation software.
The Crystal Oscillator
My card has a single 33 MHz crystal oscillator which uses integer division down to all the audio frequencies comprising 44.1 kHz (768 x 44.1 kHz), 22.05 kHz, and 11.025 kHz.
Despite the fact the chipset supports up to 55.2 kHz, the absence of a higher-frequency crystal tells me this card will not support the higher 48 kHz frequency, let along the full 55.2 kHz.
Headers and Jumpers
As I mentioned, this card is ISA Plug & Play, so there are no jumpers to set the I/O address, IRQ or DMA channels.
The white header block at CN3 is for an IDE CD-ROM drive's audio-in, with CN2 being the same for a Sony CD-ROM drive. CN1 allows an analogue AUX-in to be fed into the mix.
In addition, each of the 3.5mm audio jacks on the backplate have a complementary set of 4 pins behind them for Audio-Out, Line-In, and Mic-In.
The only jumper block at JP1 is used to select the audio output as "Line-Out" or "Speaker-Out". Line-Out mode would mean the onboard amplifier circuitry is circumvented so the output would be unamplified while Speaker-Out is amplified. Why are there two jumpers? One for the left channel and another for the right. The card is currently setup as Speaker-Out. For best signal-to-noise, it is usually preferable to use the unamplified "Line-Out" and connect the card to powered speakers or better still, a high-quality stereo amplifier, since a lot of noise is generated in a sound card's amplifier circuitry.
In Part 2, I will install the DOS and Windows drivers and test the audio capabilities of this nice little card.