At the present, eTAP2 and derived modules are already available for a while . A new project starting later in 2009 will emphasize on echo echo gear that can be connected directly between an electric guitar and an amplifier. This configuration is key for the on-stage performer.
To get started, a shortlist of potential delay devices is presented here. The mentioned devices are already studied in detail but selecting the device is part of the pending project's first phase. Obviously, selecting a device is also related to availability and DIY usability e.a. soldering etc.
>>>Although it's possible fully understood already. The multi-head/multi-amplitudes we are covering are rather unique in the present world of echo. The modern echo devices are mostly based om multi-tap same amplitude. The reader is requested to keep this in mind before making any call's towards initiating a DIY project so avoiding failure<<<
Some devices selected as our shortlist for further investigations are based on DSP or dedicated delay IC's:
- Bucket-brigade device BBD
These devices are regarded as mostly closed related to the workings of a magnetic medium as the sound travels in it's authentic state through the device from bucket to bucket, The S/N ratio is rather poor and the frequency range is to be < 8KHz to assure no clock frequencies, are interfering. For detailed information read the WIKI . Although this description is kept short it is the main goal of most developers creating multi-head echo equipment to apply array's of this device.
- PT2395
The PT2395 is a silicon gate CMOS-processed digital echo functionally compatibe with M50195P. Input signal is converted to the PT2395 by utilizing the onboard AD conversion and then stored in DRAM. As function of the clock frequency this soundsample will move through the DRAM and at a specific time, as controlled by the clock, be delivered to the outside world through a DA convertor. The unit is using a Codex based on the ADM algortim. The S/N ratio is with respect to BBD's much better.Using a 265K DDRAM the user can get more then 800mS @ 4Mhz clock out of this device. The actual configuration of the PT2395 requires a set of highly precise capacitors to be in conformance with the exact signal/noise specifications.
- PT2396
The PT2396 is a digital echo/surround processor IC utilizing CMOS Technology. Analog Signal inputted to the PT2396 is converted to digital signal by A-D converter and then stored into the internal memory. After a certain delay time, this memory-stored digital signal is converted back into analog signal via the D-A convertor. A low cost echo system may be achieved with the PT2396's A-D converter, D-A converter, incorporating ADM (Adaptive Delta Modulation) Algorithm while maintaining lower noise, lower distortion and higher S/N ratio. The PT2396 is functionally compatible with M65831P. If you are replacing M65831P with our PT2396, you must take note that PT2396 does not need to connect an external resistor (30 Ohms) to Pin 15 and Pin 21
- PT2399
Not a DSP but a very populair digital echo IC. This echo audio processor IC utilizing CMOS Technology which is equipped with ADC and DAC, high sampling frequency and an internal memory of 44K Digital processing is used to generate the delay time, it also features an internal VCO circuit in the system clock, thereby, making the frequency easily adjustable. PT2399 boast of very low distortion (THD<0.5%) and very low noise (No<-90dBV), thus producing high quality audio output. The pin assignments and application circuit are optimized for easy PCB layout and cost saving advantage.
- RA-FX3C
A low cost and high performance Digital Multi-Effects Module with Superior sound quality. it is pre-programmed with 16 built-in Reverb, Delay, Chorus, Flanger and Multi-Effects programs all 24-bit, 48 kHz ADC/DAC.
- SPN1001-fv1, a DSP device capable of creating multi taps/amplitudes to support our specific "vintage" requirements . for DIY project see here
The SPN1001-FV1 Is a complete reverb solution in a single IC as created by the developers of the Alesis Q2/Q20 DSP unit and presently owners and engineers of Spin Semiconductor. One of there distributors in the US is OCT who is also marketing a special daughter board that's featured with the FV-1 and includes 8 fully functional effects. It is possible to have a choise in 4 groups of effects pending your order. It's very simple doing business with them and payment can be done through Paypal.
With fully integrated stereo ADC and DACs, the FV-1 can be treated like any other analog component in your products signal path. The FV-1 can access a total of 16 programs, 8 are built in to the internal ROM and the designer may elect to connect a serial EEPROM with 8 additional programs. By using an external EEPROM, the designer can create a custom program set(8 programs) without the need for a microprocessor in the system. The rich instruction set allows users to program effects of all kinds. With instructions like LOG and EXP, users can easily program audio expansion and compression routines. Integrated digital LFOs and ramp generators allow for programming chorus, flange and pitch shift.
The unit is with 32K(8x4096) delay RAM and with the rich set of commands as part of Spin Semiconductor's development environment it is capable of providing the multi-tap/multi amplitudes functionality we require assuming the maximum required time is less then 1000mS.
- AL3101 and AL3102(serial interface only)
Are fast (50 MIPS), low-cost (under $4) digital signal processors from Wavefront, perfect for those applications where costlier DSPs would be overkill. Requiring only word-clock (up to 50kHz) as clock input, the DSP-1K offers 4 stereo inputs and outputs, internal program and data memory, log and anti-log instructions, and much more, all in a 300mil 16-pin SOIC (AL3102).
more on its way................
