DSP

[gbono]

Any historians out there who can comment on  MI amp designs that FIRST used DSP?  Also interested in comments on the early DSP chip suppliers.

[teemuk]

In what kind of application? Regular effects processing or "modeling" ...?

How would you draw the line between DSP-based distortion / waveshaping effects and EQ:ing, or the whole concept of trying to "model an amp" using the said means?

[Enzo]

You want to include things like chorusing with the MN300x series of chips?

[gbono]

Let's stay with distortion, waveshaping FX and EQ - I'm assuming that these were the first applications of DSP designs in MI amps?

MN300x from Panasonic? Analog "bucket brigade"?

[gbono]

Okay, what about a specific question in regards to early DSP designs in MI amps?

Fender Stage 100 DSP circa 2004(?) Where does this amp fit in to the timeline? What did Fender do with DSP before the Stage 100?

[g1]

 When I think of DSP for earlier stuff I think of eprom's etc. with stickers on them that stated their version number.  One of the first pieces of guitar type gear that could be "upgraded" software wise via eprom that I recall was the ADA MP1.
  If anyone remembers the pages of factory mods those went through, it was quite extensive.
Hope that counts even though it was only a preamp.

[gbono]

ADA MP1 would have been early 90's??? Who supplied the chip set?

Fender has the  Dyna-Touch™ Plus DSP amps in 2002 (any DSP designs for Fender before 2002?) Looks like Fender is using TI chips  in 2002.

[Enzo]

Fender Cyber-Twin dates from 2000.

[Kaz Kylheku]

Bucket brigade delays (BBD's) don't count because they are discrete time analog: the amplitude is represented by capacitor charge, not by 1's and 0's.  Digital means discrete time and discrete amplitude.

ADA MP-1 (which, incidentallly, has a BBD as the basis for its chorus) is not a digital signal processor at all. All signal processing is analog. The processor just stores and establishes gain/volume and signal routing settings for various circuits.

The MP-1 can be summarized as:
* Discrete FET input stage followed by a programable attenuation feeding an op-amp buffer with soft diode clipping driving either a tube channel or SS channel
* a four-triode (2 x 12AX87/ECC83) tube board with two FET-switched voicings and a programmable attenuation between the second and third stages.
* solid state channel with NE572 compression chip
* a master volume section shared by both channels feeding into a four-band EQ based around a quad op-amp
* a chorus based on an MN3007 bucket brigade chip, with a NE570 compander around it for noise reduction ("stereo" achieved by inverting the chorused signal into the other channel).
* switchable effects loop after EQ, before chorus.
* all glued together with op-amp buffering running on -15/+15 rails.

[phatt]

Bucket brigade delays (BBD's) don't count because they are discrete time analog: the amplitude is represented by capacitor charge, not by 1's and 0's.  Digital means discrete time and discrete amplitude.

ADA MP-1 (which, incidentallly, has a BBD as the basis for its chorus) is not a digital signal processor at all. All signal processing is analog. The processor just stores and establishes gain/volume and signal routing settings for various circuits.

The MP-1 can be summarized as:
* Discrete FET input stage followed by a programable attenuation feeding an op-amp buffer with soft diode clipping driving either a tube channel or SS channel
* a four-triode (2 x 12AX87/ECC83) tube board with two FET-switched voicings and a programmable attenuation between the second and third stages.
* solid state channel with NE572 compression chip
* a master volume section shared by both channels feeding into a four-band EQ based around a quad op-amp
* a chorus based on an MN3007 bucket brigade chip, with a NE570 compander around it for noise reduction ("stereo" achieved by inverting the chorused signal into the other channel).
* switchable effects loop after EQ, before chorus.

* all glued together with op-amp buffering running on -15/+15 rails.

Can I use digital glue with analog chips?  winky  :lmao:

A chap I know who built his own Amp had drilled one too many holes on the front panel so he labeled it anyway; 
It says, "Digital Input", and yes it's just big enough to stick your digit finger in the hole.
xP
Phil.

[gbono]

So we have two chip suppliers for most MI DSP applications and it appears that "early" designs date back to the late 1990's.

Analog Devices
Texas Instruments

It also appears that Peavey, Fender, etc used this hardware with different 3rd party developers. I'm going to try and put together a list of "vintage" devices through the most current chip sets. So if anyone has any comments on the earliest chip set part numbers, let me know.