[sdiy] Analog matrix chip in Boss ES-8 pedal switcher

[eidorian at aladan.net]

How about the coolio 8x16 Zarlink MT8816?  Just throwing part number 
suggestions around, no actual basis for thinking it might be that chip 
:)

Cheers,
A.



On 2016-01-25 10:43, rsdio at audiobanshee.com wrote:
> It's very likely that the ES-8 does not handle all switching in a 
> single chip.
>
> First of all, IN 1 and IN 2 cannot both be active at the same time.
> The diagram shows a simple 2-to-1 switch that is independent of the
> matrix.
>
> The AD8113 has a 60 MHz bandwidth - it's probably way too expensive
> and overqualified for guitar pedal switching, although the $700 ES-8
> might be able to get away with it. Internally, it's implemented as 16
> separate 16-to-1 multiplexor switches, and it would probably be
> cheaper to just use 16 separate chips if you don't need the 60 MHz
> bandwidth.
>
> The ES-8 also has 2 mono mixer units that can alternately be used as
> 1 stereo mixer unit. These mixer inputs and outputs must also be part
> of the matrix.
>
> They probably dedicate a cheaper, audio bandwidth (not video
> bandwidth), 12-to-1 analog mux for each output (9 sends, 2 mixer
> inputs, out 1 left & out 1 right). I count only 11 inputs for each
> destination. Standard 16-to-1 mux chips cost less than two 8-to1 mux
> chips, so they might even waste inputs.
>
> Don't forget that the switching could be handled by reed switches or
> individual FET parts instead of an analog multiplexor chip.
>
> Brian
>
>
> On Jan 24, 2016, at 3:49 PM, Tom Wiltshire <tom at electricdruid.net> 
> wrote:
>> Ok, so that rules out a load of the smaller ones instead then. AD 
>> don't seem to make a 12x12 matrix, so it'd have to be a 16x16, 
>> something like AD8113. But that seems unlikely because I can't see a 
>> commercial product paying for more switch than they need. Perhaps a 
>> different manufacturer? Who makes a 12x12?
>>
>> On 24 Jan 2016, at 22:40, Mikko Helin <maohelin at gmail.com> wrote:
>>
>>> ES-8 has two inputs (and outputs), seven mono sends (and returns), 
>>> one
>>> stereo send (and return) plus single mono (volume) mono send and
>>> return. For that you need at least 12x12 matrix.
>>>
>>> On Mon, Jan 25, 2016 at 12:08 AM, Tom Wiltshire 
>>> <tom at electricdruid.net> wrote:
>>>>
>>>> There's a lot of possibilities…maybe one of these?:
>>>>
>>>> http://www.analog.com/en/products/switches-multiplexers.html
>>>>
>>>> It's only 8 loops, so that probably rules out the biggest 16x16 
>>>> chips.
>>>>
>>>> On 24 Jan 2016, at 19:31, "cheater00 ." <cheater00 at gmail.com> 
>>>> wrote:
>>>>
>>>>> Hey guys,
>>>>> anyone know what chip they might be using here?
>>>>>
>>>>> http://www.bossus.com/products/es-8/
>>>>>
>>>>> What's your guess on the crosstalk between two adjacent channels? 
>>>>> -40 dB?
>>
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