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I've been thinking about building a unit without any pre-amping at all, no valves or Fets.
You would 'voice' the guitar with your usual pedal/amp speaker/amp emulations.
It would be a unit with automation. LCD display etc. as per Piet, Johann, Philip and Steven's designs.
I've been thinking about making it as a foot pedal like the Magicstomp. Not exactly like the Magicstomp box, that's diecast but a floor mounted unit.
What do you think ?
It would bring the cost down .
I've tried the bare etap out with my little Korg Ampworks direct in and it works fine.
Cheers,
Ec

What sort of price are you talking Ecca.

Hi Ecca,
The problem I can see is that it would depend exactly how you were going to use the SKRM echo board. It's only 10k input impedance plus it has clock bypass filter capacitors in each input channel so would ruin the pickup's resonant frequency response unless a high impedance pedal or circuit was placed before it.
I have a simulator program running in Texas Instruments TINA that I wrote to help me select replacement pickups for my Burns Marquee and it shows a horrible effect if a guitar pickup is plugged directly into the SKRM. The effect is similar to using a guitar cable more than 50 feet in length.
The SKRM board was designed originally to provide up to 8 effects for a guitar amplifier but expected a high impedance buffer to be provided between guitar and the SKRM input.
This is the very reason that Piet provided the FET in the first place.

Hope this is helpful.

Steve Mitchell

Ecca,

You'd definitely need another pedal of some sort in front of the SKRM as a buffer/preamp as it isn't designed to accept a guitar direct. The trouble then would be,it would sound different depending in what pedal people used in front of it.

Phil.

I never had any intent to put the guitar straight into the FV1 module.

You would 'voice' the guitar with your usual pedal/amp speaker/amp emulations.

is what I said........

Hi Ecca,
OK so that's defined the echo positioning in your chain.
EDIT!!: Sorry I read the input resistors incorrectly from the schematic (old age eyesight again) the actual paralleled left and right input impedance at 1kHz will be ~22.5k so will be OK for Boss pedals and the like.

The eTap2HW floor pedal produced by Mick Taylor has high impedance buffers but does not yet have a FET stage but watch out for some fairly dramatic developments on the FET front in the near future.

You are lucky to have a Korg Ampworks as they are a good unit and now out of production. My observations using a Korg AX3000G multi-effect (similar software to Vox Tonelab but missing the 12AX7 driven, power amp simulator stage) are that my carefully optimised FET eTap2HW automation adds a lot of warmth and character to the Korg amp models and cabinets when playing through the PA system. The effect is so noticeable that I have a "null echo" patch, which I use instead of a bypass to keep this FET warmth even when not using the eTap2HW echo patches. The eTap2HW is of course used in the normal 1st in chain position. This sound shaping of the common source FET preamp (often referred to as the Tillman pre-amp in guitar circles) is why it has proved so popular in various guises over the last 10+ years.

Regards,
Steve