Fifth Workshop Bulletin added to Piet's EchoTapper Blog

Anything to do with eTap2HW

Moderators: David Martin, dave robinson, Iain Purdon, George Geddes

Fifth Workshop Bulletin added to Piet's EchoTapper Blog

Postby scmitche » Thu Aug 29, 2013 2:24 pm

I have written a further Workshop Bulletin 5: Improving FET Gain and Lowering White Noise eTap2hw, this fits with the previous 4 bulletins that I assembled, which are on Piet's Blog at http://www.echotapper.nl/wp.

This workaround shows how to improve FET gain, lower bandwidth from 20kHz to a more electric guitar friendly 10.6KHz and significantly reduce output noise.

Number 1 covers improving the positive headroom of the input operational amplifiers section to align with some of the previous suggestions of ChrisG.
Number 2 is a flowchart type procedure for optimising the FETs by changing the bias resistors. Especially useful for those who feel the need to have a sound which can vary from clean to one rich in harmonics. Also of use to those who haven't measured (or can't be bothered to measure) the FET parameters or perhaps can't measure them because the FETs are soldered into the board.
Number 3 is an inductor/capacitor power supply filter to prevent noise being injected into the eTap2hw by the Arduino automation controller.
Number 4 is a design based on Charlie Hall's Cutting Edge Filter and includes a Frequency Response graph and suggestions on how to use it.

Thanks to all my collaborator's for their inputs to the bulletins; Piet Verbruggen, Philip Hawthorne, Johan Forrer and ChrisG.

Further developments will be posted in the same way so keep looking.

Hope you find them useful,

Steve Mitchell
Last edited by scmitche on Thu Dec 19, 2013 8:35 pm, edited 4 times in total.
scmitche
 
Posts: 47
Joined: Wed Feb 27, 2013 12:03 am
Location: Keighley, West Yorkshire
Full Real Name: Steve Mitchell

Re: Workshop Bulletins added to Piet's EchoTapper Blog

Postby GuitarPhil » Thu Aug 29, 2013 8:38 pm

Cheers Steve, good work.

Here's an active link to Piet's blog http://www.echotapper.nl/wp

Phil.

PS You can use the URL button on the toolbar to insert working links
User avatar
GuitarPhil
 
Posts: 265
Joined: Tue May 11, 2010 11:32 pm
Location: Northern Ireland
Full Real Name: Philip Hawthorne

Re: Workshop Bulletins added to Piet's EchoTapper Blog

Postby des mcneill » Fri Aug 30, 2013 3:58 pm

Hi Steve,
Thanks for your helpful bulletins and the other help you have given me. Your help in optimizing the FETS is certainly worthwhile as I have found and I have now modified three of the five etaps I built, all successfully and to the delight of their owners.

Des.
des mcneill
 
Posts: 324
Joined: Thu Sep 17, 2009 1:30 am
Full Real Name: des mcneill


Return to eTap2HW Forum

Who is online

Users browsing this forum: No registered users and 11 guests

Ads by Google
These advertisements are selected and placed by Google to assist with the cost of site maintenance.
ShadowMusic is not responsible for the content of external advertisements.