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DIY Stompboxes => Building your own stompbox => Topic started by: majornoob on January 26, 2011, 12:35:13 AM

Title: true bypass with tube pedals
Post by: majornoob on January 26, 2011, 12:35:13 AM
Hi!
I have been working on the stak-in-a-box from Paia that I built when I was just starting. I decided that I wanted to move it into a new box and true bypass it.
I just was thinking about the pedal and realized that I want to keep the tube warm all the time, at least I think.
So is there a different type of bypass I should be using? Sorry if this has already been answered but I have searched around and couldn't find anything.
Thanks for the help!

the schematic is at this site http://www.paia.com/proddetail.asp?prod=9210K&cat=14
Title: Re: true bypass with tube pedals
Post by: Mike Burgundy on January 26, 2011, 04:47:18 AM
This is "just another circuit" and should recieve the same treatment. Search on bypass and read the technology of bypass article at http://www.geofex.com/ and you're good. A switching scheme that ground the input is a good idea for high-gain circuits.
Leave the circuit always on when in use, even in bypass, or else you will get an awful thump every time you switch it on.
Title: Re: true bypass with tube pedals
Post by: Ice-9 on January 26, 2011, 05:51:45 AM
Converting the pedal to true bypass won't turn off the valve heaters. If you did wire it up to turn off power to the effect then it would be unusable, as everytime you stomped on the switch it would take about 10seconds for the effect to start working and popping (the valve would need to heat up).

As suggested above read up on true bypass and all will be obvious, treat it like any other true bypass wiring and include a pulldown 1M resistor and your good to go
Title: Re: true bypass with tube pedals
Post by: wavley on January 26, 2011, 09:27:10 AM
Didn't Puretube explain his relay bypass that he designed for the EHX tube pedals somewhere on this board?  You might try searching his posts for that.
Title: Re: true bypass with tube pedals
Post by: petemoore on January 26, 2011, 11:54:17 AM
  still in the small signal/line boost power range.
  When the power amplifier output is involved..and large power, I can't say switching isn't possible, but can say hardwiring certainly has it's advantages.
Title: Re: true bypass with tube pedals
Post by: PRR on January 26, 2011, 09:22:54 PM
"True Bypass" normally leaves the EFFECT powered-up all the time. Just signal and maybe an LED is (dis-)connected.

Otherwise you'd get a start-up THUMP when you went into your glorious solo.

Tubes are different only because you'd be silent for 10 seconds before thump and effect, and because leaving a 300mA heater going is more drain than a 1mA-10mA transistor. However since you'll surely use wall-power, battery-drain is not an issue, and the electric bill ($0.000,5 per hour) hardly impacts your total playing costs (strings, shirts, etc).