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DIY Stompboxes => Building your own stompbox => Topic started by: Alpha579 on May 31, 2004, 01:28:58 AM

Title: Tube Rectification Squash Simulation?
Post by: Alpha579 on May 31, 2004, 01:28:58 AM
With all these Jfet circuits from runoffgroove now, i was wondering if you could simulate a tube rectified circuit. Is there a way to accurately do this? Just thought it might be a good idea...
Alex
Title: Tube Rectification Squash Simulation?
Post by: Johnny G on May 31, 2004, 04:16:51 AM
i have heard that in amps that have diode rectification you can put a 100 Ohm resistor in series with each of the diodes to give a sag when playing hard. it basically just means that when the current being supplied increases there is an increased voltage drop across the resistors.

hope thats helpful
Title: k
Post by: petemoore on May 31, 2004, 10:11:55 AM
I just wrote something like this in another thread.
 I read an ad about a transistor rectifier, that plugs into a GZ34 socket, and is so workalike', that the only purported difference is that the GZ34 wears out....the plug in rectifier effectively mimics the GZ34's soft power on, or for a harder, louder [more attackey] sound a regular transistor rectifier can be used to slam on the tube...
 ...might be something cool in this for small signal, or low voltage tube designs also...
Title: Tube Rectification Squash Simulation?
Post by: Alpha579 on June 01, 2004, 12:27:18 AM
Johnny G, do u think you could put a small resistor in series with the battery in overdrive pedal circuirts for the same effect?
Title: Tube Rectification Squash Simulation?
Post by: Prive on June 01, 2004, 01:53:55 AM
Look at the Joe Gagan's designs, almost all of them have a pot in the battery leg.

Saludos, Marcelo.
Title: Tube Rectification Squash Simulation?
Post by: Johnny G on June 01, 2004, 02:27:30 AM
Alpha, you could do that but the reason it works in a tube amp with solid state rectifiers is because the current requirements increase the harder you play (if you have a class AB power amp in it)

in a stomp box with transistors and/or opamps i dont think you get that increase in current draw however hard you play. i suppose you could rig up some sort of circuit with an envelope detector that linked up to a jfet in the battery line and increased its effective resistance the harder you played. im not too sure on that tho, better ask someone who knows what they're talking about

btw prive, i think that those resistors will be there in combination with an electrolytic capacitor to ground to make the power supply filtering a bit more effective

JG
Title: Tube Rectification Squash Simulation?
Post by: Alpha579 on June 01, 2004, 05:11:36 AM
Johnny, whats the simplest way to make an envelope sensor?
Title: Tube Rectification Squash Simulation?
Post by: Prive on June 02, 2004, 05:43:05 AM
Quote from: Johnny GAlpha,
btw prive, i think that those resistors will be there in combination with an electrolytic capacitor to ground to make the power supply filtering a bit more effective

JG

No, i don't talk about this resistors, there is a pot in the batt leg in the Skyripper, and it's to simulate the low batt effect, it makes the pedal behavior more impredectible and fun.

Saludos, Marcelo.