Vibrato/Tremolo

felipemuniz · 14th October 2012, 06:43 PM

I'm finishing this amp here and works pretty well the power amp and the 2 channels (normal and bright) but the other channel, vibrato/tremolo is getting a overdrive on instead a vib/trem effect..

I'm trying to test it with a 12ax7 instead a 12au7 (I dont have a 12au7 here, i bought 2 of them, but left 2 weeks to be delivered)... BUT just for test, I changed the cathode resistor from V3 to 47K instead a 1.5K, and the effect dont worked.. Nothing at all of vibrato or tremelo, nothing..

I wanna be sure that's because I changed the tube... Anyone can help? Perhaps explain to me how this effect channel works..

There's the schematic on attachment.
Thank you for read ^^

Copyrighted material removed by moderation. This schematic was clearly marked as restricted use copyrighted material and may not be posted here. You may post a complete hand drawn version of the schematic or excerpts as preferred. Please read the forum rules!

jazbo8 · 14th October 2012, 10:33 PM

The Valve Wizard- Tremolo Oscillator

Jaz

trobbins · 14th October 2012, 10:43 PM

Do you have LFO output signal from V1a, and at anode/cathode of V1b ?

Why did you choose 47k ?

Do you get acceptable amplified input signal at anode of V1a and V1b ?

kevinkr · 15th October 2012, 04:21 PM

This clearly belongs in the Instruments & Amplifier forum. To wit:

Quote:

Tubes / Valves All about our sweet vacuum tubes

Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

AND

Quote:

Instruments and Amps Everything that makes music, Especially including instrument amps.

14th October 2012, 06:43 PM	#1
felipemuniz diyAudio Member Join Date: Mar 2012	Vibrato/Tremolo I'm finishing this amp here and works pretty well the power amp and the 2 channels (normal and bright) but the other channel, vibrato/tremolo is getting a overdrive on instead a vib/trem effect.. I'm trying to test it with a 12ax7 instead a 12au7 (I dont have a 12au7 here, i bought 2 of them, but left 2 weeks to be delivered)... BUT just for test, I changed the cathode resistor from V3 to 47K instead a 1.5K, and the effect dont worked.. Nothing at all of vibrato or tremelo, nothing.. I wanna be sure that's because I changed the tube... Anyone can help? Perhaps explain to me how this effect channel works.. There's the schematic on attachment. Thank you for read ^^ Copyrighted material removed by moderation. This schematic was clearly marked as restricted use copyrighted material and may not be posted here. You may post a complete hand drawn version of the schematic or excerpts as preferred. Please read the forum rules!

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14th October 2012, 10:33 PM	#2
jazbo8 diyAudio Member Join Date: Jan 2011 Location: In Transient	The Valve Wizard- Tremolo Oscillator Jaz

14th October 2012, 10:43 PM	#3
trobbins diyAudio Member Join Date: Feb 2009 Location: Melbourne, Oz	Do you have LFO output signal from V1a, and at anode/cathode of V1b ? Why did you choose 47k ? Do you get acceptable amplified input signal at anode of V1a and V1b ?