LND150 Tremolo?

[Mr. Lime]

Hi,

I'm currently working out a circuit for a cathode biased EL84 amp and realized I have not one single amp with a tremolo built in.
As the oscillator is not part of the signal I think it's unnecessary to waste a triode for it. There is almost nothing to find about simple LND150 oscillators and I wonder why?

Has someone done this before and can recommend a simple circuit?

Thanks a lot!

[sluckey]

read this...

http://el34world.com/Forum/index.php?topic=24472.0

[xtian]

More excellent reading: http://www.geofex.com/Article_Folders/m ... tfolly.htm

This includes the famous MOSFET B+ reducer that I've used many times.

[pompeiisneaks]

More excellent reading: http://www.geofex.com/Article_Folders/m ... tfolly.htm

This includes the famous MOSFET B+ reducer that I've used many times.

All written up by our very own R.G.

~Phil

[Mr. Lime]

Thanks for the fast reply!

I see, that's quite simple but does require a LDR. I have pedals that do basically the same and I would like to follow a more traditional approach where the tremolo is connected to the cathode of a gain stage for bias wiggle that can't be done with a pedal.

Something like a Vibro Champ or the Kalamazoo Model 2:
http://www.rru.com/~meo/Guitar/Amps/Kal ... 2Schem.gif

[martin manning]

You can do that with an LND150.

[Ten Over]

Is there anything about tremolo in the geofex link?

[statorvane]

I think this is the one you are looking for: http://www.geofex.com/Article_Folders/s ... remolo.htm

[Mr. Lime]

The Vibe Champ SS Vibrato looks good as well but isn't it missing diodes?
Is that circuit verified?



The Supro 1690T has a simple circuit too which could be done with a LND150. Not sure about the Intensity control as variable plate resistor..

Supro 1690T Tremolo.PNG

[martin manning]

The Vibe Champ SS Vibrato looks good as well but isn't it missing diodes?

Why do you say that?

I think you could do a simple LND150 LFO, and couple that in with the cathode of a preamp stage ala the Kalamazoo Model 2 above.

[Mr. Lime]

The Vibe Champ SS Vibrato looks good as well but isn't it missing diodes?

Why do you say that?

I think you could do a simple LND150 LFO, and couple that in with the cathode of a preamp stage ala the Kalamazoo Model 2 above.

Ah, I had the optional protection diodes in mind but they are only useful at large input signals.
You mean something like this?

LND150 Bias Wiggle Tremolo.PNG

I like the simplicity of that circuit but eventually miss a control for intensity.

[Ten Over]

Ah, I had the optional protection diodes in mind but they are only useful at large input signals.
You mean something like this?
LND150 Bias Wiggle Tremolo.PNG

I like the simplicity of that circuit but eventually miss a control for intensity.

The LND150 LFO probably won't oscillate with a bias that high.

[martin manning]

Something like this. You will probably get some noise on the intensity pot, but it is very effective this way, from completely off to very choppy.

[Mr. Lime]

Thank you very much, Martin.

This one indeed looks very simple!

How about cathode bypass caps parallel to R3?
Also I'm thinking about global feedback which had to be fed back to the cathode of that gain stage just like in a Vibro Champ.
You would rather insert the LFO after the cathode resistor?

Here's a reference:

[martin manning]

For that arrangement I would add another FET as a source follower, exactly as in the Vibro-Champ.