Sluckey’s M-2 Magnatone

[Jhj]

I’d like to build this one. Of course, I need a pair of varistors. A couple sellers are on eBay.

I’ve successfully built Fenders harmonic tremolo, bias wiggle and the “roach” driven. The goal is to have a sample of each type.

Are the sources on eBay, legit? Ready to buy as I write this.

[sluckey]

I bought mine from warbler_muse on eBay.

[scstill]

What do the varistors do?

BTW - because of this thread I discovered the 6gw8 tube. Have been thinking of a project with 6au8 but the GW has 3times the power dissipation. So need to decide if I want a loud amp or a sort of loud amp.

Also I found the AO39 amp on SluckeyAmp site during this search. I have that chassis and thinking the Marshall 18 design might be the way for me to go. I originally bought the AO39 to use the 6AU8 in the style of the M2. But now I might keep the AO39 power amp as is and add a guitar PreAmp

BTW2 - You should add the Supro 1696TN schematic and layout to your site. It was good for my project which I am still working here and there.

[scstill]

to the original ebay legit sellers question,
I buy a lot on ebay and don't really worry because ebay and paypal have excellent protection policy.

[Jhj]

I bought mine from warbler_muse on eBay.

Ok, I’ll place an order forthwith. Thanks.

[Jhj]

I bought mine from warbler_muse on eBay.

And….order placed. Thanks.

I’m a tremolo/vibrato enthusiast and truly enjoy a bit of this effect when plugged in and playing.

[Jhj]

What do the varistors do?

BTW - because of this thread I discovered the 6gw8 tube. Have been thinking of a project with 6au8 but the GW has 3times the power dissipation. So need to decide if I want a loud amp or a sort of loud amp.

Also I found the AO39 amp on SluckeyAmp site during this search. I have that chassis and thinking the Marshall 18 design might be the way for me to go. I originally bought the AO39 to use the 6AU8 in the style of the M2. But now I might keep the AO39 power amp as is and add a guitar PreAmp

BTW2 - You should add the Supro 1696TN schematic and layout to your site. It was good for my project which I am still working here and there.

As I understand it, they vary in resistance with current flow. In that amp, this allows controlled frequency modulation of the guitar signal. This produces the true vibrato effect, as opposed to the volume variation of tremolo.

[PRR]

> As I understand it, they vary in resistance with current flow.

With applied voltage.

[Jhj]

> As I understand it, they vary in resistance with current flow.

With applied voltage.

Yes. Current flow resulting from applied voltage.

I’ll learn more as I build this wonderment. Thanks.

[Jhj]

I bought mine from warbler_muse on eBay.

Mr Sluckey, is there any chance you might be acquainted with this fellow, “warbler-muse”?

[sluckey]

I knew him through the magnatone/valco forum. That was back in 2008 when I was restoring my Magnatone M10-A. He was a boutique amp builder. His stuff was top notch. Then I bought a couple varistors from him through eBay in 2015. I never knew him personally. Read this thread for a little info...

     https://el34world.com/Forum/index.php?topic=12793.0

I just noticed his website is gone. I don't understand his current eBay feedback rating. He had a high rating in 2015.

[HotBluePlates]

What do the varistors do?

Whether we bend-pitch in the air with Doppler, or bend-pitch electronically, we need a changing phase-shift of a signal faster & slower relative to a copy of that signal whose phase is unaltered.  "Faster" equates to the pitch bending upward, and "slower" equates to the pitch bending downward.

  - A purely resistive circuit has no phase-difference between Voltage & Current.

  - Capacitors take time to charge up to a voltage, so they can introduce a phase-difference between Voltage & Current; Voltage is delayed.

  - We can then make a circuit to create phase-shift using R & C.

  - But we need the shift to be changing to get faux-Doppler in an electronic circuit; a static shift from fixed-values of R and C won't create pitch-bending.  We can get there if we can vary-C or vary-R.

  - Variable capacitors can be tricky & expensive.  In the old days it was easier to arrange for variable R.
  - This is where the "variable-resistor" or "var-istor" comes in: its resistance is constant if applied voltage is constant, but its resistance changes if the applied voltage changes.

  - Magnatone's approach was to use R-C circuits to shift phase, but swap varistors in for the "R" element so that the amount of phase-shift is changing in response to a control voltage.  Vi-ola, you gots pitch-bending vibrato.

[Jhj]

I knew him through the magnatone/valco forum. That was back in 2008 when I was restoring my Magnatone M10-A. He was a boutique amp builder. His stuff was top notch. Then I bought a couple varistors from him through eBay in 2015. I never knew him personally. Read this thread for a little info...

     https://el34world.com/Forum/index.php?topic=12793.0

I just noticed his website is gone. I don't understand his current eBay feedback rating. He had a high rating in 2015.

yeah, he’s not responding.

While very rare, this has happened to me one other time in my 20+ years on eBay. In that case, the seller actually passed away but the family had no idea how to deal with the eBay listings. I ended up losing 50 bucks but I didn’t kick about it. The family lost far more.

I suspect a similar circumstance. Health issues. Something. I have to wait until the 11th before eBay steps in. I hope he’s ok.

[Jhj]

What do the varistors do?

Whether we bend-pitch in the air with Doppler, or bend-pitch electronically, we need a changing phase-shift of a signal faster & slower relative to a copy of that signal whose phase is unaltered.  "Faster" equates to the pitch bending upward, and "slower" equates to the pitch bending downward.

  - A purely resistive circuit has no phase-difference between Voltage & Current.

  - Capacitors take time to charge up to a voltage, so they can introduce a phase-difference between Voltage & Current; Voltage is delayed.

  - We can then make a circuit to create phase-shift using R & C.

  - But we need the shift to be changing to get faux-Doppler in an electronic circuit; a static shift from fixed-values of R and C won't create pitch-bending.  We can get there if we can vary-C or vary-R.

  - Variable capacitors can be tricky & expensive.  In the old days it was easier to arrange for variable R.
  - This is where the "variable-resistor" or "var-istor" comes in: its resistance is constant if applied voltage is constant, but its resistance changes if the applied voltage changes.

  - Magnate's approach was to use R-C circuits to shift phase, but swap varistors in for the "R" element so that the amount of phase-shift is changing in response to a control voltage.  Vi-ola, you gots pitch-bending vibrato.

thanks very much for that analysis. I really appreciate it and makes perfect sense.