WTB: saturable reactor from Hammond A0-41 or AO-47

[Brinkman]

If anybody has spares or unused units, I’m looking for 4 more for a warbler-related project I am working on.

Best,
Benjamin

[DummyLoad]

https://www.ebay.com/itm/356413110086

30bux OBO - bet he'll take $25

--Pete

[Willabe]

.... I’m looking for 4 more for a warbler-related project I am working on.

What are you building?

How many SR's are going to be in it?

[Brinkman]

.... I’m looking for 4 more for a warbler-related project I am working on.

What are you building?

How many SR's are going to be in it?

18, see schematic for reference. It will be tubes though, not transistors.

[Willabe]

I have a Warbler I built and it sounds very good.

But looking at the schematic you posted, I don't understand how this works?

Those SR's come from a Hammond organ, I think the L series? This is where the Warbler comes from. And each SR coil is driven by it's own triode. Even though each gain stage/phase shift stage has it's own triode gain stage, each stage still loses a little gain. You can see the voltage loses looking at Sluckey's schematic. So 18 stages with only 1 drive gain stage would have a huge total loss by the time the signal gets to the output.

Each coil is 1 phase shift stage, so 3 stages of phase shift total. And it's enough to get a very good sounding pitch shift.

In the schematic you posted there's 18 SR coils in series. But their not being driven separately. The way it's wired up, it looks like it's just 1 giant SR coil being driven by only 1 gain stage?

How is this supposed to get more than 1 stage of phase shift?

If the SR coil circuit worked with only 1 triode to drive more than 1 SR coil, Hammond would have done that to save money. 

Have you heard a sound clip of this build? Can you post the sound clip?

[Willabe]

I'm going to move part of this over to the main build topic section.

[Brinkman]

The measured resistance of the signal winding in both the Hammond SR and Schaller SR is roughly the same, around 40 ohms. The Schaller schematic linked above states the total series resistance as 800 ohms (800/18~=44 ohms each winding) and the Warbler schematic has each signal winding as being 48 ohms.

In the end, the Rotor sound is really just a phaser with 18 all-pass filters and as such they only affect the signal phase. If my understanding is correct, that creates 9 notches in the frequency response when the phase shifted signal is mixed with the dry signal.

The BC109 transistor is fairly high gain, fwiw.

[Willabe]

Brinkman please respond here;

https://el34world.com/Forum/index.php?topic=32727.0

[jjasilli]

Check your PM's.