Leslie 251

[jewishjay]

Hi everyone, my friend has an old Leslie 251 that I want to set up for guitar. It worked 5 years ago but he didnt keep the organ, so I think some of the speed control parts are gone. Here is the schematic as it sits, and what I am considering. Too drastic? Sacrilegious? I'm not sure I drew that LTP right, and I've never seen cathodes connected to the OT secondaries like that. Let me know your thoughts, and also....I'd like to add a line level input for re-amping....where and how?

[sluckey]

Your stripped down schematic will not work. No path to ground for the output tubes. The cathode connection to the OT secondary is for negative feedback. Note the OT secondary center tap is grounded. Don't mess with that.

[jewishjay]

Your stripped down schematic will not work. No path to ground for the output tubes. The cathode connection to the OT secondary is for negative feedback. Note the OT secondary center tap is grounded. Don't mess with that.

Sorry for the poor quality pics. Do you mean the .005 caps to ground? I don't think I changed anytning on the secondary side, except elevating the heater artificial CT. Is that part ok?

[sluckey]

I should have said the grids have no dc path to ground.

[jewishjay]

I should have said the grids have no dc path to ground.

Ah, ok, thanks. So 220k to ground between the coupling cap and the input resistor?

[sluckey]

The original PI is a paraphase inverter, not a LTP. If you intend to convert to LTP, then yes, use two 220K grid resistors. If you intend to stay with the paraphase inverter, notice there are three resistors in the grid circuit. Copy those exactly.

[jewishjay]

Thanks for your help. Now, what is the function of the caps to ground where the plates go into the OT? HF roll off, or something more?

[sluckey]

HF roll off. You probably don't want those for guitar.

[jewishjay]

Awesome, thanks again. So like I said in the original post, I want to add a line level xlr input also. How and where would you wire that?

[sluckey]

Connect to the left side of the input cap for the LTP.

[jewishjay]

Connect to the left side of the input cap for the LTP.

Sorry, I don't quite understand. I need a little more explanation about how to add a 10k line level input for re-amping pre-recorded signals. The line in and the guitar in would never be used at the same time, so switching or shunting somehow maybe too.

[jewishjay]

Ok, here's what I'm thinking now, after what you've shared so far. I broke it into 2 images, so it might be a little clearer? How does this look to everyone?

[sluckey]

.

[scstill]

Hi everyone, my friend has an old Leslie 251 that I want to set up for guitar. It worked 5 years ago but he didnt keep the organ, so I think some of the speed control parts are gone. Here is the schematic as it sits, and what I am considering. Too drastic? Sacrilegious? I'm not sure I drew that LTP right, and I've never seen cathodes connected to the OT secondaries like that. Let me know your thoughts, and also....I'd like to add a line level input for re-amping....where and how?

Here is my just finished Leslie 25 into Guitar amp
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