Inexpensive preamp to feed my Leslie 147

[bjosko]

Hi

I would love to try my DMC-122/Gemini on my 147.

I already have a Frankenstein box made that handle power and speedswitch that i have used on my old Nord C1, but the C1 have an hot output.

So I need a kind of preamp to bring up the level from the Gemini, and if possible, I will avoid a traditional Preamp pedal like Hammond or Trek.

 

I have a sick dream later on to use the Gemini through a Behringer X-air something, and program some midi switching so I can route organ to the Leslie if I am using Organ only, and the rest of the sounds to my Spacestation/FOH when using other sounds.

 

First of all, I would like to hear how the VB3 are sounding through my Leslie.

[Baldwin Funster]

Art studio MP. About 30 or 40 bucks. Has a preamp tube. Lots of people praise them.

[OB Dave]

I don't think the ART will do the trick. The 147 amp needs to be driven by something with a super low output impedance, otherwise it'll hum like crazy. Besides, the ART box preamp tube is just a starved plate noisemaker. Why bother with that, when you have an actual tube amp in the Leslie?

 

I've never tried it, but you might be able to DIY / roll your own by finding a very low wattage amplifier (maybe 5 watts), driving an 8-16 ohm dummy load in parallel with the 147's audio inputs.

[bjosko]

Sounds complicated... So better with a stock PreAmp pedal ( but I am addicted to half moon switch, and since the Leslie already have a TrekII Eis controller, Leslie stop are an option).

 

So, as a start, I might try to run a cable into the phono plug in the dog house on my A100 ?

I think I have tried that many years ago on another clone, but the outcome was not that great, as I remember.

[OB Dave]

Duh. I forgot something. The 147 amp already has a load resistor in it, because it was designed to either go across the speaker of a spinet/A100 hammond, or run with the speaker disconnected. Tube amps do not like to run without a speaker load, so there's dummy load resistors inside the 147 amp.

 

So find a small guitar amp, like a little practice amp. You don't want a lot of power here. Less is more. Connect the output of the amp to the Leslie audio input pins 1 (ground) and pin 6 (signal). Set the Leslie 147 amps console load resistor to whatever the amp is expecting to see (probably 8 ohms, but possibly 16 ohms if it's am old tube amp). Run the guitar amp at a very low volume at first.

 

This should work but don't call me if you burn your house down.

[Doerfler]

Hey Dave, your phone is ringing.

[OB Dave]

No it's not!

 

[video:youtube]https://www.youtube.com/watch?v=5gw6cR_XTYg

[DanL]

Why not just run into a mixer to boost the signal, then into your custom box?

[JWhllr]

I recently borrowed a Presonus TubePre V2 to play around with a tube preamp to add a tube pre section between my Nord C2D and my Leslie 142. Running the line out of the Nord, rather than the high voltage. Results were underwhelming, but then I tried it out with the EP sounds on my Nord Stage Ex. Very tasty on slow... totally naff on fast.

 

Moral of the story - running out of a line level out into the TubePre, into my own funky little connector box (aren't they great!) and then into my 122 amp worked a charm.

I believe the ART preamp is a similar kind of thing.

 

Edit: I'm assuming your funky connector box takes jack and power in and 6 pin and speed switch jack out.