Leslie 147 (ampless) connection options - M3, BCV, DXR-20

[gnawlzchawlz]

I already own an M3 and a BCV. The BCV runs off a DXR-20.

I just purchased an ampless 147RV. It has a receptacle box with four sockets to control speed. Speakers are totally passive and have a single red/black lead that sends sound to both of them.

So, firstly, can I safely drive the 147 with my M3's amp? Better yet, can I hook it up to the DXR-20 easily and safely?

Secondly, lets say I couldn't wait and hooked it up to the M3's speaker leads anyways. Am I straining the amp doing this or risking damage to the speakers?

Lastly, if none of the above options are realistic, what's a good cheap setup to power and connect the Leslie?


Not totally dumb but not too savvy with electronics. I can solder things together with clear instructions. With limits. That's about it. I appreciate any help/feedback!

[peterb_2795]

Assuming that you have a Jensen V21 driver attached to your upper horn, the first thing that you might want to checkout is that your cabinet has a crossover in it. The V21 is not happy at all with frequencies sub 800Hz being pushed at it. However, since you have provided little detail as to what drivers are in the cabinet, it could be that the previous owner has replaced the lot with (say) 8 ohm drivers. A photo would be useful in this case to give ppl a better idea with what you are dealing with.

Also, it would be good to know whether your M3 uses field coil or permanent magnet drivers if you are seeking comment on "connectability" - all of which is not a problem, but again, in the light of little description, photos would assist.

Cheers, P

[gnawlzchawlz]

Thanks P,

Info as follows:

Leslie
-Upper horn = 100W Ferro-fluid Built for Leaslie. Measures 8ohms
-Lower sub = unknown make. 15in. Measures 8ohms
-Crossover = looks original and in tact. Wires leading to the crossover measure 9-10 ohms

M3
-Permanent magnet - 8ohms
-Stock other than organ mate reverb and presets

DXR-20
-Two Jensen A-12 field coil speakers. 12 in I think
-Pre-amp has an "additional amplifier" plug for 5 pin cable.

I would really love to connect the Leslie to my BC and tone cab. Thoughts?


Forgive the dark photos. Working in a tight space.

[tpappano]

What is the serial number of your M3? The DX20 expects to be driven by a “balanced” source. Early M3s have a center tapped speaker output transformer which conveniently provides a balanced output. Later models do not, and would need a small transformer added to make the DX20 happy.

[gnawlzchawlz]

Tom,

I dont want to connect the dxr20 to the M3.
The dxr20 is currently connected/powering my BC. I'd like to add the Leslie to that setup.

If that's too difficult, I'd keep the Leslie on the M3. M3 serial is 149361.

[gnawlzchawlz]

Oops. I see that wasnt very clear in my original post. Anyways, any suggestions are appreciated :-)

[David Anderson]

Are you sure those speaker drivers are 8 Ohms? Remember that 8 Ohms is a speaker's AC impedance, and a speaker's DC resistance, measured by an Ohmmeter, will be lower. A 16 Ohm Leslie woofer can measure as low as 9 Ohms DCR. A horn driver may measure 11. The original crossover is designed for 16 Ohm drivers.

And you do have to unplug the speakers from the crossover to measure -- in case you don't know.

[gnawlzchawlz]

David, I think the sub and driver are actually 16ohm. I misread because they were just measuring low around 9 and 10.

Anyways, to keep things simple, I bought an amp that can be bridged to mono for 16ohms and ordered a custom trek obl line out. The obl will allow me to switch between the leslie and tone cab or play together.

Ive never heard the BC through a Leslie so Im super excited to hear it. The BC's well maintained - came out of a funeral home.
Thanks for the input.