Using my hammond's rotary speaker for guitar

[stuisthebest]

Howdy!

my hammond organ has a built-in (NOT FREE-STANDING - NOT SURE IF THIS MAKES A DIFFERENCE) rotary speaker, and i'd like to use it to play guitar through - but still be able to play the organ through it too.

the organ has a mono RCA input so it's quite easy to plug a guitar into that, but the sound is terrible, very boomy, and even with a mixer in the chain with a lot of EQ applied, it sounds nothing like, for example, a fender vibratone (incidentally, if anyone has one of those, give it to me).

1. If i connected a guitar amp directly to the organ's speaker would this improve the tonal quality?

2. if the answer to 1 is yes, i was thinking i could just leave a couple of female connectors (of some type) dangling from the terminals on the back of the speaker, and have corresponding male connectors dangling from both the guitar amp and from the organ, so i could swap between them easily as and when i need by unplugging rather than having to solder. is this possible, and if so, what's the best simple mono connector?

3. i need some help matching the speaker to the correct amp, wattage and resistance-wise. unfortunately i can;t give you much info on it. it's about 7-8 inches and theres a sticker on the enclosure that reads "230V, 50Hz", but that could be referring to the motor for all i know about this stuff.

4. in the event that 2 is possible: i notice that currently one of the two terminals on the back of the speaker has two wires, rather than one, going to it. why is this? i assume if i decided to attach a connector to this i could just keep them both soldered together, if they're going to the same terminal on the speaker anyway.

sorry for the essay. thanks very much in advance

NOTE: over at another forum, someone recommended me the leslie preamp combo pedal. this is out of my price range, plus i can't figure out if it would work on a built-in leslie - i assume it sends commands to switch on/speed up via the 9-pin cable, but would that work going INTO the organ? just curious with that one really, i won't be buying a pedal any time soon.

[Tim_at_Jonas]

Just modify the organ by adding a guitar input. Depending on the model, there may already be one (such as the RCA input on the expression box of the A100/C3/B3).

[Bob411]

Hi. I have an early 70s Hammond, different mode, mine's a Concorde 2107. I too wanted to be able play guitar through the Leslie. My organ has "main speaker" a 15" woofer and a tweeter and the Leslie is a 6" x 9". My organ has two amps, one for the 15" and the other for the Leslie. My RCA plug is non-functioning. I found where to insert a guitar but, it sounded really bad. I did make an effects loop for the main speaker so I can add guitar dirt pedals and it sound great.


Good luck. Sorry I don't know what ohms your Leslie speaker is. If you have an ohm meter, you could unhook wires from speaker and measure the ohms of the speaker. If you find out it will work with your guitar amp, what I would do is get a 1/4" guitar jack "Switchcraft is a good brand" to plug you guitar amp into and a 3 way switch and mount them to the back panel of the organ.

[Papus]

Just get a Mini Vent II.
The wasted labour & time and ultimately disappointment in the internal Leslie isn’t worth the hassle.

[enor]

Just get a Mini Vent II.
The wasted labour & time and ultimately disappointment in the internal Leslie isn’t worth the hassle.

Or indeed, why not get a real Leslie?

[Papus]

Or indeed, why not get a real Leslie?

the mighty dollar, and convenience hahaha
Oh, and you'll have to construct or buy a guitar to Leslie preamp/switcher

[enor]

the mighty dollar, and convenience hahaha
Oh, and you'll have to construct or buy a guitar to Leslie preamp/switcher

Nah, if you want to play guitar through a Leslie, the best thing is to bypass the Leslie amp and feed the crossover from a guitar head.

[Drawbar Dave]

Nah, if you want to play guitar through a Leslie, the best thing is to bypass the Leslie amp and feed the crossover from a guitar head.

Yep what he said

[stuisthebest]

thanks for all the replies so far. indeed, money is the big factor here or i'd just get a vibratone. that's the dream. there is a TC electronic 'vibra clone' pedal for like £35 ($45) which is extremely reasonable but the point of this whole exercise is to keep things analogue and have some fun messing around with wires and watnot. plus how good can a £35 pedal be compared to the real thing?

a very helpful gentleman DM'd me and pointed out that although my plan to use a guitar amp head straight into the leslie's speaker would work, the speaker itself wouldn't be optimised for guitar and may be missing some crucial mids to give me the tone i want.

i've seen a few people on ebay selling the motor and cylinder from a leslie (or whatever brand) that i could use to build my own amp. maybe that's the project i'm looking for.

[picothinker]

I don't think that the Cheesewheels (internal styrofoam Leslies, look kind of like a block of cheese), have a crossover. Many external Leslies are 16 ohms. You cannot directly measure speaker impedance with a voltmeter, even though they both say 'ohms'. A voltmeter is meant to measure DC resistance, and and impedance is a characteristic of AC circuits.

However, you can sort of approximate it. The resistance reading across the terminals should be roughly 15% less than the nominal impedance on the label.For example, it's normal for an 8-ohm speaker to have a resistance between 6 or 7 ohms.Be sure to remove any wires that to to the amp first.

Don't blow it up, it's only perhaps a 6" or 8" speaker, not something you can crank a 100-watt Marshall into.

[clem]

i've seen a few people on ebay selling the motor and cylinder from a leslie (or whatever brand) that i could use to build my own amp. maybe that's the project i'm looking for.

That would be your best bet. Most of those are set up for 10" or 12" speakers so coming up with a decent guitar speaker would be easy. I built one once and used one of those Eminence 12" speakers that had the hole through the magnet and was threaded to accept a horn driver. My plan was for it to be my practice Leslie but I never did use it much.
This is the speaker I used. This pic was with a Piezo. I later swapped it out for a Peavey horn driver.

This is the cabinet I put it in

[enor]

I don't think that the Cheesewheels (internal styrofoam Leslies, look kind of like a block of cheese), have a crossover.

The cheesewheels themselves don't have crossovers, but there are additional crossovers outside of them in the organs that feature them. The bass frequencies are kept out of the cheesewheels.

[jsaxe]

I get the impression from the original post that the Leslie just might be a rotosonic. It would be helpful to know just what model Hammond the OP is referring to. I've used salvaged rotosonics and cheesewheels for guitars, synths and organs. Roto's are kind of disappointing, but easy to hook up. I'm pretty sure that they're 8 ohms - I can confirm that if it's the case, I have one on hand. Cheesewheels are what the old Fender/Leslie Vibratone cabinets had.

[Bob411]

I get the impression from the original post that the Leslie just might be a rotosonic. It would be helpful to know just what model Hammond the OP is referring to. I've used salvaged rotosonics and cheesewheels for guitars, synths and organs. Roto's are kind of disappointing, but easy to hook up. I'm pretty sure that they're 8 ohms - I can confirm that if it's the case, I have one on hand. Cheesewheels are what the old Fender/Leslie Vibratone cabinets had.

OP started another thread about possible asbestos https://www.organforum.com/forums/sh...-hammond-organ . Unless he is asking about two different organs...

Hello there :)

opened up a model 7122J (1973?) to take a look at the rotary speaker and discovered some acoustic insulation on the back of the speaker - just want to check if it could contain asbestos? pictures:

https://ibb.co/cxV4QU
https://ibb.co/dPE65U
https://ibb.co/eOozQU
https://ibb.co/jzGxC9

what would be the best way to test if it is or isnt? someone on gearslutz suggested holding a single strand over a flame, and that asbestos will not melt whereas fiber glass will - is this true?

thanks in advance for any help!

[stuisthebest]

I get the impression from the original post that the Leslie just might be a rotosonic. It would be helpful to know just what model Hammond the OP is referring to. I've used salvaged rotosonics and cheesewheels for guitars, synths and organs. Roto's are kind of disappointing, but easy to hook up. I'm pretty sure that they're 8 ohms - I can confirm that if it's the case, I have one on hand. Cheesewheels are what the old Fender/Leslie Vibratone cabinets had.

correct, not a full Leslie brand with horn/drum, just a cheesewheel. still, as you point out, it was good enough for the vibratone!

OP started another thread about possible asbestos https://www.organforum.com/forums/sh...-hammond-organ . Unless he is asking about two different organs...

yes same organ!

since all i need is a working cheesewheel/motor combo to build my own from a spare guitar amp, seems like that'd be a fun project. i'll probably still give hooking up an amp head directly to the speaker a go anyway.