As it turns out, the "buyer" never showed back up. It really seemed like a dumb idea.

Thank you!

开云体育

Organs that Hammond recommended the 710 for, include, T-500, the higher spec Dolphin 9000 series models, the Phoenix, the Cougar, the Maverick, 8000 series Auroras, and the Concorde. This list may not be exhaustive, basically, any mid to late 70's organ that has a built in Leslie and a 9-pin socket. By the time we got to the 80's, the successors to these models had 11 pin Leslie sockets.

I'm familiar with using the trek II xover to connect a 710 to a single channel Hammond and in fact have one of those now. My question is what organs, Hammond or otherwise, does a stock 710 connect to directly? I can't seem to find anything online except for the convertion.
Thanks

I'm familiar with using the trek II xover to connect a 710 to a single channel Hammond and in fact have one of those now. My question is what organs, Hammond or otherwise, does a stock 710 connect to directly? I can't seem to find anything online except for the convertion.
Thanks

开云体育

Not really, you may be able to hear mechanical noise inside it using a stethoscope. The old mechanic's trick of using a long screwdriver and holding the tip against the scanner casing and putting your ear on the handle would do. Unless you know what a healthy scanner sounds like though, it would be difficult to draw a conclusion.

I've been thinking about the chorus issue, and looking at the schematic. Normally one side of the vibrato line is grounded through a switch contact in the vibrato selector switch. In chorus positions of the switch, it's open, and the ground is through a resistor. If there was a short across the input of the vibrato line, this would give exactly the symptoms you describe. Could either be a short between terminals 1 & 2 of the line, or the first capacitor in the line shorted. If one of the later capacitors was shorted, this would cause "choppy" vibrato.

Thank you Chris and Scott,

Follow up question;

Is there a way to determine the if scanner is or is not turning before removing and disassembling it?

On Fri, Aug 7, 2020 at 11:24, Scott Hawthorn

<organfreak@...> wrote:

AND.... The symptom of having a half-strength signal when Vibrato Chorus is engaged verifies that the non-vibrato signal is working, since it is mixed-in with the vibrato signal in that mode. But, my question is, which channel amplifies that non-vibrato signal while in chorus mode? If it's the vibrato amp, that means it is working after all and the scanner is stuck.

On 8/6/2020 11:47 PM, Chris Clifton wrote:

Probably not the scanner. A stuck scanner would still allow signal through the vibrato system, just without vibrato effect. A common fault that I've found with the vibrato and non-vibrato pre-amp sections of the AO-28 is open circuit resistors around the 6AU6 tubes. This will cause low, or no, volume through the affected channel. Most commonly, the anode or suppressor grid resistors are the ones affected.

On 07/08/2020 02:26, john alluneedtoknow via groups.io wrote:

Sirs;

My friend picked up a beautiful C3 from an estate sale. The generator was pretty tight but with oil and time it's running perfectly. The only issue now is the vibrato doesnt work. When switched on the volume drops to near zero, with the knob set to a chorus setting it produces roughly half volume but no effect. With any vibrato setting selected there is no sound at all. We swapped tubes for known good ones with no change. Could this be the scanner?

Thank You to all once again,

?John

--

Virus-free.

Thank you Chris and Scott,

开云体育

AND.... The symptom of having a half-strength signal when Vibrato Chorus is engaged verifies that the non-vibrato signal is working, since it is mixed-in with the vibrato signal in that mode. But, my question is, which channel amplifies that non-vibrato signal while in chorus mode? If it's the vibrato amp, that means it is working after all and the scanner is stuck.

开云体育

Probably not the scanner. A stuck scanner would still allow signal through the vibrato system, just without vibrato effect. A common fault that I've found with the vibrato and non-vibrato pre-amp sections of the AO-28 is open circuit resistors around the 6AU6 tubes. This will cause low, or no, volume through the affected channel. Most commonly, the anode or suppressor grid resistors are the ones affected.

Sirs;

My friend picked up a beautiful C3 from an estate sale. The generator was pretty tight but with oil and time it's running perfectly. The only issue now is the vibrato doesnt work. When switched on the volume drops to near zero, with the knob set to a chorus setting it produces roughly half volume but no effect. With any vibrato setting selected there is no sound at all. We swapped tubes for known good ones with no change. Could this be the scanner?

Thank You to all once again,

?John

Sirs;

开云体育

开云体育

Even before you turn the rotors on, a Leslie is far from Hi-Fi. Treble roll off starting at a few KHz, an amplifier with rather higher distortion levels than usually acceptable for hi-Fi. Then when you turn the rotors on! Slow would sound like a turntable with a slipping belt, fast, like a tape deck with a bent capstan. The one thing that a Leslie cabinet may beat most Hi-Fi speakers on is bass, that 15" speaker in a big cabinet can shift air with the best of them. Used as stationary cabinets with the motors switched off, and driven by the Crown amps, a Leslie probably wouldn't sound all that bad. It wouldn't sound particularly good either, especially in terms of treble response, cymbals and similar instruments would loose a lot of their impact.

At the end of the day, it's his money, and if you've got no use for the Leslies, let him have them if he wants.

I sold a fellow some PA cabs out of my warehouse and he saw that I had a few Leslie cabinets. He became rather excited and said he’d been looking for one to use as the center channel in his home stereo setup. He said his system currently uses Klipsch La Scalla’s and Cornwall’s driven by Crown DC-300’s so on some level he knows what he’s doing.
He asked me if I thought it would work and I explained (Nicely) that I didn’t think it would be a good idea, but he seemed convinced and says he intends to return over the weekend to pick one up.
Does anybody have any experience using aa Leslie in this way? Perhaps it’s just something I’m unaware of but sure seems like a bad idea to me.

I sold a fellow some PA cabs out of my warehouse and he saw that I had a few Leslie cabinets. He became rather excited and said he’d been looking for one to use as the center channel in his home stereo setup. He said his system currently uses Klipsch La Scalla’s and Cornwall’s driven by Crown DC-300’s so on some level he knows what he’s doing.
He asked me if I thought it would work and I explained (Nicely) that I didn’t think it would be a good idea, but he seemed convinced and says he intends to return over the weekend to pick one up.
Does anybody have any experience using aa Leslie in this way? Perhaps it’s just something I’m unaware of but sure seems like a bad idea to me.

开云体育

Open or low value C26 would certainly reduce gain of the stage. I've seen treble boost circuits in guitar amps that work by disconnecting a large electrolytic cathode bypass capacitor leaving a much smaller capacitor to effectively bypass the cathode resistor only at higher frequencies. Thus reducing the gain at low frequency due to the resulting negative feedback at the cathode.

I would have expected a fault in the AO-28 to also cause distortion through the 122 playing the same chords at the same swell pedal opening. It might be interesting to turn the volume control on the 122 down so that you can play with the swell wide open without annoying the neighbours. If you get the same distortion through a "throttled back" Leslie, then the problem is very likely to be in the AO-28.

Hi Chris,

Thanks for replying to my request for help.

The distortion occurs long before the Burn clipping indicator comes on.

What I realize is the the lower range is where most of the distortion is.?

I think my problem is in the AO-28 preamp not the Burn Leslie Sim or the pad circuit.

I had been playing single notes to test ...The lower range is always distorted and at a very low volume compared to the higher octaves. When I play chords in the upper range the distortion shows there too, but much more volume.

I am trying figure out whats going on. I'll measure the AC voltage between G and G should be 3 to 4 volts.

I was reading on Bentons Site that if C26 in the AO-28 is open? it will cause an attenuated lower range.

John in Brooklyn

开云体育

The variable line out circuit is exactly what you would find on Hammond Wiki, it should be possible to control the output level to suit the input of almost any amplifier, mixer desk, or effects box.

I've just had a look at the Crumar manual online. If you've set the input level according to the instructions, so that the clip light isn't lighting, then the sound through the Crumar Burn shouldn't be distorted.? If you can't get loud enough without turning the input up to the point where the clip light comes on, you need to look further along the amplifier chain. What amplifier are you using? If the amplifier isn't capable of producing your required volume, no amount of fiddling with the input to the Burn will help. Try connecting your line out directly to the amplifier, and see what results you get then.

My guess is that either, you are overdriving the input of the amplifier used, quite likely if it's a guitar type amplifier. Or, the input of the amplifier being used isn't sensitive enough, and you're overdriving the Burn in an attempt to get enough drive. This may possibly be the case if you're using a line in input on a Hi-Fi type amplifier.

Hi Everyone,

I have a Crumar burn Leslie simulator I play with my B3, so that I dont have to use the 122. My apartment is small and the 122 draws complaints.

I built the circuit shown in the Crumar Burn Manual. It's just a 1k resistor, a 1 microfarad cap, and 1 100k pot all? in series to ground. the output is of the wiper of the 100k pot, so the level is adjustable.
I connected the "1k resisitor end of my circuit to one of the "G" terminals on my B3 (AO-28 pre amp).

When I try to adjust the pot in the circuit above the sound coming out of my Burn Leslie sim can't get loud enough without being distorted. I have the distortion effect turned off on the leslie sim.

ok here are my questions:

1.Is this circuit??I am using correct ?? I see other "line out" circuits at "


2. I think the two G terminals on the AO-28 are a differential pair. Why wouldn't we want a balanced signal? "differential pair" from both the G terminals?...? ?I am thinking of putting together a? circuit similar to what I have but with ganged pot so that I can control a balanced output taken off the two G terminals. I see the?the Art Tube MP. It is an inexpensive tube preamp that also works as a direct box.?I could put the Art Tube Pre MP between the Balanced line pad circuit and the Burn Leslie sim.

any ideas or comments would be appreciated.
John in Brooklyn

Hi Everyone,

I have a Crumar burn Leslie simulator I play with my B3, so that I dont have to use the 122. My apartment is small and the 122 draws complaints.

I built the circuit shown in the Crumar Burn Manual. It's just a 1k resistor, a 1 microfarad cap, and 1 100k pot all? in series to ground. the output is of the wiper of the 100k pot, so the level is adjustable.
I connected the "1k resisitor end of my circuit to one of the "G" terminals on my B3 (AO-28 pre amp).

When I try to adjust the pot in the circuit above the sound coming out of my Burn Leslie sim can't get loud enough without being distorted. I have the distortion effect turned off on the leslie sim.

ok here are my questions:

1.Is this circuit??I am using correct ?? I see other "line out" circuits at "


2. I think the two G terminals on the AO-28 are a differential pair. Why wouldn't we want a balanced signal? "differential pair" from both the G terminals?...? ?I am thinking of putting together a? circuit similar to what I have but with ganged pot so that I can control a balanced output taken off the two G terminals. I see the?the Art Tube MP. It is an inexpensive tube preamp that also works as a direct box.?I could put the Art Tube Pre MP between the Balanced line pad circuit and the Burn Leslie sim.

any ideas or comments would be appreciated.
John in Brooklyn

开云体育

There is usually a capacitor across the tremolo switch contacts in the connector box in the organ, and one across the relay coil in the Leslie. Maybe worth checking the capacitors across the relay contacts as well, I've frequently seen these fail, usually short circuit causing one motor set or the other to be permanently on, but an open circuit capacitor could cause the symptoms described.

I'd recommend using X2 rated capacitors for these mains voltage applications. As well as being far less likely to fail due to the stress of absorbing the switching spikes that cause interference, they are designed to fail safe and go open circuit should an internal fault develop. Standard capacitors, even those that have DC voltage ratings several times the mains AC voltage don't always stand up to this suppresion duty very well.

Thanks Scott. I'm getting to old to remember what I did 30 plus years ago. That does make sense.?

开云体育

Thanks Scott. I'm getting to old to remember what I did 30 plus years ago. That does make sense.?

Me too, but I DO remember what I did 60 years ago.

Thanks Scott. I'm getting to old to remember what I did 30 plus years ago. That does make sense.?