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Funky Pie



Joined: 23/09/04
Posts: 73
Loc: Flintshire, on the edge of now...
Hammond C3 misbehaving
      #902376 - 21/03/11 06:50 AM
I was recently lucky enough to pick up a functioning C3 with 122 Leslie for a very good price. All drawbars and switches work just as they should. However, I have noticed an inconsistency in bass response. There is a marked "jump" in the tone quality - a sudden "bassiness" that kicks in below a certain note. It's sort of like a crossover point for the lower frequencies and the result is a marked increase in volume. I don't think it's a problem with tonewheels as this crossover note changes every time I turn it on and occurs on both manuals. The problem seems to disappear if I turn on the console after leaving it plugged in for half an hour or so which makes me think it might be something to do with capacitors or valves having not warmed up. I've had the organ working beautifully and evenly at full tilt so I know it's not exactly a component malfunction.

I'm a piano player new to all this so I'd appreciate advice from any Hammond aficionados - Mr Robjohns? It is safe to leave the thing on all the time or will this burn out the valves? A friend told me I shouldn't leave it plugged in (even when switched off) as the charge it can build up inside can be quite lethal!

--this was originally posted in the Keyboards forum but I thought I'd repost here. Mods, please move/delete as appropriate.

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As an impeccably dressed sage once said, "all art is quite useless".


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stratman1979



Joined: 20/03/11
Posts: 4
Re: Hammond C3 misbehaving new [Re: Funky Pie]
      #902559 - 21/03/11 07:36 PM
Sounds like a valve issue to me...

Maybe you can get it serviced.. those C3's are awsome with a 122

Was gutted when I had to sell my 145 cab


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
Posts: 22312
Loc: Worcestershire
Re: Hammond C3 misbehaving new [Re: Funky Pie]
      #902561 - 21/03/11 07:58 PM
Quote Funky Pie:

There is a marked "jump" in the tone quality - a sudden "bassiness" that kicks in below a certain note. It's sort of like a crossover point for the lower frequencies and the result is a marked increase in volume.




Are you sure it's not part of the standard bass note wrap-around that happens on both keyboards (but only with the 16ft drawbar). If you run a scale through the bottom octave the pitch jumps up an octave when you hit the B, and continues on down from there. That can affect the perceived weight and volume...

Quote:

I don't think it's a problem with tonewheels as this crossover note changes every time I turn it on and occurs on both manuals.




Ah... if the break point moves then it's not note wrap-around because that's hard wired between the keyboard and tone generator. So the next most likely is some kind of preamp fault causing variable LF gain -- either a dodgy valve or, more likely, dodgy capacitors.

Quote:

It is safe to leave the thing on all the time or will this burn out the valves?




Valves, capacitors and some of the mechanical components have a finite life and will wear out, so leaving it running the whole time isn't the best idea in the world.

Quote:

A friend told me I shouldn't leave it plugged in (even when switched off) as the charge it can build up inside can be quite lethal!




There certainly are lethal voltages inside, and a lot of original Hammonds aren't properly grounded... which doesn't help! But my A100 is plugged in permanently without any problems. I have confidence in it because I have given it a thorough going over and reworked some of the wiring and power supply issues associated with a 50 year old construction and an 80 year old design!

It sounds to me that your C3 needs some TLC from someone familiar with the ways of the Hammond. Hopefully the problem is trivial (most are) but there are lots of possibilities and you need to work through the whole system to track down and resolve the cause.

hugh

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Technical Editor, Sound On Sound


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Dave B



Joined: 03/04/03
Posts: 5692
Loc: Maidenhead
Re: Hammond C3 misbehaving new [Re: Funky Pie]
      #902726 - 22/03/11 01:24 PM
I'd love to comment, but :

a) I don't know diddly squat about the hardware

and

b) you have a C3+122 and I don't. Ergo, on principle, I hate you!!



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Veni, Vidi, Aesculi
(I came, I saw, I conkered)


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Funky Pie



Joined: 23/09/04
Posts: 73
Loc: Flintshire, on the edge of now...
Re: Hammond C3 misbehaving new [Re: Funky Pie]
      #903222 - 24/03/11 01:21 AM
Sorry, Dave B! If it's any consolation, I'm sure you have lots of lovely gear that I want too!

Thank you, Hugh, for your detailed and very helpful post. After having fired the thing up today after leaving it on for about half an hour, I can only conclude that it must be a capacitance issue. When it's fully warmed and charged up, it really sings! Apparently, back in the day, it was used for Sunday service in a little church and has spent most of the rest of its life as a piece of furniture in Cardiff - in other words, hardly ever played.

I'll take it to a technician (or rather bring a technician to it) and see if I can get the capacitor on the preamp replaced. I think the vibrato scanner might need looking at, and God knows when it was last oiled! To be honest, you are probably right and it just needs a good going over. It plays like a dream though. Thanks again!

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As an impeccably dressed sage once said, "all art is quite useless".


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DB111
member


Joined: 22/11/02
Posts: 87
Re: Hammond C3 misbehaving new [Re: Funky Pie]
      #903242 - 24/03/11 08:38 AM
I would not recommend leaving it plugged into the socket.
We had one in our college studio that was left plugged in, and one Friday afternoon there was a strong burned paper smell in the studio.
When we traced it, (by then, the smoke was an obvious clue to the source of the smell!) it was clear that we were only minutes away from a serious fire as a result of a burned out and shorting transformer. If it had happened a couple of hours later there would have been nobody there to prevent the destruction of all the gear (including the Steinway Grand).

I did plan to use the amp to make a valve guitar amp, but it did not survive two house moves. The tonewheel module went into the classroom as a demo.
Cheers
Dave


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
Posts: 22312
Loc: Worcestershire
Re: Hammond C3 misbehaving new [Re: DB111]
      #903313 - 24/03/11 10:44 AM
The top console off-on switch should isolate everything -- all internal (preamps etc) and external (Leslie etc) connected equipment -- including the various mains transformers.

However, what tends to happen is that people add things (like Leslie interface kits) or modify things without really knowing what they are doing... and as a result things don't often then work as they were expecting.

Also, sometimes the switch can become loose and rotate -- stretching and shorting wires -- not good -- and sometimes the old original rubber-coated wiring simply degrades (or gets nibbled at by rodents), again resulting in shorts and fires. And with no mains safety ground, fuses and trips don't always blow quickly enough either!

That's why I strongly advise getting the machine thoroughly checked over and serviced -- to avoid precisely that kind of nasty surprise.

Also, there is exposed metal on the organ... and it really should be safety earthed which is very easy to do without affecting anything from an audio point of view, but it requires a knowledgeable technician.

As I also said earlier, mine stays plugged in to the wall for convenience -- it is played most days -- but I know it is safe and wired correctly, and the mains switch and wiring is in good condition!

Shame the college organ got broken up -- a replacement mains power transformer (or even a complete replacement preamp) is fairly easily available.

Hugh

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Technical Editor, Sound On Sound


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Matt-Scotty



Joined: 20/12/12
Posts: 1
Loc: |South Glamorgan UK
Re: Hammond C3 misbehaving new [Re: DB111]
      #1025342 - 20/12/12 06:37 PM
"Apparently, back in the day, it was used for Sunday service in a little church and has spent most of the rest of its life as a piece of furniture in Cardiff - in other words, hardly ever played."

HI. I read this & just had to post. I've lived in Cardiff all my life and was raised in a church called the city temple (Pentecostal). It was the only Church in Cardiff with a C3 and I have fond memories as a young child of sitting near the front on the left just so I could stare at it through the whole service. That would have been late 60's. I couldn't believe that years later when I went back to the church for my sisters wedding that it was gone (early ninties). Absolute sacrilege that they ripped it out on the say so of some guy who told them that it would always continue to 'break down' unless they spent a small fortune on it. That was complete rubbish! Two large wooden cabs were bolted high up on the walls. I think one was an amp the other the leslie. Anyway it wasn't a small church and in the seventies you'd cram around 900 in on some nights. Your right though. It got switched on for 90 mins every sunday. On Wednesdays the organist would come in and sometimes practice whilst a 'youth meeting' took place in the church hall. His name was Kelvin Thomas and I think he worked for the BBC in Llandaff Cardiff. When the old school pastor was not around and he thought no one was listening he would let rip on it like no tomorrow. He wasn't as good as the bloke on youtube (search Old Gal 57 Hammond C3) but I'll tell you he could really make it sing! It was taken out of the church for free. I ask you... anyway I have some photo's of it somewhere. I've also got an old songs of praise video from the early 1980's in which it was used. I might just have to go find that for nostalga's sake. Would love to know what you paid for it given 'they' had it on a free. Regards, Matt.


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