Hammond T202

[Gleeman]

Anyone know anything about these? I think they're the last tonewheel organs, and I can pick one up cheaply.

Are they worth having if put through a Leslie? Or should I spend more and get better?

[Lento]

I'd personally hold out for at least an M 100 or 102 (Procul Harum's "A Whiter shade of pale" was recorded with an M102)
Plus, you get to use some valves!

As for the leslie, yes, anything sounds better going through a leslie. A 145, or 147 are the ones to get if your budget allows.

Lyn

[Gleeman]

Thanks — I'll give this one a miss.

[SunShineState]

As the other guy implies I think these were tonewheel organs (so worth having in my opinion) but with transistor amps, rather than valve - maybe not that big a deal as some of the big classic hammonds had no amps at all and had to be fed into valve leslies. Also I think some of these had small "leslies" or at least a rotating speaker built in?

Also worth noting that the smaller organs (2x 61 keys I think) have a smaller complement of tone wheels so don't quite have the sound of the A/B/C series.

Prob still sounds pretty good though if it has tonewheels at all....

There are def some hammonds to be avoided -1980's jap ones that are fully electronic and dont sound anything like a hammond whatsoever!

Cheers

[The Elf]

The Hammond T202 is essentially the organ used by Tony Banks of Genesis in the mid to late 1970s (he actually used a T102, but there's very little difference other than a built-in Leslie). I have a T202 and I love it to bits - I recently had a line output fitted in place of the near-useless headphone output and I run it through a BOSS CE1 and an MXR Phase 100 for the true Tony Banks experience - fantastic!!

[Hugh Robjohns]

...some of the big classic hammonds had no amps at all and had to be fed into valve leslies.

All tonewheel Hammonds had 'amps' -- meaning preamplifiers. The earlier (nicer) ones had valve preamps. Later ones, like the T series, had transistor preamps, which don't sound as nice to many people's ears. Some early Hammonds had built in (valve) power amps and speakers (like the A100), but most required external speaker cabinets and power amps. Hammond made their own, but Leslie cabinets quickyl became more popular. Again, some had valve amps and some solid-state amps.

The T series had builtin solid state amps and speakers, plus a very crude Leslie system. Doesn't sound as nice as a proper B3/122 combination, but okay for a home instrument.

Also worth noting that the smaller organs (2x 61 keys I think) have a smaller complement of tone wheels so don't quite have the sound of the A/B/C series.

The full console organs had 2x61 note keyboards. The smaller 'Spinet' models, like the T series, had offset 44 note keyboards. Some did have fewer tonewheels, but more significantly, they generated different frequencies, offering more brilliance in many cases. That's one of the main reasons why they sound so different.

hugh

[The Korff]

Bamp!

I just got a T202 for free (whoop!) and it's been an awful lot of fun so far It's in great nick, and sounds awesome, but one of the pedals is a bit flakey; you have to press it quite hard, or it either doesn't sound or seems to have a bit of a delay between pressing and sounding. Does anyone know what the matter with it might be? I'm guessing it's just a slightly dodgy switch or contact and could be fixed quite easily...

Cheers!

CHris

[Hugh Robjohns]

If it's only one pedal then it can really only be a dodgy contact in the pedal assembly or its assiciated buffer circuit... but a dirty switch is by far the most likely.

I've got the schematics for the T200 somewhere... I'll send them over...

Hugh

[The Elf]

Wow!

Mine was nearly free, but the 350 quid repair bill certainly hurt!

The pedal should be a very easy fix.

Some day I'd like to get the amp in mine working properly again, which failed shortly after having the headphone jack converted to a line output. The engineer that looked at it was baffled as to the cause. I don't suppose the diagrams you have might include the T202's amp circuitry would it Hugh?

[Hugh Robjohns]

Yes, but the whole lot is 77MB, so rather than send it to you directly, you can download all the circuitry schematics and service info you need here:

http://captain-foldback.com/Hammond_sub/tseries/XTP_partial_service_manual.zip

http://captain-foldback.com/Hammond_sub/schematics/t100series

Note that the schematics are GIF files which are too big to open in Windows Explorer, so download them as files and then convert to something more usable.

hugh

[The Elf]

Thanks Hugh - I'll hand these to my friendly local solder monkey and see if he can make use of them!

[Hugh Robjohns]

Some day I'd like to get the amp in mine working properly again, which failed shortly after having the headphone jack converted to a line output. The engineer that looked at it was baffled as to the cause.

It's a pretty simple transistor amp, although it retains an old-schol transformer-coupling with feedback to the push-pull output transistors. The power amp stage also includes the reverb amp driver and return mixing circuitry, so the easiest way of deriving a line output would be to tap off the output of the main amp and simply pad it down to an appropriate level.

If you wanted to be able to kill the organ speakers when using the line output that gets more complicated because you'd have to either provide a dummy load in place of the speakers, or modify the amp circuitry to isolate the output transistors to avoid killing them when off load.

hugh

[The Elf]

Some day I'd like to get the amp in mine working properly again, which failed shortly after having the headphone jack converted to a line output. The engineer that looked at it was baffled as to the cause.

It's a pretty simple transistor amp, although it retains an old-schol transformer-coupling with feedback to the push-pull output transistors. The power amp stage also includes the reverb amp driver and return mixing circuitry, so the easiest way of deriving a line output would be to tap off the output of the main amp and simply pad it down to an appropriate level.

If you wanted to be able to kill the organ speakers when using the line output that gets more complicated because you'd have to either provide a dummy load in place of the speakers, or modify the amp circuitry to isolate the output transistors to avoid killing them when off load.

hugh

My limited electronics knowledge leaves much of that Greek to me, I'm afraid! Sorry!

But I'm interested by this bit:

you'd have to either provide a dummy load in place of the speakers, or modify the amp circuitry to isolate the output transistors to avoid killing them when off load.

The guy that did the mod is a bit of a knowledgeable hacker, but not an expert. The loading thing was never mentioned while he was doing the (very simple) mod for me. He set the headphone jack up as a stereo socket. Tip gives me a line output and ring gives (well, 'gave') me an input to the Leslie. But after a week or two of perfect working order the amp just went into permanent distortion. How and where he tapped the signal is a mystery to me.

One good aspect of the failure is the end of the whirring Leslie motor, but I really should re-fit the baffle some day (it lives in my garage).

If there's anyone in the South Yorkshire area who understands Hugh's explanation - heeeeeeeelp!!! I'm happy to pay for a repair, as long as you can come and do it in situ!

[Hugh Robjohns]

Sounds like the output transistors have suffered.

The standard configuration is for the output transistors to feed the static speakers via a switch on the headphone socket. If you plug headphones in the signal is fed through the phones and back through a 300ohm resistor to provide some attenuation and set a minimum output loading.

If you don't plug headphones in the signal is passed straight to the two parallel internal 12 inch speakers.

If you select the Leslie the speaker signal is still sent to the internal speakers (but via a chunky inductor/capacitor filter), and also to the internal (or external) leslie speaker.

The internal Leslie has no amp of its own so needs a speaker-level feed -- so I'm not sure what you expected your leslie input to do.

hugh

[The Elf]

The internal Leslie has no amp of its own so needs a speaker-level feed -- so I'm not sure what you expected your leslie input to do.

My sloppy wording I'm afraid. The new input gave me access to the Hammond's amp (not just the Leslie) - and it worked perfectly like that for a couple of weeks, allowing me to send sounds into either the straight speaker, or the Leslie by flicking the Hammond's speaker selection rocker switch. So the feed must be ahead of the amp.

It wasn't something I wanted or needed, but the guy said it was easy to do while he was at it, and it might be useful - and I agreed that it might.

[Hugh Robjohns]

Ah, okay.

The amp input circuitry is complicated by the way it combines the signals from organ, pedal percussion and reverb. It is certainly possible to derive a line output and provide an amp input by hacking the front end of the amp circuitry, but it would be a hack.

If your amp is dead then it's more probable that a wire has dropped off or something silly has happened with the front end of the amp.

Hugh

[Folderol]

Does anyone mind if I just sit here and drool

[The Elf]

If your amp is dead then it's more probable that a wire has dropped off or something silly has happened with the front end of the amp.

It's not dead, but very heavily distorted (and not even a 'good' distortion, unfortunately). The modder spent three separate nights trying to track the problem down, but couldn't fix it, so it has stayed this way for a few years now. When it was clear it wasn't going to be fixed I asked him to just disable the Leslie motor and put the organ back together. Since then I've only ever used the line output.

[Folderol]

Yes, but the whole lot is 77MB, so rather than send it to you directly, you can download all the circuitry schematics and service info you need here:

http://captain-foldback.com/Hammond_sub/tseries/XTP_partial_service_manual.zip

http://captain-foldback.com/Hammond_sub/schematics/t100series

Note that the schematics are GIF files which are too big to open in Windows Explorer, so download them as files and then convert to something more usable.

hugh

Drawings snaffled for some light bed-time reading

[Hugh Robjohns]

It's not dead, but very heavily distorted (and not even a 'good' distortion, unfortunately).

Hmmm.... I'm sure its fixable, but not remotely. Without knowing what his modification was it's difficult to guess what might have gone wrong, but I'm thinking possibly a biasing issue at the front of the amp as a result of his modification, or just a natural faling of something at the front end.

Is the original headphone socket and its associated wiring still intact, or did he mess around with that too? I'm wondering if he inadvertantly did something odd there that eneded up cooking the output drivers?

hugh

[The Elf]

Is the original headphone socket and its associated wiring still intact...?

No - the socket was replaced with the stereo socket: tip = line out, ring = amp in. It was a neat way to avoid making any new holes in the organ!

Really appreciate the brainwork and advice, Hugh. It's inspiring me to get off my bum and fix this thing one way or the other!

One of the forum regulars (not named unless he is happy for me to do so?) has offered to come take a diagnostic look when he's near my toadstool in June. Isn't this a lovely place?!

[Hugh Robjohns]

Excellent -- there are some really great people around here, you're right. I wish you (and he) all success!

hugh

[Folderol]

No problem with being named and shamed
I just didn't want you to feel obliged if it wasn't convenient.

I'm hoping it isn't the output transistors. The fact that they were PNP types warned me, and looking at the base-emitter voltages confirmed that they are germanium types, what doesn't help is that they are using some obscure part number - still they may be something like AD149 which surprisingly are still available!

[JKleban]

Hugh,

The T has a transistor amp and there is NO PROBLEM in disconnecting the speakers.

I have an old T as well but it took about $800 USD to get it up and running correctly and to have a 9 pin LESLIE kit installed. The built in LESLIE starting with the 2 series uses a real small speaker and has no horns and only one drum... OK for built in but the T sounds best through a LESLIE CAB... the 760 (another tranny) is a good match up to the T and is what T Banks used back in the classic days when he used the T.

Jim

[The Red Bladder]

The economic crisis is shaking a shed load of good stuff out of people's attics and spare rooms, so no shortage of Hammonds nowadays -

Ebay Listing HERE