No way to find out any schematics for this Box!
i629.photobucket.com/albums/uu13/DogCake24/Bell%20ADT/ADT7b.jpg
Bell Electrolabs - A.D.T
Hi, I have a problem with my Bell ADT, is a kind of Phase Shifter and the overall modulation is distorted and noisy.
No way to find out any schematics for this Box!
i629.photobucket.com/albums/uu13/DogCake24/Bell%20ADT/ADT1c.jpg
i629.photobucket.com/albums/uu13/DogCake24/Bell%20ADT/ADT7b.jpg
No way to find out any schematics for this Box!
i629.photobucket.com/albums/uu13/DogCake24/Bell%20ADT/ADT7b.jpg
Hi, I have a problem with my Bell ADT, is a kind of Phase Shifter and the overall modulation is distorted and noisy it seems to be related to the Voltage which controls the CD4006 or the CD4006 by itself.
Any suggestions ?
Does exist any chance to find schematics ?
Thanks in advance
MF
Any suggestions ?
Does exist any chance to find schematics ?
Thanks in advance
MF
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RnFR
- Old Solderhand
Information
i don't think we have a scheme for that model yet. one way to get the ball rolling would be to post detailed pics of the component and track side of the board, as well as post any component values that may be hard to see.
it looks like a cool box!
moved to vintage section.
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topics merged. please keep all information in a single topic, thank you!
it looks like a cool box!
moved to vintage section.
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topics merged. please keep all information in a single topic, thank you!
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Dirk_Hendrik
- Old Solderhand
Information
That's no phaser buddy. With those chips it's worth a date with any erotic topmodel.
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SPeter
- Cap Cooler
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grizzlytone
- Breadboard Brother
Yeah, those SAD512 is hard to find these days....
In the pics it looks as if it might be a crack on the MC3403 chip.
If you make a close inspection you should be able to determine if it is a crack or if it is just a superficial scratch.
Replacing the IC (standard configuration OP-amp if memory serves me right) is an easy 5 minute fix if you're handy with a soldering iron and a good quality desoldering braid.
Put in an IC socket while you're at it and replace the IC with a pin-correct equivalent if you have trouble sourcing the MC3403
Seems likely that the BBD's is not running right -they are prone to noise and distortion even when running on optimal conditions, if the clock driving the bucket brigade action (from an oscillator circuit of witch the MC3403 might be a part)is out of range you'd still have a audio signal passing thru but very much degraded in quality and the delay time would be altered in such a way that if the clock is too fast the summed signal from the delay line and the dry signal would add up to a phasing sound, (like in your description), and if the delayed signal is to slow you'd hear a discrete echo instead of the chorus sound witch I think is what Automatic Double Tracking means....(were they trying to avoid litigations from Roland/BOSS at the time?)
Do you know the previous history of the device? i.e. have you ever had it work right?
If not, chances are that some previous owner tried powering it with the wrong voltage -it is under these conditions I've seen IC's crack....
Good luck brother/ M
In the pics it looks as if it might be a crack on the MC3403 chip.
If you make a close inspection you should be able to determine if it is a crack or if it is just a superficial scratch.
Replacing the IC (standard configuration OP-amp if memory serves me right) is an easy 5 minute fix if you're handy with a soldering iron and a good quality desoldering braid.
Put in an IC socket while you're at it and replace the IC with a pin-correct equivalent if you have trouble sourcing the MC3403
Seems likely that the BBD's is not running right -they are prone to noise and distortion even when running on optimal conditions, if the clock driving the bucket brigade action (from an oscillator circuit of witch the MC3403 might be a part)is out of range you'd still have a audio signal passing thru but very much degraded in quality and the delay time would be altered in such a way that if the clock is too fast the summed signal from the delay line and the dry signal would add up to a phasing sound, (like in your description), and if the delayed signal is to slow you'd hear a discrete echo instead of the chorus sound witch I think is what Automatic Double Tracking means....(were they trying to avoid litigations from Roland/BOSS at the time?)
Do you know the previous history of the device? i.e. have you ever had it work right?
If not, chances are that some previous owner tried powering it with the wrong voltage -it is under these conditions I've seen IC's crack....
Good luck brother/ M
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fosnal1950
- Breadboard Brother
That's a delay and an excellent sounding one as well !
ADT stands for automatic double tracking. I heard it when it was first introduced and was impressed by it I remember. If the parts were available I would really like to build one.
Alf
ADT stands for automatic double tracking. I heard it when it was first introduced and was impressed by it I remember. If the parts were available I would really like to build one.
Alf
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biliousfrog
- Resistor Ronker
Information
- Posts: 341
- Joined: 31 Aug 2012, 13:29
- Completed builds: Zen Drive, Fuzz Factory, Really Cheap Compressor, D*A*M 66, Klon Buffer, CryBaby mods, Boss TR2 mods, Various loops and switchers, DOD250, Fulltone Bass Drive, MXR Bluebox mods
- Location: Lowestoft - UK
- Has thanked: 5 times
- Been thanked: 9 times
- Contact:
Sorry to dig up this old thread.
I've had one of these on a shelf in my leaky shed for several years - thankfully, it was in a dry spot
I didn't realise that these were particularly desirable and was contemplating stripping it of anything useful and dumping it. I opened it up, saw the tropical fish capacitors and strange IC's and thought I'd better Google it...first few hits were an eBay listing for one that sold for £350, a thread on Killing Joke's gear and this...haha 
I need to clean it up a bit, then I'll sell it on. A friend gave it to me many years ago in exchange for something, I stuck it in a rackmount guitar rig, then stored it away until now. It's got some screws, jack socket nuts and a knob missing but, hopefully, should still be working.
Mine is a PA:CE model BTW.
I've had one of these on a shelf in my leaky shed for several years - thankfully, it was in a dry spot
I didn't realise that these were particularly desirable and was contemplating stripping it of anything useful and dumping it. I opened it up, saw the tropical fish capacitors and strange IC's and thought I'd better Google it...first few hits were an eBay listing for one that sold for £350, a thread on Killing Joke's gear and this...haha I need to clean it up a bit, then I'll sell it on. A friend gave it to me many years ago in exchange for something, I stuck it in a rackmount guitar rig, then stored it away until now. It's got some screws, jack socket nuts and a knob missing but, hopefully, should still be working.
Mine is a PA:CE model BTW.
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biliousfrog
- Resistor Ronker
Information
- Posts: 341
- Joined: 31 Aug 2012, 13:29
- Completed builds: Zen Drive, Fuzz Factory, Really Cheap Compressor, D*A*M 66, Klon Buffer, CryBaby mods, Boss TR2 mods, Various loops and switchers, DOD250, Fulltone Bass Drive, MXR Bluebox mods
- Location: Lowestoft - UK
- Has thanked: 5 times
- Been thanked: 9 times
- Contact:
Here's a video demo of mine which is going on eBay later today