Neil Robinson
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Subsequent to my post number 10 in this topic http://www.gscalecentral.net/m12161...hargeable batteries to power the booster amp.
Audio booster amplifier advice required.
- Thread starter Neil Robinson
- Start date
nicebutdim
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I'm not sure if this will help; http://www.maplin.co.uk/three-way-12db-octave-150w-3389 < Link To http://www.maplin.co.uk/t...-12db-octave-150w-3389 Basically it's a car audio crossover, used to supply different size speakers with different frequencies. If you were to try the mid range output it may filter out the low frequencies. Please not that I do say 'may', if the hum is of a higher frequency then the sound will still be there, and worse still it may even block some of the sounds that you actually want to use.
Is there no way of smoothing the supply into the sound chip by using a large capacitor or similar?
Is there no way of smoothing the supply into the sound chip by using a large capacitor or similar?
New Haven Neil 2
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Ah, a hum loop. It needs to be de-coupled somehow, but I can't remember enough from radio bodging teenage days how to do it! Don't we have some radio amateurs on here? Normally I'd ask you, Neil!
Neil Robinson
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We seem to be thinking along similar lines Neil.New Haven Neil 2 said:
The amplifier design ( http://www.datasheetcatalog.org/datasheet/philips/TDA7056B_3.pdf < Link To http://www.datasheetcatal...philips/TDA7056B_3.pdf ) specifies a 0.47 micro F capacitor on the input terminal, I guess this is for decoupling. I tried putting a 0.1micro F in the input to the ground as well as another on the ungrounded input to no avail.
New Haven Neil 2
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Had a quick scan about, most of what I see seems to involve separate power supplies.
I wondered if linking the earthy sides of the two boards together with another wire may help - rather than just the -ve of the signal lead?
Are the boards isolated from the frame? I was wondering if there is a return there somewhere. Which leads me on to think you probably are testing this on the bench and not in the loco!
Not really much help, I think I'm trying to teach granny......
I wondered if linking the earthy sides of the two boards together with another wire may help - rather than just the -ve of the signal lead?
Are the boards isolated from the frame? I was wondering if there is a return there somewhere. Which leads me on to think you probably are testing this on the bench and not in the loco!
Not really much help, I think I'm trying to teach granny......
Neil Robinson
Registered
Thanks for your comments.
These prompted me to research hum loops.
However I've had no success to date using the information so gained to this application.
I haven't tried using the chip +ive and _ive terminals to power the booster amp for fear of overloading the chip. I think the amp would need a greater current and voltage than the Bachmann chip could provide. After all it was intended for the smaller scales, IMHO the crux of the problem.
Attached is a simplified diagram of the system.
I've pretty much resolved to use 10 rechargeable low self discharge AA cells to power the booster amp. It works O.K with a 9V PP3 type battery but I can't imagine that working for long without needing to be recharged.
These prompted me to research hum loops.
However I've had no success to date using the information so gained to this application.
I haven't tried using the chip +ive and _ive terminals to power the booster amp for fear of overloading the chip. I think the amp would need a greater current and voltage than the Bachmann chip could provide. After all it was intended for the smaller scales, IMHO the crux of the problem.
Attached is a simplified diagram of the system.
I've pretty much resolved to use 10 rechargeable low self discharge AA cells to power the booster amp. It works O.K with a 9V PP3 type battery but I can't imagine that working for long without needing to be recharged.