BassInMyFace Posted May 13, 2008 Share Posted May 13, 2008 how simple would it be to add an aux input to an amp? just bought a roland bass cube 100 after lots of consideration. happy with the toys, bells and whistles but absolutely gutted i didnt check that it had an aux input or fx send/return. i do a lot of looping with a pedal and need the output of it to get back in to the amp post eq so that the loops do not get coloured by any pre-amp tinkering (which includes built in effects). with so many nice output features on the amp i assumed it wud cater for this, indeed the smaller cube 30 does have an aux in. i know its not an ideal solution but i really dont want to lose my hard earned cash on reselling the amp and wasting time where i could be playing. how easy/hideously diffficult would it be to fit an input just before the poweramp-speaker stage? in my head its just a simple matter of finding the right place and whacking in a jack socket but i have a feeling you might have a conflicting view........ this is so annoying as i know it's such a standard feature on so many amps, even those less well spec'd as this. what are your thoughts?? Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted May 13, 2008 Share Posted May 13, 2008 I just posted this on your previous thread - may save Dave some time. If you have just bought it, the best option would be to take it back and get the Cube 30, or whatever, as others have said. If that is not an option for you, looking at the amplifier block diagram, the headphone jack mutes the feed to the main amp, so an amp tech might be able to convert the headphone jack into an insert jack, giving you send, return and earth on a three pole jack. That assumes that the headphone amp is a standard op-amp, with enough current drive to power the headphones, in which case the block diagram probably mimics the circuit, and the mute switch is contained within the jack socket. It also assumes that the electronics are modular and some are common to the whole family of amplifiers, so the headphone socket is not embedded on the main motherboard. If it isn't modular, all bets are off. Incidentally, if you were planning to use it with an extension speaker, that may not provide you with any increase in volume. The amp is bridged, and when you plug in an extension speaker, it becomes un-bridged, so each speaker gets its own amp. In other words, if you start with 100 w into 8 ohms, and add another 8 ohm speaker, you get less power out of it, because each amplifier will then see 8 ohms whereas before, each amp saw 4 ohms (half of the single 8 ohms speaker). Quote Link to comment Share on other sites More sharing options...
DHA Posted May 13, 2008 Share Posted May 13, 2008 (edited) [quote name='BassInMyFace' post='197994' date='May 13 2008, 02:27 PM']how simple would it be to add an aux input to an amp? just bought a roland bass cube 100 after lots of consideration. happy with the toys, bells and whistles but absolutely gutted i didnt check that it had an aux input or fx send/return. i do a lot of looping with a pedal and need the output of it to get back in to the amp post eq so that the loops do not get coloured by any pre-amp tinkering (which includes built in effects). with so many nice output features on the amp i assumed it wud cater for this, indeed the smaller cube 30 does have an aux in. i know its not an ideal solution but i really dont want to lose my hard earned cash on reselling the amp and wasting time where i could be playing. how easy/hideously diffficult would it be to fit an input just before the poweramp-speaker stage? in my head its just a simple matter of finding the right place and whacking in a jack socket but i have a feeling you might have a conflicting view........ this is so annoying as i know it's such a standard feature on so many amps, even those less well spec'd as this. what are your thoughts??[/quote] You would need to find a circuit diagram and locate the pre-amp output and add a switching jack. BUT this is not the best way to add an effects loop as there should really be some impedance matching and level recovery circuit. I would not recommend trying to add a loop without using an active design. I would consider taking it back to where to got it from and seeing if they will do a deal on a swap. Sorry. Dave Edited May 13, 2008 by DHA Quote Link to comment Share on other sites More sharing options...
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