JakeBrownBass Posted January 15, 2009 Share Posted January 15, 2009 So then, just wondering if anybody knows of a schematic that will do the following 2 switchable inputs with 1 output. With 2 separate volume controls with the 2 inputs. Thats simple enough, but what would be ace is to have a headphone output on the pedal with its own volume?? Added diagram Would be great if someone could point me in the right direction! Cheers Jake Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted January 15, 2009 Share Posted January 15, 2009 [quote name='jake_tenfloors' post='381769' date='Jan 15 2009, 09:50 PM']So then, just wondering if anybody knows of a schematic that will do the following 2 switchable inputs with 1 output. With 2 separate volume controls with the 2 inputs. Thats simple enough, but what would be ace is to have a headphone output on the pedal with its own volume?? Added diagram Would be great if someone could point me in the right direction! Cheers Jake[/quote] The attached link to a Talkbass member's web pages gives a Hi-Z input circuit which would fit between a passive instrument and your volume control - two of these will give you two inputs - [url="http://personalpages.tds.net/~fdeck/bass/quickand.pdf"]http://personalpages.tds.net/~fdeck/bass/quickand.pdf[/url] The attached link to the headwise web pages gives a one op-amp per channel headphone amplifier circuit - I built one, and the bass depth and clarity is amazing - [url="http://www.headwize.com/projects/cmoy2_prj.htm"]http://www.headwize.com/projects/cmoy2_prj.htm[/url] Both circuits will work on a 9v battery supply. Quote Link to comment Share on other sites More sharing options...
JakeBrownBass Posted January 15, 2009 Author Share Posted January 15, 2009 thanks for the quick response! That first circuit you posted, the guy says he really recommends that its only used with piezo pickups? Could i use a design like this?? But the outputs as inputs and vice versa?? Then could it be as simply as adding a pot after each input?? Then for the headphone output, use a simple op-amp amplifier circuit?? Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted January 16, 2009 Share Posted January 16, 2009 [quote name='jake_tenfloors' post='381891' date='Jan 15 2009, 11:23 PM']...That first circuit you posted, the guy says he really recommends that its only used with piezo pickups?...[/quote] If you check out the high pass filter preamp on his site, the main difference is that he has a capacitor in series with the input. If you have an active bass, it probably has a capacitor on the output anyway, so you would need to try it and experiment if required. [quote name='jake_tenfloors' post='381891' date='Jan 15 2009, 11:23 PM']Could i use a design like this?? But the outputs as inputs and vice versa?? Then could it be as simply as adding a pot after each input??[/quote] Yes for active basses, which have enough current drive, but no for passive basses, where the low impedance of the pot would suck most of the tone out of your sound Quote Link to comment Share on other sites More sharing options...
JakeBrownBass Posted January 16, 2009 Author Share Posted January 16, 2009 [quote name='Mottlefeeder' post='382003' date='Jan 16 2009, 08:08 AM']If you check out the high pass filter preamp on his site, the main difference is that he has a capacitor in series with the input. If you have an active bass, it probably has a capacitor on the output anyway, so you would need to try it and experiment if required. Yes for active basses, which have enough current drive, but no for passive basses, where the low impedance of the pot would suck most of the tone out of your sound[/quote] Ok, i'm with you! Now with the passive problem, what can i use to boost the signal without loosing the tone?? An op-amp like with the headphones?? Just so i can make one channel switchable between active & passive. Gonna have to start drawing some designs up me thinks! Jake Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted January 16, 2009 Share Posted January 16, 2009 [quote name='jake_tenfloors' post='382055' date='Jan 16 2009, 09:19 AM']Ok, i'm with you! Now with the passive problem, what can i use to boost the signal without loosing the tone?? An op-amp like with the headphones?? Just so i can make one channel switchable between active & passive. Gonna have to start drawing some designs up me thinks! Jake[/quote] I'm fairly confident that the Fdeck Hi-pass filter front end would work for passives, and if it overloaded, would have a 'nice valve-like' distortion. See the last paragraph. Alternatively [url="http://www.diyaudio.com/forums/showthread.php?threadid=75949"]http://www.diyaudio.com/forums/showthread.php?threadid=75949[/url] is a thread about onboard preamps which may give you some ideas for the front end. If not, the site contains several other threads about bass and guitar amplification, but you have to register, and I seem to have lost my password... Alternatively, the Albert Kreuzer outboard preamp referred to in the above thread is filed here [url="http://www.albertkreuzer.com/pics/el/pre/schem/preamp_sch21.gif"]http://www.albertkreuzer.com/pics/el/pre/s...reamp_sch21.gif[/url] The front end runs at +9 volts (I think), but the op-amps need +/- supplies. Quote Link to comment Share on other sites More sharing options...
bass_ferret Posted January 16, 2009 Share Posted January 16, 2009 Just get an EBS Microbass II, or lots of other multi channed preamps. Sansamp? Quote Link to comment Share on other sites More sharing options...
JakeBrownBass Posted January 17, 2009 Author Share Posted January 17, 2009 [quote name='bass_ferret' post='382924' date='Jan 16 2009, 11:55 PM']Just get an EBS Microbass II, or lots of other multi channed preamps. Sansamp?[/quote] Thats my ideal, but i'm really skint atm so was looking at some cheaper alternatives as i've got free access to most components. Jake Quote Link to comment Share on other sites More sharing options...
StanRobinson Posted January 23, 2009 Share Posted January 23, 2009 Try Red Onion [url="http://www.redonionsolutions.co.uk/Index.htm"]Red Onion[/url] Cheers, SR Quote Link to comment Share on other sites More sharing options...
Al Heeley Posted January 23, 2009 Share Posted January 23, 2009 [quote name='jake_tenfloors' post='383213' date='Jan 17 2009, 01:29 PM']...as i've got free access to most components.[/quote] Jeez - wish I'd known that a couple of months ago before I went on my stompbox building spree! Had to remortgage the house to pay off my Maplins habit. Quote Link to comment Share on other sites More sharing options...
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