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[Big_Al]

hi guys,
            a bit of advice required if anyone can help .

Need to slightly modify my "portable"  battery powered  guitar amp & backing track playback system that I have constructed to be able to play anywhere outside without mains power .

This comes to light from yesterdays system  try out session at the Wycombe meet .

The small 12v powered amplifier that I have has a decent guitar channel with good EQ etc. as well as a MP3 /CD input for playing the backing tracks .

BUT . . . This MP3 /CD input has no level control at all . I am using both my old Sony "walkman" minidisc player & my newish Samsung galaxy  7" tablet to supply the backing tracks .

It seems the levels of these tracks are at many slightly different output levels & although there is volume adjustment  on both, these are difficult to adjust quickly & accurately from either the walkman or the  tablet themselves between tracks .

The connection lead from these devices is simply a 3.5mm stereo jack plug & is taken from the headphone out sockets on these.

Question is can I make up a 3.5mm stereo jack lead with a simple passive rotary volume pot in the line for easy & quick adjustment  of the level ?

If so what type of pot do I need & how do i wire it ?

TIA to any electronics wiz who can sort this for me     Regards, Al

[Broomies Mate]

Summat like this? 

http://www.t2retail.co.uk/Wired/Volume-Control-Cable-for-Stereo-Headphones

[AndyRoid]

Question is can I make up a 3.5mm stereo jack lead with a simple passive rotary volume pot in the line for easy & quick adjustment  of the level ?

You could, but it wouldn't be very effective, you wouldn't be able to get any volume boost if you have a track that is particularly quiet, and the potential for impedance mismatch is right up there with that scenario.

Something like the FiiO E5 Headphone Amplifier will do just what you want, and the battery lasts all day with ease (I used to use one before I started boosting the output volume on the phone itself).

I may still have one kicking around somewhere, if I do then you can have it.



EDIT:

Just found it, it's the FiiO E6 I have.
PM me your addy and I'll pop it in the post.

[Big_Al]

Question is can I make up a 3.5mm stereo jack lead with a simple passive rotary volume pot in the line for easy & quick adjustment  of the level ?

You could, but it wouldn't be very effective, you wouldn't be able to get any volume boost if you have a track that is particularly quiet, and the potential for impedance mismatch is right up there with that scenario.

Something like the FiiO E5 Headphone Amplifier will do just what you want, and the battery lasts all day with ease (I used to use one before I started boosting the output volume on the phone itself).

I may still have one kicking around somewhere, if I do then you can have it.



EDIT:

Just found it, it's the FiiO E6 I have.
PM me your addy and I'll pop it in the post.

Wow!     Thanks Opimal . . .  once again OOF at it's best 

Would like to try it & if it does what I need , would like to offer you something for it at least 

PM being sent now .    thanks very much ,  regards,   Al 

[Big_Al]

Summat like this? 

http://www.t2retail.co.uk/Wired/Volume-Control-Cable-for-Stereo-Headphones

hi BM  . . .I  need something that has quite a large "Knob"  on   . . . excuse my french . . . but I may need to adjust it while playing sometimes .

Was thinking along the lines of how the volume control works on the actual guitar pick up's .

Think I may have been sorted by a very kind offer from  Optimalkiller  though.

[zirk]

You could make up a very simple and cheap Passive Mixer to fed to Filo or MP3 Amp in, that way you could pre set the input level from each devise separately.

I draw something and post it in a minuet. Chris.   

[zirk]

Something like this, 3 x 10K Volume Pots or sliders (Logarithmic), this way the output impedance should be fairly constant.

[albitz]

I want one of those Zirk. Make me one,theres a good fella.
The only time I bother picking up  guitar is to play along to music on youtube.Obviously the volume of the amp (even very low) drowns out the speaker on my laptop. Hence the last time I bothered trying was the Christmas before last.

[Big_Al]

Thanks Chris,
                      seems simple enough. But  I could be totally wrong here , that sketch looks like mono . Is it just the case of converting the  stereo lead from the device (stereo . . .2 x  hot tips  & 2 commons to a mono plug with the 2 hots linked to the one hot tip of a mono plug ?

Presume it will be 3.5 stereo plugs in & out from the FiiO as well

Also which tag on the pots  . . thinking theres usually 3 ?  or are these all linked  & any one will do ? 

Although I used 2 devices yesterday  . .   it is my plan to use just the tablet as I can get all my backing tracks  (250 odd) on the one device in various playlist formats.

The problem with tablet is altering the volume is very hap hazard  . . .either full on  or almost off  . . it is difficult to get a small defined adjustment with out fiddling for a second or two   . . probably because of my "banana sized " fingers 

[Big_Al]

I want one of those Zirk. Make me one,theres a good fella.
The only time I bother picking up  guitar is to play along to music on youtube.Obviously the volume of the amp (even very low) drowns out the speaker on my laptop. Hence the last time I bothered trying was the Christmas before last.

Sorry Albs  ,     only available from Zirk & Essex Al  (patented & copyrighted)   Enterprises 


albs tried taking a 3.5 mm stereo jack from your compuer headphone /line out & putting into your stereo aux input .I've  been doing that for  years now  . . .seems to work well for practice purposes  unless your using a Marshall stack or similar for practice

[AndyRoid]

hi BM  . . .I  need something that has quite a large "Knob"  on   . . . excuse my french . . . but I may need to adjust it while playing sometimes .

Was thinking along the lines of how the volume control works on the actual guitar pick up's .

Think I may have been sorted by a very kind offer from  Optimalkiller  though.

That might be an issue for you, the volume control on the FiiO is a 64 step "up/down button" type.

[hercules]

id personally set up a series of resistors and link them to the tablet through a circuit protection device to allow for the note C minor,on the pre out volume I would run it through a 40watt monofilament bulb to reduce the impedance and amalgamate a varied magnitudal ampage inverter switched simply through a 3 way rocker switch 
simple really 

[AndyRoid]

The problem with tablet is altering the volume is very hap hazard  . . .either full on  or almost off  . . it is difficult to get a small defined adjustment with out fiddling for a second or two   . . probably because of my "banana sized " fingers 

You should be ok with the FiiO once you get used to the volume control, it's a 64 step jobby so adjustment can be quite made in quite small increments.

[zirk]

Thanks Chris,
                      seems simple enough. But  I could be totally wrong here , that sketch looks like mono . Is it just the case of converting the  stereo lead from the device (stereo . . .2 x  hot tips  & 2 commons to a mono plug with the 2 hots linked to the one hot tip of a mono plug ?

Presume it will be 3.5 stereo plugs in & out from the FiiO as well

Also which tag on the pots  . . thinking theres usually 3 ?  or are these all linked  & any one will do ? 

Although I used 2 devices yesterday  . .   it is my plan to use just the tablet as I can get all my backing tracks  (250 odd) on the one device in various playlist formats.

The problem with tablet is altering the volume is very hap hazard  . . .either full on  or almost off  . . it is difficult to get a small defined adjustment with out fiddling for a second or two   . . probably because of my "banana sized " fingers 

Yep, mono, is your Amp stereo?, if so just double up with Dual Gang Pots or Sliders (Sliders can go noisy after a while due to the crap that can get in them), being Logarithmic you need to wire them correctly, as you say 3 pins per channel, the sliders are normally marked which one needs to go to ground, the Pots with 3 pins work as per Volume control so as you look down on it from the front, left would be ground, centre i/p and right o/p ie clockwise, if that makes sense..

If your amp is mono, which I suspect it is, then just short Left and Right on all the inputs jacks. 

On the level side just put your devices on near full volume and let the mixer do the rest.

[albitz]

I want one of those Zirk. Make me one,theres a good fella.
The only time I bother picking up  guitar is to play along to music on youtube.Obviously the volume of the amp (even very low) drowns out the speaker on my laptop. Hence the last time I bothered trying was the Christmas before last.

Sorry Albs  ,     only available from Zirk & Essex Al  (patented & copyrighted)   Enterprises 


albs tried taking a 3.5 mm stereo jack from your compuer headphone /line out & putting into your stereo aux input .I've  been doing that for  years now  . . .seems to work well for practice purposes  unless your using a Marshall stack or similar for practice

In simple terms. Wee small jack at one end of the lead,and a big one on the other end,yes ?  .....are such leads generally available.
The amp is a Marshall btw..............................................................................10w practice amp.