Further Volume Control

[jsharp67]

Hello,


I just got my Further guitar back from Alembic after having some repair work done on the electronics. I did not notice at first, but once I started using the guitar again regularly it seems there is a problem with the volume control. The volume does not decrease until the very last point before it is all the way off. I found the following message from another player that had this issue:


http://alembic.com/club/messages/394/54973.html?1223907345


He tested his volume pot and Mica responded with this:


"Do exactly the same thing, but with the volume control at half rotation to find out interesting things. If it's linear taper, it will be 5K between 1-2 and 2-3. 1-3 should always be 10k. If it's audio taper, 1-2 should be 1-2K and 2-3 should be 8-9K."[/size]


The pot in my guitar is the 475-020 and it tests out as Mica specified above so the taper is correct it also tests out at 10k or zero ohms when full up or down. It also seems to make a little bit of noise in the amp as you turn it up or down.


I know Mica reads these posts so hopefully she will see this and give me some advice.


Thanks and I hope you all have a Happy New Year!

[edwardofhuncote]

She'll no doubt see it and may suggest a better remedy, but step one here is almost always to exercise that pot fifty or so times... fully open, to fully closed. That should clean up the static-y noise, might straighten out the whole issue.

And this'll sound dumb, but I've tried it and it has cured some weirdness before; change the battery. A weak battery makes active electronics do weird stuff.

Happy New Year, when it gets here. 

[jsharp67]

Yessir. I tried all of that. The noisy pot is not the big problem and probably will clear up.


At this point, the volume is basically an on/off switch. This is a big part of my use of this guitar. I use the volume post-effect loop and the ability to lower the volume without decreasing signal to my effects is important. Now it really doesn't decrease at all. It stays the same until the last bit of knob travel and then cuts out quickly.


Thanks for the tips. we'll get it sorted out.   

[JimmyJ]

... I use the volume post-effect loop and the ability to lower the volume without decreasing signal to my effects is important. Now it really doesn't decrease at all...

What does this mean?  How are you able to use this control "post effects"? 

Jimmy J

[FC Bass]

... I use the volume post-effect loop and the ability to lower the volume without decreasing signal to my effects is important. Now it really doesn't decrease at all...

What does this mean?  How are you able to use this control "post effects"? 


Jimmy J

The on board effects loop can be placed pre or post volume: https://club.alembic.com/index.php?topic=256.0

You can see the obel on this page: https://club.alembic.com/index.php?topic=259.0

[JimmyJ]

Oh interesting!  I learn something every day. 

So the function of that onboard volume pot depends on the signal from the last pedal in the FX loop, right?  Could there be an impedance mismatch happening?

Jimmy J

[lbpesq]

The idea behind Garcia’s OBEL was that his pedals would always see the same signal - the full-on pickups.  By doing so, he could more easily replicate his pedal sounds from venue to venue.   I prefer wireless, especially as a singer.  I haven’t been zapped in years!  I had my Further built without the OBEL.   I accomplish the same effect by keeping my guitar volume on “10” most of the time and placing a volume pedal last in my effects chain.

Bill, tgo

[jsharp67]

I don't think so Jimmy. The problem is present with or without the effects loop on. It worked well before. Something has changed. Mica will know what to do.

I also have a volume pedal Bill, but find it hard to make small adjustments. I usually figure to use it for swells, but never do that. 


J.

[lbpesq]

A couple of years ago I discovered the Visual Sound Volume Pedal.  It has a strip of 10 LEDs on the side that help me set the pedal exactly where I want it.   I love this thing!

Bill, tgo

[cntrabssn]

The pot in my guitar is the 475-020 and it tests out as Mica specified above so the taper is correct it also tests out at 10k or zero ohms when full up or down. It also seems to make a little bit of noise in the amp as you turn it up or down.

At what point did you make this measurement, at the volume pot itself or at the guitar output? If you didn’t do so already, could you measure at the guitar main output without plugging the guitar into an amp? You can do this by plugging in a cable and checking across the tip and sleeve. Measure with the volume all the way up, then all the way down.


I may be (way) off base here, but I’m wondering if the input and output pins of the pot somehow got flipped. I’m thinking that the pot wiper (pin 2) should be the output, with pin 1 as the input, and pin 3 grounded. If this is the case and the volume pot is at the last point in the circuit, then you should measure 0 ohms when the volume is completely down. You would also see a decrease in resistance as you go from max to min volume. However if pin 1 is the output, you’ll measure 10k when the volume is completely down. And I don’t think you would see a decrease in resistance as you go from max to min volume.


I realize that this is highly speculative, but checking it might be worth a shot. If I’m right, then I think this ties in with JimmyJ’s impedance mismatch theory.

[jsharp67]

Interesting. I checked resistance at the pins on the pot where they solder into the little circuit board it is mounted to. I'll check it at the output jack and see what it reads.


I believe it is the original volume pot that was in the guitar (it looks like it's been in there awhile). It is soldered to a circuit board, so the pins being reversed there is unlikely. Alembic did the mod to have no gain increase when adding pickups. I wonder if a wire got crossed in that setup? If so, I could fix that.


Thanks, I'll have another look at it.

[mica]

Yes, dad thinks there is a reversed connection. It might be easier to talk it out over the phone, but can you email me a picture of the electronics cavity? There's no size limit on the emails, so the bigger the better

[jsharp67]

Hi Mica,


I can email you some pictures. It's pretty busy in there. I'll try to get some pics in the morning.


I'll pull the harness and get some good pics. I'm pretty good with a soldering iron, if I know which wires to switch. On the other hand, at that point, I can just send the harness back out to you guys. 


Stand by for pics.


J.

[jsharp67]

Hi Mica,


I sent an email to you with some pictures of the electronics. Hope they're OK.


J.

[jsharp67]

This is solved! Thanks to Mica and her Dad for quickly spotting the issue and helping me make the repair myself.

My guitar is back to its good old self and sounds fantastic. What a fine instrument this is. I am so lucky to have it.

It really blows my mind to get such personal service from everyone at Alembic. They treat me like the rockstar I am not. Really great people.

Happy New Year All!

J.