Kick's first build LP-1MQ Red Widow

[Simon Barden]

Looking great, Kick. Glad it's trouble free. I'm assuming that you also put the copper tape on the back of the control cavity covers (just mentioning this for others reading the page).

Looking tidy Kick, fret levelling is not one of the jobs I have ventured to try yet, but I know I must one day,

It always sounds scary but it's actually a lot easier to do than you'd think. You just need a couple of the right tools and a bit of common sense and it almost does itself.

[Dedman]

looking fantastic Kick!

[Kick]

Hm... I couldn't resist it and I put some strings on it to check if everthing was ok. Unfortunately, there is something weird going on.

One volume pot is ok (bridge) and one tone pot is ok (neck). The bridge tone does not do anything. I hear no difference in the output when I turned the knob. And the neck volume pot is doing something weird; when full open I have output. When I turn it down the output is muted when I'm halfway and when I turn it down further the output comes back. It als makes some weird clicking sound in middle position.

Definately something I have done wrong while watching the videotutorials. I have to check to see what went wrong...

@Simon: I did not have enough coppertape to cover the covers. But I can use other metal tape as well I reckon?

[DaveC64]

Hm... I couldn't resist it and I put some strings on it to check if everthing was ok. Unfortunately, there is something weird going on.

One volume pot is ok (bridge) and one tone pot is ok (neck). The bridge tone does not do anything. I hear no difference in the output when I turned the knob. And the neck volume pot is doing something weird; when full open I have output. When I turn it down the output is muted when I'm halfway and when I turn it down further the output comes back. It als makes some weird clicking sound in middle position.

Definately something I have done wrong while watching the videotutorials. I have to check to see what went wrong...

@Simon: I did not have enough coppertape to cover the covers. But I can use other metal tape as well I reckon?

I know you found that you had swapped the a and b types around but that would not cause the click around mid point nor the muting. The Type A is a logarithmic potentiometer so that your ears can hear the volume go up smoothly. If you use the linear pot type B for the volume it will be to loud when it is set low and have a very poor range when you adjust it. If the carbon track is broken in the pot you may experience a click and some strangeness with the volume. Check the resistance from the 2 outside pins it should be 500k with nothing attached than move the pot fully clock wise check the resistance between the 1st pin and the 2nd pin should be more or less a short circuit and 1st pin and 3rd pin should be 500k. then turn it anti clock wise pin 1 and 2 should read 500k pin 2 and 3 short circuit. move the pot to centre and you should read approx 50k to from pin 2 to the ground pin and 450k to the input pin where if a type b is tested in the centre position it will read 250k to pin 1 and 3 from pin 2. and 500k from pin 1-3. Hope this helps.
Dave

[Simon Barden]

You won't get the full benefit of the shielding without sticking tape on the covers and creating your Faraday cage. I'd use copper if possible as dissimilar metals touching can react and corrode when damp. If you've got any other tape or film, then you could use it, but make sure that if it's overlapping, then it will need a conductive adhesive to get electrical continuity. Also, make sure it hasn't got any coating on it (just test it with a multimeter) as it will need to touch the copper round the lip of the cavity to get it's ground contact. If it's been coated in plastic to stop it oxidising, then it won't work.

You'll just have to check that none of the signal wires are touching the copper shielding, or an exposed shield wire isn't pulling against a potentiometer lug that's carrying a signal. The wiring looks OK in the photo but there are a couple of places where contact could be made if a wire got pulled in the wrong direction.

[Kick]

I'll have a look at that other metal tape but the wiring is my main concern right now.

I have been checking my photo with the wiring diagrams and everything looks ok to me too. So hopefully it is what you say Simon, some wiring touching something it shouldn't touch. I have a meeting with friends now so I'll have a look tomorrow

[Kick]

Quick question guys; I have just randomly used the potmeters for volume and tone but I have read in other topics that there are 'a' (for volume) and 'b' pots (for tone). Is this always the case? And could this be the reason why I have this problem with one volume and one tone knob?

[Kick]

No one?

Perhaps I'm not making myself clear enough. So again what I did; I followed the video tuts from PBG and there was no mention of different kinds of pots. So I just put in the four pots into the cardboard (as suggested by the video) and started following the steps of soldering.

But when done I tested it all and it appeared that only the bridge volume pot and the neck tone pot are working as expected. The bridge tone pot and the neck volume pot however are not working as expected. The bridge tone pot does nothing (turning the knob clockwise or counter clockwise) and the neck volume pot works as follows (when turning from zero to ten): full volume at zero, silence at five and full volume at ten.

When checking the soldering I noticed nothing wrong so I was very confused.

Later, I read some topics (and I really hate it that I don't know anymore who build is was) that someone had two pots labelled 'a' and two pots labbeled 'b'. The 'a' pots are for volume (as said) and the 'b' pots should be the tone pots.

Now I'm just wondering; could I have had the same pairs of pots and accidentally mixed up two pots?

Or, stated otherwise: does the LP kits comes with four identical pots?

[chrissyinbkk]

Hi Kick, someone on hear told me the A pot is the volume one, the B the tone, my first LP I did this and works wonderful

Albeit I have also read somewhere it doesn't matter a great deal... but I followed the advice and it worked for me..

[Andy40]

Hi kick,

the A and B refer to the resistive taper of the pot. For the volume pot you want an A taper it is smoother and doesn't drop off as quickly. That being said if you wired it correctly and got the A and B around the wrong way the circuit would still work, so no, that is not the source of your problem.

Is the wiring you have the same as on the other page? I cannot see where you have put an earth wire between the neck and bridge volume and you seem to have an earth between the neck and bridge tone? from the photo its difficult to check anything else

You can, of course check the tapering resistance of the pot that's not working with a multimeter