Active to passive pickups advice on Pots.

the_great_huszar

I have an Epiphone Les Paul Prophecy plus currently fitted with active EMGs which I plan replace with Seymour Duncan AP2 to tame it down a bit. 

Now my question is, do I really need to replace the pots? Or can I leave them in for now and replace later?! 

Thanks in advance 

fretmeister

You REALLY need to change the pots at the same time.

The values are massively different.

ICBM

If you don't replace the pots, the passive pickups will sound like you're playing underwater.

the_great_huszar

Thanks for the replies, I had a feeling that was going to be the case, but I wanted to double check before soldering in the new pickups to find I need pots.

I'm thinking 500k CTS liner for both vol/tone and 0.022uf caps. Reading reviews I will have to open out the holes on the Epiphone as they are smaller than Gibson Les Paul's, makes me a little nervous drilling holes on finished surface! 

ICBM

You will need Log pots for the tones at least or they won't work properly - they will have all the sweep between 0 and 2 on the knob. Linear will work for volume if you don't want a fast drop-off from 10 down to 8.

Don't open out the holes with a drill, use a taper reamer. (Carefully, from both sides, until you can just get the pot through.)

normula1

You can now get CTS metric pots which shouldn't require the holes enlarging

the_great_huszar

ICBM said:

You will need Log pots for the tones at least or they won't work properly - they will have all the sweep between 0 and 2 on the knob. Linear will work for volume if you don't want a fast drop-off from 10 down to 8.

Don't open out the holes with a drill, use a taper reamer. (Carefully, from both sides, until you can just get the pot through.)

Interesting, thanks, I'll get 2 of each then. 

We must only be talking fraction of a millimetre between the metric and imperial. Great advice thank you.

normula1 said:

You can now get CTS metric pots which shouldn't require the holes enlarging

I shall definitely look for these first, if unsuccessful I'll get the the imperial size, many thanks.

ICBM

the_great_huszar said:

We must only be talking fraction of a millimetre between the metric and imperial.

No, it's 8mm vs 3/8" (9.5mm) - a real difference in size, rather than a metric/imperial equivalent issue. You definitely can't get US-size pots through far-east-size holes without substantial wood removal.

If you can get CTS in 8mm now and don't have a reamer, I would definitely look for those.

Alegree

Side note: if you're happy going without pots until you replace them, you could just bypass them completely.

the_great_huszar

ICBM said:

the_great_huszar said:

We must only be talking fraction of a millimetre between the metric and imperial.

No, it's 8mm vs 3/8" (9.5mm) - a real difference in size, rather than a metric/imperial equivalent issue. You definitely can't get US-size pots through far-east-size holes without substantial wood removal.

If you can get CTS in 8mm now and don't have a reamer, I would definitely look for those.

Whoa that is a huge difference lol! 

I do have a dremel type tool with a wide range of attachments. 

Quick browse on the net shows only a couple of places that do the metric one in the U.K. 

Alegree said:

Side note: if you're happy going without pots until you replace them, you could just bypass them completely.

I've near done that already with my Maverick, only have one pickup wired in, a Seymour Duncan JB in the bridge, via the vol pot. Everything else is just for show. Really made a huge difference with it.

normula1

I think I got mine from Axesrus
https://www.axesrus.co.uk/1-x-CTS-Pot-Split-Shaft-Metric-Size-p/cts59met.htm

the_great_huszar

normula1 said:

I think I got mine from Axesrus
https://www.axesrus.co.uk/1-x-CTS-Pot-Split-Shaft-Metric-Size-p/cts59met.htm

Yes I've seen those ones, first one that comes up in the google search. Thank you.

the_great_huszar

Right, the pots have arrived, ended up getting them from Axesrus, but they have put all 4 in one bag with no label. So which one is which?!? Numbers on the bottom are as follows..

A500 1614

B500 1523

Also arrived, new wiring cable, pair of 0.022uf orange drop caps. Just waiting for some copper tape to arrive, may as well shield it at the same time.

normula1

A = Log
B = Lin

the_great_huszar

normula1 said:

A = Log
B = Lin

Thank you! 

ICBM

the_great_huszar said:

Right, the pots have arrived, ended up getting them from Axesrus, but they have put all 4 in one bag with no label. So which one is which?!? Numbers on the bottom are as follows..

A500 1614

B500 1523

Also arrived, new wiring cable, pair of 0.022uf orange drop caps. Just waiting for some copper tape to arrive, may as well shield it at the same time.

Shielding… ah. Does it have a bridge/tailpiece ground wire? Quite a lot of guitars with EMGs don't, because they don't need it - but ones with passive pickups do. If you're lucky, there will be an unconnected wire sticking out of the woodwork on the side of the control cavity nearest the bridge. If there isn't, things get a bit tricky…

Sorry, I forgot that before.

the_great_huszar

ICBM said:

the_great_huszar said:

Right, the pots have arrived, ended up getting them from Axesrus, but they have put all 4 in one bag with no label. So which one is which?!? Numbers on the bottom are as follows..

A500 1614

B500 1523

Also arrived, new wiring cable, pair of 0.022uf orange drop caps. Just waiting for some copper tape to arrive, may as well shield it at the same time.

Shielding… ah. Does it have a bridge/tailpiece ground wire? Quite a lot of guitars with EMGs don't, because they don't need it - but ones with passive pickups do. If you're lucky, there will be an unconnected wire sticking out of the woodwork on the side of the control cavity nearest the bridge. If there isn't, things get a bit tricky…

Sorry, I forgot that before.

Just checked, There is a single black wire, coming out of its own hole towards the bridge. It is soldered to a tone pot. 

All the other wires run down more of a slot, obviously towards the pickups. 

ICBM

the_great_huszar said:

Just checked, There is a single black wire, coming out of its own hole towards the bridge. It is soldered to a tone pot.

Great! It's actually unusual that it's grounded, on a guitar with EMGs… but the important thing is that it's there.

So I won't be having to talk you through how to pull the tailpiece bushing out of the guitar using a crowbar .

the_great_huszar

ICBM said:

the_great_huszar said:

Just checked, There is a single black wire, coming out of its own hole towards the bridge. It is soldered to a tone pot.

Great! It's actually unusual that it's grounded, on a guitar with EMGs… but the important thing is that it's there.

So I won't be having to talk you through how to pull the tailpiece bushing out of the guitar using a crowbar .

 
Only a crowbar!  no screw driver to pry around the bush and ruin the top coat?!? Haha. 

In all seriousness, if it wasn't there I'd have bought a new guitar, even though I can't afford one.