Anyone ever build/buy a multi-input selector to "A/B" different instruments/pickups.

[Bryan Jeppson]

What I'm looking for is a way to have 4 (or more) different guitars (or basses) plugged in to a box that subsequently has one output going to an amp. I want to be able to show potential customers the tonal differences between several instruments without having to go through the clumsy routine of muting the volume, unplugging gtr1, plugging in gtr2,turning the amp volume back on,etc. I would think all I would need would be 5 input jacks drilled into one side of an electrical box and one jack on the other side with a rotary switch tying everything together? Should I solder all the grounds together and ground them to the box and just have the hot connections soldered to the switch?

[David Schwab]

I'd solder the grounds together, and ground the box, and then have the hots go to the switch. You don't want to disconnect a ground when switching.

I did something like this once to test out potentiometer values.

[Mike Sulzer]

But you still are going to have to adjust volumes, and you cannot do that on your box and have it sound the same as plugging directly into the amp. If your demos are dirty, it is not so simple at all since multiple controls need to be adjusted to get the best sound from each instrument.

What I'm looking for is a way to have 4 (or more) different guitars (or basses) plugged in to a box that subsequently has one output going to an amp. I want to be able to show potential customers the tonal differences between several instruments without having to go through the clumsy routine of muting the volume, unplugging gtr1, plugging in gtr2,turning the amp volume back on,etc. I would think all I would need would be 5 input jacks drilled into one side of an electrical box and one jack on the other side with a rotary switch tying everything together? Should I solder all the grounds together and ground them to the box and just have the hot connections soldered to the switch?

[Steve Conner]

Well then, you need 4 of the same amp so you can set each one up for its respective instrument!

If you want to sell a particular guitar, turn its amp up a bit louder.

Having said that, I don't think the A/B box would be a completely useless endeavour. For instance take the fact that a humbucker guitar has higher output and overdrives the amp more than a single-coil one. That's a valid tonal difference, and why wouldn't you want to demonstrate it?

[Chuck H]

One note... It would probably be a rotory switch and it doesn't need much in the way of rating to do the job. That being the case it's eminently more possible to get a "make before break" switch. That will help minimise switching noise and help to make the whole presentation process look more professional

[Mike Sulzer]

Four amps, good idea! Maybe a bit expensive.

humbucker, valid tonal difference: Unless you are in the "always turn everything up all the way" school, the lower output level of the SC might not be so important. Under certain circumstances the humbucker might offer less flexibility if it significantly overloads the first stage. High gain amps do not always provide sufficient adjustability. For example, at least three level controls are better than two.

Well then, you need 4 of the same amp so you can set each one up for its respective instrument!

If you want to sell a particular guitar, turn its amp up a bit louder.

Having said that, I don't think the A/B box would be a completely useless endeavour. For instance take the fact that a humbucker guitar has higher output and overdrives the amp more than a single-coil one. That's a valid tonal difference, and why wouldn't you want to demonstrate it?

[David Schwab]

I disagree about getting all the pickups the same volume. How would you know which pickup is louder, or cleaner than another? Which one breaks up sooner, etc.?

You want the same amp set the same way, and then you can get an idea how each pickup would work with those settings. If you compensate the volume, then the buyer might get the pickup home just to realize it's output is too low or hotter than he wanted. We already know a single coil is usually not as loud as a humbucker. Why make it seem so?

To compare them with each other you need a reference point.

[Chuck H]

+1

[Stealth]

A box like a Behringer MX400 sounds like it'd do the job. Four come in, one (or more) come out, depending on the set volume on the MX itself, and if you really want to, you can even out the volumes on it.

[Mike Sulzer]

Actually, what I am saying is that you have to adjust for the best sound and that implies differences in several knobs. However, Steve makes a good point about louder things tending to sound better. Get your favorite retired stereo salesman drunk and see what he says.

The simple ABCD box is fine for comparing different variations of the same basic design, of course. And it is good for a broader range of differences if the playing is clean, such as a lot of bass playing. But if you have multiple strong non-linear responses, then starting with a different level at the pickup makes differences that require adjustment for the best sound. There is no right single setting for comparison.

And of course the answer to your questions is: once you get the best sound, start by looking at the settings of the knobs. Then if you want to know the exact pickup level differences, use the same settings for both (or all) on the clean channel.

I disagree about getting all the pickups the same volume. How would you know which pickup is louder, or cleaner than another? Which one breaks up sooner, etc.?

You want the same amp set the same way, and then you can get an idea how each pickup would work with those settings. If you compensate the volume, then the buyer might get the pickup home just to realize it's output is too low or hotter than he wanted. We already know a single coil is usually not as loud as a humbucker. Why make it seem so?

To compare them with each other you need a reference point.

[big_teee]

Actually, what I am saying is that you have to adjust for the best sound and that implies differences in several knobs. However, Steve makes a good point about louder things tending to sound better. Get your favorite retired stereo salesman drunk and see what he says.

The simple ABCD box is fine for comparing different variations of the same basic design, of course. And it is good for a broader range of differences if the playing is clean, such as a lot of bass playing. But if you have multiple strong non-linear responses, then starting with a different level at the pickup makes differences that require adjustment for the best sound. There is no right single setting for comparison.

And of course the answer to your questions is: once you get the best sound, start by looking at the settings of the knobs. Then if you want to know the exact pickup level differences, use the same settings for both (or all) on the clean channel.

I agree.
If you are going to compare 4 different neck Humbuckers, or 4 different bridge humbucker.
Compare 4 different strat single coils that are similar.
The only problem I see is that all guitar sound different.
I can put a pickup in this guitar and it sounds like Heaven.
I can take it out and put in an Identical guitar, and Maybe not so great!
David has the right idea.
The only way to realistically compare is to use one guitar and record the results.
But the A,B,C, & D will give you a pretty good Idea with similar products.
Good Luck,
T

[David Schwab]

However, Steve makes a good point about louder things tending to sound better.

While that's true, that's implying that a louder pickup will sound just like a lower output pickup. Thats not the case however.

So, if you wanted to hear the difference between a Filter'tron and a Duncan JB, you want the amp to stay the same. You will immediately hear the JB is many times louder and darker and breaks up the amp at the same settings that the 'tron was clean. That's why they make over wound pickups.

After that you can tweak the amp to get a tone that you like. But if you are just A/B'ing pickups, you have to start with everything normalized. Otherwise you can tweak the amp to make a lipstick tube sound like a DiMarzio Super Distortion, and what good is that?

When I test my own new guitar pickup designs I start with the amp (in my case an amp sim) set exactly the same way all the time. That's my starting point. It's a clean Twin patch. Then I can see how it works overdriven or whatever. But I want to hear the pickup in that initial state. You want to hear the pickup, not the amp.

[Mike Sulzer]

Sure, I can see what you are saying as a pickup designer, although there was no implication that louder and softer pickups sound alike, just that louder sounds have an advantage over softer ones.

But BJ wants something to help his customers determine the best pickup for them. Customers come at all levels of expertise as guitarists, but I think most are aware that you have to adjust the amp to get the sound you want with the guitar you are playing. Certainly the customers you really want are.

While that's true, that's implying that a louder pickup will sound just like a lower output pickup. Thats not the case however.

So, if you wanted to hear the difference between a Filter'tron and a Duncan JB, you want the amp to stay the same. You will immediately hear the JB is many times louder and darker and breaks up the amp at the same settings that the 'tron was clean. That's why they make over wound pickups.

After that you can tweak the amp to get a tone that you like. But if you are just A/B'ing pickups, you have to start with everything normalized. Otherwise you can tweak the amp to make a lipstick tube sound like a DiMarzio Super Distortion, and what good is that?

When I test my own new guitar pickup designs I start with the amp (in my case an amp sim) set exactly the same way all the time. That's my starting point. It's a clean Twin patch. Then I can see how it works overdriven or whatever. But I want to hear the pickup in that initial state. You want to hear the pickup, not the amp.

[Mike Sulzer]

It is amazing how different some "identical" things are!

I agree.
If you are going to compare 4 different neck Humbuckers, or 4 different bridge humbucker.
Compare 4 different strat single coils that are similar.
The only problem I see is that all guitar sound different.
I can put a pickup in this guitar and it sounds like Heaven.
I can take it out and put in an Identical guitar, and Maybe not so great!
David has the right idea.
The only way to realistically compare is to use one guitar and record the results.
But the A,B,C, & D will give you a pretty good Idea with similar products.
Good Luck,
T

[ken]

I built one once when I ran my own store. It had four footswitches, and the customer could choose one of three of my guitars to test and plug in his own guitar into the fourth switch. It worked great for pickup demos, and lasted about a week... until someone stole it.

ken