Feb 21

Speaker-Out Mod for SS Vypyrs

Three Approaches to external speaker connections

Many combination guitar amplifiers (amplifier and speaker in one box) do not provide a speaker output jack to allow connecting the amplifier to an external speaker.  Strangely enough, it seems that everyone who owns a combination guitar amp wants to know what their amp would sound like if it were driving a stack of a half dozen 12″ speakers.  This blog describes and illustrates three different approaches for connecting a combination amplifier to an external speaker.  All three approaches are relatively simple to implement and differ in term of their ease of use after completion and their degree of permanence (do you really want to affect the value of your amplifier?).

Traditionally, guitar amplifiers are connected to external speakers using 1/4″ phono jacks and speaker cable (looks like an instrument cable but with a heavier guage of wire inside).  If you want to use a friend’s speaker cabinet to try out the sound of your amplifier with a different cabinet you probably don’t want to show up with wire clippers and a soldering iron in your hands.  He will probably find an excuse as to why he can’t participate in your experiment right now, and could you come back later.

Modified Vypyr 15

Modified Vypyr 15

If you expect someone else to give you access to their speaker cabinet, the connection needs to be something that they will be absoultely comfortable with when they see how you are going to perform your little test.  Having anplug-in that looks familiar to them will go a long way towards relieving their uncertanty about your approach.  There are also some issues of asthetics and personal craftsmanship that should enter into how you do this as well.

Speaker Wire Extension

The first approach is a simple wiring connection solution suggested to my by WT on the Peavy Vypyr forum.  This involves connecting some male quick connects to a 1/4″ phone jack.  To connect this rig to an external cabinet the quick connect spades on connected to your internal speaker are unplugged and plugged into the cable built in the project.  Then, the speaker cable to the cabinet that you are testing on in plugged into the plug on the other end of the cable.

Parts List

  • Radio Shack 274-340  1/4″ Mono Phone Jack
    Wrong Part



    • Don’t use this one – not hefty enough
  • Radio Shack 64-3049 Quick Disconnects
    • wrong part – too wide
  • 4″ of 18 Guage or better speaker wire


I normally try to come up with parts lists for projects that have as many components from Radio Shack as possible.  Not because I believe that they are the best parts or that they are the best proced.  Rather, there is almost always a radio shack nearby (at least in the States) and they are dependably open on the weekends when people have time to do little projects like this.  Unfortunately, the two common parts from Radio Shack that would seem to work for this project are unsuitable.  First, the quick connect spades are an automobile part.  They are too wide and too thick for connecting the wires from your amplifier to.  To find the right sized quick connects required a trip to a local electronics parts store.  Pretty inconvenient (and the reason I try to recommend Radio Shack parts) but the right part makes the difference between a good working project and a disaster.  The Radio Shack 1/4 inch jack is also unsuitable for this usage.  If you look at the attached picture you might get some idea of how light-duty it is.  This jack would work wonderfully for line-level connections, but it does not withstand soldering the heavier guage wire that we need for driving a 75 Watt speaker.  Heavier duty jacks were available at the local music store.  These were able to withstand hot soldering to heavy guage wire without melting and falling apart on the workbench.

Quarter Inch Phone Jack

Quarter Inch Phone Jack

Carefully solder the speaker wire to the 1/4 inch phone jack.  Be careful to ensure that the point where the wires are soldered to the jack will clear the connector barrel when a plug is inserted into the jack. 

Tinning the wires before getting started is a smart move.  Not doing this will result in a connection that is undependable and may cause problems.  You should also note that connectors like the one I am using in the illustration have a small plastic sleve that comes inside the barrel.  This is not packing material.  Rather it is an insulator that you will want to make sure gets back into the plug when it is reassembled.

Completed Cable

Completed Cable

The quick connects are usually just crimped onto the other end of the wire.  You may want to find insulated ones (as shown in the illustration) to prevent accidental shorting of the wires against each other or anything else that might be in the area.

To use the connection cable, the quick connects are disconnected from your Vypyr’s speakers and plugged into the male quick connects on the wire.  You can then use a standard 1/4 Inch speaker cable to connect your Vypyr to any external speaker setup.  Note that Vypyr 15s have a 4 Ohm output while the others have an 8 Ohm output.  You should be safe connecting to a speaker with a higher impedance, but connecting to one with a lower impedence sould damage the amplifier.

A More Permanent Approach

OK, So you have used a rig like the one above to test your Vypyr on a big cabinet and learned just how incredible these things can sound. (still working on option 2)


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  1. RY

    I was wondering how this would be achieved with a 2×12 vypyr? I own the vypyr tube 120 and need an attenuator to take advantage of the tube tones at “bedroom” level requiring me to make a modification like this, however I only see people with mods for just one speaker so I’m lost as to what I should do.

    1. Glen

      Ry – There are only two properties that the amplifier output is concerned with. These are the resistance (ohms) and the current handling capacity (Watts) of the speakers. It dosen’t make any difference if you are connecting one speaker or one hundred. So long as the impedence and the power handling capacity are there this will work.

      I’m a little concerned about your approach to volume reduction though. The ‘tube tones’ that you are talking about are a result of the speaker transformer being driven way past its design capacity. You bought a 120 and it has a speaker transformer that won’t over saturate until you over-drive it. Smaller speakers aren’t going to magically make the transformer less efficient. The whole purpose for the Power Sponge is to do just what you are talking about without having to modify the amplifier circuitry (or change the speakers).

      Doesn’t the 120 already have speaker out jacks on the back?

  2. Rex Ryan

    This web site is really a walk-through for all of the info you wanted about this and didn’t know who to ask. Glimpse here, and you’ll definitely discover it.

  3. Emmanuel Alexis

    Wow, very simple and easy to do speaker-out mod.

    So basically you have to unplug the wires from the amp speaker and then connect them to this thing. Any downsides?

    Thx in advance and keep up the good work 😀

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