Old Ampeg Amp with a Tone King Attenuator

[spupilup]

I have a ‘68 Ampeg Reverbojet j12-r that I love. It puts out a very loud 18 watts of power. It’s a bit much for playing at home, especially with my pedalboard, and not disturbing the rest of the household. To remedy this I just bought and am awaiting delivery of a Tone King Ironman II mini attenuator.

The attenuator gets placed between the amp and the speaker. Unfortunately, this old Ampeg is wired straight from the board to its Jensen speaker. There are no 1/4” jacks to plug or unplug like you might find on a Fender. I’m wondering if there is any harm in snipping the speaker wire and soldering in about a foot more wire and a 1/4” male plug on either side? This way I can place the attenuator on top of the amp (or even on the floor) with the extra length of speaker wire I’ve soldered together. Amp to in and out to speaker, job done.

Any concerns with this method or any suggestions for a better way? The amp is all original so I don’t want to do anything that can’t easily be reversed. Thanks in advance for your opinions and suggestions

 

[NoTeleBob]

No worries. Unsolder the speaker wires. Solder a jack to the end of them, or a plug if they have enough slack to do what you want to location wise. or you can just solder some new wires to the existing speaker wires and extend that line. Use shrink wrap on the soldered connections.

Same thing in the other direction. Solder a longer wire to the speaker connectors and put a plug on the end to plug into the attenuator.

You can use common lamp cord, or round, official speaker cable for the extension. Either will work.

EDIT: Oh... and set up some kind of check procedure to make sure there's always a speaker load on the amp before you turn it on, every time. Don't want to kill a nice vintage amp.

 

[spupilup]

Thank you. I didn't really foresee any issues but wanted to check before doing any possible harm.
Cheers,
Paul

 

[spupilup]

I got the Tone King Ironman II and installed it between the amp and the speaker and cannot believe what a tremendous effect this attenuator has. Some may laugh but 18 watts can be painfully loud in the wrong circumstances. The attenuator really enables one to dial down the volume without losing the tone inherent in a naturally overdriven amp. I am really impressed with this unit and would recommend it to anyone in a similar situation where their combo is just too loud before you get to any nice breakup. Plus there are some great features on this attenuator such as a foot switch that boosts the signal when there's a need as well as a presence switch that really enables you to fiddle with compression and brightness. It really works nicely with my main overdrive pedal, the OE Custom RevivalDrive.

 

[Lowerleftcoast]

Any concerns with this method or any suggestions for a better way?

As @NoTeleBob wrote, the concern would be a *no load* on the amp if it happened to be switched to *on* without a speaker or load attached. You have mentioned 1/4 male plugs.

There are switch plugs available. Amphenol switchplug, and Neutrik silent switch are a couple on the market. Something like this would attach to the *amp out* cord.

 

[timfred]

Glad you like the attenuator. No problem with an in-line jack….except if it’s hanging free it can cause problems with strain, vibration, or sticking to the speaker magnet. I try to find some way to fasten them securely.

 

[slider313]

I install a small wood plate, with a shorting jack attached, to the wooden block under the output transformer. Early Ampegs all had theses "transformer support blocks". It's easy to do and the only thing you're left with is two small screw holes in that wooden block should you decide to go back to hard wiring it.

 

[Mowgli]

I install a small wood plate, with a shorting jack attached, to the wooden block under the output transformer. Early Ampegs all had theses "transformer support blocks". It's easy to do and the only thing you're left with is two small screw holes in that wooden block should you decide to go back to hard wiring it.


View attachment 999851

I did something similar with an Ampeg RRII; the output transformer was replaced with one that had 4,8 and 16 ohm wiring options. So I created a jackplate with 3 separate impedance output jacks and fastened the jackplate to the back panel of the cabinet.

Now, if I want to use a different speaker with an odd impedance I can. Just one speaker at a time.

The original speaker is loaded and is usually plugged into the 8 ohm output jack with a 1/4” low profile pancake male phono plug like Slider’s!

 

[KeithDavies 100]

I got the Tone King Ironman II and installed it between the amp and the speaker and cannot believe what a tremendous effect this attenuator has. Some may laugh but 18 watts can be painfully loud in the wrong circumstances. The attenuator really enables one to dial down the volume without losing the tone inherent in a naturally overdriven amp. I am really impressed with this unit and would recommend it to anyone in a similar situation where their combo is just too loud before you get to any nice breakup. Plus there are some great features on this attenuator such as a foot switch that boosts the signal when there's a need as well as a presence switch that really enables you to fiddle with compression and brightness. It really works nicely with my main overdrive pedal, the OE Custom RevivalDrive.

Thanks for this. I keep toying with getting some sort of attenuator. I got a cheap one a while ago and it seemed to make everything very noisy, so your comments here are really useful. Mine are predominantly heads, which makes it easier, but I have a lovely old Watkins Scout that, like yours, is just a bit too loud for clear conscience home use!