Author Topic: Adding a Volume Control  (Read 1150 times)

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Offline Jeff Troy

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Adding a Volume Control
« on: December 13, 2019, 05:04:45 am »
Hi, Buds,

It's been a long time since I've been on the page. Went back on tour with Chubby Checker from 2015-2018 after some 50 years or so, and now busy with a 12-piece local swing band that's a lot of fun and a great diversion for a longtime rock player. Also been restoring and racing 60-year-old vintage race karts and working on my two VW-powered kit cars, and that doesn't cover all the RC airplanes I build and the contests I've entered with them.

Anyway, I'm back and I need a little help.

in 2010 or so I built for faux sunn floor monitors, you know, the slanted cabinet pairs that clip together, each with a 12" speaker and a small horn. My home-brews work just fine, but not all of my sunn mixers have seperate volume controls for mains and monitors. I built my floor monitors from memory and couldn't remember if the ones I had back in the '70s had volume controls (I used them with a Coliseum Audio Controller with individual volume controls).

Each of my monitor cabs has a 12" speaker and a small tweeter, and I would like to add a volume control to these cabinets. Can anyone tell me what to buy and how to wire it into the existing circuit? I need a control (pot or component?) that will mount on the inside of the baffle with the control knob or slider on the outside of the grill.

jefftroy at aol (period) com or seven-one-seven nine-one-seven 367 zero

BTW, I'm using a bunch of sunn gear with the swing band: 200s bass head with a 115SR cabinet (and my '69 Armstrong) for bass, sunn Stage Lead for my '74 Mustang, and a sunn Concert Controller I for PA with a pair of 412SR columns and sunn Concert Horn Accessories (all SM-58 mics). This is the PA head that I need the volume controls to support using the monitors effectively.

Also, if your want to see some fun pictures and hear some good ol' rock & roll vocals and bass work, check me out at  bandmix (period) com (forward slash) jefftroy  or just go to the bandmix site and search my name. The Sunshine track was recorded live in a club in 1980 with some of it going through the mixer at the back of the room.

Thanks in advance for your help and advice with the monitors.
759 New Holland Ave.
Lancaster PA 17602
C: 717-917-3670
www.bandmix.com/jefftroy
www.jefftroy.com (under construction)

Online loudthud

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Re: Adding a Volume Control
« Reply #1 on: December 13, 2019, 03:33:33 pm »
You didn't mention the power level, to following applies to 100W and below.

The common way to add a volume control to a speaker is to add an L-Pad (about $12 USD) between the amp and speaker. This is not a good solution because even if the L-Pad is rated at 100 Watts, it will usually burn up at 20W in a pro-audio environment. The other solution is a Constant Voltage transformer (about $35 USD) . A switch selects taps off of a transformer, usually in 3dB steps. These are available at

https://www.parts-express.com/

These days, even in small clubs, a powered floor monitor with it's own power amp(s) is the way to go.

Offline Jeff Troy

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Re: Adding a Volume Control
« Reply #2 on: December 14, 2019, 11:08:36 am »
Hi,Thud,

Long time! Thanks so much for the response.

Don't know the power rating for the concert controller 1, but I'm sure that it must exceed 20W. My XP2116 is rated at 200W without adding any slaves.

As you suggest, new, powered monitors are probably better, but in truth, replacing an entire sunn analog PA system with all new gear would probably also be better -- but it isn't what I have and it  wouldn't really be what I want vintage freaks to see on my stage. Guess that's my vanity going off again.

I looked at the CVT units you suggested at PE, but none are fitted with volume controls. I wouldn't know what to do with these, or how to install them to get the volume changing effect  needed. Could you please provide some additional instruction/direction?

Any idea what, if anything, was in the original sunn slanted floor monitor pairs? That might be the best solution.

Always thanks and warmest regards.
759 New Holland Ave.
Lancaster PA 17602
C: 717-917-3670
www.bandmix.com/jefftroy
www.jefftroy.com (under construction)

Online loudthud

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Re: Adding a Volume Control
« Reply #3 on: December 17, 2019, 04:09:41 am »
The one I was looking at, 242-874 at Parts Express doesn't work the way I thought it did. You need a 70V transformer in addition to the attenuator. You could use the type of attenuator designed to be used with a guitar amp, they can take the power but are quite expensive.

Offline Jeff Troy

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Re: Adding a Volume Control
« Reply #4 on: December 17, 2019, 10:41:16 am »
Thanks, Thud,

Much appreciated as always.

At this point, I think I'll leave them alone: one pair with the swing band as is, and the other pair with the 16CH mixer with separate controls.

Neither set is used enough to merit any excessive expense.

Thanks again, and it's nice to be back here with old sunn buddies again.

Warmest...
759 New Holland Ave.
Lancaster PA 17602
C: 717-917-3670
www.bandmix.com/jefftroy
www.jefftroy.com (under construction)