Author Topic: Simple volume control?  (Read 3028 times)

markr04

Simple volume control?
« on: June 08, 2005, 01:21:57 AM »
Hi. With all the boost and high-gain projects around, I can't believe I'm asking how to turn an amp down. I have a Peavey 5150 212 Combo all-tube amp which is insanely loud at even 0.5 on the volume pots. This amp doesn't have a master volume level like my other amps do. It's also one of the highest-gain amps on the market. So it's difficult to control and play quietly.

I'm not asking how to mod a 5150 - I've rebuilt it and been all up inside already. What I'm looking for is a volume-control project of some sort. An EQ pedal with the filters cut below 0dB was one suggestion I received elsewhere. Another was a volume pedal. Those are okay suggestions, but I don't want to waste a more useful pedal just for this purpose. A simple 1-knob-job would be do here. And a passive design would be the best for my plan. Would a passive design suck much tone or have any negative effects?

Thanks so much!!
Pardon my poor English. I'm American.

Basstyra

Simple volume control?
« Reply #1 on: June 08, 2005, 03:46:06 AM »
A volume pedal is a passive design, the simpliest way to turn volume down. Simple tension divider.

No tone loss if you put a good pot.

You could wire it right inside the amp ?
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markr04

Simple volume control?
« Reply #2 on: June 08, 2005, 10:34:37 AM »
A tension divider? Is that merely a pot? Will you please describe it more? Pot value, etc?
Pardon my poor English. I'm American.

Mark Hammer

Simple volume control?
« Reply #3 on: June 08, 2005, 10:52:33 AM »
Depending on how much you wantthe upper volume ranges to be accessible to you, you might consider replacing the volume pot with a much smaller value and a series resistor.  This will eliminate the "twitchiness" of the volume pot.

For instance, if the volume pot was, say 1M, you could replace it with a 250k pot and a 750k (or closest value) fixed resistor in series with the input to the pot.  This mimics a 1M pot that is *always* turned way down.  The advantage is that the entire rotation of thepotis now usable to adjust volume, rather than just the first 15 degrees or whatever.  That's why I say, it makes the pot less "twitchy".

Again, I have no idea how much of the volume pot's range you wantto use.  If you need to be able to dime the volume at some point, then obviously this won't work, but if you find yourself NEVER turning up beyond "5", then simply identify the resistance of the input leg of the pot at that volume level and replace it with a fixed resistor to complement the nearest usable value pot that will replace the ground leg.

Make sense?

The nice thing about this is that you can simply set the original pot to the side in a resealable bag and re-install it should you ever want to sell.  Meanwhile, the new pot plus series resistor can be easily installed.

vanhansen

Simple volume control?
« Reply #4 on: June 08, 2005, 11:13:17 AM »
Last I saw, the 5150 had a master volume. It's the "Rhythm Post" and "Lead Post".  Those are the master volume controls for each channel.

However, you make this box and put it in the effects loop, especially if the post control is touchy.  I know when I had the head version, the taper of the pots was terrible and it wouldn't go down to zero very smoothly.

http://www.erikhansen.net/diy/fxloopbox.htm
Erik

markr04

Simple volume control?
« Reply #5 on: June 08, 2005, 11:45:31 AM »
Vanhansen,

You're right, there are those two channel level controls. I'm comparing it to my XXL head, which has gain and volume controls on all channels (no gain on clean tho), and one master control just before the amp section. In addition to the poor attenuation at the post controls, unplugging a stomp box, etc. produces a pop that sends my dogs running for cover.


Mark,

Since Peavey uses proprietary pots, I can't easily replace the pot with another non-Peavey. I'm going to take your idea of the control being in the chassis and Vanhansen's schematic and marry the two in amplifier matrimony.

Thank you both!!
Mark
Pardon my poor English. I'm American.

vanhansen

Simple volume control?
« Reply #6 on: June 08, 2005, 11:49:09 AM »
Quote from: markr04
Vanhansen,

You're right, there are those two channel level controls. I'm comparing it to my XXL head, which has gain and volume controls on all channels (no gain on clean tho), and one master control just before the amp section. In addition to the poor attenuation at the post controls, unplugging a stomp box, etc. produces a pop that sends my dogs running for cover.


Mark,

Since Peavey uses proprietary pots, I can't easily replace the pot with another non-Peavey. I'm going to take your idea of the control being in the chassis and Vanhansen's schematic and marry the two in amplifier matrimony.

Thank you both!!
Mark


Ahh, so the XXL has a "master" after the 2 channel masters.  Interesting.  Never saw that before.  I've owned 4 Peavey amps in the past and every single one of them had that pop, 2 Bandits, 1 Triumph head and the 5150 head.  The 5150 head wasn't as bad but the others 3 were.

I use the volume box in the loop of my Marshall and it's perfect for what it does.  Good luck with it.
Erik