Tone sucking volume pedal

Rick Garrett · From: Tyler, Texas

I've been using a Goorich L120 volume pedal with my super slide. I've noticed a little bit of distortion that I simply could not get away from. So I took the volume pedal out of the loop and sure enough crystal clear and clean tone. Then I thought I'd try the VP again after a couple of weeks without it. Still slight distortion but I've got one of those Canadian pots coming so that should fix the problem BUT, even beyond the sound of the distortion I can tell that the tone is not nearly as fine with the volume pedal vesus without it. After going a couple of weeks without the VP and then plugging it in there was a major difference in the overall tone of my playing. Way better without a pedal.

Do volume pedals always effect the tone we're after?

Rick

John Daugherty · From: Rolla, Missouri, USA

Rick, that is the reason so many of us use the Hilton Pedal. I suggest you try one and hear what it does.

------------------
www.home.earthlink.net/~johnd37

Jim Peters · From: St. Louis, Missouri, USA, R.I.P.

Put a tube screamer or other buffered effects pedal in front of your v-pedal,or a black box. If you have a NV112, use the 3 chord method of hookup. JP

Joey Ace · From: Hamilton, Ontario, Canada

All pot pedals will have an effect on your tone, because you are introducing a resistor between your guitar and amp.

The effect is usually not distorton, but a roll-off of treble at different positions of the volume pedal.

I use a Hilton for this reason. Goodrich also make a potless pedal. If your amp has the required jacks, a three cord hook up will also solve this problem.

Mike Brown has posted a good article about the the three cord hookup here: http://steelguitarforum.com/Forum11/HTML/002639.html

[This message was edited by Joey Ace on 24 February 2006 at 05:42 AM.]

Rick Garrett · From: Tyler, Texas

Thanks for the replies fellows. You know its odd but I don't think I'm missing the volume pedal. I seem to be compensating by using my pick attack to control the volume level I want. Gee I wonder if that's a good thing?

Rick

Jon Light (deceased) · From: Saugerties, NY

I was trying some new electronics on a gig--a couple of stomp boxes I wanted to audition on a bandstand too small for my pedalboard so the wiring hookup was sort of a pain. As I was warming up for a couple of minutes everything sounded decent and ready to go. Then just shortly before we started our set I realized that I had totally failed to hook up the VP--I had gone straight from the steel to the effects to the amp. And I had been warming up with my foot on the VP and totally convinced that it was working as normal.
I'm still not sure what the moral of the story is but it has gotten me thinking about how I use the pedal (which I have no intention of ditching) and things like touch and control in my picking hand.

BTW--I'm puzzled about what would cause distortion in a passive VP. Crackling during movement is a common indication of a bad pot but if the pedal is stationary I can only think of intermittent contact being an issue. I would consider making sure that the in & out jacks are clean--a q-tip with alcohol and some vigorous in/out excercise with a plug would help that.

Kevin Hatton · From: Buffalo, N.Y.

Good suggestion Jon. It sounds like a solder problem in the pedal more than the pot. I also use an RV-3 in the chain to buffer the signal on my Goodrich. I use George L cables. My signal is crystal clear without any tone loss. Having an effects device in the chain really makes a big difference.

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

The topic of impedance loading, which can cause a general dulling of sound, is discussed at length in this recent thread:
http://steelguitarforum.com/Forum11/HTML/007805.html

There is nothing, per se, wrong with a pot pedal which has a good, clean pot. The distortion you mention is not normal, but it could be a number of things, including a bad solder joint, problem with the jacks or pot, or corrosion at a mechanical contact point, as has been suggested.

But if you use a high-impedance pickup (say around 20 KOhm DC resistance, as is typical on a steel), plus a 500 KOhm volume pedal like a Goodrich 120 directly into a fairly low-impedance input (an example would be some of the Peavey solid-state amps, which have high-input impedance of 220 KOhms), then you can lose some high end, even when you get your volume pedal in order. The reason is that voltage transfer from the source (pickup) to amp depends on the ratio of source impedance to effective input impedance of the pot/amp combination you're using. With a 500K volume pot full-on, that effective DC resistance is less than 200 KOhm, and less when the pedal is backed off. The ratio of output-to-input impedance is less than 10-1, which means that you lose something like 10% of the output voltage of the pickup across the pickup impedance load. That, by itself, is not a big deal. The real problem is that the impedance of a typical pickup is highly inductive, due the the coil and magnet. Inductive impedance goes up with frequency, so the typical pickup impedance function goes up sharply from 20KOhm at high frequencies. There is also the effect of winding capacitance, which counterbalances this at some point. These effects are very pickup dependent. But overall, the critical impedance ratio is usually even smaller at high frequencies, and thus one loses more high frequency content than low frequency content. This is what makes the sound "dull".

The solution is to either

1) Put a buffer - any device with a high input impedance and low output impedance - between the pickup and the amp. Again, this has already been suggested. Brad Sarno's Black Box and Revelation preamp now feature a variable impedance control, an excellent addition, IMO.

2) Use an active volume pedal like a Hilton, which also acts as a buffer.

3) Use a much higher-impedance amp - the Twin Reverb and Steel King amps, for example, have 1 MegOhm input impedance.

4) Leave it alone if you like the less bright sound.

Cliff Kane · From: the late great golden state

It may also have to do with how far the pedal is turning the shaft of the pot. Sometimes to set the pedal so that it completely shuts down the signal in the heel down position, the pot will not be completely open when the pedal is in the toe down position (does this make sense?). Consequently, the pot is still turned down a bit when the pedal is in the wide-open position, which will increase the effect of the pot rolling of the high end. If you recalibrate the string and the pot shaft so that the pedal turns the pot completely open this may help, but then you may have a pedal that doesn't completely cut-off the signal when in the heel down position.

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Dave - Are you saying that a "matchbox" is not as important with the Fender Steel King? It wouldn't hurt my feelings to remove one item in the chain.

------------------
Lee, from South Texas
Down On The Rio Grande

Mullen U-12, Evans FET-500, Fender Steel King

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

Lee - for me, yes. I don't need any buffer whatsoever with a Goodrich 120 into my 1-MegOhm input impedance Dual Showman Reverb, that's for sure. It gets plenty of sizzle with the bright switch defeated and Treble/Mid/Bass set at 5/5/4 respectively, with a 17KOhm wound Truetone using John Olynyk's old black Zum U12. If I increase the treble or enable the bright switch, I can peel paint at 50 yards.

But you may feel differently. Try removing it and see what it sounds like. I try to let my ears always be the final judge - theory and tech solutions are just a means to an end. I don't use a Matchbox, but that also acts as a variable-gain active preamp, does it not? You may need it for that reason - I can't say for sure.

Ronald Bear · From: Newark, Ohio, USA

If you have a Peavey amp use the 3 wire
hookup. Problem Solved.

Larry Strawn · From: Golden Valley, Arizona, R.I.P.

As I stated in another post I just ordered a Hilton pedal. Is it advisable to still use the 3 cord [pedal patch] with this pedal, and to continue running my E/F through a separate E/F loop on my Sessions 400?

Larry

[This message was edited by Larry Strawn on 28 February 2006 at 07:37 AM.]

Donny Hinson · From: Glen Burnie, Md. U.S.A.

It's not the pot that robs highs, but the high-impedance pickups that most steelplayers like to use. If pots, in themselves, robbed you of highs, then every Telecaster made would come off as being delinquent in highs, since they all have pots in them.

Has anyone here ever heard a Tele with poor highs?

I rest my case.

Jim Bates · From: Alvin, Texas, USA

You can try a simple hi-pass filter, which for this case is just a small disk capacitor (try 100, 220 or 300 mmf) soldered across the input jack center lead and the output jack center lead of the foot volume pedal. A radio man showed me this trick many years ago to stop the loss of so many high frequencies from ANY pot, whether foot volume or volume control on the guitar.

The capacitors are cheap and this is a simple mod to make.

Try the experiment: set the volume pedal a half on, then try each of the sizes of caps until you find which just 'brightens' the tone.

I have used this mod for 35+ years on all of my foot volume pedals.

It works!

Thanx,
Jim

Steve Zinno · From: Spring City, Pennsylvania, USA

Jim B, thanks for a good tip. I've done something similar with my guitars for 20 years but never tried it across the jacks in the VP. Should be a nice experiment.

------------------
steve z.

Donny Hinson · From: Glen Burnie, Md. U.S.A.

The high-pass filter Jim's referring to has a similar function as an amps "bright switch". It's true that pots rob a little of the highs, but so does coax cable, so does everything in the signal chain. The question to keep in mind is "Will turning up the highs on the amp replace the highs lost when you have into these losses?" In most all cases, the answer is yes! I can't tell you how many times a player has said to me "My amp doesn't have enough highs", or "My amp doesn't have a nice full sound". When I look at their amp, the answer to their problems is apparent. They have the highs on 3 or the bass on 4. If you don't use all the capabilities of your amp, you'll wind buying device after device to improve your sound when the real problem is that you're afraid to adjust the amp, or haven't experimented with all it's capabilities. I've heard a lot of guys say "I never turn my amp's volume over 3. If that's the case, then they've never heard the real (and probably "best") sound that amp's capable of! Just like a car engine, an amp has to reach a certain power output to be efficient and work it's best. Turn the amp up, and then learn to regulate the volume with your foot pedal (that's what it's there for.)

And before you go out and buy something because "It just doesn't sound right", make sure you've twisted all the knobs first!

Jim Bates · From: Alvin, Texas, USA

FYI, I use only the Belden 9272, two conductor, plus woven shield (blue cable). After finding high frequency losses in almost all of the commercial guitar cords at the time (early 70 to mid 70's), this cable has very low capacitance, and no high freq loss that I can hear. I'm sure there are very good low-capacitance cables on today's market, also.

Thanx,
Jim

Forum Index > Electronics		Next oldest topic :: Next newest topic