high impendance volume pedal : more versatile?

[christoph h.]

Hi!

I want to buy a volume pedal and have searched the board for options. I learnt about the "impendance issue" and decided that I had to get a low impendance volume pedal.

But then I read (and saw) that some people (like guitarist Mike Landau) actually use high impedance pedals after other pedals.

Originally Posted by Other Forum

the High Impedance Volume pedal can work both ways but has a slight tone loss if used after a buffered pedal but i
guess you wont easily notice it on a live situation which is the way Mike uses it so it really woudnt matter.

I can imagine situations where I'll just want to use a passive bass and the volume pedal without other effects, Other times, an active bass or some effects might be in the chain.

So is a high impendance pedal the better choice for me?
Or should I get a low impedance version and simply add a "dummy" pedal (tuner, or something like that) in between, should the need arise?

What about additionally getting a buffer pedal to put in front of the volume pedal in "low impendance situations"?

Any suggestions for a buffer pedal? Axxess BS-2? Barge Concepts GLZ-1? Again, what works better, buffer converting high to low or variable buffer faking a passive signal?

The Barge DVB-2 looks very useful, but to be honest, I'm getting a little confused by thinking about all the back and forth conversions and trade-offs and blah.

In fact, the ease of use of only getting the high impendance version is very appealing to me, but I'm afraid od how big the tone loss will be...

[niftydog]

Ok, first up, that statement from the "other forum" is counter-intuitive to me. Provided all else stays the same (ie; cable capacitance) then a LOWER resistance volume pedal would have MORE high frequency loss.

What you should do is try out a low impedance volume pedal with your passive bass. If it works ok - go for it. If not, then you can start to worry about how to deal with it.

I'm inclined to think that a high impedance pedal run after effects might not have the "treadle action" you really want. For example, it might not have any attenuation until right near the heel-end of the treadle travel.

But the best way to work it all out is just go and try it out. You can't really pass judgement based on a bunch of opinions.

[christoph h.]

Thanks, that's very interesting, especially since in the other forum there's a comment about using a low impendance pedal in front of buffers, mentioning that it doesn't really work.

Originally Posted by Other Forum"

I use a 300L [Boss volume pedal] after 2 dist pedals and a chorus. It doesn`t work in front at all, but after the pedals I think it`s brilliant.

Has anyone tried this? I tend to think that a bit of high frequency loss might not be that bad, especially in a full band situtation...

Originally Posted by niftydog

Provided all else stays the same (ie; cable capacitance) then a LOWER resistance volume pedal would have MORE high frequency loss.

Do you mean in general or in situations where there's an impendance mismatch?

Maybe that's what they refer to in my above quote: a low resistance model will have unacceptable high end loss if not placed in the chain correctly while the high impendance version won't affect your sound that much.

[niftydog]

Originally Posted by christoph h.

Thanks, that's very interesting, especially since in the other forum there's a comment about using a low impendance pedal in front of buffers, mentioning that it doesn't really work.

It didn't work for that guy, but that really says nothing about whether the same set up would work for you and your equipment.

Originally Posted by christoph h.

Do you mean in general or in situations where there's an impendance mismatch?

It's not even so much to do with a mismatch. A volume pedal puts a resistance in parallel with the signal. Also, in mid-travel some resistance is in series with the signal. Depending on where you look in the circuit there's potential for parasitic low pass and high pass filters to be formed due to stray capacitance.

But because everyone's rig is different, there's just no good way of predicting what's going to happen. That's why I think you should just try some out with your equipment and work out what works for you.

[christoph h.]

OK. So maybe I'll just order both versions, try them side by side and then return one. Or try a low impendance version first, as you said.

Still, if you have the time, could you explain to me why there's no way of predicting the results? I thought that this impendance stuff is physics and therefore can be calculated, etc? Isn't the difference in what the volume pedal "sees" -> active/buffered vs. passive?
Which components of a rig make this unpredictable? Again, if you have the time I'd really appreciate an answer - I always try to understand what's going on with my equipment...

[niftydog]

The main problem is nobody really knows the impedance of their bass and no two basses are alike. Impedance is also a dynamic characteristic, meaning it changes with frequency. The same can be said about any impedance - such as those in volume pedals, effects pedals and other electronics.

So the reality is that just describing something as "low impedance" is effectively like describing the Earth as "a blob of dirt with water on it"! (A true impedance specification would actually be a graph of impedance vs frequency.) A result can be calculated, but the information needed to do that calculation just isn't available from the manufacturers.

So unless you know very detailed information about the pickups, the cables, the volume pedal and the electronics downstream, then it's impossible to know for sure what the result will be. Even if you did have that information it would be very complex and time consuming to come up with a theoretical result.

[christoph h.]

Thanks for the explanation! Off to the online shop, maybe I'm lucky and the first pedal will work!

[dubsymmetry]

hi, I had a 250k ernie ball jr. and it didn´t work well after effects or with the output of a mixer.
the problem wasn´t tone loss, but that most of the volume adjustment happened in the last 10% of the pedal sweep. there´s a knob to change the sweep in the pedal which made it a bit better, but there was still a volume jump in that last part of the sweep.

I changed it to the 25K version and the sweep is much better suited for my application - after effects or after a mixer.


just my experience.

[bassman515]

I noticed the same thing on my EB jr..did you jsut change out the pot? Was it easy to do?

Jeremy

[dubsymmetry]

Originally Posted by bassman515

I noticed the same thing on my EB jr..did you jsut change out the pot? Was it easy to do?

Jeremy

no, I was lucky and the shop where I bought it just changed the whole pedal out (I only had the jr. for 2 or 3 weeks; before I had a big ernie ball stereo/pan pedal, that´s now on ebay).

I think it might be possible without much hassle to change the pot, but the circuit is a little different since the 250k has a switch inside and the 25k doesn´t...

[niftydog]

Not only that, but the pot has a non-standard thread length from what I understand, making it hard for mere mortals to buy.

[dubsymmetry]

doesn´t ernie ball sell them as spare parts?

[niftydog]

So they do... USD$15 a piece.

[christoph h.]

An update: I recently tried an Boss FV-500H (=high impendance) and it works flawlessly
with a Sadowsky preamp and a Boss pedal (SD-1 modified by Stinkfoot) in front.
I also tried I passive bass run into it and I couldn't notice a difference.
But I only spent 5 minutes with each set up, doing some swells.

[bassman515]

I know that i can order one straight from EB, but i did not know if it was somthing that i could just switch out easily. I have had mine for a cpl years so i am sure that i cannot just do a switchout at the store...d'oh!

[dubsymmetry]

Originally Posted by bassman515

I know that i can order one straight from EB, but i did not know if it was somthing that i could just switch out easily. I have had mine for a cpl years so i am sure that i cannot just do a switchout at the store...d'oh!

I am not sure, but ernie ball might have customer support