Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

volume pedal.. do i want 250k or 25k ?

Discussion in 'The Stomp Box' started by popthree, Oct 15, 2011.

  1. RomanS

    RomanS Poster Extraordinaire

    Jun 21, 2006
    Vienna, Austria

  2. jefrs

    jefrs Doctor of Teleocity

    Nov 20, 2007
    Newbury, England
    Typical OD pedal (Arion SOD-1)

    • Input Impedance - 300K ohms
    • Output Impedance - 10K ohms
    • Maximum Input Level - +5dB, 0dB = 1 V Effect Off
    • Maximum Output Level - -12dB, 0dB = 1 V Effect On
    So -
    High input impedance (suits output from pickups), similar impedance to front end of valve amp
    Low output impedance (will drive low impedance input or high impedance input)

    Input will accept low or medium level (less than "line") signal. A higher level won't damage it, but it doesn't sound nice.
    Output medium level (less than "line") i.e. the pedal is not really suited for the amp FX loop.

    This pedal is typical of most floor pedals. It might drive a 25k vol but would be happier driving 250k vol pedal. To drive a 25k one really requires a line-level signal ~1Vrms e.g. mixer (desk) or keyboards.
    Vol pedals are usually first in chain, or second in chain (do experiment), and then are 250k log or 500k linear. The 500k linear will give fine control at the top of its range and not load the pickups as much as the other one. The 250k log has its best fine control at the bottom of its range, from silence, and then rises rapidly in volume to full on, but it does load the pickups more.

    I have found that active vol pedals colour the sound whereas a passive one can be a tone-sucker as it loads the signal. Best to experiment with your pedal order.
     

  3. popthree

    popthree Poster Extraordinaire

    i didn't realize this was a can of worms topic
     

  4. 1300 E Valencia

    1300 E Valencia Tele-Afflicted

    Dec 13, 2010
    Fullerton CA
    Buy both, return the one that doesn't work in your setup.
    As we have learned today, class, you just gotta plug 'em in and try 'em out.
    Your Mileage Will Vary.
     

  5. fatsound77

    fatsound77 TDPRI Member

    32
    May 9, 2011
    usa
    To Fly.

    Ofcourse 250K is more versatile. No one said the contrary. But the the source driving the load is the determining factor. The standard average amp input is 1M. A 25K vs 250K in fron of this makes no difference until you determine the source signal that is driving the volume pot. In the OP case he is driving it with a low impedance signal, which makes the 25K the optimal match.

    By your philosophy of the following device being the determining factor will lead to nothing but total SUCK. Passive pups to 25K = huge tone loss into an OD or fuzz makes no difference, still suck. But passive pups into a compressor outputting a low impedance signal into 25K into any pedal let alone the amp... same signal, no suck and now controllable taper.

    There is two methods to proving this... Simply our friend ohms law with a pencil and paper, or simply plug these pedals in all orders and just get it simple. No can of worms, just a lot of wrong info. Low impedance = active. Two terms that relate to different situations, but mean the same thing.
     

  6. RomanS

    RomanS Poster Extraordinaire

    Jun 21, 2006
    Vienna, Austria

  7. fly135

    fly135 Tele-Holic

    597
    Dec 19, 2007
    Orlando
    If you notice I previously said only a brain dead monkey would put a low impedance input after a passive pup.

    "First of all if you have a passive pickup then there is no way the device following it will be a low impedance input. If that is the case then a brain dead monkey designed your board."

    I'm sorry but I know exactly what I'm talking about and I am well aware of how it applies. The passive is more versatile and putting it after active pup will not cause tone suck. I think you need to use ohms law to demonstrate how it can. And you will see that you can't. Get your pen and paper and support your claim.:idea:
     

  8. fatsound77

    fatsound77 TDPRI Member

    32
    May 9, 2011
    usa
    NO one said a 250K would suck tone after an active signal. Of course it wouldn't. The issue is the impedance imbalance results in a lowered taper pushing most of your volume throw to the last end of travel. It will work fine, but the OP wants to know which one will work best for him. Stop trolling the thread and going off tangent. The solution has been supplied to the OP's issue and you are in here stating incorrect advice let alone talking about things that weren't even mentioned.
     

  9. klasaine

    klasaine Poster Extraordinaire

    Nov 28, 2006
    NELA, Ca
    I've used a passive Goodrich 120 for 26 years both pre and post fx (comp on all the time) without any noticeable loss of tone or anything else negative. Studio and stage - zero issues.

    *My 120 finally gave up the ghost. I too now use a 'thru-tone' modded active EB vpjr. (Awesome!)
     

  10. RomanS

    RomanS Poster Extraordinaire

    Jun 21, 2006
    Vienna, Austria
    As I said, I use an active volume pedal (a George Dennis) myself - but I do also own a Boss FV500H (that's Boss passive high impedance vol. pedal, with a 250k pot, just like the Ernie Ball), and incidentially, I also own the Marshall ED-1 compressor (output impedance <1k - definitely low impdance!) that the original poster wants to use always-on in front of his volume pedal.

    So, to gather some real-life data, I just hooked those up with my Tele and my VHT Special 6 amp - and can indeed confirm that change in taper!

    If run:
    -) guitar->FX pedal->high Z vol. pedal->amp - the volume pedal has a very smooth taper, going seamlessly from off to full on over the full travel of the pedal (the Boss vol. pedal has an extra pot for setting a minimum volume, I turned that down all the way, so that the pedal travel really starts with no volume at all; and I turned down the compression on the ED-1 all the way, so the effect would not influence the results).

    If run:
    -) guitar->high Z vol. pedal->FX pedal->amp - there is no change in tone, BUT: there's a VERY noticeable change in the volume pedal's action/taper - there is almost no increase in volume for the first 50% of the pedal travel, and then there is a very sudden increase on the last part - it reacts more like an on-off switch, rather than a swell pedal...

    Unfortunately, I don't own a low impedance volume pedal for comparison purposes - but I can indeed confirm that a high Z type does change its taper (and quite a lot, more than I expected), if run following a low Z effects output - seems like both Boss and Ernie Ball do indeed know what they are talking about in their vol. pedal manuals/FAQs... :D
     
    Last edited: Oct 19, 2011

  11. Vizcaster

    Vizcaster Friend of Leo's

    Sep 15, 2007
    Glen Head, NY
    If you ever plan on possibly using the same volume pedal as an expression pedal for some other effects box or amp, then consider the requirements for that controller. For instance the Fender Cyber Deluxe has a certain impedance it wants to see from the volume pedal when used as an expression pedal (to control the wah, Leslie speed, and oh, yeah, volume). So check the specs on the multi-effects device to see what kind of volume pedal it wants to see when using it as an expression pedal. Otherwise I would expect the 250K EB pedal to be more common and more readily available used.

    Incidentally I have both the EB "Jr." and grownup pedals and the junior is way big enough for my hind paws; both operate very smoothly.
     

  12. fly135

    fly135 Tele-Holic

    597
    Dec 19, 2007
    Orlando
    My advice is correct and you cannot demonstrate with paper and pencil your claims. It is not trolling to correct someone who said stated a claim that is incorrect.

    I run a 250K EB pedal in a completely buffered circuit and have a fine sweep. Bottom line is that your claims are incorrect and cannot be substantiated by examining the circuit equations.
     

  13. klasaine

    klasaine Poster Extraordinaire

    Nov 28, 2006
    NELA, Ca
    I agree.
    This afternoon I had a quick session and I used my newly modded EB vpjr. in passive mode (thru-tone mod allows it to revert back to 'stock' if you don't use a 9v. pwr sply). Perfect opportunity to check out both my new vol. pdl. and hear if there's any difference where it's placed in a normal/standard guitar rig.
    I placed it in between a Fulltone 'fat boost' II and an Xotic 'EP booster'. when 'ON' they are indeed buffered. I noticed absolutely zero difference in the taper/sweep and response of my EB ... yes, I tried it straight into the amp too. In 26 years I never noticed anything weird with my Goodrich 120 no matter where I ran it and I almost always have something buffered.
    *The buffers in the fulltone and the xotic are excellent so ...

    I don't know what the 'math' says. My ears say no difference.
     

  14. tjalla

    tjalla Friend of Leo's

    Most interesting fly135, klasaine.

    I have had to correct a friends board who was running his guitar direct to a boss vol pedal. It sounded terrible this way, grainy and splatty as if there was a dying battery somewhere in line or a bad cable. Put a buffered tuner first in the chain, volume pedal after, and that solved that.

    So perhaps a low impedance vol pedal *must* see a buffered signal, but a 250k vol pedal can be place anywhere?
     

  15. klasaine

    klasaine Poster Extraordinaire

    Nov 28, 2006
    NELA, Ca
    Yes, if you're using normal, non-active pkups you definitely can't go straight into a Boss FV-500 L.
     

  16. fly135

    fly135 Tele-Holic

    597
    Dec 19, 2007
    Orlando
    For guitar applications a low impedance volume pedal is never needed in front of an amp. And is only needed when placed before a low impedance input like many amp FX returns. Many amps have a fx loop intended for rack FX which work with higher level signals and can drive a lower impedance FX return. These loops are not suitable for many guitar pedals mainly because the signal is too hot.

    In normal practice there will never be a pedal with a low impedance input in front of an amp. That's why the 250K pedal will always work. Which is contrary to some of the advice above.

    Of course you can put a device with low impedance input if you want to do something specific and know what you are doing. Even a 250K volume pedal can suck tone on passive pups. So it's still better to have an active buffer before the 250K volume pedal.

    I have my 250K EB volume pedal after several active pedals... Fish Chips EQ, Line 6 M5, and a Yamaha Magicstomp. My whole pedalboard is in an active circuit because it's in the loop of an RP1000. All of the above pedals are active and have a low impedance output. The sweep of the EB pedal is fine.
     

  17. popthree

    popthree Poster Extraordinaire

    I gotta go with what Romans and boss and eb are saying....I think that I'll be fine with the 25k in my setup ....I can always upgrade to the thru tone mod at a later time if I want to
     

  18. stratohiker

    stratohiker Tele-Meister

    317
    Jul 21, 2003
    Georgia
    I'd like to resurrect the post for my own selfish purposes ;)
    I recently had my older Goodrich pedal "rebuilt" (new pot, string, etc). Sent it off to get it done. It's a 120 model and I'm pretty sure they used the 500k pot that appears to be the standard Goodrich replacement these days.
    I've noticed that since I got it back and placed it back on my board (in the same place in line as always), that, the taper is such that the volume comes on very suddenly in the travel of the pedal.
    I'm guessing that there is some difference in the pot on the rebuild to cause this, as it appears that this only happens when it's on my board. Seems to be ok by itself into my little PR amp at home.
    Anyone have some input on this?

    Thanks
     

  19. fly135

    fly135 Tele-Holic

    597
    Dec 19, 2007
    Orlando
    Do you have an ohm meter? You can check the pot by ohming out the input cable with nothing attached to the output. If a higher impedance pot was used and you are plugging onto a circuit that has a low impedance it can cause the sweep to change like you described. Since nothing else changed it does appear that the pot is different.
     

  20. bonilsen

    bonilsen TDPRI Member

    Age:
    34
    3
    Apr 13, 2017
    Mandal, Norway
    This is what i got from Electronics Technician at Dunlop Manufacturing when asking about ohm issues when placing the passive 250k dvp4 mini volume pedal in the chain:

    Yes you can place the DVP4 after buffers and you can place it wherever you like in your effects chain. Impedance interactions are possible even if the DVP4 is placed first in line. To resolve an unwanted impedance interaction you may need to rearrange the pedal order so that the two interacting devices are no longer directly connected or you might try placing a buffer between the two interacting devices to correct the impedance mismatch.
     

IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.