Line level into Vintage effects? with enough output. How can I do this?

[rosssurf]

I have a question here and perhaps it is to ignorant to answer correctly. If so I appologize in advance  I want to run a line level from an old vintage keyboard signal into a few old phaser pedals from the 70's (Maestro phase/ps1a/1b and a Roland). It distorts if I run into these, If it is possible to attenuate the signal going into the phaser I probably won't get enough volume coming out.?..correct?..
The pedals will only be used for this purpose so any permanant mods are ok.

Is there a fix for this?

Does a Booster like the AMZ Mosfet booster boost enough to bring the sound back to line level. (  :icon_redface:admittedly , I am not real sure what "line Level' is)  So!, if i can figure out how to mod the pedals to take a line level signal would running  a booster afterwards to work to bring it back to "line level"?

[compuwade]

I would think that a buffer would probably fix the problem. I've had issues with certain pedals distorting with a select few devices plugged into them and a buffer has corrected the problem 100% of the time. I'm not sure if this is a perfect solution for your line level out, but it's worth a try since a buffer is probably the easiest thing to breadboard.

Good luck

[petemoore]

  You may not want to intrude into the keyboard for other reasons, or because that's where the dangerous high voltages are.
  Perhaps there's a smaller signal earlier on, the source may start out small, then is boosted to ''line level'' for the keyboard output.
  it's generally preferred to:
  Source>effect>boost>output
  Than:
  Source>boost>attenuate>effect>boost>output.
  It seems likely that a keyboard output already reasonably low impedance, and capable to drive a good cable / phaser input.

[Processaurus]

I would think that a buffer would probably fix the problem. I've had issues with certain pedals distorting with a select few devices plugged into them and a buffer has corrected the problem 100% of the time. I'm not sure if this is a perfect solution for your line level out, but it's worth a try since a buffer is probably the easiest thing to breadboard.

Good luck

I'll have to disagree, a buffer (an amplifier with a gain of 1) solves nothing in this case, where a signal is too high of an amplitude to fit within an effect's headroom range.  The original poster would want to attenuate the line level signal before the effects.  Passively would be fine, with a simple 10K trim pot set up as a volume control before the first effect.  Then an amplifying stage may be needed after the end to get it back up to line level, something opamp based like the MXR microamp would be the most transparent (though there are many beloved discrete boosters out there that impart their own character), especially if you used a charge pump IC like the MAX1044 to boost the power supply of the microamp, to keep the headroom high.

  the adjusticator at Geofex


max 1044 article

Microamp schematic

[punkin]

I wonder if someone could post typical values (level & impedance) for instrument, line and speaker signals?   

[caress]

i use all my pedals with keyboards, some vintage (polysix) some modern (nord stage) and the best thing i've come up with is to simply add a passive input volume control on most of my pedals - that way i'm not having to continually mess with the volume on the instrument to play nice with the pedals... i mainly use pedals that increase my volume, so that's not an issue, but i think what processaurus said is a good idea.

maybe you could build yourself a looper-type pedal with a passive volume control pre-send and a boost post-return.  that way you leave your phaser, chorus, etc on the whole time and you only need to switch one pedal on/off.  or simply leave the looper on all the time and switch the pedals on/off normally...  the bonus would be that you could use it with all your pedals that don't play well with keyboards.

[Strategy]

I'm primarily a keyboard player (synth/organ/rhodes/wurlitzer/modular synth/etc) and use all of my pedals with stuff. I use the old fashioned volume pedal- indispensable! Output levels vary keyboard to keyboard, so rather than modifying the other pedals I just keep a few volume pedals around. Also, you don't need to max out your output level on the synth. Synth levels are super high, organ levels can be pretty high depending on the make/model, wurlitzer piano tends to be pretty damn loud, rhodes quieter depending on the model. Keeping your synth output level it at 12 o'clock/50% is probably ample but quiet enough to not be overdriving everything that comes after it in the signal chain. Keep the headroom coming out of your synth output, then you can notch the volume up on your pedals or amplifier/mixer as needed.

There should be a "pedals for keyboards" thread. I play guitar and bass too, but I've spent years mixing and matching pedals to instruments with strange character like farfisa organ (most fuzzes amplify the background hum/noise floor inherent in all farfisas -- took me years to solve!) also little known combinations like rhodes and octavia -- who knew that would be so delicious?!?

- Strategy

[wavley]

I run keyboards into pedals all the time, I just turn them down a bit and it works great.  I ran a Yamaha CP-35 through my guitar rig last night for some recording and it worked great.

Volume pedals seem to be the way to go.

[T1bbles]

If you're outputting at line-level into pedals and it's distorting, simply stick an attenuator at the begining (EHX Signal Pad or make your own) and a boost at the end, most boost/pre-amp designs will boost well above line-level.

Line Level can simply be described as being 'pre-boosted' as it's primary purpose is to allow a signal to be directly inserted into a mixing desk without any extra gain (and extra noise) having to be applied to it. Meaning that you need to undo the boost with an attenuator, and add it in later, you might end up with a higher noise-floor this way, but at least you're not having to open up your vintage keyboard.

[rosssurf]

So It sounds like i could just use my AMZ mosfet boost after the effects to bring the level back up. But to lower the level going into the first pedal can I modify one of my other AMZ Mosfet boosts to "attenuate" the signal going into the effects pedals? Or is would modifying the AMZ be more work than making an attenuator?  Keep in mind I am not real sure what an attenuator circuit involves.

[petemoore]

  You could get rid of some of that power in a more frequency selective manner using a passive tonstack, depending on settings that might be enough, that and a volume control'd do it for sure, er maybe just +one more medium resistor

[John Lyons]

I'll have to disagree, a buffer (an amplifier with a gain of 1) solves nothing in this case, where a signal is too high of an amplitude to fit within an effect's headroom range.  The original poster would want to attenuate the line level signal before the effects.  Passively would be fine, with a simple 10K trim pot set up as a volume control before the first effect.  Then an amplifying stage may be needed after the end to get it back up to line level, something opamp based like the MXR microamp would be the most transparent (though there are many beloved discrete boosters out there that impart their own character), especially if you used a charge pump IC like the MAX1044 to boost the power supply of the microamp, to keep the headroom high.

  the adjusticator at Geofex
[/quote]

it's all right here.

[rosssurf]

John could I just put a 10k pot in a box before the first effect and use the AMZ at the end? He doesn't mind if the vintage effects are permananly modified, so should i just add a 10k pot into one of his pedals and make sure it is first in his chain?

10K Linear?, or Audio?

[petemoore]

  Audio trimpots are harder to find, maybe I didn't look enough.
  Set and forget, quality trimpot 10k - 100k range'd be my sight setter, that or just a fixed resistive divider [such as where I would set this discussions input pre-gain/attenuator pot].
  Use a pot to find the values which make the right drop in volume, measure between wiper and each outside lug resistances [keep 'em straight which is input which is Gnd.], leave fixed resistors setting the volume, not too hard a trick but just difficult to arrive and settle on a permanent setting..figure out if you're able to try whatever volume tricks you think you could get out of the keybaord w/pedals [that means reset sounds etc. on keyboard], set accordingly.
  You may want 2 settings, or even require an audio pot on the panel to match what comesoutta to what the pedals like to recieve, simpler is better if it's doing what's expected.