a question on theory not answered in FAQ

[effbiae]

hi,

thanks for the great forum...

in the end, i will probably just end up copying a design without thought as to how it operates... but i'd like to know how things work broadly speaking.

is it obvious that the output of an effect should have the same amplitude as the input to the effect?  i'd say it must be because it's common to piggyback pedals and if each of them amplified you'd end up with too much power going into the preamp.

are there any effects that need to be applied after preamp?

does anyone know if there is anything special about hooking in an effect to a rhodes EP?  my model has two jacks (output from pickups and input to preamp) and i assume you just hook an effect between these two jacks.

thanks for your help,


jack

[Mike Burgundy]

All effects and amps have inputs designed with a certain input level in mind. The amount you can push in there (or out of it) is often referred to as "headroom" - this is usually understood as the area between total silence and maximum output before clipping.
Most pedals are designed to have the possibility of unity gain (so input and output are just as loud), but also louder and softer - this is why some have master volume knobs.
If you stack a number of unity gain pedals you will end up with, you guessed it, unity gain. All these pedals will alter your sound, but not make it louder.
If you stack a number of more-than-unity gain pedals, you get louder with every step, and evetually you will reach a point where the next bit of circuitry runs out of headroom and will add (unwanted) distortion.
I think a Rhdes' PU's are practically the same as guitar PU's, so inserting guitar effects between them and the preamp should work just fine.
hih

[effbiae]

"headroom"
"unity gain"

some good search terms for me

I think a Rhdes' PU's are practically the same as guitar PU's, so inserting guitar effects between them and the preamp should work just fine.

i just confirmed that my rhodes has two "accessory" sockets (labelled 1 and 2). really they should be labelled "in" and "out" because they allow effects to put in series between the pickups and preamp.

[zjokka]

hooking in an effect to a rhodes EP?  my model has two jacks (output from pickups and input to preamp) and i assume you just hook an effect between these two jacks.

I believe you are referring to the Suitcase model Rhodes piano with built-in speakercabinet and amp. I think that exactly where these accessory sockets were designed for, but you can also use it to completely omit preamp, fx, amp and speaker and jack into an ordinary guitar amp.

If you don't care about the EQ and Vibrato, the piano will still work with a guitar or bass amp: run a 1/4" cable from the Accessory 1 jack on the front panel to the amp input, and you should get sound. If you have a 4-pin preamp without the Accessory jacks, you may need to remove the harp cover and run an RCA-to-1/4" cable direct from the pickup rail output to the amp
--->  fenderrhodes.com

Are you having problems hooking it up in the accessory chain?

ZJ

ps if you're interested, we're trying to get some diy dyno preamp stuff going here, but I still have to do my homework.

[effbiae]

Are you having problems hooking it up in the accessory chain?

i've plugged a microphone into socket 1 and that turns my rhodes into a soapbox.  i haven't built anything yet to plug into a loop

diy dyno preamp stuff going here, but I still have to do my homework.

nice!

what should i do if i want to pump line level into the amp?  i guess i need to hook into the output of the preamp by doing a small mod?


jack

[Ashurbanipal]

I have a wurlitzer 206. The preamp in it was useless, so I took the whole thing out and built the part of the circuit that supplies the electrostatic pickups with current. Then built a buffer circuit to run it through and then into effects I built mostly a treble booster and small stone copy and then into a guitar or keyboard amp. It sounds 100 times better without the stock preamp.

Your rhodes pre is probably better than the crappy wurlitzer ones, but that's my story.