News:

Forum may be experiencing issues.

Main Menu

How much gain can my amp take?

Started by satchmo1991, September 05, 2024, 01:33:47 AM

Previous topic - Next topic

satchmo1991

I am still learning about op-amps, and while I think I have a decent grasp on how to use them, I am concerned with the amount of gain they are capable of producing. I have some TL072s that I wanna mess around with, but I don't want to send 8+ volts to my amplifier. Is there a good rule of thumb or something when it comes to pedal building with regards to how much your circuit should output? I've tried looking for my amp's input voltage specs, but everything I find is about the supply voltage, not the signal voltage. Maybe I am missing something obvious. Thank you guys! Pic is just an example of a hard-clipping dual op-amp circuit I wanna breadboard when I thought to ask this question.

jwin615

1)don't know what amp you are using
A tube amp *can* respond well to boosted signals. A SS amp will at best, saturate the input stage and sound like trash.
2)
A)you're not going to get a good sounding signal at 8v p-p out of an opamp operating at 9v if a boost is what you are after.
B) if you like the sound of a opamp shitting itself, use a voltage divider after.
---
I have one pedal I built that outputs 2.2v p-p at full tilt. Sounds great on a tube amp.
I would consider that a Very hot pedal and it really pushes the preamp stage.
8v p-p output won't really be usable because, if the amp even handles it, your volume will increase a lot! Good way to get kicked out of a band if you keep trying that. It also won't play well with any other pedal after it.

250mV to 1V p-p is a good range, depending on the pedal. I don't measure a lot of outputs, maybe Brian can chime in and give you a more refined range but I can say, 8v isn't in that range.

satchmo1991

Quote from: jwin615 on September 06, 2024, 04:09:16 PM1)don't know what amp you are using
A tube amp *can* respond well to boosted signals. A SS amp will at best, saturate the input stage and sound like trash.

Sorry, I meant to include that. I have a bunch of different amps, but the one I was checking on is the Fender Mustang III. I couldn't find anything about input voltage in the manual. Regardless, I am mostly interested in knowing if there is a general guideline for that kind of thing, especially if we are designing pedals that are going to have other pedals after it. Thank you for your help!


jwin615

Passive guitar outputs vary but typically quote din the 100-140mVrms range. Actives can get even further up there. Of course, you have to take the next devices input z into account...
There's no standard like consumer and balanced line levels. Instrument level is generally considered 0.1-1.7V
Around 0dBu is probably a good middle ground.

mauman

Quote from: satchmo1991 on September 06, 2024, 09:59:33 PMI have a bunch of different amps, but the one I was checking on is the Fender Mustang III. I couldn't find anything about input voltage in the manual.
The Mustang III has clipper diodes in the preamp section that will limit inputs above 1.1V RMS or so (3.2V p-p.)