Can you overload/clip a buffer

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psychodave

psychodave

Well-known member
I’m in the process of building my own buffer. I was going to have an input buffer and output buffer in one pedal and create a loop for the effects. I was wondering if I could possibly drive the output buffer too much and cause it to clip? I typically dont need to drive an amp, but I’m more curious if I need to worry about it?

Also, would it be better to have the input jack grounded or the output jack (or all 4 of the jacks)?
 
Yes, you can clip it.

My TC Polytune with the Bonafide buffer has tons of headroom. But with hot pickups, it's not hard to overdrive a TU-3's or a TS808's buffer.
 
Yes, you can. Running a higher voltage like 18v or 27v or something can help with that.

This is why some distortion pedals use diodes before the first opamp, like the VH4 pedal for example. This is also what causes Marshall 8100s to go bad, people kill the first opamp with too much signal.
 
Depends on the type of design. Current driven or voltage driven impedance buffers. There’s a lot of various different ways to design an impedance buffer. The most common are voltage controlled, which means there’s a peak voltage tolerance on the input of whatever device you’re using which is your true limit to the buffer.

TLDR; you have to read the data sheets of the components and take note of the absolute maximums. If you’re doing fancy things like cascodes or source/emitter degeneration or bootstrapping then you need to be mindful of node to node voltages since the datasheet will no longer be valid on its own.
 
griff10672 said:
Do you have a schematic you're working off of Dave ?
Click to expand...
I am building a single pedal with this buffer at the input and output. In between will be a loop (input and output) for my pedals. I figured it was easier to build all in one box vs two separate buffer pedals.

This buffer is based off of the the Cornish LD-1

1700707056920.png
 
psychodave said:
I am building a single pedal with this buffer at the input and output. In between will be a loop (input and output) for my pedals. I figured it was easier to build all in one box vs two separate buffer pedals.

This buffer is based of
Click to expand...
so you're running two of these circuits in one enclosure with a loop wired in between them ?

how are you wiring it up ? point to point ? Tagboard ? you have a PCB made up ?

I'm pretty new to needing / using buffers ..... A few months back I bought a amp switcher ..... and with all the cable you need to run I ended up needing a buffer on my input ... and my output . Luckily I had a Boss ES-8 that I wasn't really using till now ... the buffers in the thing totally solved my problem ... they create a few others ... but with the ability to shut them on / off with patch changes has gotten me around most of them .
 
griff10672 said:
so you're running two of these circuits in one enclosure with a loop wired in between them ?

how are you wiring it up ? point to point ? Tagboard ? you have a PCB made up ?

I'm pretty new to needing / using buffers ..... A few months back I bought a amp switcher ..... and with all the cable you need to run I ended up needing a buffer on my input ... and my output . Luckily I had a Boss ES-8 that I wasn't really using till now ... the buffers in the thing totally solved my problem ... they create a few others ... but with the ability to shut them on / off with patch changes has gotten me around most of them .
Click to expand...
I have a few of this kit based on the Cornish LD-1 buffer. https://shop.pedalparts.co.uk/product/creambuff

I was going to wire it into a MXR style box. I was going to put two into one enclosure. This way it would be easier to wire up power, etc. instead of making tow separate buffers. So my signal would look like the following: Guitar > 20 foot cable > buffer > any effects I want to use > buffer > 10 foot cable into the amp. I was worried if I use something like the VFE standout into a clean amp and drive the amp hard, would the buffer clip (likely yes).

I'm likely over thinking it, but some of my questions are about grounding. Would it be better to use all metal jacks or use three plastic (isolated) and one metal jack that would ground the box. Should I ground both buffers together at one point? Honestly, I could just make two separate buffers, but was just looking for an easy way to incorporate two into one for power simplicity. As a point of interest, I have a cheapo Moskey buffer and found interesting that they didnt ground the output jacks together. When I pulled out the input cable it would buzz loudly. I ended up grounding both jacks and the noise was eliminated.
 
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interesting ... where my buffers are placed in my chain my input buffer comes right before the front end pedals .... like you described ... but my output buffer is after my last pedal in my fx loop run .... I think you might be good just having the one at your input ... but obviously experiment to see what works best .. .
as far as grounding .... in anything I've ever built or taken apart .... the jacks are always grounded ... all of them .... the only case where they weren't was the footswitch I just made for my Shiva ... it required the jack to not ground to the chassis ... the relay circuit runs a " open ground "
 
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