Buffer vs. Gain Stage! (Muff fuzz)

Frequent asked about building blocks: gain stages, buffers, clipping configurations, ...
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Emanuele
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Post by Emanuele »

Hi all! finally this is my first own topic!
My answer is:
I'm building a muff fuzz and I've read that it works a lot better when pushed by a buffer...and so it does now that I'm experimenting with the whole circuit..But for what I know, a buffer is something of a gain stage, right? so, why it won't do the same if pushed by a booster style pedal? For example I've tried integrating an LPB kind of stage before it but even on unity gain it sounds like ubuffered..there's something more in a buffer stage that a gain stage hasn't?

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bajaman
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Post by bajaman »

Think of a buffer as a bit like a brick wall in some respects - it effectively isolates what is going on from one side to the other.
However, unlike a brick wall, it still allows communication between the two sides - how does it do this? :hmmm:

The answer is that the buffer presents a very high (hopefully) impedance to whatever pedal or guitar that is connected to it's input - a high impedance does not appreciably load down whatever is connected to it - no tone sucking or loss of volume level etc.
The other side of the wall, or the output of the buffer is at a very low (hopefully) output impedance - this allows whatever the buffer is feeding to be driven by nearly the maximum output level of the preceeding device or guitar.
In some respects the buffer functions very similar to an isolation transformer, effectively decoupling the two connected devices.
A standard emitter follower, source follower or op amp buffer has very slightly less than unity gain - it is not designed for large voltage gain, more for it's isolation properties.

some folks like buffers - some don't, in the end it is a personal choice and very much a horses for courses decision.
Personally, I like to use buffers between successive gain stages for maximum performance and less interaction between each gain stage - i also like plenty of power supply decoupling too ( something that is often overlooked in multiple high gain circuits.

Hope this helps.
cheers
bajaman
be kind to all animals - especially human beings

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Emanuele
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Post by Emanuele »

:block:
Every time they told about buffer gain without specify on real buffer proprieties, that's why I wasn't understanding..THANKS A LOT BAJAMAN!!!
Now it's time to have some fun at the solder station! 8)

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Emanuele
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Post by Emanuele »

Resurrection time!
today I have completed my project, I've put a buffer like this in the jen fuzz III
Image
I've tought that, since my TS9's buffer works so well, I'll use this one in the Jen Fuzz wich is quite similar..
BUT, for some reason it doesnt sounds so good at all!
Any thoughts?

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gus
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Post by gus »

Jen fuzz buffer design. The bias network, look in the art of electronics
Take a meter set to voltage and connect it to the emitter, heat and cool the transistor and watch the meter.

What muff fuzz circuit? transistor IC BMP...?

The output R. If the two transistor muff see that 4.7K between stages of the Jen. Thats a clue. Also look for the 3 tran at Aron's site

Yo can redesign the first stage of a BMP to have higher input resistance

The thing a buffer might help you with is changing the input resistance. How a circuit loads a guitar etc can sometimes have an effect on the sound.

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Emanuele
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Post by Emanuele »

gus wrote:Jen fuzz buffer design. The bias network, look in the art of electronics
Take a meter set to voltage and connect it to the emitter, heat and cool the transistor and watch the meter.

What muff fuzz circuit? transistor IC BMP...?

The output R. If the two transistor muff see that 4.7K between stages of the Jen. Thats a clue. Also look for the 3 tran at Aron's site

Yo can redesign the first stage of a BMP to have higher input resistance

The thing a buffer might help you with is changing the input resistance. How a circuit loads a guitar etc can sometimes have an effect on the sound.
Thanks a lot gus, I'm in the two transistor muff case..I'll check this project on Aron's site..news coming soon
:wink:

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Emanuele
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Post by Emanuele »

Emanuele wrote:
gus wrote:Jen fuzz buffer design. The bias network, look in the art of electronics
Take a meter set to voltage and connect it to the emitter, heat and cool the transistor and watch the meter.

What muff fuzz circuit? transistor IC BMP...?

The output R. If the two transistor muff see that 4.7K between stages of the Jen. Thats a clue. Also look for the 3 tran at Aron's site

Yo can redesign the first stage of a BMP to have higher input resistance

The thing a buffer might help you with is changing the input resistance. How a circuit loads a guitar etc can sometimes have an effect on the sound.
Thanks a lot gus, I'm in the two transistor muff case..I'll check this project on Aron's site..news coming soon
:wink:
I can't find that schem. on Aron's page can you give me the link?

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Post by gnognofasciani »

Search button is your friend

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Emanuele
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Post by Emanuele »

gnognofasciani wrote:maybe this one :hmmm: :

https://www.diystompboxes.com/pedals/rocket.JPG
grazie mille!
actually I've seen that the Ts-9 output buffer has another 100k resistor after the condenser wich shunt the signal to ground..maybe it has something to do with my case since, what I hear when I used my muff fuzz in combo with my ts9 (turned OFF) is the fuzz pushed by the OUTPUT buffer.. I'll try some more tweaking!

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