[40] AMZ Jfet Buffer-Splitter

Date: August 26th, 2007 | Comments : [8] | Categories: DIY.

Guitar Pedal SplitterI was looking back at the jfet buffer presented earlier in this blog, and noted that it would be easy to add some extra transistors to the buffer to turn it into a multiple output signal splitter.

Also, the veroboard layout is easily extended to accomodate the extra components and I have included that in the article.

You can find it in the AMZ Lab Notebook.


8 Responses to “AMZ Jfet Buffer-Splitter”

[71] gaussmarkov Says: 4:27 pm, September 11th, 2007

hi! thanks for your many contributions to understanding stompboxes. i wasn’t sure where to write — and this seemed as good as any. in your Basic Buffers article, you refer to this JFET buffer as a “common source amplifier.” but in a wikipedia article, it is called a common drain or “source follower.” what is the proper term?

thanks, gm

[72] admin Says: 6:57 pm, September 11th, 2007

Yes, it’s supposed to be common drain. My slipup in terminology! Thanks for pointing it out; I’ll edit it shortly.

regards, Jack

[1257] hozone Says: 12:52 pm, July 15th, 2010

first thank you for this buffer!
i’ve readlized it and works perfect!!

now i’ve a question:
i would like to split the signal coming out from my pedal board (zoom g7.1ut), to put it both
1 – in a line level input and
2 – in a monitor line level input.

those are the specifications of the output of the pedal board:
* Rated output level: -10 dBm/ 4 dBm (switchable)
* Maximum output level: 19 dBm (into load impedance of 10 kilohms or more)
* Output impedance: 1 kilohm or less
now i use the 4dBm level and get into a mixer line level in, and i works good.

i would like to know if is this buffer will work good as a signal splitter for this type of line level.


[1261] admin Says: 6:31 am, July 18th, 2010

Output impedance of your pedalboard is 1k or less, so you do not need a buffer/splitter.

Just use a Y-cord and connect the pedalboard to your line and monitor inputs. If they are rated at 10k input impedance or higher, there should be not problem.

If you would like to build the splitter anyway, it should work well in your application.


[1262] hozone Says: 6:52 am, July 18th, 2010

thank you!

i prefer to build a buffer, because i also have long cables.
i’ve see read your documentation about buffers.
if i understaind, i can built a buffer / splitter even with BJT (like 2SC1815), because of the low impendance.
i’ve just to change R1 to 1M, R2 and R3 to 220k is that right?

[2079] LC Says: 2:50 pm, February 20th, 2011

First of all, thank you for creating and maintaining such a great stockpile of information. I am looking to build a device for myself that boosts at least two different chains of effects. Would you recommend putting a booster before the splitter or giving each output its own independent boost? Would it make a difference?

[3570] Neeno Says: 3:40 pm, November 7th, 2012

Dear Mr.Orman, thank you very much for all the projects and information. I tried to build this buffer-splitter doing my own pcb, and testing it on my bench it seems to work properly (and sounds really good) there is just a bit of hiss, but if I roll back the volume on my guitar it becomes really noisy. If i put my buffered tuner between my guitar and the splitter the noise goes away. Do you have any suggestion ?

Thank you very much.

[555052] Steve Says: 10:48 am, January 31st, 2015

Thank you for very helpful info and designs. I’ve successfully built the buffer/splitter. I have a couple of questions. I’m confused about the R value for R2 & R3. Should output (volume) go up or down when R2/3 value is increased?
Also, I’m driving a vocal harmonizer and would like a little higher output from guitar to the harmonizer without distorting the guitar signal to the guitar amp. Do I need to incorporate a “booster” or is there some mod I could make to the buffer/splitter so the output is higher to the harmonizer than to the guitar amp?


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