input buffers

Frequent asked about building blocks: gain stages, buffers, clipping configurations, ...
Post Reply
User avatar
AbuseArt
Breadboard Brother
Information
Posts: 127
Joined: 24 Mar 2009, 22:17
my favorite amplifier: laney lc15
Completed builds: Vox Clyde McCoy
Rebote Delay 2.5
Tube Screamer TS-808
Exotic AC Booster
Marshall Guv'nor
Big Muff Pi
Big Muff Triangle
EH Pulsar
Joe's Simple Overdrive
Location: Poland
Contact:

Post by AbuseArt »

Sorry for posting another thread but I think it should go to separate one.

1. Please show me input buffers you have done and you are happy with them. I want to place the buffer in wah-wah, tubescreamer, blue box, big muff triangle and some other pedals to protect my tone from input impedance of each pedal.

this is the way I want to use the buffers CLICK

I have few FETs and bc550Cs. Op amps too.


2. why this one has two 1M resistors?
https://img6.imageshack.us/img6/9443/buffers.jpg

User avatar
Silent Fly
Resistor Ronker
Information
Posts: 424
Joined: 27 Feb 2008, 22:40
Has thanked: 27 times
Been thanked: 48 times

Post by Silent Fly »

As a starting point I would recommend you have a look at any Boss schematics. A lot of them use transistor-based in/out buffers.
"Remember - all I am offering is the truth, nothing more". Morpheus

User avatar
modman
a d m i n
Information
Posts: 4890
Joined: 19 Jun 2007, 16:57
Has thanked: 4394 times
Been thanked: 2131 times

Post by modman »

viewtopic.php?f=13&t=858
viewtopic.php?f=22&t=2139
viewtopic.php?f=22&t=394

the last one is about the true bypass myth, you should have a look at that thread too.
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

User avatar
earthtonesaudio
Transistor Tuner
Information
Posts: 1244
Joined: 28 Jan 2008, 04:00
Completed builds: Metal Simplex, Fuzz Factory, two Fab Echos-modded, Noisy Cricket, Earth & Space Wah, TS-7-modded, passive xover/splitter box, opamp fuzz
Location: Bloomington, Indiana
Has thanked: 11 times
Been thanked: 75 times

Post by earthtonesaudio »

The buffer in red in the schematic doesn't need the .05 cap or the 1M resistor. Just connect from the top of the 100k wah pot directly to the JFET gate, no other connections to the gate, for better frequency response.
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

User avatar
AbuseArt
Breadboard Brother
Information
Posts: 127
Joined: 24 Mar 2009, 22:17
my favorite amplifier: laney lc15
Completed builds: Vox Clyde McCoy
Rebote Delay 2.5
Tube Screamer TS-808
Exotic AC Booster
Marshall Guv'nor
Big Muff Pi
Big Muff Triangle
EH Pulsar
Joe's Simple Overdrive
Location: Poland
Contact:

Post by AbuseArt »

@earthtonesaudio, does it fit to other effects?
do you think it solves my problem? Inputs are still unbypassed. Moreover there's resistance at output of this buffer. It has to be bypass improvement...

Today I compared my signal with two pedals and no pedals. I never realised two effects can kill so much trebles...

User avatar
AbuseArt
Breadboard Brother
Information
Posts: 127
Joined: 24 Mar 2009, 22:17
my favorite amplifier: laney lc15
Completed builds: Vox Clyde McCoy
Rebote Delay 2.5
Tube Screamer TS-808
Exotic AC Booster
Marshall Guv'nor
Big Muff Pi
Big Muff Triangle
EH Pulsar
Joe's Simple Overdrive
Location: Poland
Contact:

Post by AbuseArt »

Can I use 680nF NP instead of 1uF NP? Or electrolitic 1uF ?
What does this cap do?

User avatar
earthtonesaudio
Transistor Tuner
Information
Posts: 1244
Joined: 28 Jan 2008, 04:00
Completed builds: Metal Simplex, Fuzz Factory, two Fab Echos-modded, Noisy Cricket, Earth & Space Wah, TS-7-modded, passive xover/splitter box, opamp fuzz
Location: Bloomington, Indiana
Has thanked: 11 times
Been thanked: 75 times

Post by earthtonesaudio »

In your drawing here: download/file.php?id=3106
Your buffer is connected all the time to "input," so if the input is a guitar, you can replace the 1M pull down and input coupling cap with a wire going to the guitar's volume pot. This won't cause any noticeable "tone suck" until you have a lot (hundreds) of input buffers connected in parallel like this.

But I'm not quite clear on what you want to do/achieve. Do you want to add a buffer to each effect's input, or just use one buffer at the beginning of a chain of effects, or...?
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

User avatar
AbuseArt
Breadboard Brother
Information
Posts: 127
Joined: 24 Mar 2009, 22:17
my favorite amplifier: laney lc15
Completed builds: Vox Clyde McCoy
Rebote Delay 2.5
Tube Screamer TS-808
Exotic AC Booster
Marshall Guv'nor
Big Muff Pi
Big Muff Triangle
EH Pulsar
Joe's Simple Overdrive
Location: Poland
Contact:

Post by AbuseArt »

earthtonesaudio wrote:But I'm not quite clear on what you want to do/achieve. Do you want to add a buffer to each effect's input, or just use one buffer at the beginning of a chain of effects, or...?
Honestly, I'm not sure at all which way to choose. I'm waiting for some advice. I have very badly sucked tone, I lose a lot of trebles and volume even if I plug only Blue Box and Big Muff. 3PDTs are unavailable in my country but I still need diodes in most of pedals(but I'd love to have diode in each one). The worst problem is actually the Blue Box - it needs bypass with grounded input but this kind of wiring is absolutely not true bypass :( I have nice valve amp and want to hear its real sound.

what about millenium bypass?

User avatar
Fuzzer
Diode Debunker
Information
Posts: 982
Joined: 16 Sep 2007, 15:17
Been thanked: 21 times

Post by Fuzzer »

The grounded input bypass is true bypass, and yes, if you can only get DPDT switches, then you should go with millenium bypass which allows you to get true bypass and LED indicators. There is too much information around about it, starting from the creator's home, GEOFEX.

Other than that, you can still experience some serious muddying of your guitar's sound and it's because of the cables, sou you would benefit of having a buffer at the beginning of the effects.
The Freestompboxes Forum search function is soo great, use the search function..., the S E A R C H function.

User avatar
AbuseArt
Breadboard Brother
Information
Posts: 127
Joined: 24 Mar 2009, 22:17
my favorite amplifier: laney lc15
Completed builds: Vox Clyde McCoy
Rebote Delay 2.5
Tube Screamer TS-808
Exotic AC Booster
Marshall Guv'nor
Big Muff Pi
Big Muff Triangle
EH Pulsar
Joe's Simple Overdrive
Location: Poland
Contact:

Post by AbuseArt »

Fuzzer wrote:The grounded input bypass is true bypass
yep thats true. i'm very scatty and mixed sth up.

Is this version good? http://www.guitar-pedals-effects.com/No ... Image2.jpg
Can I use BF245A ?

User avatar
AbuseArt
Breadboard Brother
Information
Posts: 127
Joined: 24 Mar 2009, 22:17
my favorite amplifier: laney lc15
Completed builds: Vox Clyde McCoy
Rebote Delay 2.5
Tube Screamer TS-808
Exotic AC Booster
Marshall Guv'nor
Big Muff Pi
Big Muff Triangle
EH Pulsar
Joe's Simple Overdrive
Location: Poland
Contact:

Post by AbuseArt »

one more question: Is it worth to buy Darlingtons?

User avatar
RnFR
Old Solderhand
Information
Posts: 4879
Joined: 09 Jan 2008, 06:02
my favorite amplifier: Traynor YBA-III, Fender Super Six
Completed builds: custom fuzz.
Location: Inner Earth
Has thanked: 139 times
Been thanked: 133 times
Contact:

Post by RnFR »

AbuseArt wrote:
Fuzzer wrote:The grounded input bypass is true bypass
yep thats true. i'm very scatty and mixed sth up.

Is this version good? http://www.guitar-pedals-effects.com/No ... Image2.jpg
Can I use BF245A ?
i've used that version with good effect. and i don't think you need darlington transistors with buffers, as you aren't actually getting any extra gain out of the circuit anyway.
"You've converted me to Cubic thinking. Where do I sign up for the newsletter? I need to learn more about how I can break free from ONEism Death Math." - Soulsonic

Blog-APOCALYPSE AUDIO

User avatar
Fuzzer
Diode Debunker
Information
Posts: 982
Joined: 16 Sep 2007, 15:17
Been thanked: 21 times

Post by Fuzzer »

But the beta does increase the input impedance and the current gain.
The Freestompboxes Forum search function is soo great, use the search function..., the S E A R C H function.

Post Reply