Cheap and easy to make LowNoise Guitar PreAmp

TravelRec. · Jul 25, 2004, 01:14 PM

Hi folks!

Electricstart.de is now updated with a very small´n easy guitar-to-line preamp device for building it yourself. Features and description you´ll find under "Electronics" button. Have fun!
Comments and suggestions are welcome. RMAA testing later, have only a running prototype yet.

Greetings!

TravelRec.

**dj_stick** · Jul 25, 2004, 01:17 PM

hey very nice - my school wanted to build some of these

TravelRec. · Jul 25, 2004, 01:26 PM

Hey dj!

You´re the first reply (that was nearly clear to me

) - if you wanna build - please don´t burn your fingers - all is very small, but loud and clear (tested with el cheapo guitar and Tiger_M´s plug - very cool

).

Have fun!

TravelRec.

**dj_stick** · Jul 25, 2004, 01:27 PM

my school is also interested in the ADC project… btw i have a question in that thread you may be able to answer

markanini · Jul 25, 2004, 05:31 PM

I've got a few questions:
How much do all the parts cost? You can tell me in DM.
How good is it compared to a "real" preamp?

Tiger M · Jul 25, 2004, 07:40 PM

Oh yes!

Good job TravelRec.!

I haven't yet seen the schematics, but I was abscent for a few days and as soon as I saw the title of the thread I decided to answer.

All I can say is thanks and I'll be going to your site right away.
I'll post again later.

TravelRec. · Jul 25, 2004, 08:01 PM

Quote:

Originally posted by markanini
I've got a few questions:
How much do all the parts cost? You can tell me in DM.
How good is it compared to a "real" preamp?

What do you mean with "real" - this module is a real linear amp and makes nothing else than amplification - with over 85 db signal to noise ratio, if built in a metal shielded box with battery power. More details, if I´ve build this module for myself (only have free wired prototype yet...). Cost is around 10 EUR / 12 US$, dependent on quality of components.

BTW: Further update on electricstart: low noise linear phono (turntable) preamp (stereo). I hope one of the DSP gurus will implement a RIAA plugin next time

.

Stay tuned!

TravelRec.

Tiger M · Jul 25, 2004, 09:02 PM

Yep, it looks very promising. The components are some of the most common you can think of and very recently I found a small PCB factory that also makes custom PCBs for something like 5EUR a piece.

This will definetly be a success story for me.
I guess I'll be kicking the mixer I'm using for that purpose off my desk!

I'll be having loads of fun!

You do that too.

markanini · Jul 25, 2004, 11:30 PM

Quote:

Originally posted by TravelRec.
What do you mean with "real" - this module is a real linear amp and makes nothing else than amplification - with over 85 db signal to noise ratio, if built in a metal shielded box with battery power. More details, if I´ve build this module for myself (only have free wired prototype yet...). Cost is around 10 EUR / 12 US$, dependent on quality of components.
TravelRec.

I put the quotation around real which meant that I didnt think your preamp was a toy or anything I was just wondering how I compares to a factory made preamp.
I will buy a Emu 1212m sound card soon which has almost -120 dB measured moise level I think it would be pointless if a preamp would produce a higher noise level than if I just cranked the input gain, but I guess that depends on the components you use?

**dj_stick** · Jul 25, 2004, 11:41 PM

still it is an extremely low noise floor for a pre-amp
i am personally going to build one of these - maybe modify it for mic usage (or include a switch)

markanini · Jul 26, 2004, 12:58 AM

Would you be interested in building me one?
I have a friend that is in Germany right now, in a town called Freinhagen, is that anywhere close to where you live?
I just realised that DM doesnt exist anymore, it all Euros now

TravelRec. · Jul 26, 2004, 07:30 AM

Quote:

Originally posted by Tiger M

I guess I'll be kicking the mixer I'm using for that purpose off my desk!

Yeah, be careful that nobody is standing behind the window, and better open it before you do that

!

TravelRec. · Jul 26, 2004, 07:44 AM

Quote:

Originally posted by markanini
I put the quotation around real which meant that I didnt think your preamp was a toy or anything I was just wondering how I compares to a factory made preamp.
I will buy a Emu 1212m sound card soon which has almost -120 dB measured moise level I think it would be pointless if a preamp would produce a higher noise level than if I just cranked the input gain, but I guess that depends on the components you use?

Yes, but never believe some comments of the manufacturers if you don´t have tested the noise input of your card. -120db is utopic - a simple cable that you connect to it has more noise! And don´t forget - like dj said - this thingy is a preamp, so it will amplify everything you apply on the input by ~3 to 5 times (dependent of gain set), so all noise on input will be amplified too. And if you want to connect an electrical guitar, you must amplify the relatively weak signal of it, due to impedance mismatch of guitar out and line in (you cannot connect a guitar directly to line without damaging the sound). Finally the quality of guitar´s pickups is essentially for S/N ratio, since they pick up nearly everything too (amp w/o guitar here: -85db, w/ guitar best level: -68db).

Greetings!

TravelRec.

P.S.: Yes, I can build it for you, but I think you could it do for yourself - it´s quite easy - shipping is much more expensive than the whole amp! But why not...

TravelRec. · Jul 26, 2004, 02:47 PM

Hi again!

Have posted a sound example here . This is for you to check the quality of the amp. Note: I´m not a guitar player, I´ve done this only for the test

!
At the end of the sound I stopped playing for a break - this is the noise input of the amp [COLOR=orange]after[/COLOR] fuzz plugin.

Added plugins: Tiger_M´s Classic fuzz (drive gain 37, tone 15k, polish 50% and level 0.4)
Max M´s Reverb R (some reverb)

Have fun!

TravelRec.

Tiger M · Jul 26, 2004, 04:36 PM

Very good. It sounds very punchy somewhat similar to a guitar combo, which must be due to good impendance match and there is practically no noise (if you remove the fuzz plugin there will not be ANY, I'm shure).

btw, nice groove!

Why don't you specificly outline (in a new thread) that it can also be built to serve as a microphone pre-amp, because when non-guitarists see "guitar" in the title they don't even bother to look. And I'm shure that many people would find this thing very useful.

In 2-3 days I'll be ready with two of these - one for my strat and one for my mic.

Thanks TravelRec.

Tiger M · Jul 26, 2004, 09:39 PM

One question: does the "tau" in the values of some caps stand for micro farad? If not, what does it stand for? I'm not familiar with that notification.

**dj_stick** · Jul 26, 2004, 10:52 PM

do you mean the symbol that looks like a U with some accented strokes? if so that normally means micro

markanini · Jul 27, 2004, 12:20 AM

Wow, I'm impressed. I seems that the preamp amplifies the sound without without adding any noise(I must be slow).
Now I really want you to build me one of these. I would like a mic preamp two, would it be built in the same box as the guitar preamp and can you have 48v phantom power?
Good guitar and mic preamps can cost hundreds of euros, if you cuild build me one of these for a fair price for the parts and for your work i would be eternally greatfull! I'm sure I could'nt built one of these myself if my life depended on it.
By the way, could you also test it with a high gain setting similar to that modern high gain sound and uppload it as an mp3?
And which encoder did you use? You shouldnt get any artefacts at that bitrate with for example lame 3.96.

Tiger M · Jul 27, 2004, 06:50 AM

Quote:

do you mean the symbol that looks like a U with some accented strokes? if so that normally means micro

You're talking of the greek letter "miu" which really means micro, I ment the greek letter "tau" - like a T, but small. It should either mean micro(?) or pico. I hope TravelRec. responds soon.

TravelRec. · Jul 27, 2004, 07:23 AM

Yo, hi!

I´m here, just out of bed

- afaik no tau in my diagrams, only mju (µ, means microFarad) and nF (nanoFarad), nothing else. Hope it helps. Thanks for comments - fine that the amp meets your desire

!

Note: Positioning layout was revisited, R2 has changed to 10k - better range of gain. Please redownload it!
and if some things are hidden, zoom the layout to 200% and print it out.

Greetings!

TravelRec.

Tiger M · Jul 27, 2004, 08:00 AM

Ok, at my side C1, C3, C4, C5 are with a "tau" - like 3T3 and so on. I guess they should be with a "mju", right?

They should be microFarad?

TravelRec. · Jul 27, 2004, 08:06 AM

Yes, correct, 3.3 microFarad. Strange thing with that "tau"...

Greetings and have a nice puzzle

!

TravelRec.

P.S. Ahhh, before I forget - please post your experiences with it here, okay?

Tiger M · Jul 27, 2004, 09:32 AM

Quote:

please post your experiences with it here, okay?

Of course. Tomorrow I'll be going for the components and I will also order the PCBs.

One thing: Is it really necessary for some of the components to be SMD? I'll be having a hard time soldeing these.

TravelRec. · Jul 27, 2004, 02:41 PM

Quote:

One thing: Is it really necessary for some of the components to be SMD? I'll be having a hard time soldeing these.

No, not if you want to make your own design... for my PCB-design it´s a must be

, but serious: the same circuitry will work with standard size components. It´s a lot bigger (thicker) with them - be careful: you need big ground planes under the op-amp and around the input stage, and you will need a bigger box to build the thing in. The first complete device is ready here - take a look:
http://www.electricstart.de/pic/preamp.jpg

Greetings!

TravelRec.

**dj_stick** · Jul 27, 2004, 02:43 PM

looks like a very portable unit, top job there travelrec

TravelRec. · Jul 27, 2004, 02:55 PM

Yes, it is...

- one of the main advantage to put it inside your guitar bag - you could connect the thing wherever you wanna play and a line input is available. Finally you can do "out of house" clean recordings with an MD portable or similar and then - back at home - push it up on your computer

- I think I make some of the amps for my outdoor equipment - who knows; sometimes I will need them...

Greetings!

TravelRec.

Tiger M · Jul 27, 2004, 04:08 PM

That's small alright, but I've never soldered any smd components, so I'll go for standart ones.

Question: suppose I wanted to put a LED somewhere, where should it be so it would not alter the sound in any way?

TravelRec. · Jul 28, 2004, 08:20 AM

Hi!

So if you´ve never tried - try it! The only things you need are a fine solder tip, 0.5mm solder wire, pair of tweezers and a steady hand

, I´m sure it works also for you. There are parts, they are even smaller - I´ve selected the biggest SMDs available (1206 resistors are 1 wide and 2 mm long, big enough to handle!).
The power LED (I guess) you can put right after the power switch (that is connected with +) over a resistor of 2k and a Z-diode of 5.6V - so if the LED light disappears, then the battery must changed or charged (Note: cathode of Z-diode in switch direction!). There is no sound affection by the LED, only some power consumption.

battery + -------switch ----------:::::------------[<------------>|---------- GND

.......................................2kOms...... ..Z-diode.......LEDred

Greetings!

TravelRec.

bling · Jul 29, 2004, 03:53 AM

great job travelrec. think you could make it so the gain control is on the outside of the case? kind of a pain if you need to adjust it for different instruments

Tiger M · Jul 29, 2004, 07:22 AM

TravelRec., there's one more thing I want to ask you:

Is it necessary for some of the caps to be tantal? At one shop they told me that they were designed for very high temperatures and that they were not very stable.

Thnx

Jul 25, 2004, 01:14 PM	#1
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Cheap and easy to make LowNoise Guitar PreAmp Hi folks! Electricstart.de is now updated with a very small´n easy guitar-to-line preamp device for building it yourself. Features and description you´ll find under "Electronics" button. Have fun! Comments and suggestions are welcome. RMAA testing later, have only a running prototype yet. Greetings! TravelRec. __________________ Always take a look behind.

Jul 25, 2004, 01:26 PM	Thread Starter #3
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Hey dj! You´re the first reply (that was nearly clear to me ) - if you wanna build - please don´t burn your fingers - all is very small, but loud and clear (tested with el cheapo guitar and Tiger_M´s plug - very cool ). Have fun! TravelRec. __________________ Always take a look behind.

Jul 25, 2004, 07:40 PM	#6
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	Oh yes! Good job TravelRec.! I haven't yet seen the schematics, but I was abscent for a few days and as soon as I saw the title of the thread I decided to answer. All I can say is thanks and I'll be going to your site right away. I'll post again later. __________________ Miss you, Steve...

Jul 25, 2004, 09:02 PM	#8
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	Yep, it looks very promising. The components are some of the most common you can think of and very recently I found a small PCB factory that also makes custom PCBs for something like 5EUR a piece. This will definetly be a success story for me. I guess I'll be kicking the mixer I'm using for that purpose off my desk! I'll be having loads of fun! You do that too. __________________ Miss you, Steve... Last edited by Tiger M; Jul 25, 2004 at 09:29 PM.

Jul 26, 2004, 02:47 PM	Thread Starter #14
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Hi again! Have posted a sound example here . This is for you to check the quality of the amp. Note: I´m not a guitar player, I´ve done this only for the test ! At the end of the sound I stopped playing for a break - this is the noise input of the amp [COLOR=orange]after[/COLOR] fuzz plugin. Added plugins: Tiger_M´s Classic fuzz (drive gain 37, tone 15k, polish 50% and level 0.4) Max M´s Reverb R (some reverb) Have fun! TravelRec. __________________ Always take a look behind.

Jul 25, 2004, 05:31 PM	#5
markanini DriverHeaven Junior Member Join Date: Jun 2003 Posts: 22 Rep Power: 0	I've got a few questions: How much do all the parts cost? You can tell me in DM. How good is it compared to a "real" preamp?

Jul 26, 2004, 12:58 AM	#11
markanini DriverHeaven Junior Member Join Date: Jun 2003 Posts: 22 Rep Power: 0	Would you be interested in building me one? I have a friend that is in Germany right now, in a town called Freinhagen, is that anywhere close to where you live? I just realised that DM doesnt exist anymore, it all Euros now

Jul 26, 2004, 04:36 PM	#15
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	Very good. It sounds very punchy somewhat similar to a guitar combo, which must be due to good impendance match and there is practically no noise (if you remove the fuzz plugin there will not be ANY, I'm shure). btw, nice groove! Why don't you specificly outline (in a new thread) that it can also be built to serve as a microphone pre-amp, because when non-guitarists see "guitar" in the title they don't even bother to look. And I'm shure that many people would find this thing very useful. In 2-3 days I'll be ready with two of these - one for my strat and one for my mic. Thanks TravelRec. __________________ Miss you, Steve...

Jul 26, 2004, 09:39 PM	#16
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	One question: does the "tau" in the values of some caps stand for micro farad? If not, what does it stand for? I'm not familiar with that notification. __________________ Miss you, Steve...

Jul 27, 2004, 12:20 AM	#18
markanini DriverHeaven Junior Member Join Date: Jun 2003 Posts: 22 Rep Power: 0	Wow, I'm impressed. I seems that the preamp amplifies the sound without without adding any noise(I must be slow). Now I really want you to build me one of these. I would like a mic preamp two, would it be built in the same box as the guitar preamp and can you have 48v phantom power? Good guitar and mic preamps can cost hundreds of euros, if you cuild build me one of these for a fair price for the parts and for your work i would be eternally greatfull! I'm sure I could'nt built one of these myself if my life depended on it. By the way, could you also test it with a high gain setting similar to that modern high gain sound and uppload it as an mp3? And which encoder did you use? You shouldnt get any artefacts at that bitrate with for example lame 3.96. Last edited by markanini; Jul 27, 2004 at 12:30 AM.

Jul 27, 2004, 07:23 AM	Thread Starter #20
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Yo, hi! I´m here, just out of bed - afaik no tau in my diagrams, only mju (µ, means microFarad) and nF (nanoFarad), nothing else. Hope it helps. Thanks for comments - fine that the amp meets your desire ! Note: Positioning layout was revisited, R2 has changed to 10k - better range of gain. Please redownload it! and if some things are hidden, zoom the layout to 200% and print it out. Greetings! TravelRec. __________________ Always take a look behind.

Jul 27, 2004, 08:00 AM	#21
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	Ok, at my side C1, C3, C4, C5 are with a "tau" - like 3T3 and so on. I guess they should be with a "mju", right? They should be microFarad? __________________ Miss you, Steve...

Jul 27, 2004, 08:06 AM	Thread Starter #22
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Yes, correct, 3.3 microFarad. Strange thing with that "tau"... Greetings and have a nice puzzle ! TravelRec. P.S. Ahhh, before I forget - please post your experiences with it here, okay? __________________ Always take a look behind. Last edited by TravelRec.; Jul 27, 2004 at 08:16 AM.

Jul 27, 2004, 02:55 PM	Thread Starter #26
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Yes, it is... - one of the main advantage to put it inside your guitar bag - you could connect the thing wherever you wanna play and a line input is available. Finally you can do "out of house" clean recordings with an MD portable or similar and then - back at home - push it up on your computer - I think I make some of the amps for my outdoor equipment - who knows; sometimes I will need them... Greetings! TravelRec. __________________ Always take a look behind.

Jul 27, 2004, 04:08 PM	#27
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	That's small alright, but I've never soldered any smd components, so I'll go for standart ones. Question: suppose I wanted to put a LED somewhere, where should it be so it would not alter the sound in any way? __________________ Miss you, Steve...

Jul 28, 2004, 08:20 AM	Thread Starter #28
TravelRec. Alternative Audioproductions Join Date: Sep 2003 Location: Germany / Sachsen-Anhalt Posts: 1,710 Rep Power: 56	Hi! So if you´ve never tried - try it! The only things you need are a fine solder tip, 0.5mm solder wire, pair of tweezers and a steady hand , I´m sure it works also for you. There are parts, they are even smaller - I´ve selected the biggest SMDs available (1206 resistors are 1 wide and 2 mm long, big enough to handle!). The power LED (I guess) you can put right after the power switch (that is connected with +) over a resistor of 2k and a Z-diode of 5.6V - so if the LED light disappears, then the battery must changed or charged (Note: cathode of Z-diode in switch direction!). There is no sound affection by the LED, only some power consumption. battery + -------switch ----------:::::------------[<------------>\|---------- GND .......................................2kOms...... ..Z-diode.......LEDred Greetings! TravelRec. __________________ Always take a look behind.

Jul 29, 2004, 03:53 AM	#29
bling DriverHeaven Junior Member Join Date: Dec 2003 Posts: 24 Rep Power: 0	great job travelrec. think you could make it so the gain control is on the outside of the case? kind of a pain if you need to adjust it for different instruments

Jul 29, 2004, 07:22 AM	#30
Tiger M kX user Join Date: Apr 2004 Posts: 851 Rep Power: 0	TravelRec., there's one more thing I want to ask you: Is it necessary for some of the caps to be tantal? At one shop they told me that they were designed for very high temperatures and that they were not very stable. Thnx __________________ Miss you, Steve...