how to reduce humming in guitar amplifier

winner · 6th April 2009, 02:05 PM

i made a guitar amp usin tl072 as preamp and tda2050 as power it hums and buzzes annoyingly but they are reduced wenever i touch the circuit ground. plz help also, y r circuit grounds connected to chassis of the amp? do they help 2 reduce noise?

Test Electrix · 6th April 2009, 06:23 PM

And electric shocks. Might be radio interference, try angling the amp in different directions (sounds silly but you'll notice a difference if it does)

VictoriaGuy · 6th April 2009, 06:45 PM

Are your input jacks grounded (ie shorting-type, which connects signal ground to input- we are not necessarily talking about grounded chassis here, though that is common) ?
Is the buzzing present when the guitar is not plugged in and the input is shorted?
Answer: Yes- problem is in the amp.
Answer: No- problem is noise pickup from guitar/cable.

Just a point: You will likely get more responses if you use 'normal English' rather than 'texting' abbreviations in your posts. Some 'old fogeys' -like me- find it irritating to read......

Cheers
John

fugazied · 8th April 2009, 04:40 AM

Make sure you have properly shielded guitar cables.

Also check what else is plugged in to the same power adapter or in the house. Sometimes high voltage gear in a house can cause unusual hums to be heard through loud speakers at loud volumes

winner · 9th April 2009, 07:05 AM

theres no problem when the input is shorted but when the input is left floating( without connecting either to guitar and ground ) the hum is multifold .also is there any noise reduction
when the preamp is in inverting mode than in non inverting mode?

VictoriaGuy · 9th April 2009, 08:29 AM

Quote:

Originally posted by winner
theres no problem when the input is shorted

I'd say your amp sounds quite typical of most guitar amps- they are quite high gain, so sensitive to noise.
I you plug in a properly set-up guitar, using a good cord, you should be OK.

John

Minion · 9th April 2009, 11:17 PM

You might also consider shielding the cavity in your electric guitar which will help with noise and hum...

winner · 13th April 2009, 06:22 AM

will replacing tl072 with any other better quality preamp help? chips like opa 2134 are very hard to get here. is there a readily available good quality ic available for substitute of tl072/74 ?

Geek · 13th April 2009, 11:08 AM

G'day,

Quote:

Originally posted by winner
will replacing tl072 with any other better quality preamp help? chips like opa 2134 are very hard to get here. is there a readily available good quality ic available for substitute of tl072/74 ?

TL072 is a gorgeous op amp for HiFi and absolutely spectacular for guitar in my experience.

I think Test Electrix might have been on to something with "Might be radio interference". Any device pushed into saturation, transistor, opamp or tube, will hum like a son-of-a.

First thing I'd look at is grounding. I use a single point ground, even on my guitar amps.

Cheers!

Nigel Goodwin · 13th April 2009, 12:11 PM

Quote:

Originally posted by winner
will replacing tl072 with any other better quality preamp help? chips like opa 2134 are very hard to get here. is there a readily available good quality ic available for substitute of tl072/74 ?

I agree totally with Geek, the TL072 is a great opamp, I doubt you would hear any difference whatsoever - and certainly not in a guitar amp.

6th April 2009, 02:05 PM	#1
winner diyAudio Member Join Date: Jan 2009	how to reduce humming in guitar amplifier i made a guitar amp usin tl072 as preamp and tda2050 as power it hums and buzzes annoyingly but they are reduced wenever i touch the circuit ground. plz help also, y r circuit grounds connected to chassis of the amp? do they help 2 reduce noise?

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6th April 2009, 06:23 PM	#2
Test Electrix diyAudio Member Join Date: Mar 2009	And electric shocks. Might be radio interference, try angling the amp in different directions (sounds silly but you'll notice a difference if it does)

6th April 2009, 06:45 PM	#3
VictoriaGuy diyAudio Member Join Date: Dec 2008	Are your input jacks grounded (ie shorting-type, which connects signal ground to input- we are not necessarily talking about grounded chassis here, though that is common) ? Is the buzzing present when the guitar is not plugged in and the input is shorted? Answer: Yes- problem is in the amp. Answer: No- problem is noise pickup from guitar/cable. Just a point: You will likely get more responses if you use 'normal English' rather than 'texting' abbreviations in your posts. Some 'old fogeys' -like me- find it irritating to read...... Cheers John

8th April 2009, 04:40 AM	#4
fugazied diyAudio Member Join Date: Mar 2009	Make sure you have properly shielded guitar cables. Also check what else is plugged in to the same power adapter or in the house. Sometimes high voltage gear in a house can cause unusual hums to be heard through loud speakers at loud volumes

9th April 2009, 07:05 AM	#5
winner diyAudio Member Join Date: Jan 2009	theres no problem when the input is shorted but when the input is left floating( without connecting either to guitar and ground ) the hum is multifold .also is there any noise reduction when the preamp is in inverting mode than in non inverting mode?

9th April 2009, 11:17 PM	#7
Minion diyAudio Member Join Date: May 2006	You might also consider shielding the cavity in your electric guitar which will help with noise and hum...

13th April 2009, 06:22 AM	#8
winner diyAudio Member Join Date: Jan 2009	will replacing tl072 with any other better quality preamp help? chips like opa 2134 are very hard to get here. is there a readily available good quality ic available for substitute of tl072/74 ?

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