Guitar amp hissing noise

sweetrelease · 28th February 2009

I have a fender frontman 65r and it makes alot of hiss noise. I tried remove noise before amplification, but it doesn't seem to work.

I've concluded that the noise is being generated from the amp itself.

After playing and recording the noise off the amp. I discovered that I want a filter that will cut frequency above 11175hz(F note)

Has anybody done this before?

From what I gather on some other website. Simpliest filter to design and build is a first order passive filter. I believe the circuit is to be place before the speaker output and after amplification, but I'm unsure of what values of capacitors I should be using.

the speaker is rated for a 8ohm load and the amp delivers 65watts of power.

sweetrelease · 28th February 2009

boink!

qsblues · 28th February 2009

Time to buy a new amp.

AmpHead · 1st March 2009

What kind of tone are you after? Adjusting levels between the guitar, any effects you may be running in the signal chain and the amp controls can minimize hiss.

What channel are you using? Do you have anything plugged into the FX loop? What are the controls set at?

Hiss is a product of resistive type components in the amp's circuitry and it's volume is dependent on the gain in the signal chain. There are likely some ways to set up the amp that will minimize the hiss and still get you the tone you want.

If you implement a lo pass filter with its 3 dB point at 11K you may lose enough upper harmonics to significantly alter the tone.

A post-output transformer filter should be wired in within the amp chassis - lots of dangerous voltages in there so experience and great care are required.

Anyway, per the above you may be able to get the hiss to a manageable level by altering controls in the signal path thereby boosting the signal to noise ratio.

sweetrelease · 2nd March 2009

I'm looking to get a cleaner sound.

I have a mexican stratocaster and replace the stock coils with a set of noiseless variety. I've gotten a better improvement in sound quality from just doing that and all my humming noises have disappeared.

Unfortunely I have a only a couple of crappy sounding foot pedals. Although I do like some of the sound they provide, but they have a bit of digit-titis in the higher bandwidth if you know what I mean.

I friend of mind recommended that I get something like Boss GE7 pedal, but I still feel that there is still quite a bit of noise coming from the amp. I'm still worried that the boss pedal will not remove the noise coming from it.

I don't think I would have too much of a problem lossing a few harmonics if it meant less noise.

CDA · 3rd March 2009

You don't need a filter and you don't need a new amp.

Your amp is old as hell (Which is good imo) and needs some service.

Have you noticed if the gain on the amp has shot up, or down...

First place I would check is the cathode bypass caps. These go bad, and cause all sorts of problems.

Your cathode resistor is usually around 820 ohm to maybe 3.3k

This resistor is paralleled by a capacitor. Usually a 25uf 25v for Fenders, and a .68uf for Marshals (That's why they sound different people)

Anyways, these go bad. It can cause hum, low gain, high gain (Hissing) etc etc

So, add all this up with other failing components and you get what you have here. Noise and undesirable performance.

I'm sure your decoupling caps are passing DC to the next stages which will throw the circuit out of whack.

drtechno · 19th March 2009

retube it

an imbalanced phase spitter tube can cause the tv static noise...

SAnthony · 20th March 2009

Frontman 65...... Are you using the internal reverb? If I remember correctly, these do have a hissy reverb circuit. And these are Solid State.. You don't have the capacitors that the tube Fenders do, So the reply with the Capacitors, probably doesn't apply to this amp. A lower setting on the Reverb might eliminate some of your hiss. As for Pedals, You might consider a Digitech RP80. Under $100 and lots of effects to choose from. You can also use the noise gate feature on RP80 to tame some of your unwanted noises. I think your noiseless Fender Pickups were a good choice to kill any hum problems... Can't remember all of the controls on Frontman 65, I think you have Seperate Gain and Volume. You might try to minimize your Gain Setting, boost your tone controls and push your volume knob a little harder to keep the hiss at a minimum as well...
Hope this helps a bit...
Take Care,
Shawn

28th February 2009	#1
sweetrelease Gear interested Join Date: Nov 2007 Location: Guelph, On, Canada Posts: 14 Thread Starter	Guitar amp hissing noise I have a fender frontman 65r and it makes alot of hiss noise. I tried remove noise before amplification, but it doesn't seem to work. I've concluded that the noise is being generated from the amp itself. After playing and recording the noise off the amp. I discovered that I want a filter that will cut frequency above 11175hz(F note) Has anybody done this before? From what I gather on some other website. Simpliest filter to design and build is a first order passive filter. I believe the circuit is to be place before the speaker output and after amplification, but I'm unsure of what values of capacitors I should be using. the speaker is rated for a 8ohm load and the amp delivers 65watts of power.

1st March 2009	#4
AmpHead Gear interested Join Date: Feb 2009 Location: Toronto Posts: 2	What kind of tone are you after? Adjusting levels between the guitar, any effects you may be running in the signal chain and the amp controls can minimize hiss. What channel are you using? Do you have anything plugged into the FX loop? What are the controls set at? Hiss is a product of resistive type components in the amp's circuitry and it's volume is dependent on the gain in the signal chain. There are likely some ways to set up the amp that will minimize the hiss and still get you the tone you want. If you implement a lo pass filter with its 3 dB point at 11K you may lose enough upper harmonics to significantly alter the tone. A post-output transformer filter should be wired in within the amp chassis - lots of dangerous voltages in there so experience and great care are required. Anyway, per the above you may be able to get the hiss to a manageable level by altering controls in the signal path thereby boosting the signal to noise ratio. __________________ Don Mackrill Mack Amps www.MackAmps.com Budget Boutique Guitar Amps Virtuoso Tone without the Prima Donna Price!

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28th February 2009	#3
qsblues Gear maniac Join Date: Jun 2008 Location: Camp Hill, PA Posts: 220	Time to buy a new amp.

2nd March 2009	#5
sweetrelease Gear interested Join Date: Nov 2007 Location: Guelph, On, Canada Posts: 14 Thread Starter	I'm looking to get a cleaner sound. I have a mexican stratocaster and replace the stock coils with a set of noiseless variety. I've gotten a better improvement in sound quality from just doing that and all my humming noises have disappeared. Unfortunely I have a only a couple of crappy sounding foot pedals. Although I do like some of the sound they provide, but they have a bit of digit-titis in the higher bandwidth if you know what I mean. I friend of mind recommended that I get something like Boss GE7 pedal, but I still feel that there is still quite a bit of noise coming from the amp. I'm still worried that the boss pedal will not remove the noise coming from it. I don't think I would have too much of a problem lossing a few harmonics if it meant less noise.

3rd March 2009	#6
CDA Gear maniac Join Date: Jan 2009 Posts: 236	You don't need a filter and you don't need a new amp. Your amp is old as hell (Which is good imo) and needs some service. Have you noticed if the gain on the amp has shot up, or down... First place I would check is the cathode bypass caps. These go bad, and cause all sorts of problems. Your cathode resistor is usually around 820 ohm to maybe 3.3k This resistor is paralleled by a capacitor. Usually a 25uf 25v for Fenders, and a .68uf for Marshals (That's why they sound different people) Anyways, these go bad. It can cause hum, low gain, high gain (Hissing) etc etc So, add all this up with other failing components and you get what you have here. Noise and undesirable performance. I'm sure your decoupling caps are passing DC to the next stages which will throw the circuit out of whack.

19th March 2009	#7
drtechno Lives for gear Join Date: Aug 2006 Location: Rapid City, SD Posts: 596	retube it an imbalanced phase spitter tube can cause the tv static noise...

20th March 2009	#8
SAnthony Gear nut Join Date: May 2007 Location: New Orleans Posts: 124	Frontman 65...... Are you using the internal reverb? If I remember correctly, these do have a hissy reverb circuit. And these are Solid State.. You don't have the capacitors that the tube Fenders do, So the reply with the Capacitors, probably doesn't apply to this amp. A lower setting on the Reverb might eliminate some of your hiss. As for Pedals, You might consider a Digitech RP80. Under $100 and lots of effects to choose from. You can also use the noise gate feature on RP80 to tame some of your unwanted noises. I think your noiseless Fender Pickups were a good choice to kill any hum problems... Can't remember all of the controls on Frontman 65, I think you have Seperate Gain and Volume. You might try to minimize your Gain Setting, boost your tone controls and push your volume knob a little harder to keep the hiss at a minimum as well... Hope this helps a bit... Take Care, Shawn