Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Amplifier Discussion => Topic started by: bsilverop on February 18, 2023, 05:57:42 PM

Title: Orange 35RT humming/buzzing
Post by: bsilverop on February 18, 2023, 05:57:42 PM
I just started playing again after about a 20 year break. I bought a new Orange 35RT amp and plugged my old epiphone SG into it, and the amp makes a very loud buzzing/humming sound when I turn up the gain past 20%. I tried new cables as well without any change. It stops if I put my finger on the string or another metal part of the guitar. Thinking it was the old guitar, I went out and bought a new one, and the exact same thing happens.

Unfortunately I don't have any other amp to test on at home, but seems like the issue is with the amp. I'm thinking of returning it and exchanging for another one, but wondering if this has happened to someone else before. Thanks!
Title: Re: Orange 35RT humming/buzzing
Post by: Loudthud on February 19, 2023, 12:26:26 AM
Is the amp being plugged into a working, properly grounded outlet ? Try a different outlet. If that doesn't work, take it back to where you purchased it and see if it works there.
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 19, 2023, 07:44:14 AM
Quote from: Loudthud on February 19, 2023, 12:26:26 AMIs the amp being plugged into a working, properly grounded outlet ? Try a different outlet. If that doesn't work, take it back to where you purchased it and see if it works there.
Yes I've also tried other outlets throughout the house and have the same issue. I'm going to take it to the shop where I bought my new guitar and see that everything works fine on one of their amps to rule out the guitar, and will probably take my amp with me. I requested a return on Amazon where I bought it but want to make sure it's not my guitars or outlets first. Thanks!
Title: Re: Orange 35RT humming/buzzing
Post by: willpirkle on February 19, 2023, 08:33:58 AM
Is the pitch of the hum between a Bb and a B?
Title: Re: Orange 35RT humming/buzzing
Post by: g1 on February 19, 2023, 02:05:40 PM
How can you play without touching the strings?
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 19, 2023, 03:38:17 PM
Not sure it is any note in particular. Ignoring the last comment, but here's a video of the issue as well.

https://youtube.com/shorts/iqXa2sbDFOY?feature=share
Title: Re: Orange 35RT humming/buzzing
Post by: willpirkle on February 19, 2023, 04:42:21 PM
Ok - if you hum along with the hum, that's right around Bb - B, which is 60Hz or 120Hz, so bad filter cap(s) would be my first guess. If it's been a long time since you played it, this makes a bit of sense, dried out electrolytics. If you know what you're doing, open it up and measure AC volts across the power supply filter caps (across the cap leads, NOT from each lead to ground). You should get 0.00Vac since caps pass ac voltage. If you get a measurable AC voltage across a filter cap, there's the culprit. If caps look good and clean, then I'd try to hunt down a ground problem, which by nature can be frustrating, so lots of patience... On occasion I've run across bad filter caps on op-amp supply pins, and FET drain pins (when bypassed), but that's been more rare for me. Hope that helps. If you have any trepidation at all about opening the amp or measuring those caps, take it to a tech, not worth getting hurt over a silly cap. - Will
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 19, 2023, 04:45:44 PM
Thanks for the reply. This is a brand new amp, so will likely return it before cracking it open. Don't want to be blamed for damaging it or voiding the warranty if I open it up. I wish I found this forum before giving away my 25 year old fender amp that wasn't working after plugging it in for the first time in almost as long. Thanks again!
Title: Re: Orange 35RT humming/buzzing
Post by: willpirkle on February 19, 2023, 05:10:39 PM
Ah - OK, I think I had my threads crossed (someone who had just pulled an old amp out of a closet, on another one, sorry). Usually the bad cap issue takes time, but failures on new components can and do occur. For sure, this blatant problem would rarely get past QA. Or maybe it was a late day at the factory and someone wanted to go home. Could have been damaged/jiggled during shipping... This is a great site to bookmark - lots of knowledge here from some amazing techs with decades of experience (g1 and phatt, especially, have some serious chops!)
Title: Re: Orange 35RT humming/buzzing
Post by: joecool85 on February 20, 2023, 03:40:09 PM
Sounds to me like poor grounding and/or picking up electric interference on your circuit.  If you touch the strings on your guitar does it change the hum?  What about pickup selection?  Tone/volume knobs on the guitar make it change?  Unplug the guitar entirely and try the amp again - same noise?
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 20, 2023, 04:01:49 PM
When I touch the strings or tuning knob, the hum dampens a bit (maybe 75%) but is still there. If I adjust the pickup volumes, same thing. I ordered a new amp (same one) and hoping the issue goes away. Otherwise I'm clueless l, but ordered a circuit tester to check for any grounding issues in my outlets to rule that out.


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Title: Re: Orange 35RT humming/buzzing
Post by: g1 on February 20, 2023, 04:08:15 PM
Quote from: bsilverop on February 19, 2023, 03:38:17 PMIgnoring the last comment


If you are referring to me, perhaps you misunderstand my comment, or I misunderstood the original post.
You said the hum goes away when you touch the strings.  I was trying to get you to think about the issue from a different angle, or re-direct the conversation to see if others here thought the hum could possibly be normal.
Does the amp perform normally while you play?  If so, it seems there is an issue with your guitar shielding or cable.  Or maybe a bad interference issue.
Without touching any metal parts on the guitar, turn the guitar's volume controls all the way down.  Does that make the hum go away?
Title: Re: Orange 35RT humming/buzzing
Post by: phatt on February 20, 2023, 06:06:50 PM
The buzz on the video is most likely switchmode power supply high frequency switching.
IF these Smode supplies are not well grounded then the hi Freq switching will bleed through into you audio circuitry.
Some are horrendously noisy if badly designed.

Just one thing you may not have tested is the power cord back to wall.
If the earth wire is faulty (Open circuit) then even the best designed Smode system will bleed through.
  Swap the cord for another and report back.

One other possible issue, your house wiring may not be up to standard.
Try another house, see if the issue resolves.
Phil.
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 20, 2023, 07:22:58 PM
I had considered trying another house before returning the amp, but have a new one on the way so I can report back then. I don't think the hum was present with the pickup volume turned down, but can't say for certain. I should have tried another power cable prior, but the manufacturer just suggested a swap before troubleshooting too much.

Hopefully the issue is just gone with the new amp, otherwise I would suspect the house as the culprit, since the issue happens on two guitars (one really old one, and one brand new Gibson LP Standard), and 3 different cables. 

I do have a few non standard things running in the home that I can try turning off in case of interference, so thanks for that suggestion as well.. I hadn't considered interference prior.

Thanks again!
Title: Re: Orange 35RT humming/buzzing
Post by: phatt on February 21, 2023, 01:54:40 AM
Yes if you turn down the volume on the guitar you are grounding the audio input and hence no noise.

These Smode supplies radiate hash out into the air and the high Z input of the Guitar audio circuit picks this up.
And yes ANYTHING that uses Smode supplies in the room/house such as computers and like can wreak havoc on your sound because they travel back through the wiring of the house as well as into the air.

With the old Copper and Iron transformers any noise was low freq hum. but unlike Smode they did not radiate very far into the surrounding space.

With a Transformer you just had to keep the power Tx away from the sensitive input when you designed the layout of the chassis and usually there was no big problem.
Phil.
Title: Re: Orange 35RT humming/buzzing
Post by: joecool85 on February 22, 2023, 08:46:18 PM
I could be wrong, but I don't think these use switchmode.  I've never been inside of one though.
Title: Re: Orange 35RT humming/buzzing
Post by: phatt on February 24, 2023, 04:50:33 PM
Hey Joe,
Yes, possible but as these things are fairly recent, i.e. not 30 years old then likely they are Sw-mode.
I did find a couple of demos on the tube and I noted they do buzz on the high gain setting, as do a lot of budget amps.

I spent a long time trying to find ways around noise issues with hi gain circuitry. Sadly the market is flooded with Amps/Pedals that are badly designed and the novice is ever burdened with the dreaded noise issue.

Then they are told they need a noise gate,,so everything becomes a patchup job to overcome a design problem.
I can do drop D on my strat and crank the gain and play some suspect heavy metal riffs and although there is more hiss it's way way less than what these amps sound like.

I spread my Drive/Dist over 3 dirt circuits,, if you try to do that much gain with just one circuit then say hello to the dreaded noise issue.
Phil.
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 27, 2023, 09:47:12 AM
Just to follow up on this, I got a replacement amp and it has the same issue. Clearly not the amp, as this is the second brand new one I've tried, and also bought a Bugera v5 infinium in the meantime, which also has the same issue. The Bugera is only 5w and has an attenuator which dampens the hum/buzz. I put an attenuator on the Orange RT35 as well, which makes it tolerable. I tried turning off some things in the house (power strips with computers plugged in, etc..), but nothing seems to help this. May just use a noise gate and carry on. Thanks again!


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Title: Re: Orange 35RT humming/buzzing
Post by: phatt on February 27, 2023, 04:46:59 PM
Well obviously this is the price you pay for budget bedroom amps. :-X
These things are designed to a price not quality R&D. They just bump up the gain and tweak the EQ for the kids to get that crunch tone as that is the fashion now.

Q, Are you using high quality guitar cords?
When using these hi gain amps you definitely need the best cables.
Canare is one of the best but not cheap.
Another thing that may not be obvious, at home the buzz is nearly always annoying but in a band situation the music level is a lot louder and the Buzz is not so obvious, at least while you are playing.

As I mentioned last post, When you design a circuit and just use one stage to crank all the gain the result is noise. Which is most likely the issue in this Amplifier.

I Actually use a very basic keyboard amp with no fancy crunch circuits.
All my sound is derived by intelligent pedal circuits.
Even at bedroom level with all 3 distortion circuits engaged the noise is hardly noticed when not playing. May I say this took me years to workout exactly what was going on but glad I perceived.
Phil.
Title: Re: Orange 35RT humming/buzzing
Post by: willpirkle on February 27, 2023, 06:13:15 PM
Not sure if you answered before, but have you tried someone else's house AC outlets, just as a grounding sanity check? The buzzing in the video you posted is obtrusive and unless you use single-coils, or live under a radio tower (this happened to the Talking Head's drummer), it's hard to believe all 3 amps would have this issue. I get the "cheap amp" comments but still.... My Orange TinyTerror doesn't buzz like that.
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 28, 2023, 11:41:42 AM
I'm using D'Addario cables after suspecting the issue may have been older/lower quality cables. I can try the brand mentioned and see if that helps any.

I haven't yet tried another home, but am going to soon. I was trying to rule out any devices in my home that may be causing the issue. I have a home energy monitor that has amp meters wrapped around the mains that I wonder if it's contributing to the issue or not.

Otherwise, it could be lower quality amps with gain cranked up, but it seems pretty harsh and not something I've seen in demos or reviews on either amp. I get it if people want zero buzz/hum, but this seems excessive.


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Title: Re: Orange 35RT humming/buzzing
Post by: Tassieviking on February 28, 2023, 11:57:28 AM
It seems there are a few around with the same problem.
https://www.tdpri.com/threads/orange-crush-35rt-speaker-buzz.834557/
https://www.reddit.com/r/orangeamps/comments/zyl3y0/35rt_constant_buzz/
Title: Re: Orange 35RT humming/buzzing
Post by: bsilverop on February 28, 2023, 03:15:14 PM
Quote from: Tassieviking on February 28, 2023, 11:57:28 AMIt seems there are a few around with the same problem.
https://www.tdpri.com/threads/orange-crush-35rt-speaker-buzz.834557/
https://www.reddit.com/r/orangeamps/comments/zyl3y0/35rt_constant_buzz/
I had seen those too, however this happened with two brand new ones, and another new Bugera v5 Infinium I bought while waiting on the new 35RT to arrive. Looking forward to trying another house, but at that point I'm not sure what it tells me if it works ok elsewhere.


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Title: Re: Orange 35RT humming/buzzing
Post by: phatt on March 02, 2023, 03:24:53 PM
If another house resolves the problem then time to call an electrician and get your house wiring checked for faults.
Phil.
Title: Re: Orange 35RT humming/buzzing
Post by: PMc on March 16, 2023, 10:31:16 PM
Do you have LED lighting? Or florescent? Those things can be noisy.